Can early cranioplasty reduce the incidence of hydrocephalus after decompressive craniectomy? A meta-analysis

Background: Do alterations of cerebrospinal fluid dynamics secondary to decompressive craniectomy (DC) lead to hydrocephalus, and can this effect be mitigated by early cranioplasty (CP)? In this meta-analysis, we evaluated whether the timing of CP decreased the incidence of postoperative hydrocephalus. Methods: We performed a systematic search of PubMed/MEDLINE, Scopus, and the Cochrane databases using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for English language articles (1990–2020). We included case series, case–control, and cohort studies, and clinical trials assessing the incidence of hydrocephalus in adult patients undergoing early CP (within 3 months) versus late CP (after 3 months) after DC. Results: Eleven studies matched the inclusion criteria. The rate of postoperative hydrocephalus was not significantly different between the early (=96/1063; 9.03%) and late CP (=65/966; 6.72%) group (P = 0.09). Only in the three studies specifically reporting on the rate of hydrocephalus after DC performed to address traumatic brain injury (TBI) alone was there a significantly lower incidence of hydrocephalus with early CP (P = 0.01). Conclusion: Early CP (within 90 days) after DC performed in TBI patients alone was associated with a lower incidence of hydrocephalus. However, this finding was not corroborated in the remaining eight studies involving CP for pathology exclusive of TBI