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 shoulder block versus PENG block comparing and evaluating the differences between the two techniques.It is hypothesized that PENG block will be comparable to shoulder 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.

Effective analgesia in arthroscopic shoulder surgery is a major concern and is essential for all aspects of the patient's recovery. Multimodal pain management is recommended for early postoperative pain control. 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. Shoulder block which is combination of suprascapular nerve block and axillary nerve block has been recently proposed as an alternative anesthetic and postoperative analgesic modality in this patient population. These two nerve blocks cause the loss of the sensory innervation of the shoulder. Shoulder block is advantageous to the interscalene brachial plexus block since it does not lead to respiratory dysfunction due to phrenic nerve palsy or other serious complications.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 shoulder block with PENG block for postoperative analgesia in patients undergoing arthroscopic shoulder surgeries.

The aim of this study:

assess the quality of pain relief in patients who will undergo arthroscopic shoulder surgeries receiving either shoulder 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 time to first analgesic request as the primary outcome. Using the results published by Pani et al 2019 with the mean time to first analgesic request in shoulder block group was (5.9 ± 1.2 hours) Using a two-sided two-sample unequal-variance t-test, sample size of 40 patients is needed to achieve 90% power to detect 20 % 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 46 patients will be enrolled (23 in each group) in this study.

Methods:

The study will be conducted in Mansoura university hospital on Forty six patients who will be scheduled for arthroscopic shoulder surgery under general anesthesia. They will be randomly assigned to two equal groups (PENG group and shoulder block 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 shoulder block procedures will be performed in the preoperative regional room under strict aseptic conditions using 30 ml 0.25% bupivacaine.

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.

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