Analgesic efficacy of bilateral superficial cervical plexus block for thyroid surgery: meta-analysis and systematic review.

Background: Thyroid surgery is moderately painful, but is increasingly being considered as a day-case procedure. Bilateral superficial cervical plexus block (BSCPB) provides an adjuvant technique to facilitate this approach, but there is great evidential heterogeneity in randomised controlled trials (RCTs) about its use.

Methods: A systematic search, critical appraisal, and analysis of RCTs was performed. Trials investigating preoperative or postoperative BSCPB compared with control in patients undergoing thyroid surgery via neck incision were included. Odds ratio (OR) and 95% confidence interval (95% CI) were calculated for dichotomous data, whilst continuous data were analysed using standard mean difference. Primary outcome was rescue analgesic requirement in the first 24 postoperative hours. Secondary outcomes were visual analogue scale (VAS) scores at 0, 4, and 24 h, time until first analgesic request, intraoperative analgesic requirements, length of hospital stay, and incidence of postoperative nausea and vomiting (PONV).

Results: Fourteen RCTs published between 2001 and 2016 including 1154 patients were included. The overall effect of BSCPB compared with control showed a reduction in analgesic requirement (OR 0.30; 95% CI 0.18, 0.51; P<0.00001). There was improvement in VAS scores (P<0.002) and time to first analgesic requirement in the BSCPB group (P<0.00001). Length of hospital stay was reduced by 6 h by use of BSCPB. There was no significant change in the incidence of PONV with its use (OR 0.82; 95% CI 0.49-1.37; P=0.44).

Conclusions: BSCPB offers analgesic efficacy in the early postoperative period for up to 24 h after thyroid surgery, with reduced length of hospital stay, but without any beneficial effect on PONV.