Anticipated schedule of the number of retained Sitz markers on serial daily abdominal radiographs in a 20 Sitz marker exam. Day number is in the left column and retained Sitz marker number is in the right column.
\\n\\n
Released this past November, the list is based on data collected from the Web of Science and highlights some of the world’s most influential scientific minds by naming the researchers whose publications over the previous decade have included a high number of Highly Cited Papers placing them among the top 1% most-cited.
\\n\\nWe wish to congratulate all of the researchers named and especially our authors on this amazing accomplishment! We are happy and proud to share in their success!
Note: Edited in March 2021
\\n"}]',published:!0,mainMedia:{caption:"Highly Cited",originalUrl:"/media/original/117"}},components:[{type:"htmlEditorComponent",content:'IntechOpen is proud to announce that 191 of our authors have made the Clarivate™ Highly Cited Researchers List for 2020, ranking them among the top 1% most-cited.
\n\nThroughout the years, the list has named a total of 261 IntechOpen authors as Highly Cited. Of those researchers, 69 have been featured on the list multiple times.
\n\n\n\nReleased this past November, the list is based on data collected from the Web of Science and highlights some of the world’s most influential scientific minds by naming the researchers whose publications over the previous decade have included a high number of Highly Cited Papers placing them among the top 1% most-cited.
\n\nWe wish to congratulate all of the researchers named and especially our authors on this amazing accomplishment! We are happy and proud to share in their success!
Note: Edited in March 2021
\n'}],latestNews:[{slug:"intechopen-supports-asapbio-s-new-initiative-publish-your-reviews-20220729",title:"IntechOpen Supports ASAPbio’s New Initiative Publish Your Reviews"},{slug:"webinar-introduction-to-open-science-wednesday-18-may-1-pm-cest-20220518",title:"Webinar: Introduction to Open Science | Wednesday 18 May, 1 PM CEST"},{slug:"step-in-the-right-direction-intechopen-launches-a-portfolio-of-open-science-journals-20220414",title:"Step in the Right Direction: IntechOpen Launches a Portfolio of Open Science Journals"},{slug:"let-s-meet-at-london-book-fair-5-7-april-2022-olympia-london-20220321",title:"Let’s meet at London Book Fair, 5-7 April 2022, Olympia London"},{slug:"50-books-published-as-part-of-intechopen-and-knowledge-unlatched-ku-collaboration-20220316",title:"50 Books published as part of IntechOpen and Knowledge Unlatched (KU) Collaboration"},{slug:"intechopen-joins-the-united-nations-sustainable-development-goals-publishers-compact-20221702",title:"IntechOpen joins the United Nations Sustainable Development Goals Publishers Compact"},{slug:"intechopen-signs-exclusive-representation-agreement-with-lsr-libros-servicios-y-representaciones-s-a-de-c-v-20211123",title:"IntechOpen Signs Exclusive Representation Agreement with LSR Libros Servicios y Representaciones S.A. de C.V"},{slug:"intechopen-expands-partnership-with-research4life-20211110",title:"IntechOpen Expands Partnership with Research4Life"}]},book:{item:{type:"book",id:"213",leadTitle:null,fullTitle:"Environmental Management in Practice",title:"Environmental Management in Practice",subtitle:null,reviewType:"peer-reviewed",abstract:"In recent years the topic of environmental management has become very common. In sustainable development conditions, central and local governments much more often notice the need of acting in ways that diminish negative impact on environment. Environmental management may take place on many different levels - starting from global level, e.g. climate changes, through national and regional level (environmental policy) and ending on micro level. This publication shows many examples of environmental management. The diversity of presented aspects within environmental management and approaching the subject from the perspective of various countries contributes greatly to the development of environmental management field of research.",isbn:null,printIsbn:"978-953-307-358-3",pdfIsbn:"978-953-51-6018-2",doi:"10.5772/738",price:139,priceEur:155,priceUsd:179,slug:"environmental-management-in-practice",numberOfPages:460,isOpenForSubmission:!1,isInWos:null,isInBkci:!1,hash:"a3a1aedd300eee04cacc8743f6fb60d0",bookSignature:"Elzbieta Broniewicz",publishedDate:"July 5th 2011",coverURL:"https://cdn.intechopen.com/books/images_new/213.jpg",numberOfDownloads:118820,numberOfWosCitations:87,numberOfCrossrefCitations:44,numberOfCrossrefCitationsByBook:0,numberOfDimensionsCitations:113,numberOfDimensionsCitationsByBook:0,hasAltmetrics:1,numberOfTotalCitations:244,isAvailableForWebshopOrdering:!0,dateEndFirstStepPublish:"October 19th 2010",dateEndSecondStepPublish:"November 16th 2010",dateEndThirdStepPublish:"March 23rd 2011",dateEndFourthStepPublish:"April 22nd 2011",dateEndFifthStepPublish:"June 21st 2011",currentStepOfPublishingProcess:5,indexedIn:"1,2,3,4,5,6,7",editedByType:"Edited by",kuFlag:!1,featuredMarkup:null,editors:[{id:"30436",title:"Dr.",name:"Elzbieta",middleName:null,surname:"Broniewicz",slug:"elzbieta-broniewicz",fullName:"Elzbieta Broniewicz",profilePictureURL:"https://mts.intechopen.com/storage/users/30436/images/1814_n.jpg",biography:"Dr. Elzbieta Broniewicz is a graduate of environmental engineering on Technical University in Bialystok, Poland. In 1998 she received her PhD in the field of economics. In her teaching and scientific work she combines engineering with economics. The main fields of her interest are: environmental expenditure accounts, environmental goods and services sector, environmental management system and environmental impact assessment.",institutionString:null,position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"1",totalChapterViews:"0",totalEditedBooks:"1",institution:null}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,coeditorOne:null,coeditorTwo:null,coeditorThree:null,coeditorFour:null,coeditorFive:null,topics:[{id:"782",title:"Environmental Management",slug:"engineering-environmental-engineering-environmental-management"}],chapters:[{id:"16280",title:"Curbing Climate Change through a National Development of Climate Change Policy",doi:"10.5772/18444",slug:"curbing-climate-change-through-a-national-development-of-climate-change-policy",totalDownloads:3207,totalCrossrefCites:0,totalDimensionsCites:2,hasAltmetrics:0,abstract:null,signatures:"Sumiani Yusoff",downloadPdfUrl:"/chapter/pdf-download/16280",previewPdfUrl:"/chapter/pdf-preview/16280",authors:[{id:"31519",title:"Prof.",name:"Sumiani",surname:"Yusoff",slug:"sumiani-yusoff",fullName:"Sumiani Yusoff"}],corrections:null},{id:"16281",title:"Environmental Protection Expenditure in European Union",doi:"10.5772/18110",slug:"environmental-protection-expenditure-in-european-union",totalDownloads:3173,totalCrossrefCites:3,totalDimensionsCites:3,hasAltmetrics:0,abstract:null,signatures:"Elzbieta Broniewicz",downloadPdfUrl:"/chapter/pdf-download/16281",previewPdfUrl:"/chapter/pdf-preview/16281",authors:[{id:"30436",title:"Dr.",name:"Elzbieta",surname:"Broniewicz",slug:"elzbieta-broniewicz",fullName:"Elzbieta Broniewicz"},{id:"128341",title:"Dr.",name:"Elzbieta",surname:"Broniewicz",slug:"elzbieta-broniewicz",fullName:"Elzbieta Broniewicz"}],corrections:null},{id:"16282",title:"Community Ecology and Capacity: Advancing Environmental Communication Strategies among Diverse Stakeholders",doi:"10.5772/17240",slug:"community-ecology-and-capacity-advancing-environmental-communication-strategies-among-diverse-stakeh",totalDownloads:2085,totalCrossrefCites:0,totalDimensionsCites:0,hasAltmetrics:0,abstract:null,signatures:"Rosemary M. Caron, Michael E. Rezaee and Danielle Dionne",downloadPdfUrl:"/chapter/pdf-download/16282",previewPdfUrl:"/chapter/pdf-preview/16282",authors:[{id:"27731",title:"Dr.",name:"Rosemary",surname:"Caron",slug:"rosemary-caron",fullName:"Rosemary Caron"},{id:"62766",title:"MSc",name:"Michael",surname:"Rezaee",slug:"michael-rezaee",fullName:"Michael Rezaee"},{id:"62767",title:"BSc",name:"Danielle",surname:"Dionne",slug:"danielle-dionne",fullName:"Danielle Dionne"}],corrections:null},{id:"16283",title:"Regional Issues in Environmental Management",doi:"10.5772/17267",slug:"regional-issues-in-environmental-management",totalDownloads:2755,totalCrossrefCites:0,totalDimensionsCites:0,hasAltmetrics:0,abstract:null,signatures:"Hiroyuki Taguchi",downloadPdfUrl:"/chapter/pdf-download/16283",previewPdfUrl:"/chapter/pdf-preview/16283",authors:[{id:"27814",title:"Dr.",name:"Hiroyuki",surname:"Taguchi",slug:"hiroyuki-taguchi",fullName:"Hiroyuki Taguchi"}],corrections:null},{id:"16284",title:"Geo-environmental Terrain Assessments Based on Remote Sensing Tools: A Review of Applications to Hazard Mapping and Control",doi:"10.5772/24487",slug:"geo-environmental-terrain-assessments-based-on-remote-sensing-tools-a-review-of-applications-to-haza",totalDownloads:3852,totalCrossrefCites:1,totalDimensionsCites:1,hasAltmetrics:0,abstract:null,signatures:"Paulo Cesar Fernandes da Silva and John Canning Cripps",downloadPdfUrl:"/chapter/pdf-download/16284",previewPdfUrl:"/chapter/pdf-preview/16284",authors:[{id:"57700",title:"Dr.",name:"Paulo",surname:"Fernandes-Da-Silva",slug:"paulo-fernandes-da-silva",fullName:"Paulo Fernandes-Da-Silva"},{id:"57702",title:"Dr.",name:"John",surname:"Cripps",slug:"john-cripps",fullName:"John Cripps"}],corrections:null},{id:"16285",title:"The Implementation of IPPC Directive in the Mediterranean Area",doi:"10.5772/17894",slug:"the-implementation-of-ippc-directive-in-the-mediterranean-area",totalDownloads:2708,totalCrossrefCites:1,totalDimensionsCites:4,hasAltmetrics:0,abstract:null,signatures:"Tiberio Daddi, Maria Rosa De Giacomo, Marco Frey, Francesco Testa and Fabio Iraldo",downloadPdfUrl:"/chapter/pdf-download/16285",previewPdfUrl:"/chapter/pdf-preview/16285",authors:[{id:"22437",title:"Prof.",name:"Marco",surname:"Frey",slug:"marco-frey",fullName:"Marco Frey"},{id:"29753",title:"Dr.",name:"Tiberio",surname:"Daddi",slug:"tiberio-daddi",fullName:"Tiberio Daddi"},{id:"43318",title:"Dr.",name:"Maria Rosa",surname:"De Giacomo",slug:"maria-rosa-de-giacomo",fullName:"Maria Rosa De Giacomo"},{id:"43319",title:"Dr.",name:"Francesco",surname:"Testa",slug:"francesco-testa",fullName:"Francesco Testa"},{id:"43320",title:"Prof.",name:"Fabio",surname:"Iraldo",slug:"fabio-iraldo",fullName:"Fabio Iraldo"}],corrections:null},{id:"16286",title:"Contaminated Sites and Public Policies in Sao Paulo State, Brazil",doi:"10.5772/21748",slug:"contaminated-sites-and-public-policies-in-sao-paulo-state-brazil",totalDownloads:2673,totalCrossrefCites:0,totalDimensionsCites:1,hasAltmetrics:0,abstract:null,signatures:"Ana Luiza Silva Spínola and Arlindo Philippi Jr.",downloadPdfUrl:"/chapter/pdf-download/16286",previewPdfUrl:"/chapter/pdf-preview/16286",authors:[{id:"44596",title:"MSc",name:"Ana Luiza",surname:"Spínola",slug:"ana-luiza-spinola",fullName:"Ana Luiza Spínola"},{id:"128360",title:"Prof.",name:"Arlindo",surname:"Philippi",slug:"arlindo-philippi",fullName:"Arlindo Philippi"}],corrections:null},{id:"16287",title:"Sustainable Management of Muddy Coastlines",doi:"10.5772/intechopen.84013",slug:"sustainable-management-of-muddy-coastlines",totalDownloads:3054,totalCrossrefCites:0,totalDimensionsCites:0,hasAltmetrics:0,abstract:null,signatures:"Steven Odi-Owei and Itolima Ologhadien",downloadPdfUrl:"/chapter/pdf-download/16287",previewPdfUrl:"/chapter/pdf-preview/16287",authors:[{id:"46130",title:"Prof.",name:"Steven",surname:"Odi-Owei",slug:"steven-odi-owei",fullName:"Steven Odi-Owei"},{id:"46154",title:"Mr.",name:"Itolima",surname:"Ologhadien",slug:"itolima-ologhadien",fullName:"Itolima Ologhadien"}],corrections:null},{id:"16288",title:"Indicators of Sustainable Business Practices",doi:"10.5772/17254",slug:"indicators-of-sustainable-business-practices",totalDownloads:5136,totalCrossrefCites:3,totalDimensionsCites:10,hasAltmetrics:1,abstract:null,signatures:"Hyunkee Bae and Richard S. Smardon",downloadPdfUrl:"/chapter/pdf-download/16288",previewPdfUrl:"/chapter/pdf-preview/16288",authors:[{id:"27772",title:"Dr.",name:"Hyunkee",surname:"Bae",slug:"hyunkee-bae",fullName:"Hyunkee Bae"},{id:"76107",title:"Prof.",name:"Richard",surname:"Smardon",slug:"richard-smardon",fullName:"Richard Smardon"}],corrections:null},{id:"16289",title:"Assessment of Industrial Pollution Load in Lagos, Nigeria by Industrial Pollution Projection System (IPPS) versus Effluent Analysis",doi:"10.5772/23353",slug:"assessment-of-industrial-pollution-load-in-lagos-nigeria-by-industrial-pollution-projection-system-i",totalDownloads:6194,totalCrossrefCites:0,totalDimensionsCites:2,hasAltmetrics:1,abstract:null,signatures:"Adebola Oketola and Oladele Osibanjo",downloadPdfUrl:"/chapter/pdf-download/16289",previewPdfUrl:"/chapter/pdf-preview/16289",authors:[{id:"51675",title:"Dr.",name:"Adebola",surname:"Adeyi",slug:"adebola-adeyi",fullName:"Adebola Adeyi"},{id:"58376",title:"Prof.",name:"Oladele",surname:"Osibanjo",slug:"oladele-osibanjo",fullName:"Oladele Osibanjo"}],corrections:null},{id:"16290",title:"Pollution Prevention in the Pulp and Paper Industries",doi:"10.5772/23709",slug:"pollution-prevention-in-the-pulp-and-paper-industries",totalDownloads:30871,totalCrossrefCites:9,totalDimensionsCites:33,hasAltmetrics:1,abstract:null,signatures:"Bahar K. Ince, Zeynep Cetecioglu and Orhan Ince",downloadPdfUrl:"/chapter/pdf-download/16290",previewPdfUrl:"/chapter/pdf-preview/16290",authors:[{id:"48845",title:"Prof.",name:"Orhan",surname:"Ince",slug:"orhan-ince",fullName:"Orhan Ince"},{id:"53263",title:"Dr.",name:"Zeynep",surname:"Cetecioglu",slug:"zeynep-cetecioglu",fullName:"Zeynep Cetecioglu"},{id:"56506",title:"Prof.",name:"Bahar",surname:"Ince",slug:"bahar-ince",fullName:"Bahar Ince"}],corrections:null},{id:"16291",title:"Retrofit Approach for the Reduction of Water and Energy Consumption in Pulp and Paper Production Processes",doi:"10.5772/20882",slug:"retrofit-approach-for-the-reduction-of-water-and-energy-consumption-in-pulp-and-paper-production-pro",totalDownloads:4073,totalCrossrefCites:1,totalDimensionsCites:3,hasAltmetrics:0,abstract:null,signatures:"Jesus Martinez Patino and Martin Picon Nunez",downloadPdfUrl:"/chapter/pdf-download/16291",previewPdfUrl:"/chapter/pdf-preview/16291",authors:[{id:"40882",title:"Dr.",name:"Jesús",surname:"Martinez-Patino",slug:"jesus-martinez-patino",fullName:"Jesús Martinez-Patino"},{id:"46888",title:"Dr.",name:"Martín",surname:"Picon-Nunez",slug:"martin-picon-nunez",fullName:"Martín Picon-Nunez"}],corrections:null},{id:"16292",title:"An Application Model for Sustainability in the Construction Industry",doi:"10.5772/22500",slug:"an-application-model-for-sustainability-in-the-construction-industry",totalDownloads:2784,totalCrossrefCites:0,totalDimensionsCites:0,hasAltmetrics:0,abstract:null,signatures:"Fernando Beiriz and Assed Haddad",downloadPdfUrl:"/chapter/pdf-download/16292",previewPdfUrl:"/chapter/pdf-preview/16292",authors:[{id:"27454",title:"Prof.",name:"Assed",surname:"Haddad",slug:"assed-haddad",fullName:"Assed Haddad"},{id:"47945",title:"Prof.",name:"Fernando",surname:"Beiriz",slug:"fernando-beiriz",fullName:"Fernando Beiriz"}],corrections:null},{id:"16293",title:"Assessing the SMEs’ Competitive Strategies on the Impact of Environmental Factors: A Quantitative SWOT Analysis Application",doi:"10.5772/21472",slug:"assessing-the-smes-competitive-strategies-on-the-impact-of-environmental-factors-a-quantitative-swot",totalDownloads:3778,totalCrossrefCites:2,totalDimensionsCites:4,hasAltmetrics:0,abstract:null,signatures:"Hui-Lin Hai",downloadPdfUrl:"/chapter/pdf-download/16293",previewPdfUrl:"/chapter/pdf-preview/16293",authors:[{id:"43205",title:"Prof.",name:"Hui Lin",surname:"Hai",slug:"hui-lin-hai",fullName:"Hui Lin Hai"}],corrections:null},{id:"16294",title:"Implementation of ISO 14000 in Luggage Manufacturing Industry: A Case Study",doi:"10.5772/17278",slug:"implementation-of-iso-14000-in-luggage-manufacturing-industry-a-case-study",totalDownloads:5538,totalCrossrefCites:0,totalDimensionsCites:0,hasAltmetrics:0,abstract:null,signatures:"S. B. Jaju",downloadPdfUrl:"/chapter/pdf-download/16294",previewPdfUrl:"/chapter/pdf-preview/16294",authors:[{id:"27839",title:"Dr.",name:"Santosh",surname:"Jaju",slug:"santosh-jaju",fullName:"Santosh Jaju"}],corrections:null},{id:"16295",title:"The Statistical Distributions of Industrial Wastes: an Analysis of the Japanese Establishment Linked Input-output Data",doi:"10.5772/18177",slug:"the-statistical-distributions-of-industrial-wastes-an-analysis-of-the-japanese-establishment-linked-",totalDownloads:2267,totalCrossrefCites:0,totalDimensionsCites:0,hasAltmetrics:0,abstract:null,signatures:"Hitoshi Hayami and Masao Nakamura",downloadPdfUrl:"/chapter/pdf-download/16295",previewPdfUrl:"/chapter/pdf-preview/16295",authors:[{id:"30662",title:"Prof.",name:"Masao",surname:"Nakamura",slug:"masao-nakamura",fullName:"Masao Nakamura"},{id:"37239",title:"Prof.",name:"Hitoshi",surname:"Hayami",slug:"hitoshi-hayami",fullName:"Hitoshi Hayami"}],corrections:null},{id:"16296",title:"The Effects of Paper Recycling and its Environmental Impact",doi:"10.5772/23110",slug:"the-effects-of-paper-recycling-and-its-environmental-impact",totalDownloads:12172,totalCrossrefCites:15,totalDimensionsCites:30,hasAltmetrics:0,abstract:null,signatures:"Iveta Cabalova, Frantisek Kacik, Anton Geffert and Danica Kacikova",downloadPdfUrl:"/chapter/pdf-download/16296",previewPdfUrl:"/chapter/pdf-preview/16296",authors:[{id:"50631",title:"Dr.",name:"Iveta",surname:"Čabalová",slug:"iveta-cabalova",fullName:"Iveta Čabalová"},{id:"50672",title:"Prof.",name:"František",surname:"Kačík",slug:"frantisek-kacik",fullName:"František Kačík"},{id:"50673",title:"Dr.",name:"Danica",surname:"Kačíková",slug:"danica-kacikova",fullName:"Danica Kačíková"},{id:"50674",title:"Dr.",name:"Anton",surname:"Geffert",slug:"anton-geffert",fullName:"Anton Geffert"}],corrections:null},{id:"16297",title:"Overview Management Chemical Residues of Laboratories in Academic Institutions in Brazil",doi:"10.5772/17181",slug:"overview-management-chemical-residues-of-laboratories-in-academic-institutions-in-brazil",totalDownloads:3182,totalCrossrefCites:0,totalDimensionsCites:0,hasAltmetrics:0,abstract:null,signatures:"Patrícia Carla Giloni-Lima, Vanderlei Aparecido de Lima and Adriana Massaê Kataoka",downloadPdfUrl:"/chapter/pdf-download/16297",previewPdfUrl:"/chapter/pdf-preview/16297",authors:[{id:"27508",title:"Dr.",name:"Patricia Carla",surname:"Giloni",slug:"patricia-carla-giloni",fullName:"Patricia Carla Giloni"},{id:"45416",title:"Dr.",name:"Adriana Massaê",surname:"Kataoka",slug:"adriana-massae-kataoka",fullName:"Adriana Massaê Kataoka"},{id:"45427",title:"Dr.",name:"Vanderlei Aparecido de",surname:"Lima",slug:"vanderlei-aparecido-de-lima",fullName:"Vanderlei Aparecido de Lima"},{id:"128370",title:"Prof.",name:"Vanderlei Aparecido De",surname:"Lima",slug:"vanderlei-aparecido-de-lima",fullName:"Vanderlei Aparecido De Lima"}],corrections:null},{id:"16298",title:"Lengthening Biolubricants' Lifetime by Using Porous Materials",doi:"10.5772/22302",slug:"lengthening-biolubricants-lifetime-by-using-porous-materials",totalDownloads:3598,totalCrossrefCites:1,totalDimensionsCites:1,hasAltmetrics:0,abstract:null,signatures:"Estibaliz Aranzabe, Arrate Marcaide, Marta Hernaiz and Nerea