Long-Term Dislocation of the Mandible: Is there an Algorithm to Success? Intraoperative Decision and Review of Literature

Abstract

Purpose

Long-term TMJ dislocation is a rare condition. It occurs when an acute luxation remains untreated in time.

Methods

A 52-year-old man presented with a long-term TMJ luxation in the context of Steinert’s disease. A discectomy together with condylectomy and eminectomy was performed, obtaining an adequate reduction of the luxated condyle and disc.

Results

Twelve months after the operation, the condition has not recurred at all. A stable and centred occlusion was checked; his MIO was over 30 mm.

Conclusion

The combination of these three techniques could be a good option in cases of Steinert’s myotonia, where the condyle luxation becomes chronic and irreducible due to the altered neuromuscular condition. There is still no consensus regarding the treatment for long-term TMJ dislocations. New and more solid studies may be needed in order to find adequate treatment protocols for this condition.

Introduction

Temporomandibular joint (TMJ) luxation consists in the displacement of the mandibular condyle out of the glenoid fossa. If this occurs, the normal relationship between the articular elements is lost and the condyle remains blocked in its new position [1]. TMJ luxation diagnosis is a clinical and a radiologic one. In the case of an anterior movement, the condyle is anterior and superior to the lowest point of the temporal eminence [1]. There are many etiopathogenic factors which may favour the development of a TMJ luxation that have been widely described [1].

In the beginning, TMJ luxation is an acute process, but it may eventually become recurrent or remain in time turning into a chronic luxation. Myotonic or neurological illnesses such as Huntington’s disease, epilepsy or Parkinson disease and muscle dystrophies and dystonias such as Steinert’s disease or Meige’s syndrome have been described as predisposing factors for the development and maintenance of a long-term TMJ dislocation as well as long-period intubations in patients admitted in intensive care units. Connective tissue diseases could also be involved in the development of this clinical entity [2]. Continuous damage to the articular elements leads to a situation that favours recurrence or TMJ blocking in a luxated position [1, 3–8]: changes in the condyle anatomy, as well as the presence of fibrous tissue inside the glenoid cavity secondary to a maintained inflammatory situation.

Long-term TMJ luxation is a very rare condition in our environment. It is described as that which has not been reduced in a period of more than 4 months, in contrast to recurrent luxation [3]. There is no agreement regarding its definition, clinical course or treatment. It has been observed that the duration of the luxation is a prognostic factor affecting its management [3–5, 7, 8]. In this study, we describe a case of long-term TMJ dislocation and review different treatment options which have been proposed.

Clinical Case

A 52-year-old man was referred by the neurologist with a possible long-term maintained TMJ luxation in the context of a myotonic dystrophy type I (DM1), also known as Steinert’s disease, diagnosed 3 years before. He was not under any chronic drug treatment. Clinical exploration showed an inability to close his mouth. The patient lived in a rest home due to family reasons, and his caregivers reported his mandible had been in that situation for more than 3 months. No mandible trauma was reported.

Both orthopantomography (OPG) and TMJ magnetic resonance imaging (MRI) (Figs. 1, 2) showed a complete left mandibular condyle luxation. There were no alterations concerning the right TMJ. This dislocation had never been reduced before. Conservative and manual techniques could not help reducing the articular elements; thus, open surgical management was decided. The main goal of the treatment was to restore TMJ biomechanics.

Fig. 1.

a Pre-surgical OPG showing complete luxation of left mandibular condyle. b Post-surgical OPG

Fig. 2.

Up: right and left TMJ, closed mouth position. Down: right and left TMJ, open mouth position

Under general anaesthesia and nasotracheal intubation, preauricular approach and arthrotomy were performed. An anteromedial luxation of the mandibular condyle was found, while the reduction of the condyle was not possible (Fig. 3). Thus, the articular capsule was opened and the inflammatory tissue in the gleno-temporal space was removed (Fig. 4). Reduction of the condyle remained impossible; then we applied discectomy, detachment of pterygoid muscle in condylar and capsular region and high condylectomy. There was still no space for the condyle, so we performed eminectomy following the Myrhaug procedure [5]. Arthroplasty and bone remodelling were performed (Fig. 5). A proper mobility of the condyle with an adequate settlement of the condylar head in the glenoid fossa was then checked. The histologic study of the condyle following surgery showed hypertrophic fibrous tissue in the articular layer (Figs. 6, 7).

Fig. 3.

After the preauricular approach, we could observe the fibrous tissues surrounding the luxated condyle and conforming the “neoarthrosis”. The condyle not be reduced

Fig. 4.

The articular capsule was opened, and the inflammatory and fibrous tissues in the gleno-temporal space were removed

Fig. 5.

