The Evolving Landscape of Colonoscopy: Recent Developments and Complication Management

Abstract

Colorectal cancer is globally recognized as the third most prevalent cancer, highlighting the crucial role of colonoscopy in diagnosis and therapeutic interventions. This medical procedure has demonstrated its effectiveness in preventing colorectal cancer and investigating a wide range of gastrointestinal symptoms. It has long been acknowledged as the gold standard for screening colorectal cancer. The primary objective of this analysis is to outline diverse range of complications associated with preparatory phase of colonoscopy, especially among hospitalized patients, including those with potentially life-threatening conditions. The ultimate aim is to elucidate strategies to prevent complications during the preparatory phase of colonoscopy. The real-time visual feed produced by endoscopic camera allows for the detection of abnormal growth of the colonic wall. This capability facilitates the assessment, biopsy, and removal of mucosal lesions through various biopsy instruments accessible via specialized channels. With its multifaceted utility, colonoscopy has become a frontline approach in making colorectal cancer a preventable and early-detectable disease over the past few decades. Common complications associated with colonoscopy include occurrences like vomiting, nosebleeds, abdominal pain, and acute diarrhoea. This review primarily focuses on developments that have transpired over the past five years, leading to changes in multiple aspects of colonoscopy.

1. Introduction

In today’s contemporary medicine, a colonoscopy is an essential procedure. This approach is essential for saving lives in both immediate and future situations because of its adaptability and usefulness. It is applicable to both cancerous and noncancerous disorders, such as colon impactions, sigmoid volvulus infections, and gastrointestinal hemorrhage. Performing a colonoscopy for screening purposes is crucial in identifying and addressing colorectal cancers in their early stages. This procedure plays a significant role in guiding the course of cancer treatment, assisting in the planning of surgical measures [1]. Recent colonoscopies face a number of difficulties because of the unique characteristics of the colon, including the possibility of a highly repetitive sigmoid colon in certain people. In certain cases, the transverse colon forms an M shape and goes down into the pelvis. The colon’s mostly round shape leads to a semi-circular pattern within the scope after a few twists and further advancement increases the risk of forming a larger loop. At the same time, the tip of the scope does not proceed forward [2].

2. Basics of colonoscopy

The United States performs over 15 million colonoscopies annually, and it is estimated that these procedures lower the overall risk of dying from colorectal cancer by more than 60% [3]. Because of advancements in upper endoscopy, colonoscopy was initially introduced in the 1960s [4]. Colonoscopy is a diagnosis and curative technique used to assess the distal part of the small intestine and the large intestine. The procedure is carried out with the use of a versatile, hand-held tube-like instrument known as a colonoscope. It includes an attached high-definition camera at its tip and auxiliary channels that enable the insertion of tools and liquids to clean the colonoscope lens and the mucosa of the colon [5]. The imagery captured by the camera and displayed on the screen aids in identifying irregularities and excessive growth on the colon wall. Consequently, this technology enables the assessment, sampling, and elimination of mucosal lesions using various biopsy tools accessible through additional channels. To detect and treat colorectal cancer, a colonoscopy is essential. It is a suggested screening method for people with risk factors, such as a family history of cancer or tumors, and is the best way to find cancerous colonies [6]. Progressive advancements in imaging technology, the evolution of guidelines, heightened awareness, and expanded access have collectively contributed to increased utilization and broader utility. In this review, we will explore the various kinds, uses, and potential complications of colonoscopies, along with their management strategies, future advancements, and the scope of their application. The colon and colonoscopy are shown in Figure 1.

Figure 1.

Colon and colonoscopy.

2.1 History and the need for colonoscopy

Colon cancer is more likely to strike an older person. Although it can be identified in younger persons, it is far more frequent after the age of 45 years. The cause of the rising incidence of colon cancer in people aged under 45 years is unknown [7]. A background of adenomatous polyps elevates the likelihood of developing colon cancer, particularly in cases involving large polyps, multiple polyps, or those displaying dysplasia. Following the identification of polyps and the assessment of results, the gastroenterologist will suggest a screening timetable tailored to individual-specific risk factors [8].

2.1.1 Family past with cancer or polyps in the colon

Although the majority of colon cancers occur in individuals without a family history, up to one-third of individuals diagnosed with colon cancer have relatives who have also experienced the disease. Adenomatous polyps, the type of polyps that have the potential to turn cancerous, have been linked to a greater chance of developing colon cancer in family members. The reason for this is not fully apparent. Because of heredity, the environment, or a mix of both, cancer may be passed down in families.

