Comparison between ultrasound guided serratus anterior plane block and rhomboid intercostal plane block for postoperative analgesia in patients undergoing modified radical mastectomy- A randomized controlled trial

Surgery on the chest wall is relatively common and can be associated with considerable postoperative discomfort and pain. Breast cancer is a common cancer affecting women, accounting for 31% of all new cancer cases1,2. Modified radical mastectomy (MRM), commonly performed in patients of breast cancer, causes significant acute pain in 8-25% of patients and if not treated adequately may progress to chronic pain states in 25–60% of cases3. Regional blocks for breast surgery reduce post-operative pain, opioid requirement, nausea and vomiting and duration of stay in post anesthesia care unit4.

Various regional anesthesia techniques with varying efficacy have been described for management of post-operative pain following breast surgery. These include thoracic epidural or paravertebral block, intercostal nerve block, pectoral nerve blocks and the newer USG guided fascial plane blocks like serratus anterior plane block (SAP) and rhomboid intercostal plane block (RIPB)5.

 Serratus anterior plane block (SAP) 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 region6. It has shown to reduce postoperative opioid consumption7.

 Rhomboid intercostal plane block (RIPB) is a new fascial block technique described by Elsharkawy et al8 in 2016. RIPB is easier and can be performed reliably with the point of entry away from the involved/ surgical area. The block provides analgesia for the anterior and posterior thorax and has been studied extensively for thoracic surgeries. However, it has not been studied much for MRM, but the few available studies have reported enhanced recovery and decreased opioid consumption after mastectomy9.

AlthoughSAP block has been extensively studied for breast surgery, RIPB in spite ofbeing efficacious for post-operative analgesia after major thoracic surgery, isstill under-evaluated for MRM. Though they have been compared with differentblocks, literature is sparse with regards to the comparable analgesic efficacyof SAP and RIPB in MRM. This study is therefore being planned to compare theefficacy of the two blocks in MRM.