Open Versus Ultrasound Approach for Serratus Anterior Block

After induction of general anesthesia, the ultrasound probe will be placed longitudinally oblique just below the mid-clavicle. After identifying the second rib, the probe will be moved caudally and laterally (obliquely), towards the mid-axillary line to identify the 3rd, 4th and 5th ribs.. The fascial plane between the serratus anterior muscle and latissimus dorsi muscle will be identified over the 4th rib in the mid-axillary region. The block will be performed with a needle (22-G, 50-mm) introduced in-plane to enter deep to the serratus anterior muscle, and 30 ml 0.25 bupivacaine will be injected.

After resection of the breast and identification of the serratus anterior muscle, the surgeon will be asked to palpate the ribs below the clavicle and localize the fourth rib. A 22-G, 50-mm needle will be introduced deep to the serratus anterior muscle contacting the rib, and 30 ml 0.25 bupivacaine will be injected.