Management of Small Vestibular Schwannomas

Abstract

neuroma, is a benign nerve sheath tumor that arises from the Schwann cells of the superior and inferior branches of the vestibular nerve (cranial nerve [CN] VIII). VS accounts for 80% of cerebellopontine angle tumors and 8% of all intracranial tumors. VS has a clinical incidence of 1 case per 100,000 population. The increased availability of MRI has resulted in an increased incidence of VS, a smaller average tumor size at diagnosis, and an improved baseline hearing status at diagnosis. In addition, recent studies have improved our understanding of the natural history of these tumors. The results of the widespread application of radiosurgery as a primary treatment modality are becoming available, and the microsurgical technique has reached maturity. These variables, and the successes and shortcomings of the various available treatment options, require a nuanced approach to the management of patients with VS, particularly those with small tumors limited to the internal auditory meatus or less than 1.5 cm in greatest dimension. Treatment paradigms for small tumors are focused on the preservation of neurologic function. Presenting symptoms of patients with VS typically include hearing loss, tinnitus, vertigo, and unsteadiness. Although vestibular dysfunction can result in significant disability, comparative data are sparse regarding vestibular outcomes among treatment options. Most studies focus on tumor control, facial nerve (CN VII) function, and hearing outcomes. Recent studies have also included quality-of-life surveys. This article summarizes outcomes for the 3 management options of microsurgery, radiosurgery, and observation, and it suggests a management algorithm for patients with a small VS.