Uranga",downloadPdfUrl:"/chapter/pdf-download/16298",previewPdfUrl:"/chapter/pdf-preview/16298",authors:[{id:"47154",title:"Mrs.",name:"Estibaliz",surname:"Aranzabe",slug:"estibaliz-aranzabe",fullName:"Estibaliz Aranzabe"},{id:"47163",title:"Mrs.",name:"Arrate",surname:"Marcaide",slug:"arrate-marcaide",fullName:"Arrate Marcaide"},{id:"47164",title:"Mrs.",name:"Marta",surname:"Hernaiz",slug:"marta-hernaiz",fullName:"Marta Hernaiz"},{id:"47165",title:"Mrs.",name:"Nerea",surname:"Uranga",slug:"nerea-uranga",fullName:"Nerea Uranga"}],corrections:null},{id:"16299",title:"A Fuzzy Water Quality Index for Watershed Quality Analysis and Management",doi:"10.5772/20316",slug:"a-fuzzy-water-quality-index-for-watershed-quality-analysis-and-management",totalDownloads:4341,totalCrossrefCites:5,totalDimensionsCites:11,hasAltmetrics:0,abstract:null,signatures:"André Lermontov, Lidia Yokoyama, Mihail Lermontov and Maria Augusta Soares Machado",downloadPdfUrl:"/chapter/pdf-download/16299",previewPdfUrl:"/chapter/pdf-preview/16299",authors:[{id:"38386",title:"Dr",name:"André",surname:"Lermontov",slug:"andre-lermontov",fullName:"André Lermontov"},{id:"44333",title:"Dr.",name:"Lidia",surname:"Yokoyama",slug:"lidia-yokoyama",fullName:"Lidia Yokoyama"},{id:"44334",title:"Dr.",name:"Mihail",surname:"Lermontov",slug:"mihail-lermontov",fullName:"Mihail Lermontov"},{id:"44335",title:"Prof.",name:"Maria Augusta",surname:"Soares Machado",slug:"maria-augusta-soares-machado",fullName:"Maria Augusta Soares Machado"}],corrections:null},{id:"16300",title:"Environmental Management of Wastewater Treatment Plants – the Added Value of the Ecotoxicological Approach",doi:"10.5772/18389",slug:"environmental-management-of-wastewater-treatment-plants-the-added-value-of-the-ecotoxicological-appr",totalDownloads:6098,totalCrossrefCites:2,totalDimensionsCites:3,hasAltmetrics:0,abstract:null,signatures:"Elsa Mendonça, Ana Picado,\nMaria Ana Cunha and Justina Catarino",downloadPdfUrl:"/chapter/pdf-download/16300",previewPdfUrl:"/chapter/pdf-preview/16300",authors:[{id:"31349",title:"Dr.",name:"Elsa",surname:"Mendonça",slug:"elsa-mendonca",fullName:"Elsa Mendonça"},{id:"44246",title:"Dr.",name:"Ana",surname:"Picado",slug:"ana-picado",fullName:"Ana Picado"},{id:"44247",title:"Mr.",name:"Maria Ana",surname:"Cunha",slug:"maria-ana-cunha",fullName:"Maria Ana Cunha"},{id:"44266",title:"Dr.",name:"Justina",surname:"Catarino",slug:"justina-catarino",fullName:"Justina Catarino"}],corrections:null},{id:"16301",title:"Technology Roadmap for Wastewater Reuse in Petroleum Refineries in Brazil",doi:"10.5772/20297",slug:"technology-roadmap-for-wastewater-reuse-in-petroleum-refineries-in-brazil",totalDownloads:5284,totalCrossrefCites:1,totalDimensionsCites:5,hasAltmetrics:0,abstract:null,signatures:"Felipe Pombo, Alessandra Magrini and Alexandre Szklo",downloadPdfUrl:"/chapter/pdf-download/16301",previewPdfUrl:"/chapter/pdf-preview/16301",authors:[{id:"38305",title:"MSc",name:"Felipe",surname:"Pombo",slug:"felipe-pombo",fullName:"Felipe Pombo"},{id:"43382",title:"Dr.",name:"Alessandra",surname:"Magrini",slug:"alessandra-magrini",fullName:"Alessandra Magrini"},{id:"43383",title:"Dr.",name:"Alexandre",surname:"Szklo",slug:"alexandre-szklo",fullName:"Alexandre Szklo"}],corrections:null}],productType:{id:"1",title:"Edited Volume",chapterContentType:"chapter",authoredCaption:"Edited by"},subseries:null,tags:null},relatedBooks:[{type:"book",id:"610",title:"Environmental Monitoring",subtitle:null,isOpenForSubmission:!1,hash:"d969c446da0e9fd096144fc7260725e4",slug:"environmental-monitoring",bookSignature:"Ema O. Ekundayo",coverURL:"https://cdn.intechopen.com/books/images_new/610.jpg",editedByType:"Edited by",editors:[{id:"72005",title:"Dr",name:"Ema",surname:"Ekundayo",slug:"ema-ekundayo",fullName:"Ema Ekundayo"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"403",title:"Planet Earth 2011",subtitle:"Global Warming Challenges and Opportunities for Policy and Practice",isOpenForSubmission:!1,hash:"52a6385d63c583025b22d5e45871d054",slug:"planet-earth-2011-global-warming-challenges-and-opportunities-for-policy-and-practice",bookSignature:"Elias G. Carayannis",coverURL:"https://cdn.intechopen.com/books/images_new/403.jpg",editedByType:"Edited by",editors:[{id:"62806",title:"Prof.",name:"Elias",surname:"Carayannis",slug:"elias-carayannis",fullName:"Elias Carayannis"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10405",title:"River Basin Management",subtitle:"Sustainability Issues and Planning Strategies",isOpenForSubmission:!1,hash:"5e5ddd0f2eda107ce19c4c06a55a8351",slug:"river-basin-management-sustainability-issues-and-planning-strategies",bookSignature:"José Simão Antunes Do Carmo",coverURL:"https://cdn.intechopen.com/books/images_new/10405.jpg",editedByType:"Edited by",editors:[{id:"67904",title:"Prof.",name:"José Simão",surname:"Antunes Do Carmo",slug:"jose-simao-antunes-do-carmo",fullName:"José Simão Antunes Do Carmo"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"1591",title:"Infrared Spectroscopy",subtitle:"Materials Science, Engineering and Technology",isOpenForSubmission:!1,hash:"99b4b7b71a8caeb693ed762b40b017f4",slug:"infrared-spectroscopy-materials-science-engineering-and-technology",bookSignature:"Theophile Theophanides",coverURL:"https://cdn.intechopen.com/books/images_new/1591.jpg",editedByType:"Edited by",editors:[{id:"37194",title:"Dr.",name:"Theophile",surname:"Theophanides",slug:"theophile-theophanides",fullName:"Theophile Theophanides"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"3161",title:"Frontiers in Guided Wave Optics and Optoelectronics",subtitle:null,isOpenForSubmission:!1,hash:"deb44e9c99f82bbce1083abea743146c",slug:"frontiers-in-guided-wave-optics-and-optoelectronics",bookSignature:"Bishnu Pal",coverURL:"https://cdn.intechopen.com/books/images_new/3161.jpg",editedByType:"Edited by",editors:[{id:"4782",title:"Prof.",name:"Bishnu",surname:"Pal",slug:"bishnu-pal",fullName:"Bishnu Pal"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"371",title:"Abiotic Stress in Plants",subtitle:"Mechanisms and Adaptations",isOpenForSubmission:!1,hash:"588466f487e307619849d72389178a74",slug:"abiotic-stress-in-plants-mechanisms-and-adaptations",bookSignature:"Arun Shanker and B. Venkateswarlu",coverURL:"https://cdn.intechopen.com/books/images_new/371.jpg",editedByType:"Edited by",editors:[{id:"58592",title:"Dr.",name:"Arun",surname:"Shanker",slug:"arun-shanker",fullName:"Arun Shanker"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"3092",title:"Anopheles mosquitoes",subtitle:"New insights into malaria vectors",isOpenForSubmission:!1,hash:"c9e622485316d5e296288bf24d2b0d64",slug:"anopheles-mosquitoes-new-insights-into-malaria-vectors",bookSignature:"Sylvie Manguin",coverURL:"https://cdn.intechopen.com/books/images_new/3092.jpg",editedByType:"Edited by",editors:[{id:"50017",title:"Prof.",name:"Sylvie",surname:"Manguin",slug:"sylvie-manguin",fullName:"Sylvie Manguin"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"72",title:"Ionic Liquids",subtitle:"Theory, Properties, New Approaches",isOpenForSubmission:!1,hash:"d94ffa3cfa10505e3b1d676d46fcd3f5",slug:"ionic-liquids-theory-properties-new-approaches",bookSignature:"Alexander Kokorin",coverURL:"https://cdn.intechopen.com/books/images_new/72.jpg",editedByType:"Edited by",editors:[{id:"19816",title:"Prof.",name:"Alexander",surname:"Kokorin",slug:"alexander-kokorin",fullName:"Alexander Kokorin"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"2270",title:"Fourier Transform",subtitle:"Materials Analysis",isOpenForSubmission:!1,hash:"5e094b066da527193e878e160b4772af",slug:"fourier-transform-materials-analysis",bookSignature:"Salih Mohammed Salih",coverURL:"https://cdn.intechopen.com/books/images_new/2270.jpg",editedByType:"Edited by",editors:[{id:"111691",title:"Dr.Ing.",name:"Salih",surname:"Salih",slug:"salih-salih",fullName:"Salih Salih"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"117",title:"Artificial Neural Networks",subtitle:"Methodological Advances and Biomedical Applications",isOpenForSubmission:!1,hash:null,slug:"artificial-neural-networks-methodological-advances-and-biomedical-applications",bookSignature:"Kenji Suzuki",coverURL:"https://cdn.intechopen.com/books/images_new/117.jpg",editedByType:"Edited by",editors:[{id:"3095",title:"Prof.",name:"Kenji",surname:"Suzuki",slug:"kenji-suzuki",fullName:"Kenji Suzuki"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}],ofsBooks:[]},correction:{item:{id:"79356",slug:"corrigendum-to-textured-bst-thin-film-on-silicon-substrate-preparation-and-its-applications-for-high",title:"Corrigendum to: Textured BST Thin Film on Silicon Substrate: Preparation and Its Applications for High Frequency Tunable Devices",doi:null,correctionPDFUrl:"https://cdn.intechopen.com/pdfs/66064.pdf",downloadPdfUrl:"/chapter/pdf-download/66064",previewPdfUrl:"/chapter/pdf-preview/66064",totalDownloads:null,totalCrossrefCites:null,bibtexUrl:"/chapter/bibtex/66064",risUrl:"/chapter/ris/66064",chapter:{id:"62285",slug:"textured-bst-thin-film-on-silicon-substrate-preparation-and-its-applications-for-high-frequency-tuna",signatures:"Congchun Zhang, Jianze Huang, Chunsheng Yang and Guifu Ding",dateSubmitted:"February 7th 2018",dateReviewed:"June 3rd 2018",datePrePublished:"November 5th 2018",datePublished:"January 3rd 2019",book:{id:"7253",title:"Coatings and Thin-Film Technologies",subtitle:null,fullTitle:"Coatings and Thin-Film Technologies",slug:"coatings-and-thin-film-technologies",publishedDate:"January 3rd 2019",bookSignature:"Jaime Andres Perez-Taborda and Alba G. Avila Bernal",coverURL:"https://cdn.intechopen.com/books/images_new/7253.jpg",licenceType:"CC BY 3.0",editedByType:"Edited by",editors:[{id:"193020",title:"Dr.",name:"Jaime Andres",middleName:null,surname:"Perez Taborda",slug:"jaime-andres-perez-taborda",fullName:"Jaime Andres Perez Taborda"}],productType:{id:"1",title:"Edited Volume",chapterContentType:"chapter",authoredCaption:"Edited by"}},authors:[{id:"33329",title:"Prof.",name:"guifu",middleName:null,surname:"Ding",fullName:"guifu Ding",slug:"guifu-ding",email:"gfding@sjtu.edu.cn",position:null,institution:{name:"Shanghai Jiao Tong University",institutionURL:null,country:{name:"China"}}},{id:"244624",title:"Associate Prof.",name:"Congchun",middleName:null,surname:"Zhang",fullName:"Congchun Zhang",slug:"congchun-zhang",email:"zhcc@sjtu.edu.cn",position:null,institution:null},{id:"255541",title:"Mr.",name:"Jianze",middleName:null,surname:"Huang",fullName:"Jianze Huang",slug:"jianze-huang",email:"huangjz420@sjtu.edu.cn",position:null,institution:null},{id:"255547",title:"Mr.",name:"Chunsheng",middleName:null,surname:"Yang",fullName:"Chunsheng Yang",slug:"chunsheng-yang",email:"csyang@sjtu.edu.cn",position:null,institution:null}]}},chapter:{id:"62285",slug:"textured-bst-thin-film-on-silicon-substrate-preparation-and-its-applications-for-high-frequency-tuna",signatures:"Congchun Zhang, Jianze Huang, Chunsheng Yang and Guifu Ding",dateSubmitted:"February 7th 2018",dateReviewed:"June 3rd 2018",datePrePublished:"November 5th 2018",datePublished:"January 3rd 2019",book:{id:"7253",title:"Coatings and Thin-Film Technologies",subtitle:null,fullTitle:"Coatings and Thin-Film Technologies",slug:"coatings-and-thin-film-technologies",publishedDate:"January 3rd 2019",bookSignature:"Jaime Andres Perez-Taborda and Alba G. Avila Bernal",coverURL:"https://cdn.intechopen.com/books/images_new/7253.jpg",licenceType:"CC BY 3.0",editedByType:"Edited by",editors:[{id:"193020",title:"Dr.",name:"Jaime Andres",middleName:null,surname:"Perez Taborda",slug:"jaime-andres-perez-taborda",fullName:"Jaime Andres Perez Taborda"}],productType:{id:"1",title:"Edited Volume",chapterContentType:"chapter",authoredCaption:"Edited by"}},authors:[{id:"33329",title:"Prof.",name:"guifu",middleName:null,surname:"Ding",fullName:"guifu Ding",slug:"guifu-ding",email:"gfding@sjtu.edu.cn",position:null,institution:{name:"Shanghai Jiao Tong University",institutionURL:null,country:{name:"China"}}},{id:"244624",title:"Associate Prof.",name:"Congchun",middleName:null,surname:"Zhang",fullName:"Congchun Zhang",slug:"congchun-zhang",email:"zhcc@sjtu.edu.cn",position:null,institution:null},{id:"255541",title:"Mr.",name:"Jianze",middleName:null,surname:"Huang",fullName:"Jianze Huang",slug:"jianze-huang",email:"huangjz420@sjtu.edu.cn",position:null,institution:null},{id:"255547",title:"Mr.",name:"Chunsheng",middleName:null,surname:"Yang",fullName:"Chunsheng Yang",slug:"chunsheng-yang",email:"csyang@sjtu.edu.cn",position:null,institution:null}]},book:{id:"7253",title:"Coatings and Thin-Film Technologies",subtitle:null,fullTitle:"Coatings and Thin-Film Technologies",slug:"coatings-and-thin-film-technologies",publishedDate:"January 3rd 2019",bookSignature:"Jaime Andres Perez-Taborda and Alba G. Avila Bernal",coverURL:"https://cdn.intechopen.com/books/images_new/7253.jpg",licenceType:"CC BY 3.0",editedByType:"Edited by",editors:[{id:"193020",title:"Dr.",name:"Jaime Andres",middleName:null,surname:"Perez Taborda",slug:"jaime-andres-perez-taborda",fullName:"Jaime Andres Perez Taborda"}],productType:{id:"1",title:"Edited Volume",chapterContentType:"chapter",authoredCaption:"Edited by"}}},ofsBook:{item:{type:"book",id:"11492",leadTitle:null,title:"Space Exploration - Advances in Research",subtitle:null,reviewType:"peer-reviewed",abstract:"\r\n\tThe purpose of the book is to provide information on new scientific findings in space exploration and their application to other fields. Space exploration provides a fundamental source of knowledge that will improve our understanding of nature and its influence on our views. Its achievements will be directed to phenomena that require a proper explanation involving the analysis of data in studies of the solar system together with views on the origin of the universe and its evolution. The book should also contain aspects involved in the physical description of new phenomena and determine the manner in which they modify our present views and the techniques that we employ. Such contributions should also be accompanied by studies of their effects on human activity including the development of devices that will improve global communication. The importance of the book will be properly assessed by the value of its contributions.
\r\n\t
Radiology plays a pivotal role in the detection of constipation, identification of underlying etiologies, and revealing associated complications. Imaging evaluation of constipation has evolved from radiography and contrast enemas to advanced cross-sectional and functional imaging. A dilemma that physicians of medical and surgical specialties encounter when confronted with a patient with constipation is the decision of if or when radiology is indicated. The clinical presentation of the patient and what information is desired will ultimately govern if imaging is warranted and then what is the most appropriate exam to order. If the patient presents in the acute setting with a potential surgical emergency, fast and widely available imaging exams, such as radiography or computed tomography (CT), are the most appropriate exams to order. If the patient has a chronic issue or data regarding colorectal function is desired, a colorectal transit time exam with Sitz markers or defecography with fluoroscopy or magnetic resonance (MR) imaging are the exams of choice. With a diverse range of anatomic and functional imaging tests available, radiology has developed into an invaluable mechanism in the assessment of patients with constipation.
\nRadiography, also known as plain film or X-ray, is a widely available, inexpensive, and easily obtained imaging test to assess for constipation. While the reported diagnostic sensitivity of radiography for the detection of constipation is 84%, the reported specificity is 72% [1]. Despite its relatively low sensitivity and specificity, radiographs serve as a basis for triage for further imaging work-up and assist in the therapeutic decision-making process. Inherent pitfalls in radiography of patients whom are constipated are other causes of colonic dilation, particularly adynamic ileus and colonic pseudo-obstruction [1].
\nRadiography is commonly used to image pediatric patients with constipation, particularly in the acute setting. However there is a unified consensus throughout the medical community to reduce non-essential and unnecessary radiation exposure to the pediatric population [2]. The latest consensus guidelines from the North American and European Societies of Pediatric Gastroenterology, Hepatology, and Nutrition advocate that constipation should be diagnosed clinically in pediatric patients because there is no reliable system to diagnose constipation and, instead, this modality may lead to misdiagnosis of more acute pathology [2]. Expert consensus also advocates that radiography has no role in imaging of children with functional constipation, which is best diagnosed with careful clinical assessment and physical examination [2].
\nAnteroposterior (AP) images of the abdomen and pelvis in the supine position are performed to visualize and qualify the burden of feces, visualize the size of the colon, and assess for colonic obstruction. Erect and lateral decubitus images of the abdomen and pelvis to may be added if there is concern for complications of constipation such as free air from a perforation [1].
\nThe key radiographic findings of constipation are the presence of large fecal burden throughout the colon, luminal fecalomas, and a relative paucity or absence of luminal gas [3]. Feces appear as soft tissue opacities with internal mottled air (Figures 1 and 2) [3].
\nAP radiograph of the abdomen and pelvis in a patient with constipation displays diffuse dilation of the colon (arrow) with an abrupt transition in luminal caliber by a large soft tissue opacity, which contains internal mottled air, indicative of feces (arrowhead).
AP radiograph of the abdomen and pelvis of patient with constipation shows a dilated colon with a transition in caliber due to a soft tissue opacity, which contains internal mottled air, characteristic of feces (arrow).
Radiography is helpful to assess for the presence of complications associated with constipation. Non-dependent images of the abdomen in the upright or left lateral decubitus positions may also be used for assessment of free air [1]. Bowel ischemia and infarction may be manifested on radiographs as pneumatosis, or air within the bowel wall, and/or portal venous gas, which projects over the silhouette of the liver [1]. Pneumoperitoneum from bowel perforation can be detected on radiography by air external to the bowel wall, air along the peritoneal ligaments, and air in the right upper abdominal quadrant [1]. If a surgical emergency is suspected on radiography, emergent surgical consultation is recommended. However, if surgery is not imminently planned or other treatment options are being considered, assessment of the severity and cause of the constipation with cross-sectional imaging becomes a priority. CT is the preferred imaging modality because of its superior sensitivity and specificity and it can potentially modify treatment.
\nTwo entities that mimic mechanical causes of constipation are adynamic paralytic ileus and acute colonic pseudo-obstruction. Adynamic paralytic ileus is commonly due to medications, metabolic abnormalities, and recent surgery. Acute colonic pseudo-obstruction, also known as Ogilvie’s Syndrome, is due to altered autonomic innervation of the colon and may also be caused by medications and metabolic disturbances [1].
