Evaluation of Ultrasound-guided Erector Spinae Plane Block for Postoperative Analgesia in Laparoscopic Sleeve Gastrectomy: A Prospective, Randomized, Controlled Clinical Trial

Research Proposal and significance Postoperative analgesia should include strategies to reduce side effects. Intravenous analgesics are generally considered to be adequate for pain management in upper GI laparoscopic surgeries. However opioids can lead to nausea, vomiting and itching while NSAIDs affect the gastric, hepatic and renal systems and wound healing. Reducing opioid requirements during the perioperative period is among the current goals of enhanced recovery programs. The objective is to reduce all potential opioid-related side-effects. Therefore, multimodal analgesics including regional blocks decrease the use of other analgesics and therefore decrease side effects.

Objective The aim of this study is to evaluate the effect of Erector spinae block (ESPB) on postoperative pain in upper GI laparoscopy surgeries, which leads to both visceral and somatic pain.

Research review In this study, the surgeries included in upper GI laparoscopic surgeries are laparoscopic cholecystectomy, laparoscopic gastrectomy, laparoscopic umblical or epigastric hernia repair.

n upper GI laparoscopy surgeries, postoperative pain is caused by two reasons; one is somatic pain from the trocar entry incisions and additionally peritoneal distention and diaphragm irritation due to high intra-abdominal pressure and CO2 insufflations lead to visceral pain as well. Therefore, any analgesic protocol for these surgeries must be effective on both sources of pain.

Regional block techniques studied and considered part of multimodal anesthesia include transversus abdominis plane block (TAP), oblique subcostal transversus abdominis plane block (OSTAP or STAP) and paravertebral block. Apart from paravertebral block, these techniques only effect somatic pain and can therefore be inadequate in some cases. Ultrasound Guided paravertebral block is an advanced regional anesthesia technique. When considering that the pleura forms one boundary of the paravertebral space, ESPB can be considered an easier technique to perform. It is also safer because the needle remains behind the transverse process. However, non-inferiority studies comparing ESPB and paravertebral block are required. Erector Spinae Plane Block (ESPB) - first recently described for the treatment of thoracic neuropathic pain, is a peri-paravertebral regional anesthesia technique that has since been reported as an effective technique for prevention of postoperative pain in various surgeries. In ESPB, local anesthetic is reported to be administered in to the interfascial plane between the transverse process of the vertebra and the erector spinae muscles, spreading to multiple paravertebral spaces. Case reports have reported that ESPB effects both the ventral and dorsal rami and leading to blockage of both visceral and somatic pain. Anatomical dissection indicates that the likely mechanism of action is diffusion of local anaesthetic anteriorly through the connective tissues and ligaments spanning the adjacent transverse processes and into the vicinity of the spinal nerve roots. This is consistent with other reports of successful analgesia following injection into a similar tissue plane in the thorax.