Hannover Grading Scale

Classification of Samii (Hannover System).

see Hannover grading scale.

Classification system of the vestibular schwannoma

T1, purely intrameatal

T2, intra-extrameatal

T3a, occupying the cerebellopontine angle cistern

T3b, reaches the trunk of the brain (brainstem).

T4a, compresses the trunk of the brain

T4b, displaces the trunk and compresses the fourth ventricle.