Hydrocephalus Associated with Large Vestibular Schwannoma: Management Options and Factors Predicting Requirement of Cerebrospinal Fluid Diversion after Primary Surgery

ABSTRACT Objective: Obstructive hydrocephalus (HCP) related to vestibular schwannoma occurs in large tumors compressing the fourth ventricle. Symptoms related to HCP are expected to alleviate after resection of the tumor and decompression of the cerebrospinal fluid (CSF) pathways. However, some patients may require permanent cerebrospinal diversion even after surgery due to persistent HCP. In this study, the authors try to find out the factors associated with the requirement of CSF diversion after vestibular schwannoma surgery in cases of persistent HCP. Materials and Methods: This was a retrospective study involving 193 cases of vestibular schwannoma operated between 2010 and 2013 in our institute. Cases that underwent ventriculoperitoneal (VP) shunts before surgery were compared to cases which were operated directly. In cases where vestibular schwannomas were operated without prior VP shunts, factors which were associated with persistent postoperative HCP were analyzed. Results: Comparing the group who underwent direct surgery to the group who underwent VP shunt before definitive vestibular schwannoma surgery, the facial nerve preservation rates and surgical morbidity rates were comparable. In cases who underwent direct surgery, 10 out of 75 patients required postoperative permanent CSF diversion. Older age, male gender, duration of symptoms, larger tumor size, solid lesions, severe HCP, and clinical features of HCP were associated with postoperative requirement of CSF diversion but were not statistically significant. The most significant factor that correlated with the need for additional HCP treatment was the presence of postoperative hematoma of volume >10cc. Conclusions: Primary tumor removal is the optimal treatment for vestibular schwannoma associated with HCP. Postoperative hematoma may warrant close observation as these patients are at an increased risk of persistence of HCP.