Longitudinal study of risk for facial nerve injury in mandibular condyle fracture surgery: marginal mandibular branch-traversing classification of percutaneous approaches.

OBJECTIVE: This study aimed to longitudinally assess the risk of facial nerve injury (FNI) in the surgical repair of mandibular condylar neck and subcondylar fractures (CN/SCFs) and to explore its predictors. MATERIALS AND METHODS: In a retrospective cohort study, the outcome was defined as FNI at 1 week and 1, 3, and 6 months postoperatively. Potential predictors included age, sex, etiology, fracture site and pattern (dislocation/non-dislocation), concomitant facial fractures, interval to surgery, surgeons' experience, plate types, and the marginal mandibular branch-traversing approach (deep/superficial group). We employed generalized estimating equations (GEEs) for repeated measurements throughout the 6-month follow-up period. RESULTS: Among 102 patients with 114 fractures, 27 patients (26.5%) developed FNI within 1 week. Prolonged FNI (>/= 1 month) occurred in 19 (19.2%) of 99 patients. Multivariate GEE analyses revealed that deep surgical approaches (i.e., traditional submandibular and retroparotid approaches; odds ratio [OR], 18.90; p = 0.011), fractures with dislocation (OR, 3.60; p = 0.025), and female gender (OR, 2.71; p = 0.040) were independently associated with the overall FNI risk. Additionally, the deep approaches (OR, 15.91; p = 0.014) and female gender (OR, 3.41; p = 0.035) were correlated with a prolonged FNI risk. Sensitivity analyses for the outcomes identified the same predictors. CONCLUSION: The predictors longitudinally associated with FNI in CN/SCF surgeries included a deep MMB-traversing approach, dislocated fracture, and female gender. CLINICAL RELEVANCE: The superficial surgical approaches (i.e., transparotid, transmasseteric anteroparotid, and high perimandibular approaches) should be adopted for CN/SCF treatment to minimize postoperative morbidity, especially for female patients with dislocated condyles.