The purpose of this study was to establish the role of retaining the condyle and disc in the treatment of type III ankylosis, by clinical and computed tomography (CT) evaluation. A total of 90 patients with type III ankylosis met the inclusion criteria; 42 patients had left temporomandibular joint (TMJ) ankylosis, 27 patients had right TMJ ankylosis, and 21 had bilateral TMJ ankylosis, thus a total 111 joints were treated. Considerable improvements in mandibular movement and maximum mouth opening were noted in all patients. At the end of a minimum follow-up of 2 years, the mean inter-incisal mouth opening was 30.7 mm. Postoperative occlusion was normal in all patients, and open bite did not occur in any case because the ramus height was maintained through preservation of the pseudo-joint. Only three patients had recurrence of ankylosis, which was due to a lack of postoperative physiotherapy. The advantages of condyle and disc preservation in type III ankylosis are: (1) surgery is relatively safe; (2) the disc helps to prevent recurrence of ankylosis; (3) the existing ramus height is maintained; (4) the growth site is preserved; and (5) there is no need to reconstruct the joint with autogenous or alloplastic material. It is recommended that the disc and condyle are preserved in type III TMJ ankylosis.
Temporomandibular ankylosis is a condition in which the condyle is fused to the glenoid fossa by bony or fibrous tissue. Conditions such as trauma, infection, inadequate surgical treatment of the temporomandibular joint (TMJ) region, or systemic disease, may predispose the patient to ankylosis. In the past, no differentiation in the degree or type of ankylosis was made, and the aim of surgical treatment was just to create a gap between the condyle and the cranial base. In 1985 Sawhney classified TMJ ankylosis into four types according to the severity seen on a tomogram. In ankylosis type I, flattening or deformity of the condyle, with little joint space, is seen on the radiograph. At surgery there is minimal bony fusion, but there are extensive fibrous adhesions around the joint. This type is also called pseudoankylosis. In type II, there is bony fusion of the outer edge of the articular surface, but no fusion within the deeper area of the joint. In type III, there is a bridge of bone between the ramus and zygomatic arch. In these cases, after the bony bridge is excised, the upper articular surface and articular disc on the deeper surface remain intact. Also a condyle of reduced size and slightly medial to its normal anatomic position exists and is functional ( Fig. 1 ). In type IV, the entire joint is replaced by a mass of bone and the TMJ architecture is completely lost. Type III TMJ ankylosis is the most common type at our centre, perhaps because untreated condyle fractures are the most common cause of TMJ ankylosis, and in fracture, the condyle is most often medially displaced.
The commonly accepted surgical approach for the treatment of ankylosis includes total resection of the ankylotic bony mass, with special attention given to the removal of the medial aspect of the joint remnants in type III and type IV ankylosis. Precise reconstruction is needed for such an extensive resection of the joint in order to restore mandibular movement, restore the mandibular ramus height, improve the occlusal plane, and allow further mandibular growth in children. Among the various reconstruction techniques, the best established and most commonly used is an autologous costochondral graft. This technique requires special skill, a postoperative rehabilitation programme, and provides less than optimal results in most cases. Moreover the technique is associated with local (recurrence of ankylosis, rib resorption, rib overgrowth, fracture, osteomyelitis) and donor site (pneumothorax, osteomyelitis) morbidity.
If the location of the displaced condyle can be determined by computed tomography (CT) scan when dealing with ankylosis type III, it is possible to preserve, rather than eliminate, the condyle and disc. A retained condyle and disc could serve their role in mandibular function and growth and prevent the recurrence of ankylosis, in spite of their awkward shape and medial position. The purpose of this study was to establish the role of retaining the condyle and disc in the treatment of type III ankylosis, by clinical and CT evaluation.
Patients and methods
This study was conducted in a department of oral and maxillofacial surgery. Patients in all age groups with type III ankylosis according to the Sawhney classification, either unilateral or bilateral, who underwent surgery between May 2004 and March 2010, were included in the study. Exclusion criteria were: refused consent, medical contraindication for surgery, type I, II, and IV ankylosis, and cases of recurrence or previously treated ankylotic cases.
The chief complaint of the patient was severely limited mouth opening, resulting in difficulty in eating and speaking. Any history of facial trauma and the time at which opening became restricted was noted. When the event had occurred during the growth period, facial asymmetry was noted.
On clinical examination, maximal mouth opening was severely limited and associated with mandibular deviation towards the affected side. Condylar movements were not palpated and pain was not usually generated on palpation of the affected joint. The diagnosis was established on the basis of CT scans of the TMJ. The coronal reconstructions showed ankylosis on the lateral aspect of the medially displaced condyle ( Fig. 1 ). Based on the clinical and imaging findings, the following surgical approach was adopted. The ankylotic joint was accessed via a pre-auricular approach, which provided sufficient exposure. Guided by the various CT images, the resection was performed starting on the lateral aspect of the neck of the ankylosed stump, continuing to the condyle–stump notch ( Figs 2 and 3 ), while avoiding damage to the condyle and disc located in the medial aspect of the joint. The bony resection is far easier than the conventional method, as work is only carried out on the lateral side of the joint, so there is less chance of bleeding and the surgery is relatively safe. At this point, the displaced condyle and disc were seen, and both were freed from the surrounding tissues ( Fig. 4 ). The rest of the stump was contoured, creating a large gap between the glenoid fossa and the stump. Mandibular movement and mouth opening were checked at this stage. The disc was sutured lateral to the joint to cover the resection site and prevent recurrence of the ankylosis. No interpositional material was placed between the fossa and the condyle. An ipsilateral coronoidectomy was performed via the same pre-auricular approach and a contralateral coronoidectomy was performed via an intraoral approach if the intraoperative mouth opening was less than 30 mm. Postoperative antibiotics and analgesics were prescribed. On the third day, the patient started an intensive physiotherapy programme for rehabilitation of mandibular movements. Sutures were removed at 7–10 days postoperatively.
Patients were motivated to undertake intensive physiotherapy at home. Patients were followed up postoperatively at 1 month, 3 months, 6 months, 1 year, and 2 years, and if possible, for longer. At follow-up appointments patients were examined for inter-incisal mouth opening (mm), occlusion, and facial nerve paralysis, and underwent a CT scan ( Fig. 5 ).
A total of 90 patients with type III ankylosis met the inclusion criteria ( Table 1 ); 60 patients were male and 30 patients were female. In this study the mean age of patients was 14 years, ranging from 5 to 28 years. With regard to the site involved, 42 patients had left TMJ ankylosis, 27 patients had right TMJ ankylosis, and 21 had bilateral TMJ ankylosis, thus a total 111 joints were treated. On the basis of patient history, the aetiology of the TMJ ankylosis was trauma in 84 (93.3%) cases and unknown in six (6.7%) cases; most probably a trauma had been unnoticed in these six patients. From the patient history, the duration of illness or duration of TMJ ankylosis ranged from 2 years to 15 years, with a mean duration of 5.9 years. The duration of follow-up ranged from 2 to 7 years, with a mean of 3.2 years.
|Patient||Age (years)||Sex||Side||Aetiology||Pre-op opening (mm)||Post-op opening at 2 years (mm)|