Adding Magnesium Sulphate to Combined Pectointercostal Plane and Erector Spinae Plane Blocks for Acute and Chronic Post-Mastectomy Pain

Efficacy of Adding Magnesium Sulphate to Combined Pectointercostal Plane Block and Erector Spinae Plane Block for Acute and Chronic Post-Mastectomy Pain After Modified Radical Mastectomy. A Controlled Clinical Trial

Given the burden of chronic postmastectomy pain and the need for effective, opioid-sparing analgesia, the propose of the randomized controlled trial is to evaluate the safety and efficacy of adding magnesium sulphate to the combination of PIP block and ESPB in patients undergoing modified radical mastectomy for reducing acute and chronic post mastectomy pain

Study Overview

• Status: Not yet recruiting
• Conditions: Post-mastectomy Pain Syndrome
• Intervention / Treatment: Procedure: Pectointercostal Plane Block (PIPB); Procedure: Erector Spinae Plane Block (ESPB); Drug: Magnesium sulfate

Detailed Description

Breast cancer remains one of the most common malignancies worldwide, and modified radical mastectomy (MRM) continues to be a mainstay surgical treatment in many cases. However, postoperative pain after MRM can be significant, both in the acute period and long-term, contributing to persistent pain syndromes, impaired recovery, and reduced quality of life. Regional anesthesia techniques such as the pectointercostal plane (PIPB) block and erector spinae plane block (ESPB) have gained wide acceptance as effective approaches to reduce perioperative analgesic requirements, improve pain control, and potentially mitigate chronic post-surgical pain. Magnesium sulphate (MgSO4 ) is increasingly studied as an adjuvant in regional anesthesia, owing to its NMDA-receptor antagonism, calcium channel modulation, and possible anti-inflammatory effects. Meta-analyses in peripheral nerve blocks, such as supraclavicular brachial plexus block, have demonstrated that adding MgSO4 prolongs sensory and motor blockade, delays the need for rescue analgesia, and is generally well tolerated. Moreover, in abdominal surgery, MgSO4 added to bupivacaine in a transversus abdominis plane (TAP) block significantly reduced postoperative pain scores and extended analgesia duration. Erector spinae plane block is particularly attractive in mastectomy because it provides extensive dorsal and lateral thoracic analgesia. Beyond ESPB and Pectointercostal Plane Block, other interfascial plane blocks in breast surgery have also shown benefit with magnesium. Such consistent results across different block techniques support the hypothesis that magnesium enhances regional anesthesia outcomes in breast surgery.

Despite this promising data, there remain gap. No study has yet, concurrently evaluated magnesium as an adjuvant to both PIP block and ESPB in the same patient population, nor assessed its effects on both acute postoperative pain and the development of chronic postoperative pain.

So, the aim of this randomized controlled trial is to evaluate the safety and efficacy of adding magnesium sulphate to the combination of PIP block and ESPB for reducing acute and chronic post mastectomy pain in patients undergoing modified radical mastectomy.

A randomized controlled double-blinded study will be conducted in South Egypt Cancer Institute, Assiut University, after approval from the Institutional Ethics Committee.

Primary outcome:

Time to first rescue analgesia.

Secondary outcomes:

Total opioid consumption (morphine equivalent) in the first 24 hours postoperatively.

Postoperative pain scores (VAS) at rest and movement. Incidence of postoperative nausea and vomiting. Block-related complications. Incidence and severity of chronic post mastectomy pain.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: mohamed fa abd elhamed, lecturer; Phone Number: 02 01015249890; Email: m.farghaly.na@gmail.com
• Study Contact Backup: Name: bahaa ga saad, lecturer; Phone Number: 01003644592

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Female patients aged ≥18 years.
• American Society of Anesthesiologists (ASA) class I-III.
• Scheduled for unilateral modified radical mastectomy.

