Hydrocephalus associated with vestibular schwannomas: perioperative changes in cerebrospinal fluid

Background Cerebrospinal fluid (CSF) protein levels are known to increase in patients with vestibular schwannomas (VS) with concomitant hydrocephalus, however the only information available on perioperative changes in CSF in these patients comes from case reports. Here, we investigated the relation between CSF protein and hydrocephalus in a large series of patients undergoing resection of VS. Method We classified 376 patients undergoing resection for VS at our institute into two groups, namely VS and no hydrocephalus (control, n=319) and VS with concomitant hydrocephalus (n=57), and compared clinical parameters. Among the 57 patients diagnosed with hydrocephalus, hydrocephalus status was examined by lumbar puncture in 20 patients with communicative hydrocephalus, and pre- and postoperative scores in CSF properties were compared. Results Patients in the hydrocephalus group were significantly older than those in the control group (mean, 55.8 vs. 43.8 years), and had a longer disease duration (median, 76 vs. 12 months), larger tumors (median, 15.6 vs. 5.5 ml), and a higher protein concentration in CSF (median, 147.3 vs. 65.1 mg/dl). Perioperative CSF samples of hydrocephalus patients showed a significantly decrease in cerebrospinal pressure after tumor removal (median, -75mmH2O), followed by a decrease in CSF protein (median, -74.5 mg/dl). No patients required the placement of a shunt. Conclusions Extended disease duration and elevated CSF protein secondary to the presence of a tumor contribute to the occurrence of hydrocephalus. Primary maximal tumor removal for VS with coexisting hydrocephalus avoids an unnecessary shunt.