Comparison of subomohyoid plane block and interscalene nerve block for arthroscopic shoulder surgery

Abstract

Background: Ultrasound guided interscalene nerve block (ISB) is a popular procedure for pain relief in shoulder surgery patients. The subomohyoid plane block is a new reliable and technically easy regional technique that can be properly used for pain management with fewer adverse effects. The aim of this study was to validate whether there is a difference in postoperative pain scores and morphine consumption between interscalene and subomohyoid plane blocks. Method: Eighty patients scheduled for shoulder arthroscopy were enrolled in this controlled blinded study and randomized to interscalene or subomohyoid plane blocks using 15 ml 0.5% bupivacaine in each group and general anesthesia. The primary outcome was pain severity at rest using VAS. Secondary outcomes were first 24 h total morphine consumption, patient satisfaction and adverse effects. Results: All patients completed the study through the primary outcome analysis. VAS scores at PACU 2 h were similar in both groups, and VAS scores at 4, 8, 12,18 and 24 h were statistically lower in the interscalene block group (ISB) than in the subomohyoid group (p < 0.001), with no clinical significance. Total morphine consumption was lower in ISB group than in the subomohyoid group (p < 0.001). Time to the first rescue analgesic request and patients’ satisfaction were similar in both groups. Ipsilateral phrenic nerve was blocked in 37.5% of patients in ISB group vs. 7.5% in the subomohyoid group (p < 0.001). Conclusion: Subomohyoid plane block can be considered as an alternative to interscalene block for shoulder arthroscopy surgery.