Comparison of Postoperative Analgesic Efficacy of Serratus Posterior Superior Intercostal Plane Block and Serratus Anterior Plane Block in Modified Radical Mastectomy Surgery

This prospective, randomized, controlled clinical study is designed to compare the postoperative analgesic efficacy of the ultrasound-guided Serratus Posterior Superior Intercostal Plane (SPSIP) block and Serratus Anterior Plane (SAP) block in patients undergoing modified radical mastectomy under general anesthesia. Postoperative pain after breast cancer surgery remains an important clinical problem and may negatively affect respiratory function, early mobilization, recovery quality, patient satisfaction, and postoperative opioid consumption. Effective perioperative analgesia is therefore an essential component of enhanced recovery protocols in breast surgery.

Regional anesthesia techniques have increasingly been incorporated into multimodal analgesia strategies to reduce opioid-related adverse effects and improve postoperative pain control. The SAP block is widely used in breast and thoracic surgery due to its ability to provide analgesia to the lateral thoracic wall through blockade of the lateral cutaneous branches of the intercostal nerves. However, recently described fascial plane blocks such as the SPSIP block may provide broader dermatomal spread and more effective thoracic analgesia. Despite growing interest in the SPSIP block, evidence regarding its analgesic efficacy in breast surgery remains limited.

The study will include adult female patients scheduled for elective modified radical mastectomy under general anesthesia. Following enrollment and randomization, patients will be allocated to receive either ultrasound-guided SPSIP block or SAP block preoperatively in addition to standardized general anesthesia and multimodal analgesia protocols. All regional blocks will be performed under sterile conditions using ultrasound guidance by experienced anesthesiologists. Standard intraoperative monitoring will be applied throughout the surgical procedure.

Perioperative anesthetic management will be standardized as much as possible to minimize confounding factors affecting postoperative pain outcomes. Intraoperative opioid administration, hemodynamic parameters, and anesthetic requirements will be recorded. Postoperative analgesia protocols, including rescue analgesic administration criteria, will also be standardized for all participants.

The primary aim of the study is to evaluate and compare postoperative analgesic effectiveness between SPSIP and SAP blocks. Analgesic efficacy will be assessed using postoperative pain scores at predefined time intervals and cumulative opioid consumption during the postoperative period. Additional perioperative parameters related to recovery and analgesic quality will also be evaluated to determine the clinical utility of these interfascial plane blocks in breast surgery.