The initial diagnosis and treatment of facial pain and temporomandibular disorders (TMD) is becoming a routine part of practice for many general dentists. Some studies estimate the prevalence of clinically significant TMD to be as high as five percent of the general population with as many as two percent seeking some form of treatment for it (Dekanter 1992, Sep; Goulet 1995, Nov). Clinical experience and published literature suggests that conservative, non-surgical interventions, may account for as high as a 74 to 85 percent positive response rate in symptomatic TMD patients (Okeson 1986, Apr; Greene 1988, Sep). Likewise, other sources have even suggested that almost all patients with TMD will improve with time, regardless of the type of treatment they receive (Green 1982, Aug; Mejersjo 1983, Jun; Greene 1988, Sep; Nickerson 1989; Okeson 1989; McNeill 1993). Consequently, very few individuals with this disorder will ever require surgical intervention. The intent of this article is to provide the dental community with an overview of surgical treatment options that are available for those rare patients in whom conservative therapy has failed and surgery is indicated.
TMD is the general term used to describe pain and/or dysfunction of the masticatory apparatus including the temporomandibular joint, masticatory muscles, and supporting structures (Okeson 1997, Jan). Disorders of the Temporomandibular joints are one subset of TMD. For the purpose of this article, Temporomandibular Joint Dysfunction/ Disorders will be referred to as TMJD. The etiology of TMJD is multifactorial and signs and symptoms may be quite variable. Those presenting for treatment are more likely to be female (deBont 1997, Jan; Carlsson 1999, Fall). TMJD may be classified as articular (within the joint) or non-articular (outside the joint).
Non-articular disorders commonly present as masticatory muscle dysfunction associated with poorly localized pain and a symmetrically reduced range of mandibular motion. Synonyms for this condition include myofascial pain dysfunction syndrome (MPD), TMJ dysfunction syndrome, craniomandibular dysfunction and facial arthromyalgia. Non-articular TMJD is a more common entity than are the articular TMJD counterparts (Al-Ani 2004). Response to conservative, reversible, non-interventional therapy is usually good. Conversely, surgical intervention is of no value in musculo-ligamentous disorders.
Articular TMJD may present with signs and symptoms quite similar to the more common non-articular TMJD. As a result, an accurate diagnosis can be more difficult for the inexperienced clinician. However, more localized pre-auricular pain and the likelihood of asymmetric mandibular function such as ipsilateral deviation on opening and restricted lateral excursions to the contralateral side suggest an articular disorder. Articular TMJD may be further sub-classified into non-inflammatory, inflammatory, neoplastic, and internal derangement. The term “internal derangement” is used to describe alterations in disc-fossa relations (Wilkes 1978, Sep-Oct). Internal derangements may be associated with any of the articular etiologies.
Primary goals in treatment of TMJD are to alleviate pain and to improve mandibular biomechanical function. The importance of initial conservative approaches in the management of TMJD cannot be overstated for reasons that are not yet fully understood. These treatment modalities, when adhered to for two to three months (either alone or in combination), often provide the majority of patients with relief and/or resolution of signs and symptoms. Contemporary conservative TMJD management may include any or all of the following: Diet modification, pharmacotherapy (analgesics, non steroidal anti-inflammatories, anxiolytics, antidepressants, muscle relaxants, local anesthetics), physical therapy (exercise, thermal agents, ultrasound, electrical stimulation, iontophoresis, trigger point muscle injections), stress reduction techniques (relaxation and biofeedback; psychotherapy) alternative therapy (acupressure and acupuncture; chiropractic), and occlusal splint therapy. (Al-Ani 2004; Forssell 2004, Winter). It is to be understood, however, that “because conservative therapy has failed to offer relief of signs and symptoms of TMJD, it does not necessarily follow that surgery will do so.”
Surgical intervention is appropriate only when:
1) There is identifiable pathology amenable to surgical intervention.
2) There is resultant loss of mechanical function
3) There is pain related to joint pathology
4) Any of the above has failed to respond to non-interventional treatment and there is, as a result, persistent loss of enjoyment of normal mandibular function which is negatively affecting the patient’s well being in a persistent and unremitting manner.
5) There has been a thorough explanation of the relative pros and cons of a specific intervention, a review of the potential benefits, risks and complications.
A surgical assessment (work-up) will include:
1) A complete review of the nature of the TMJD and all treatment attempts to date
2) Radiographic assessment including any or all of the following: dental panoramic radiograph, CT scan, MRI, bone scan.
3) A thorough medical assessment to include medical risk factors that may affect the surgical outcome.