Eminectomy, discectomy and high condylectomy were performed in order to increase the articular space

Fig. 6.

Fibrous tissues found in the specimens removed. We can appreciate large thickness of these tissues and the growth of vessels

Fig. 7.

The histologic study of the condyle following surgery showed hypertrophic fibrous tissue in the articular layer

The patient was discharged 2 days after the operation with no incidences or complications. We did not perform intermaxillary fixation. A week after, we perceived a stable and centred occlusion, his MIO being 36 mm. Twelve months after the operation, the condition has not recurred at all, while the patient is completely asymptomatic and fully functional.

Discussion

TMJ luxation is considered “long term” when it remains untreated in time [3]. When this situation occurs, spasm of the masticatory muscles as well as changes in the TMJ soft tissues such as fibrosis or scarring secondary to the maintained inflammatory situation takes place, affecting the articulation biomechanics and complicating its management [2–4]. The literature even describes the formation of a “false joint” anterior to the eminence in long-term luxations standing for more than a year. This would consist of a neoarthrosis which would allow some movements in space [5, 6]. The pathogenesis and clinical course of this entity are still to be explained. In our case, the histologic study of the removed tissues described hypertrophic fibrous tissue in the articular layer replacing the fibrocartilage. We could appreciate large thickness of these tissues and the growth of vessels.

We consider three main objectives when facing the treatment of long-term TMJ luxations: (1) to reduce the condyle, (2) to obtain appropriate functional results and (3) to avoid relapse and complications. Longer-term dislocations need more complex procedures in order to reduce the dislocated condyle in a damaged TMJ [3, 5, 7]. Surgery is considered an appropriate therapeutic alternative in the treatment of chronic TMJ luxations once the conservative treatment has failed or is not indicated [7, 8]. Arthroscopy is considered a reliable initial surgical option; this minimally invasive procedure may be used for diagnosis as well as for treatment in acute and chronic cases with predictable results [1]. TMJ open surgical procedures can be classified into two groups: (1) those aiming at reduction and (2) those giving reinforcement to the damaged articulation. Different options are available to effectively reduce the condyle and disc: myotomy, condylotomy, condylectomy, discectomy, eminectomy [3, 7–15]. Midline mandibulotomy has also been proposed as a reliable option for long-term TMJ luxation management [16, 17]. Total TMJ replacement may be considered when all other surgical options are found useless in restoring the articulation biomechanics [1].

Surgical treatment of TMJ luxations in patients suffering severe muscular spasm in the context of myotonic or neurological diseases is controversial [2]. In the present case, we decided to combine discectomy, condylectomy and eminectomy with the objective of increasing the articular space. Ours was a stepped approach. Applying this triple technique was an intrasurgical decision given the poor results obtained with more conservative options and the severe myotonia and scarring of the articular tissues. Twelve months after the surgery, the condition has not recurred at all. The ultimate goal by using a triple therapy is to release traction by hypertonia and increase the space in the joint. To our knowledge, this is the fifth reported case in which this triple therapy is used after Marqués-Mateo et al. applied it for treating a 50-year-old male who suffered a 4-month-long TMJ luxation after a long-period intubation [4] and Segami et al. applied it for three long-standing TMJ luxations [8].

No algorithm which clearly brings together viewpoints towards long-term surgical dislocation is available at the moment [5, 8]. For most of the authors, reduction by traditional manual methods should be the first approach to the management. In 2011, Huang et al. suggested open reduction was needed for dislocations remaining untreated for more than 4–12 weeks [3]. Other authors have proposed other treatment protocols [8]. It has been observed that the longer the luxation remains untreated, the more complex procedures may be needed to success in its management [7, 8]. This progressive difficulty in the management could be derived from the soft tissue histologic changes which have been described and which would be secondary to a maintained long-term luxation of the condyle. Unfortunately, the literature regarding this entity consists of a few case reports and there is no consensus regarding treatment. Güven recently published his review on the reported long-term dislocation cases and the treatment modality applied, showing that same treatment modalities are not suitable for different patients with similar clinic situations [5]. Segami et al. [8] published the largest report so far to our knowledge describing different surgical methods and indications.

A better understanding of the physiopathology of long-term TMJ luxations is required in order to elaborate a more appropriate treatment protocol. The literature is not clear on when does a luxation become “long term”. We think this would be when the soft tissue changes take place and the neoarthrosis [5] appears.

Conclusion

There is no consensus regarding the treatment of long-term TMJ dislocation. The combination of condylectomy, discectomy and eminectomy may be a reliable option for patients with muscular hypertonia, such as Steinert’s myotonia, in which condylar luxation may become chronic and irreducible. Further studies with large series are needed in order to reach an agreement concerning the definition and the most appropriate treatment protocol for long-term TMJ dislocation.