Evaluation of The Gap Volume Following Temporomandibular Joint Ankylosis Surgery: A Preliminary Study

Objective: This retrospective study quantitatively evaluated linear and volumetric dimensions of the joint space created following gap arthroplasty (GA) and interpositional arthroplasty (IA) in temporomandibular joint ankylosis (TMJA) management, analyzing 10 patients (7 female, 3 male). Methods: Demographic, etiological, and surgical data were extracted from institutional archives. Pre- and postoperative cone beam computed tomography (CBCT) scans enabled joint space assessment, with linear measurements at anterior (AJS), superior (SJS), and posterior (PJS) joint spaces in coronal views. Three-dimensional volumetric analysis was performed using Mimics Innovation Suite Software. Results: GA demonstrated a mean interosseous distance of 5.92 mm (range: 3.56-9.78 mm) with corresponding space volumes ranging from 560.46 mm³ to 2194.66 mm³. IA showed mean interosseous distances at 6.85 mm (range: 2.8-11.83 mm), with volumetric measurements between 910.73 mm³ and 2738.08 mm³. All patients achieved clinically significant improvements in maximum interincisal opening, with a mean increase of 28.09 mm. Notably, no cases of reankylosis were observed throughout the mean follow-up period of 16.2 months. Conclusions: Both GA and IA effectively restored TMJ function, with early physiotherapy initiation being a critical success factor. While cost-effective, procedure selection should be individualized based on age, ankylosis type, and anatomical considerations. Although limited by sample size and follow-up duration, these findings validate both techniques, warranting further large-scale studies to establish definitive guidelines.