Delayed Transient Facial Nerve Palsy in Acoustic Neuroma Surgery

Abstract

Introduction: Delayed facial nerve palsy following resection of acoustic neuroma is poorly described. The literature quotes a palsy rate of 15 to 29% in such patients. There appear to be two distinct time frames for the presentation of the delayed palsies: those occurring within the first 72 hours and those occurring at 5 to 10 days postoperatively. There are a number of proposed mechanisms. Methods: A review of patients presenting with delayed facial nerve palsy following resection was conducted. Features were identified as potential predictive factors for this phenomenon. Study population and absence of controls prevented appropriate statistical analysis. Results: Out of 120 acoustic neuroma patients operated on by one surgeon (RA) between September 2001 to July 2005, 8 patients (5 female, 3 male) were identified to have delayed facial nerve palsy (House-Brackmann grade ≥ 4). Age range was 26 to 62 years (mean age of 42).One patient had subtotal resection and 7 had gross total resection. Six underwent a retrosigmoid approach and 2 a middle fossa approach. In all patients, immediate postoperative facial function was HB grade 1 to 2. The delayed facial nerve palsy occurred between postoperative days 5 and 10 in 7 patients with gross total resection and within 72 hours of subtotal resection in 1 patient. Patients enjoyed rapid improvement in facial function within 8 weeks (grade 2 or better). Conclusion: Limited conclusions may be drawn at this stage. The timing of the palsy (5–10 days postoperatively) leads to the proposition that apoptosis through activation of capsases might be a considered mechanism. Potential treatment and prophylactic strategies are discussed.