Rectus Sheath Block Versus Transversus Abdominis Plane Block for Analgesia in Laparoscopic Bariatric Surgery

Comparison of Rectus Sheath Block and Transversus Abdominis Plane Block for Analgesia in Laparoscopic Bariatric Surgery: A Randomized Controlled Trial

This randomized controlled trial aims to compare the analgesic efficacy of rectus sheath block (RSB) and transversus abdominis plane block (TAPB) in patients undergoing laparoscopic bariatric surgery. Both techniques are regional anesthesia methods used as part of multimodal analgesia to reduce postoperative pain and opioid requirements.

Eligible participants will be randomly assigned to receive either a RSB or a TAPB after general anesthesia. Postoperative pain scores, opioid consumption, recovery outcomes, area of sensory loss, time to first rescue analgesia, and block-related adverse events will be assessed and compared between the two groups.

This study will help determine which regional anesthesia technique provides more effective postoperative analgesia for laparoscopic bariatric surgery

Laparoscopic bariatric surgery provides sustained weight loss for patients with obesity and is associated with improved metabolic outcomes and increased life expectancy. Despite its minimally invasive approach, laparoscopic bariatric surgery is often associated with moderate-to-severe postoperative pain, which may require significant opioid use. Postoperative opioid administration may increase the risk of opioid-related adverse effects, including opioid-induced ventilatory depression and postoperative nausea and vomiting. These concerns are particularly important in patients with obesity, who may have an increased risk of obstructive sleep apnea and opioid-related respiratory complications.

Enhanced Recovery After Surgery principles recommend opioid-sparing strategies, including regional anesthesia and local anesthetic techniques, as part of multimodal analgesia for bariatric surgery. Several regional analgesic techniques have been used for laparoscopic bariatric surgery, including local infiltration analgesia, transversus abdominis plane block, rectus sheath block, and other fascial plane blocks.

Transversus abdominis plane block is commonly used for abdominal surgery and provides somatic analgesia to the anterolateral abdominal wall. However, its analgesic efficacy in laparoscopic bariatric surgery remains variable, partly due to differences in block technique, injection site, local anesthetic regimen, and technical challenges in patients with obesity. Excessive subcutaneous tissue may make identification of the target fascial plane more difficult and may increase the risk of inaccurate needle placement or incomplete sensory blockade.

Rectus sheath block is another regional anesthesia technique used for abdominal surgery. It involves the injection of local anesthetic between the rectus abdominis muscle and the posterior rectus sheath, providing analgesia to the anterior abdominal wall, particularly around the midline and periumbilical region. Rectus sheath block may be technically easier to perform than transversus abdominis plane block in patients with obesity because of its more superficial needle trajectory. Previous studies suggest that rectus sheath block may reduce postoperative pain and opioid consumption compared with systemic analgesia alone or local infiltration analgesia.

Although both rectus sheath block and transversus abdominis plane block may improve postoperative analgesia after laparoscopic bariatric surgery, their relative efficacy remains unclear. No previous study has directly compared these two techniques for postoperative analgesia in this surgical population.

This randomized controlled trial will compare the analgesic efficacy and opioid-sparing effects of ultrasound-guided rectus sheath block (RSB) and ultrasound-guided transversus abdominis plane block (TAPB) in patients undergoing laparoscopic bariatric surgery. Eligible participants will be randomly assigned to receive either RSB or TAPB as part of perioperative multimodal analgesia.

The study will assess postoperative pain intensity, opioid consumption, quality of recovery, rescue analgesic requirements, and block-related adverse events. The primary analysis will evaluate whether one technique provides superior analgesia. If superiority is not demonstrated, equivalence will be assessed. The findings may help guide the selection of regional anesthesia techniques for postoperative analgesia in patients undergoing laparoscopic bariatric surgery.

Inclusion Criteria:

• Patients aged 20-60 years old
• Scheduled for elective LBS including laparoscopic sleeve gastrectomy, proximal jejunal bypass, and Roux-en-Y gastric bypass
• American Society of Anesthesia (ASA) physical status III
• Have ability to communicate and understand the study and accept to participate in the study

Exclusion Criteria:

• Patients who have following underlying disease: severe hepatic impairment [diagnosed of cirrhosis (Child-Pugh C)], coagulopathy (diagnosed of disease associated with abnormal coagulation), pre-existing neurological deficits, chronic pain (diagnosed of chronic pain disease or current use regular analgesic drugs), or any drug addiction.
• Known allergy to bupivacaine or weighing less than 60 kg, as the planned doses of bupivacaine may exceed safe maximum limits.
• Patient with previous foregut surgery including esophageal, gastric, liver and pancreases resection.