Comparative Evaluation of Pectoral Nerve Block Type II Versus Rhomboid Intercostal and Subserratus Plane Block in Breast Cancer Mastectomy for Postoperative Analgesia: a Randomized, Controlled Trial

In the PECS II group,once the needle tip reached the fascial plane between the pectoralis minor and serratus anterior muscles and there was no blood aspiration, 15 mL of 0.375% ropivacaine was injected. Then the needle was withdrawn until the needle tip reached the fascial plane between the pectoralis major and pectoralis minor muscles, and another 15 mL of 0.375% ropivacaine was injected. After the nerve block was implemented, the area of sensory block was marked, and the spread of the local anesthetic was monitored by ultrasound. Alcohol swabs and pinprick tests were used to detect cold and pain sensations.

In the RISS group,the linear ultrasound probe was placed in the sagittal plane at the level of the 5th to 6th thoracic vertebrae (T5-6), just medial to the scapula, to identify the trapezius, rhomboid major, and intercostal muscles. A 21-gauge puncture needle was inserted in a cranial-to-caudal direction into the plane between the rhomboid major and intercostal muscles. When there was no blood aspiration, 20 mL of 0.375% ropivacaine was injected. After that, the ultrasound probe was moved caudally and laterally to identify the tissue plane between the serratus anterior and external intercostal muscles for performing the subserratus block at the level of the 8th to 9th thoracic vertebrae (T8-9). The puncture needle was advanced from the previous position, and when there was no blood aspiration again, an additional 20 mL of 0.375% ropivacaine was injected.