Surgical Treatment of Small Vestibular Schwannomas via the Middle Fossa Approach: An Analysis of Hearing Preservation and Functional Outcomes

Abstract

Introduction: Vestibular schwannomas (VS) are benign tumors of the eighth cranial nerve. Advances in MRI diagnostics allow for detection at stages where preservation of hearing and facial nerve function is feasible.Aim: To analyze the outcomes of surgical treatment for small VS via the middle fossa approach (MFA) and to evaluate the correlation between pre- and postoperative hearing status.Materials and methods: The study included 66 patients (mean age 49.8 years) with small tumors, qualifying for removal via MFA. Hearing was assessed using pure-tone and speech audiometry (AAO-HNS scale), while facial nerve function was evaluated using the House-Brackmann (H-B) scale.Results: In patients with preoperative AAO-HNS class A or B, functional hearing (class A-B) was preserved in 40% of cases. Facial nerve function on the 7th postoperative day was graded I–III (H-B scale) in 85% of patients. The most common complication was cerebrospinal fluid leak (3%).Discussion: MFA provides excellent exposure for tumors smaller than 20 mm. While observation is a valid strategy, data suggest that only 34% of patients maintain hearing after 10 years without intervention. This study found no direct correlation between smaller tumor size and better hearing preservation, highlighting the complexity of cochlear nerve damage. However, only small tumors, that are manageable via MFA approach, were included in the study, which limits the ability to demonstrate the relationship between tumor size and hearing outcomes after treatment.Conclusions: The MFA approach ensures high tumor control, favorable facial nerve outcomes, and a satisfactory hearing preservation rate. It remains the recommended method for young patients with small lesions seeking definitive treatment.