전정신경초종환자에서 내이도내 신경의 국소해부학적 지식을 근거로 한 기능 보존 술식의 치료결과 분석

Abstract

Objectives: In this study, we classified the anatomical correlation of the facial nerve, vestibular nerve, and cochlear nerve along different locations of the internal auditory canal and analyzed the clinical outcome of hearing preservation surgery of vestibular schwannoma through the middle cranial fossa approach performed based on the anatomical study results. Methods: Cadaveric temporal bone dissection of 58 Koreans was performed and each nerve distribution pattern along the segment from the brainstem to the base of internal auditory canal was classified and schematized. Clinical application results were obtained from medical records of 14 patients who were diagnosed of tumor originating from the internal auditory canal and received mass excision via extended middle cranial fossa approach. Results: The cochlear nerve and vestibular nerve could be separated at porus of the internal auditory canal in only about 6% of our materials, but we could identify the facial nerve, vestibular nerve complex and cochlear nerve individually at the midportion in about 88%. Hearing preservation, which was achieved in 10 of 14 patients was more feasible when the tumor was of superior vestibular nerve origin with medial location in the internal auditory canal and when the patient had better preoperative hearing. Conclusion: Applying the above mentioned topographic anatomical information to the extended midcranial fossa approach, the vestibular nerve and the cochlear nerve could be separated by initiating the dissection at the mid-portion after exposing the internal auditory canal and consequently achieve favorable results of functional preservation including hearing.