Diagnosis and choice of surgical methods on traumatic temporomandibular joint ankylosis.

PURPOSE: The purpose of this study was to explore the diagnosis and operative methods for traumatic temporomandibular joint ankylosis. METHODS: Fourteen patients (8 females, 6 males; aged from 7 to 23 years, median age 17.5 years) with traumatic TMJ ankylosis of 1 to 15 years' duration, with a maximal mouth opening(MMO) from 0 to 1.0cm (average:0.46cm) preoperatively were included in this study. They were further divided into two types (I and II) based on false articulation medial to the analysis as shown by coronal computed tomography (CT) coronoid scan. 7 TMJs were treated with medial arthroplasty(MA), in which the lateral fusional bone was removed and the medial false articulation was retained for type I, 6 TMJs were treated with natural positional arthroplasty(NPA) in which the bony fusion between the condyle and glenoid fossa was separated and shaved, the disc was retained and repositioned for type II. Follow-up was carried out and the surgical effect was assessed based on clinical and imaging findings. Student's t test was conducted for comparison with SPSS15.0 software package. RESULTS: There was 9 TMJs from 7 patients for type I and 5 TMJs from 5 patients for type II as shown by CT. The mean postoperative MMO was 3.12cm, and the condylar shape was smooth on CT scan. There was significant difference between preoperative and postoperative MMO, P<0.01. There was no significant difference between MA and NPA, P>0.05. CONCLUSIONS: It is concluded that type I is more common in traumatic TMJ ankylosis than type II. The surgical effect of MA and NPA is good, with less injury, and is worthy of wide application. [ABSTRACT FROM AUTHOR]