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

Abstract

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. In a retrospective cohort study, the outcome was defined as FNI at 1week and 1, 3, and 6months 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. Among 102 patients with 114 fractures, 27 patients (26.5%) developed FNI within 1week. Prolonged FNI (≥ 1month) 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. The predictors longitudinally associated with FNI in CN/SCF surgeries included a deep MMB-traversing approach, dislocated fracture, and female gender. 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.