Analgesic Efficacy of Combined PECS II and PIP Block Versus Thoracic Paravertebral Block Post-Mastectomy

Overview

Postoperative pain management is crucial for patients undergoing mastectomy for breast cancer. Regional analgesia techniques, such as the Thoracic Paravertebral Block (TPVB), are commonly used to reduce pain and opioid consumption; however, TPVB carries potential risks, including pneumothorax. Interfascial plane blocks, specifically the Pectoral Nerve II (PECS II) block combined with the Superficial Parasternal Intercostal Plane (PIP) block, have emerged as alternative techniques to provide comprehensive analgesia to both the lateral and anterior chest wall. The purpose of this randomized controlled trial is to evaluate and compare the analgesic efficacy and quality of postoperative recovery between a combination of ultrasound-guided PECS II and PIP blocks versus the standard Thoracic Paravertebral Block (TPVB) in patients undergoing mastectomy with or without axillary lymph node dissection (ALND). Participants will be randomly assigned to receive either the combined PECS II and PIP block or the TPVB following general anesthesia induction. Pain scores, total opioid consumption, time to first analgesic request, quality of recovery using the QoR-15 questionnaire, and potential block-related complications will be monitored and compared over the 24-hour postoperative period.

Breast cancer surgery, particularly mastectomy with or without axillary lymph node dissection (ALND), is associated with significant acute postoperative pain. Inadequate pain control in the immediate postoperative period can prolong hospital stay, delay functional recovery, and increase the risk of persistent post-mastectomy pain syndrome. While Thoracic Paravertebral Block (TPVB) has long been considered a gold standard for unilateral thoracic surgery analgesia, its technical difficulty and risk of serious complications such as pneumothorax and systemic toxicity prompt the search for safer alternatives. The PECS II block targets the lateral and medial pectoral nerves, intercostobrachial nerve, and lateral cutaneous branches of intercostal nerves T2-T6. However, it may not consistently cover the anterior cutaneous branches near the sternum. Combining the PECS II block with a Superficial Parasternal Intercostal Plane (PIP) block aims to provide complete coverage of both the lateral and anterior thoracic wall, potentially offering comparable or superior analgesia to TPVB with a lower complication profile. In this single-blind randomized controlled trial conducted at Dharmais Cancer Hospital, eligible female patients scheduled for mastectomy are randomized into two parallel groups: 1. Intervention Group: Receives an ultrasound-guided combination of PECS II block (25 mL 0.25% Bupivacaine) and Superficial PIP block (10 mL 0.25% Bupivacaine) prior to surgical incision. 2. Control Group: Receives an ultrasound-guided Thoracic Paravertebral Block at T4 and T6 levels (10 mL total of 0.25% Bupivacaine). Standardized general anesthesia and intraoperative monitoring (including hemodynamics and qNOX index for depth of analgesia) are maintained for all subjects. Postoperatively, patients receive standard oral paracetamol and IV ketorolac, supplemented with IV Morphine via a Patient-Controlled Analgesia (PCA) device. Study endpoints include Numeric Rating Scale (NRS) pain scores evaluated at rest and movement at 0, 6, 12, and 24 hours post-surgery; quality of recovery measured via the QoR-15 questionnaire at 24 hours; time to first PCA activation (duration of analgesia); total 24-hour morphine consumption; and monitoring for complications including local anesthetic systemic toxicity (LAST), hematoma, and pneumothorax.