2.1.2 Personal history of inflammatory bowel disease (IBD)

Suffering from IBD such as ulcerative colitis or Crohn’s disease heightens the likelihood of developing colon cancer. It is essential to note that IBD should not be confused with irritable bowel syndrome (IBS), which does not seem to elevate the risk of colon cancer. Individuals with IBD might necessitate earlier initiation of colon cancer screening and more frequent screenings [9].

2.1.3 Signs of colon cancer

Although most early cases of colon cancer are asymptomatic, anybody experiencing symptoms such as bleeding in the feces, bleeding from the rectal area, pain in the stomach, and unexpected weight loss should see a gastroenterologist.

2.2 Types of colonoscopies

There are two kinds of colonoscopies: screening and diagnostic.

2.2.1 Screening colonoscopy

A screening colonoscopy is a proactive examination performed to ensure the colon’s good health. If a person has a first-degree relative with a medical history of colon polyps or cancer, has potential indicators for colorectal cancer, or has had a colon polyp or cancer in the past, they may need a preventative colonoscopy for screening purposes.

2.2.2 Diagnostic colonoscopy

Diagnostic colonoscopy may be required if there is a significant family record of colon tumors or possible symptoms. It might require a diagnostic colonoscopy if a person experiences symptoms such as bleeding from the rectum or in the feces, persistent abdominal pain, persistent alteration in bowel movements for an extended period, iron-deficiency anemia, and a history of polyps in the colon or cancer in family members.

2.3 Method

The effectiveness of various colonoscopy surveillance approaches relies on specific parameters that determine their viability in comparison to white light colonoscopy. Two important performance metrics are the colonoscopy withdrawal time, which shows how long it takes to remove the colonoscope, and the local intubation rate, which shows what proportion of the colon can be viewed [10]. There are five popular types of colonoscopy methods.

2.3.1 Virtual colonoscopy (VC)

This quickly evolving method uses data from computed tomography (CT) scans to produce 2D and 3D pictures of both the rectum and the colon. This technique is occasionally known as computed tomographic colonography [11]. Rather than employing the traditional approach, VC creates a picture of the rectum or colon using x-rays, and conventional colonoscopies are used to examine it. This method is favored due to its noninvasive nature, eliminating patient discomfort and obviating the need for sedation. Unlike standard colonoscopies that involve sedatives and may require a recovery period before normal activities can be resumed, virtual colonoscopy offers a more convenient alternative [12]. VC was introduced as a colorectal cancer screening procedure in the United States by the American Cancer Society, the American College of Radiology, and the U.S. Multi-Society Task Force for Colorectal Cancer. For the last decade, hospitals have extensively utilized this approach. Research conducted by Agha et al. revealed that virtual colonoscopy exhibited a sensitivity and specificity of 97 and 100%, respectively, in identifying polyps larger than 1 cm. Consequently, this approach has the capability to detect a greater number of lesions compared to conventional colonoscopy. The necessity for invasive procedures would decrease with the introduction of VC. Despite being less costly, this method can still result in false-positive outcomes, lowering sensitivity to 93%. A false positive will lead to more needless steps and processes [13].

2.3.2 Chromo-colonoscopy using dye-based techniques

In this method, a colon is sprayed with a dye solution. Applying this dye increases the likelihood of identifying nonpolypoid lesions, which increases the detection rate of adenomas [14]. Apart from the dye spray, this method uses a standard colonoscopy instrument. Various dyes are employed based on preference and intended objectives. These dyes fall into three main categories: contrast, absorptive, or reactive. Contrast dyes, such as indigo carmine, permeate irregularities and accumulate on polyps, enhancing visibility during the procedure [15]. Crystal violet is one example of an absorbent dye that penetrates epithelial cells and makes it easier to differentiate between tumors and infections. Absorptive dye requires initial treatment, such as mucus clearance from the mucosa wall, compared to contrast dye [16]. Responsive staining, such as Congo red, employs chemical reactions to draw attention to certain features inside the tissue. Indigo carmine is the most often used contrast dye because it is affordable, nonhazardous, and easy to use [17]. Unlike traditional colonoscopy, this kind of colonoscopy, which takes random specimens, permits targeted biopsies.

