Abstract
Acute temporomandibular joint dislocation is a common occurrence that is generally treated by conservative therapy. In some patients, this can become a chronic recurrent condition. This recurrent temporomandibular joint dislocation (RTD) can significantly decrease the patient’s quality of life and require some form of surgical intervention for correction. The purpose of this study is to present a minimally invasive alternative treatment for RTD using operative arthroscopy. 11 patients treated for recurrent temporomandibular dislocation between 2004 and 2010 were retrospectively analyzed. Electrothermal capsulorrhaphy was performed using a standard double puncture operative arthroscopy with a Hol:YAG laser and/or electrocautery. Postoperatively the patients were monitored for 6 months to 6 years. Of the 11 subjects, 2 suffered a recurrence of temporomandibular dislocation and required open arthrotomy for correction. The other 9 patients had no signs of recurrence or any significant postoperative loss of function. Electrothermal capsulorrhaphy is an effective and minimally invasive method for the treatment of RTD.
Temporomandibular joint (TMJ) dislocation usually occurs as a singular episode which can be treated by conservative nonsurgical therapy and subsequently prevented by a period of immobilization and behaviour modification. Many central and neuromuscular etiologies can contribute to the progression from an acute situation into a recurrent one. Even in the absence of these etiologies, an improper period of immobilization can cause incomplete healing of stretched and torn ligaments and lead to an induced hypermobility and recurrent temporomandibular dislocation (RTD). RTD can be psychologically distressing for the patient who is constantly in fear of dislocation during jaw opening. It can also be costly and time consuming for the patient who frequently seeks medical attention for reduction.
Terminology used in the literature to describe RTD and associated conditions can be confusing and contradictory. TMJ dislocation has also been described as mandibular dislocation, condylar dislocation, and luxation. The incidence has been described as acute, chronic, recurrent, and long-standing. For the purposes of this study the term TMJ dislocation will be used to describe the situation where the mandibular condyle translates anterior to the peak of the articular eminence and does not reduce without assistance. TMJ dislocation was further described by Silver and Simon in 1961 as mensicotemoporal or meniscocondylar, the former describing the more common dislocation of the meniscocondylar unit dislocated in unison anterior to the articular eminence and the later describing the condyle dislocated anterior to the posteriorly displaced meniscus. Nitzan in 2002 also described this phenomenon as condylar dislocation (meniscotemporal) and ‘open lock’ (meniscocondylar). Subluxation, also described as partial dislocation, indicates the same relationship of the condyle and articular eminence but varies in that it is temporary and self reducing. TMJ hypermobility refers to an increased range of motion with the ability of the condyle to translate freely over the peak of the articular eminence and back into the fossa.
The typical clinical presentation of a patient with a TMJ dislocation includes an inability to close the mouth, protruding chin, preauricular pain, masticatory muscle tenderness, and difficulty with speech and controlling secretions. The hallmark of unilateral cases is deviation towards the unaffected side with lateral posterior crossbite. Plain film imaging such as lateral, oblique, transcranial, and panoramic views are sufficient for diagnosis. Magnetic resonance imaging (MRI) may be useful in the case of meniscocondylar dislocation, although this can often be diagnosed by the position of the condyle directly over the peak of the articular eminence as opposed to anterior to it. It is important to diagnose a meniscocondylar dislocation from a true TMJ dislocation as it can be treated with hydrodistension of the superior joint space by arthrocentesis or arthroscopy.
The prevalence of RTD has not been well studied in the literature. It is generally considered to be rare compared with other temporomandibular disorders. According to Boering’s study of 400 patients, 5 revealed a history of temporomandibular dislocation and 8 sought primary treatment for TMJ dislocation, 3.25% of his patient pool. A study by Luz and Oliveira showed TMJ dislocation to be the diagnosis in 22.5% of patients treated for temporomandibular disorders in the emergency room over a 6-year period. The reported incidence of TMJ hypermobility and subluxation in the general population is variable, 21–70%. Irrespective of the prevalence of RTD, it is a condition that can be attributed to multiple etiologies and may require surgical intervention for treatment.
The aetiology of TMJ dislocation can be traumatic, secondary to extreme or prolonged opening, ligament or capsular laxity, internal joint derangement, neuromuscular, or psychogenic. Traumatic aetiology can be in the form of direct trauma (assault, fall, sports injury) or indirect (whiplash). Dislocation has also been reported after prolonged opening (dental appointments) or extreme opening and yawning, intubation and bronchoscopy.
