Anatomic Considerations for Temporomandibular Joint Vascularized Composite Allotransplantation

Concomitant temporomandibular joint (TMJ) transplantation is an obvious advancement in the reconstructive armamentarium for face transplantation in scenarios involving TMJ ankylosis. This study investigates the fidelity of mandibular morphology and explores the feasibility of bilateral mandibular condyle transfer in facial vascularized composite allotransplantation. Geometric analysis was performed on 100 skeletally mature maxillofacial computed tomography scans. Exclusion criteria included mandibular trauma and dentoalveolar disease. Parameters measured were posterior height, ramus tilt, anterior height, intercondylar widths, condyle height, coronoid height, interglenoid distances, symphyseal and gonial angles, condyle and glenoid volumes, and condyle shapes. Parameters were compared by gender and ethnicity using χ, independent sample t tests, and one-way ANOVA. Correlation with age was assessed using Pearson correlation coefficients. Bilateral measurements were compared using paired-sample t tests. Mean intercondylar width was 102.5 mm (SD 7.0 mm), anterior height 21.5 mm (5.5), and posterior height 65.3 mm (7.7), Males demonstrate larger geometric parameters, for example, intercondylar width (4 mm mean difference, P = 0.005), anterior height (2.3 mm, P = 0.032), posterior height (5 mm, P = 0.001). Asians demonstrated statistically larger intercondylar width (8 mm difference to Caucasians, P < 0.001). Increased age was associated with greater anterior height, gonial angle, and symphyseal angle; decreased glenoid height; and change in condyle shape. Despite significant disparity of laterality measurements within individuals, posterior height, glenoid, and condyle volumes are equivalent. Mandibular morphology is highly variable. However, transplantation of a facial allograft including the mandible and bilateral condyles is technically and anatomically feasible in patients with concomitant TMJ pathology.