\nAssessment of the small bowel and colon in pediatric patients may be challenging because the appearances, fold pattern, and location of the small bowel and colon overlap more so than in adult patients. There is also no established system to diagnose constipation in pediatric patients. Therefore radiography may be misleading in the assessment of pediatric patients it may result in missed diagnoses; this modality should be used in children in a limited fashion.
\nA radiographic test that is used to estimate transit time of the colon is a Sitz marker exam [4]. In patients with constipation, this study may help discriminate between delayed colonic transit and defecation disorders.
\nPatients are instructed to discontinue laxatives or any pro-motility medications. Otherwise no preparation is needed. The most common technique used is the ingestion of 20 or 24 Sitz markers in a single dose with a meal. Sitz markers are small, plastic rings that contain radio-opaque material so they may be visible on radiographs (Figure 3) [4]. Then serial anteroposterior radiographic images of the abdomen and pelvis are obtained to monitor the clearance of the Sitz markers from the colon (Figure 4). A normal colonic transit time ranges between 24 and 56 h. Most patients will clear all of the Sitz markers in 4–5 days [4].
\nMagnified AP radiograph of the pelvis shows Sitz markers.
AP radiograph of the abdomen and pelvis in this patient on day 3 of a Sitz marker exam, 18 of 20 Sitz markers are present and indicate that colonic transit will be delayed at 5 days.
A normal colonic transit time, which is between 24 and 56 hours, corresponds to retention of less than 20% of the original Sitz markers at 5 days [4]. In a Sitz marker exam that used 20 Sitz markers, the anticipated schedule of the number of retained Sitz markers on serial daily abdominal radiographs is as follows (Table 1).
\nDay | \nSitz markers | \n
---|---|
1 | \n≤16 | \n
2 | \n≤8 | \n
3 | \n≤4 | \n
4 | \n≤2 | \n
5 | \n≤1 | \n
Anticipated schedule of the number of retained Sitz markers on serial daily abdominal radiographs in a 20 Sitz marker exam. Day number is in the left column and retained Sitz marker number is in the right column.
Fluoroscopy employs the administration of contrast with real-time, moving radiographs to image both anatomy and function. Two fluoroscopic imaging techniques used to evaluate patients with constipation are contrast enema and evacuation proctography exams.
\nContrast enema may be valuable in the initial imaging assessment of patients with constipation because of it allows delineation of mechanical causes of constipation by displaying the luminal size of the colon and rectum, site(s) of transition in luminal caliber, and the length of involvement [5]. This exam is unique because it may be both diagnostic and therapeutic: the instillation of contrast material into the colon and rectum may relieve fecal impaction [5].
\nPrior to the exam, patients undergo a bowel cleanse preparation with an oral laxative, such as magnesium citrate or polyethylene glycol. Contrast enema exams are performed with fluoroscopy and may be performed with either single contrast: barium or water-soluble contrast only or double contrast: barium or water-soluble contrast with the insufflation of air or carbon dioxide.
\nPre-procedural radiographic anteroposterior images of the abdomen and pelvis and a left lateral radiographic view of pelvis are obtained. The patient then lies in the left lateral decubitus position on the fluoroscopy table. A digital rectal exam in performed. Then a thin, small-gauge, flexible catheter is placed into the rectum. This catheter is typically paired with a small, balloon that is inflated to ensure that the catheter does not back out of the rectum. If double contrast is performed, air or carbon dioxide is gently insufflated by hand pump to patient tolerance. The contrast is then instilled into the rectum and colon by gravity. During contrast administration, fluoroscopic-guided spot radiographic left and right lateral and left and right posterior oblique images of the rectum, rectosigmoid junction, sigmoid colon, descending colon and splenic flexure are obtained. Then an anteroposterior view of the transverse colon and a left posterior oblique view of hepatic flexure are obtained. Finally anteroposterior and posterior oblique images of the ascending colon, cecum, ileocecal valve, and the terminal ileum, are obtained. At the end of the exam, the contrast is emptied out of the colon by gravity and a post evacuation anteroposterior radiographic view of the abdomen and pelvis is obtained.
\nContrast enema exams can depict filling defects in the colon and rectum from feces and fecalomas from constipation or an obstructive mass, such as malignancy (Figure 5) [5].
\nContrast enema image of the sigmoid colon in a patient with constipation and irregular bowel movements shows an abrupt transition (arrow) with obstruction of passage of contrast. The patient was referred for a colonoscopy and then surgery for resection of an adenocarcinoma.
Colonic and rectal luminal size and the presence, degree, and length of strictures are all displayed and can be assessed on contrast enemas [5, 6]. Strictures, which are due to fibrosis from repeated inflammation or de-vascularization, may be caused by diverticulitis (Figure 6), ischemia, prior radiation or surgery (Figure 7), and inflammatory bowel disease (Figure 8) [5, 6].
\nA patient with abnormal and irregular bowel movements and constipation following an episode of acute diverticulitis underwent a contrast enema. Adjacent to multiple diverticula (arrowhead) in the descending colon, there is focal, short-segment, low-grade stricture (arrow) from prior diverticulitis.
Contrast enema image of a patient with constipation and decreased bowel movements; she has a history of cervical cancer that was treated with radiation therapy. There is a short-segment, high-grade stricture (arrow) in the sigmoid colon due to prior radiation therapy.
A patient with ulcerative colitis underwent a contrast enema. AP image after evacuation of contrast shows contrast outlining diffuse colonic wall thickening (arrows) and dilatation with smooth tapering in the sigmoid colon (asterisk).
Contrast enema is a dynamic imaging modality in the assessment of pediatric patients with constipation [7]. Contrast enemas are invaluable in both the diagnosis and extent of involvement for Hirschsprung’s disease, an entity that results in constipation due aganglionosis, or absence of the ganglion cells, in the distal colon and rectum [7]. The denervated distal colon or rectum is small in luminal size with proximal dilation [7]. Early filling views of the sigmoid colon and rectum allow for detection of an abnormal sigmoid colon to rectum size ratio and fasciculation or saw-tooth irregularity of the denervated segment [7].
\nWhile contrast enema can reliably display these causes of constipation, computed tomography (CT) may characterize these entities with greater spatial and temporal resolution, in a shorter time, with improved patient comfort, and that is more available, particularly in the emergent setting [8]. CT also permits visualization of extra-colorectal structures [8]. Therefore these causes of constipation are discussed in further depth in the CT section of this chapter.
\nDefecography is a fluoroscopic exam that provides valuable data for patients with constipation that is caused by both anatomic and functional disorders, which range from pelvic floor dysfunction to spastic pelvic floor syndrome. This exam is typically performed in adult and adolescent patients whom may follow instructions for the dynamic portion of the exam.
\nPre-procedural bowel preparation consists of a bowel cleanse preparation with an oral laxative, such as magnesium citrate or polyethylene glycol. Barium may be administered in the vagina (5 mL barium instillation) and small bowel (500 mL barium oral ingestion) to simultaneously assess these structures in relation to the colon and rectum.
\nThe patient is placed on the fluoroscopy table in left lateral decubitus position. 120–240 mL of barium paste is introduced into the rectum with a large-bore, soft catheter. Then spot lateral radiographic images of the patient at rest in the left lateral decubitus position with knees flexed to recreate the seated position. The patient is then positioned in a special defecography chair. Continuous and spot right lateral images of the seated patient are obtained at rest at rest, during strain (Valsalva maneuver), and then during defecation. A post-evacuation image during strain is obtained to assess for retained barium paste.
\nDefecography is a highly sensitive modality for the detection and classification of rectocele and rectal prolapse [9, 10]. A rectocele is the abnormal bulging or protrusion of the rectal wall due to a fascial or ligamentous defect [10]. A rectocele may cause inhibit defecation due to weakening of the vector force during strain [9, 10]. Feces may become entrapped in rectoceles that in turn results in incomplete evacuation [9, 10]. The presence of an anterior rectocele (Figure 9) is indicative of a defect in the rectovaginal fascia whereas the presence of a posterior rectocele indicates a defect in the anococcygeal ligament [9, 10]. Rectal prolapse may cause constipation by infolding of the rectum that is caused by repetitive straining and fascial disruption [9, 10].
\nEvacuation image from a fluoroscopic defecography in a patient with difficult evacuation and constipation shows a mucosal, intra-rectal prolapse (arrow) and an anterior rectocele (arrowhead), which incompletely empties.
Rectoceles are measured and classified on the basis of distance of the anterior or posterior rectal wall from the anal canal axis [9, 11, 12]. Rectal prolapses are classified by mucosa-only or full wall-thickness involvement and intra-rectal, internal intra-anal, or external location (Figure 9) [9, 11, 12]. While fluoroscopic defecography has been shown to be highly sensitive for rectal prolapse detection, MR defecography allows for similarly reliable and accurate classification of rectocele and rectal prolapse type due to superior tissue resolution [12].
\nAs an analogue to fluoroscopic defecography, MR defecography plays a vital role in the management of patients with constipation that is caused by both anatomic and functional disorders, which range from pelvic floor dysfunction to spastic pelvic floor syndrome [9, 11, 12]. High resolution and dynamic MR techniques provide detailed anatomic and physiologic information of the colon, rectum, and pelvic floor [9, 11, 12]. This data may then be used to discriminate patients that need surgery from those that need more conservative therapy [9, 11, 12]. For example, many patients with rectoceles from pelvic floor dysfunction will never improve without surgical repair whereas patients with functional constipation are treated with positive biologic feedback [9, 11, 12].
\nMR defecography is typically performed in adult and adolescent patients whom may tolerate confined space of the bore of the magnet and follow instructions for the dynamic portion of the exam. Challenges to MR imaging are pre-procedural preparation and scan times that are longer than radiography or CT exams. Also MR imaging exams may be limited in certain patients because of claustrophobia, as well as medical devices and orthopedic metallic hardware.
\nPrior to the exam, patients undergo a bowel cleanse preparation with an oral laxative, such as magnesium citrate or polyethylene glycol, and fast for 6 h. The patient is instructed to use one rectal enema the night before the examination and another up to 1 h before the exam. The patient lies in the right decubitus position on an absorbent, waterproof pad on the MR table and approximately 100–150 mL of warmed ultrasound gel is instilled in the rectum with a flexible tube. In female patients, 60 mL of ultrasound gel may be instilled into the vagina for to simultaneously assess the vagina and cervix in relation to the colon and rectum.
\nSimple and clear communication is important to establish with the patient during the examination to ensure direct instructions are followed that will in turn yield the best possible images. A phased-array torso coil is used to acquire sagittal, coronal, and axial T2-weighted steady-state fast spin echo (SSFSE) MR images: 24–30 cm field of view (FOV), 6 mm thickness, 512 × 256 matrix, repetition time (TR) = 5170 ms, echo time (TE) = 137 ms, from the superior border of the pubic symphysis to the lower end of the anal canal. Are then obtained of the entire pelvis. T2-weighted MR images are helpful in assessing for wall edema or masses and accentuate mucosal features against a bright background created by rectal ultrasound gel contrast. The high-resolution images provide superb soft tissue detail for hernias and muscular or fascial defects.
\nDynamic fast imaging employing steady-state acquisition is then performed. The FOV is centered at the rectum and then imaging is performed at rest, during strain (Valsalva maneuver), and then during defecation. Serial, single-section mid-sagittal SSFSE MR images (30 cm FOV, 8 mm thickness, 256 × 256 matrix, TR = 3840 ms, TE = 1670 ms) are acquired every 2 s and repeated 15–20 times and viewed as a cine loop. Gradient echo imaging may also be used for the dynamic sequences. Imaging is also performed of the patient while performing squeeze maneuver to evaluate puborectalis muscle contraction. The use of these dynamic sequences allows real-time functional imaging.
\nThe excellent tissue resolution of MR imaging provides valuable information on anatomic abnormalities of the rectum and pelvic floor. The dynamic component of MR imaging enables assessment of function and physiology. MR imaging has a high sensitivity of the presence of rectoceles (Figure 10) and rectal prolapse (Figure 10) [9, 11]. Rectoceles are measured and classified on the basis of distance of the anterior or posterior rectal wall from the anal canal axis [9, 11]. A bulge of the rectum that measures less than 2 cm is normal; over 2 cm is abnormal and diagnostic of a rectocele [9, 11, 12]. Rectoceles that protrude up to 3 cm from the normal margin are a significant cause of constipation or incomplete defecation [9, 11, 12]. A rectocele of more than 4 cm is classified as large [9, 11, 12].
\nMid-sagittal SSFSE MR image of the pelvis during evacuation in a patient with constipation shows a large anterior rectocele (arrowhead) and internal intra-rectal prolapse (arrow).
Rectal prolapse may cause constipation due to rectal wall infolding that is induced by chronic straining and fascial disruption [9, 11, 12]. Rectal prolapse can only involve the mucosa or the entire wall thickness [9, 11, 12]. Rectal prolapses may also be internal intra-rectal, internal intra-anal, or external [9, 11, 12]. Although fluoroscopy has been shown to be a highly sensitive modality for the detection of rectal prolapse relative to MR imaging, the superior resolution of MR imaging similarly provides accurate differentiation of mucosa-only prolapse from full-wall-thickness prolapse [9, 11, 12]. Thus MR imaging provides crucial anatomical and functional information for surgical planning and enables accurate discrimination between the subtypes of rectal prolapse [9, 11, 12].
\nSpastic pelvic floor syndrome, or anismus, is caused by paradoxical and involuntary contraction of the puborectalis muscle in the pelvic floor [9, 11]. It results in non-relaxation of the external anal sphincter complex and impairs normal defecation [9, 11]. This causes constipation with prolonged and incomplete defecation [9, 11]. Imaging findings include persistent puborectalis muscular contraction during the strain (Valsalva maneuver) and defecation phases, absence of pelvic floor descent, and an abnormally acute anorectal angle (Figure 11) [9, 11].
\nMid-sagittal gradient echo MR image of the pelvis during evacuation in a patient with chronic constipation show persistent puborectalis muscular contraction (arrow) without expulsion of intra-rectal gel.
CT is the most important imaging modality in the evaluation of patients with known or suspected constipation. It is readily available, performed quickly, allows assessment for potential complications, and permits visualization of extra-colonic structures. The advent of multi-detector CT scanners with improved technical protocols has resulted in faster and more available imaging, particularly in the acute setting. Multi-planar and thin section reconstruction capability may allow for identification of sites of obstruction in the colon and rectum and delineation of colorectal morphology. CT has a reported sensitivity of 96% and specificity of 93% in the identification of constipation. Additional benefits of CT are visualization of complications associated with constipation, particularly stercoral colitis, ischemia, and perforation, and other organ systems for comorbid conditions that may cause constipation [1, 3, 13, 14, 15]. CT is widely used to image adult patients however it is used judiciously in pediatric patients to avoid radiation exposure. If, however, a pediatric patient has constipation that may be secondarily caused by another acute pathology, CT can be of vital importance to diagnosis and management. Radiation dose reduction and modulation may be performed to reduced exposure to pediatric patients.
\nCT has been particularly valuable in the determination of which patients would benefit from conservative medical management or immediate surgical intervention. CT imaging is typically performed using a 64 or 128-section multi-detector row scanner. Each exam is acquired during a single breath hold and in helical mode. Typical exposure settings are 120 kVp, automated tube current modulation with minimum tube current 100–150 mAs and beam pitch, 0.8–1.375. The administration of intravenous (IV) non-ionic contrast material is advised to assess for the presence of a colonic mass, or wall ischemia or inflammation. Exposure settings are set to 100 kVp and automated tube current modulation with minimum tube current is reduced to 80–100 mAs. If IV contrast is administered (contrast-enhanced), a single-phase technique is used with the acquisition of portal venous phase images 70 s after the IV administration of nonionic contrast material that is injected at a rate of 3–5 mL/s. Positive oral contrast material may or may not be used, depending on the indication and urgency or timing of the exam. Multi-planar reconstruction imaging in the coronal and sagittal planes, which are automatically created at the CT technologist’s console, is routinely used. These images may be of great value in not only the diagnosis of constipation but also in the detection of the variety of common and uncommon causes and potential complications.
\nCT may have a substantial and significant impact on the clinical management of the patient by helping to answer major questions: is the patient constipated? Do feces impact the rectum? Are there associated complications of constipation, such as stercoral colitis, ischemia, or perforation? Is the colon obstructed? If the colon is obstructed, can the cause of the constipation be identified, as well as its exact site? CT is particularly useful in the detection of the variety of mechanical causes of constipation.
\nPrimary colonic malignancy is one of the most common mechanical causes [1]. Colonic malignancy is shown on CT as an annular, semi-annular, polypoid, or ulcerated mass that arises from the colon and extends into the lumen or through the wall (Figure 12A–C) [16].
\n(A and B) Axial and coronal images from a contrast-enhanced CT of the abdomen and pelvis of a patient with constipation and bloody bowel movements. There is an enhancing polypoid mass that arises in the cecum and extends into the lumen. (C) The patient then underwent colonoscopy and right colectomy for resection of a colonic adenocarcinoma.
Strictures are another mechanical cause of constipation. The pathophysiological mechanism for the development of a stricture is fibrosis from repeated inflammation or de-vascularization [17]. The main causes of strictures are diverticulitis, ischemia, inflammatory bowel disease, and prior medical therapy like surgery or radiation [17]. CT may display ancillary features of the primary cause of the stricture that may lead to an accurate diagnosis [17]. If the patient has colonic diverticular disease, repeated episodes of diverticulitis may cause a stricture (Figure 13) [15, 18].
\nA patient with several prior episodes of diverticulitis presented with pain and constipation. Coronal image from a contrast-enhanced CT shows a significant amount of feces and fluid in the dilated colon (asterisk) due to sigmoid colonic wall thickening and pericolonic fat stranding in the setting of diverticulosis, compatible with a diverticular stricture.
Multiple and prolonged episodes of inflammation Crohn disease and ulcerative colitis are types of inflammatory bowel disease that may cause a fixed stricture (Figure 14) [15, 19]. Surgical and treatment history may reveal that the fixed stenosis is likely due to adhesive fibrosis from a surgical anastomosis or (Figure 15A and B) [15].
\nCoronal image from a contrast-enhanced CT of a patient with Crohn disease displays a short-segment stricture in the mid-transverse colon (arrow) that results in a short-segment stricture (arrowhead) and upstream constipation.
(A and B) A patient presented with severe constipation and no bowel movements for over 1 week. Axial and coronal images from a contrast-enhanced CT show large feces that distend the cecum and ascending colon (arrow) due to a stricture at the hepatic flexure (circle). The stricture is due to post-surgical fibrosis that developed between the colon and the site of a prior cholecystectomy (circle).
CT plays an invaluable role in the detection of a significant and even fatal complication of constipation that is known as stercoral colitis. Elderly patients, especially those with chronic diseases, are at the highest risk for development of stercoral colitis [3, 13, 14, 15]. Signs and symptoms of stercoral colitis are not specific; however, the most common complaints are constipation and pain [3, 13, 14]. Serologic tests and physical examination are also not specific [3, 13, 14].
\nThe pathophysiology of stercoral colitis begins with constipation. Chronic constipation, without treatment or intervention, may lead to fecal impaction and fecaloma formation [3, 13, 14, 20]. A fecaloma is dehydrated, compacted feces. Impacted feces and fecalomas exert pressure upon the walls of the colon and rectum that in turn impairs vascular perfusion [3, 13, 14, 20]. Hypoperfusion leads to ischemia, infarction, and necrosis of the colon and rectum with consequent perforation [3, 13, 14]. The sigmoid colon is the most common site because: (1) it is the narrowest point in the colon, thereby impeding the transit of dehydrated feces and (2) the rectosigmoid vascular watershed region, known as Sudeck’s point, is susceptible to ischemia [3, 13, 14].
\nRadiography can detect fecal impaction and fecalomas in the colon and rectum however provides no sensitive or specific findings of stercoral colitis [3, 13, 14]. CT is diagnostic of stercoral colitis and its complications and can also exclude alternative causes of pain [3, 13, 14, 15]. The finding that is present in all patients with stercoral colitis is a fecaloma (Figure 16A and B) [3, 13, 14, 15]. Proximal to the fecaloma, the colon may or may not be dilated. The walls of the colon and rectum are asymmetrically thickened to greater than 0.3 cm and my have increased attenuation due to ischemic hemorrhage (Figure 17A–D) [3, 13, 14]. Extra-colorectal findings are inflammatory stranding of the fat that surrounds the colon and rectum and extra-luminal air, which is indicative of a perforation (Figure 18A–C) [3, 13]. Complications of stercoral colitis are perforation, abscess, peritonitis, sepsis, and death; mortality has been reported to approach nearly 50% [3, 13, 14, 15].
\n(A and B) Coronal and sagittal contrast-enhanced CT images of a patient with constipation show fecal impaction in a dilated colon and rectum (arrowhead) with a large, rim-calcified fecaloma (arrow) that causes stercoral colitis.
(A and B) Sagittal and axial non-contrast CT images of a patient with severe abdominal distention and constipation show a dilated colon with a large volume of feces and concentric wall thickening (arrows), indicative of stercoral colitis. (C and D) The majority of the fecaloma was removed in a piecemeal fashion with irrigation and retrieval devices. Images from the colonoscopy show friable, dusky, and erythematous mucosa (arrows), consistent with stercoral colitis and ischemia.
