Preventive effect of intermittent cerebrospinal fluid drainage for secondary chronic hydrocephalus after aneurysmal subarachnoid hemorrhage

Background The efficacy of intermittent cerebrospinal fluid (CSF) drainage compared with that of continuous CSF drainage in patients with subarachnoid hemorrhage (SAH) remains undetermined to date. Therefore, we investigated whether intermittent CSF drainage is effective in reducing secondary chronic hydrocephalus (sCH) after aneurysmal SAH. Methods Overall, 204 patients (69 men and 135 women) treated for aneurysmal SAH between 2007 and 2022 were included in this study. Following SAH onset, 136 patients were managed with continuous CSF drainage, whereas 68 were managed with intermittent CSF drainage. Logistic regression analyses were used to calculate the age-adjusted and multivariate odds ratios for the development of sCH. The Cox proportional hazards regression model were used to compare the effects of intermittent and continuous CSF drainage on sCH development. Results Overall, 96 patients developed sCH among the 204 patients with SAH. In total, 74 (54.4%) of the 136 patients managed with continuous CSF drainage developed sCH, whereas 22 (32.4%) of the 68 patients managed with intermittent CSF drainage developed sCH. This demonstrated that the rate of sCH development was significantly lower among patients managed with intermittent CSF drainage. Compared with continuous CSF drainage, intermittent CSF drainage exhibited a multivariate odds ratio (95% confidential interval) of 0.25 (0.11–0.57) for sCH development. Intermittent CSF drainage was more effective (0.20, 0.04–0.95) in patients with severe-grade SAH than in those with mild-grade SAH (0.33, 0.12–0.95). Intermittent CSF drainage was ineffective in patients with acute hydrocephalus (8.37, 0.56–125.2), but it was effective in patients without acute hydrocephalus (0.11, 0.04–0.31). Conclusions Compared with continuous CSF drainage, intermittent drainage is more effective in reducing sCH after aneurysmal SAH. Although intermittent drainage was ineffective in cases of co-occurrence of acute hydrocephalus, it was effective in reducing sCH development regardless of the severity of initial symptoms at SAH onset.