Total one-stage suboccipital microsurgical removal of acoustic neuromas of all sizes: with emphasis on arachnoid planes and on saving the facial nerve

Abstract

Clinical suspicion is essential for early diagnosis of acoustic neuroma. No absolutely characteristic pattern of hearing loss occurs, and atypical presentations are the rule. The diagnosis of acoustic neuroma is possible by tests that can be performed on an outpatient basis. A hearing loss for high tones with impaired speech discrimination is frequently seen. Testing of the acoustic reflexes and particularly the brain stem auditory-evoked responses (BAER) are becoming the most reliable methods of defining hearing loss in patients suspected of having an acoustic neuroma. High-resolution, thin-sectioning, overlapping-cut CT scanning including CT pneumography when necessary and polytomography of the internal auditory meatus are the mainstays of radiologic evaluation. Complete removal of the tumor at one operation is usually possible by the suboccipital retromastoid route with preservation or restoration of normal brain stem function and preservation of facial nerve function. Preservation of hearing has occasionally been accomplished, and the potential occasionally exists for restoration of hearing in patients with favorable smaller tumors, which have not acquired extensive arterial supply in common with the cochlea. The two factors that most influence results are early diagnosis and gentleness of surgical manipulation of the tissues that is made possible by magnification and illumination with the operating microscope.