Surgical Reconstruction of the Temporomandibular Joint

Abstract

This chapter provides a comprehensive overview of the temporomandibular joint (TMJ), including its embryonic development, anatomy, and physiology. It also discusses techniques for management and reconstruction in TMJ disorders, such as TMJ ankylosis (in children and adults), first arch syndromes, and chronic and acute TMJ dislocation and subluxation.

1. Introduction

In 1962, Melvin Moss introduced the functional matrix theory, which proposed that the growth of the face is due to functional demand of the periosteal matrix of the facial skeleton. In 1771, John Hunter was the first to nominate the condyle as the primary growth center of the facial skeleton in his book The Natural History of the Human Teeth [1]. Moss’s theory was more accepted for many years, but we believe the true nature of the growth of the facial skeleton lies within a combination of both theories [2].

2. Embryonic development of the TMJ

Much research has been carried out to understand the formation and development of the mandible and TMJ. The mandible develops from the first pharyngeal arch, which is formed from the neural crest that originates in the mid and hind brain of neural folds. The TMJ develops from mesenchymal condensation of cells, these cells separating between development of squamous portion of temporal bone from condylar cartilage which form the dorsal surface of developing condyle. The early movements of these cells to form the primary TMJ occur at embryonic age 4 months.

Three phases of TMJ development have been reported. The first phase is called the blastemic stage, which occurs during weeks 7–8 of embryonic development. Organization of the condyle, articular disc, and capsule begin at this stage. The second phase is the cavitation stage, during which the inferior joint cavity begins to form at embryonic age 9–11 weeks. This stage involves initial formation of the inferior joint cavity (week 9) and the start of condyle chondrogenesis (week 11). Organization of the superior joint cavity also begins in week 11. The third phase is the maturation stage (after 12 weeks of embryonic development).

The two slits of the joint cavities and the intervening disc form at 12 weeks of embryonic life and the mesenchyme around the joint forms the capsule and the synovial fluid [3].

3. Anatomy and physiology of the TMJ

The TMJ is a synovial joint, unique among all other human body joints because it is the only mobile joint of the craniomandibular part where the mandible articulates with the skull base. It is a highly specialized joint consisting of two compartments. The articular part is covered by fibrocartilage, while other joints are covered by hyaline cartilage. The jaw bones that articulate with it carry teeth and its work is synchronized on both sides like that of the eyes. The TMJ allows for more than 2000 hinge and sliding movements per day in both active masticatory and passive movements like talking, swallowing, and yawning. It is one of the most active joints in the human body.

The ligaments of the TMJ are strong and tough surrounding the condyle and glenoid fossa. There are two types: primary ligaments (temporomandibular ligaments) consisting of outer oblique and inner horizontal ligaments, and minor ligaments (styloid-mandibular and sphenoid-mandibular ligaments) that work as supportive tissue to the capsule. Other accessory ligaments define the border movements of the TMJ.

The disc or meniscus consisted from 4 parts anterior band attached to upper fibers of lateral pterygoid muscle and the lower part of the lateral pterygoid of strong muscle fibers were attached to condylar fossa. The intermediate zone is the area between the anterior and posterior bands, which are positioned normally on the head of the condyle in a closed mouth.

The posterior part of the disc is an elastic recoil fiber attached to the posterior part of the capsule. When the condyle moves forward the posterior band moves with it. Any disorganization between the two parts of the muscle fibers and failure of the posterior band to move with the condyle can cause internal derangements and clicking in the jaw.

TMJ function is controlled by a complex series of reflexes for muscular movement of mastication.

The TMJ consist of two compartments separated by the meniscus: the superior compartment and the inferior compartment. The synovial joint is located in front of the auditory meatus.

Condylar movements are unique. The condyle can move, swing, and rotate within the glenoid fossa, but its movements are limited by ligaments and surrounding muscles.

Synovial lining of the capsule form Ville in both upper and lower joint cavity to secrete fluid for lubrication and the synovial membrane provide sera-mucinous fluid for lubrication and protein for nourishment of the fibro-cartilage part of the joint.

One of the most important functions of synovial fluid that in sudden load exerted on the TMJ, lubrication occurred by squeeze film, sufficiently viscus to be squeezed slowly to persist the long enough to support the load excreted in a short time under sustained high load. The nature of lubrication was a boundary rubbing take place between the layers of large molecules absorbed in the cartilage surface and failure of lubrication causes great damages to cartilaginous part of the TMJ [3].

4. Development and growth of the TMJ

The mandible is formed and developed as a membranous bone originating from mesenchymal tissue [4].

