A comprehensive classification system of vestibular schwannomas.

Because traditional classifications of vestibular schwannomas (according to relative size) cannot comprehensively describe lesions that grow in different patterns after arising in regions as diverse as the cerebellopontine (CP) angle, the internal auditory canal, and the region lateral to the fundus of the internal auditory canal (labyrinth), we developed a new system to classify vestibular schwannomas, a system that describes the anatomical structures involved by the tumour, rather than size alone. The vestibular schwannoma is classified first by location and then by extent. Our system provides surgeons information helpful in choosing the surgical approach, in estimating 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 biological characteristics of vestibular schwannomas.