Hearing Preservation, Facial Nerve Dysfunction, and Tumor Control in Small Vestibular Schwannoma: A Systematic Review of Gamma Knife Radiosurgery Versus Microsurgery

BACKGROUND AND PURPOSE: Vestibular schwannoma (VS) is the most common type of tumor found in the cerebellopontine angle that accounts for 8% of all intracranial tumors. VS management is currently a challenge due to the unpredictable nature of the tumor. Few studies have compared the results and complications of various therapeutic approaches to VS. Therefore, as a treatment option for VSs smaller than 25 mm, we conducted a systematic review to compare Gamma Knife radiosurgery (GKRS) with conventional surgery. METHODS: Literature searches were conducted of four online databases (PubMed, Google Scholar, Cochrane, and ScienceDirect) using the following keyword search: (“vestibular schwannoma” OR “acoustic neuroma”) AND (“gamma knife” OR “gamma knife radiosurgery”) AND (“resection” OR “open surgery”) AND (“hearing preservation” OR “facial nerve” OR “tumor growth”). RESULTS: We identified six retrospective cohort studies, five of which were of fair-to-good quality. All studies showed that GKRS was superior to surgery in hearing preservation. Two studies indicated that surgery was superior to GKRS in maintaining tumor control, one indicated that GKRS was superior, and the remainder indicated that there was no significant difference in maintaining tumor control between GKRS and microsurgery. CONCLUSIONS: Based on the three outcomes chosen for this review, GKRS was superior to microsurgery in small VS.