Temporomandibular disorders. Part 3. Surgical treatment

Australian Dental Journal 1996;41:(1):16-20 Temporomandibular disorders. Part 3. Surgical treatment George Dimitroulis, MDSc (Melb), FDSRCS (Eng), FF...
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Australian Dental Journal 1996;41:(1):16-20

Temporomandibular disorders. Part 3. Surgical treatment George Dimitroulis, MDSc (Melb), FDSRCS (Eng), FFDRCS (Irel)" M. Franklin Dolwick, DMD, PhDt

In this, the third article in the presented. Key womls: Temporomandibular joint, surgery, arthrotomy, arthroscopy, arthrocentesis.

(Received for publication January 1994. Accepted June 1994.) I

Introduction Surgery of the temporomandibular joint (TMJ) plays a small but nonetheless important role in the management of temporomandibular disorders (TMD). The literature has shown that about 5 per cent of all patients undergoing treatment for T M D require surgical intervention.' There is a spectrum of surgical procedures currently used for the treatment of T M D ranging from the simple arthrocentesis and lavage to more complex open joint surgical procedures. The success of surgery is largely dependent on appropriate case selection. Each surgical procedure has strict criteria for which cases are most appropriate. It is often necessary that surgery is fully backed up by continuing non-surgical therapy, both prior to and after the operation, so that the greatest potential for success is achieved.

*Former Clinical Fellow, Department of Oral and Maxillofacial Surgery, College of Dentistry, University of Florida. +Professor and Chairman, Department of Oral and Maxillofacial Surgery, College of Dentistry, University of Florida. 16

TMJ surgical anatomy Compared with most other articular joints of the human body, the temporomandibular joint is unique in two ways: firstly, the articular surfaces are composed of fibrocartilage rather than hyaline cartilage, and secondly, the TMJ cannot function independently but only together with the TMJ on the opposite side. It is a ginglymo-arthrodial joint, which implies it has a hinge and sliding motion. That is to say, the TMJ is capable of rotation and translation which are the two basic movements required for normal mandibular opening. It is this type of functional movement that surgery aims to restore. A thorough appreciation of the local anatomy of the TMJ is mandatory for all surgical procedures involving the joint. Damage to important structures will most likely leave the patient with physical disabilities that will compound their original problem and render any further treatment inherently more difficult. The TMJ serves as the articulation point of the mandible to the cranial base. The glenoid fossa and articular eminence provide the articulating surface of the cranial base, or more specifically, the temporal bone. The condylar process of the mandible consists of a head, which is widest in the medio-lateral direction, and is attached to the ascending ramus by a relatively thin neck, to which the lateral pterygoid muscle is attached. Essentially, the condylar process is the key to the form and function of the mandible. Therefore, it must be carefully considered that any small physical changes that may occur in the joint, whether from disease, trauma, or surgery may have a considerable adverse effect not only on the occlusion but also on the entire form and function of the stomatognathic system. Within the joint itself, a dense fibrous disc, or meniscus, divides the joint into two compartments, that is, the superior and inferior joint spaces. Synovial fluid is secreted by synovial tissues at the edge of the articulating surfaces, and the joint complex is enclosed by a capsule which is reinforced by surrounding ligaments. Australian Dental Journal 1996;41: I .

From a surgical standpoint the superior joint space is the most accessible to operative procedures and hence is where the majority of intra-articular surgical procedures are undertaken. The disc is essentially the focus of the majority of intra-articular TMJ surgical procedures, mainly due to its central role in the pathology of internal joint derangement.’ The condylar head is particularly important in degenerative joint diseases whilst the articular eminence may be considered for surgery, particularly where mechanical interferences are involved. The lateral pterygoid muscle also has an important anatomical and functional role in the TMJ complex and may occasionally be considered for surgery.’

