Facial Nerve Preservation Surgery for Koos Grade 3 and 4 Vestibular Schwannomas

BACKGROUND: Facial nerve preservation surgery for large vestibular schwannomas is a novel strategy for maintaining normal nerve function by allowing residual tumor adherent to this nerve or root-entry zone. OBJECTIVE: To report, in a retrospective study, outcomes for large Koos grade 3 and 4 vestibular schwannomas. METHODS: After surgical treatment for vestibular schwannomas in 52 patients (2004-2013), outcomes included extent of resection, postoperative hearing, and facial nerve function. Extent of resection defined as gross total, near total, or subtotal were 7 (39%), 3 (17%), and 8 (44%) in 18 patients after retrosigmoid approaches, respectively, and 10 (29.5%), 9 (26.5%), and 15 (44%) for 34 patients after translabyrinthine approaches, respectively. RESULTS: Hearing was preserved in 1 (20%) of 5 gross total, 0 of 2 near-total, and 1 (33%) of 3 subtotal resections. Good long-term facial nerve function (House-Brackmann grades of I and II) was achieved in 16 of 17 gross total (94%), 11 of 12 near-total (92%), and 21 of 23 subtotal (91%) resections. Long-term tumor control was 100% for gross total, 92% for near-total, and 83% for subtotal resections. Postoperative radiation therapy was delivered to 9 subtotal resection patients and 1 near-total resection patient. Follow-up averaged 33 months. CONCLUSION: Our findings support facial nerve preservation surgery in becoming the new standard for acoustic neuroma treatment. Maximizing resection and close postoperative radiographic follow-up enable early identification of tumors that will progress to radiosurgical treatment. This sequential approach can lead to combined optimal facial nerve function and effective tumor control rates.