Clinical Evaluation of Rectus Sheath Block Versus Local Anesthetic Infiltration in Laparoscopic Inguinal Hernia Repair: A Retrospective Comparative Study

Background Laparoscopic inguinal hernia repair is frequently associated with early postoperative pain due to somatic nociceptive input from the anterior abdominal wall. Ultrasound-guided rectus sheath block (RSB) provides targeted analgesia by blocking terminal branches of the thoracoabdominal nerves within the rectus sheath. Although RSB is increasingly used in minimally invasive surgery, its comparative effectiveness against conventional local anesthetic (LA) wound infiltration in adult hernia repair remains inadequately characterized. Objectives The objective of this study is to evaluate the clinical effect of pre-incisional RSB versus postoperative LA infiltration on intraoperative opioid and dexmedetomidine requirements, as well as postoperative analgesic use, in adults undergoing laparoscopic total extraperitoneal (TEP) inguinal hernia repair. Methods This retrospective cohort study included 211 adult patients who underwent laparoscopic TEP inguinal hernia repair at Dubai Hospital between 2018 and 2025. Patients received either ultrasound-guided RSB before skin incision (n = 102) or surgeon-administered LA infiltration at the end of surgery (n = 109). Data were extracted from electronic anesthesia records and included demographics, ASA classification, body mass index (BMI), surgical duration, laterality, and intra-/postoperative analgesic consumption. Statistical analyses employed Mann-Whitney U, chi-square, and multivariable linear regression tests to adjust for surgical duration and laterality. The primary outcome was intraoperative opioid dose (morphine-equivalent mg). Secondary outcomes included intraoperative dexmedetomidine rate (µg/kg/h) and postoperative opioid and non-opioid analgesic use. Results Baseline demographic variables were comparable between groups, though operative duration and bilateral repairs were higher in the RSB group (p < 0.01). Pre-incisional RSB was associated with a significant reduction in intraoperative opioid requirement (median 3 mg vs 6 mg morphine-equivalent; p < 0.001). Regression analysis confirmed RSB as an independent predictor of lower opioid consumption (adjusted β = -3.53 mg; 95% CI -4.63 to -2.42; p < 0.0001). The median intraoperative dexmedetomidine infusion rate was lower with RSB (0.227 µg/kg/h (IQR 0.184)) versus LA (0.327 µg/kg/h (IQR 0.327); p = 0.021), but the difference lost statistical significance after adjustment (adjusted p = 0.194). Postoperative opioid requirements were minimal in both groups (median 0 mg), while RSB patients required significantly fewer non-opioid analgesic doses (paracetamol/NSAIDs, p < 0.05) and exhibited a higher incidence of complete analgesia avoidance (19.6% vs 8.3%). Conclusions Pre-incisional ultrasound-guided RSB independently reduces intraoperative opioid exposure compared with LA wound infiltration in laparoscopic TEP inguinal hernia repair. Although dexmedetomidine sparing was not significant after adjustment, the overall multimodal analgesic burden was lower in the RSB group. These findings support RSB as an effective, safe, and opioid-sparing regional technique for adult laparoscopic hernia repair.