Efficacy of Adding Magnesium Sulfate to Combined Pecto-Intercostal & Serratus Anterior Planes Block on Post-operative Analgesia in Patients Undergoing Modified Radical Mastectomy: A Prospective, Randomized Controlled Clinical Trial

Modified radical mastectomy, a common surgical intervention for breast cancer therapy, and is often associated with extensive postoperative pain. Effective regional anesthesia techniques are important modalities to manage this pain and reduce total opioid consumption in the early postoperative phase. A few interfacial nerve block methods (for example, pectoral nerve blocks I and II and erector spinae plane block) are also utilized in some other procedures to reduce the postoperative pain. However, these methods require particular patient positioning.

A new, minimally-invasive technique called pecto-intercostal fascial plane block (PIFB) was firstly used by De la Torre in patients who had undergone breast surgery. The Pecto-Intercostal Fascial Block (PIFB) and the Serratus Anterior Plane Block (SAPB) have appeared as promising techniques for providing pain relief in breast surgeries. PIFB targets the anterior cutaneous branches of the intercostal nerves, while SAPB focuses on the lateral cutaneous branches, each offering distinct anatomical coverage. Some specific benefits have been reported when using PIFB such as less invasiveness, proximity to the incision line, and postoperative administration with no specific patient positioning.

Recent studies have examined the efficacy of adding adjuvants to local anesthetics. Magnesium sulfate, known for its NMDA receptor antagonism and calcium channel blocking properties, has been investigated for its potency to prolong pain relief and improve analgesic control when used as an adjuvant in peripheral blocks. Evaluating the efficacy of magnesium sulfate in these fascial plane blocks may lead to the establishment of an improved standard of care in postoperative pain management.

While both PIFB and SAPB are considered safe and relatively easy to perform using ultrasound, comparative data regarding their efficacy, especially with magnesium sulfate as an adjuvant, remains limited. The outcomes of this study may help define a more effective and standardized analgesic approach for patients undergoing modified radical mastectomy. Furthermore, minimizing systemic opioid requirements is especially gaining interest considering current efforts to reduce opioid-related side effects and dependence in surgical patients.

Here, in our study, we intend to compare the analgesic efficacy of magnesium sulfate as an adjuvant to local anesthetics added to the Pecto-Intercostal Fascial Block (PIFB) vs the Serratus Anterior Plane Block (SAPB) in patients undergoing modified radical mastectomy.