4.1 Theories governing the growth of the facial skeleton

In his 1771 book The Natural History of the Human Teeth, John Hunter stated that growth of the mandible occurred as result of activation of the growth center in the condyle [1].

The functional matrix hypothesis introduced by Melvin Moss in 1962 proposed that growth of the mandible and facial skeleton occur due to functional demand of the periosteal matrix of the muscles of mastication [2].

The author believes that the true nature of the growth of the facial skeleton lies within a combination of both theories. To support his hypothesis, the author performed experiments on newly born rabbits in which he excised their condyles. After three months the rabbits showed severe deformities of their lower jaws and their mandibles were twisted to the affected side.

4.2 Functional activity of the TMJ

There are two types of movements in the TMJ: passive and active. Passive movements are used for speaking, laughing, yawning, singing, swallowing, and smoking. Active movements are used for the masticatory process, which is coordinated by four receptors.

Ruffini receptors function as static mechanoreceptors that position the mandible. Pacinian corpuscles are dynamic mechanoreceptors that accelerate movements during reflexes. The Golgi-Mazzoni corpuscles function as static mechanoreceptors for protection of themselves.

4.3 Histology of newly growing condyle

A newly growing condyle consists of four layers. The first layer is the articular fibrocartilage layer, the second layer consists of several zones of small, round mesenchymal stem cells, the third layer consists of an immature chondrocyte and newly formed osteoblasts, and the fourth layer consists of the mature trabecular bone with bone marrow in between and osteoblasts.

4.4 Reconstruction techniques for TMJ diseases

4.4.1 TMJ ankylosis in children

TMJ ankylosis is a painful disease that limits the opening of the mouth due to fusion of the condyle with the glenoid fossa in the skull base. Difficulties in mastication and swallowing are obvious signs.

There are three types of TMJ ankylosis: fibrous, bony, or a combination of both.

Facial deformity is obvious; the mandible is twisted to the affected side with short ramus and bowing of the lower border on the affected side, making a depression or concavity called the antegonial notch. This notch is a diagnostic sign of ankylosis with hyperplasia of the coronoid process. The floor of the mouth is underdeveloped and the tongue is in the retro position with changes and deformity of the upper respiratory tract, hyperplasia of epiglottis, and deformity of the larynx. The trachea is deviated and shifted to the affected side and the larynx is positioned more anterior.

These changes cause great difficulties in intubation during anesthesia by blind intubation and thus anesthesia should be done via guided endoscopic tube. With difficulties in intubation, a tracheotomy might be indicated.

The cause of this disease is mainly trauma to the chin in childhood, transmitted through the long access of the ramus to the condyle.

The condyle is a spongy type and vascular in children with short nek, the traumatic injuries to the condyle was crushing the condyle with fragmentation of the meniscus and damages to cartilaginous part of the TMJ.

Bleeding inside the joint causing hemarthrosis and the trauma may extend to the base of skull causing injuries to petrous bone and sagittal sutures of the base of skull the quelea for that was callus formation in the base of skull changing the length of transverse axis and longitudinal axis of the skull base.

Bleeding that occurs due to injuries to petrous bone of skull base, come out with CSF from the ear due to rupture of tympanic membrane. This type of case should be considered a head injury case and should be managed as such.

Surgical management of ankylosis in children is quite different from that in adults where the deformity of the facial skeleton already exists and growth is diminished.

In children, our choice is to use the Kummoona chondro-osseous graft for reconstruction of the TMJ after excision of all ankylosed bone with excision of hyper elongated coronoid process and reattachment of all muscles surrounding the ramus [5].

The chondro-osseous graft is harvested from the iliac crest. The length of the graft is between 4 and 5 cm and is covered by cup of 1-cm cartilage and small amount of muscle to work as the meniscus.

We approach the TMJ via modified incision starting from the periauricular region and going up the temporal region as a full-thickness fascio-cutaneous flap.

The dissection begins behind the temporalis muscle, from the posterior fibers of the temporalis muscle as a full-thickness Kummoona fascio-cutaneous flap and dissected down to the capsule of the joint. An L-shaped incision is made in the capsule to expose the ankylosed joint.

After decortication of both bone graft and ascending ramus, the graft is inserted via submandibular incision and fixed after positioning the head of the graft inside the glenoid fossa covered by muscle fibers from the iliac crest.

The graft is fixed firmly to the posterior side of the ramus using soft stainless-steel 0.5-mm wire in three points as rigid fixation to prevent any movement of the graft during function.

The aim of the chondro-osseous graft is to restore the growth potential of the mandible and midface with full functional activities required from the TMJ.

