Fig. 1. Surgical incision and technique of the ESPB. Total mastectomy with sentinel lymph node dissection was performed (A). The level of the T5 rib and TP was located using a counting-down approach from the first rib; this was marked on the skin (B). After placing a 5–12 MHz linear probe parallel to the vertebral axis, a needle was inserted, in a caudad-to-cephalad direction, toward the TP of T5 (C). Then, the catheter was inserted and secured by suture to the skin (D).

ESPB = erector spinae plane block, TP = transverse process.