Indications for TMJ surgery Indications for TMJ surgery are somewhat controversial, since it has long been the belief that surgery is a radical form of treatment. If the goal is to achieve maximum improvement in symptoms with minimal morbidity, then surgery does have a very useful role in the management of TMD, particularly in cases which have remained refractory to a multitude of non-surgical treatment modalities over an extended period of time. Basically, there are obvious indications for TMJ surgery, and there are not so obvious indications. The most undisputed application for TMJ surgery is found in the management of the least common TMJ disorders, such as ankylosis, growth disorders, recurrent subluxation, infections and neoplasia. There is little doubt that surgery for these uncommon TMJ disorders remains the mainstay of treatment. Unfortunately, for the more common disorders such as internal derangement, degenerative joint disease (i.e., the arthritides) and trauma, the indications for surgery are less clear and often dependent on the individual clinician. For these situations many clinicians have adopted the policy of determining the need for surgery by the degree of disability suffered by the patient, in conjunction with the degree of improvement derived through nonsurgical treatment modalities. Therefore, a patient with degenerative joint disease, for example, who is incapacitated to a point where work and relationships are severely disrupted and who does not improve with non-surgical treatment over a nominal period of time, may be an appropriate candidate for surgical treatment. Clinical indications for TMJ surgery are relative rather than absolute and the following guidelines are used by the latter author (MFD):4,5 1. Where the T M D is refractory to appropriate non-surgical therapies. 2. Where the TMJ is the source of pain andor dysfunction that results in a significant impairment to the patient in day-to-day activities, that is: Australian Dental Journal 1996;41:1.

Table 1. Surgical procedures for temporomandibular disorders 1. Arthrocentesis and lavage 2. Arthroscopy 3. Arthrotomy (open joint surgery) 4. Modified condylotomy

a) Pain which is localized to the TMJ. b) Pain on loading of the TMJ. c) Pain on movement in the TMJ. d) Mechanical interferences in the TMJ. Table 1 lists the TMJ surgical procedures that are presently used for the treatment of TMD, and will be discussed briefly as follows.

Arthrocentesis and lavage TMJ arthrocentesis and lavage with manipulation is the simplest and least invasive of all surgical techniques. It was developed at the College of Dentistry, University of Florida, and subsequently published in the North American literature by Nitzan et aL6 Since then, it has become a useful method for the treatment of severe and persistent limited mouth opening of acute onset, resulting from closed locking of the TMJ. The concept was based on the observations that simple lysis and lavage of the upper joint space using arthroscopy was highly successful in re-establishing the normal range of mouth opening in patients with closed locking of their TMJs.’ It has been proposed that the success of this technique has cast doubt on an abnormal disc shape or position as being the cause of closed lock of the TMJ. Instead, it is speculated that the restricted gliding movement of the mandibular condyle over the articular eminence may be due to a reversible adhesion of the disc to the glenoid fossa caused by a vacuum effect or alteration in synovial fluid consistency.* The technique involves the insertion of two 20gauge needles into the superior joint space of the TMJ under local anaesthesia. Through one needle, 50 to 100 mL of Ringer’s lactate solution is injected into the superior joint space with the second needle acting as an outlet valve, effectively allowing lavage of the joint cavity. Lysis of adhesions is achieved by intermittent distension of the joint space by momentarily blocking the outflow needle and injecting under pressure during the lavage. Occasionally, steroids are injected at the end of the lavage to alleviate any intracapsular inflammation. Immediarely on completion and after the removal of the needles, the patient’s mandible is gently manipulated to help further free up the disc. The advantages of TMJ arthrocentesis and lavage are that it is a simple, inexpensive, and minimally invasive procedure with little morbidity that can be easily undertaken in an outpatient setting. It is most important to note, however, that this technique 17

Table 2. Advantages of arthroscopy versus arthrotomy

Table 3. Limitations of arthroscopy versus arthrotomy

1 . Less invasive 2. Less surgical trauma to joint 3 . More rapid recovery and shorter healing time 4. Inspection of joint structures in a surgically undisturbed joint 5. Ability to study in more detail certain areas of the joint 6 . Ability to witness function of a surgically undisturbed joint - Bronstein (1987)$

1 . Procedures confined to upper joint space 2. Only a limited range of operative procedures possible 3 . Cannot be used for the treatment of advanced joint pathosis 4. Expensive equipment with high maintenance costs

SBronstein SL. Proc 2nd Annual International Symposium on Temporomandibular Joint Arthroscopy. New York, 1987.

