External lumbar cerebrospinal fluid drainage in patients with aneurysmal subarachnoid hemorrhage: A systematic review and meta-analysis of controlled trials.

Introduction: External lumbar drainage is a promising measure for the prevention of delayed aneurysmal subarachnoid hemorrhage-related ischemic complications.

Methods: Controlled studies evaluating the effects of external lumbar drainage in patients with aneurysmal subarachnoid hemorrhage were included. Primary outcomes were: new cerebral infarctions and severe disability. Secondary outcomes were: clinical deterioration due to delayed cerebral ischemia, mortality, and the need of definitive ventricular shunting. Results were presented as pooled relative risks, with their 95% confidence intervals (95% CI).

Results: A total of 6 controlled studies were included. Pooled relative risks were: new cerebral infarctions, 0.48 (95% CI: 0.32-0.72); severe disability, 0.5 (95% CI: 0.29-0.85); delayed cerebral ischemia-related clinical deterioration, 0.46 (95% CI: 0.34-0.63); mortality, 0.71 (95% CI: 0.24-2.06), and need of definitive ventricular shunting, 0.80 (95% CI: 0.51-1.24). Assessment of heterogeneity only revealed statistically significant indexes for the analysis of severe disability (I(2)=70% and P=.01).

Conclusion: External lumbar drainage was associated with a statistically significant decrease in the risk of delayed cerebral ischemia-related complications (cerebral infarctions and clinical deterioration), as well as the risk of severe disability; however, it was not translated in a lower mortality. Nevertheless, it is not prudent to provide definitive recommendations at this time because of the qualitative and quantitative heterogeneity among included studies. More randomized controlled trials with more homogeneous outcomes and definitions are needed to clarify its impact in patients with aneurysmal subarachnoid hemorrhage.