Single versus double burr hole in subdural hematoma: A Bayesian pairwise meta-analysis of hospital stay

Abstract

Subdural hematoma (SDH) is a common neurosurgical emergency typically treated with burr hole craniostomy. However, whether single burr hole (SBH) or double burr hole (DBH) techniques influence hospital stay remains unclear. The aim of this study was to compare SBH and DBH in terms of hospital length of stay using a Bayesian pairwise meta-analysis. A systematic search of PubMed, Scopus, Scilit, and Web of Science was conducted for records indexed up to May 29, 2025. Studies reporting hospital length of stay as the mean ± standard deviation (SD) for patients undergoing SBH or DBH were eligible for inclusion. Effect sizes were calculated as standardized mean differences using Hedges’ g and pooled using a Bayesian random-effects model with broad, plausible prior distributions that limited extreme estimates without overriding the observed data. Posterior summaries were presented as pooled effect estimates with 95% credible intervals (CrI), between-study heterogeneity (τ), posterior probability of direction, and sensitivity analyses with leave-one-out refitting.  Data from eight studies comprising 465 patients were pooled in the meta-analysis. The pooled standardized mean difference in hospital stays between SBH and DBH was -0.02 (95%CrI: -0.47 to 0.39), indicating no meaningful difference. Between-study heterogeneity was moderate (τ=0.37, 95%CrI: 0.02 to 0.96). The posterior probability that SBH led to longer hospitalization than DBH was 46%, and the Bayes factor (BF₀₁=2.3) favored the null hypothesis of no difference. In conclusion, the Bayesian analysis revealed no statistically significant difference in hospital length of stay between SBH and DBH.