Surgery has often been called “the cry of defeat.” When all else fails, removal or rearrangement of the parts offers a last opportunity to resolve the problem. However, until such time as there is a better understanding of the etiology of the various disease processes that affect the human body, and medical interventions can be used to prevent or treat these conditions, surgery still represents a viable alternative. This is true in the temporomandibular joint (TMJ) as well as in other regions of the body. A review of the literature, however, indicates that surgery of the temporomandibular joint for the management of conditions causing chronic pain has a history of varied and unpredictable results. Because such forms of surgery are commonly used, it is important to understand the reasons for this unreliability so that efforts can be made to improve the utility of these procedures.
The most common reason for unsuccessful TMJ surgery is a failure to eliminate the underlying cause of the problem in addition to the obvious pathology. Too often, the surgeon deals only with the immediate situation and fails to consider what initially led to its development. Unless the latter is done, there is a great risk of the same factors leading to a recurrence of the condition.
Another common reason why TMJ surgery may be unsuccessful is the establishment of a wrong preoperative diagnosis. Because of the similarity in signs and symptoms between patients with masticatory muscle pain and dysfunction (MPD) and those with certain diseases of the TMJ, as well as because of the frequent etiologic interrelationship between muscle and joint problems, TMJ surgery is often done for persons with primarily a myofascial pain problem. On the other hand, a correct diagnosis can be made, but the patient may be inappropriately treated with surgery when medical management is actually indicated. Moreover, even when surgery is indicated, and the appropriate operation is done, insufficient attention to proper postoperative care and rehabilitation can still lead to a less than satisfactory outcome.
When all of the factors that can contribute to the varied and unpredictable results with TMJ surgery are considered, two things become apparent: first, that improper diagnosis is a key factor, and second, that when surgery is used, it is essential to understand which conditions are amenable to operation, when it should be done, and what can be accomplished.
There are many pathologic conditions involving the temporomandibular joint. These include congenital and developmental anomalies, traumatic injuries, various forms of arthritis, neoplastic disease, and internal derangements. However, only the arthritides and the internal derangements commonly give rise to chronic TMJ pain.
The TMJ is subject to all of the forms of arthritis that affect other joints in the body. Thus, in addition to the commonly encountered cases of rheumatoid and degenerative arthritis, one may see patients with rheumatoid variants (psoriatic arthritis and ankylosing spondylitis), infectious arthritis, posttraumatic arthritis, and metabolic arthritis (gout and pseudogout). Because the latter conditions are relatively uncommon, and also because their treatment is usually medical rather than surgical, only the treatment of rheumatoid and degenerative arthritis is considered here.
The primary management of rheumatoid arthritis of the TMJ is medically based, and surgery, therefore, plays a role only in the treatment of such structural sequelae as ankylosis, apertognathia or facial deformity. These conditions, however, are generally not associated with chronic pain and are treated mainly for functional or esthetic reasons. Although synovectomy has been used to treat rheumatoid arthritis in other joints, it has rarely been attempted in the TMJ. This is because the complex anatomy makes complete removal of the pathololgic tissue extremely difficult. However, when surgery has been used in the former instances, it has been shown that removal of the diseased synovial tissues results in the regeneration of a new synovial membrane that is surprisingly resistant to the redevelopment of inflammation.
Osteoarthritis is associated with both degenerative change and chronic pain. As in other parts of the body, the pain is usually managed medically by reduction of physical load on the joint and the use of nonsteroidal anti-inflammatory drugs. There are some patients, however, in whom the condition does not respond to such therapy, and surgery has been recommended. The rationale for such procedures appears to be the restoration of smooth articulating surfaces and/or the reduction of intra-articular load.
A variety of operations have been suggested to achieve these objectives, including condylotomy, condylectomy, high condylectomy (condylar shave) with and without replacement, and arthroplasty. Although one can find anecdotal reports of success with all of these procedures, there have been no randomized clinical trials to evaluate the true results of such operations. Even the retrospective reports are difficult to interpret because the criteria for case selection are generally unclear, and it is often not possible to determine the precise condition for which the procedure was done. Although high condylectomy has been the most popular operation, clinical observations have shown that removal of the entire cortical covering of the articular surface of the condyle seems to lead to a continuation of the pain and the degenerative process in some patients. Therefore, arthroplasty, with removal of only areas of osteophyte formation and smoothing of areas of erosion, is a more logical procedure. A prospective comparison between high condylectomy and arthroplasty, however, has not been done, and there appears to be no scientific reason for the current manner in which operative procedures are selected.
