The Effects of Erector Spinae Plane Block on Pain Scores in Unilateral Breast Cancer Surgery

The ESP block was performed unilaterally in the direction of the surgery by the same anesthetist. Blocks were performed using an Esaote ultrasound device (Esaote My Lab 6 US machine, Florence, Italy), a multifrequency convex probe (1-8 MHz), and a 22-gauge, 50 mm facet needle (B. Braun Sonoplex, Melsungen, Germany). The block needle was placed at the level of the T4 spinal process using the in-plane approach, approximately 3 cm lateral to the T4 spinous process in the parasagittal plane. After visualizing the transverse process with the in-plane approach, the 50 mm facet needle (B. Braun Sonoplex, Melsungen, Germany) was inserted through the skin, and a test dose of 1 ml of 0.9% NaCl was injected between the fascia of the trapezius, rhomboid, and erector spinae muscles and the transverse vertebral process to confirm the location. A total of 20 ml of 0.5% bupivacaine was used as a local anesthetic.