The following TMJ Articular Disorders are manageable with surgical intervention:
1) Internal Derangements (disc displacement disorders)
2) Non-Inflammatory (non-infective degenerative disorders; post traumatic degeneration)
3) Inflammatory Disease (osteomyelitis, synovitis, Lupus, psoriasis, Rheumatoid Arthritis)
The following is a review of the surgical procedures that can be employed in the management of TMJD.
ARTHROCENTESIS & ARTHROSCOPY
TMJ arthrocentesis and arthroscopy are minimally invasive surgical techniques used in the management of TMJD.
Arthrocentesis is an office-based procedure that involves the placement of two needles into the superior joint space for the purpose of hydraulic distension then joint lavage. (Figs. 1-3) In the acute “closed lock” or in the painful self-reducing disc displacement disorder (Emshoff 2004, Jul), arthrocentesis will help mobilize an entrapped disc and will remove nociceptive inflammatory mediators. While studies have shown it to be more efficacious in the treatment of patients with acute/non-chronic pain (Emshoff 2004, Jul), some authors believe it should be attempted before performing any open surgical procedure (Heffez 2004). The technique itself involves the continual flushing of the superior joint space with a minimum of 100 cc. of lactated Ringer’s or normal saline solution (Kaneyama 2004, Jun).
Arthroscopic surgery is considered a minimally invasive diagnostic and therapeutic procedure however it is usually done in the hospital out-patient setting. Most arthroscopic procedures are used for diagnosis, lysis of adhesions and lavage of inflammatory mediators within the superior joint space. A thin fiberoptic device (typically 2.7mm diameter), attached to a high intensity light source and camera is inserted through a 3mm cannula into the superior joint space (Fig. 4). This technique allows a direct view displayed on a video monitor, of all tissues in the joint space (Figs. 5 & 6). Therefore, an accurate diagnosis can be made by virtue of directly visualizing the pathology. With the insertion of a second cannula and with special surgical instruments, certain surgical procedures may be undertaken under direct arthroscopic visualization. In skilled hands, disc plication and the removal of degenerative fibrocartilage and intra-joint adhesions can be done. Treatment goals include a reduction in pain and improved bio-mechanical function, as well as the formulation of an accurate diagnosis (Goss 1987, Apr; Holmund 1988, Feb).
The first reports of TMJ Arthroscopy were published in 1975 (Ohnishi 1975).
Since that time, advances in both technology and technique have paved the way for a procedure that has demonstrated favourable results with low morbidity rates (McCain 1992, Sep). Indications for arthroscopic surgery include:
1) TMJ pain and/or dysfunction
2) hypomobility (unilateral or bilateral) associated with internal derangements characterized by both self reducing or non-self reducing disc displacement
3) synovitis; fibrous adhesions;
5) minor osteoarthritis (Goss 1987, Apr; Sanders 1987, Fall)
TMJ arthroscopy is contraindicated in patients who have infection in the TM Joint and/or the overlying tissues and in those with bony ankylosis. While minimally invasive, there is the potential for complications from the procedure itself and while they are uncommon, informed consent is required.
Condylotomy is an osteotomy (a controlled fracture) performed through the condylar neck/vertical mandibular ramus. It is indicated for internal derangement, specifically and most predictably in the management of recurrent self-reducing disc displacement. It may be used in non-self reducing disc displacement and has been reportedly helpful in recurrent dislocation. It is theorized that the osteotomy allows antero-medial repositioning of the condyle by virtue of contraction of the lateral pterygoid muscle, which, in turn, fosters a “new equilibrium” of the condyle-disc relationship. Additionally, it may produce “condylar sag” which increases the joint space, thereby allowing for passive repositioning of the disc. The principle goal of this procedure is to allow pain free and unrestricted mandibular range of motion.
This procedure has evolved since it was first described by Kostecka (Maccaferri 1951, Apr) in the 1950’s, from an extra-oral “blind” procedure performed using a “Gigli saw”, to one that is routinely performed in the hospital setting via a modified intra-oral vertical ramus (IVRO) approach (Hall 1996 Sep.). In this technique, the lateral aspect of the ramus is exposed from the angle to the sigmoid notch through an intraoral incision with subsequent subperiosteal dissection and detachment of the masseter muscle. Next, an oscillating saw is used to complete a vertically oriented osteotomy extending from the sigmoid notch down through the inferior border of the mandible approximately 6-8 mm anterior to the posterior border behind the neurovascular bundle. Upon completion of the osteotomy, the patient is placed in maxillo-mandibular fixation (MMF) and the bony segments are then addressed to ensure that the proximal condylar segment is laterally buttressed up against the distal tooth-bearing segment (Figs. 7-9). Postoperatively, most clinicians observe a two-week period of MMF, followed by the use of training elastics for an additional three to four weeks. This procedure, when indicated, has proven itself to be an effective operation for managing pain and diminished function of temporomandibular joints in both the reducing disc and non-reducing disc displacement scenarios, with favorable outcomes being cited in over 94 percent and 87 percent of patients, respectively (Hall 2000 Jan; Hall 2000, Feb).
