Although laparoscopic cholecystectomy is a minimally invasive surgery, it causes moderate-severe pain. 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.

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

Methods:

The study will be conducted in Mansoura university hospital on sixty patients Who is Scheduled for laparoscopic cholecystectomy.They will be randomly assigned to two equal groups (retrolaminar group and peritoneal group) according to computer-generated table of random numbers using the permuted block randomization method. The group allocation will be concealed in sequentially numbered, sealed opaque envelopes which will be opened only after obtaining the written informed consent. Patient demographic data including age, sex and body weight will be recorded. A written informed consent will be obtained from all study subjects after ensuring confidentiality. The study protocol will be explained along with VAS to all patients after enrollment into the study. In both groups, the block will be under strict aseptic conditions after patient intubation and before skin incision.

Statistical Methods:

The collected data will be coded, processed, and analyzed using SPSS(Statistical Package for the Social Sciences) program (version 22) for Windows. Normality of numerical data distribution will be tested by Shapiro-Wilk test. Continuous data of normal distribution will be presented as mean ± SD (Standard deviation)and compared with the unpaired student's t test. Non-normally distributed data will be presented as median (range) and compared with the Mann-Whitney U test. Repeated measures ANOVA will be used for comparisons within the same group. Categorical data will be presented as number (percentage) and compared with the Chi-square test. All data will be considered statistically significant if P value is ≤ 0.05.Conditions

Inclusion Criteria:

• American Society of Anesthesiology (ASA) 1 or 2 patients.
• Scheduled for laparoscopic cholecystectomy

Exclusion Criteria:

• Patient's refusal.
• Altered mental status or un-cooperative patients.
• History of known sensitivity to the used anesthetics.
• Bleeding or coagulation diathesis.
• Infection or redness at the injection site.
• Significant cardiac dysfunction, hepatic, or renal impairment

The study subjects and the resident assessing the outcomes will be blinded to the study group. A single investigator will assess the patients for eligibility, obtain written informed consent, open the sealed opaque envelopes containing group allocation, perform the block, and administer bupivacaine solution.