(A and B) Sagittal and axial contrast-enhanced CT images show fecal impaction of the cecum with asymmetric wall thickening (arrowheads) and extraluminal air (arrow) adjacent to a thinned segment of the cecal wall and throughout the peritoneum (arrow), consistent with a perforation. (C) Gross surgical specimen of the resected and perforated cecum, which is filled with feces.
The clinical presentation of a patient with constipation will help govern if imaging is warranted and what is the most appropriate exam to order. Identification of the specific etiologies and associated complications of constipation is facilitated by both anatomic and functional imaging which range from basic radiography to MR imaging. Understanding what information each imaging modality can provide is of paramount importance to order the appropriate test, make an accurate diagnosis, and guide the appropriate management.
\nThe author acknowledges Shaile Philips, M.D. for her contributions and mentorship.
\nThe author declares no conflict of interest.
The author thanks his parents for their support and guidance.
\nSince the publications of Park and Eisenhammer in the 1960s to 1970s, we have gained better understanding on the pathogenesis of cryptoglandular infection leading to perianal abscesses and eventually fistula in ano. With this knowledge, we have moved in strides in producing numerous classifications and treatment options, ranging from minimally invasive techniques to surgical procedures that produces significant disruption to the anorectal anatomy.
Anorectal fistulous abscesses and chronic fistula-in-ano are the same disease. This view has been shared by both Parks and Eisenhammer [1, 2]. We tend to separate both topics and discuss the management separately. However, recent views suggest we should treat it as a same disease, both at different spectrum.
We have yet to achieve a gold standard as recurrence rates and success rates still varies widely across continent. I believe the reasons are:
Lack of comprehensive classification of fistula-in-ano due to a lack of understanding of the natural pattern and progression of the disease.
Lack of unified surgical approach to address different types of fistula-in-ano. Understanding and practices of surgical techniques varies according to institutions and regions.
Chapter Outline:
Revisiting the pathogenesis of cryptoglandular infection.
Relevant updates in anorectal anatomy.
Understanding the natural patterns of cryptoglandular abscesses and fistulas.
Review of practicality of classifications for fistula in ano.
Using natural patterns to classify anorectal abscess and fistula.
Definitive surgical treatment in acute abscess stage.
Emerging concepts in managing cryptoglandular anal fistulas.
In 1961, Park reported his study of 44 specimens of normal anorectal anatomy, and 30 resected specimens from fistula-in-ano surgery. Anal glands were racemose structure of widely ramifying ducts, opening internally via the anal crypts (at dentate line), and extended deep into internal sphincters or ends in the longitudinal layer. They never extend into external sphincter muscles. He concluded that, anal glands provided free channels for infection to pass from the anal lumen deep into the internal sphincter muscles [1]. This observation was echoed by Eisenhammer in 1966, who added that main concentration of large crypts was situated posteriorly, followed by the anterior commissure and last, laterally. Internal orifice of a fistula was always found at the crypt entrance in the pectinate line, at approximately the midlevel of the anal canal [2]. Another study in 1994 by Seow found that 1% of anal glands in fact do penetrate the external sphincter [3]. However, infection arising from external sphincter was never reported.
The term fistulous abscess was used by Eisenhammer; the acute stage represents the abscess, and the chronic stage represents the fistula [2]. Acute abscess progress to a recurrent acute abscess or a chronic infection within the anal glands [1]. Fistula is a granulation tissue tract, develops after abscesses spontaneously rupture or are surgically drainage, where it continues to discharge materials from infected anal gland/ducts. It is kept open by chronic granulomatous inflammation [1, 2].
Pyogenic infections constituting 90% of all cases [1, 2]. Parks noted that 73% of infections occurred at either anterior or posterior midline [1]. Eisenhammer postulated that this intermuscular infection is due to obstructive suppurative adenitis, where causative organism were intestinal bacilli, streptococcus or anaerobes [2].
The cryptoglandular infection pathogenesis remains relevant till present day. From the evidence of early studies, we can conclude that:
Anorectal abscess and fistula are essentially the same disease, both at different end of a spectrum, and therefore should always be treated as a single disease entity.
Origin of infection lies in deep to the internal anal sphincter and longitudinal layer, but not in the external sphincter based on clinical assessments. In the present-day practice, we understand this anatomical region as the intersphincteric space [4].
Majority of the origin of infection lies in either anterior or posterior aspect of anal canal.
Location of the internal opening should be predictable.
90% are pyogenic infection, which can be dealt with appropriate surgery and antibiotics.
Why does complex fistula occur?
Of course, secondary causes of complex fistula-in-ano are not uncommon. It can be due to tuberculosis, Crohn’s disease, perforated colonic diverticular disease or any form of pelvic sepsis [5, 6]. These are beyond the scope of this chapter.
Eisenhammer believes both spectrums of this disease have a pre-determined pattern and is predictable. He wrote: ‘When faulty surgery is performed, natural anatomic barriers become disrupted, new planes of infections opened, leading to complex and complicated conditions’ [6]. Recently, this concept is highlighted again. The pattern of spread should be predictable. Infection of the anorectal region should track in between the anogenital muscular and fascia layers rather than penetrating them, forming abscesses in various anorectal spaces. Anorectal musculature, fascias and spaces are constant. Therefore, the natural patterns of anal fistula should also follow a constant pattern [7].
To understand how cryptoglandular disease manifest as simple or complex disease, we should first discuss the natural patterns of cryptoglandular anorectal abscesses and fistulas.
Quoting Kurihara et al. in 2006, ‘To be able to successfully treat cryptoglandular anorectal abscesses and fistulas, we need to understand the exact anatomy and extension course’ [8]. Secondly, as mentioned before, we need to understand that infection will spread along the least resistant plane, along the planes of anorectal muscles and fascia to reach the respective anorectal spaces [7].
Important anatomical structures are depicted in Figure 1a and b. The internal sphincter and the longitudinal muscle are continuation of the circular and longitudinal smooth muscles of rectum respectively in the anal canal. There are 3 components of external sphincters, subcutaneous, superficial and deep external sphincters, whereas puborectalis is a component of the levator ani [1, 2]. Recent publications suggest that puborectalis is also known to be the same entity as deep external sphincter [7, 9]. Perianal space and Ishio-rectal fossa were described by Parks as the 2 most common spaces for abscess formation [1]. However, his postulation that the source of infection was between internal sphincter and longitudinal muscle was later updated [1].
Coronal view of the anorectal anatomy. Potential space for abscess to form; ISA: ischioanal space, IFL: Infralevator space, SL: Supralevator space, DPA: deep postanal space, PDS: posterior deep space (intersphincteric), IS: intersphincteric space, PRA: perianal space, SP: Superficial perineal space. SIF: septum of ischioanal fossa, TF: transversalis fascia, DPM: deep perineal membrane, ACL: anococcygeal ligament, IAS: internal anal sphincters. EAS: external anal sphincters, components: deep, sup (superficial) and sub (subcutaneous). Deep EAS is interchangeably termed puborectalis muscle. Sagittal view shows significant difference between anterior and posterior perineum. Deep perineal space lies above deep perineal membrane (DPM). Yellow lined arrows show postulated paths for intersphincteric sepsis to traverse the sphincter complex into respective anorectal spaces. Detailed explanation in segment 4.
Internal sphincter circular muscles and longitudinal muscle layer are fused together, and the intersphincteric plane is a potential space between the longitudinal layer and the fascia of striated muscle external sphincters [4, 7] (see Figure 1a and b).
Deep external sphincter overlaps with puborectalis (part of levator ani), and superficial external sphincter overlaps with deep external sphincter, implicating that the external sphincter is not a continuous sheet of striated muscles. The author made a clear distinction between puborectalis and deep external anal sphincter as 2 separate entities, with weak connective tissue between each group [8].
However, other view states that the vertical portion of the levator ani’s striated muscles around the anorectal ring is the puborectalis muscle, interchangeably known as the deep external sphincter [7]. This is supported by previous study by Shafik in 1975 confirming that puborectalis muscle and deep external sphincter are actually fused and functions as a single loop termed the top loop [9].
Both authors stipulate that there is a potential point of weakness between the vertical group and the horizontal group of striated muscles at the level of anorectal ring, allowing infection in the intersphincteric space to spread into the Infralevator space [7, 8].
The emerging terms of deep postanal space, posterior deep space and septum of ischiorectal fossa which will be explained next (refer to segments 4.2 & 4.5) [7, 8, 10, 11].
The anatomy of anterior perineum, especially superficial and deep perineal space are equally important to explain anterior patterns of abscesses and fistulas. Anterior perineum lacks puborectalis/deep external sphincter component. Posteriorly, there is a complex interconnection between intersphincteric space, supralevator space, posterior deep space and deep postanal space. (Shown in Figure 1b) Deep postanal space communicates with both ischioanal space and Infralevator space laterally and deep perineal space anteriorly (refer to segment 4.2) [7].
The 2 most common fistulas described by Park in 1976 were intersphincteric fistula and transphincteric fistula, which accounts for 75% of his series. Eisenhammer in 1966 also reported that 80% in his series were low intermuscular type. Infection arising from anal gland forms suppuration in the intersphincteric space, forming an intersphincteric abscess. Alternatively, it can track along the potential intersphincteric space caudally to the intersphincteric groove or along the subcutaneous external sphincter fibers/septaes to form a perianal abscess. This forms an intersphincteric fistula once it ruptures outwards. However, if it spreads between subcutaneous and superficial external sphincter, it forms a low transphincteric fistula and results in a perianal or ischiorectal abscess. These 2 patterns are the most common findings reported and can occur anteriorly or posteriorly [1, 5, 6, 7, 12].
Posterior perineum divided into 2 compartments, infra-levator space and the clinical ischioanal space by a septum [8]. Abscess in the intra-levator space presents similarly as a clinical supralevator abscess and may not be apparent from external inspection. It can tract anteriorly to the deep perineal space. Infection/abscesses in the clinical ischioanal space is easily diagnosed by clinical examination externally due to inflamed, indurated or fluctuant ischioanal fossa.
There are 3 levels of soft tissue compartments [7].
The lowest level consists of bulbus spongiosus and subcutaneous external sphincter, separated from the mid-level by transversalis fascia. Infection spreads radially in a linear fashion.
The mid-level is termed superficial perineal space containing superficial transverse perineii muscles at the same level as the superficial external sphincter, separated from the deep level by perineal membrane. In males, infection in this space can extend to the scrotal area.
The upper level is the deep perineal space, between the perineal membrane and the levator ani. It communicates posteriorly with the infra-levator space [7]. One should remember that in the deep perineal space, deep external sphincter or puborectalis is absent. Infection can spread between deep perineal space (anterior) and infra-levator space (laterally).
Low or high? This represents the level where infection extends through external sphincter into ischiorectal space. In clinical practice, we define low transphincteric fistula as those involving <1/3 of external sphincter, and high transphincteric fistula if >1/3 involved [12, 13]. Intersphincteric infection can pass through the external sphincter [1, 2, 8, 11], at junctions of each external sphincter portions [8]. If the infection passes through junction between levator ani and deep external sphincter, abscess may present as a Infralevator abscess, and the resulting fistula is a Suprasphincteric type as described by Park [5]. This typically occurs posteriorly and leads to horseshoe pattern (described in 2.2.5). On the other hand, if infection spread at the junction between superficial and deep external sphincter, it will cause ischioanal abscess and a high transphincteric fistula. A low transphincteric fistula results from infection spreading between the junction of superficial and subcutaneous external sphincter.
Infection originating from anterior glands or posterior glands will results in typical patterns. Various authors reported internal openings found mainly at the anterior or posterior anal canal, which corresponds well with infected anal gland/crypt [1, 6].
Anterior gland infection that spreads via transphincteric route have predictable patterns. A low transphincteric pattern will tract along the subcutaneous tissue and below transversalis fascia in a linear fashion. A high transphincteric pattern will tract along the perineal space, in male, it extends into the scrotum. In female, it may result in ano-vaginal fistula or opens around the labia majora or causes perineal abscesses. Anterior horseshoe pattern has also been reported. It extends into the ischioanal space at 11 and 1 o’clock position [2, 6, 7].
Posterior gland infections are as described in 4.3 and 4.5.
Hanley described the horseshoe pattern in detail; Infected anal glands originated from posterior midline of the anal canal, spreading along the longitudinal muscle cranially, passing superior or inferior to deep external sphincter (transphincteric extension) into the space known as deep postanal space. Deep postanal space communicates with both ischiorectal spaces above the surface of the superficial external sphincter. Pus will extend through the plane of least resistance into one or both ischiorectal spaces [10, 11].
In 2006, Kurihara made further anatomical discovery regarding posterior horseshoe pattern. Ischiorectal space is divided into 2 compartments by the septum of ischiorectal space, which starts at the Alcock’s canal to border between puborectalis (part of levator ani) and deep external anal sphincter. This septum is important as the inferior rectal vessels and nerve runs along this fascia layer to penetrate the upper anal canal wall at the deep external sphincter level. At the point where inferior rectal vessels and nerve enters the external sphincter, tissue is loose. Infection spreads upwards along the intersphincteric plane, forms a nidus at the level of deep external sphincter within the intersphincteric space, which is termed as posterior deep space. It can extend via the weak points into either above or below the septum of ischiorectal space, spread either unilaterally or bilaterally to form horseshoe abscesses/fistulas [8]. Both authors however agreed that the internal opening is usually situated at the mid-anal canal posteriorly [8, 10]. Rojanasakul reports that the posterior high transphincteric fistula can occurs at 5 and 7 o’clock position of the anal canal [7].
In rare cases, intersphincteric sepsis tracks cranially, reaching the supralevator space via intersphincteric plane, limited only by the fascia of levator ani (extension of pelvic fascia) [2, 5]. It is unlikely that these collections spread across the levator ani. However, it is possible for the collection to enter the deep postanal space (posteriorly) or infra-levator space via a high transphincteric path or a suprasphincteric path as described above, forming an infra-levator abscess. These 2 are difficult to differentiate clinically, and erroneous drainage of these abscesses may lead to more complex iatrogenic fistulas such as extra-sphincteric fistula or a translevator fistula. Therefore, MRI imaging is advocated if such pattern is suspected [14, 15].
There are numerous classifications of fistula in ano published over the last 4 decades. This chapter will focus on some of the most commonly used classifications to discuss the practicality in clinical scenario.
Park’s classification of fistula-in ano remains popular as the standard terminology used by surgeons. It was published in 1976, based on operative findings of 400 patients over a span of 15 years [5]. The 4 main types are commonly used and reproduced in literatures. However, minimal attention was actually paid to the 14 sub-types in his original report (refer to Figure 2). Park’s classification relied on intra-operative findings as it presented, and focused on the position or configuration of the fistula tract in relation to the external sphincter [5]. There were several disadvantages of this classification.
It does not stratify the complexity of each type of fistula, e.g. low or high fistula, single or multiple tracts.
It does not guide clinicians in locating the source of intersphincteric sepsis and in selecting appropriate surgical treatment.
His clinical findings are recently disputed by several studies using modern imaging, especially the suprasphincteric and extrasphincteric type [8, 14, 16]. Even in 1976, Park described that some cases had difficult anatomy due to fibrosis (recurrence and previous surgery), thus exact anatomy was not entirely ascertained. There was no imaging to guide the findings back then.
Park’s Classification in 1976. 4 main types with its sub-types (diagrams obtained from Park et al, 1976. A classification of fistula-in-ano. Br J Surg. 1976;63[1]:1–12). [
Eisenhammer published his final evaluation (refer to Table 4) based on low or high fistula, location of infection and pattern of spread. It was a useful guide for surgeons to predict the location of internal opening (intersphincteric infection) and course of fistula tract [6]. Eisenhammer stated that his series was mainly from private practice where all the patients presented to him were new cases, thus reporting the actual natural progression and patterns [6]. It is by far the most complete set of classification and focused on patterns of fistula, while stratifying each type by complexity. However, it did not gain popularity due to its’ complex terminologies.
In year 2000, St James University Hospital improved Park’s classification using Magnetic Resonant Imaging (MRI) studies. They analyzed 300 cases and classified fistula to five grades [16]. Essentially an anatomical classification, this classification refined the findings of Parks based on MRI (as shown in Table 1), splitting each of Park’s type I (intersphincteric fistulas) & II (transphincteric fistulas) in two further grades (grade I into I & II and grade II into III & IV) and fused grade III & IV into one grade (grade V) [16]. This classification attempts to stratify fistula into simple or complex, allowing clinicians to judge the use of simple fistulotomy or more complex strategies/expert referrals. However, like Park’s classification, it does not guide clinicians on the location of intersphincteric sepsis nor if the fistula is low or high. Furthermore, recent publications showed that not all intersphincteric fistulas are simple, and not all transphincteric fistulas are complex [7, 12].
St James’s Classification | Description | Park’s Classification |
---|---|---|
Grade 1 | Simple Linear Intersphincteric Fistula | Type 1 – Intersphincteric |
Grade 2 | Intersphincteric Fistula with intersphincteric abscess and secondary fistulous tract | |
Grade 3 | Trans-sphincteric Fistula | Type 2 - Transphincteric |
Grade 4 | Trans-sphincteric Fistula with abscess or secondary track within the ischioanal or ischiorectal fossa | |
Grade 5 | Supralevator & Translevator Disease | Type 3 – Suprasphincteric |
Type 4 - Extrasphincteric |
Comparison of St James Classification and Park’s Classification. The former recognizes the need to stratify Park’s Type 1 and 2 into simple and complex (information extracted from Morris et al, 2000. MR imaging classification of perianal fistulas and its implications for patient management, Radiographics 20 [2000] 623-635 discussion 635-7) [16].
A practical and simple solution was created by Standard Practice Task Force in 2005, classified fistula-in-ano in just two categories-simple and complex [17]. The treatment of complex fistulas posed a high risk to anal continence and in simple fistulas, fistulotomy could be done safely without any risk of incontinence. The latter usually involved less than one-third of sphincter complex. Fistulotomy is not recommended in complex fistulas.
However, a study in 2017 showed that 32.1% (93/290) of complex fistulas were amenable to fistulotomy [12]. Simple and complex classification was shown to overestimate complexity of fistula. Furthermore, it was not particularly useful for clinicians in differentiating different types or patterns of complexity and determining the specific management.
The most recent classification was introduced in 2017 and validated in 2020 with over 848 patients using combination of MRI study and intra-operative findings [12, 18]. This classification provided comprehensive and detailed grouping of anal fistula into 5 grades, from simple to complex grading (Table 2). In general, complexity was determined by low or high fistula, presence of multiple secondary tracts or collections. Intersphincteric and transphincteric fistulas were both recognized as simple if the fistula is low and safe for fistulotomy. This classification allows stratification of fistula-in-ano in a practical manner to guide their management strategies. Grade 1 and 2 fistulas were reported as safe to be treated with fistulotomy, whereas grade 3 to 5 requires more complex surgical strategy or expert referral (refer to Table 2) [12]. This method of stratification was validated to be safe. Following the Garg’s new classification, patients underwent fistulotomy did not show significant changes in continence score post operatively [18]. However, this grading method relies heavily on MRI, which is not readily available in all institutions. Furthermore, there are many subclassifications to remember and challenging complex type such as suprasphincteric, supralevator and extrasphincteric types, were group into a single category even though each have unique patterns.
Grade 1 | Low* Fistula with single branch | SIMPLE ¥ |
Intersphincteric or Transphincteric | ||
Grade 2 | Low* Fistula with multiple tracts, abscess or horseshoe. | |
Intersphincteric or Transphincteric | ||
Grade 3 | High* Transphincteric with single branch | |
Anterior fistula in female | ||
May have: Impaired continence, Crohn’s disease or Previous radiation | ||
Grade 4 | High* Transphincteric with | |
Multiple tracts, Abscess, Horseshoe. | ||
Grade 5 | High* Transphincteric with Supralevator tract | |
Or Suprasphincteric | ||
Or Extrasphincteric |
Garg’s New Classification of Anal Fistulas (information extracted from Garg [18]).
Low transphincteric: <1/3 of external sphincter involved. High transphincteric: > 1/3 of external sphincter involved.
Grade 1: Fistulotomy should be possible in almost all these fistulas (>95%). Grade 2: Fistulotomy should be possible in majority of these fistulas (>90%).
A useful classification allows clinicians:
To categorize various subsets or presentations of a disease for better understanding.
Stratification of a disease according to severity or complexity.
To guide clinicians in treatment strategy and prognostication.
In general, most of the classifications above do not fulfill all 3 criteria above. Garg’s classification was a significant improvement in categorizing, stratification and suggested treatment options for each grade. However, when faced with complex fistulas, there is still a general lack of understanding of its pathogenesis and optimal surgical treatment. This author believes, the step forward is to provide a more comprehensive treatment algorithm/guideline based on knowledge of natural patterns and progressions. To achieve this, the author believes classification based on natural patterns of cryptoglandular abscess and fistula will provide further insight.
The new idea. Most classifications focus on anatomical configurations of fistula. It is possible to classify anorectal abscesses and fistula-in-ano based on natural patterns. This type of classification is beneficial as:
It helps clinician to understand the pathogenesis better, leading to a better understanding of different types and patterns of complex fistulas.
It helps clinician to predict the source of infected anal glands and intersphincteric sepsis, and the same time identify secondary extensions and external tracts.
This author postulate that it may reduce clinicians’ reliance on imaging modalities.
Eisenhammer produced a classification method and later modified it in 1978 on his final evaluation of 800 patients over a span of 25 years. In general, the basis of his classification lied on low or high fistula/abscess, the position of the infected anal crypt (anterior or posterior), confined to intermuscular space (intersphincteric space) or spread to ischiorectal space [6]. However, it was not commonly utilized over the next few decades.