Compared to traditional colonoscopy, this method greatly increases the possibility of discovery because it can differentiate between lesions and polyps and normal mucosa. Wu et al. conducted a study demonstrating that the application of dye-based chromo-colonoscopy resulted in higher sensitivity (95%) compared to conventional colonoscopy. However, the sensitivity varied based on the type of dye utilized. The use of indigo carmine exhibited superior sensitivity compared to methylene blue (74%), but it also indicated lower specificity. Specifically, indigo carmine had a specificity of 91%, whereas methylene blue had a specificity of 92% [18]. The differences in the colors’ ability to help physicians distinguish tumors from their surrounding mucosa, which makes polyp identification simpler, may be the cause of the discrepancy in outcomes. The adoption of this technique has been inconsistent, likely due to a steep learning curve. In clinical use, it has not become a widely accepted alternative for conventional colonoscopy, in part due to the unpleasant and lengthy nature of dye application. Furthermore, some research indicates that some dyes, such as methylene blue, can be cancerous [16].

2.3.3 Electronic chromo-colonoscopy

Narrow band imaging (NBI), flexible spectrum imaging color enhancement (FICE), and i-scan digital contrast (i-scan) are the three primary forms of electronic chromo-colonoscopy. These methods all provide a mucosal contrast with the colon’s blood vessels. Among the three approaches discussed, NBI has been extensively studied. When compared to traditional colonoscopy, electronic chromo-colonoscopy typically has a sensitivity of 91%, meaning that polyps or lesions are less likely to be missed [19].

2.3.3.1 Narrow band imaging (NBI)

NBI is dependent on hemoglobin’s ability to absorb light, which accentuates the mucosa’s vasculature. However, the light source is filtered such that it only emits the green and blue bands of light, which represent the maxima of hemoglobin’s light absorption [20]. The absorption peaks of light in this method occur at 415 nm (blue light) and 540 nm (green light). The vascular mucosa has a combination of green and blue coloration that enhances the visibility of structures and patterns. This method allows for focused biopsies and can distinguish between malignant and benign cells, similar to dye-based chromo-colonoscopy. Interestingly, this method defines the boundaries of lesions without the use of dyes, which can be more convenient for individuals who are allergic to dyes in their bodies. In a 2014 study, the use of NBI for adenomas and polyp detection demonstrated a sensitivity of 98%, indicating its efficiency in detecting lesions, polyps, or adenomas. However, the accuracy of this technique, at 75%, is noticeably lower than that of a conventional colonoscopy [21]. Vişovan and his colleagues recently finished research that indicated elevated rates of polyp and adenoma detection. Numerous studies have been done on the use of NBI, and the bulk of the earlier studies have concluded that it is not a practical solution. Nevertheless, Olympus sells this technique that has been used in clinical settings [19, 22].

2.3.3.2 Flexible spectral imaging color enhancement (FICE)

White light colonoscopy is used in this approach; however, the final picture is digitally altered using algorithms based on spectra emission techniques to change the prominence of specific wavelengths. FICE incorporates optical filters and spectra-estimation technology to generate images from white light colonoscopy at various wavelengths [23, 24]. This method makes vascular and surface structures apparent through magnification, making it easier to distinguish between atypical and typical tissue development. Randomly selected single-wavelength images are designated to the colors blue, green, and red [25]. This enables the creation of an improved color image, utilized for structural and vascular enhancements. The technology includes 10 presets that can be customized further, offering a wide range of wavelength combinations. According to Lami and colleagues, FICE has a higher detection rate than white light colonoscopy, which suggests that it may be a more effective procedure for finding adenomas [26]. Osawa and colleagues conducted a study to explore the potential of FICE as a substitute for traditional colonoscopy. The research revealed that FICE demonstrated effectiveness in screening esophageal and gastric lesions characterized by high color contrast, yielding a notable sensitivity of 88% and specificity of 88% [27, 28]. Nevertheless, FICE has not been thoroughly investigated, preventing its clinical implementation, unlike NBI.

2.3.3.3 i-scan digital contrast

Similar to FICE, i-scan is a new technique that makes use of the pictures from white light colonoscopy. Using three distinct algorithm modes, the user may apply filters to a picture to improve tissue contrast through the use of an i-scan software [29, 30, 31]. One of the three functions focuses on surface enhancement, aiming to increase the distinction between light and dark areas. This results in improved visualization and a more thorough examination of the structure of the mucosal surface. According to Bowman and colleagues, surface augmentation makes it easier to identify the boundaries between pathological and normal mucosa. The polyp identification efficiency is increased by using this method. Enhancement of contrast is the second mode. By suppressing the wavelengths of red and green, this produces a blue-tint picture that improves the visualization of the mucosal surface’s depth [32]. The use of contrast enhancement is helpful not only in revealing abnormalities that might go unnoticed with exclusive reliance on white light colonoscopy but also in visualizing irregularities. The last mode, known as tone enhancement, involves limiting the red wavelength, thereby improving the visualization of subtle irregularities and the vascular structure within the mucosa. According to Cho and his colleagues, tone enhancement proves to be an effective tool for characterizing previously identified lesions [29, 33, 34]. In a clinical research, Hoffman and collaborators evaluated the efficacy of i-scan versus conventional colonoscopy. The findings from their research indicated a higher detection rate of polyps when using i-scan in comparison to conventional colonoscopy alone. While most studies incorporating i-scan also utilize other techniques, the majority of these combined approaches demonstrate enhanced sensitivity. Therefore, it appears that i-scan may enhance sensitivity, but its effectiveness is most notable when used in combination with other techniques [35].

