Effective analgesia in arthroscopic shoulder surgery is a major concern and is essential for all aspects of the patient's recovery. The aim of this study is to assess the quality of pain relief in patients who will undergo arthroscopic shoulder surgeries receiving either serratus anterior plane block versus PENG block comparing and evaluating the differences between the two techniques.It is hypothesized that PENG block will be comparable to serratus anterior plane block as a promising effective alternative for analgesia for arthroscopic shoulder surgeries with fewer side effects. It is suggested that the PENG block can be safely applied for analgesia.

Multimodal pain management is recommended for early postoperative pain control in arthroscopic shoulder surgery. Regional anesthesia is preferred in shoulder surgery as an effective means of providing anesthesia and postoperative analgesia.Commonly used techniques for shoulder surgery include interscalene brachial plexus (ISB) blocks, continuous ISB (CISB) blocks, suprascapular nerve blocks (SSB), supraclavicular nerve blocks (SCB), local infiltration (LI), and ISB with adjuvants. Interscalene brachial plexus (ISB) block is considered the analgesic technique of choice for shoulder surgery.Relevant studies have found that ultrasound-guided serratus anterior plane block(SAPB) can achieve good anterior lateral chest wall analgesia by injecting local anesthetics into the anterior saw muscle and blocking the lateral cutaneous branch of intercostal nerve which has a significant analgesic effect.The pericapsular nerve group (PENG) block may be safely applied for both partial anesthesia and analgesia in selected shoulder surgery cases. It did not cause motor block or pulmonary complications, nor result in muscle laxity, blocking only the shoulder and the upper third of the humerus. PENG block has been studied extensively in hip surgeries but its place in shoulder surgeries is not yet clear. Therefore, this study will be conducted to compare efficacy of ultrasound guided serratus anterior plane block with PENG block for postoperative analgesia in patients undergoing arthroscopic shoulder surgeries.

The aim of this study:

The aim of this study is to assess the quality of pain relief in patients who will undergo arthroscopic shoulder surgeries receiving either serratus anterior plane block versus PENG block comparing and evaluating the differences between the two techniques.

Sample Size Calculation:

Sample size was calculated using Power Analysis and Sample Size software program (PASS) version 11.0.4 for windows (2011) with mean VAS score at 6 h postoperative as the primary outcome. Using the results published by Zhu H, et al 2022 with mean VAS score at 6 h postoperative in serratus group was (1.85 ± 0.59 ) Using a two-sided two-sample unequal-variance t-test., sample size of 44 patients is needed to achieve 90% power to detect 30 % difference in at 6 h postoperative. Using a two-sided hypothesis test with a significance level of 0.05. A10% drop out is considered, so a total of 50 patients will be enrolled (25 in each group) in this study

Methods:

The study will be conducted in Mansoura university hospital on Fifty patients who will be scheduled for arthroscopic shoulder surgery under general anesthesia. They will be randomly assigned to two equal groups (PENG group and SAPB 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. A written informed consent will be obtained from all study subjects after ensuring confidentiality. The study protocol will be explained to all patients after enrollment into the study along with VAS after enrollment into the study. Basic demographic characters including age, sex, and weight will be recorded. In both groups, The PENG and SAPB procedures will be performed in the preoperative room under strict aseptic conditions using 30 ml 0.25% bupivacaine.

Statistical Methods:

The collected data will be coded, processed, and analyzed using 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 ± standard deviation and compared with the unpaired student's t test. Nonnormally 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.

Inclusion Criteria:

• American Society of Anesthesiology (ASA) 1 or 2 patients.
• Scheduled for elective unilateral shoulder arthroscopy.

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.