Optimal timing of ventriculoperitoneal shunt insertion relative to cranioplasty post-decompressive craniectomy: a frequentist network meta-analysis

OBJECTIVE: Optimal timing of ventriculoperitoneal shunting (VPS) relative to cranioplasty (CP) after decompressive craniectomy remains controversial. VPS may be performed before, during, or after CP, but no consensus exists on which sequence minimizes complications. We performed a systematic review and network meta-analysis to compare the safety profiles of pre-, simultaneous, and post-CP shunting. METHODS: We searched PubMed/MEDLINE, Embase, and CENTRAL from inception to October 2025. Eligible studies directly compared at least two timing strategies in patients undergoing both CP and VPS. Primary outcomes included overall complications, reoperation, infection, and intradural bleeding. Secondary outcomes included shunt-related and other procedure-specific adverse events. We used a frequentist random-effects network meta-analysis with Mantel-Haenszel pooling. Transitivity and consistency were assessed using design-by-treatment interaction modeling and node-splitting. Certainty of evidence was graded using CINeMA. RESULTS: Ten observational studies met inclusion criteria, comprising 532 patients: 291 (54.7%) pre-CP VPS, 156 (29.3%) simultaneous CP-VPS, and 85 (16.0%) post-CP VPS. Simultaneous CP-VPS was associated with a significantly higher overall complication risk compared with post-CP VPS (RR 2.07; 95% CI 1.16-3.71; P < 0.05). Risk of reoperation (68/386, 17.6%), infection (62/532, 11.7%), and intradural bleeding (22/509, 2.8%) did not differ significantly across timing strategies. Secondary outcomes were infrequently reported and showed no statistically significant differences between groups. Inter-study heterogeneity and network inconsistency were low. Certainty of evidence for the main comparison (simultaneous versus post-CP VPS) was rated high. CONCLUSION: Simultaneous CP-VPS carried a higher composite complication risk than post-CP VPS, whereas staged strategies (VPS followed by CP or CP followed by VPS) demonstrated broadly comparable risk of infection, reoperation, and hemorrhage. These findings support a staged reconstruction paradigm in which CP is performed first to restore intracranial compliance and CSF hydrodynamics, with VPS reserved for persistent or progressive hydrocephalus rather than being routinely inserted at the time of CP.