2.3.4 Autofluorescence imaging (AFI)

The tissue of the colon may include fluorophores such as collagen, nicotinamide, flavin, and porphyrins. They release a naturally occurring fluorescent light that is sometimes referred to as autofluorescence (AF) light when stimulated by light (ultraviolet or short visible light). The light utilized for illumination is shorter in wavelength (500–630 nm) than the light generated by the AF, which results in a pseudocolor image on the colonoscopy display. The emitted fluorescence is contingent on the composition of tissues, the variety of fluorophores, their concentrations, metabolic rates, and spatial distribution. The distinctions in colors enable the AFI system to detect existing lesions. With the help of this approach, blue as well as green lights with wavelengths of around 450 and 550 nm, respectively, are produced by a color filter wheel in rotation. The interference filters built within the colonoscope allow the reading of AF light, reflecting green light onto the filter and eliminating blue light. During the colonoscopy operation, tumors show purple and normal mucosa appears green due to the interference filter. The user can distinguish between abnormalities and normal tissue thanks to this differentiation [29]. There has been research comparing AFI versus white light colonoscopy; however, a study from 2013 found no increase in the rate of detection with AFI [36]. Nevertheless, a 3-year-old study revealed that AFI with a transparent hood boosted polyp identification rates [37, 38].

2.3.5 Capsule colonoscopy endoscopy (CCE)

Initially presented in 2007 as a substitute for conventional colonoscopy, this device requires the patient to ingest a capsule to initiate the imaging process. Three collimated x-ray beams from a rotating source scan the colon as the capsule passes through. Rapid recovery is enabled by the photographic storage’s reliance on radio frequencies (RF) and wireless data transfer via a microcontroller. Within a few seconds, the system traces the 3D position and orientation of the capsule within the surrounding colon. Notably, the capsule features optical domes on both ends, providing a more comprehensive view of the lumen compared to conventional colonoscopy [39]. From these initial-generation gadgets, the capsule has undergone additional development. Presently produced in the United States by Medtronic, the second generation devices (CCE-2) contain cameras with a 172° wider field of vision, which results in a 354° field of view. In comparison to CCE-1, which has a 154-degree field of view, this one is significantly bigger. Presently, the CCE device has been employed to address incomplete colonoscopies, detect polyps, and examine inflammatory bowel disease. Incomplete colonoscopy may occur when only a portion of the colon is imaged, potentially resulting in missed lesions or polyps. VC is often employed in cases of incomplete colonoscopies to visualize large polyps and masses in the colon. However, an analysis of 14 studies found that CCE-2 is superior to both CCE and VC for polyp visualization [40]. Yung and colleagues conducted a review of multiple studies examining the efficacy of CCE and CCE-2 in detecting polyps. The findings indicated that for polyps smaller than 6 mm, CCE and CCE-2 demonstrated an overall sensitivity of 58 and 86%, respectively. Additionally, they exhibited overall specificities of 85.7 and 88.1% [41]. As a result, CCE-2 is more useful in the identification of polyps, and it excretes capsules at a somewhat higher rate than CCE. CCE is favored over virtual colonoscopy because of its superior detection rates and the potential adverse effects of x-rays on the human body. However, a notable drawback of capsule endoscopy is its time-consuming and labor-intensive nature that could impose challenges on clinic staff and patients alike [42].

2.4 Application

2.4.1 Colorectal cancer screening

Colorectal cancer initiates in the colon, the extended tube responsible for transporting digested food to the rectum and eventually out of the body. This cancer arises from specific polyps or growths in the inner lining of the colon. Healthcare providers employ screening tests to identify precancerous polyps before they transform into cancerous tumors. Screening colonoscopy offers potential benefits to patients in two ways. Primarily, it can identify and facilitate the removal of precancerous polyps. Additionally, colonoscopy has the capability to detect cancers at an early stage, increasing the likelihood of successful treatment compared to those found in more advanced stages. Given its ability to detect and remove polyps before they progress to cancer, colonoscopy appears to be an ideal screening tool [43, 44].

