Microsurgical Outcomes in Medium-Sized Vestibular Schwannomas: A Multi-Institutional Study Comparing Retrosigmoid and Translabyrinthine Approaches

Background: Vestibular schwannomas (VS) between 1.5 and 2.5 cm (i.e., medium-sized) in cisternal diameter present a unique challenge. Recent evidence suggests with increasing cisternal diameter between 1.4 and 2.0 cm the facial nerve and hearing outcomes decline with microsurgery. In this size cohort the hearing preservation is ~10%; therefore, hearing is often not a significant factor in surgical decision making. Given this, the choice between retrosigmoid (RS) and translabyrinthine (TL) approach is contentious with each skull base team having their own preference. In this series, we combined the microsurgical data between two high-volume VS centers with opposing approach biases for medium-sized VS to assess the difference between the approaches in extent of resection (EOR) and long-term facial nerve outcomes.