Comparison between Coronoidotomy and Coronoidectomy in TMJ Ankylosis - A Prospective Study

Abstract

Objective: To evaluate and compare the efficacy, surgical efficiency, and complication profiles of coronoidotomy versus coronoidectomy as adjunctive procedures in interpositional arthroplasty for TMJ ankylosis.

Materials and Methods: In this single-center, randomized prospective study, 30 adult patients with unilateral or bilateral TMJ ankylosis were allocated equally into two groups: Group A (n=15) underwent coronoidotomy, while Group B (n=15) received full coronoidectomy. All patients underwent gap arthroplasty with temporalis fascia interposition, followed by early mobilization and standardized physiotherapy. Outcomes assessed included maximum interincisal opening (MIO) preoperatively, intraoperatively, and at 12 and 24 months postoperatively, operative time, intraoperative blood loss, and complications (including recurrence, malocclusion/open bite, facial nerve injury, and muscle dysfunction). A non-inferiority margin of 5 mm for MIO gain was used; statistical significance was set at p < 0.05.

Results: Both groups achieved significant improvement in MIO from baseline (mean gain: Group A +26.4 ± 3.5 mm; Group B +27.3 ± 3.7 mm; p<0.001). The between-group difference (+0.9 mm) fell within the pre-specified non-inferiority margin, demonstrating that coronoidotomy is functionally non-inferior to coronoidectomy. Operative parameters favored coronoidotomy, with significantly shorter mean operative time (2.2 ± 0.7 h vs. 3.5 ± 0.8 h; p < 0.001) and lower blood loss (110 ± 60 mL vs. 380 ± 240 mL; p < 0.001). Complication rates were low overall; coronoidotomy group exhibited fewer adverse events (one case each of open bite and re‑ankylosis) compared to the coronoidectomy group (three open bites, one facial nerve palsy, two persistent trismus), although differences were not statistically significant.

Conclusion: Coronoidotomy offers comparable long-term functional outcomes to coronoidectomy in TMJ ankylosis, while significantly reducing operative time and intraoperative blood loss, and trending toward fewer complications. These results support coronoidotomy as an efficient and lower-morbidity alternative to coronoidectomy in standardized arthroplasty protocols.