appears to be effective only for specific conditions, so appropriate case selection is mandatory for a successful outcome.6 Arthroscopy Arthroscopy of the TMJ developed as a spin-off from the technological advances made by orthopaedic surgeons in arthroscopy of the larger joints. The ability to miniaturize the arthroscopic telescope made it possible for Japanese workers to apply this technology to the relatively small dimensions of the TMJ, and the technique of TMJ arthroscopy was first introduced in the literature in 1975.9 It was not until almost a decade later that the concept of TMJ arthroscopy spread to Europe and the United States, as intense interest developed in the idea that an extended therapeutic application of arthroscopy could be established in addition to its diagnostic capabilities.'"-'* Arthroscopy is very much an equipment-dependent procedure which relies considerably on expensive and complex technology. Despite the minimally invasive nature of arthroscopy it is, nevertheless, performed under general anaesthesia in sterile conditions in the operating theatre, similar to an open surgical procedure. It takes a fair degree of skill and ability to conceptualize a three-dimensional space on a two-dimensional screen image, as well as a high degree of manual dexterity, particularly for operative procedures. The advantaged and limitations of arthroscopy compared with open joint surgery are listed in Tables 2 and 3. TMJ arthroscopy now plays as much a role in the management of certain TMDs as does open TMJ surgery. In fact, steady growth in the popularity of TMJ arthroscopy in recent years has led to the development of numerous sophisticated operative techniques ranging from simple lavage and ablation of adhesions to electrocautery and plication to reduce hypermobile joints." The complexity of the procedures that can be undertaken by an experienced arthroscopist are little short of incredible. However, despite the obvious advantage of reduced patient morbidity, arthroscopy is presently limited to the diagnosis and treatment of microscopic conditions confined to the upper joint space, although arthroscopists claim they can also successfully reposition displaced discs with this technique. l 4 18

Open TMJ surgery (arthrotomy) Arthrotomy refers to open surgical procedures of the joint itself. Although numerous surgical approaches to the TMJ have been described, the most common approach is via a preauricular incision made in the skin fold immediately in front of the ear. A more cosmetic endaural approach incorporating the tragus of the ear is often used where the local anatomy of the area is favourable to this approach. Upon exposure of the joint capsule, the superior joint space is entered first, but on some occasions the inferior joint space may require surgical e x p o s ~ r e . ~ Arthrotomy enables the surgeon to directly examine the intracapsular contents of the TMJ, as well as enabling many surgical procedures to be performed. Whilst other surgical procedures provide a limited range of options, arthrotomy provides the surgeon with an unlimited scope of procedures ranging from simple lavage and debridement of the joint to the complete removal of the d i s ~ . ~The , ' ~most commonly performed arthrotomy involves disc plication, that is, the repositioning and stabilization of a displaced disc with sutures that may or may not involve the removal of some excess or diseased disc tissue. Arthroplasty in the form of bone recontouring of the glenoid fossa, articular eminence or condylar head is sometimes necessary, particularly in cases of gross mechanical joint interference and advanced degenerative joint disease. Immediately after the surgery, the patient may experience swelling in front of the ear and a slight change in occlusion and limited mouth opening which usually resolves in about two weeks. All patients experience some numbness over the temple and part of the ear which usually resolves in about six weeks or more. The ear may feel congested postoperatively and in some cases the patient may experience dizziness which also resolves in one to two weeks. Despite the complexity of the surgery, hospitalization time is only two or three days with a postoperative recovery period of about two weeks with mild to moderate discomfort commonly experienced by the patient. During the postoperative period, adjunctive non-surgical therapies such as occlusal appliances and physiotherapy are continued. In this institution (the University of Florida) about 90 per cent of patients report an improvement in symptoms from open surgical procedures on the TMJ, and although ten per cent report no improvement after surgery, it is rare to see patients who feel Australian Dental Journal 1996;41:1.

they have become worse after surgery. Approximately 2.5 per cent of patients end up having a second operation. Complications are uncommon, with persistent malocclusion and persistent limited mouth opening occurring in less than 1 per cent of patients, especially in those who had undergone removal of the disc. Infection and paresis of the frontal branch of the facial nerve are equally uncommon in experienced hands.16

