The method of deter- mining which patients require ventricular shunt placement was studied in a single-center, prospective, randomized, controlled trial in which 41 patients were randomized to rapid weaning of EVD (wean period 24 hours) and 40 patients were randomized to gradual EVD weaning (wean period 96 hours).245 There was no difference in the rate of shunt placement (63.4% rapid versus 62.5% gradual), but the gradual wean group had 2.8 more days in the intensive care unit (P 0.0002) and 2.4 more days in the A number of retrospective series have attempted to identify factors predictive of aSAH-associated shunt-dependent nonrandomized studies236,258 261 with 1718 pooled patients (1336 who underwent clipping, 382 who underwent coiling) found a lower risk of shunt dependency in the clipping group (relative risk, 0.74; 95% confidence interval, 0.58 0.94) than in the coiling group (P 0.01); however, only 1 of the 5 studies showed an independent significant difference.258 Three other nonrandomized series not included in the meta- analysis showed no significant difference between clipping and coiling in shunt-dependent chronic hydrocepha- lus.237,244,262 Fenestration of the lamina terminalis has been suggested to reduce the incidence of shunt-dependent chronic hydrocephalus, yet a meta-analysis243 of 11 nonrandomized studies234,260,263 271 pooled 1973 patients (975 who had un- dergone fenestration and 998 who had not) and found no significant difference in shunt-dependent hydrocephalus be- tween patients who had undergone fenestration of the lamina terminalis and those who had not (10% in the fenestrated cohort versus 14% in the nonfenestrated cohort; P 0.09). A nonrandomized study not included in the meta-analysis com- pared 95 patients who underwent aneurysm clipping, cisternal blood evacuation, and lamina terminalis fenestration with 28 comparable, non blood-cleansed, endovascular therapy treated patients and found that shunt-dependent hydrocepha- lus occurred in 17% of surgical patients versus 33% of patients treated with endovascular therapy (statistical signif- icance not reported).237 Management of Hydrocephalus Associated With aSAH: Recommendations 1. aSAH-associated acute symptomatic hydrocephalus should be managed by cerebrospinal fluid diversion (EVD or lumbar drainage, depending on the clinical scenario) (Class I; Level of Evidence B). 