Transversus abdominis plane (TAP) block versus standard analgesia for postoperative pain following open upper abdominal surgery through a midline incision: a protocol for a prospective randomized controlled trial

AIMS: To determine whether bilateral ultrasound-guided subcostal transversus abdominis plane (TAP) block, added to standardized non-opioid multimodal analgesia, reduces early pain after open upper midline laparotomy. PATIENTS AND METHODS: In this single-center, parallel-group randomized controlled superiority trial, 108 adults undergoing elective open upper abdominal surgery through a midline incision will be randomized 1:1 (stratified by procedure category) to TAP block (bupivacaine 0.25%, 30 mL per side, maximum 2.5 mg/kg) plus multimodal analgesia or multimodal analgesia alone. Outcome assessors and the statistician will be blinded; no sham block is used. The primary outcome is pain at rest on a 100-mm visual analog scale (VAS), averaged over 6, 12 and 24 h after surgery. Secondary outcomes include movement-evoked pain, Quality of Recovery-15 (QoR-15), consumption of each rescue analgesic, postoperative nausea and vomiting (PONV), time to ambulation, time to first flatus and adverse events (actively monitored until 48 h after surgery or hospital discharge, whichever is later). PLANNED ANALYSIS: The primary effect will be estimated by intention-to-treat using a mixed model for repeated measures, as the equally weighted mean between-group difference with 95% confidence interval. CONCLUSION: This trial will quantify the incremental benefit of subcostal TAP block in a defined surgical population. CLINICAL TRIAL REGISTRATION: Pan African Clinical Trials Registry (www.pactr.org) identifier is PACTR202608546707144. TRIAL REGISTRATION: Pan African Clinical Trials Registry (PACTR; www.pactr.org), PACTR202608546707144, registered on 18 August 2026.