Rojanasakul proposed to classify the Natural Pattern of Anal Abscess and Fistula. It is effectively summarized into 5 main patterns and each pattern predicts the location of internal opening (refer to Table 3). This is paramount for surgeons to locate the offending anal gland/crypt for optimal treatment. Almost all patterns can be summarized by a simple classification of 5 patterns (refer to Figure 3) [7].
Pattern | Internal opening (& Intersphincteric tract) | Proportion |
---|---|---|
1. Intersphincteric pattern | Internal opening: any direction | 3.8% |
2. Low transphincteric pattern | Internal opening: any direction, most common anterior and posterior | 26.9% |
3. Anterior high transphincteric pattern | Internal opening: anterior. 11, 12 or 1 o’clock position | 27.9% |
4. Posterior high transphincteric pattern | Internal opening: posterior Common: posterior midline Less common: 5 and 7 o’clock position | 31.7% |
5. High intersphincteric pattern | Internal opening: posterior Common to occur concurrently with posterior high transphincteric fistula (horseshoe fistula) | 9.6% |
Summary of natural patterns of anorectal abscesses and fistulas with predicted internal opening, intersphincteric tract and proportion (information extracted with permission from Rojanasakul & Tsang, 2021. Emerging Concepts in Classification of Anal Fistulae. Pelvic Floor Disorders, Springer) [7].
Diagrammatic illustration of 5 types of natural patterns. SLA: Supralevator abscess. DPA: Deep post-anal abscess. Red dotted line represents the course of horseshoe pattern due to connection between deep post-anal space and ischioanal space/Infralevator space.
Type 4 and 5 can occur in combination. This is often complex and confusing to clinicians as it may present with a supralevator abscess concurrently with bilateral horseshoe or ischioanal abscesses (Shown in Figure 3). The key to managing this combination type is to address both the high intersphincteric tract and the high transphincteric tract with combination of surgical techniques (will be described in segment 8). When we compare both Eisenhammer’s finding to this new classification of natural patterns, we find that all of the previously described types can be simplified into these 5 main patterns (refer to Table 4). Clinicians should be mindful that it is possible for 2 patterns to occur concurrently [7].
Comparing current classification of natural patterns with Eisenhammer’s updated description and classification in 1978 [6, 7].
Infection occurs in the clinical ischiorectal space.
Infection occurs in the infra-levator space.
Ω π μAnterior high transphincteric pattern can present as bilateral horseshoe, anovulvar tract or unilateral horseshoe. Bilateral anterior horseshoe pattern tends to have a lower internal opening compared to unilateral anterior horseshoe pattern [2, 6]. However, no other studies reported similar findings.
Park attributes extrasphincteric fistula to the following causes: secondary to a transphincteric fistula, trauma, specific anorectal disease and pelvic inflammation [5]. Eisenhammer’s stated in both his initial series and final evaluation that extrasphincteric fistula was due to either iatrogenic probing or secondary causes such as pelvic sepsis, colonic diverticular diseases or inflammatory bowel disease [2, 6]. Garg’s evaluation of more than 400 patients with anal fistula using MRI reported that there were no cases of extrasphincteric fistula in his series [12]. The most probable cause of extrasphincteric fistula: It is a combination of posterior high transphincteric fistula and high intersphincteric fistula situated posteriorly, resulting in both supra-levator collection and Infralevator collection. Incorrect drainage or probing of either can lead to a communication between the two collections across the levator ani [7]. Therefore, it is reasonable to conclude that extrasphincteric fistula does not fit into the natural pattern of cryptoglandular infection. Its finding should alert surgeons of possibility of previous erroneous surgery or secondary sepsis originating from pelvis/abdomen [6].
Understanding the pathogenesis and natural pattern helps in management of fistula-in-ano. Lessons from early publications showed that successful treatment of fistula-in-ano lies on the ability of surgeons to eradicate the source of infection, which is the infected anal crypt/gland and the intersphincteric abscess/tract [1, 2, 10, 19]. Recent publications further emphasized on eradicating secondary tracts or abscesses to prevent recurrences [15, 20, 21]. Therefore, objective clinical assessment should assist clinicians to:
Identify the internal opening & intersphincteric tract/abscess.
Identify the location of anorectal space involved.
Identify the external tract and secondary branches.
Ascertain the level of sphincter involved.
In the author’s view, using the knowledge and classification of the Natural Patterns of Anal Abscess and Fistula [7], the above information can be actively sought after using a combination of clinical assessment and imaging modalities.
In cases of acute abscess, clinical examination generally elicits tenderness and fluctuation around perianal or ischioanal fossa. However, detailed assessment is usually informative with sedation, local or regional anesthesia. In high intersphincteric abscesses or Infralevator abscesses, tenderness is elicited on digital rectal examination at the anorectal ring. Examination under anesthesia may reveal pus discharge from internal opening upon insertion of anoscope. Perianal abscess is typical of type 1 (Intersphincteric) and type 2 (Low Transphincteric) patterns, and internal opening usually corresponds with the location of abscess. Ischioanal fossa abscess is the usual presentation of type 3 and 4 (high transphincteric) patterns. However, it should also be remembered that type 4 pattern produces Infralevator abscess, where internal opening is almost always posterior. Type 5 pattern produces high intersphincteric abscess and internal opening is usually posterior [6, 7].
In cases of chronic fistula, location of external opening and course of fistula tract should direct clinicians to the possible patterns. Low fistulas are clinically palpable as thickened fibrous cord extending from the external opening towards the infected anal crypt (internal opening). In high fistulas, tracts are usually not palpable subcutaneously. Digital examination may reveal chronic induration over the anorectal ring adjacent to lateral wall of rectum. External tracts usually runs deep and parallel with the anal canal on probing [6].
In cases where internal opening is not apparent, there are several techniques described to facilitate the identification of internal openings [6, 15].
Hard, board like changes to the deep surface of the internal sphincter usually represents the location of infected anal crypt.
Offending anal crypt retracts into a funnel on pulling the external tract.
Palpation of cord-like fibrous tract.
Internal opening probing: using hook or right-angled blunt tip forceps.
Gentle probing from external sinus: using small sized urethral catheter. Lacrimal probe is not advisable as it may cause false tracts.
Injection of dye (methylene blue solution) or water via external sinus.
Sensitivity of clinical examination in detecting the primary fistula tract is 68.7%, followed by 62.1% for secondary extension, and 59.7% for localizing internal opening [22]. Therefore, imaging is required as adjunct.
Magnetic resonant imaging (MRI) and Endoanal ultrasound (EAUS) are the 2 most reliable imaging modality to delineate anorectal abscess and fistula. Conventionally, both modalities are equally sensitive in detecting anal fistula, but MRI has slightly superior specificity compared to EAUS [23]. MRI is not readily available in all institutions, whereas EAUS is operator dependant and requires significant learning curve.
Kim et al. in 2009 reported that 3 dimensional endoanal ultrasound is the preferred method, and use of hydrogen peroxide contrast may increase the detection rate of anal fistula. Sensitivity in detecting primary fistula tract is 84.4%, 81.8% for secondary extension and 84.2% for localizing the internal opening [22].
Recently, the interest in MRI has surged, in line with renewed efforts from various institutions to produce new classifications [16, 18]. With the availability of MRI scan, the fistula could be assessed in all three dimensions (axial, coronal and sagittal) [14]. The sensitivity and specificity of MRI in diagnosing fistula tracts were 98.8 and 99.7%, and in identifying internal opening were 97.7 and 98.6% respectively [14]. In addition, MRI is able to reclassify simple fistula based on clinical assessment to complex fistula, as it has the extra benefit of detecting additional secondary tracts, horseshoe tracts and supralevator extensions [18].
Clinical assessment and imaging adjunct helps clinicians to identify internal opening and intersphincteric tract/abscess, location of abscess, external tracts and secondary tracts. It also helps to define low and high fistula. This information will assist clinicians to recognize the type of anal fistula/abscess, thus allowing stratification and planning for appropriate surgical treatment. Surgical treatment will be discussed in the next segments.
Eisenhammer wrote: ‘
Major guidelines recommend that immediate fistulotomy should be undertaken only by experienced surgeons, and a more conservative practice of simple abscess drainage in most circumstances is safest. Fistulotomy should only be done in low or simple fistulas [13, 25, 26]. This approach is known to be beneficial for 2 reasons: 1) Simple incision and drainage procedure, especially as an office procedure, allows quick return of function and daily living, thus avoiding prolong wound healing and hospital stay [2, 27]. 2) Less experienced surgeons may be confused with the exact anatomy of the fistula, or may cause iatrogenic injury and incorrect fistulotomy [6].
However, in the author’s view, definitive surgery during the acute abscess stage has its advantage. Sharing Eisenhammer’s view, the ideal management should be during the acute abscess stage [6]. Treating the fistula during acute abscess stage will reduce the number of chronic fistula formation [19]. A meta-analysis showed that definitive treatment leads to a risk reduction of 83% in recurrent fistula [24]. Furthermore, this is cost effective for health care facilities in general as the burden of treating chronic fistula is greatly reduced by reducing the need for re-operations.
Conventionally, several techniques were described in treating fistula during acute abscess stage. For perianal and ischioanal abscesses with identifiable fistula tract, fistulotomy, fistulectomy and cutting seton were used [19, 24, 25, 26]. Internal sphincterotomy was reported for intersphincteric abscess [6, 13]. Oliver reports performing immediate fistulotomy only for low transphincteric, intersphincteric and subcutaneous type, with recurrence rate of 5% [28].
A meta-analysis in 2006 analyzed 5 studies with a total of 405 patients showed that internal opening is not found in 10–17% of cases [24]. Inability to locate internal opening leads to higher recurrence rate as the source of infected anal crypt is not dealt with. Recurrence rate increased from 5–29% when internal opening was not found [28]. Imaging modalities are not readily available in cases of acute abscess.
The same meta-analysis reported that sphincter-cutting procedures like fistulotomy and cutting seton during acute abscess is associated with 2-fold increase of risk of fecal incontinence to flatus and soiling. Severe incontinence rate was reported up ranging from 0 to 40%, although sample sizes for most studies were small [24].
The principles of treating acute fistulous abscess were laid down by McElwain:
Identification and excision of offending anal crypt [19] – position of infected gland and internal opening
Laying open the intermuscular abscess cavity [19] – drainage of intersphincteric space
Create a superficial external drainage for abscess beyond the external sphincter [19] – drainage of extrasphincteric abscesses
This author adds another 2 important principles:
Keeping wound open for drainage and to allow secondary healing.
Preservation of continence as best as possible.
In line with sphincter preservation as an important principle, a recent prospective study showed promising results utilizing sphincter preserving techniques for drainage and definitive treatment of fistulous anorectal abscess [29]. 86 patients with anorectal abscesses were operated by a single surgeon with intention of definitive single stage surgery and preservation of sphincter muscles. Using Rojanasakul’s Natural Patterns of Anorectal Abscess and Fistula classification as guide, this study proposes 2 important steps: 1) Drainage of the perianal abscess at its most bulging point, 2) Exploration of the intersphincteric space to locate internal opening and intersphincteric tract/abscess. Internal opening was found in 95% of cases and intersphincteric tract was found in 77% of cases. Intersphincteric tract is treated with ligation as per LIFT procedure [4], whereas intersphincteric abscess were drained with suture closure of internal opening. Intersphincteric exploration wound is loosely closed with tube drains to promote drainage and secondary healing. This method reported overall healing rate of 83%, where the best results is obtained if intersphincteric tract is well formed. There were no cases of post-op incontinence. The remaining 17% non-healing group went on to elective surgery for definitive surgery of chronic fistula [29].
It is well known that in patients with anorectal abscesses undergoing simple drainage, 2/3 will progress to chronic fistula [27]. Definitive treatment of fistula may reduce the incidence of chronic fistula to an estimated below 30% based on recent evidence [28, 29]. With emerging sphincter preserving approaches, guided by our understanding of patterns of infection spread and imaging modalities, we are better equipped to approach acute fistulous abscesses with intention of single stage surgery.
Principle of surgical treatment of chronic fistula-in-ano should include the following:
Identification and removal of the source of sepsis in the intersphincteric space [1, 4, 6, 30].
Eradication of external and secondary tracts or abscesses [15, 20].
Maintaining the intersphincteric space open to heal by secondary intention [15].
Preservation of continence as best as possible [13, 25, 26].
An ideal surgical procedure should fulfill all 4 criteria above. Various surgical techniques have been described in literatures, ranging from sphincter cutting procedures to minimally disruptive biomaterials or novel techniques. In this segment, the author attempts to classify various surgical procedures into categories, thereby assessing its suitability for specific fistula types and adherence to the above principles.
Fistulotomy is the oldest, simplest, and most widely used procedure for anal fistulae. Most major guidelines recommend fistulotomy as a suitable and safe procedure for simple or low fistula [13, 25, 26]. This procedure involves laying open the entire fistula tract, together with the sphincter muscles it traverses, with adequate curettage to remove all granulation tissue tract [13, 31]. Marsupialization of the edges appears to speed up wound healing and reduces post-op pain and bleeding, but reported benefits were not significant [13]. Success rate is more than 90%, but incontinence rate is reported as high as 28% in elective setting [31]. According to Garg et al. in 2020, fistulotomy performed on low intersphincteric and low transphincteric fistulas (Garg’s Classification grade 1 & 2) is safe. Post-operative mean continence score increased from 0.044 to 0.135, without reaching statistical significance. Low fistula is defined as involvement of less than 1/3 of external sphincter [18]. Failure of treatment or recurrence is associated with inappropriate selection of patients with high fistula or multiple tracts [31].
Internal sphincterotomy was first reported by Eisenhammer in 1966 to treat low intermuscular fistula (low intersphincteric type) which accounted for majority of cases in his series [2]. The principle is similar to fistulotomy, where the only difference is only lower half of internal sphincter muscles were laid open to eradicate intersphincteric sepsis. This technique gradually became synonymous with fistulotomy in various literatures as later studies showed that low intersphincteric type is far less common than low transphincteric type [7, 12]. In recent decade, ASCRS Practice Parameters introduced it as a treatment for intersphincteric fistulous abscess [13]. This technique is suitable for low intersphincteric type and does not cause incontinence [6].
Surgeons generally try to avoid sphincter cutting techniques. Ligation of Intersphincteric Tract (LIFT) procedure avoids sphincter cutting, using a small incision to explore the intersphincteric space to ligate and excise the intersphincteric tract [4] or to drain intersphincteric abscess [29]. Additional procedure in combination with LIFT such as closure of internal opening, excision of external tract and bioprosthetic mesh have been reported to improve outcomes [32]. A recent report from the original birthplace of LIFT procedure reported 10 year overall primary healing rate of 87.65%, and overall healing rate after re-operation was 99.2%. True recurrences were due to recanalization as a result of incorrect identification of intersphincteric tract. However, majority of recurrences were due to infection in the intersphincteric wound, leading to intersphincteric fistula which was easily treated by fistulotomy [20]. Other reports cited Crohn’s disease, complex multiple fistulas and horseshoe pattern as a common cause of recurrences [33], stressing the importance of identification of secondary tracts and abscesses. In the author’s view, LIFT procedure is best combined with additional curettage, drainage or excision of external fistula tracts/abscess. Recently, the original author reported slight modification where LIFT incision was loosely approximated and tube drain inserted to reduce intersphincteric space infection and promote secondary healing [29]. A recent meta-analysis and systematic review reported overall pooled success rate of 76.5% and incontinence rate of 1.4% [21].
Excision of fistula with immediate sphincter reconstruction is an alternative to reduce the risk of incontinence, at the same time completely eradicate intersphincteric and secondary tracts. It is suitable for both low and high transphincteric fistula. Procedure is similar as described in 8.1, with additional sphincter repair to restore continuity. Term as Fistulotomy or fistulectomy with primary sphincteroplasty (FIPS), Ratto reports 93.2% overall success rate, with a low morbidity rate [33]. Overall postoperative worsening continence rate was 12.4% mainly post-defecation soiling, without significant changes in anorectal manometry parameters [33]. In general, this technique produces higher success rate compared to LIFT procedure, albeit variations of techniques and terms used across institutions [34]. Incontinence is still a major concern, despite being much lower than fistulotomy alone. It is recommended in the German’s S3 guideline but not in other major guidelines [26]. In the author’s recent experience, this procedure produces excellent outcome in both low and high transphincteric chronic fistula, and extrasphincteric secondary (branching) tracts can be excised or curetted concurrently. However, in acute abscess stage, initial seton drainage is preferred prior to FIPS to reduce the risk of breakdown of sphincter repair [34].
Loose draining seton allows initial control of sepsis prior to definitive surgery to improves success rate. German S3 guideline used the term fibrosing seton [26]. It allows drainage of abscess and forms a thick fibrous fistula tract, which can be dealt with easily on the next elective surgery. Draining seton before LIFT shows no added benefits [32]. However, seton before fistulotomy and sphincter reconstruction showed benefits in downstaging high transphincteric to low transphincteric type [34]. From personal experiences, seton drainage can also be utilized to drain ischioanal/Infralevator collections with multiple external openings after debridement or curettage to prevent extensive wounds in the perineum.
Many sphincter saving biomaterials and novel techniques surfaced in the last 4 decades to deal with complex fistula with wide variation of success rates across continents. Among those are anal fistula plug [35, 36], fibrin glue [26], laser procedures [37], Video Assisted Anal Fistula Tract Treatment (VAAFT) [38] and endoscopic clips (OTSC) [39]. Across the board, none of these procedures have reported very high success rate. This is likely due to the fact that most procedures, in their attempt to avoid cutting sphincters, only focus on the closure of internal opening and/or the fistula tract, but do not eradicate the intersphincteric sepsis and its secondary tracts. The author’s opinion is that these procedures are highly specialized and are often based on selected specialized institutions. Therefore, usage of these techniques should be reserved to experts of the respective fields.
Garg described an improved procedure in 2017 for high fistulas termed Transanal Opening of the Intersphincteric Space (TROPIS) [30]. High intersphincteric tracts and abscesses are typically difficult to reach via intersphincteric approach or conventional probing from external opening, and usually branching. TROPIS procedure allows lay open and drainage of these tracts into the anal canal, thus eradicating septic nidus at the high intersphincteric plane, which is usually posterior and was termed as the posterior deep space in the previous segment 4.5. This is done through the internal opening and external sphincter is not cut. The external branching tracts in the ischiorectal fossa were curetted. The space is left open for secondary healing. In the initial prospective cohort of 61 patients, success rate was 84.6% with no significant changes in continence score. The series consist of a mixture of high transphincteric type (anterior and posterior) and high intersphincteric type [30]. Incision on the internal sphincter is shown to be safe without worsening incontinence [2, 30, 40]. In author’s personal experience, TROPIS procedure is an excellent approach for high intersphincteric type and posterior high transphincteric type, especially if transphincteric fistula is located at the puborectalis level. However, like LIFT procedure, combination with drainage, curettage or excision of external tracts is necessary to reduce recurrences.
To achieve good outcomes for anal fistula surgery, the author concludes that; 1) Understanding of type and natural patterns of fistula is extremely important, 2) The 4 principles of surgical treatment should be adhered to as closely as possible, and 3) No one surgical technique is suitable for all types of fistula. Therefore, selecting the appropriate procedure is important and to our best knowledge, no guidelines or classifications so far outlines a complete treatment algorithm especially on complex fistulas. Based on this review of evidence and best clinical judgment of the author, Table 5 below attempts to summarize reasonable treatment options available for different fistula types to guide surgeons, where combination of procedures, additional procedures or modification of procedures is preferred over single modality (refer to Table 5).
Type of pattern | Suitable procedure | Intersphincteric sepsis eradication | Eradication of external and secondary tracts/abscesses | Healing by secondary intention | Preservation of continence |
---|---|---|---|---|---|
1. Low Intersphincteric | Fistulotomy or Internal Sphincterotomy | Yes | NA | Yes | Yes |
FIPS | Yes | NA | NA | Yes | |
2. Low Transphincteric | Fistulotomy | Yes | Yes | Yes | Unpredictable |
FIPS | Yes | Yes | NA | Yes | |
LIFT | Yes | Yes | Yes | ||
3. Anterior High Transphincteric | FIPS* | Yes | Yes | NA | Yes |
LIFT | Yes | Yes | |||
4. Posterior High Transphincteric | FIPS | Yes | Yes | NA | Yes |
LIFT | Yes | Yes | |||
TROPIS | Yes | Yes | Yes | ||
5. High Intersphincteric | TROPIS | Yes | Yes | Yes | Yes |
6. Combination type 4 & 5 | Combination: TROPIS + | Yes | Yes | Yes | |
Staged approach. TROPIS, draining seton and delayed LIFT or FIPS | Yes | Yes | Yes | Yes |
Summary of appropriate surgical treatment for different types of fistula pattern based on the principles of surgical treatment. No single procedure is 100% successful, therefore our clinical judgment is important in deciding on additional procedures, combination, staged approaches or modification to achieve our goal.
Caution in performing FIPS in anterior transphincteric fistula, especially in female patients where external sphincter is thin, lack of support anteriorly and risk injuring perineal body.
CED: Short for closure of external sphincter defect. After lay open of intersphincteric tracts and abscesses, an attempt is made to close the defect where transphincteric tract traverses the external sphincter. This can be done transanally or via external opening wound.
Mod: Modification by loosely approximate incision with tube drains to allow drainage and secondary healing of intersphincteric wound [29].
Add: Additional procedures includes drainage of ischioanal/Infralevator abscess, curettage or excision of external tracts, insertion of drains to the ischiorectal space [15, 29, 30].
