Gross-total resection of Koos grade IV sporadic pediatric-spectrum vestibular schwannoma: A case report and review of the literature

Background: Sporadic, unilateral pediatric-spectrum vestibular schwannomas (PSVSs), which occur in patients 21 years or younger without a diagnosis of neurofibromatosis type 2, are rare tumors with an estimated incidence of less than 0.1/100,000 children. A subset of PSVS tumors (designated Koos grade IV PSVSs) exhibits significant brainstem compression and poses unique management challenges. Methods: A systematic review of the PubMed database was conducted for all case reports, case series, meta-analyses, and clinical trials involving patients with PSVS, along with one patient from our institution. Data related to patient demographics, tumor size, Koos grading, surgical approach, number of surgical resections, preoperative and postoperative House-Brackmann (HB) grade, and postoperative complications and treatment were recorded. Results: 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. Our technique of using an extended retrosigmoid craniotomy along with a navigated Sonopet ultrasonic aspirator facilitated a gross total resection with resolution of preoperative symptoms. Our literature review showed that 53.8% of Koos grade IV patients had a postoperative HB grade of III or higher, and a gross-total resection was only achieved in 57.1% of patients. Conclusion: This study illustrates the surgical complexity of Koos IV PSVS resection and underscores the need to further develop innovative surgical techniques (such as the use of a navigated ultrasonic aspirator and an extended retrosigmoid craniotomy as presented in this report) to improve surgical visualization and operative efficiency while decreasing neurologic morbidity.