Fate of the Coronoid Process After Coronoidotomy and Its Effect on the Interincisal Opening: A Clinical and Radiologic Assessment

Coronoidotomy (surgical detachment of the coronoid process from the mandibular ramus) is used to treat several conditions, including coronoid hyperplasia and temporomandibular joint (TMJ) ankylosis. The stability of the outcome, however, is considered questionable because of the risk of reattachment of the coronoid process. This study aims to radiographically and clinically evaluate the long-term anatomic and physiological outcome after coronoidotomy. In 17 patients with unilateral TMJ ankylosis, 25 coronoidotomies were performed as an additional maneuver to relieve trismus after ankylosis release. Radiologic evaluation was performed immediately and 1 year postoperatively with panoramic radiography and computed tomography to assess changes at the coronoidotomy site. Clinical assessment included measurement of the interincisal distance at the 1-, 3-, 6-, and 12-month postoperative visits. A sharp osteotomy margin with a 3- to 10-mm gap between the ramus and coronoid process was observed immediately postoperatively in all cases. After 1 year, 23 cases (92%) showed partial (n = 5) or complete (n = 18) osseous union to the mandibular ramus, whereas in 2 cases, no evidence of fusion was observed radiographically. The mean interincisal opening achieved at 1 year was 33 mm. Coronoidotomy is an effective but more straightforward adjunct to arthroplasty than coronoidectomy (surgical excision of the coronoid process) in the management of TMJ ankylosis, with achievement and maintenance of adequate postoperative mouth opening.