Comparison Between Preemptive Erector Spinae Plane Block Versus Serratus Anterior Plane Block on Postoperative Analgesia for Patients Undergoing Modified Radical Mastectomy: A Randomized Clinical Trial

The patients were placed in lateral decubitus position with the operation site up. The probe was placed vertically 3 cm lateral to the T5 spinous process, and the transverse process was identified as an oval hyperechoic sonographic structure. The needle was introduced in an in-plane fashion until the tip lay deep in the erector spinae muscle. 0.5 mL of normal saline was injected to confirm the correct needle tip position by visualizing the spread under the erector spinae muscle. A total of 0.4 mL kg-1 of 0.25% bupivacaine was injected. between the erector spinae muscle and transverse process.

Serratus anterior plane block was administered to patient in the supine position with ipsilateral arm abducted to 90°. Under aseptic precautions, linear probe was placed over the midclavicular region in the sagittal plane. Ribs were counted inferiorly and laterally until the fifth rib was identified in midaxillary line. Latissimus dorsi, teres major, and serratus anterior muscles were identified overlying the fifth rib. The intended puncture site was infiltrated with 2 mL of 2% lignocaine, and using ultrasound-guided in-plane approach, the needle was introduced in caudal to cranial direction until the tip was placed between the serratus anterior muscle and external intercostal muscle.