METHODS: A prospective, double-blinded randomized controlled trial comparing the post-operative pain score between BSCPB and LWI was conducted among patients undergoing thyroid surgery. Ropivacaine 0.50% was used in the study. Pain score was measured at 4, 12, 16 and 24 h after surgery using the visual analog scale (VAS). Subcutaneous injection of Tramadol was given whenever the pain score was ≥4 or requested by patients.

RESULTS: A total of 70 patients were recruited, with 35 patients on each arm. There was no statistical difference in the post-operative pain score between the two groups at 4 h (p = 0.208), 12 h (p = 0.860), 16 h (p = 0.376) and 24 h (p = 0.375) after surgery. Time to the first rescue dose of Tramadol between the two arms was also insignificant (p = 0.949). One patient in the BSCPB arm developed transient left upper limb weakness, which resolved 12 h after surgery.