Ligament and capsular laxity can be caused by incomplete healing after a primary injury, familial connective tissue disorder, generalized joint hypermobility, from chronic over rotation in edentulous patients with decreased vertical dimension and degenerative joint disease. Internal joint derangement is the aetiology in the case of meniscocondylar dislocation and should be differentiated carefully. Psychogenic dislocation has been described as the aetiology in psychiatric patients who purposely dislocate. Neuromuscular etiologies have been reported secondary to tardive dyskinesias induced by extrapyramidal effects of prochlorperazine, metoclopromide, phenothiazine, haloperidol, and thiothixene. Other central etiologies creating extrapyramidal dysfunction include Parkinson’s disease, seizure disorder, and cerebral damage secondary to cerebrovascular accidents and anoxic brain injury. Determining the aetiology of RTD through a thorough history and physical examination is critical in achieving successful treatment outcomes.
The treatment of TMJ dislocation can be traced back as far as 16th century BC. The Edwin Smith Papyrus from ancient Egypt, the second oldest medical text in human history, described closed reduction: ‘You shall place your thumbs on the extremities of the two claws [rami] of the mandible, inside the mouth, and your other fingers under his chin. You cause [the rami] to move downward so they are put back in place’. This is not unlike the modern technique used to treat acute temporomandibular dislocations. Treatment methods employed for acute TMJ dislocation consist of closed reduction (with or without the use of local anaesthesia and intravenous sedation), immobilization (head wraps and maxillomandibular fixation), behaviour modification, and medications (non-steroidal anti-inflammatory drugs and muscle relaxants.)
Treatment of RTD can be categorized as alteration of the condylar path, alteration of the muscular and ligamentous attachments, tethering, or induced arthrofibrosis. Alteration of the condylar path is aimed at either removing the interference or creating an interference to limit the condylar path. Eminectomy and discectomy have been described to eliminate the interference of the articular eminence or meniscus. Condylotomy, first described for the painful TMJ, has also been described to create a favourable condylar path for RTD. There have been many variations of articular eminoplasty using bone grafts either as on onlay or an interpositional graft utilizing multiple donor sites including the zygomatic arch, rib, hip, cranial bone, and chin. Alloplastic materials have also been advocated for eminoplasty, including metal implants and hydroxyapatite blocks. Other modalities include down fracture of the zygomatic arch and anterior disk repositioning to produce a physical obstruction to translation.
Alteration of muscular and ligamentous attachments have also been described including capsulorrhaphy by plication or utilizing electrothermal and chemical modalities, lateral pterygoid myotomy, temporalis scarification, temporalis tendon redirection, and botulinum toxin injections into the lateral pterygoid. Tethering techniques have been described using wire, fascia lata, sutures, and temporalis fascia. Another method advocated is producing an induced arthrofibrosis by the injection of a sclerosing solution or autologous blood. The aim of this study is to review the safety and efficiency of arthroscopic electrothermal capsulorrhaphy for the treatment of RTD.
Materials and methods
The study included 11 consecutive patients treated for RTD between 2004 and 2010. The patients included in this retrospective study were treated non-surgically for RTD at least twice and continued to dislocate. Patients treated for other TMJ pathology (i.e. internal derangement) simultaneously or with a history of previous TMJ surgery were excluded from the study. Success was determined by the absence of any further dislocations.
The procedure was performed with the puncture technique as described by McCain using the Dyonics 2.0 mm operative system, the 1.7 mm TMJ arthroscope from Smith and Nephew, the McCain TMJ bipolar by Stryker, and in some cases a holmium laser. After establishing the fossa portal, the arthroscope was introduced and a needle inserted into the joint space for patent outflow. The diagnostic arthroscopic sweep was completed. Upon reaching the anterior recess of the joint, a second puncture was established using the vector system for triangulation into the most anterolateral aspect of the joint space. Once established, a straight probe was used to translate both cannulas into the posterior recess. The bipolar (20 W) cautery was then used to create deep lesional burns along the oblique protuberance. The lesions were then continued as far laterally as possible along the posterior capsule wall. Shrinkage of the synovium was observed arthroscopically and limited to approximately 15% change, as observed by the surgeon ( Fig. 1 ). In some cases the holmium laser was used in addition to the bipolar.
Immediately postoperatively the patients were placed into bilateral class I medium elastics on orthodontic cuspid brackets that had been placed preoperatively in the clinic. Medium elastics were used continuously for 3 weeks and at night only for an additional 3 weeks, a total of 6 weeks. Patients were instructed to maintain a full liquid diet for 72 h and a mechanical soft diet for 6 weeks. The operative time averaged 20 min per side.
