Magnesium Sulfate With Standard Combined Costoclavicular-Suprascapular Block for Pain Relief After Shoulder Arthroscopy.

This randomized clinical trial will evaluate the analgesic effect of adding magnesium sulfate to a combined costoclavicular and suprascapular nerve block in patients undergoing shoulder arthroscopy. Shoulder arthroscopy can be associated with significant postoperative pain, and effective regional anesthesia may improve postoperative analgesia and reduce the need for rescue analgesics.

Eligible patients undergoing shoulder arthroscopy will be randomly assigned to receive either a combined costoclavicular and suprascapular nerve block with magnesium sulfate as an adjuvant or the same nerve block without magnesium sulfate. Standardized anesthetic and postoperative analgesic protocols will be applied to both groups.

The primary outcome will be the time to first rescue analgesia after surgery. Secondary outcomes will include postoperative pain scores and other relevant analgesic and safety outcomes during the postoperative observation period.

The study aims to determine whether the addition of magnesium sulfate can prolong the duration of analgesia and improve postoperative pain management following shoulder arthroscopy.

• Bupivacaine (Drug): "Bupivacaine 0.5% will be used as the local anesthetic for ultrasound-guided costoclavicular and suprascapular nerve blocks. A total of 25 mg (5 mL) will be administered for the costoclavicular nerve block and 50 mg (10 mL) for the suprascapular nerve block, for a total dose of 75 mg per participant."
• Magnesium sulfate (MgSO4) (Drug): "Magnesium sulfate 150 mg (1.5 mL) will be used as an adjuvant to bupivacaine in each ultrasound-guided nerve block. A total of 300 mg (3 mL) of magnesium sulfate will be administered per participant, with 150 mg added to the costoclavicular nerve block and 150 mg added to the suprascapular nerve block."
• Normal Saline (NS) (Drug): "Normal saline (0.9% sodium chloride) will be used as the control adjuvant, with 1.5 mL added to the local anesthetic solution for the costoclavicular nerve block and 1.5 mL added to the local anesthetic solution for the suprascapular nerve block, for a total volume of 3 mL per participant."
• Costoclavicular Nerve Block (Procedure): "A single-shot ultrasound-guided costoclavicular nerve block will be performed using 5 mL of 0.5% bupivacaine (25 mg), with either 1.5 mL of magnesium sulfate (150 mg) or 1.5 mL of 0.9% normal saline, according to the assigned study group."
• suprascapular nerve block (Procedure): "A single-shot ultrasound-guided suprascapular nerve block will be performed using 10 mL of 0.5% bupivacaine (50 mg), with either 1.5 mL of magnesium sulfate (150 mg) or 1.5 mL of 0.9% normal saline, according to the assigned study group."

Primary outcomes

• Time to first rescue analgesia after discharge from PACU. [From discharge from PACU until 24 hours postoperatively.]: Time to first rescue analgesia will be measured from the time of discharge from the Post-Anesthesia Care Unit (PACU) until the first administration of rescue analgesic medication for 24 hour due to postoperative pain. Numeric Rating Scale (NRS): Pain intensity was assessed using the 11-point Numeric Rating Scale (NRS), in which 0 = no pain and 10 = the worst pain imaginable.

Secondary outcomes

• Postoperative Pain Score Using the Numeric Rating Scale [At predetermined time points after surgery at ( 2h,6h,12h,18h,24h) during the first 24 hours postoperatively.]: Postoperative pain intensity will be assessed from the end of surgery for 24 hours postoperatively using the Numeric Rating Scale (NRS), ranging from 0 to 10, where 0 indicates no pain and 10 indicates the worst pain imaginable. Higher scores indicate worse pain.
• Total Postoperative analgesic Consumption [First 24 hours postoperatively (one day).]: The total amount of rescue analgesia consumed during the first 24 hours after surgery will be recorded.
• Duration of sensory block [From completion of the nerve block until the first administration of rescue analgesia24 hours postoperatively.]: Duration of sensory block will be assessed as the time interval from completion of the nerve block to the first administration of rescue analgesia 24 hours postoperatively.
• Heart rate [From baseline before the nerve block until the end of surgery.]: Heart rate will be recorded at predefined perioperative time points to assess hemodynamic stability from baseline before surgery until end of surgery.
• Systolic blood pressure (SBP) [From baseline before anesthesia induction until 24 hours postoperatively.]: Systolic blood pressure will be recorded at baseline and at predefined intraoperative every 5 minutes and postoperative time points at (2h, 6h,12h,24h).
• Diastolic blood pressure (DBP) [From baseline before anesthesia induction until 24 hours postoperatively.]: Diastolic blood pressure will be recorded at baseline and at predefined intraoperative every 5 minutes and postoperative time points at (2h, 6h,12h,24h).
• Mean Arterial Pressure [From baseline before anesthesia induction until 24 hours postoperatively.]: Mean Arterial Pressure will be recorded at baseline and at predefined intraoperative every 5 minutes and postoperative time points at (2h, 6h,12h,24h).
• Incidence of Block-Related Adverse Events [From performance of the nerve blocks until 24 hours postoperatively.]: The incidence of adverse events related to the regional anesthesia technique, including symptoms or complications associated with the nerve blocks, will be recorded.

