Prognostic Factors of Long-Term Hearing Preservation in Small and Medium-Sized Vestibular Schwannomas After Microsurgery.

ABSTRACT

OBJECTIVE: The authors evaluated the long-term hearing outcomes of patients with vestibular schwannoma (VS) to explore appropriate surgical treatment. STUDY DESIGN: Retrospective study. SETTING: Tertiary referral center. PATIENTS A total of 138 patients diagnosed with small and medium-sized VS with serviceable hearing from January 2006 to December 2015. INTERVENTIONS: All patients underwent microsurgery via retrosigmoid (RSA) or middle cranial fossa approach (MFA) and were followed up for over 2 years. MAIN OUTCOME MEASURES: Pre- and postoperative hearing, including pure tone audiometry, speech discrimination score, and auditory brainstem response (ABR), were analyzed. RESULTS: The mean tumor size and volume were 16.6 ±â€Š3.4 mm and 1711.8 ±â€Š918.5 mm, respectively. Preoperative hearing levels were Class A in 42, Class B in 67, and Class C in 29 patients. Patients with a tumor from the superior vestibular nerve (SVN) had better hearing at diagnosis. Postoperative hearing levels were Class A, B, C, and D for 28, 17, 32, and 61 patients. Hearing outcomes were significantly better in patients with normal intraoperative I wave on ABR. Hearing loss within 6 months had a positive effect on postoperative hearing. Better preoperative hearing and tumors from SVN were correlated with better postoperative hearing outcomes. Tumor size, cystic variation, or extension to the fundus of internal auditory canal had no influence on hearing preservation. CONCLUSIONS: Better preoperative hearing, shorter hearing loss period, tumors from SVN, and normal intraoperative I wave are prognostic factors for serviceable hearing. RSA and MFA are effective and safe for tumor removal and hearing preservation.