2.4.2 Gastrointestinal perforation

A gastrointestinal perforation is a severe condition necessitating immediate medical attention. Specific medical conditions and injuries can increase the likelihood of experiencing gastrointestinal perforation. However, with swift medical intervention, many individuals achieve a complete recovery. A colonoscopy is essential for providing interior images of the large intestine or colon [45].

2.4.3 Chronic colitis such as Crohn’s disease or ulcerative colitis

The digestive system becomes inflamed and irritated when an individual has Crohn’s disease. Abdominal discomfort, diarrhea, loss of weight, and rectal bleeding are possible symptoms. While this condition is lifelong and currently incurable, available treatments are generally effective in symptom management, enabling an active lifestyle. Colonoscopy is a commonly used diagnostic tool, involving the use of a colonoscope, a thin tube with a light and camera attachment to examine the interior of the colon. Additionally, the doctor might conduct a biopsy, extracting a tissue sample from the colon to check for signs of inflammation. Ulcerative colitis (UC) is a chronic condition characterized by inflammation and ulcers within the colon (large intestine). As a prevalent form of IBD, UC frequently leads to symptoms such as bloody diarrhea and abdominal cramping. In the diagnostic process, a colonoscopy is performed using a slender, flexible tube equipped with a tiny camera. The endoscope is inserted through the rectum by a healthcare provider to examine the interior of the colon and collect tissue samples for biopsy testing [46].

2.4.4 Colonic ischemia

Colonic ischemia is a condition that arises when there is partial or complete blockage of blood flow to the colon. Typically, the blockage occurs in one or more arteries that supply blood to the large intestine. Colonic ischemia can manifest either acutely, with a sudden onset, or chronically, developing gradually over time. This disorder is more prevalent in older individuals, particularly those with cardiovascular diseases or blood clotting disorders. Colonoscopy is a common diagnostic method for detecting ischemia. If there is suspicion of an issue in the colon, large intestine, or the lower part of the small intestine, a colonoscope is inserted through the rectum. Colonoscopy is particularly recommended for individuals who cannot undergo a contrast injection, especially those with allergies or kidney problems [47].

2.4.5 Ischemic colitis

Ischemic colitis is a form of colitis, involving inflammation in the colon, but it differs from other types as it originates in the circulatory system. The colon experiences reduced blood flow, leading to oxygen deprivation and triggering an inflammatory response. Without the restoration of blood flow, it may result in tissue death. In cases of tissue death or rupture in the colon wall, removal of the affected part may be necessary through colonoscopy. Bowel resection, which might involve a temporary or permanent colostomy, could also be considered [48].

3. Complications related to colonoscopy

There are many complications related to colonoscopy. Figure 2 displays the various complications related to colonoscopy.

Figure 2.

Complications related to colonoscopy.

3.1 Serious gastrointestinal colonoscopy complications

Several studies have examined the serious consequences of colonoscopies; the majority of these studies have concentrated on the risks associated with gastrointestinal bleeding or colonic perforation. Diverticulitis and postpolypectomy syndrome are two more severe side effects. At least 4 weeks after the colonoscopy, major consequences including gastrointestinal bleeding have been known to occur at delayed intervals. For this reason, it is important to monitor the rate of complications. Extensive research has focused primarily on investigating the possibility of colonic perforation. Despite being a potentially severe complication, its occurrence is infrequent, as indicated by findings from extensive studies, with reported rates generally below 0.3% and often less than 0.1%. On the other hand, the most prevalent serious complication is lower gastrointestinal bleeding, with reported risks ranging from 0.1 to 0.6% [49]. The degree of risk reduction in complications when employing colonoscopy for screening or surveillance purposes compared to diagnostic purposes remains uncertain. A comprehensive study carried out by the U.S. Preventive Services Task Force concluded that among mostly asymptomatic patients, the estimated incidence of significant consequences after screening colonoscopies was 2.8 per 1000 assessments [50].

