Large vestibular schwannoma resection through the suboccipital retrosigmoid keyhole approach.

OBJECTIVE: The objective of this study was to retrospectively study the outcomes of large vestibular schwannoma resection through the suboccipital retrosigmoid keyhole approach and emphasize technical details and advantages of surgical resection of large vestibular schwannomas via this approach. METHODS: From January 2010 to September 2012, 37 consecutive patients (16 men and 21 women) with vestibular schwannoma, 4 cm or greater, received surgical resection through the suboccipital retrosigmoid keyhole approach in our department. Clinical records, radiographic findings, operative summaries, and follow-up data were analyzed retrospectively. RESULTS: The mean age of these patients was 45.1 ± 11.6 years. Thirty-six patients underwent primary keyhole surgical removal, and 1 underwent surgery for residual tumor after gamma knife. Gross total tumor removal was accomplished in 35 patients (94.6%), near total resection in 1 (2.7%), and subtotal resection in 1 patient (2.7%). The facial nerve was anatomically intact in all 37 patients (100%). Facial nerve function was assessed in 6 to 12 months after operation. Good function (House-Brackmann facial nerve grade I-II) was present in 81.1% of the patients, whereas acceptable function (grade III) was present in 11.1%. Cerebrospinal fluid (CSF) leakage that required surgical intervention occurred in only 5.4% of the patients, and meningitis occurred in 8.1%. In addition, 3 patients (8.1%) had hydrocephalus requiring a temporary ventricular diversion. There were no deaths. CONCLUSIONS: The suboccipital retrosigmoid keyhole approach is a valid choice for removing large vestibular schwannomas. Through this approach, cerebellopontine angle can be effectively exposed. Skills to protect facial nerve and extensive experience in microsurgical techniques can significantly improve the total resection rate and postoperative facial nerve function. The authors recommend this approach for patients with vestibular schwannomas larger than 3 to 4 cm.