Arthroplasty is an umbrella term that refers to a group of TMJ surgical procedures approached with an incision directly into the joint itself. They are indicated for those patients with progressively debilitating internal derangement refractory to the non-surgical and minimally invasive techniques described above. Other indications include severe degenerative joint disease, the treatment of various pathologic processes and ankylosis. The most widely used incision of the many possible approaches to the TMJ is the classic pre-auricular approach.
The modern pre-auricular approach has evolved from one which was first described and used in 1913 for the treatment of TMJ ankylosis (Blair 1928). Using this approach, access to the TMJ is accomplished via a curvilinear incision extending from the temporal hairline inferiorly within a pre-auricular skin crease to a level superior to the lobule of the ear (Fig. 10). The location of this incision and surgical dissection is limited by the position of the underlying neurovasculature. Specifically, the position of the temporal branches and the main trunk of the facial nerve, which have been well described in the literature, course through the tissues adjacent to the TMJ, and must be avoided (Al-Kayat 1979). Through this approach, most TMJ surgical procedures can be performed.
The majority of arthroplasty procedures performed are aimed at the treatment of damaged, diseased or malpositioned discs. Specifically, disc plication is advocated for restoring the normal condyle-disc relationship when an otherwise healthy disc is displaced antero-medially. In these scenarios, the displaced disc is repositioned postero-laterally by a combination of retro-discal tissue reduction and re-attachement, often combined with an anterior band release. The disc is then sutured to the lateral TMJ capsule. When a disc is damaged beyond repair, disc removal also known as a discectomy/menisectomy is indicated. When a discectomy is performed, decisions regarding management of the condylar hard tissues, as well as disc replacement must be made. With respect to the condition of the condyle, severe disc pathology is often associated with significant underlying hard tissue changes that must be addressed either through a partial (high condylar shave) or total (gap arthroplasty) condylectomy (Fig. 11). This simultaneously serves to increase the joint space and remove the underlying osseous pathology. Regarding the re-establishment of a soft tissue interface between the glenoid fossa and the condyle; a number of surgical options exist. These include autogenous regional or free-tissue grafts (temporalis muscle, dermis, cartilage, or fat), or alloplastic materials (Fig. 12). Each is intended to fill in the resultant dead space in order to prevent bone-to-bone contact, and minimize the potential for the development of TMJ ankylosis.
PROCEDURES FOR HYPERMOBILITY
Hypermobile Temporomandibular joints are those joints that are prone to frequent and recurrent subluxation or dislocation. In either scenario, hypermobility actually refers to a situation in which the mandibular condyle translates beyond its normal range with respect to the articular eminence. The possible etiologies of TMJ hypermobility include: overextension injuries, trauma, connective tissue disorders that result in laxity of the TMJ capsule and ligaments, internal derangement and degenerative joint disease (Rotskoff 1992).
Subluxation refers to an incomplete dislocation of the mandibular condyle, whereby the condyle translates beyond the articular eminence on opening, but either spontaneously returns to or can be manipulated back into the glenoid fossa by the patient. Complete dislocation represents the most extreme scenario with respect to a hypermobile TMJ. It occurs when the mandibular condyle moves into a position anterior to the articular eminence resulting in mandibular “open-lock”. In this case, the mandibular condyle cannot be self-reduced and usually requires immediate attention (Figs. 13 & 14).
Most severe TMJ hypermobility conditions can effectively be managed by manual reduction followed by a period of complete rest for at least two weeks. After the initial episode, patients are educated about hypermobility and are strongly advised to avoid any potential triggers. Surgical management of TMJ hypermobility is reserved for either acute TMJ dislocations that cannot be manually reduced, chronic dislocation where the mandibular condyle has been dislocated for an extended period of time, or a pattern of recurrent dislocation that is occurring with increasing frequency and is adversely effecting one’s quality of life (Caminiti 1998, Jul-Aug).
Surgical procedures for the treatment of chronic or recurrent TMJ dislocation can be divided into two subgroups; those that limit the range of c
ondylar movement, and those that remove the blocking factor that prevents the condyle from returning to its normal position within the glenoid fossa upon mandibular closing. The “eminectomy” was the first technique used to eliminate the blocking factor preventing the mandibular condyle from returning to its rest position within the glenoid fossa (Myrhaug 1951, Sep). This procedure is performed through a standard pre-auricular approach. Following exposure of the articular eminence, it is osteotomized and removed, leaving a flat smooth surface anterior to the glenoid fossa over which the mandibular condyle can slide with out any interference.
