Is it possible to totally resect an acoustic tumor and conserve hearing?

Over the last 19 years there has been increasing interest in the conservation of hearing while acoustic tumors are being resected. As enthusiasm has increased for the conservation surgery, so has controversy. The key to the controversy is a dissociation between gross anatomic and histologic observations. The purpose of this paper is to summarize our laboratory experiments and clinical observations in three areas: (1) Our experiments and observations suggest that it is probably not possible to totally resect an acoustic tumor medial to Scarpa's ganglion and conserve hearing. (2) It has not been possible to predict from preoperative auditory and vestibular function tests the number of fibers present within the cochlear and vestibular nerves lateral to the tumor, nor the number of fibers in small aggregates that may pass the tumor periphery. (3) If microscopic amounts of tumor are left behind, is that significant? It is too early to answer this question.