Comparison of Erector Spinae Plane Block With Serratus Anterior Plane Block for Breast Surgery

At lateral decubitus with the operation site up, the vertebrae will be counted from cephalad to caudal direction until reaching T5 spinous process as the first palpable spinous process is C7. The ultrasound probe will be placed vertically 3 cm lateral to the T5 spinous process. Three muscles will be identified superficial to the hyperechoic transverse process shadow as follows: trapezius, rhomboid major, and erector spinae. The needle will be introduced from superior to inferior direction in-plane until the tip lay deep to erector spinae muscle. 0.5: 1 mL of non-active fluid will be injected to confirm correct needle tip position by visualizing spread under erector spinae muscle. A total of 20 mL of 0.25% bupivacaine will be injected next.

At supine position with the arm abducted, the ribs will be counted in the mid-axillary line from downward upwards until the 5th ribs. The linear probe will be placed horizontally then three muscles will be identified: latissimus dorsi (superficial and posterior), teres major (superior) and serratus muscles (deep and inferior). The needle will be inserted in-plane with respect to the ultrasound probe from supero-anterior to posteroinferior. 0.5: 1 mL of non-active fluid will be injected to confirm correct needle tip position by visualizing spread over serratus anterior muscles, then a total 20 ml of bupivacaine 0.25% will be injected.