3.2 Bowel preparation-related complication

Bowel preparation regimens fall into two broad categories: those based on electrolyte solutions with polyethylene glycol (PEG) and those without PEG, including sodium phosphate solutions. Although the sodium phosphate formulations with lesser volumes are usually well tolerated, there have been concerns expressed over the possibility of kidney damage with these regimens. Research on colonoscopies in healthy adults has indicated the occurrence of notable hypocalcemia or hyperphosphatemia with these preparations [51]. The possibility of acute phosphate nephropathy from calcium-phosphate crystal precipitation in the kidney is the most worrisome. Individuals who are dehydrated or old may be more susceptible to acute phosphate nephropathy. Additionally, using some antihypertensive drugs, such as diuretics, ACE inhibitors, or angiotensin receptor blockers (ARBs), may raise the risk if a person has hypertension. Although the exact risk is unclear, acute phosphate nephropathy is thought to affect fewer than 0.1% of people [52]. In a backward-looking investigation, Hurst and co-researchers identified acute kidney injury, characterized by a rise in serum creatinine exceeding 0.5 mg/dL, in 1.2% of patients within a year following colonoscopy. Compared to those who utilized PEG-based solutions, those who had undergone a sodium phosphate preparation had a greater incidence of acute renal damage [53]. It is not recommended to use sodium phosphate preparations in senior patients, people with pre-existing renal illness, or people who already have fluid or electrolyte imbalances, such as congestive heart failure patients. PEG-based treatments are thought to be safe for those with chronic renal disease, congestive cardiac failure, and electrolyte abnormalities because they do not significantly affect fluid balance. Nevertheless, due to the substantial volume of the required preparation, patients often find it challenging to tolerate [54]. Nausea and vomiting, along with a sense of abdominal fullness, are frequently experienced during the intake of large-volume preparations. Conditions such as vomiting-induced Mallory-Weiss tears, esophageal disruption, pulmonary aspiration, hypothermia, and cardiac arrhythmias are uncommon side effects associated with these preparations [55]. Imbalances in electrolytes are less frequent with PEG-based solutions in comparison to sodium phosphate preparations, as has been recorded.

3.3 Sedation-related and cardiovascular complications

Although they are rare, serious side effects from mild sedation during a colonoscopy might include hypoxia, respiratory depression, cardiac arrhythmia, hypertension, and vasovagal responses. In a meta-analysis of randomized studies for mild sedation, McQuaid and Laine discovered that patients getting midazolam alone had an 18% risk of hypoxemia, compared to those receiving midazolam plus a narcotic, who had an 11% risk [56]. Examining information derived from 174,255 colonoscopies within the Clinical Outcomes Research Initiative (CORI) database, Sharma and team identified a general incidence of cardiopulmonary complications post-colonoscopy at a rate of 1100 per 100,000 procedures [57]. The prevalent cardiopulmonary complications included transient hypoxia, bradycardia, hypotension, and vasovagal reactions. The possibility of having too many cardiovascular events within 30 days following a colonoscopy has raised more worries. When Warren and coworkers examined Medicare seniors’ risk of cardiovascular events after a colonoscopy, they discovered a slightly higher risk of events needing an ER visit or hospital stay than in a sample with similar age, gender, and comorbidities [51]. Arrhythmia emerged as the prevailing adverse cardiovascular occurrence. The heightened likelihood of cardiovascular events was particularly notable in individuals who underwent a polypectomy in contrast to matched counterparts who either did not undergo colonoscopy or underwent either screening or diagnostic colonoscopy. Conditions such as diabetes, stroke, atrial fibrillation, or congestive cardiac failure have been associated with a higher likelihood of cardiovascular events as compared to people lacking these underlying medical disorders. Nevertheless, there was no statistically significant difference in the risk of cardiovascular events between the groups that were matched and the individuals who were not undergoing a colonoscopy. Another trial using screening and surveillance colonoscopies, including individuals who were generally younger, did not find a greater chance of cardiovascular episodes.

3.4 Infection

Following colonoscopy, whether with or without polypectomy, a temporary presence of bacteria in the bloodstream happens in roughly 4% of procedures, with variability in the range of occurrence from 0–25% [58]. Inflammation stemming from conditions such as toxic megacolon, fulminant colitis, ulcerative colitis, Crohn’s flares, diverticulitis, and others may arise. Although isolated instances of infection subsequent to colonoscopy have been documented, there was no established direct causative connection with the endoscopic procedure. Moreover, there was no confirmed advantage associated with antibiotic prophylaxis. As a result, both the American Heart Association and ASGE currently discourage patients having colonoscopies from using antibiotic prophylaxis [59].

3.5 Mortality

Fatal incidents associated with colonoscopy, with or without polypectomy, have been infrequently documented. Out of 371,099 colonoscopies, a 2010 study found 128 recorded fatalities related to the procedure. The study encompassed both prospective research and retrospective examination of large clinical or administrative datasets. An overall unweighted mortality rate of 0.03% was the result of this [49]. While some investigation recorded death from all causes, and others restricted their analysis to mortality specifically related to colonoscopy, all studies documented mortality within 30 days following the procedure.

