The Efficacy of Serratus Posterior Superior Interfacial Plane Block on Postoperative Pain Control in Female Patients Underwent Mastectomy and Axillary Lymph Node Dissection: A Randomized, Prospective, Controlled Study

Mastectomy and axillary lymph node dissection are among the most frequently performed surgeries today, and pain control is an important problem affecting patient comfort in the postoperative period in these patients. Postoperative pain is an acute pain associated with the inflammatory process that occurs due to surgical trauma and gradually decreases with tissue healing. Several analgesic drugs such as opioids are used to prevent this pain, but these agents have many unwanted side effects. Successful postoperative analgesia occurs in the patient due to pain; it is a known fact that it prevents many of the effects such as not being able to breathe easily and delayed mobilization.

Regional techniques can be used for postoperative pain control following breast surgery. Ultrasound (US) guided serratus posterior superior block (SPSIPB) is a new interfacial plane block defined by Tulgar et al in 2023. It is based on injection on the serratus posterior superior muscle at the level of the 2nd or 3rd rib. This block provides analgesia in conditions such as interscapular pain, chronic myofascial pain syndromes, scapulocostal syndrome, and shoulder pain. The SPS muscle is located at the C7-T2 level. It attaches to the lateral edges of the second and fifth ribs. It is innervated by the lower cervical and upper intercostal nerves. With the SPS block, these nerves are blocked and analgesia is provided.

In the cadaveric study of Tulgar et al., it was determined that the spread of serratus posterior superior interfacial plane block; 7-10 intercostal levels on the left side only in the superficial fascia of the trapezius muscle. Spread dye was observed at intercostal levels, absent on the right. There was prominent staining on both sides of the deep trapezius muscle. Both the surface and skin of the rhomboid major were clearly stained, while the rhomboid minor was only stained in the skin. SPSP block will provide successful analgesia in procedures involving the thoracic region such as chronic myofascial pain, breast surgery, thoracic surgery, and shoulder surgery.

In this study, our aim is to investigate the efficacy of US-guided SPSIPB for postoperative analgesia management after mastectomy and axillary lymph node dissection surgery. Our primary aim is to compare postoperative pain scores (NRS), and our secondary aim is to evaluate the need for rescue analgesics, block-related complications, dermatome level, and side effects (allergic reaction, nausea, vomiting) associated with opioid use.