Predictors of Facial Nerve Involvement and Outcomes in Combined Temporal Bone and Parotid Surgery

ABSTRACT Objectives In cases of advanced parotid and skin cancer of the periauricular region, external ear, or ear canal, parotid surgery is combined with otologic procedures. There is limited data in this patient population regarding preoperative predictors of facial nerve (FN) tumor involvement and how this impacts recurrence and survival. The objective of this study is to review our institution's experience with patients who undergo parotidectomy and mastoidectomy/lateral temporal bone resection. Methods A retrospective chart review was performed of patients treated with combined parotidectomy and otologic surgery at a single institution over a 20‐year period. Results Of the 53 patients identified, 26 (49.1%) underwent FN preservation and 27 (50.9%) underwent FN sacrifice. Nine patients (17.0%) had a positive intraoperative nerve biopsy and 4 (7.5%) did not achieve tumor clearance. Higher rates of FN sacrifice were observed in patients with preoperative House–Brackmann (HB) II–VI (17/19; 89.5%) as compared to patients with HB I (7/31; 22.6%). HB scores were predictive of FN sacrifice and involvement on pathology (AUC = 0.829 and 0.913, respectively) whereas imaging was not predictive of FN sacrifice or involvement (AUC = 0.665 and 0.571, respectively). Additionally, intraoperative nerve biopsy was a prognostic factor for local recurrence ( p = 0.045) but did not affect survival ( p = 0.247). Conclusion There are few prognostic indicators for FN tumor involvement besides clinical exam; FN weakness is the main predictor of FN sacrifice. When the FN is involved, more extensive surgery is likely performed, which is beneficial given that overall survival is not significantly affected by nerve involvement. Level of Evidence 4.