[Microtopography of cerebellopontine angle structures in acoustic neuroma]

The structures of the cerebellopontine angle in neurinoma of the auditory nerve were studied in autopsy material and during surgical intervention with the use of an operative microscope. Principally different variants of the relationships between the cerebellopontine angle structures and the neurinoma capsule in intra- and extracisternal localization of the tumor were revealed. The greatest difficulties occur in exposure of the capsule of an intracisternal neurinoma which is tightly connected with the structures of the cerebellopontine angle by means of strong connective-tissue trabeculae. In extracisternal localization of the tumor its capsule is easily separated from the arachnoid, which is pushed to the brain stem, because there are no trabeculae between these structures. The main source of blood supply to the tumor irrespective of its localization is the anterior inferior cerebellar artery.