We ask the child to chew food after 3–4 days to obtain more growth by functional demand of the periosteal matrix, according to the functional matrix theory [2].

This technique has also been applied to treat first arch syndrome and hypoplasia of the condyle in children.

4.5 TMJ ankylosis in adults

TMJ ankylosis in adults can be managed using a two-part chrome–cobalt prosthesis developed by the author [6, 7]. This prosthesis is used in adults because growth of the face has already completed and thus there is no place for a chondro-osseous graft.

Before its application in humans, the prosthesis was used to replace the TMJ of Macaca monkeys in experiments carried out at the Royal College of Surgeons of England in 1975–1978.

The prosthesis was tested after animal scarified; the histology of the ramus carrying the shaft of implant was done by (H&E), a nice granulation tissue was formed and healthy fibroblasts were nicely formed and surrounding the prosthesis and the orientation of fibrous tissue fibers by the effect of masticatory process. Ground sections and microradiographs were also done to prove the biological viability of the prosthesis and proper orientation of the prosthesis shaft of the lower prosthesis. This TMJ prosthesis allows for full functional movements, including lateral excursion movements [7].

In our research, we found that a wide band of fibrous tissue was formed between the upper and lower parts of the prosthesis. This band prevented rubbing of metal ions between the parts, which can cause microthrombi to develop in the joint and induce necrosis and failure of the prosthesis [6, 7].

4.5.1 Reconstruction of hypoplasia of the condyle and first arch syndrome

Hypoplasia of the condyle in children can occur as result of intrauterine trauma to the condyle or trauma during birth or early childhood. The ideal technique for treating hypoplasia of the condyle is the chondro-osseous graft [8].

4.5.2 Management of first arch syndrome

First arch dysplasia syndrome or hemifacial microsomia is a congenital disease caused by early embryonic occlusion of the stapedial artery, the nutrient vessel of the first and second arches. There are three types of first arch deformities: mild, moderate, and severe.

The mild form is characterized by slight deformity of the ear and presence of small Tages in front of the ear with underdeveloped mandible, condyle, and masseter muscle. The condyle might be absent, but abnormal formation of bone simulating the condyle usually double with receding chin was observed.

Moderate disease is characterized by microsomia in the affected side with slight deformity of the mandible, absence of the TMJ and upper part of the ramus, deformity of the ear, and small Tages in front of the ear as remnants of Meckel’s cartilage.

The severe form is characterized by wide microsomia, severe cleft in the angle of the mouth, severe deformity of the mandible, and absence of the TMJ, the upper part of the ramus, glenoid fossa, zygomatic root of the temporal bone, and the ear.

The management of these complicated cases requires expert surgical skills. The first step is to reconstruct the zygomatic root of temporal bone via bone graft harvested either from the ilium or rib. The glenoid fossa is reconstructed via cartilage graft taken from the patient’s unaffected ear, followed by reconstruction of the cleft of the angle (commissuroplasty) by measuring the upper lip from midline to the angle of the mouth on the normal side. This measurement is applied on the cleft side with excision of skin access. Reconstruction begins with closure of the oral mucosa and bringing the orbicularis muscle and surrounding muscle to modules. Finally, the overlying skin is closed.

In the second step, the platysma muscle flap is mobilized a superiorly based muscle platysma flap from side of the neck to reconstruct the atrophied masseter muscle (Kummoona Platysma Muscle Flap). After a few months, the TMJ is reconstructed via chondro-osseous graft harvested from the iliac crest because the bony graft requires bulky muscle to overlap the graft for nourishment.

The chondro-osseous graft was designed for reconstruction of the TMJ during the growth period at age 4–6 years for restoration of the growth of the mandible and midface.

The graft contains mesenchymal stem cells responsible for growth, repair, and remodeling of the TMJ before reconstruction of the ear, chin reconstruction by Sialastic implant as genioplasty, bone grafting in this area might showed resorption.

The final stage of reconstruction of the first arch is to reconstruct the ear and correct occlusion via orthodontic treatment. Osteotomy or distraction techniques may be required for correction of jaw deformities [5, 9].

4.6 TMJ dislocation and recurrent subluxation

Acute dislocation of the TMJ is always associated with pain and spasm of masseter, temporalis, and internal pterygoid muscles, leading to trismus and preventing return of the condyle to the glenoid fossa [10]. It occurs when the condyles suddenly jump out of the glenoid fossa ventral to the articular eminence and become locked anterior and superior to the articular eminence. It can result from extreme opening of the mouth, for example, during extensive dental work or yawning.

