Background and Objectives Single-incision transaxillary robotic thyroidectomy (START) requires substantial tissue disruption, which produces moderate-to-severe pain in the axilla and neck areas during the early postoperative period. This study aimed to investigate the analgesic effects of ultrasound-guided serratus-intercostal plane blocks and intermediate cervical plexus blocks (CPBs) on the early postoperative pain after START.

Methods We randomized 22 patients to undergo either ultrasound-guided serratus-intercostal plane and intermediate CPBs (the block group, n = 11) or to not undergo any block (the control group, n = 11). We compared postoperative axillary pain, postoperative neck pain, and analgesic use between the groups during the first 24 hours. The rescue analgesics were intravenous fentanyl (0.5 μg/kg) in the postanesthesia care unit, and intravenous ketorolac tromethamine (30 mg) in the general ward.

Results The block group showed consistently lower pain scores than the control group in the axillary area in the first 24 hours and in the neck area only in the first 3 hours after surgery. The numbers (proportions) of patients who required analgesics were 11 (100%) in the control group and 6 (54.5%) in the block group during the first 24 hours (P = 0.035). No adverse effect was observed related to the peripheral nerve blocks.

Conclusions After START, a serratus-intercostal plane block performed at the level of the third rib was an effective analgesic technique for axillary pain; however, the clinical effectiveness of intermediate CPB for neck pain may be limited.