Background: The transversus abdominis plane (TAP) block is a regional anesthesia  technique increasingly used for postoperative pain management in abdominal and  pelvic surgeries. Although its use has expanded in recent years, questions remain regarding its comparative effcacy, safety, and optimal clinical application.
Objective: To evaluate the effectiveness of TAP blocks in reducing postoperative  opioid consumption and pain scores, as well as in minimizing opioid-related adverse events compared with systemic analgesia or placebo.
Methods: A systematic review and meta-analysis of randomized controlled trials (RCTs) published between 2010 and 2023 was performed. Primary outcomes were  24-hour opioid consumption [in morphine milligram equivalents (MME)] and pain scores [measured on a Visual Analog Scale (VAS)]. Secondary outcomes included  the incidence of adverse events such as nausea, vomiting, and local anesthetic systemic toxicity (LAST). Database searches were conducted in PubMed, EMBASE,  the Cochrane Library, and   linicalTrials.gov. Two independent reviewers extracted  data and assessed study quality using the Cochrane Risk of Bias Tool 2.0. Data were  pooled using a random-effects model (RevMan 5.4), with mean differences (MD) reported for continuous outcomes and risk ratios (RR) for dichotomous outcomes. Results: Forty-fve RCTs comprising 5,200 patients met the inclusion criteria.  TAP blocks reduced 24-hour opioid consumption by 45% (MD: -20.1 mg MME,  95% CI: -24.3 to -15.9; p < 0.001) and resting pain scores by 2.1 VAS points at 12
hours (95% CI: -2.7 to -1.5; p < 0.001). Dynamic pain scores over 24 hours were also   signifcantly improved (MD: -1.8, 95% CI: -2.3 to -1.3; p < 0.001). Subgroup analysis  revealed that patients undergoing colorectal surgeries experienced the greatest  opioid-sparing effect (MD: -25.3 mg) compared to caesarean sections (MD: -18.2   mg). No signifcant differences in complications were noted (RR = 0.9, 95% CI:   0.7–1.2), with LAST occurring in only 0.04% of patients. Moderate heterogeneity (I²   = 55%) was observed across the studies.
Conclusion: TAP blocks provide a safe and effective opioid-sparing modality for  postoperative analgesia in abdominal surgeries. Their incorporation into Enhanced  Recovery After Surgery (ERAS) protocols, particularly for open abdominal   procedures, is recommended. Future research should focus on standardizing the
block technique and local anesthetic dosing to further optimize outcomes.