The analgesic effects of bilateral superficial cervical plexus block in thyroid surgery: A systematic review and meta-analysis

Abstract

Background and aims: Thyroid surgery is moderately painful, and many techniques to reduce postoperative pain have been studied. Regional techniques are a part of multimodal analgesia employed for various surgical cases. Bilateral superficial cervical plexus block (BSCPB) is a commonly used regional anaesthesia technique for analgesia for thyroid surgery. A previous meta-analysis by this group had left questions about some facets of the technique, to which further trials have contributed.

Methods: The systematic review and meta-analysis was registered on the International Prospective Register of Systematic Reviews (PROSPERO) CRD42022315499. It is an update to a previously published paper in 2018. An updated systematic search, critical appraisal, and analysis of clinical trials were performed. Trials investigating preoperative or postoperative BSCPB compared to control in patients undergoing thyroid surgery were included in the search. The primary outcome was postoperative opioid consumption. The secondary outcomes were the duration of analgesia (time to request of analgesia), Visual Analogue Scale (VAS) pain scores at 0, 4, 12, and 24 h, postoperatively, rates of postoperative nausea and vomiting (PONV), postoperative rescue analgesic consumption, and intraoperative morphine use.

Results: A total of 31 studies and 2,273 patients were included in this analysis. BSCPB significantly reduced post-thyroidectomy opioid consumption (P < 0.001). Additionally, the duration of analgesia was prolonged following BSCPB. VAS scores for 24 h (postoperatively), intraoperative morphine use, and rescue analgesia (postoperatively) remained significantly lower in patients who received BSCPB. There was also a statistically significant reduction in PONV (P = 0.02).

Conclusion: BSCPB offers superior postoperative analgesia with a reduction in opioid use, reduction in PONV, and improvement in VAS scores.

Keywords: Analgesia; cervical plexus block; postoperative; thyroid surgery; thyroidectomy.

Figure 1

Flowchart according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Flowchart of searches of included and excluded studies; BSCPB = Bilateral superficial cervical plexus block

Figure 2

Forrest Plot of Primary Outcome. Forrest Plot demonstrates the morphine or equivalent required between bilateral superficial cervical plexus block (BSCPB) and no block/saline. The Forrest Plot shows that the no block/saline placebo group require more opiate compared to the BSCPB group. LM=Landmark, USG=Ultrasound, Pr=Preoperative, Po=Postoperative, B=Bupivacaine, BC=Bupivacaine + clonidine, SD=Standard deviation, CI=Confidence Interval

Figure 3

Subgroup analysis forest plots; point of injection for BSCPB; ultrasound versus landmark technique for bilateral superficial cervical plexus block (BSCPB); comparison between saline or no block and BSCPB, showing morphine/equivalent requirement benefit of using BSCPB. LM=Landmark, USG=Ultrasound, Pr=Preoperative, Po=Postoperative, B=Bupivacaine, BC=Bupivacaine + clonidine. SD=Standard deviation, CI=Confidence Interval

Figure 4

Risk of bias table. R=Ropivacaine, RC=Ropivacaine + clonidine, LM=Landmark, USG=Ultrasound, Pr=Preoperative, Po=Postoperative, B=Bupivacaine, BC=Vupivacaine + clonidine, L=Lignocaine

Figure 5

Trial sequential analysis of primary outcome horizontal brown lines depict the conventional threshold for statistical significance at P = 0.05. The outer and inner angled lines represent the adjusted threshold for statistical significance and the futility boundaries for 80% and 90% power, respectively