Relationship between shunt-dependent hydrocephalus after subarachnoid haemorrhage and duration of cerebrospinal fluid drainage.

Subarachnoid haemorrhage (SAH) patients in Fisher group 3 have a high risk of vasospasm and chronic hydrocephalus. We have provided cisternal irrigation combined with a head-shaking method for preventing vasospasm in SAH patients. We investigated 76 SAH patients in Fisher group 3 who received cisternal irrigation with head-shaking to evaluate the relationship between the occurrence of hydrocephalus and various clinical factors, including duration of cerebrospinal fluid (CSF) drainage. Chronic hydrocephalus occurred in 25 patients (33%). The occurrence of hydrocephalus was associated with longer duration of CSF drainage (median, 13 days versus 9 days). By logistic regression analysis using significant factors, including age, preoperative neurological grade and Glasgow Outcome Scale, only the duration of drainage was independently associated with the occurrence of hydrocephalus (Odds ratio = 1.18 per day; 95% confidence interval, 1.02- 1.36). These results indicate that long duration of CSF drainage for preventing vasospasm may increase the occurrence of hydrocephalus.