Results
11 patients were treated between 2004 and 2010. There were 9 females and 2 males in the group with an age range of 17–97 years (mean 45 years). The treatment was bilateral in 8 cases and unilateral in 3 cases. Follow up varied between 6 months and 6 years, with an average of 27 months. Of the 11 patients treated, two recurrences were observed (82% success.) A 71-year-old female treated bilaterally began to have unilateral painful subluxation 2 months postoperatively. This patient was subsequently retreated with the same technique as well as arthroscopic autologous blood injection. Two months later it recurred again and she underwent an eminectomy procedure. She finally developed an ankylosing osteoarthritis and went on to have bilateral total joint replacements. An 80-year-old male treated unilaterally suffered continued dislocation and went on to have a unilateral discectomy and eminectomy. He no longer dislocates, but does complain of joint crepitation and intermittent pain on the operated side 5 months postoperatively. There were no other complications and all other patients reported normal function and diet within 3 months of surgery.
Case presentation
A 97-year-old female presented to the emergency room for closed reduction of a TMJ dislocation which occurred while sleeping. The emergency department physician had tried to reduce the dislocation unsuccessfully and then consulted the authors. The patient and daughter reported more than 30 previous dislocations over the past 3 years, with increasing frequency. The patient had been seen by several oral and maxillofacial surgeons and refused surgical intervention due to advanced age and compromised cardiovascular status. At this time she was sleeping with a head wrap and a soft cervical spine collar to prevent dislocations. The patient was reduced manually with intravenous diazepam for sedation and muscle relaxation. The patient and daughter refused any surgical intervention on follow up. After 3 more manual reductions in the emergency room by the authors’ service, the patient obtained medical clearance and underwent the procedure bilaterally. There were no complications and the patient has followed up for 19 months with no recurrence. Figs. 2 and 3 document the patient’s treatment.
Results
11 patients were treated between 2004 and 2010. There were 9 females and 2 males in the group with an age range of 17–97 years (mean 45 years). The treatment was bilateral in 8 cases and unilateral in 3 cases. Follow up varied between 6 months and 6 years, with an average of 27 months. Of the 11 patients treated, two recurrences were observed (82% success.) A 71-year-old female treated bilaterally began to have unilateral painful subluxation 2 months postoperatively. This patient was subsequently retreated with the same technique as well as arthroscopic autologous blood injection. Two months later it recurred again and she underwent an eminectomy procedure. She finally developed an ankylosing osteoarthritis and went on to have bilateral total joint replacements. An 80-year-old male treated unilaterally suffered continued dislocation and went on to have a unilateral discectomy and eminectomy. He no longer dislocates, but does complain of joint crepitation and intermittent pain on the operated side 5 months postoperatively. There were no other complications and all other patients reported normal function and diet within 3 months of surgery.
Case presentation
A 97-year-old female presented to the emergency room for closed reduction of a TMJ dislocation which occurred while sleeping. The emergency department physician had tried to reduce the dislocation unsuccessfully and then consulted the authors. The patient and daughter reported more than 30 previous dislocations over the past 3 years, with increasing frequency. The patient had been seen by several oral and maxillofacial surgeons and refused surgical intervention due to advanced age and compromised cardiovascular status. At this time she was sleeping with a head wrap and a soft cervical spine collar to prevent dislocations. The patient was reduced manually with intravenous diazepam for sedation and muscle relaxation. The patient and daughter refused any surgical intervention on follow up. After 3 more manual reductions in the emergency room by the authors’ service, the patient obtained medical clearance and underwent the procedure bilaterally. There were no complications and the patient has followed up for 19 months with no recurrence. Figs. 2 and 3 document the patient’s treatment.
Discussion
This procedure is a variation of the technique described by Ohnishi of posterior scarification with arthroscopic disk suturing, where the suture was used to limit condylar translation during the healing phase. The technical difficulty associated with arthroscopic disc suturing limited the numbers of practitioners able to apply this technique. By the use of elastics with orthodontic brackets as a form of ‘reverse’ physical therapy, sufficient immobilization is maintained for capsule and ligament healing without the need for disc suturing. This modification makes this procedure technically feasible for any practitioner comfortable with double puncture TMJ arthroscopic techniques and basic operative manoeuvres.
