Microsurgery for Acoustic Neurinoma—Lateral Position and Preservation of Facial and Cochlear Nerves

Twenty two cases of acoustic neurinoma were operated upon in the lateral position under an operating microscope during the past three years. Anatomical and physiological preservation of the facial nerve was successfully achieved in 19 cases. Electrical stimulation of the facial nerve using bipolar forceps proved to be very useful. Sound monitoring with tremorgraphy pick-ups on the face was designed for observation of facial movement driven by nerve stimulation. Hearing acuity could be preserved postoperatively in three large sized neurinomas with the aid of direct recording of action potentials on the cochlear nerve during surgery. Advantages of the lateral position and some instrumental improvements for surgery are discussed.