Curative Removal of Small Vestibular Schwannoma with Functional Preservation

Abstract

This video case presents techniques of retrosigmoid curative removal of small vestibular schwannoma (VS) with functional preservation. A 49-year-old woman with right intrameatal VS presented with sudden hearing loss. Preoperative hearing was American Academy of Otolaryngology-Head and Neck Surgery (AAO) class A (pure tone audiometry: 18 dB). Magnetic resonance imaging showed VS filling the right internal auditory canal (IAC). She underwent retrosigmoid suboccipital VS removal in lateral position using auditory brainstem response monitoring, resulting in total tumor removal with preservation of auditory brainstem response. No facial palsy occurred, and AAO class A (pure tone audiometry: 26 dB) hearing was preserved postoperatively. Techniques for curative tumor removal with functional preservation are as follows: 1) wide and deep IAC exposure with preservation of the meatal dura: though covered by the preserved meatal dura, meatal tumor bulges out after appropriate canal exposure, which also comprises petrous dura flap preparation and canal skeletonization; 2) sharp tumor debulking and dissection: tumor debulking is always mandatory to avoid damage to nerve function; 3) IAC reconstruction: after completion of tumor removal, the IAC roof is reconstructed using the petrous dura flap and muscle graft to restore the cerebrospinal fluid space in the canal and preserve long-term nerve function. Magnetic resonance imaging with gadolinium administration at 1 year and 5 years after surgery showed total tumor removal with no recurrence (i.e., curative tumor removal) and restored cerebrospinal fluid space in the canal by IAC reconstruction.