Chronic dislocation typically results from untreated TMJ dislocations, and the condyle remains displaced for an extended period. It occurs less often after trauma. Both sides of the condyle slide on articular eminence ventrally to the infratemporal fossa. In chronically dislocated unreduced condyle, the capsule becomes fused and adheres to the infratemporal fascia.

Risk factors for dislocation includes weakness of the joint capsule, anatomic aberration of the joint, or injuries to associated ligaments.

Subluxation of the TMJ is an excessive abnormal excursion of the condyle secondary to flaccidity and laxity of a capsule or a condition where the condylar head moves anterior to the eminence on wide opening of the mouth. In this case, the mouth can be closed again easily but slowly.

Acute subluxation or dislocation is always associated with pain due to presence of intra-articular effusion and muscle spasm.

Chronic recurrent dislocation or subluxation is characterized by the condyle sliding over the articular eminence and catching briefly beyond the eminence before returning to the glenoid fossa.

The pathogenesis of dislocation and recurrent subluxation secondary to weakness or laxity of the capsule has been attributed to trauma or abnormal chewing habits movements. It is found more frequently in people with general joint laxity (Ehlers-Danlos syndrome, Marfan syndrome, and juvenile rheumatoid arthritis), in older persons with laxity of ligaments, weak muscles, and bone resorption, and individuals with internal derangements of the TMJ or with occlusal disturbance. Other predisposing factors include prolonged opening of the mouth during dental treatment/examination or during general anesthesia or bronchoscopy.

In countries like Yemen, Sudan, Somalia, and South Arabia, some TMJ disorders can be attributed to khat chewing. Khat is a plant found in Southern Arabia and East Africa known for its stimulant effects. Khat chewing is a social tradition. Daily chewing of khat produces an excessive load on the TMJ, changing its normal excursive hinge masticatory movements to habitual rotatory movement, leading to osteoarthritic changes including atrophy of the articular eminence, shallow glenoid fossa, and lax capsule and ligaments of the TMJ. The instability of the lower jaw during speech is due to the effect of khat on the brain stem. The plant exhibits amphetamine-like action and users become very talkative under its influence.

4.6.1 Management of TMJ dislocation

There are many methods for reducing dislocation of the TMJ, the most common of which is the Hippocratic method. This method involves the practitioner standing in front of the patient and placing a gloved thumb on the posterior lower molars bilaterally with fingers wrapped laterally around the mandible. Then, the practitioner pushes the jaw downward and backward to ease it back into the glenoid fossa.

Other techniques involve injecting sclerosing agents into the capsule or using autologous blood. These methods are mostly no longer used because they can cause damage to some vital structures of the joint and pain during the procedure and postoperatively.

We propose a new technique, in which the practitioner grips the patient’s lower jaw from behind and using the angle of lower jaw as pivot with slight rotation on one side immediately the condyle return to its normal position in the glenoid fossa, and immediate return of the condyle in other sides to glenoid fossa. The angle of the jaw mobilizes as a pivot by rotating the mandible in one side, immediately the side reduced and followed by other side [10, 11].

4.6.2 Management of TMJ subluxation

The ideal surgical technique advocated by the author for treating chronic recurrent subluxation and dislocation involves reinforcing and supporting the weak lax capsule with an inferiorly based, finger-shaped temporal fascia flap for reconstruction of the lateral and anterior walls of the capsule.

With reconstruction of the zygomatic root of temporal bone just in front of the articular eminence by creating an ostectomy in 45 degrees towards the joint and impacted a piece of bone from iliac crest of about 1.5 cm length and 1 cm width, it works as an obstacle for forward movement of the condyle [9, 10].

4.7 TMJ osteoarthritis

Osteoarthritis is a degenerative disease of aging that causes more severe symptoms in weight-bearing joints like the ankles and hips. It usually affects the TMJ in the early stages before it spreads to other joints of the body. TMJ osteoarthritis is characterized by a breakdown of the articular fibrocartilage layer with architectural changes in the associated bone and damage and degeneration of synovial tissue causing pain in the joint.

X-ray examination of the TMJ shows osteophytes, lipping, and cyst-like lesions (Ely’s cysts) with flatting of the articular layer. In the later stages, X-ray may reveal erosion of the condyle articular surface.

In advanced disease, the articular cartilage becomes less elastic with erosion of the surface of the condyle associated with vertical cleft or crack in the subchondral bone.

Reparative attempts of the joint at the periphery of the cartilage result in formation of osteophytes, lipping, and changes in the surface contour of the articular surface [3].

4.7.1 Management of TMJ osteoarthritis

In mild cases with pain and difficulty of mastication, my colleagues and I administer the intra-articular steroid methylprednisolone (injection of 80 mg 2 ml) to the superior and inferior compartments of the joint. We repeat this technique three times at two-week intervals.