Although limitation of mandibular movement is a frequent reason for surgical treatment of the nonreducing anteriorly displaced disc, persistent pain is also a major factor in many cases. Such pain, just as in patients with anteriorly displaced reducing discs, is caused by compression of the retrodiscal tissue, synovitis, and accompanying degenerative joint disease. However, because of the chronicity of these conditions, the pain is usually more severe.
Arthrotomy is frequently used to treat painful limitation of mouth opening associated with disc displacement or adhesion. Most surgeons attempt to reestablish disc mobility and reposition the disc in its normal anatomic position (discoplasty). However, when there is irreparable perforation of the disc, or the disc is so misshaped, shortened, or rigid that it cannot be properly repositioned, removal (discectomy) is indicated. There are also surgeons who believe that discectomy rather than discoplasty is indicated for all anteriorly displaced nonreducing discs.
Once the disc is removed, there is the question of whether replacement is necessary to prevent recurrent pain. Although the use of alloplastic interpositional materials such as Silastic or Proplast-Teflon was originally reported to be highly successful, subsequent studies showed that particulation of the implant under function produces a severe foreign body reaction associated with bone destruction and pain. As a result, these materials were withdrawn from the market.
Because of the problems with alloplastic interpositional materials, attention has been turned to the use of autogenous tissue following discectomy. Three main tissues have been used: temporalis muscle, auricular cartilage, and dermis. Anecdotal reports of experience with small numbers of cases in which these tissues have been used indicate that pain is reduced or eliminated. However, precisely how effective these tissues are, and whether one or another is preferable, still remains to be determined.
Because of failure with the use of alloplastic disc replacement, and the current lack of objective data to support the use of autogenous tissues, some surgeons have elected to perform discectomy without replacement. In the few retrospective studies reported in the literature, radiographic changes in condylar morphology, crepitus, and some pain have been a consistent finding. Such findings indicate the need for prospective studies comparing discectomy with and without replacement.
Arthroscopy also has been used to treat the painful anteriorly displaced disc as well as those patients in whom disc position is relatively normal but adhesion to the glenoid fossa results in limited mouth opening. Generally such treatment involves lysis, lavage, and debridement. Follow-up studies have shown that postoperatively patients show considerable reduction in pain and greatly improved range of jaw movement even though disc position is relatively unchanged. Such findings suggest that joint mobility rather than disc position is the important factor in the reduction of symptoms. On the basis of this concept, plus the fact that lysis and lavage appear to be the most effective component of the arthroscopic procedure, the use of TMJ arthrocentesis has been introduced. Although this procedure also has been used for treatment of rheumatoid and degenerative arthritis, its main use is in the treatment of patients with anteriorly displaced nonreducing discs or those in whom the disc is in relatively normal position but is adhered to the glenoid fossa. Arthrocentesis involves establishing inlet and outlet portals in the upper joint space with hypodermic needles, irrigation of the joint with lactated Ringer’s solution, and lysis of adhesions by hydraulic distention of the joint and manual manipulation. Steroid is also injected in some instances. The good results with this relatively risk-free procedure suggest that its use is preferable to arthroscopic or open surgery in the initial management of most patients with nonreducing or adherent discs.
Although surgery is frequently used to treat painful conditions involving the temporomandibular joint, a review of the literature provides little objective evidence regarding the efficacy of most of these procedures. Despite the fact that clinicians can point to cases treated successfully, and anecdotal reports, case studies, and retrospective analyses also show that persons with certain TMJ problems can be helped by surgery, the specific indications for such operations, and which operations are most efficacious, still remain to be determined. Without such information, some patients who do not require surgery may, on occasion, inadvertently receive it, and others who require surgery may not. To resolve these issues will necessitate the initiation of long-term, prospective, randomized clinical trials with specific inclusion and exclusion criteria, proper study design, use of uniform operative procedures, a clear definition of treatment goals and objective outcome criteria, and appropriate data analysis.
Despite the deficiencies of retrospective studies and case reports, they do provide evidence that surgery can be helpful for some patients suffering from painful disorders of the TMJ that do not respond favorably to nonsurgical management. Past experience, however, has shown that reliance solely on such data can lead to serious consequences. Until objective prospective data become available, therefore, clinicians need to adopt a conservative approach in their selection of patients for temporomandibular joint surgery and patients have to be wary about subjecting themselves to such procedures.
Written by Dr. Daniel Laskin