Novel Technique of Real-Time Sonopet Neuronavigation in Resection of Koos Grade IV Pediatric- Spectrum Vestibular Schwannoma: Case Report and Review of the Literature

Purpose Sporadic, unilateral pediatric-spectrum vestibular schwannomas (PSVSs) are rare cerebellopontine angle tumors with an approximate incidence of 1 case per 1,000,000 children annually. A subset of PSVS tumors (designated Koos grade IV PSVSs) exhibit significant brainstem compression and pose unique management challenges. Given the more aggressive biological nature often associated with PSVSs relative to adult vestibular schwannomas, it is critical to maximize cytoreduction while preserving adjacent neurovascular structures in this young patient population. Case Report We review the case of a 21-year-old female who presented with headaches, slight facial droop, and diplopia and was found to have a 3.7 cm Koos grade IV PSVS. Following an extended retrosigmoidal craniotomy, a novel technique utilizing real-time Sonopet neuronavigation was used to enhance the efficacy of intracapsular debulking prior to extracapsular dissection. We review the literature on Koos grade IV PSVSs and discuss the utility of novel, real-time Sonopet neuronavigation in this context. Conclusion In a literature review of patients with Koos IV PSVSs, 42.9% of patients underwent subtotal resection and 53.8% of patients exhibited postoperative facial weakness of House-Brackmann grade III or higher—illustrating the surgical complexity of these tumors. We believe the novel technique presented for real-time Sonopet neuronavigation may provide useful insight for future innovations able to improve operative efficiency and decrease neurologic morbidity associated with the resection of these complex skull base tumors.