3.6 Miscellaneous complication

Severe appendicitis, incarcerated hernias, subcutaneous emphysema without perforation, intramural hematoma, and ischemic colitis are uncommon and infrequent problems related to colonoscopies. Instances of colonic explosions have been documented in patients undergoing electrocautery, especially those with inadequate bowel preparation, notably with mannitol preparations, although the latter are not presently in use [60]. While it is common to experience temporary bacteremia during a colonoscopy, antibiotic prophylaxis is not usually advised due to the rarity of bacteremia consequences such as infective endocarditis. Glutaraldehyde endoscopic disinfection may cause a chemical colitis if the endoscope is not completely cleansed before the start of the procedure.

4. Risk factors

A major risk factor for major gastrointestinal problems following a colonoscopy has repeatedly been demonstrated to be growing older. In contrast to patients aged 65–69 years, Gatto and colleagues observed that subjects aged 75–79 years old had a roughly fourfold higher risk of perforation [61]. The likelihood of colonic perforation, specifically, may be higher in females. This correlation may be explained by the finding that women often have more difficult colonoscopies than men do, possibly as a result of differences in pelvic anatomy and a greater frequency of previous pelvic procedures in women. In the Medicare population, the co-occurrence of concurrent conditions such as stroke, diabetes, atrial fibrillation, and congestive cardiac failure has been associated with an increased risk of major adverse outcomes; however, not all studies have shown this correlation [62]. The likelihood of complications significantly rises in procedures involving a polypectomy, especially when electrocautery is employed. Levin and co-researchers discovered a ninefold increase in the overall risk of serious complications in colonoscopies involving biopsy or polypectomy, although the risk specifically related to perforation did not show a significant increase. Furthermore, the risk of complications, predominantly gastrointestinal bleeding, escalates even more when multiple polypectomies with electrocautery are performed [63]. Complications may also arise from a biopsy alone. Previous research has indicated that hot biopsy, especially when performed in the proximal colon, may increase the risk of bleeding when polyps are removed [64]. While certain researchers propose that the experience and proficiency of endoscopists might impact the rates of complications, there is limited data to either support or contradict this notion. In Canada, the specific expertise of the endoscopist did not impact the chances of complications. However, endoscopists who performed fewer colonoscopies had a higher risk of complications compared to those who performed a higher number of procedures. It is worth noting that when considering only colonoscopies conducted by gastroenterologists, the volume of colonoscopies was not linked to the risk of complications [62]. Complications from colonoscopies may also be more likely in those taking clopidogrel or warfarin [65]. For example, Hui and colleagues found that the risk of postpolypectomy bleeding was higher when warfarin was used, even after considering factors such as the age of the patient, polyp position and dimensions, polypectomy technique, and underlying renal impairment. On the other hand, there is no evidence that taking aspirin or nonsteroidal anti-inflammatory drugs increases the likelihood of postpolypectomy bleeding [66]. According to the guidelines from the American Society of Gastrointestinal Endoscopy, individuals having endoscopic treatments may not necessarily need to stop taking aspirin or nonsteroidal anti-inflammatory medicines. The underlying indications for clopidogrel’s use as well as the potential dangers associated with the scheduled surgery must be taken into consideration while making decisions regarding stopping the medication.

5. Management of complications related to colonoscopy

5.1 Patient management

Any patient who encounters a problem needs to be attended to right away by skilled medical professionals, who frequently comprise a multidisciplinary team including surgeons, interventional radiologists, and endoscopists. Typically, surgical consultation is recommended as well. Patients should be admitted right away to an institution that is prepared to handle problems that do not respond to urgent colonoscopic care. These complications may need medical, surgical, radiologic, or other therapies [67]. While many complications in medical procedures are inevitable, some do result from errors in healthcare. In recent times, there has been a growing focus on providing patients with information about medical mistakes. These mistakes are described by the Institute of Medicine as either the failure to carry out a planned action as intended or the use of an incorrect plan to achieve a goal. Studies indicate a disparity between patients’ expectations regarding the disclosure and apology for medical errors and the actual proficiency of physicians in effectively communicating such errors. Consequently, numerous institutions are adopting policies mandating the disclosure of medical errors. Since 2001, the Joint Commission has enforced a requirement for hospitals and healthcare organizations to disclose “unanticipated outcomes” as an integral part of their accreditation standards [68]. Quality improvement initiatives should make targeted attempts to recognize adverse events occurring within 30 days following colonoscopy. Thorough evaluations of all potential issues should be carried out and deliberated among healthcare professionals in a structured environment focused on improving quality, such as a death and morbidity conference. This platform should facilitate open discussions among physicians about the procedure, enabling the identification of any aspects of care that could be enhanced. Additionally, these conferences serve to pinpoint systemic issues that, when addressed, can contribute to an improvement in the overall quality of care [69]. Both the patient group and the kind of operation being done have an impact on the likelihood of problems.

