Surgical Management of the Internal Auditory Meatus in Retrosigmoid Approach for Vestibular Schwannoma Debulking and Excision

In this study, we compared two surgical techniques to open the posterior lip of the internal auditory meatus; 1st technique: using burr, 2nd technique using manual opening of the posterior lip of the internal auditory meatus with 2 or 3 mm, 45-degree angled Kerrison’ s upcuts.

Twenty cases of Vestibular schwannoma were involved in this study. They were equally divided between the 2 surgical techniques. In all cases both endoscopic assisted inspection of the internal auditory meatus and facial nerve monitoring were used.

Manual opening of the posterior lip of the internal auditory meatus using the upcuts saved an average of 30 minutes in the operative time, it also prevented mishaps related to high speed rotating head of the burr accidentally touching cottonoids covering the brain and at the same time did not increase the risk of facial nerve injury during cutting the posterior lip. The facial nerve was preserved in all the 20 cases involved in the study.

Endoscopic assistance reduced the need for wide opening of the meatus to debulk and deliver the intracanalicular component of the tumor. The usual site of the facial nerve inside the canal minimized the risk of its injury during the manual cutting of the posterior lip.