2025 Proffered Presentations
S175: CHARACTERIZING RATES OF POSTOPERATIVE HYDROCEPHALUS AFTER VESTIBULAR SCHWANNOMA RESECTION
Emily Chapman, MD; Alex Devarajan; Jack Y Zhang; Emery Monnig; Akhil Rao; Mehek Dedhia; Raj K Shrivastava, MD; ISMMS
Background: Hydrocephalus is a common comorbid presentation in patients with vestibular schwannoma (VS). However, postoperative hydrocephalus is a rare complication of surgical resection or radiosurgery which confers significant unexpected morbidity. Patients may require reoperation or a ventriculoperitoneal shunt (VPS) in refractory cases. There is little reporting or consensus on the incidence of postoperative hydrocephalus, which is subject to several confounding factors. We aim to characterize our institution’s experience with this complication and identify at-risk populations for its development.
Methods: A single-center retrospective review identified all patients presenting with a vestibular schwannoma from 2009 to 2020. Patients were stratified based on the presence of pre-existing or new-onset hydrocephalus after intervention. Tumors were measured on contrast-enhanced T1-weighted volumetric MRI, and volumes were approximated with the simplified ellipsoid method (ABC/2). Koos grades were assessed for degree of brainstem compression. Clinical, radiographic, and procedural data was reviewed. The modified frailty index (mFI-5), risk analysis index (RAI-C), and other frailty indices were calculated for all patients.
Results: Within the cohort, 194 patients received surgery, 112 patients received radiotherapy, 34 patients received both surgery and radiotherapy, and 366 patients were designated for observation with surveillance imaging. After intervention, 5 (2.57%) surgical patients, 1 (0.89%) radiosurgery patient, and 2 (5.88%) patients who received surgery and radiotherapy had postoperative hydrocephalus. Patients who required both modalities had a significantly higher risk of postoperative hydrocephalus (p=0.03). Initial brainstem compression on MRI and larger tumor volumes were significantly associated with risk of postoperative hydrocephalus in all patients who required surgery (p<0.001). Presence of a cystic tumor, body mass index, mFI-5, and RAI-C all did not confer any significantly increased risk of postoperative hydrocephalus across any modality of treatment.
Conclusion: Postoperative hydrocephalus remains as a rare complication of vestibular schwannoma management. Patients who require multiple modalities for treatment may be at greater risk to develop postoperative hydrocephalus as a complication. Larger tumor volumes and associated symptoms conferred increased risk of postoperative hydrocephalus even after resection.