Ultrasound-guided bilateral superficial cervical block and preemptive single-dose oral tizanidine for post-thyroidectomy pain: a randomized-controlled double-blind study.

Abstract

The postoperative analgesic effect of tizanidine has not yet been evaluated sufficiently. The role of bilateral superficial cervical plexus block (BSCPB) for postoperative analgesia after thyroidectomy remains questionable. We aimed to evaluate the analgesic effect of combined use of BSCPB and a single-dose oral tizanidine in patients undergoing elective thyroid surgery. Sixty patients undergoing thyroidectomy were randomized into 3 groups. The control group (Group C, n=20) received BSCPB with 0.9% saline plus oral placebo. The superficial cervical group (Group SC, n=20) received BSCPB with 0.25% bupivacaine plus oral placebo. The superficial cervical and tizanidine group (Group SC+T, n=20) received BSCPB with 0.25% bupivacaine plus tizanidine 6mg capsule. Surgical site pain scores, opioid consumption, rescue analgesia, posterior neck pain, headache, and opioid-related side effects were assessed for the first 24h. Compared with Group C, rest and swallowing pain scores in Group SC and Group SC+T were statistically lower at all postoperative time points (p<0.05). Fentanyl consumption was lower in Group SC and Group SC+T than in Group C at time periods 0-4 and 4-8h (p<0.05). Fentanyl consumption was lower in Group SC+T than in Group SC at 0-4h (p=0.006). Total fentanyl consumption was higher in Group C than in the other groups (p<0.001). Postoperative cervical pain and occipital headache were significantly lower in Group SC+T than in the other groups (p<0.05). Ultrasound-guided BSCPB with or without preemptive oral tizanidine was effective at reducing postoperative pain and opioid consumption in patients undergoing total thyroidectomy. Addition of preemptive oral tizanidine to BSCPB reduced the early postoperative opioid consumption, posterior neck pain, and occipital headache. The study was registered with a clinical trials registry (ClinicalTrials.gov. identifier NCT02725359).