Seton: Use of loose draining seton for drainage, induce fibrosis to form thickened tract and allows downgrading of high to low transphincteric fistula [34].
NA: Not applicable.
Revisiting the anatomy and pathogenesis facilitates us to understand the natural patterns of anorectal abscess and fistula. With this new idea, we are able to classify and stratify this disease according to level of complexity and sphincter involvement, thus selecting the appropriate tool to manage it. Definitive treatment in acute abscess stage is feasible if the principles are followed. Surgical options and strategies should be carefully selected to suite each pattern, while adhering to the principles of surgical treatment. Challenges in managing cryptoglandular fistula-in-ano are summarized in Appendix (Table 6). The proposed solution is carefully selected from the current review of evidence and the experience of a high-volume tertiary centre.
The author would like to acknowledge Dr. Khairul Mustaqim Mazlan, Hospital Universiti Sains Malaysia (Kota Bharu) for contributing the graphics and figures in this paper, and Dr. Ng Hui Been, Hospital Raja Pemaisuri Bainun (Ipoh) for her contribution in prove reading and language editing.
The author declares no conflict of interest.
Challenges | Complications | Proposed solution |
---|---|---|
i. Confusion in classification | • Wrong diagnosis | Adapting classifications that allows clear delineation of patterns, stratification of severity and guides management [7, 12] |
• Wrong stratification into simple or complex | ||
ii. Incorrect delineation of pattern | • Wrong procedure | Combination of clinical assessment and imaging modalities: MRI, EAUS |
• Risk of recurrence and incontinence | ||
iii. Acute abscess | • Develop chronic fistula | McElwain’s principle [19] |
Consider intersphincteric exploration [29] | ||
iv. High fistula | • Difficult to delineate | Role of MRI [15] |
• High risk of incontinence if treated with sphincter cutting surgery | TROPIS procedure [30] | |
v. Multiple secondary tracts and abscesses | • Risk of recurrence if not completely treated | Role of MRI and natural patterns classification [7, 14] |
• Technically more demanding | Additional procedures: drainage, curettage, excision. | |
vi. Internal opening not found | • Risk of recurrence | Combination of clinical assessment and imaging modalities: MRI, EAUS |
Attempt closure of internal opening at its predicted site [29]. |
Challenges in managing fistula-in-ano, with summary of its complications and proposed solutions.
Special gratitude to my beloved wife, Dr. Ingrid Ting for her unwavering support in the process of completing this writing.
"Open access contributes to scientific excellence and integrity. It opens up research results to wider analysis. It allows research results to be reused for new discoveries. And it enables the multi-disciplinary research that is needed to solve global 21st century problems. Open access connects science with society. It allows the public to engage with research. To go behind the headlines. And look at the scientific evidence. And it enables policy makers to draw on innovative solutions to societal challenges".
\n\nCarlos Moedas, the European Commissioner for Research Science and Innovation at the STM Annual Frankfurt Conference, October 2016.
",metaTitle:"About Open Access",metaDescription:"Open access contributes to scientific excellence and integrity. It opens up research results to wider analysis. It allows research results to be reused for new discoveries. And it enables the multi-disciplinary research that is needed to solve global 21st century problems. Open access connects science with society. It allows the public to engage with research. To go behind the headlines. And look at the scientific evidence. And it enables policy makers to draw on innovative solutions to societal challenges.\n\nCarlos Moedas, the European Commissioner for Research Science and Innovation at the STM Annual Frankfurt Conference, October 2016.",metaKeywords:null,canonicalURL:"about-open-access",contentRaw:'[{"type":"htmlEditorComponent","content":"The Open Access publishing movement started in the early 2000s when academic leaders from around the world participated in the formation of the Budapest Initiative. They developed recommendations for an Open Access publishing process, “which has worked for the past decade to provide the public with unrestricted, free access to scholarly research—much of which is publicly funded. Making the research publicly available to everyone—free of charge and without most copyright and licensing restrictions—will accelerate scientific research efforts and allow authors to reach a larger number of readers” (reference: http://www.budapestopenaccessinitiative.org)
\\n\\nIntechOpen’s co-founders, both scientists themselves, created the company while undertaking research in robotics at Vienna University. Their goal was to spread research freely “for scientists, by scientists’ to the rest of the world via the Open Access publishing model. The company soon became a signatory of the Budapest Initiative, which currently has more than 1000 supporting organizations worldwide, ranging from universities to funders.
\\n\\nAt IntechOpen today, we are still as committed to working with organizations and people who care about scientific discovery, to putting the academic needs of the scientific community first, and to providing an Open Access environment where scientists can maximize their contribution to scientific advancement. By opening up access to the world’s scientific research articles and book chapters, we aim to facilitate greater opportunity for collaboration, scientific discovery and progress. We subscribe wholeheartedly to the Open Access definition:
\\n\\n“By “open access” to [peer-reviewed research literature], we mean its free availability on the public internet, permitting any users to read, download, copy, distribute, print, search, or link to the full texts of these articles, crawl them for indexing, pass them as data to software, or use them for any other lawful purpose, without financial, legal, or technical barriers other than those inseparable from gaining access to the internet itself. The only constraint on reproduction and distribution, and the only role for copyright in this domain, should be to give authors control over the integrity of their work and the right to be properly acknowledged and cited” (reference: http://www.budapestopenaccessinitiative.org)
\\n\\nOAI-PMH
\\n\\nAs a firm believer in the wider dissemination of knowledge, IntechOpen supports the Open Access Initiative Protocol for Metadata Harvesting (OAI-PMH Version 2.0). Read more
\\n\\nLicense
\\n\\nBook chapters published in edited volumes are distributed under the Creative Commons Attribution 3.0 Unported License (CC BY 3.0). IntechOpen upholds a very flexible Copyright Policy. There is no copyright transfer to the publisher and Authors retain exclusive copyright to their work. All Monographs/Compacts are distributed under the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). Read more
\\n\\nPeer Review Policies
\\n\\nAll scientific works are Peer Reviewed prior to publishing. Read more
\\n\\nOA Publishing Fees
\\n\\nThe Open Access publishing model employed by IntechOpen eliminates subscription charges and pay-per-view fees, enabling readers to access research at no cost. In order to sustain operations and keep our publications freely accessible we levy an Open Access Publishing Fee for manuscripts, which helps us cover the costs of editorial work and the production of books. Read more
\\n\\nDigital Archiving Policy
\\n\\nIntechOpen is committed to ensuring the long-term preservation and the availability of all scholarly research we publish. We employ a variety of means to enable us to deliver on our commitments to the scientific community. Apart from preservation by the Croatian National Library (for publications prior to April 18, 2018) and the British Library (for publications after April 18, 2018), our entire catalogue is preserved in the CLOCKSS archive.
\\n\\nOpen Science is transparent and accessible knowledge that is shared and developed through collaborative networks.
\\n\\nOpen Science is about increased rigour, accountability, and reproducibility for research. It is based on the principles of inclusion, fairness, equity, and sharing, and ultimately seeks to change the way research is done, who is involved and how it is valued. It aims to make research more open to participation, review/refutation, improvement and (re)use for the world to benefit.
\\n\\nOpen Science refers to doing traditional science with more transparency involved at various stages, for example by openly sharing code and data. It implies a growing set of practices - within different disciplines - aiming at:
\\n\\nWe aim at improving the quality and availability of scholarly communication by promoting and practicing:
\\n\\n\\n"}]'},components:[{type:"htmlEditorComponent",content:'
The Open Access publishing movement started in the early 2000s when academic leaders from around the world participated in the formation of the Budapest Initiative. They developed recommendations for an Open Access publishing process, “which has worked for the past decade to provide the public with unrestricted, free access to scholarly research—much of which is publicly funded. Making the research publicly available to everyone—free of charge and without most copyright and licensing restrictions—will accelerate scientific research efforts and allow authors to reach a larger number of readers” (reference: http://www.budapestopenaccessinitiative.org)
\n\nIntechOpen’s co-founders, both scientists themselves, created the company while undertaking research in robotics at Vienna University. Their goal was to spread research freely “for scientists, by scientists’ to the rest of the world via the Open Access publishing model. The company soon became a signatory of the Budapest Initiative, which currently has more than 1000 supporting organizations worldwide, ranging from universities to funders.
\n\nAt IntechOpen today, we are still as committed to working with organizations and people who care about scientific discovery, to putting the academic needs of the scientific community first, and to providing an Open Access environment where scientists can maximize their contribution to scientific advancement. By opening up access to the world’s scientific research articles and book chapters, we aim to facilitate greater opportunity for collaboration, scientific discovery and progress. We subscribe wholeheartedly to the Open Access definition:
\n\n“By “open access” to [peer-reviewed research literature], we mean its free availability on the public internet, permitting any users to read, download, copy, distribute, print, search, or link to the full texts of these articles, crawl them for indexing, pass them as data to software, or use them for any other lawful purpose, without financial, legal, or technical barriers other than those inseparable from gaining access to the internet itself. The only constraint on reproduction and distribution, and the only role for copyright in this domain, should be to give authors control over the integrity of their work and the right to be properly acknowledged and cited” (reference: http://www.budapestopenaccessinitiative.org)
\n\nOAI-PMH
\n\nAs a firm believer in the wider dissemination of knowledge, IntechOpen supports the Open Access Initiative Protocol for Metadata Harvesting (OAI-PMH Version 2.0). Read more
\n\nLicense
\n\nBook chapters published in edited volumes are distributed under the Creative Commons Attribution 3.0 Unported License (CC BY 3.0). IntechOpen upholds a very flexible Copyright Policy. There is no copyright transfer to the publisher and Authors retain exclusive copyright to their work. All Monographs/Compacts are distributed under the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). Read more
\n\nPeer Review Policies
\n\nAll scientific works are Peer Reviewed prior to publishing. Read more
\n\nOA Publishing Fees
\n\nThe Open Access publishing model employed by IntechOpen eliminates subscription charges and pay-per-view fees, enabling readers to access research at no cost. In order to sustain operations and keep our publications freely accessible we levy an Open Access Publishing Fee for manuscripts, which helps us cover the costs of editorial work and the production of books. Read more
\n\nDigital Archiving Policy
\n\nIntechOpen is committed to ensuring the long-term preservation and the availability of all scholarly research we publish. We employ a variety of means to enable us to deliver on our commitments to the scientific community. Apart from preservation by the Croatian National Library (for publications prior to April 18, 2018) and the British Library (for publications after April 18, 2018), our entire catalogue is preserved in the CLOCKSS archive.
\n\nOpen Science is transparent and accessible knowledge that is shared and developed through collaborative networks.
\n\nOpen Science is about increased rigour, accountability, and reproducibility for research. It is based on the principles of inclusion, fairness, equity, and sharing, and ultimately seeks to change the way research is done, who is involved and how it is valued. It aims to make research more open to participation, review/refutation, improvement and (re)use for the world to benefit.
\n\nOpen Science refers to doing traditional science with more transparency involved at various stages, for example by openly sharing code and data. It implies a growing set of practices - within different disciplines - aiming at:
\n\nWe aim at improving the quality and availability of scholarly communication by promoting and practicing:
\n\n\n'}]},successStories:{items:[]},authorsAndEditors:{filterParams:{sort:"-totalCites"},profiles:[{id:"352625",title:"Dr.",name:"Nanjappa",middleName:null,surname:"Ashwath",slug:"nanjappa-ashwath",fullName:"Nanjappa Ashwath",position:null,profilePictureURL:"https://s3.us-east-1.amazonaws.com/intech-files/0033Y00003633Y6QAI/Profile_Picture_1616134000897",biography:"Associate Professor Nanjappa Ashwath is a plant scientist researching on mine site rehabilitation and native species over the last 30 years. His speciality is in finding the right plant species to a degraded site to ensure that the established species will survive and provide long term ecosystem services. He has researched on restoring uranium mines, coal mines, metalliferous mines, mangrove habitats, roadside verges and railway embankments. He teaches into Australian Botany and Landscape Ecology & Management. Assoc Prof Ashwath supervises post graduate students on a range of topics, including phytoremediation, phytocapping and mine site restoration. His contribution to research at CQU has won him the Vice Chancellor’s Award for research. He has authored/co-authored over 200 publications and serves in the editorial committees of ~10 journals.",institutionString:null,institution:{name:"Central Queensland University",country:{name:"Australia"}}},{id:"131328",title:"Prof.",name:"Abdennasser",middleName:null,surname:"Chebira",slug:"abdennasser-chebira",fullName:"Abdennasser Chebira",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/131328/images/system/131328.jpg",biography:"Dr. Abdennasser Chebira received his Ph.D. degree in Electrical Engineering and Computer Sciences from PARIS XI University, Orsay, France, in 1994. Since September 1994 he works as Professor Assistant at Sénart Institute of Technology of PARIS XII – Val de Marne University. He is a staff researcher at Images, Signal and Intelligent Systems Laboratory (LISSI / EA 3956) of this University. His current research works concern selforganizing neural network based multi-modeling, hybrid neural based information processing systems; Neural based data fusion and complexity estimation.",institutionString:null,institution:null},{id:"262400",title:"Dr.",name:"Thiago Lopes",middleName:null,surname:"Rocha",slug:"thiago-lopes-rocha",fullName:"Thiago Lopes Rocha",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Universidade Federal de Goiás",country:{name:"Brazil"}}},{id:"327936",title:"Dr.",name:"Mohamed",middleName:null,surname:"Anli",slug:"mohamed-anli",fullName:"Mohamed Anli",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"512",title:"Dr.",name:"Dayang",middleName:null,surname:"Jawawi",slug:"dayang-jawawi",fullName:"Dayang Jawawi",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"University of Technology Malaysia",country:{name:"Malaysia"}}},{id:"197120",title:"Mr.",name:"Habib Ur",middleName:null,surname:"Rehman",slug:"habib-ur-rehman",fullName:"Habib Ur Rehman",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"University of Agriculture Faisalabad",country:{name:"Pakistan"}}},{id:"328192",title:"Dr.",name:"Sameer",middleName:null,surname:"Kumar",slug:"sameer-kumar",fullName:"Sameer Kumar",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Central University of Kerala",country:{name:"India"}}},{id:"1024",title:"Dr.",name:"Keinosuke",middleName:null,surname:"Matsumoto",slug:"keinosuke-matsumoto",fullName:"Keinosuke Matsumoto",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Osaka Prefecture University",country:{name:"Japan"}}},{id:"66560",title:"Dr.",name:"Nicole",middleName:null,surname:"Verrills",slug:"nicole-verrills",fullName:"Nicole Verrills",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"University of Newcastle Australia",country:{name:"Australia"}}},{id:"197632",title:"Ph.D.",name:"Karolína",middleName:null,surname:"Barinková",slug:"karolina-barinkova",fullName:"Karolína Barinková",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"University of Pavol Jozef Šafárik",country:{name:"Slovakia"}}},{id:"328704",title:"Dr.",name:"Esther",middleName:null,surname:"Carrillo-Pérez",slug:"esther-carrillo-perez",fullName:"Esther Carrillo-Pérez",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Universidad de Sonora",country:{name:"Mexico"}}},{id:"66816",title:"Dr.",name:"Iwao",middleName:null,surname:"Emura",slug:"iwao-emura",fullName:"Iwao Emura",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Nagaoka Red Cross Hospital",country:{name:"Japan"}}}],filtersByRegion:[{group:"region",caption:"North America",value:1,count:13389},{group:"region",caption:"Middle and South America",value:2,count:11660},{group:"region",caption:"Africa",value:3,count:4168},{group:"region",caption:"Asia",value:4,count:22334},{group:"region",caption:"Australia and Oceania",value:5,count:2019},{group:"region",caption:"Europe",value:6,count:33642}],offset:12,limit:12,total:135275},chapterEmbeded:{data:{}},editorApplication:{success:null,errors:{}},ofsBooks:{filterParams:{hasNoEditors:"1",sort:"-date",topicId:"16"},books:[],filtersByTopic:[{group:"topic",caption:"Agricultural and Biological Sciences",value:5,count:27},{group:"topic",caption:"Biochemistry, Genetics and Molecular Biology",value:6,count:7},{group:"topic",caption:"Business, Management and Economics",value:7,count:4},{group:"topic",caption:"Chemistry",value:8,count:16},{group:"topic",caption:"Computer and Information Science",value:9,count:18},{group:"topic",caption:"Earth and Planetary Sciences",value:10,count:8},{group:"topic",caption:"Engineering",value:11,count:42},{group:"topic",caption:"Environmental Sciences",value:12,count:5},{group:"topic",caption:"Immunology and Microbiology",value:13,count:8},{group:"topic",caption:"Materials Science",value:14,count:17},{group:"topic",caption:"Mathematics",value:15,count:9},{group:"topic",caption:"Medicine",value:16,count:68},{group:"topic",caption:"Nanotechnology and Nanomaterials",value:17,count:3},{group:"topic",caption:"Neuroscience",value:18,count:3},{group:"topic",caption:"Pharmacology, Toxicology and Pharmaceutical Science",value:19,count:7},{group:"topic",caption:"Physics",value:20,count:6},{group:"topic",caption:"Psychology",value:21,count:5},{group:"topic",caption:"Robotics",value:22,count:2},{group:"topic",caption:"Social Sciences",value:23,count:7},{group:"topic",caption:"Veterinary Medicine and Science",value:25,count:2}],offset:0,limit:12,total:null},popularBooks:{featuredBooks:[{type:"book",id:"7827",title:"Interpersonal Relationships",subtitle:null,isOpenForSubmission:!1,hash:"ebf41f4d17c75010eb3294cc8cac3d47",slug:"interpersonal-relationships",bookSignature:"Martha Peaslee Levine",coverURL:"https://cdn.intechopen.com/books/images_new/7827.jpg",editors:[{id:"186919",title:"Dr.",name:"Martha",middleName:null,surname:"Peaslee Levine",slug:"martha-peaslee-levine",fullName:"Martha Peaslee Levine"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10808",title:"Current Concepts in Dental Implantology",subtitle:"From Science to Clinical Research",isOpenForSubmission:!1,hash:"4af8830e463f89c57515c2da2b9777b0",slug:"current-concepts-in-dental-implantology-from-science-to-clinical-research",bookSignature:"Dragana Gabrić and Marko Vuletić",coverURL:"https://cdn.intechopen.com/books/images_new/10808.jpg",editors:[{id:"26946",title:"Prof.",name:"Dragana",middleName:null,surname:"Gabrić",slug:"dragana-gabric",fullName:"Dragana Gabrić"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10796",title:"Extracellular Vesicles",subtitle:"Role in Diseases, Pathogenesis and Therapy",isOpenForSubmission:!1,hash:"eb5407fcf93baff7bca3fae5640153a2",slug:"extracellular-vesicles-role-in-diseases-pathogenesis-and-therapy",bookSignature:"Manash K. Paul",coverURL:"https://cdn.intechopen.com/books/images_new/10796.jpg",editors:[{id:"319365",title:"Assistant Prof.",name:"Manash K.",middleName:null,surname:"Paul",slug:"manash-k.