Efficacy of prophylactic antibiotics against meningitis after craniotomy: a meta-analysis.

OBJECTIVE Although prophylactic antibiotics have been shown by randomized clinical trials (RCTs) to help prevent deep infection after craniotomies, recent reports have suggested that antibiotics are not effective in preventing postcraniotomy meningitis. METHODS Data on meningitis as an end point from RCTs on prophylactic antibiotics for craniotomies were pooled in a random-effects meta-analysis. RESULTS Six prospective randomized trials or trial subgroups enrolling 1729 patients or operations were identified. Antibiotics reduced postoperative infection rates in five of the six RCTs; no trial individually showed a statistically significant benefit from antibiotics. The pooled odds ratio for meningitis with antibiotic treatment in the six RCTs was 0.43 (95% confidence interval, 0.20-0.92; P = 0.03). Subgroup analyses showed no detectable difference in antibiotic efficacy if antibiotics, with or without gram- negative coverage, were used or if the trial was single or double blinded. A sensitivity analysis showed modest dependence of the results of the analysis on the specific definition of postoperative meningitis used in interpreting trial results. CONCLUSION Prophylactic antibiotics administered before craniotomy reduce rates of postoperative meningitis by approximately one-half, a statistically and clinically significant benefit.