Exclusion Criteria:

• Known allergy to local anesthetics or magnesium.
• Coagulopathy or anticoagulant therapy.
• Local infection at injection site.
• Body mass index (BMI) ≥ 40 kg/m2.
• Chronic opioid use or chronic pain disorders.
• Neurological or psychiatric disorders affect pain perception.
• Severe hepatic or renal impairment.
• Pregnancy.
• Lactation.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Group M (Magnesium Group); Patients will receive the combined PIP and ESP blocks using bupivacaine + magnesium sulphate.; 20 mL of 0.25% bupivacaine + 150 mg magnesium sulphate diluted to5 ml (in each block).; 150 mg with each block (total magnesium dose = 300 mg).	Procedure: Pectointercostal Plane Block (PIPB); A high-frequency linear ultrasound probe will be placed at the level of the 2nd-3rd rib, medial to the pectoralis major muscle. The pectointercostal fascial plane located between the pectoralis major muscle and the external/internal intercostal muscles will be identified. Under in plane ultrasound guidance, the needle will be advanced into this plane, and the study drug will be administered. All patients will receive 20 mL of 0.25% bupivacaine; however, patients in Group M will additionally receive magnesium sulphate 150 mg diluted to 5 mL, which will be injected into the same plane.; Other Names: (PIPB); Procedure: Erector Spinae Plane Block (ESPB); For this block, the patient will be positioned laterally. The ultrasound probe will be placed at the T3-T5 vertebral level to visualize the transverse process. An in- plane technique will be used to advance the needle into the deep fascial plane beneath the erector spinae muscle. Once the correct position is confirmed, 20 mL of 0.25% bupivacaine will be injected, with Group M patients receiving an additional 150 mg of magnesium sulphate diluted to 5 mL. The total magnesium dose administered in Group M will be 300 mg. Negative aspiration will be performed prior to each injection to avoid intravascular administration.; Other Names: (ESPB): Drug: Magnesium sulfate; All patients will receive 20 mL of 0.25% bupivacaine; however, patients in Group M will additionally receive magnesium sulphate 150 mg diluted to 5 mL, which will be injected into the same plane. The total magnesium dose administered in Group M will be 300 mg
Sham Comparator: Group C (Control Group); Patients will receive the combined PIP and ESP blocks using bupivacaine only (20 ml of 0.25% bupivacaine)	Procedure: Pectointercostal Plane Block (PIPB); A high-frequency linear ultrasound probe will be placed at the level of the 2nd-3rd rib, medial to the pectoralis major muscle. The pectointercostal fascial plane located between the pectoralis major muscle and the external/internal intercostal muscles will be identified. Under in plane ultrasound guidance, the needle will be advanced into this plane, and the study drug will be administered. All patients will receive 20 mL of 0.25% bupivacaine; however, patients in Group M will additionally receive magnesium sulphate 150 mg diluted to 5 mL, which will be injected into the same plane.; Other Names: (PIPB); Procedure: Erector Spinae Plane Block (ESPB); For this block, the patient will be positioned laterally. The ultrasound probe will be placed at the T3-T5 vertebral level to visualize the transverse process. An in- plane technique will be used to advance the needle into the deep fascial plane beneath the erector spinae muscle. Once the correct position is confirmed, 20 mL of 0.25% bupivacaine will be injected, with Group M patients receiving an additional 150 mg of magnesium sulphate diluted to 5 mL. The total magnesium dose administered in Group M will be 300 mg. Negative aspiration will be performed prior to each injection to avoid intravascular administration.; Other Names: (ESPB):

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to first rescue analgesia.	Rescue analgesia of morphine will be given as 3 mg bolus if the VAS > 3 to be repeated after 30 min if pain persists until the VAS < 4.	24 hours postoperatively

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total opioid consumption .	Total opioid consumption (morphine equivalent) in the first 24 hours postoperatively	24 hours postoperatively
Postoperative pain scores (VAS)	Postoperative pain scores (VAS) at rest and movement where 0= no pain, 10= worst imaginable pain	24 hours postoperatively

Collaborators and Investigators

• Sponsor: South Egypt Cancer Institute
• Collaborators: Assiut University

Study record dates

Study Major Dates

• Study Start (Estimated): February 15, 2026
• Primary Completion (Estimated): November 1, 2026
• Study Completion (Estimated): February 15, 2027

Study Registration Dates

• First Submitted: February 8, 2026
• First Submitted That Met QC Criteria: February 22, 2026
• First Posted (Actual): February 27, 2026

Study Record Updates

• Last Update Posted (Actual): February 27, 2026
• Last Update Submitted That Met QC Criteria: February 22, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Sulfur Compounds; Inorganic Chemicals; Sulfur Acids; Sulfates; Sulfuric Acids; Magnesium Compounds; Magnesium Sulfate; PipB protein, Salmonella enterica
• Other Study ID Numbers: 18-2026-811; 811 (Registry Identifier: IRB)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No