-paul",fullName:"Manash K. Paul"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10908",title:"Advances in Decision Making",subtitle:null,isOpenForSubmission:!1,hash:"126486f7f91e18e2e3539a32c38be7b1",slug:"advances-in-decision-making",bookSignature:"Fausto Pedro García Márquez",coverURL:"https://cdn.intechopen.com/books/images_new/10908.jpg",editors:[{id:"22844",title:"Prof.",name:"Fausto Pedro",middleName:null,surname:"García Márquez",slug:"fausto-pedro-garcia-marquez",fullName:"Fausto Pedro García Márquez"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"95",title:"Applications and Experiences of Quality Control",subtitle:null,isOpenForSubmission:!1,hash:"4bcb22b1eee68210a977a97d5a0f363a",slug:"applications-and-experiences-of-quality-control",bookSignature:"Ognyan Ivanov",coverURL:"https://cdn.intechopen.com/books/images_new/95.jpg",editors:[{id:"22230",title:"Prof.",name:"Ognyan",middleName:null,surname:"Ivanov",slug:"ognyan-ivanov",fullName:"Ognyan Ivanov"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"2160",title:"MATLAB",subtitle:"A Fundamental Tool for Scientific Computing and Engineering Applications - Volume 1",isOpenForSubmission:!1,hash:"dd9c658341fbd264ed4f8d9e6aa8ca29",slug:"matlab-a-fundamental-tool-for-scientific-computing-and-engineering-applications-volume-1",bookSignature:"Vasilios N. Katsikis",coverURL:"https://cdn.intechopen.com/books/images_new/2160.jpg",editors:[{id:"12289",title:"Prof.",name:"Vasilios",middleName:"N.",surname:"Katsikis",slug:"vasilios-katsikis",fullName:"Vasilios Katsikis"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"3560",title:"Advances in Landscape Architecture",subtitle:null,isOpenForSubmission:!1,hash:"a20614517ec5f7e91188fe8e42832138",slug:"advances-in-landscape-architecture",bookSignature:"Murat Özyavuz",coverURL:"https://cdn.intechopen.com/books/images_new/3560.jpg",editors:[{id:"93073",title:"Dr.",name:"Murat",middleName:null,surname:"Ozyavuz",slug:"murat-ozyavuz",fullName:"Murat Ozyavuz"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10739",title:"Global Decline of Insects",subtitle:null,isOpenForSubmission:!1,hash:"543783652b9092962a8fa4bed38eeb17",slug:"global-decline-of-insects",bookSignature:"Hamadttu Abdel Farag El-Shafie",coverURL:"https://cdn.intechopen.com/books/images_new/10739.jpg",editors:[{id:"192142",title:"Dr.",name:"Hamadttu",middleName:null,surname:"Abdel Farag El-Shafie",slug:"hamadttu-abdel-farag-el-shafie",fullName:"Hamadttu Abdel Farag El-Shafie"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10911",title:"Higher Education",subtitle:"New Approaches to Accreditation, Digitalization, and Globalization in the Age of Covid",isOpenForSubmission:!1,hash:"223a02337498e535e967174c1f648fbc",slug:"higher-education-new-approaches-to-accreditation-digitalization-and-globalization-in-the-age-of-covid",bookSignature:"Lee Waller and Sharon Waller",coverURL:"https://cdn.intechopen.com/books/images_new/10911.jpg",editors:[{id:"263301",title:"Dr.",name:"Lee",middleName:null,surname:"Waller",slug:"lee-waller",fullName:"Lee Waller"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"3568",title:"Recent Advances in Plant in vitro Culture",subtitle:null,isOpenForSubmission:!1,hash:"830bbb601742c85a3fb0eeafe1454c43",slug:"recent-advances-in-plant-in-vitro-culture",bookSignature:"Annarita Leva and Laura M. R. Rinaldi",coverURL:"https://cdn.intechopen.com/books/images_new/3568.jpg",editors:[{id:"142145",title:"Dr.",name:"Annarita",middleName:null,surname:"Leva",slug:"annarita-leva",fullName:"Annarita Leva"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"3737",title:"MATLAB",subtitle:"Modelling, Programming and Simulations",isOpenForSubmission:!1,hash:null,slug:"matlab-modelling-programming-and-simulations",bookSignature:"Emilson Pereira Leite",coverURL:"https://cdn.intechopen.com/books/images_new/3737.jpg",editors:[{id:"12051",title:"Prof.",name:"Emilson",middleName:null,surname:"Pereira Leite",slug:"emilson-pereira-leite",fullName:"Emilson Pereira Leite"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"1770",title:"Gel Electrophoresis",subtitle:"Principles and Basics",isOpenForSubmission:!1,hash:"279701f6c802cf02deef45103e0611ff",slug:"gel-electrophoresis-principles-and-basics",bookSignature:"Sameh Magdeldin",coverURL:"https://cdn.intechopen.com/books/images_new/1770.jpg",editors:[{id:"123648",title:"Dr.",name:"Sameh",middleName:null,surname:"Magdeldin",slug:"sameh-magdeldin",fullName:"Sameh Magdeldin"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],offset:12,limit:12,total:4798},hotBookTopics:{hotBooks:[],offset:0,limit:12,total:null},publish:{},publishingProposal:{success:null,errors:{}},books:{featuredBooks:[{type:"book",id:"7827",title:"Interpersonal Relationships",subtitle:null,isOpenForSubmission:!1,hash:"ebf41f4d17c75010eb3294cc8cac3d47",slug:"interpersonal-relationships",bookSignature:"Martha Peaslee Levine",coverURL:"https://cdn.intechopen.com/books/images_new/7827.jpg",publishedDate:"July 27th 2022",numberOfDownloads:7175,editors:[{id:"186919",title:"Dr.",name:"Martha",middleName:null,surname:"Peaslee Levine",slug:"martha-peaslee-levine",fullName:"Martha Peaslee Levine"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10808",title:"Current Concepts in Dental Implantology",subtitle:"From Science to Clinical Research",isOpenForSubmission:!1,hash:"4af8830e463f89c57515c2da2b9777b0",slug:"current-concepts-in-dental-implantology-from-science-to-clinical-research",bookSignature:"Dragana Gabrić and Marko Vuletić",coverURL:"https://cdn.intechopen.com/books/images_new/10808.jpg",publishedDate:"July 27th 2022",numberOfDownloads:1981,editors:[{id:"26946",title:"Prof.",name:"Dragana",middleName:null,surname:"Gabrić",slug:"dragana-gabric",fullName:"Dragana Gabrić"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10796",title:"Extracellular Vesicles",subtitle:"Role in Diseases, Pathogenesis and Therapy",isOpenForSubmission:!1,hash:"eb5407fcf93baff7bca3fae5640153a2",slug:"extracellular-vesicles-role-in-diseases-pathogenesis-and-therapy",bookSignature:"Manash K. Paul",coverURL:"https://cdn.intechopen.com/books/images_new/10796.jpg",publishedDate:"July 20th 2022",numberOfDownloads:2308,editors:[{id:"319365",title:"Assistant Prof.",name:"Manash K.",middleName:null,surname:"Paul",slug:"manash-k.-paul",fullName:"Manash K. Paul"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10908",title:"Advances in Decision Making",subtitle:null,isOpenForSubmission:!1,hash:"126486f7f91e18e2e3539a32c38be7b1",slug:"advances-in-decision-making",bookSignature:"Fausto Pedro García Márquez",coverURL:"https://cdn.intechopen.com/books/images_new/10908.jpg",publishedDate:"July 27th 2022",numberOfDownloads:1473,editors:[{id:"22844",title:"Prof.",name:"Fausto Pedro",middleName:null,surname:"García Márquez",slug:"fausto-pedro-garcia-marquez",fullName:"Fausto Pedro García Márquez"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"95",title:"Applications and Experiences of Quality Control",subtitle:null,isOpenForSubmission:!1,hash:"4bcb22b1eee68210a977a97d5a0f363a",slug:"applications-and-experiences-of-quality-control",bookSignature:"Ognyan Ivanov",coverURL:"https://cdn.intechopen.com/books/images_new/95.jpg",publishedDate:"April 26th 2011",numberOfDownloads:318571,editors:[{id:"22230",title:"Prof.",name:"Ognyan",middleName:null,surname:"Ivanov",slug:"ognyan-ivanov",fullName:"Ognyan Ivanov"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"2160",title:"MATLAB",subtitle:"A Fundamental Tool for Scientific Computing and Engineering Applications - Volume 1",isOpenForSubmission:!1,hash:"dd9c658341fbd264ed4f8d9e6aa8ca29",slug:"matlab-a-fundamental-tool-for-scientific-computing-and-engineering-applications-volume-1",bookSignature:"Vasilios N. Katsikis",coverURL:"https://cdn.intechopen.com/books/images_new/2160.jpg",publishedDate:"September 26th 2012",numberOfDownloads:271836,editors:[{id:"12289",title:"Prof.",name:"Vasilios",middleName:"N.",surname:"Katsikis",slug:"vasilios-katsikis",fullName:"Vasilios Katsikis"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"3560",title:"Advances in Landscape Architecture",subtitle:null,isOpenForSubmission:!1,hash:"a20614517ec5f7e91188fe8e42832138",slug:"advances-in-landscape-architecture",bookSignature:"Murat Özyavuz",coverURL:"https://cdn.intechopen.com/books/images_new/3560.jpg",publishedDate:"July 1st 2013",numberOfDownloads:243450,editors:[{id:"93073",title:"Dr.",name:"Murat",middleName:null,surname:"Ozyavuz",slug:"murat-ozyavuz",fullName:"Murat Ozyavuz"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10739",title:"Global Decline of Insects",subtitle:null,isOpenForSubmission:!1,hash:"543783652b9092962a8fa4bed38eeb17",slug:"global-decline-of-insects",bookSignature:"Hamadttu Abdel Farag El-Shafie",coverURL:"https://cdn.intechopen.com/books/images_new/10739.jpg",publishedDate:"July 20th 2022",numberOfDownloads:1582,editors:[{id:"192142",title:"Dr.",name:"Hamadttu",middleName:null,surname:"Abdel Farag El-Shafie",slug:"hamadttu-abdel-farag-el-shafie",fullName:"Hamadttu Abdel Farag El-Shafie"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10911",title:"Higher Education",subtitle:"New Approaches to Accreditation, Digitalization, and Globalization in the Age of Covid",isOpenForSubmission:!1,hash:"223a02337498e535e967174c1f648fbc",slug:"higher-education-new-approaches-to-accreditation-digitalization-and-globalization-in-the-age-of-covid",bookSignature:"Lee Waller and Sharon Waller",coverURL:"https://cdn.intechopen.com/books/images_new/10911.jpg",publishedDate:"July 13th 2022",numberOfDownloads:2082,editors:[{id:"263301",title:"Dr.",name:"Lee",middleName:null,surname:"Waller",slug:"lee-waller",fullName:"Lee Waller"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"3568",title:"Recent Advances in Plant in vitro Culture",subtitle:null,isOpenForSubmission:!1,hash:"830bbb601742c85a3fb0eeafe1454c43",slug:"recent-advances-in-plant-in-vitro-culture",bookSignature:"Annarita Leva and Laura M. R. Rinaldi",coverURL:"https://cdn.intechopen.com/books/images_new/3568.jpg",publishedDate:"October 17th 2012",numberOfDownloads:256294,editors:[{id:"142145",title:"Dr.",name:"Annarita",middleName:null,surname:"Leva",slug:"annarita-leva",fullName:"Annarita Leva"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],latestBooks:[{type:"book",id:"10808",title:"Current Concepts in Dental Implantology",subtitle:"From Science to Clinical Research",isOpenForSubmission:!1,hash:"4af8830e463f89c57515c2da2b9777b0",slug:"current-concepts-in-dental-implantology-from-science-to-clinical-research",bookSignature:"Dragana Gabrić and Marko Vuletić",coverURL:"https://cdn.intechopen.com/books/images_new/10808.jpg",editedByType:"Edited by",publishedDate:"July 27th 2022",editors:[{id:"26946",title:"Prof.",name:"Dragana",middleName:null,surname:"Gabrić",slug:"dragana-gabric",fullName:"Dragana Gabrić"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"11328",title:"Botulinum Toxin",subtitle:"Recent Topics and Applications",isOpenForSubmission:!1,hash:"7dd05a316001cef143e209eda51387a7",slug:"botulinum-toxin-recent-topics-and-applications",bookSignature:"Suna Sabuncuoglu",coverURL:"https://cdn.intechopen.com/books/images_new/11328.jpg",editedByType:"Edited by",publishedDate:"July 27th 2022",editors:[{id:"270856",title:"Associate Prof.",name:"Suna",middleName:null,surname:"Sabuncuoglu",slug:"suna-sabuncuoglu",fullName:"Suna Sabuncuoglu"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"11085",title:"Polycystic Ovary Syndrome",subtitle:"Functional Investigation and Clinical Application",isOpenForSubmission:!1,hash:"3066dd3ff29e1fac072fd60b08d4d3e7",slug:"polycystic-ovary-syndrome-functional-investigation-and-clinical-application",bookSignature:"Zhengchao Wang",coverURL:"https://cdn.intechopen.com/books/images_new/11085.jpg",editedByType:"Edited by",publishedDate:"July 27th 2022",editors:[{id:"204883",title:"Dr.",name:"Zhengchao",middleName:null,surname:"Wang",slug:"zhengchao-wang",fullName:"Zhengchao Wang"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10833",title:"Tumor Angiogenesis and Modulators",subtitle:null,isOpenForSubmission:!1,hash:"f29b575c46128b2da061ef7f9bd1070b",slug:"tumor-angiogenesis-and-modulators",bookSignature:"Ke Xu",coverURL:"https://cdn.intechopen.com/books/images_new/10833.jpg",editedByType:"Edited by",publishedDate:"July 27th 2022",editors:[{id:"59529",title:"Dr.",name:"Ke",middleName:null,surname:"Xu",slug:"ke-xu",fullName:"Ke Xu"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"11356",title:"Molecular Cloning",subtitle:null,isOpenForSubmission:!1,hash:"671c629dd86e97f0fb467b9e70e92296",slug:"molecular-cloning",bookSignature:"Sadık Dincer, Hatice Aysun Mercimek Takcı and Melis Sumengen Ozdenef",coverURL:"https://cdn.intechopen.com/books/images_new/11356.jpg",editedByType:"Edited by",publishedDate:"July 27th 2022",editors:[{id:"188141",title:"Prof.",name:"Sadik",middleName:null,surname:"Dincer",slug:"sadik-dincer",fullName:"Sadik Dincer"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7827",title:"Interpersonal Relationships",subtitle:null,isOpenForSubmission:!1,hash:"ebf41f4d17c75010eb3294cc8cac3d47",slug:"interpersonal-relationships",bookSignature:"Martha Peaslee Levine",coverURL:"https://cdn.intechopen.com/books/images_new/7827.jpg",editedByType:"Edited by",publishedDate:"July 27th 2022",editors:[{id:"186919",title:"Dr.",name:"Martha",middleName:null,surname:"Peaslee Levine",slug:"martha-peaslee-levine",fullName:"Martha Peaslee Levine"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10908",title:"Advances in Decision Making",subtitle:null,isOpenForSubmission:!1,hash:"126486f7f91e18e2e3539a32c38be7b1",slug:"advances-in-decision-making",bookSignature:"Fausto Pedro García Márquez",coverURL:"https://cdn.intechopen.com/books/images_new/10908.jpg",editedByType:"Edited by",publishedDate:"July 27th 2022",editors:[{id:"22844",title:"Prof.",name:"Fausto Pedro",middleName:null,surname:"García Márquez",slug:"fausto-pedro-garcia-marquez",fullName:"Fausto Pedro García Márquez"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10669",title:"Corrosion",subtitle:"Fundamentals and Protection Mechanisms",isOpenForSubmission:!1,hash:"4a76d54f8a40fc2e7002a8d13fd617c1",slug:"corrosion-fundamentals-and-protection-mechanisms",bookSignature:"Fahmina Zafar, Anujit Ghosal and Eram Sharmin",coverURL:"https://cdn.intechopen.com/books/images_new/10669.jpg",editedByType:"Edited by",publishedDate:"July 27th 2022",editors:[{id:"89672",title:"Dr.",name:"Fahmina",middleName:null,surname:"Zafar",slug:"fahmina-zafar",fullName:"Fahmina Zafar"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10677",title:"Advanced Topics of Topology",subtitle:null,isOpenForSubmission:!1,hash:"bf964c52f9e653fac20a7fcab58070e5",slug:"advanced-topics-of-topology",bookSignature:"Francisco Bulnes",coverURL:"https://cdn.intechopen.com/books/images_new/10677.jpg",editedByType:"Edited by",publishedDate:"July 27th 2022",editors:[{id:"92918",title:"Dr.",name:"Francisco",middleName:null,surname:"Bulnes",slug:"francisco-bulnes",fullName:"Francisco Bulnes"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"11195",title:"Recent Advances in Biometrics",subtitle:null,isOpenForSubmission:!1,hash:"2d32e33e0f499cb5241734bb75dd2a83",slug:"recent-advances-in-biometrics",bookSignature:"Muhammad Sarfraz",coverURL:"https://cdn.intechopen.com/books/images_new/11195.jpg",editedByType:"Edited by",publishedDate:"July 27th 2022",editors:[{id:"215610",title:"Prof.",name:"Muhammad",middleName:null,surname:"Sarfraz",slug:"muhammad-sarfraz",fullName:"Muhammad Sarfraz"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}]},subject:{topic:{id:"85",title:"Organic Chemistry",slug:"organic-chemistry",parent:{id:"8",title:"Chemistry",slug:"chemistry"},numberOfBooks:64,numberOfSeries:0,numberOfAuthorsAndEditors:1569,numberOfWosCitations:3773,numberOfCrossrefCitations:2188,numberOfDimensionsCitations:5369,videoUrl:null,fallbackUrl:null,description:null},booksByTopicFilter:{topicId:"85",sort:"-publishedDate",limit:12,offset:0},booksByTopicCollection:[{type:"book",id:"10840",title:"Benzimidazole",subtitle:null,isOpenForSubmission:!1,hash:"e28c770013e7a8dd0fc37aea6aa9def8",slug:"benzimidazole",bookSignature:"Pravin Kendrekar and Vinayak Adimule",coverURL:"https://cdn.intechopen.com/books/images_new/10840.jpg",editedByType:"Edited by",editors:[{id:"310674",title:"Dr.",name:"Pravin",middleName:null,surname:"Kendrekar",slug:"pravin-kendrekar",fullName:"Pravin Kendrekar"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"11332",title:"Essential Oils",subtitle:"Advances in Extractions and Biological Applications",isOpenForSubmission:!1,hash:"742e6cae3a35686f975edc8d7f9afa94",slug:"essential-oils-advances-in-extractions-and-biological-applications",bookSignature:"Mozaniel Santana de Oliveira and Eloisa Helena de Aguiar Andrade",coverURL:"https://cdn.intechopen.com/books/images_new/11332.jpg",editedByType:"Edited by",editors:[{id:"195290",title:"Ph.D.",name:"Mozaniel",middleName:null,surname:"Santana De Oliveira",slug:"mozaniel-santana-de-oliveira",fullName:"Mozaniel Santana De Oliveira"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10861",title:"Furan Derivatives",subtitle:"Recent Advances and Applications",isOpenForSubmission:!1,hash:"fdfc39cecd82f91b0effac994f75c877",slug:"furan-derivatives-recent-advances-and-applications",bookSignature:"Anish Khan, Mohammed Muzibur Rahman, M. Ramesh, Salman Ahmad Khan and Abdullah Mohammed Ahmed Asiri",coverURL:"https://cdn.intechopen.com/books/images_new/10861.jpg",editedByType:"Edited by",editors:[{id:"293058",title:"Dr.",name:"Anish",middleName:null,surname:"Khan",slug:"anish-khan",fullName:"Anish Khan"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10999",title:"Carbene",subtitle:null,isOpenForSubmission:!1,hash:"605a68d742896b92a81b245cdacc150a",slug:"carbene",bookSignature:"Satyen Saha and Arunava Manna",coverURL:"https://cdn.intechopen.com/books/images_new/10999.jpg",editedByType:"Edited by",editors:[{id:"226917",title:"Dr.",name:"Satyen",middleName:null,surname:"Saha",slug:"satyen-saha",fullName:"Satyen Saha"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10884",title:"Bisphenols",subtitle:null,isOpenForSubmission:!1,hash:"d73ec720cb7577731662ac9d02879729",slug:"bisphenols",bookSignature:"Pınar Erkekoğlu",coverURL:"https://cdn.intechopen.com/books/images_new/10884.jpg",editedByType:"Edited by",editors:[{id:"109978",title:"Prof.",name:"Pınar",middleName:null,surname:"Erkekoglu",slug:"pinar-erkekoglu",fullName:"Pınar Erkekoglu"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10799",title:"Phenolic Compounds",subtitle:"Chemistry, Synthesis, Diversity, Non-Conventional Industrial, Pharmaceutical and Therapeutic Applications",isOpenForSubmission:!1,hash:"339199f254d2987ef3167eef74fb8a38",slug:"phenolic-compounds-chemistry-synthesis-diversity-non-conventional-industrial-pharmaceutical-and-therapeutic-applications",bookSignature:"Farid A. Badria",coverURL:"https://cdn.intechopen.com/books/images_new/10799.jpg",editedByType:"Edited by",editors:[{id:"41865",title:"Prof.",name:"Farid A.",middleName:null,surname:"Badria",slug:"farid-a.