Early postoperative pain and opioid use after liver surgery: A systematic review and meta-analysis.

BackgroundPostoperative pain following liver resection remains a clinical challenge, and the optimal analgesic strategy is still debated.ObjectiveTo determine whether a single intrathecal morphine injection provides superior analgesia and opioid-sparing effects compared with conventional systemic or regional techniques in adult patients undergoing liver surgery.MethodsPubMed, Embase, Web of Science citation index, and the Cochrane Library were searched from inception to August 2025 for randomized controlled trials comparing intrathecal morphine with alternative analgesic regimens in liver resection. The primary outcome was pain intensity at rest 24 h after surgery (standardized mean difference). Secondary outcomes included pain intensity at 48 and 72 h and cumulative opioid consumption within 24 h postoperatively. Random-effects meta-analyses and I² statistics were used to assess pooled effects and heterogeneity.ResultsEleven randomized controlled trials (n = 535) met the inclusion criteria. Intrathecal morphine reduced 24-h postoperative pain scores with a moderate effect (standardized mean difference = -0.64; 95% confidence interval: -0.84 to -0.44;