Pretreatment and Posttreatment Factors Associated with Shunt-Dependent Hydrocephalus After Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis

-BACKGROUND: Hydrocephalus is a common complica-tion after aneurysmal subarachnoid hemorrhage (aSAH). This study aimed to evaluate novel preoperative and postoperative risk factors for shunt-dependent hydroceph-alus (SDHC) after aSAH via a systematic review and meta -analysis.-METHODS: A systematic search was conducted using PubMed and Embase databases for studies pertaining to aSAH and SDHC. Articles were assessed by meta-analysis if the number of risk factors for SDHC was reported by >4 studies and could be extracted separately for patients who did or did not develop SDHC.-RESULTS: Thirty-seven studies were included, comprising 12,667 patients with aSAH (SDHC 2214 vs. non-SDHC 10,453). In a primary analysis of 15 novel potential risk factors, 8 were identified to be significantly associ-ated with increased prevalence of SDHC after aSAH, including high World Federation of Neurological Surgeons grades (odds ratio [OR], 2.43), hypertension (OR, 1.33), anterior cerebral artery (OR, 1.36), middle cerebral artery (OR, 0.65), and vertebrobasilar artery (2.21) involvement, decompressive craniectomy (OR, 3.27), delayed cerebral ischemia (OR, 1.65), and intracerebral hematoma (OR, 3.91).-CONCLUSIONS: Several new factors associated with increased odds of developing SDHC after aSAH were found to be significant. By providing evidence-based risk factors for shunt dependency, we describe an identifiable list of preoperative and postoperative prognosticators that may influence how surgeons recognize, treat, and manage pa-tients with aSAH at high risk for developing SDHC.