Sex: All, ages: 18 Years to 50 Years

Inclusion Criteria:

* Age between 18-50 years
* American Society of Anesthesiologists (ASA) physical status I-II.
* Scheduled for elective outpatient shoulder arthroscopy.
* Ability to understand the study protocol and use the NRS scale.

Exclusion Criteria:

* Refusal to participate.
* Known allergy or hypersensitivity to local anesthetics or magnesium sulphate.
* Coagulopathy or anticoagulant therapy contraindicating regional anesthesia.
* Local infection at the block site.
* Pre-existing peripheral neuropathy or neurologic deficit involving the operative limb.
* Body mass index (BMI) > 40 kg/m² (if desired for technical standardization).
* Chronic opioid use or chronic pain syndrome affecting pain assessment.
* Pregnancy or lactation.
* Inability to communicate or complete postoperative assessments.

• Pirotesak S, Fallah N, Alruqaie R, Rodelo K, Asenjo JF, Aliste J. Costoclavicular brachial plexus block for shoulder surgery: a narrative review. Korean J Anesthesiol. 2025 Dec;78(6):513-523. doi: 10.4097/kja.25422. Epub 2025 Aug 4. PMID 40755089
• Soleimanpour H, Imani F, Dolati S, Soleimanpour M, Shahsavarinia K. Management of pain using magnesium sulphate: a narrative review. Postgrad Med. 2022 Apr;134(3):260-266. doi: 10.1080/00325481.2022.2035092. Epub 2022 Feb 7. PMID 35086408
• Jo Y, Oh C, Lee WY, Chung HJ, Park J, Kim YH, Ko Y, Chung W, Hong B. Randomised comparison between superior trunk and costoclavicular blocks for arthroscopic shoulder surgery: A noninferiority study. Eur J Anaesthesiol. 2022 Oct 1;39(10):810-817. doi: 10.1097/EJA.0000000000001735. Epub 2022 Aug 17. PMID 35975762
• Nam YS, Jeong JJ, Han SH, Park SE, Lee SM, Kwon MJ, Ji JH, Kim KS. An anatomic and clinical study of the suprascapular and axillary nerve blocks for shoulder arthroscopy. J Shoulder Elbow Surg. 2011 Oct;20(7):1061-8. doi: 10.1016/j.jse.2011.04.022. Epub 2011 Aug 11. PMID 21839653
• Galluccio F, Fajardo Perez M, Yamak Altinpulluk E, Hou JD, Lin JA. Evaluation of Interfascial Plane and Pericapsular Nerve Blocks to the Shoulder Joint: A Preliminary Analysis of Shoulder Anterior Capsular Block. Pain Ther. 2021 Dec;10(2):1741-1754. doi: 10.1007/s40122-021-00326-0. Epub 2021 Oct 20. PMID 34669181
• Kay J, Memon M, Hu T, Simunovic N, Duong A, Paul J, Athwal G, Ayeni OR. Suprascapular Nerve Blockade for Postoperative Pain Control After Arthroscopic Shoulder Surgery: A Systematic Review and Meta-analysis. Orthop J Sports Med. 2018 Dec 28;6(12):2325967118815859. doi: 10.1177/2325967118815859. eCollection 2018 Dec. PMID 30627589

• Mohamed Mohamed Abdel Latif, professor, Principal investigator, Assiut University, Faculty of Medicine
• Eman Ahmed Ismail, professor, Study director, Assiut University, Faculty of Medicine
• Mohamed Talaat Mohamed, Lecturer, Study director, Assiut University, Faculty of Medicine
• Ahmed Shaban Abd Elbadea Khalifa, Assistant lecturer, Study chair, Assiut University, Faculty of Medicine