Abstract
A case of long-standing dislocation of the temporomandibular joint (TMJ) complicated by growth and pseudo articulation with the base of the skull is described. The patient presented − more than 25 years after a traumatic event, with pain, facial asymmetry and malocclusion. A two-stage surgical correction was undertaken with preoperative embolization of the internal maxillary artery adjacent to the surgical site. The presenting features, stepwise progress and final results are illustrated and discussed. The treatment resulted in elimination of pain, restoration of occlusion and function and satisfactory facial appearance. This case, to our knowledge, represents the longest follow-up of TMJ dislocation with unique anatomic features as a result of overgrowth of the displaced condyle.
Highlights
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Long-standing TMJ dislocation causes discomfort, jaw deviation and malocclusion.
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If untreated long-dislocation may cause permanent changes in the TMJ anatomy.
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Although rare, the pseudo articulation may be formed to allow functional movement.
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Early intervention in acute or recurrent cases prevents future complications.
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TMJ replacement can be performed if minimally invasive procedures are ineffective.
Background
Temporomandibular joint (TMJ) dislocation occurs when the condyle is displaced out of the articular fossa and positioned beyond the articular eminence [ , ]. Acute TMJ dislocation refers to isolated episodes typically solved with non-surgical therapy without long-term sequelae [ ]. Dislocation may also occur repeatedly when the recurrent episodes become frequent [ ]. This is painful, impairing the ability to close the mouth and causing anterior open bite or lateral mandibular deviation [ , ]. If untreated chronic persistent dislocation may cause permanent pathological changes in the TMJ anatomy. This may be undiagnosed for months or years, thus becoming a long-standing dislocation [ ]. The condyle is displaced from its original position and lies anterior to the eminence, creating a new articulation described as pseudo articulation [ , ] between the posterior condyle and anterior slope of the eminence. Although rare, long-standing dislocation causes severe discomfort, facial asymmetry, mandibular deviation and malocclusion interfering with speech and mastication [ , , , , ].
Among all treatment modalities, manual reduction under local anesthesia should be initially attempted or conducted under general anesthesia if required. Other nonsurgical options comprise temporary intermaxillary fixation, injection of sclerosing agents or autologous blood into the TMJ, as well as botulinum toxin injection into the lateral pterygoid muscles [ ]. A variety of surgical procedures are available involving the condyle, capsule, articular disc, articular eminence, zygomatic arch, mandibular ramus and body, coronoid process and masticatory muscles [ , ].
This article presents a case of long-standing unilateral TMJ dislocation complicated by growth treated surgically to correct the malocclusion and reestablish function and facial symmetry.
Case presentation
A 38-year-old male sought care at the Massachusetts General Hospital (MGH) Oral and Maxillofacial Pain Center with complaints of severe pain in the face. The patient reported that at around the age of 10 he had been hit in the face with a soccer ball and his jaw was deviated to the left. He had sought medical attention but, no treatment was provided. At around the age of 22 he noticed the onset of pain in the right preauricular area.
Clinical examination demonstrated a grossly distorted lower face with marked deviated mandibular prognathism to the left, unilateral right Class III occlusion, anterior and left-sided cross bite, and prominent chin ( Figs. 1 and 2 ). The vertical mandibular range of motion was 54 mm with crepitus palpable in the right TMJ during motion. The lateral range of motion was 5 mm to the left and 0 mm to the right. There was pain to palpation over the right TMJ region and no pain during palpation of the masticatory and cervical muscles. The maxillary dental midline was 3 mm to the right of the facial midline and the mandibular dental midline was 18 mm to the left of the facial midline. A 3D-CT scan ( Fig. 3 ) indicated the presence of long-standing dislocation of the right mandibular condyle articulating with the greater sphenoid wing and anterior portion of the squamous temporal bone, hypertrophic remodeling of the mandibular condyle (measuring 2.5 × 3.2 cm). Clinical and imaging findings suggested a diagnosis of long-standing dislocation and mandibular deformity with subsequent growth and adaptation.
A single-stage approach was considered, however there was concern about the removal of the distorted condyle from the base of the skull and the thinning of the bone in the greater wing of the sphenoid and anterior part of the squamous temporal bone. In addition, the final anatomy of the mandible and possible modification of the fossa and eminence might affect the design of the custom prosthesis, thus two surgical stages were elected. The patient was referred to an Interventional Radiologist who determined that the right internal maxillary artery (IMA) was adjacent to the medial side of the enlarged condyle. The IMA was embolized prior to the first stage surgery to avoid the risk of extensive intra operative hemorrhage [ ]. Subsequently, a right TMJ arthroplasty with condylectomy and replacement of the right TMJ with a Synthes adjustable mandibular condyle reconstruction prosthesis (DePuy Synthes ® , West Chester, PA, USA) with abdominal fat graft was performed. Incisions were made in the preauricular and submandibular regions and a Nerveana ® nerve stimulator (Neurovision Medical Products Ventura, CA, USA) was used to monitor the facial nerve. A Piezo drill (DePuy Synthes ® , West Chester, PA, USA) was used to remove the right articular eminence and the entirety of the condyle in multiple pieces. The meniscus was found to be torn and was removed. The right coronoid was also dissected and removed. All the specimens were sent for histopathological examination. The patient was placed in maxillomandibular fixation with the dental midlines almost coincident and chin point symmetry much improved. The intermediate condylar prosthesis was then placed. Lastly, adipose tissue was harvested from the para umbilical region and transferred to the operative site to obliterate the dead space.
The condylar histopathology revealed cortical bone with degenerative changes, tendoligamentous insertion site and normocellular bone marrow with maturing trilineage hematopoiesis. At the first postoperative appointment, the patient was doing jaw-stretching exercises and reported no pain. One month after surgery his mouth opening was 36 mm and 6 months later it was 40 mm.
Seven months after the first surgery, the second surgical phase was performed. The temporary prosthesis was removed, and the right TMJ prosthesis TMJ Concepts System (TMJ Concepts, Ventura, CA, USA) was placed with abdominal fat graft and left sagittal split osteotomy as a relieving osteotomy-as indicated by the previous modeling for the custom made implant design to achieve the best possible occlusion. Two weeks post operatively the patient reported no pain and his maximal incisal opening was 25 mm, with bilateral excursions of 2 mm. At the 1-month and 3-month follow-up he was pain free and his maximal incisal opening increased to 30 mm and 41 mm, respectively, with bilateral excursions of 4 mm. At the 15-month follow-up, he had no pain with a maximal interincisal opening of 45 mm and bilateral excursions of 4 mm. In repose his right mandibular deviation was corrected ( Fig. 4 ). Intra-oral examination and post-operative panoramic showed normalization of his anterior and posterior occlusion ( Fig. 5 ).
