Outcomes of External Ventricular Drainage, and Lumbar Drainage in Aneurysmal Subarachnoid Hemorrhage: A Systematic Review, and Meta-Analysis

Background: Lumbar drainage (LD) and external ventricular drainage (EVD) are used in patients with aneurysmal subarachnoid hemorrhage (aSAH) for cerebrospinal fluid diversion and blood clearance. While both have potential benefits, the relative efficacy and safety of LD versus EVD remain unclear, particularly given their use in differing clinical contexts. This study aims to provide a crude comparison of LD and EVD in the context of aSAH using the most updated and comprehensive meta-analysis. Methods: Following PRISMA guidelines, we performed a systematic review and pair-wise meta-analyses of 28 studies (4390 patients). Cohorts were analyzed across three contrasts-LD vs non-LD, EVD vs non-EVD, and LD vs EVD-using random-effects models. Outcomes included rebleeding, clinical vasospasm, delayed ischemic neurological deficit (DIND)/ischemic stroke, functional status (mRS 0-2 early and late; GOS ≤ 2), mortality, infection, and shunt dependency. Results: Compared with non-LD, LD lowered the odds of vasospasm (OR 0.51, 95 % CI 0.33 to 0.78), DIND/ischemic stroke (OR 0.55, 0.37 to 0.83), severe disability/vegetative state (GOS ≤ 2) (OR 0.28, 0.17 to 0.46), and mortality (OR 0.59, 0.41 to 0.85) without affecting rebleeding rates. Versus non-EVD, EVD reduced ischemic complications (OR 0.39, 0.16 to 0.96) but increased infection risk (OR 11.58, 1.45 to 92.71); vasospasm and rebleeding were similar. Direct comparison showed LD superior to EVD for early functional independence (OR 1.92, 1.06 to 3.50) and mortality (OR 0.49, 0.30 to 0.81), while rebleeding, vasospasm, infections, and shunt dependency were similar. Conclusion: LD was associated with lower rates of vasospasm, ischemic complications, severe disability, and mortality compared to non-LD, without increasing rebleeding risk. EVD reduced ischemic complications but was linked to higher infection rates. When directly compared, LD was favored for early functional recovery and survival. These findings should be interpreted in light of differing clinical indications and baseline severity. Further studies are needed.