Interpositional Arthroplasty by Temporalis Fascia Flap and Galea Aponeurotica Combined With Distraction Osteogenesis: a Modified Method in Treatment of Adult Patients With Temporomandibular Joint Ankylosis and Mandibular Dysplasia.

Background: Interpositional arthroplasty (IPA) with temporalis fascia flap has been one of the most frequently performed procedures to treat temporomandibular joint (TMJ) ankylosis. However, recurrence often occurs when the flap lacks bulk or atrophies. Whether to perform IPA or distraction osteogenesis (DO) first has long been a controversial issue when patients presented mandibular dysplasia (MD). This study provided IPA a new graft material sufficient to prevent recurrence, combined the modified protocol of performing DO 6 months after IPA, and evaluated its efficacy in treating TMJ ankylosis patients with MD.

Methods: Six patients with unilateral TMJ ankylosis and MD were treated in the authors' study. The temporalis fascia flap and part of adjacent galea aponeurotica were filled the space after surgical release. Mouth-opening exercises started immediately post-IPA. Distraction osteogenesis was performed 6 months after IPA and had a 4-month consolidation. The maximum interincisal distance at preoperative, immediately post-IPA and the latest follow-up were recorded, as was the distraction length. The body mass index was measured at each patient's postoperative visit.

Result: All patients had significant improvements in facial aesthetic, mouth-opening, and occlusion. No major complication or recurrence was observed at 3 to 4 years' follow-up. The mean maximum interincisal distance was 4.83 ± 2.79 mm preoperative and 35.67 ± 3.39 mm at the latest follow-up. The mean distraction distance was 16.17 ± 5.98 mm. The body mass index improved from 17.33 ± 0.64 kg/m preoperative to 18.75 ± 0.60 kg/m before DO.

Conclusions: Temporalis fascia flap and adjacent galea aponeurotica as new graft materials are recommended for IPA. The modified staged treatment proved to be reliable and effective to prevent recurrence, improve mandibular length and final occlusion.