PECS-II vs ESP in Nociception Level Index Guided Breast Surgery

The PECS-II block is an ultrasound-guided interfascial plane block designed to provide analgesia for surgeries involving the anterolateral chest wall, particularly breast surgery. It is an extension of the PECS-I block, which targets the medial and lateral pectoral nerves. In the PECS-II technique, a high-frequency linear ultrasound probe is used to identify the fascial planes. A 22G, 50 mm regional block needle is advanced in-plane under sterile conditions. A total of 30 mL of 0.25% bupivacaine is administered: 10 mL is injected between the pectoralis major and minor muscles (targeting the pectoral nerves), and 20 mL between the pectoralis minor and serratus anterior muscles (to block the lateral branches of intercostal nerves and intercostobrachial nerve).

The erector spinae plane (ESP) block is a fascial plane block performed under ultrasound guidance to provide multimodal analgesia for thoracic and abdominal surgeries, including breast procedures. In this technique, a high-frequency linear ultrasound probe is used to visualize the transverse process of the thoracic vertebra, typically at the T4-T5 level. With the patient in a seated position and under standard sterile conditions, a 22G, 50 mm regional block needle is inserted in-plane until the tip reaches the fascial plane between the erector spinae muscle and the transverse process. After negative aspiration, 1-2 mL of test dose is injected to confirm correct needle placement by observing separation of fascial layers. Then, 20 mL of 0.25% bupivacaine is injected incrementally.