MICROENDOSCOPY OF THE INTERNAL AUDITORY-CANAL IN VESTIBULAR SCHWANNOMA SURGERY

INTRAOPERATIVE MICROENDOSCOPY WAS performed for eight patients to acce ss the fundus of the internal auditory canal after retrosigmoid transm eatal surgery of vestibular schwannomas. The transmeatal procedure is usually limited laterally by the labyrinth block. The restricted openi ng of the internal auditory canal bears a potential risk of incomplete tumor resection. For eight patients with vestibular schwannomas, intr aoperative microendoscopy was performed after tumor resection to expos e the ''blind'' area of the internal auditory canal fundus. An excelle nt view of the fundus contents was obtained, including Cranial Nerves VII and VIII and the crista transversa. Tumor remnants were not observ ed in this series. Microendoscopy was shown to be an ideal adjunct to hearing-preserving transmeatal surgery of vestibular schwannomas, enab ling the removal of intracanalicular tumors with direct control of the lateral intracanalicular nerve portions.