Ultrasound-guided Retrolaminar Block Versus Intraperitoneal Block for Postoperative Analgesia of Adult Patients Undergoing Laparoscopic Cholecystectomy: Randomized, Controlled Trial

Laparoscopic cholecystectomy (LC) provides many advantages as less pain, shorter hospital stay, and earlier recovery, and it is a cost-effective procedure. Although it is a minimally invasive surgery, it causes moderate-severe pain. Pain has several sources but mostly visceral pain caused by tissue trauma during gall bladder resection is the most predominant component. Acute pain after laparoscopic cholecystectomy does not match pain after other laparoscopic surgeries because of its complexity, so proper management of pain should be procedure-specific and multimodal. Many analgesic interventions with different mechanisms have been studied for their effects on pain relief after laparoscopic cholecystectomy. Traditionally, opioids have been used to manage postoperative pain. However, an increasing awareness of opioid-related adverse events, including respiratory depression, paralytic ileus, and sedation, has led to a shift towards utilizing opioid-sparing techniques for postoperative analgesia. Ultrasound-guided retrolaminar block is a recent modified paravertebral technique for analgesia in thoracoabdominal procedures with a local anesthetic injected at the retrolaminar site. It has the advantage of being safe and easy compared with traditional thoracic epidural analgesia. It has a decreased incidence of complications such as hypotension, pleural disorder, and nerve injury.Intraperitoneal local anaesthetic administration has been used as a method for reducing postoperative pain. Intraperitoneal local anaesthetics acts on visceral nociceptors of peritoneum.Therefore, this study will be conducted to evaluate efficacy and safety of ultrasound guided retrolaminar block for postoperative analgesia in laparoscopic cholecystectomy surgery in comparison to intraperitoneal local anaesthetic administration.

Aim of the Study:

The aim of this study is to assess the quality of pain relief in patients who will undergo in laparoscopic cholecystectomy surgery receiving either retrolaminar block or peritoneal block by comparing and evaluating the differences between the two techniques. It is hypothesized that retrolaminar block will be comparable to peritoneal block as a promising effective alternative for analgesia for in laparoscopic cholecystectomy surgeries with fewer side effects.

Sample Size Calculation:

Sample size was calculated using Power Analysis and Sample Size software program (PASS) version 11.0.4 for windows (2011) with time to first analgesic request as the primary outcome. Using the results published by ahmed et al 2021 with the mean time to first analgesic request in intraperitoneal instillation group was (2.88 ± 0.33 hours). Using a two-sided two-sample unequal-variance t-test., sample size of 54 patients is needed to achieve 90% power to detect 10 % difference in time to first analgesic request. Using a two-sided hypothesis test with a significance level of 0.05. A 10% drop out is considered, so a total of 60 patients will be enrolled (30 in each group) in this study