A comprehensive classification system of vestibular schwannomas

Because traditional classifications of vestibular schwannomas (according to relative size) cannot comprehensively describe lesions that grow in differ ent patterns after arising in regions as diverse as the cerebellopontine (G P) angle, the internal auditory canal, and the region lateral to the fundus of the internal auditory canal (labyrinth), we developed a new system to c lassify vestibular schwannomas, a system that describes the anatomical stru ctures involved by the tumour, rather than size alone. The vestibular schwa nnoma is classified first by location and then by extent. Our system provid es surgeons information helpful in choosing the surgical approach, in estim ating the difficulty of tumour excision, and in determining whether hearing might be preserved. Our system also avoids confusion and misunderstanding in discussions of treatment results because it reflects the diverse biologi cal characteristics of vestibular schwannomas. (C) 2000 Harcourt Publishers Ltd.