2.4 Application of block intervention
In the SAB group, an anesthetist with experience in interfascial blocks performed the ultrasound (US)-guided technique using a linear probe (6–12 MHz), a US device (LOGIQ e US system, Deutschland GmbH & Co. KG, Solingen, Germany), and a 21G x 80-mm echogenic needle. The patient is in supine position with 90-degree arm abduction, the US probe was positioned in a sagittal plane at the midaxillary line. There is a fascia plane between the fourth and fifth ribs in the middle axillary region, which is located between the serratus anterior muscle and the external intercostal muscle[9]. When the needle reached the fascia plane of the anterior serratus muscle and the external intercostal muscle, 20 mL 0.5% ropivacaine was given. ·
In the ESP group, The patient was in a lateral position. The T4 spinous process was determined, and the transducer was placed about 2-3 cm away from the midline in the longitudinal direction to identify the hyperechoic line of the transverse process and its related sound shadow. After determining the trapezius muscle, rhomboid major muscle and vertical spinal muscle group on the superficial surface of the transverse process. The tip of the needle (a 21G x 80-mm block needle) moves forward until it is located in the deep interfascial plane of the erector spinalis muscle group and above the transverse process. 0.5% ropivacaine 20mL was injected into the interfascial plane between the rhomboid major muscle and the erector spine muscle. Under the guidance of ultrasound, the local anesthetic spread to the depths of the erector spinae muscle in the mode of longitudinal fascia [12].
In the RIB group, The patient was placed in a lateral position with the affected breast at the top. Extend the ipsilateral arm to the same level of the ipsilateral chest and breast, and move the scapula outward. On the oblique sagittal plane, a high frequency (6-12 mhz) linear ultrasound probe was placed on the medial edge of the scapula. The US landmarks, trapezius muscle, rhomboid muscle, intercostal muscles, pleura, and lung were identified. Under aseptic condition, insert a 21G x 80m nerve block needle into the plan of the US probe at T5 to T6 levels. 0.5% ropivacaine 20mL was injected into the interfascial plane between the rhomboid major muscle and the intercostal muscle. Under the ultrasonic probe, the diffusion of ropivacaine in the fascia between the rhomboid muscle and the intercostal muscle can be visualized. Then the patient was positioned in supine position. All nerve blocks are performed by the same anesthesiologist, who has experienced with SAB, ESP and RIB block in more than 30 patients prior to nerve block.