Rectus sheath block for analgesia in open abdominal surgery: a systematic review, meta-analysis and trial sequential analysis

BACKGROUND: We aimed to evaluate the efficacy of rectus sheath block (RSB) for open abdominal surgery.METHODS: We searched PubMed/MEDLINE, Scopus, Embase, and Cochrane Library from inception until June 1, 2025, focusing on both cohort studies (CS) and randomized controlled trials (RCTs). Meta-analysis was restricted to midline laparotomy. The primary endpoint was resting pain scores at one, 12, and 24 hours postoperatively. The secondary endpoints included pain scores during movement/cough at the same timepoints and 24-hour opioid consumption. Standardized mean differences (SMDs) with corresponding 95% confidence intervals (CIs) were calculated.RESULTS: Fifteen RCTs and nine CS were included (N.=1638). RSB was associated with lower resting pain scores at one hour in both RCTs (SMD, -0-73, 95% CI, -1.24 to -0.22, P=0.005, I2 =69%) and CS (SMD, -1.01, 95% CI, -1.53 to -0.49, P=0.0001, I2=84%). From RCTs, resting pain was lower in the RSB group at 12 h (SMD, -0.85, 95% CI, -1.23 to -0.47, P<0.0001, I2=24%); and at 24 h, but only when the design was placebo-controlled (SMD, -0.67, 95% CI, -1.16 to -0.18, P=0.007, I2=0%). The type of comparator, local anesthetic infusion method, and urgency of surgery were the primary factors contributing to heterogeneity.CONCLUSIONS: RSB provides adequate early postoperative analgesia in midline laparotomy, but its clinical impact is modest and uncertain due to study heterogeneity and effect sizes that fall below a meaningful Minimal Clinically Important Difference.