Obesity is ranked as the 5th cause of preventable death and is associated with certain diseases, e.g., type 2 diabetes mellitus, hypertension, ischemic heart disease, hyperlipidemia, and sleep apnea. Egypt has the world's 18th highest obesity prevalence, according to the World Health Organization (WHO). Bariatric surgery is the most effective treatment for weight loss, reducing obesity-related comorbidities and mortality. This surgery has been shown to improve quality of life. Bariatric surgery is now universally performed laparoscopically and is the most performed elective surgery in patients with morbid obesity. Laparoscopic sleeve gastrectomy (LSG) has been shown to be related to lower complication rates, shorter hospital stays, and earlier re-engagement in normal activities than open procedures. However, postoperative pain is common. Pain often originates from port sites in the abdominal wall. As LSG requires removal of the relatively large resected gastric segment, this often requires enlargement of the trocar site and the fascial incision, which adds to the pain. Postoperative pain may be significant and has a negative impact on recovery, respiration, hemodynamics, mentation, ambulation, bowel function, and length of hospital stay. Also, opioid analgesia in obese patients is associated with serious adverse effects such as hypopnoea, hypoxaemia, drowsiness, ileus, vomiting, delayed ambulation, and mortality. These complications are compounded by pre-existing obstructive sleep apnea (OSA), cardiorespiratory insufficiency, psychiatric disorders, and chronic opioid use, which may be present in obese patients. Although epidural anesthesia is effective in pain control, positioning is extremely difficult in obese patients. Some regional anesthesia techniques such as transverse abdominis plane (TAP) block, quadratus lumborum (QL) block, and erector spinae plane (ESP) block may be used as a part of a multimodal analgesic regimen to reduce opioid consumption
. However, technical challenges such as difficulty in identifying the structures and limitations in needle movement may be experienced due to the deep anatomical location of structures when performing these blocks in patients with obesity.
Intertransverse process block (ITPB) is a paraspinal thoracic nerve block technique where the local anesthetic (LA) is injected into the thoracic "intertransverse tissue complex", behind the superior costotransverse ligament (SCTL). The retro superior costotransverse ligament space (retro-SCTL space) block is a novel ITPB, targeting the fat-filled space in the retro-SCTL space. ITPB may be technically simpler and safer to avoid pleural puncture than a thoracic paravertebral block (TPVB) since it does not require direct needle access to the thoracic paravertebral space.
External oblique intercostal plane (EOI) block, a nerve block , has an efficacy range of T6-10. EOI block is one of the novel interfascial plane blocks. EOI block can be performed as part of multimodal analgesia for upper abdominal surgeries. In addition, easy visualization of the application area with ultrasound guidance is an advantage for obese patients. While both retro-SCTL and EOI blocks are emerging techniques, a direct comparison of their analgesic efficacy and opioid-sparing effects in the context of LSG has not yet been performed. This study aims to directly address this gap.
