Preservation of Hearing in Surgical Removal of Tumors of the Internal Auditory Canal and Cerebellar Pontine Angle

Abstract

In a presentation at the January 1987 Eastern Section Meeting of the Triological Society, the usefulness of intraoperative monitoring with electrocochleography and brain-stem evoked auditory potential was retrospectively examined in a review of 72 patients who underwent removal of unilateral tumor of the internal auditory canal and cerebellar pontine angle with attempts to preserve the cochlear nerve by Joseph B. Nadol, MD, and colleagues, of the Massachusetts Eye and Ear Infirmary, Boston. Preoperative and postoperative hearing levels were compared, as well as tumor size and status of intraoperative wave forms using evoked potentials. Facial nerve status was examined via electroneurography, and anatomic preservation of the facial nerve was recorded intraoperatively. These parameters were examined individually and in combination in an attempt to arrive at a method to aid in predicting the success of hearing preservation procedures in acoustic neuroma surgery. Hearing improvement was defined as a greater than 15% increase