Minimally Invasive Surgery at the Cerebellopontine Angle: Endoscopic-Directed Vestibular Neurectomy

Objective: The purpose of this study was to describe and evaluate the two-handed endoscopic-directed retrosigmoid approach for selective vestibular neurectomy (SVN) in patients with medically refractory Ménière's disease.

Methods: Ten patients underwent an endoscopic-directed retrosigmoid craniectomy with vestibular neurectomy using the Frazee II rigid advanced neuroendoscope for treatment of Ménière's disease. In all patients the identification and dissection of the VII/VIII nerve complex was performed entirely under endoscopic guidance. Vestibular nerve sectioning was completed with the endoscope in 5/10 cases (50%). In each endoscopic-directed operation the endoscope is utilized as a microsuction instrument in addition to a visualization tool. This allows for manipulation of the endoscope to always be executed by the primary operating surgeon without sacrificing bimanual dexterity.

Results: Vestibular neurectomy was completed in all 10 patients. Significant improvement in preoperative tinnitus and vertiginous episodes was achieved in 9/10 patients (90%). Auditory function was noted to be worse postoperatively in only one patient (10%). The same patient also developed a House-Brackmann grade III facial nerve palsy, which improved gradually over time. There were no further operative complications and no patient developed a delayed cerebrospinal fluid leak.

Conclusions: Endoscopic-directed vestibular nerve sectioning is a safe and effective surgical treatment option in patients with medically refractory Ménière's disease. Up until now the endoscope has been used primarily as an adjunct to the operating microscope in surgery at the cerebellopontine angle (CPA). In addition, previous endoscopic techniques typically require a third hand to manipulate the endoscope. With our endoscopic-directed approach, however, the endoscope is used throughout the operation exclusively, and only requires one operating surgeon. Advantages over the microscope include superior brightness, higher magnification, greater depth of field, and increased maneuverability within a small area. Among other things, this allows for minimally invasive openings, decreased cerebellar retraction, and improved visualization of nerve cleavage planes and vascular anatomy.