Abstract and Introduction
Abstract
Advances in neuroimaging have increased the detection rate of small vestibular schwannomas (VSs, maximum diameter < 25 mm). Current management modalities include observation with serial imaging, stereotactic radiosurgery, and microsurgical resection. Selecting one approach over another invites speculation, and no standard management consensus has been established. Moreover, there is a distinct clinical heterogeneity among patients harboring small VSs, making standardization of management difficult. The aim of this article is to guide treating physicians toward the most plausible therapeutic option based on etiopathogenesis and the highest level of existing evidence specific to the different cohorts of hypothetical case scenarios.
Hypothetical cases were created to represent 5 commonly encountered scenarios involving patients with sporadic unilateral small VSs, and the literature was reviewed with a focus on small VS. The authors extrapolated from the data to the hypothetical case scenarios, and based on the level of evidence, they discuss the most suitable patient-specific treatment strategies. They conclude that observation and imaging, stereotactic radiosurgery, and microsurgery are all important components of the management strategy. Each has unique advantages and disadvantages best suited to certain clinical scenarios. The treatment of small VS should always be tailored to the clinical, personal, and social requirements of an individual patient, and a rigid treatment protocol is not practical.
Introduction
Technological advances in neuroimaging have been responsible for changing the face of neurosurgery. This has certainly been true for VS, first described by Eduard Sandifort in the Netherlands in 1777. From what was considered a life-saving surgery (the finger extraction technique) done by Englishman Sir Charles Balance in 1894, VS treatment has evolved toward a more conservative management paradigm.
The common denominator for the evolution of VS treatment has been the focus on patients' quality of life. In the 1990s, achieving tumor control while preserving facial and cochlear nerve function were the ideal goals of surgery. The management of VS has developed further over the past decade, with importance being given to postoperative quality of life. This is even more pertinent to patients with small tumors (< 25 mm) or with minimal hearing deficits. Currently, the treatment options for managing small VS include conservative observation and serial imaging ("wait and scan"), stereotactic radiosurgery and microsurgery.
Formulating the best treatment strategy in patients with small tumors rests on the ability of the physician to understand specific patient and tumor characteristics and to be able to tailor the treatment options to the individual. The variability in the literature with respect to optimal treatment strategies for small VSs makes it even more challenging for the physician to formulate the most suitable plan. The main goal of this review is to outline the most suitable therapeutic option for different cohorts using hypothetical case scenarios and the highest level of evidence available. We list 5 hypothetical clinical situations and extrapolate from the reviewed literature pertinent to each clinical setting. Additionally, we discuss the proposed possible mechanisms of hearing loss in patients with small VSs.