The classic description of TMJ anatomy as described by Rees in 1954 depicts a bilaminar zone (BZ) as the posterior attachment of the meniscus and a segment of posterior joint capsule independent from the BZ. Multiple studies have failed to identify a posterior segment of the joint capsule independent from the BZ. In essence, the posterior segment of the joint capsule corresponds to the BZ of the meniscus. Histologic analysis of the BZ under light and electron microscopy has confirmed this finding showing the composition to be predominantly type 1 collagen fibres with sparse type 3 collagen fibres. This fact is essential to understand the goal of this procedure, electrothermal shrinkage of the posterior TMJ capsule and attachments, effectively limiting forward translation of the mandibular condyle and ultimately dislocation or painful subluxation.
Electrothermal capsulorrhaphy is a well established modality in the orthopaedic literature for hypermobile joints. The use of thermal energy has been documented since it was used in the time of Hippocrates, when a hot probe was placed in the axilla to prevent shoulder dislocations. With the advancement of arthroscopic techniques as well as various electrothermal modalities it has gained popularity and success rates have been reported above 90%. The molecular and histologic effects of electrothermal energy on collagen fibres have been well studied in in vitro and in vivo studies. The microscopic changes within the tissues are attributed to unwinding of the collagen triple helix and fibril contraction resulting in a shortened state ( Fig. 4 ). This shortened collagen serves as a scaffold for fibroblasts which repair collagen with new matrix production. Within 90 days, tissues were shown to have regained their native structure at the new shortened state.
One of the challenges of this procedure is the lack of a discrete clinical endpoint for treatment. The orthopaedic application of this technique relies on visual changes of the tissue as well as gross capsular shrinkage intraoperatively. Studies have shown worsening biomechanical properties when more than 15–25% is induced, but return to normal biomechanical properties has been observed in 14 days. The need for postoperative immobilization has been studied in a rabbit models and shown to be essential to avoid lengthening of ligaments to pre treatment lengths. This was also studied retrospectively in humans undergoing glenohumoral capsulorrhaphy, where patients with poor postoperative compliance showed significantly worse clinical outcomes and an increased need for retreatment. Currently, most practitioners employ a period of 3–6 weeks of postoperative immobilization for this orthopaedic application. There are a variety of available electrothermal modalities that can be used arthroscopically, including bipolar, monopolar, and holmium laser. No studies have been performed to compare clinical outcomes of these modalities in the orthopaedic literature. It has been the authors’ clinical experience that more profound shrinkage can be obtained using the bipolar over the holmium laser. There is potential to adapt commercially available radiofrequency probes with temperature controlled settings to have an object endpoint for treatment as opposed to the estimation of shrinkage by the surgeon .
Arthroscopic electrothermal capsulorrhaphy is a minimally invasive procedure that is effective at treating RTD. The success rate of 82% (contradicts results section) for this procedure is commensurate with those established in the literature for emminectomy (74–100%) and for the zygomatic fracture blocking technique (67–100%). The limitations of this study include a small patient sample and retrospective design. It should be noted that all of the studies cited for other techniques suffer from the same shortcoming of a low number of patients due to the rarity of this pathology. Inherent to this procedure are all the benefits of arthroscopy over open arthrotomy, including lower incidence of facial nerve palsy and dysesthesias, less risk of inducing arthritic changes, possibility of an outpatient procedure, and less postoperative pain and joint noises. This procedure is best suited to cases of excessive capsular and ligament laxity where the condition can be addressed by electrothermal shrinkage of these ligamentous attachments. This mechanism of action explains a shortfall of this procedure, as seen by the two failures. Both patients had more advanced degenerative joint disease, stage 4 and 5 by the Wilkes classification. A prerequisite for this procedure to be effective is ligamentous attachments that would respond appropriately to capsulorrhaphy. Patients with advanced degenerative joint disease (Wilkes stage 4 and 5), will certainly be eliminated as candidates for this procedure in the future. If there is an underlying neuromuscular or psychological aetiology, this must be addressed by treatment with botulinum toxin, changing medication, or psychiatric counselling. Without treating the aetiology any improvement in joint laxity will be short lived due to the repetitive damage induced by movement disorders. In cases where the aetiology cannot be eliminated, a preferred method would be the Mitek anchor technique described by Wolford as it offers the advantages of being extracapsular as well as causing minimal damage to surrounding structures (eminence, temporalis). The results of this retrospective study support the use of this minimally invasive arthroscopic modality as a first line of treatment for RTD and painful subluxation prior to more invasive arthrotomy procedures, but further studies need to be undertaken to determine the effectiveness of this technique.
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