-badria",fullName:"Farid A. Badria"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10443",title:"Accenting Lipid Peroxidation",subtitle:null,isOpenForSubmission:!1,hash:"783b476008fbd1917ab059fb9f07b93c",slug:"accenting-lipid-peroxidation",bookSignature:"Pınar Atukeren",coverURL:"https://cdn.intechopen.com/books/images_new/10443.jpg",editedByType:"Edited by",editors:[{id:"54960",title:"Dr.",name:"Pınar",middleName:null,surname:"Atukeren",slug:"pinar-atukeren",fullName:"Pınar Atukeren"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10776",title:"Cellulose Science and Derivatives",subtitle:null,isOpenForSubmission:!1,hash:"947660259ce1915c3cac58bf7d990424",slug:"cellulose-science-and-derivatives",bookSignature:"Arpit Sand and Sangita Banga",coverURL:"https://cdn.intechopen.com/books/images_new/10776.jpg",editedByType:"Edited by",editors:[{id:"287032",title:"Associate Prof.",name:"Arpit",middleName:null,surname:"Sand",slug:"arpit-sand",fullName:"Arpit Sand"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10701",title:"Alkenes",subtitle:"Recent Advances, New Perspectives and Applications",isOpenForSubmission:!1,hash:"f6dd394ef1ca2d6472220de6a79a0d9a",slug:"alkenes-recent-advances-new-perspectives-and-applications",bookSignature:"Reza Davarnejad",coverURL:"https://cdn.intechopen.com/books/images_new/10701.jpg",editedByType:"Edited by",editors:[{id:"88069",title:"Associate Prof.",name:"Reza",middleName:null,surname:"Davarnejad",slug:"reza-davarnejad",fullName:"Reza Davarnejad"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10507",title:"Current Topics in Chirality",subtitle:"From Chemistry to Biology",isOpenForSubmission:!1,hash:"692993cd6e2996714124df690df7c2e9",slug:"current-topics-in-chirality-from-chemistry-to-biology",bookSignature:"Takashiro Akitsu",coverURL:"https://cdn.intechopen.com/books/images_new/10507.jpg",editedByType:"Edited by",editors:[{id:"147861",title:"Dr.",name:"Takashiro",middleName:null,surname:"Akitsu",slug:"takashiro-akitsu",fullName:"Takashiro Akitsu"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9753",title:"Terpenes and Terpenoids",subtitle:"Recent Advances",isOpenForSubmission:!1,hash:"575689df13c78bf0e6c1be40804cd010",slug:"terpenes-and-terpenoids-recent-advances",bookSignature:"Shagufta Perveen and Areej Mohammad Al-Taweel",coverURL:"https://cdn.intechopen.com/books/images_new/9753.jpg",editedByType:"Edited by",editors:[{id:"192992",title:"Prof.",name:"Shagufta",middleName:null,surname:"Perveen",slug:"shagufta-perveen",fullName:"Shagufta Perveen"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9953",title:"Azoles",subtitle:"Synthesis, Properties, Applications and Perspectives",isOpenForSubmission:!1,hash:"87a84470866a4c146b5c9c8e46185779",slug:"azoles-synthesis-properties-applications-and-perspectives",bookSignature:"Aleksey Kuznetsov",coverURL:"https://cdn.intechopen.com/books/images_new/9953.jpg",editedByType:"Edited by",editors:[{id:"201033",title:"Prof.",name:"Aleksey",middleName:null,surname:"Kuznetsov",slug:"aleksey-kuznetsov",fullName:"Aleksey Kuznetsov"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}],booksByTopicTotal:64,seriesByTopicCollection:[],seriesByTopicTotal:0,mostCitedChapters:[{id:"36171",doi:"10.5772/36942",title:"Research of Calcium Phosphates Using Fourier Transform Infrared Spectroscopy",slug:"research-of-calcium-phosphates-using-fourier-transformation-infrared-spectroscopy",totalDownloads:9277,totalCrossrefCites:132,totalDimensionsCites:381,abstract:null,book:{id:"1591",slug:"infrared-spectroscopy-materials-science-engineering-and-technology",title:"Infrared Spectroscopy",fullTitle:"Infrared Spectroscopy - Materials Science, Engineering and Technology"},signatures:"Liga Berzina-Cimdina and Natalija Borodajenko",authors:[{id:"110522",title:"Prof.",name:"Liga",middleName:null,surname:"Berzina-Cimdina",slug:"liga-berzina-cimdina",fullName:"Liga Berzina-Cimdina"},{id:"112181",title:"MSc.",name:"Natalija",middleName:null,surname:"Borodajenko",slug:"natalija-borodajenko",fullName:"Natalija Borodajenko"}]},{id:"36178",doi:"10.5772/36323",title:"Applications of FTIR on Epoxy Resins - Identification, Monitoring the Curing Process, Phase Separation and Water Uptake",slug:"applications-of-ftir-on-epoxy-resins-identification-monitoring-the-curing-process-phase-separatio",totalDownloads:20869,totalCrossrefCites:84,totalDimensionsCites:260,abstract:null,book:{id:"1591",slug:"infrared-spectroscopy-materials-science-engineering-and-technology",title:"Infrared Spectroscopy",fullTitle:"Infrared Spectroscopy - Materials Science, Engineering and Technology"},signatures:"María González González, Juan Carlos Cabanelas and Juan Baselga",authors:[{id:"107857",title:"Prof.",name:"Juan",middleName:null,surname:"Baselga",slug:"juan-baselga",fullName:"Juan Baselga"},{id:"138113",title:"Dr.",name:"María",middleName:null,surname:"González",slug:"maria-gonzalez",fullName:"María González"},{id:"138114",title:"Dr.",name:"Juan C.",middleName:null,surname:"Cabanelas",slug:"juan-c.-cabanelas",fullName:"Juan C. Cabanelas"}]},{id:"53973",doi:"10.5772/66927",title:"Phenolic Compounds in Water: Sources, Reactivity, Toxicity and Treatment Methods",slug:"phenolic-compounds-in-water-sources-reactivity-toxicity-and-treatment-methods",totalDownloads:7324,totalCrossrefCites:77,totalDimensionsCites:170,abstract:"Phenolic compounds exist in water bodies due to the discharge of polluted wastewater from industrial, agricultural and domestic activities into water bodies. They also occur as a result of natural phenomena. These compounds are known to be toxic and inflict both severe and long‐lasting effects on both humans and animals. They act as carcinogens and cause damage to the red blood cells and the liver, even at low concentrations. Interaction of these compounds with microorganisms, inorganic and other organic compounds in water can produce substituted compounds or other moieties, which may be as toxic as the original phenolic compounds. This chapter dwells on the sources and reactivity of phenolic compounds in water, their toxic effects on humans, and methods of their removal from water. Specific emphasis is placed on the techniques of their removal from water with attention on both conventional and advanced methods. Among these methods are ozonation, adsorption, extraction, photocatalytic degradation, biological, electro‐Fenton, adsorption and ion exchange and membrane‐based separation.",book:{id:"6029",slug:"phenolic-compounds-natural-sources-importance-and-applications",title:"Phenolic Compounds",fullTitle:"Phenolic Compounds - Natural Sources, Importance and Applications"},signatures:"William W. Anku, Messai A. Mamo and Penny P. Govender",authors:[{id:"195237",title:"Dr.",name:"Messai",middleName:"A.",surname:"Mamo",slug:"messai-mamo",fullName:"Messai Mamo"},{id:"196465",title:"Dr.",name:"William Wilson",middleName:null,surname:"Anku",slug:"william-wilson-anku",fullName:"William Wilson Anku"},{id:"196466",title:"Dr.",name:"Penny",middleName:null,surname:"Govender",slug:"penny-govender",fullName:"Penny Govender"}]},{id:"36184",doi:"10.5772/36186",title:"Infrared Spectroscopy in the Analysis of Building and Construction Materials",slug:"infrared-spectroscopy-of-cementitious-materials",totalDownloads:7817,totalCrossrefCites:77,totalDimensionsCites:157,abstract:null,book:{id:"1591",slug:"infrared-spectroscopy-materials-science-engineering-and-technology",title:"Infrared Spectroscopy",fullTitle:"Infrared Spectroscopy - Materials Science, Engineering and Technology"},signatures:"Lucia Fernández-Carrasco, D. Torrens-Martín, L.M. Morales and Sagrario Martínez-Ramírez",authors:[{id:"107401",title:"Dr.",name:"Lucia J",middleName:null,surname:"Fernández",slug:"lucia-j-fernandez",fullName:"Lucia J Fernández"}]},{id:"53128",doi:"10.5772/66368",title:"Phenolic Compounds: Functional Properties, Impact of Processing and Bioavailability",slug:"phenolic-compounds-functional-properties-impact-of-processing-and-bioavailability",totalDownloads:9393,totalCrossrefCites:78,totalDimensionsCites:149,abstract:"In this chapter, we discuss the influence of the processing methods on the content of phenolic compounds in fruits and vegetables. The intake of fruits and vegetables based‐foods are associated with delayed aging and a decreased risk of chronic disease development. Fruits and vegetables can be consumed in natura, but the highest amounts are ingested after some processing methods, such as cooking procedures or sanitizing methods. These methods are directly methods are directly related to alteration on the phenolic content. In addition, the postharvest conditions may modify several phytochemical substances. Phenolic compounds are referred to as phytochemicals found in a large number of foods and beverages. The relative high diversity of these molecules produced by plants must be taken into account when methods of preparation are employed to obtain industrial or homemade products. Phenolic compounds comprise one (phenolic acids) or more (polyphenols) aromatic rings with attached hydroxyl groups in their structures. Their antioxidant capacities are related to these hydroxyl groups and phenolic rings. Despite the antioxidant activity, they have many other beneficial effects on human health. However, before attributing health benefits to these compounds, absorption, distribution, and metabolism of each phenolic compound in the body are important points that should be considered.",book:{id:"5609",slug:"phenolic-compounds-biological-activity",title:"Phenolic Compounds",fullTitle:"Phenolic Compounds - Biological Activity"},signatures:"Igor Otavio Minatel, Cristine Vanz Borges, Maria Izabela Ferreira,\nHector Alonzo Gomez Gomez, Chung-Yen Oliver Chen and\nGiuseppina Pace Pereira Lima",authors:[{id:"146379",title:"Dr.",name:"Giuseppina",middleName:null,surname:"Lima",slug:"giuseppina-lima",fullName:"Giuseppina Lima"},{id:"194002",title:"MSc.",name:"Cristine",middleName:null,surname:"Vanz Borges",slug:"cristine-vanz-borges",fullName:"Cristine Vanz Borges"},{id:"194003",title:"Prof.",name:"Igor Otavio",middleName:null,surname:"Minatel",slug:"igor-otavio-minatel",fullName:"Igor Otavio Minatel"},{id:"194004",title:"Dr.",name:"Maria Izabela",middleName:null,surname:"Ferreira",slug:"maria-izabela-ferreira",fullName:"Maria Izabela Ferreira"},{id:"194005",title:"Prof.",name:"Hector",middleName:null,surname:"Gomez-Gomez",slug:"hector-gomez-gomez",fullName:"Hector Gomez-Gomez"},{id:"194006",title:"Prof.",name:"Chung-Yen Oliver",middleName:null,surname:"Chen",slug:"chung-yen-oliver-chen",fullName:"Chung-Yen Oliver Chen"}]}],mostDownloadedChaptersLast30Days:[{id:"53973",title:"Phenolic Compounds in Water: Sources, Reactivity, Toxicity and Treatment Methods",slug:"phenolic-compounds-in-water-sources-reactivity-toxicity-and-treatment-methods",totalDownloads:7324,totalCrossrefCites:77,totalDimensionsCites:170,abstract:"Phenolic compounds exist in water bodies due to the discharge of polluted wastewater from industrial, agricultural and domestic activities into water bodies. They also occur as a result of natural phenomena. These compounds are known to be toxic and inflict both severe and long‐lasting effects on both humans and animals. They act as carcinogens and cause damage to the red blood cells and the liver, even at low concentrations. Interaction of these compounds with microorganisms, inorganic and other organic compounds in water can produce substituted compounds or other moieties, which may be as toxic as the original phenolic compounds. This chapter dwells on the sources and reactivity of phenolic compounds in water, their toxic effects on humans, and methods of their removal from water. Specific emphasis is placed on the techniques of their removal from water with attention on both conventional and advanced methods. Among these methods are ozonation, adsorption, extraction, photocatalytic degradation, biological, electro‐Fenton, adsorption and ion exchange and membrane‐based separation.",book:{id:"6029",slug:"phenolic-compounds-natural-sources-importance-and-applications",title:"Phenolic Compounds",fullTitle:"Phenolic Compounds - Natural Sources, Importance and Applications"},signatures:"William W. Anku, Messai A. Mamo and Penny P. Govender",authors:[{id:"195237",title:"Dr.",name:"Messai",middleName:"A.",surname:"Mamo",slug:"messai-mamo",fullName:"Messai Mamo"},{id:"196465",title:"Dr.",name:"William Wilson",middleName:null,surname:"Anku",slug:"william-wilson-anku",fullName:"William Wilson Anku"},{id:"196466",title:"Dr.",name:"Penny",middleName:null,surname:"Govender",slug:"penny-govender",fullName:"Penny Govender"}]},{id:"53128",title:"Phenolic Compounds: Functional Properties, Impact of Processing and Bioavailability",slug:"phenolic-compounds-functional-properties-impact-of-processing-and-bioavailability",totalDownloads:9392,totalCrossrefCites:78,totalDimensionsCites:149,abstract:"In this chapter, we discuss the influence of the processing methods on the content of phenolic compounds in fruits and vegetables. The intake of fruits and vegetables based‐foods are associated with delayed aging and a decreased risk of chronic disease development. Fruits and vegetables can be consumed in natura, but the highest amounts are ingested after some processing methods, such as cooking procedures or sanitizing methods. These methods are directly methods are directly related to alteration on the phenolic content. In addition, the postharvest conditions may modify several phytochemical substances. Phenolic compounds are referred to as phytochemicals found in a large number of foods and beverages. The relative high diversity of these molecules produced by plants must be taken into account when methods of preparation are employed to obtain industrial or homemade products. Phenolic compounds comprise one (phenolic acids) or more (polyphenols) aromatic rings with attached hydroxyl groups in their structures. Their antioxidant capacities are related to these hydroxyl groups and phenolic rings. Despite the antioxidant activity, they have many other beneficial effects on human health. However, before attributing health benefits to these compounds, absorption, distribution, and metabolism of each phenolic compound in the body are important points that should be considered.",book:{id:"5609",slug:"phenolic-compounds-biological-activity",title:"Phenolic Compounds",fullTitle:"Phenolic Compounds - Biological Activity"},signatures:"Igor Otavio Minatel, Cristine Vanz Borges, Maria Izabela Ferreira,\nHector Alonzo Gomez Gomez, Chung-Yen Oliver Chen and\nGiuseppina Pace Pereira Lima",authors:[{id:"146379",title:"Dr.",name:"Giuseppina",middleName:null,surname:"Lima",slug:"giuseppina-lima",fullName:"Giuseppina Lima"},{id:"194002",title:"MSc.",name:"Cristine",middleName:null,surname:"Vanz Borges",slug:"cristine-vanz-borges",fullName:"Cristine Vanz Borges"},{id:"194003",title:"Prof.",name:"Igor Otavio",middleName:null,surname:"Minatel",slug:"igor-otavio-minatel",fullName:"Igor Otavio Minatel"},{id:"194004",title:"Dr.",name:"Maria Izabela",middleName:null,surname:"Ferreira",slug:"maria-izabela-ferreira",fullName:"Maria Izabela Ferreira"},{id:"194005",title:"Prof.",name:"Hector",middleName:null,surname:"Gomez-Gomez",slug:"hector-gomez-gomez",fullName:"Hector Gomez-Gomez"},{id:"194006",title:"Prof.",name:"Chung-Yen Oliver",middleName:null,surname:"Chen",slug:"chung-yen-oliver-chen",fullName:"Chung-Yen Oliver Chen"}]},{id:"45635",title:"Application of Cellulose and Cellulose Derivatives in Pharmaceutical Industries",slug:"application-of-cellulose-and-cellulose-derivatives-in-pharmaceutical-industries",totalDownloads:10348,totalCrossrefCites:60,totalDimensionsCites:138,abstract:null,book:{id:"3173",slug:"cellulose-medical-pharmaceutical-and-electronic-applications",title:"Cellulose",fullTitle:"Cellulose - Medical, Pharmaceutical and Electronic Applications"},signatures:"Javad Shokri and Khosro Adibkia",authors:[{id:"140056",title:"Prof.",name:"Javad",middleName:null,surname:"Shokri",slug:"javad-shokri",fullName:"Javad Shokri"}]},{id:"57200",title:"Introductory Chapter: Principles of Green Chemistry",slug:"introductory-chapter-principles-of-green-chemistry",totalDownloads:2816,totalCrossrefCites:2,totalDimensionsCites:7,abstract:null,book:{id:"6067",slug:"green-chemistry",title:"Green Chemistry",fullTitle:"Green Chemistry"},signatures:"Hosam El-Din Mostafa Saleh and M. Koller",authors:[{id:"144691",title:"Prof.",name:"Hosam M.",middleName:null,surname:"Saleh",slug:"hosam-m.-saleh",fullName:"Hosam M. Saleh"},{id:"218817",title:"Dr.",name:"Martin",middleName:null,surname:"Koller",slug:"martin-koller",fullName:"Martin Koller"}]},{id:"66517",title:"Microbial Cellulases: An Overview and Applications",slug:"microbial-cellulases-an-overview-and-applications",totalDownloads:3563,totalCrossrefCites:42,totalDimensionsCites:91,abstract:"Cellulases are a complex group of enzymes which are secreted by a broad range of microorganisms including fungi, bacteria, and actinomycetes. In the natural environment, synergistic interactions among cellulolytic microorganisms play an important role in the hydrolysis of lignocellulosic polymer materials. In fact, it is the combined action of three major enzymes which determines the efficiency of this process. They are exoglucanases, endoglucanases, and β-glucosidase. Microorganisms produce these enzymes in a diverse nature which determines their efficiency in cellulose hydrolysis. During the cellulose degradation reaction, the enzyme targets the β-1,4-linkages in its polymeric structure. This is an essential ecological process as it recycles cellulose in the biosphere. The application of this same scenario for industrial purposes is identified as an emerging area of research. Biofuel production, textile polishing and finishing, paper and pulp industry, and lifestyle agriculture are among the key areas where cellulase enzyme shows a broader potential. The objective of this chapter is to discuss the structure, function, possible applications, as well as novel biotechnological trends of cellulase enzymes. Furthermore, possible low-cost, enzymatic pretreatment methods of lignocellulosic material in order to use it as an efficient raw material for biofuel production will be discussed.",book:{id:"7363",slug:"cellulose",title:"Cellulose",fullTitle:"Cellulose"},signatures:"Sandhya Jayasekara and Renuka Ratnayake",authors:null}],onlineFirstChaptersFilter:{topicId:"85",limit:6,offset:0},onlineFirstChaptersCollection:[{id:"65119",title:"Introductory Chapter: Polyaniline - From Synthesis to Practical Applications",slug:"introductory-chapter-polyaniline-from-synthesis-to-practical-applications",totalDownloads:975,totalDimensionsCites:2,doi:"10.5772/intechopen.83397",abstract:null,book:{id:"7503",title:"Polyaniline - From Synthesis to Practical Applications",coverURL:"https://cdn.intechopen.com/books/images_new/7503.jpg"},signatures:"Florin Nastase"}],onlineFirstChaptersTotal:1},preDownload:{success:null,errors:{}},subscriptionForm:{success:null,errors:{}},aboutIntechopen:{},privacyPolicy:{},peerReviewing:{},howOpenAccessPublishingWithIntechopenWorks:{},sponsorshipBooks:{sponsorshipBooks:[],offset:8,limit:8,total:0},allSeries:{pteSeriesList:[{id:"14",title:"Artificial Intelligence",numberOfPublishedBooks:9,numberOfPublishedChapters:90,numberOfOpenTopics:6,numberOfUpcomingTopics:0,issn:"2633-1403",doi:"10.5772/intechopen.79920",isOpenForSubmission:!0},{id:"7",title:"Biomedical Engineering",numberOfPublishedBooks:12,numberOfPublishedChapters:107,numberOfOpenTopics:3,numberOfUpcomingTopics:0,issn:"2631-5343",doi:"10.5772/intechopen.71985",isOpenForSubmission:!0}],lsSeriesList:[{id:"11",title:"Biochemistry",numberOfPublishedBooks:33,numberOfPublishedChapters:330,numberOfOpenTopics:4,numberOfUpcomingTopics:0,issn:"2632-0983",doi:"10.5772/intechopen.72877",isOpenForSubmission:!0},{id:"25",title:"Environmental Sciences",numberOfPublishedBooks:1,numberOfPublishedChapters:19,numberOfOpenTopics:4,numberOfUpcomingTopics:0,issn:"2754-6713",doi:"10.5772/intechopen.100362",isOpenForSubmission:!0},{id:"10",title:"Physiology",numberOfPublishedBooks:14,numberOfPublishedChapters:145,numberOfOpenTopics:4,numberOfUpcomingTopics:0,issn:"2631-8261",doi:"10.5772/intechopen.72796",isOpenForSubmission:!0}],hsSeriesList:[{id:"3",title:"Dentistry",numberOfPublishedBooks:9,numberOfPublishedChapters:139,numberOfOpenTopics:2,numberOfUpcomingTopics:0,issn:"2631-6218",doi:"10.5772/intechopen.71199",isOpenForSubmission:!0},{id:"6",title:"Infectious Diseases",numberOfPublishedBooks:13,numberOfPublishedChapters:122,numberOfOpenTopics:4,numberOfUpcomingTopics:0,issn:"2631-6188",doi:"10.5772/intechopen.71852",isOpenForSubmission:!0},{id:"13",title:"Veterinary Medicine and Science",numberOfPublishedBooks:11,numberOfPublishedChapters:112,numberOfOpenTopics:3,numberOfUpcomingTopics:0,issn:"2632-0517",doi:"10.5772/intechopen.73681",isOpenForSubmission:!0}],sshSeriesList:[{id:"22",title:"Business, Management and Economics",numberOfPublishedBooks:1,numberOfPublishedChapters:21,numberOfOpenTopics:3,numberOfUpcomingTopics:0,issn:"2753-894X",doi:"10.5772/intechopen.100359",isOpenForSubmission:!0},{id:"23",title:"Education and Human Development",numberOfPublishedBooks:0,numberOfPublishedChapters:10,numberOfOpenTopics:1,numberOfUpcomingTopics:1,issn:null,doi:"10.5772/intechopen.100360",isOpenForSubmission:!0},{id:"24",title:"Sustainable Development",numberOfPublishedBooks:1,numberOfPublishedChapters:19,numberOfOpenTopics:5,numberOfUpcomingTopics:0,issn:"2753-6580",doi:"10.5772/intechopen.100361",isOpenForSubmission:!0}],testimonialsList:[{id:"13",text:"The collaboration with and support of the technical staff of IntechOpen is fantastic. The whole process of submitting an article and editing of the submitted article goes extremely smooth and fast, the number of reads and downloads of chapters is high, and the contributions are also frequently cited.",author:{id:"55578",name:"Antonio",surname:"Jurado-Navas",institutionString:null,profilePictureURL:"https://s3.us-east-1.amazonaws.com/intech-files/0030O00002bRisIQAS/Profile_Picture_1626166543950",slug:"antonio-jurado-navas",institution:{id:"720",name:"University of Malaga",country:{id:null,name:"Spain"}}}},{id:"6",text:"It is great to work with the IntechOpen to produce a worthwhile collection of research that also becomes a great educational resource and guide for future research endeavors.",author:{id:"259298",name:"Edward",surname:"Narayan",institutionString:null,profilePictureURL:"https://mts.intechopen.com/storage/users/259298/images/system/259298.jpeg",slug:"edward-narayan",institution:{id:"3",name:"University of Queensland",country:{id:null,name:"Australia"}}}}]},series:{item:{id:"24",title:"Sustainable Development",doi:"10.5772/intechopen.100361",issn:"2753-6580",scope:"