In severe cases, surgical exploration of the TMJ is applied by full thickness fascio-cutaneous flap from the periauricular area with an extension to temporal region as? Flap. An L-shaped incision is made in the capsule to expose the condyle.

Irregularities of the condyle are removed by a pear-shaped surgical bur for removing the abnormal osteophyte, lavage of the joint, and inserting a sialastic implant shaped like the meniscus to prevent any friction between the glenoid fossa and the condyle.

4.8 TMJ dysfunction

TMJ dysfunction involving clicking of the jaw with or without pain is more prevalent in women than men. Jaw clicking is due to lack of coordination between movement of the disc and head of the condyle caused by hyperactivity of strong lower muscle fibers of the lateral pterygoid muscle with upper fine muscle fibers that attach to the anterior part of the disc. Other causes include irregularities in teeth position and occlusion disturbance. In severe cases, it may be associated with muscle spasm, which can limit mouth opening, deviate the jaw, and cause pain.

Radiological examination can be conducted via arthrography by injecting radiopaque material into the lower compartment of the TMJ to demonstrate reversible or irreversible disc movement and displacement of the disc or inferior-medial movement of the meniscus. Injection of radiopaque material to lower compartment of the TMJ can demonstrate disc perforation.

MRI has also been used to study changes in the head of the condyle and disc movement; however, MR is used mainly for viewing soft tissue of the TMJ.

Management of early cases of TMJ dysfunction with jaw clicking involves construction of a bite raising appliance to raise the bite or mouth opening between 2 and 3 mm to obtain proper relation between the head of the condyle and the disc where the posterior band of the disc cited on the top of the condyle. The patient should wear the bite raising appliance at night. The night bite appliance was very unsuccessful method for management of TMJ dysfunction. Correction of occlusion by orthodontic treatment should be done before construction of the bite raising appliance or at the same time.

The patient should be advised not to chew hard food or gum, to avoid yawning, and not to open their mouth more than.

We prescribe an anti-inflammatory medication and muscle relaxant to relieve muscle spasm and pain in the joint for one week.

Botulinum toxin A (Botox-A) has been used to relieve the hyperactivity of lower fibers of the lateral pterygoid muscle. It has shown some efficacy in clinical studies involving female patients. We do not recommend blood injection to the joint because it can cause damage to the cartilaginous part of the TMJ (Figures 1–7).

Figure 1.

Hippocratic technique for reducing dislocated condyles.

Figure 2.

a. John Hunter in his book the natural history of the human teeth stated that the condyle is a primary growth center. b. section of a newborn’s condyle showing active mesenchymal stem cells. c. newly born rabbit with jaw and facial deformity three months later due to excision of condyle and prove to be a growth center.

Figure 3.

a. A five-year-old female with ankylosis of the left TMJ. b. tomography of the left ankylosed TMJ. c. one year after reconstruction of the TMJ by chondro-osseous graft restoring normal face and normal mouth opening. d. tomography of the TMJ showing normal condyle movement created by chondro-osseous graft.

Figure 4.

Composite of four photos showing an 18-year-old man with ankylosed TMJ. First photo is preoperative and shows limited mouth opening. Second photo shows Kummoona two-part prosthesis replacing the TMJ. Third photo shows xerography X-ray of the jaw demonstrating the two-part prosthesis replacing the TMJ. Fourth photo shows the patient after 10 years with normal mouth opening.

Figure 5.

a. Baby born with first arch syndrome treated with distraction techniques with poor results. b. photo showing same child at age 4 years. c. CT scan of female child showing missing ramus and zygomatic arch of temporal bone. d. two-year postoperative photo after series of operations.

Figure 6.

a. A diagram showing design of Kummoona fascial temporal flap inferiorly based for reconstruction of lateral and anterior walls of the capsule of TMJ and site of ostectomy anterior to articular eminence of the joint. b. diagram showing temporal fascial flap rotated and used for reconstruction of the capsule and bone graft impacted in the site of ostectomy. c. photo showing temporal fascial flap mobilized to reconstruct the capsule. d. CT scan showing dislocation of the condyle. e. CT scan showing bone graft anterior to articular eminence and working as obstacle for forward movement of the condyle.

Figure 7.

a. Young woman with acute dislocation of the condyle. b. X-ray OPG showing dislocation of the condyle. c. photograph showing normal face after immediate reduction of dislocated condyle by Kummoona manual technique. d. X-ray OPG showing the condyle in the glenoid fossa after reduction.