Surgical procedures that limit the translatory path of the mandibular condyle were first described by Mayer in 1933, who advocated the surgical displacement of a portion of the zygomatic arch inferiorly to block excessive translation of the TMJ condyle (Mayer 1933). LeClerc and Girard improved on this technique when they described a method whereby a thicker portion of the zygomatic arch is osteotomized and downfractured, in order to block excessive translation of the mandibular condyle (Leclerc 1943).
Other surgical procedures used to treat chronic TMJ dislocation include capsular plication to tighten the TMJ capsule and limit translatory movement of the mandibular condyle, lateral pterygoid myotomies, condylotomy. Some of these may be performed by using advanced arthroscopic surgery. The injection of a sclerosing solution into the TMJ ligaments in order to induce scar formation may limit the movement of the mandibular condyle (Rotskoff 1992).
TOTAL JOINT RECONSTRUCTION
Total TMJ reconstruction is defined as the replacement of the articulating surfaces of both the glenoid fossa and mandibular condyle (Spagnoli 1994; Braun 2002). While many autogenous and alloplastic options for total TMJ reconstruction are viable (Fig. 15), we favor the use of an ultra-high molecular weight polyethylene fossa designed to function against a condylar component consisting of a highly polished Cobalt-chromium-molybdenum alloy with titanium alloy coating (Figs. 16 & 17).
Alloplastic TMJ reconstruction is a biomechanical as opposed to a biological solution to advanced anatomic TMJ pathology. The indications for alloplastic TMJ reconstruction include: 1) ankylosed, degenerated or resorbed joints with severe anatomic abnormalities (Fig. 18), 2) failure of autogenous grafts in the multiply operated patient (Fig. 19), and 3) severe inflammatory joint disease such as rheumatoid arthritis, 4) failed previous alloplastic reconstruction, 5) recurrent ankylosis associated with excessive heterotopic bone formation (Quinn 2002, Sep). This center has had extensive experience with this procedure since 1995. To date, 213 patients have received 374 total joint replacements.
With respect to total TMJ reconstruction, success is measured in terms of restoration of TMJ function. In our experience, careful patient selection has resulted in a substantial improvement in quality of life for a majority of our patients. However, due to the complex nature of TMJ function, it is extremely difficult to reconstruct any joint back to its normal pre-morbid function. Pain relief gained is often a secondary benefit, and quite often these patients require co-management with a chronic pain service. It must be stressed that total TMJ reconstruction, with some specific exceptions such as in patients with severe rheumatoid TM Joint degeneration, is an end-stage procedure, and that the need for reconstruction indicates severe pathology not amenable to any other treatment modality.
TMD is widespread in the population and is often associated with pain and dysfunction of the TMJ. The general dentist is often in a position to offer initial diagnosis and conservative management in the early phase of the disorder. Most patients will respond positively to conservative management. However, for those patients whose conditions are refractory, or if other pathology is identified, TMJ surgery may be appropriate. Regardless of the surgical procedure that is performed, aggressive, immediate, post-operative patient directed physiotherapy is the key to a successful outcome (Fig. 20). Early mandibular mobilization is of paramount importance with respect to the prevention of scar formation, pain and hypomobility. Long-term follow-up is required.
Dr. McGuire is Chief Resident of the graduate residency training program in Oral and Maxillofacial Surgery & Anesthesia, Faculty of Dentistry, University of Toronto. Clinical activities are based primarily at the Mount Sinai Hospital and are affiliated with the Hospital for Sick Children, Sunnybrook and Women’s College Health Sciences Centre and the Bloorview MacMillan Children’s Centre.
Dr. Rittenberg is an attending staff Oral and Maxillofacial Surgeon at Mount Sinai Hospital in Toronto. He also maintains a private practice in Oral and Maxillofacial Surgery in Toronto and Richmond Hill, ON.
Dr. Baker is an Assistant Professor, Faculty of Dentistry, and is Head, Division of Oral & Maxillofacial Surgery, Mount Sinai Hospital and Director of its Regional Treatment Centre for Temporomandibular Joint Reconstruction.
Acknowledgment is given to Dr. David Psutka, senior surgeon in the Mount Sinai Hospital’s Centre for Temporomandibular Joint Reconstruction for both his surgical expertise and for use of some clinical photographs from his teaching collection.
Oral Health welcomes this original article.
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