Comparison between ultrasound guided serratus posterior superior intercostal plane block and serratus anterior plane block for post-operative analgesia in patients undergoing modified radical mastectomy- A randomised controlled study.

Surgical interventions for breast cancer including breast conservation surgery, modified radical mastectomy (MRM) and lumpectomy are widespread due to the high incidence of breast cancer globally. These surgeries are essential components of breast cancer treatment. Since it affects the postoperative recovery and mobilization, pain after breast surgery is an important issue. Breast surgery presents unique pain challenges due to the complexity of the breast anatomy and the potential for extensive tissue manipulation and ineffective pain relief by oral analgesics, necessitating the exploration of advanced regional anesthesia techniques.

These include thoracic epidural or paravertebral block, intercostal nerve block, pectoral nerve blocks and the newer USG guided fascial plane blocks like erector spinae plane block (ESPB), rhomboid intercostal plane block (RIPB), serratus anterior plane block (SAPB) and Serratus posterior superior intercostal plane block (SPSIPB).

Serratus anterior plane block (SAPB) was first proposed by Blanco et al in 2013, and provides good postoperative analgesia after MRM. It blocks T2-T9 intercostal nerves and provides analgesia over the chest wall and axillary region.3

Recently an interfascial plane block technique: Serratus posterior superior intercostal plane block has been described. It is performed between serratus posterior superior muscle (SPSm) which is a periscapular muscle and intercostal muscles. Due to its features, injecting local anesthetic (LA) deeply into the SPSm results in coverage of dorsal ramus and lateral cutaneous branches of intercostal nerves at C3 to T10 levels. Given SPSIPB’s sensory dermatome, it has been demonstrated that it can provide analgesia in the hemithorax, shoulder, and back of the neck.

Although SAPB is a proven and efficacious method for providing effective post operative analgesia in patients undergoing MRM, breast cancers associated with fungating mass, local infection and inflammation may pose challenges to perform SAPB. Given SPSIPB’s sensory dermatome, it may provide analgesia for surgical procedures involving the breast. There is paucity of studies on the role of SPSIPB in pain control on breast surgeries. Therefore this study is being planned to compare the postoperative analgesia provided by the two blocks in patients undergoing MRM.