Cerebrospinal Fluid Shunting in Hydrocephalus Secondary to Leptomeningeal Metastases: A Systematic Review and Meta-Analysis of Functional Outcomes, Symptom Improvement, and Complications

Background: Leptomeningeal metastasis (LMM) frequently leads to hydrocephalus due to impaired cerebrospinal fluid (CSF) flow, resulting in elevated intracranial pressure and debilitating neurological symptoms. CSF shunting including ventriculoperitoneal, lumboperitoneal, and other diversion procedures is widely used as a palliative strategy, yet current evidence remains fragmented, with limited quantitative synthesis of functional outcomes, symptom reversibility, survival, and complications. This systematic review and meta-analysis aimed to evaluate the clinical outcomes and safety profile of CSF shunting for hydrocephalus secondary to LMM. Methods: A comprehensive search of WOS, PubMed, Scopus, and Cochrane databases were conducted from inception to November 2025, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Eligible studies included patients undergoing CSF shunting for LMM-related hydrocephalus. Continuous outcomes were pooled using random-effects models, and binary outcomes were synthesized using generalized linear mixed-effects models. Median overall survival was pooled separately from time of diagnosis and time of shunt placement. Results: Twenty-three studies involving 1535 patients were included, of whom 812 underwent shunting. The pooled mean preoperative Karnofsky Performance Status was 55, with a postoperative improvement of 17 points. Symptom improvement after shunting occurred in 76% of patients, with high rates for headache (72%), nausea/vomiting (81%), and cranial nerve deficits (88%). Median overall survival was 9 months from LMM diagnosis and 5 months from shunt placement. Complications included infection (22%), shunt malfunction (16%), and subdural hematoma (4%). Conclusions: Pooled results showed that CSF shunting provides meaningful symptomatic and functional improvement for patients with LMM-associated hydrocephalus, although survival remains limited and complication rates are substantial.