Modified condylotomy The modified condylotomy is basically a modification of the intraoral vertical ramus osteotomy used in orthognathic surgery to correct mandibular prognathism. The idea of osteotomizing the condylar process for the treatment of T M D was derived from observations that patients who had sustained condylar fractures rarely complained of TMD." In 1983, Nickersonl' developed the modified condylotomy procedure as a means of treating painful TMJ where there is evidence of a reducing displacement of the disc. Unlike TMJ arthrotomy which often aims to reposition a displaced disc, the aim of this procedure is to surgically reposition the condyle anteriorly and inferiorly beneath the displaced disc, effectively by increasing the joint space between the condyle and the fossa and hence allowing the disc to move posterosuperiorly and establish a more favourable condylardisc-fossa relationship. A recent study by Hall et al." conducted on 400 patients over a nine-year period found good pain relief in about 90 per cent of the patients treated with modified condylotomies. Although the surgery itself is simple enough, there is a prolonged period of postoperative rehabilitation involving three to six weeks of maxillo-mandibular fixation (MMF) with a further period of training elastics so that the occlusion is maintained in spite of the condylar sag which occurs with this procedure. Since this procedure does not directly involve the TMJ, intracapsular pathosis is not addressed, although it does appear that relief of symptoms may be due to decreased loading of the TMJ during the postsurgical MMF period with subsequent rehabilitation to the new condylar position. Orthognathic surgery Frequently a clinician may be confronted with the dual problem of a dentofacial deformity co-existing with a T M D in the same individual. The literature, however, has failed to identify a cause-and-effect relationship between T M D and dentofacial deformities, but rather suggests that the malocclusion (in conjunction with the dentofacial deformity) may be considered as an exacerbating factor rather than an aetiological factor in patients who are predisposed to TMD.2n When faced with the prospect of treating a patient with a dentofacial deformity and concomitant Australian Dental Journal 1996;41:1.

TMD, it is essential to develop a treatment strategy that will address both problems. The priority, however, must be directed towards treating the condition with the most severe symptoms first. Hence pain arising from the T M D must be settled initially, prior to the treatment of the malocclusion. Therefore, before undertaking orthognathic surgery the symptoms of TMD, such as pain and muscle spasm, must be controlled first through non-surgical means. The non-surgical treatment of the T M D must continue right throughout the orthodontic phase as well as pre- and post-orthognathic surgery.*O Where mandibular ramus osteotomies are planned, particularly for setback procedures, then vertical ramus osteotomies with a period of postoperative intermaxillary fixation is recommended for the same reasons as condylotomies are used for the treatment of T M D as discussed previo~sly.'~ White and Dolwickzl undertook a retrospective study of 75 patients who had undergone orthognathic surgery, half of whom had features diagnostic of T M D preoperatively. After orthognathic surgery, 89.1 per cent of symptomatic patients experienced improvement of their TMD, 2.7 per cent remained unchanged, and 8.1 per cent got worse. It is impossible, however, to predict whether orthognathic surgery will lead to the resolution of T M D in any individual case, but in view of the results of this study it is highly recommended that orthognathic surgery be undertaken well before any TMJ surgery is contemplated. Furthermore, simultaneous orthognathic and TMJ surgery should be avoided because joint swelling as a result of surgery will make control of the occlusion quite difficult, and prolonged intermaxillary fixation, if required for an orthognathic procedure, may be deleterious to an operated TMJ.Z" Afcer the completion of orthodontics and orthognathic surgery, the status of the T M D is re-evaluated, and if symptoms remain severe and refractory to further non-surgical therapy, TMJ surgery may be considered.

Conclusions Surgery of the TMJ is best undertaken by surgeons who maintain the philosophy that surgery should aim to avoid further harm to the joint itself and err on the side of more conservative surgical procedures. The benefits and limitations of each of the surgical procedures are readily determined on an individual case basis. The goal is to determine the most appropriate technique that will yield the highest probability of success with the lowest morbidity. It is important for all clinicians involved in the management of T M D to be aware of the current surgical options available, especially for patients who fail to respond to conventional non-surgical treatment over a considerable period of time. Dentists should acquaint themselves with the benefits derived 19

from surgery and always keep in mind that a team approach to the management of T M D and careful case selection, particularly where surgery is planned, are the most important ingredients for an overall successful outcome.

