Collagen Matrix Dural Repair for the Internal Auditory Canal in Retrosigmoid Vestibular Schwannoma Surgery.

Abstract

Drilling of the internal auditory canal (IAC) during vestibular schwannoma surgery carries a risk of cerebrospinal fluid (CSF) rhinorrhea due to mastoid air cell opening. Multilayer dural substitutes such as collagen matrix (DuraGen [Integra Life Sciences, Plainsboro Township, NJ, USA]) have been widely used in duraplasty, yet their application for posterior IAC wall repair has not been systematically evaluated. To describe a multilayer dural repair technique of the IAC using DuraGen and to present preliminary outcomes regarding its feasibility and safety for reducing postoperative CSF leakage. A retrospective review included 51 patients who underwent retrosigmoid vestibular schwannoma surgery with IAC drilling between January 2020 and March 2023. Mastoid air cell violation was classified as type A (craniotomy site + IAC) or type B (IAC only). All patients underwent bone wax sealing and multilayer DuraGen repair. Postoperative CSF rhinorrhea incidence was compared between groups. CSF rhinorrhea occurred in 2 patients (3.9%), both in type A (5.6%), with none in type B. The difference between groups was statistically significant, though interpretation is limited by the absence of a non-DuraGen control group. No major complications were observed. Multilayer DuraGen repair of the IAC wall appears to be safe and feasible, with a low CSF leak rate, particularly in type B patients. The extent of mastoid air cell exposure seems to be a key determinant of leak risk. Cost considerations vary internationally, and the findings should be regarded as preliminary. Prospective multicenter studies are warranted to confirm efficacy and cost-effectiveness.