Comparison Between Erector Spinae Plane Block versus Serratus Anterior Plane Block Regarding Analgesia and Stress Response After Modified Radical Mastectomy: Randomized Controlled Trial.

Background: Modified radical mastectomy (MRM) is the primary surgical treatment for breast cancer, yet it leads to significant postoperative pain. Objectives: This randomized controlled trial evaluates the effects of an erector spinae plane block (ESPB) versus a serratus anterior plane block (SAPB) on post-MRM pain management and stress response reduction. Methods: Sixty individuals scheduled for unilateral MRM under general anesthesia from October 2021 to October 2022 were divided into three groups. Group A comprised 20 patients who received ultrasound-guided ESPB (20 mL of 0.25% bupivacaine). Group B included 20 patients who received ultrasound-guided SAPB (20 mL of 0.25% bupivacaine). Group C was treated with intravenous morphine based on pain scores. Anesthesia was induced using 2 μg/kg of fentanyl and 2 - 3 mg/kg of propofol. The study compared the three groups regarding pain scores using a numerical rating scale, serum cortisol levels, total fentanyl, and morphine consumption, changes in mean arterial blood pressure (MAP) and heart rate (HR) during surgery, and the occurrence of postoperative complications. Results: Statistically significant reductions in pain scores were observed in group A compared to groups B and C. Moreover, group A exhibited a significant decrease in postoperative morphine consumption, serum cortisol levels 1 hour post-surgery (P = 0.021), MAP, and postoperative vomiting and nausea compared to group B. Furthermore, groups A and B showed statistically significant improvements in all parameters compared to group C. Conclusions: The study demonstrates that ESPB provides superior analgesic effects compared to SAPB in patients undergoing MRM, with reduced morphine use and lower postoperative cortisol levels. Both blocks offer more effective pain control than intravenous morphine alone.