Histological considerations of the cleavage plane for preservation of facial and cochlear nerve functions in vestibular schwannoma surgery

Based on these histological observations, complete tumor resection can be achieved by removal of both tumor parenchyma and tumor capsule when a clear border between the tumor capsule and facial or cochlear nerve fibers can be identified intraoperatively. Conversely, when a severe adhesion between the tumor and facial or cochlear nerve fibers is observed, dissection of the vestibular nerve-tumor interface (the subcapsular or subperineurial dissection) is recommended for preservation of the functions of these cranial nerves.