5.2 The function of specialized organizations is to minimize complications

Specific risk factors for problems are hard to identify for a particular endoscopist or small team of endoscopists because of the uncommon nature of problems and the diverse patient demographics. As a result, although each endoscopist is accountable for their own patient care, the entire group of endoscopists is collectively responsible for setting practice guidelines that maximize the advantages of colonoscopy and reduce the risk of damage to any patients. One example is the controversial and evolving topic of managing antithrombotic medications (such as warfarin, clopidogrel, and aspirin) during the time of a colonoscopy. Professional associations for gastroenterology have updated their guidelines in response to new data on the risks of blood clot-related events versus the hazards of bleeding problems from discontinuing antithrombotic medical care [70]. Specialized societies in gastroenterology have proactively engaged in educating their members about recognized issues and the corresponding corrective measures. They have also been involved in formulating and revising guidelines for the reprocessing of endoscopes and associated equipment. It is essential for these specialty societies to persist in promoting rigorous standards for endoscopist training and supporting ongoing research aimed at preventing complications arising from colonoscopies [71]. Patents related to the colonoscopy are given in Table 1.

Sr. no	Title	Patent number
1	Methods, systems, and media for simultaneously monitoring colonoscopic video quality and detecting polyps in colonoscopy	US10861151B2
2	Kit comprising an osmotic laxative and a stimulant laxative for preparing the colon for virtual colonoscopy	EP1976520B1
3	Hydro-colonoscopy combination system	US20130245380A1
4	Crohn’s disease assistant diagnosis system and method under a kind of colonoscopy based on deep learning	CN109615633A
5	Ulcerative colitis assistant diagnosis system and method under colonoscopy based on deep learning	CN109447987A
6	Edible semi-solid composition for use in patients undergoing endoscopy including colonoscopy	US20190298757A1
7	Method and apparatus for real-time detection of polyps in optical colonoscopy	EP3479348B1

Table 1.

Patent search analytical report.

6. Conclusion and future scope

Artificial intelligence (AI) is becoming more widespread, and its application to healthcare is developing quickly. AI is being investigated widely in the field of cancer screening to help interpret imaging tests such as mammography for breast cancer and colonoscopy for colorectal cancer. The overall number of adenomas found did increase as a result of the screening procedure’s implementation of computer-aided diagnosis (CAD). However, the main cause of the increase was the discovery of much smaller growths, which are less likely to become cancer. With the development of imaging technologies, there is a possibility that the number of small adenomas detected would rise. This could potentially harm the cost efficiency of colonoscopy by raising the costs related to polypectomy and pathology, without necessarily enhancing its effectiveness. A possible strategy in addressing this advancement is to overlook small adenomatous lesions, yet the inherent capability of colonoscopy lies in its ability to identify and remove precancerous lesions simultaneously. Another option would involve identifying and eliminating small adenomas, coupled with broadening the category of adenomas deemed low risk. This could lead to longer intervals for postpolypectomy monitoring, possibly up to 10 years or more, particularly if the examination includes thorough removal of even the tiniest and flattest lesions. The expense associated with evaluating pathology for very small polyps is considerable, and the primary purpose of pathologically assessing polyps measuring 5 mm or less is to determine postpolypectomy surveillance intervals. If effective methods for examining polyp tissue in actual time were developed, it would be possible to remove or cut out small polyps and discard them. Afterward, follow-up monitoring after polyp removal could depend on immediate endoscopic assessment of tissue characteristics. The significant financial benefits from this progress would enhance the overall cost efficiency of colonoscopy and polypectomy in comparison to other imaging methods [72]. The extent to which anesthesia specialists participate in colonoscopy sedation will significantly influence the overall cost-effectiveness of colonoscopy in comparison to alternative diagnostic imaging strategies. In the coming years, colonoscopy is expected to be the favored diagnostic method for people with positive screening results and those displaying symptoms strongly suggestive of colorectal cancer. These symptoms may include hemochromatemia, deficiencies in iron, and melena, particularly when an upper endoscopy reveals no abnormalities [73]. Hence, the exploration of any potential progress in addressing the factors contributing to interval cancers is deemed worthwhile. As mentioned previously, the widespread adoption of strategies to enhance the effectiveness and safety of colonoscopies, coupled with advancements in colonoscope technology, is expected to strengthen the role of colonoscopy as a leading primary screening method compared to emerging imaging technologies. Beyond readily attainable improvements, it is important to note that colonoscopy is evolving, and innovations in imaging and potential insertion platforms could further enhance its efficacy and cost-effectiveness [74].