References 1. McNeill C, ed. Temporomandibular disorders. Guidelines for classification, assessment and management. 2nd edn. Chicago: Quintessence, 1993.

2. Wilks CH. Internal derangements of the temporomandibular joint. Arch Otolaryngol Head Neck Surg 1989;115:469-75. 3. Howerton DW, Zysset M. Anatomy of the temporomandibular joint and related structures with surgical anatomic considerations. Oral Maxillofac Surg Clin North Am 1989;1:229-48. 4. Dolwick M E Clinical diagnosis of temporomandibular joint internal derangement and myofascial pain and dysfunction. Oral Maxillofac Surg Clin North Am 1989;l:l-6. 5 . Dolwick MF, Sanders B. TMJ internal derangement and

arthrosis. Surgical atlas. St Louis: CV Mosby, 1985. 6. Nitzan DW, Dolwick MF, Martinez GA. Temporomandibular joint arthrocentesis: A simplified treatment for severe, limited mouth opening. J Oral Maxillofac Surg 1991;49:1163-7. 7. Nitzan DW, Dolwick M E Arthroscopic lavage and lysis of the temporomandibular joint: A change in perspective. J Oral Maxillofac Surg 1990;48:798-801.

8. Nitzan DW, Dolwick MF. An alternative explanation for the genesis of closed-lock symptoms in the internal derangement process. J Oral Maxillofac Surg 1991;49:810-5.

12. Bronstein SL. Diagnostic and operative arthroscopy: Historical perspectives and indications. Oral Maxillofac Surg Clin North Am 1989;1:59-68. 13. McCain JP, Humberto R. Principles and practice of operative arthroscopy of the human temporomandibular joint. Oral Maxillofac Surg Clin North Am 1989;1:135-52. 14. McCain JP, Podrasky AE, Zabiegalski NA. Arthroscopic disc repositioning and suturing: A preliminary report. J Oral Maxillofac Surg 1992;50:568-73. 15. Piper MA. Microscopic disc preservation surgery of the temporomandibular joint. Oral Maxillofac Surg Clin North Am 1989;1:279-302. 16. Dolwick MF, Nitzan DW. TMJ disk surgery: 8-year follow-up evaluation. Fortschr Kiefer Gesichtschir 1990;35:162-7. 17. Ward TG. Surgery of the mandibular joints. Ann R Coll Surg Eng 196 1;28:139-45. 18. Hall HD, Nickerson JW, McKenna SJ. Modified condylotomy for treatment of the painful temporomandibular joint with a reducing disc. J Oral Maxillofac Surg 199331:133-42. 19. Upton LG, Sullivan SM. Modified condylotomies for management of mandibular prognathism and TMJ internal derangement. J Clin Orthod 1990;24:697-703. 20. Ochs MW, LeBanc JP, Dolwick M E The diagnosis and management of concomitant dentofacial deformity and temporomandibular disorder. Oral Maxillofac Surg Clin North Am 1990;2:669-90. 21. White CW, Dolwick M E Prevalence and variance of temporomandibular dysfunction in orthognathic surgery patients. J Adult Orthod Orthognath Surg 1992;7:7-13.

9. Ohnishi M. Arthroscopy of the temporomandibular joint. uapanese text.) J Jpn Stomat 1975;42:207-12. 10. McCain JP.Arthroscopy of the human temporomandibular joint. J Oral Maxillofac Surg 1988;46:648-52. 11. Sanders B. Arthroscopic surgery of the temporomandibular joint: Treatment of internal derangement with persistent closed lock. Oral Surg Oral Med Oral Pathol 1986;62:361-4.

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Address for correspondencelreprints: Dr George Dimitroulis, 5 Oban Street, South Yarra, Victoria 3 14 1.

Australian Dental Journal 1996;41:1.

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