Serratus anterior plane block for video-assisted thoracoscopic surgery A meta-analysis of randomised controlled trials

BACKGROUND The serratus anterior plane block (SAPb) is a promising interfascial plane technique able to provide profound thoracic analgesia. As only a few studies with quite small patient samples are presently available, the analgesic efficacy of adding SAPb to general anaesthesia in video-assisted thoracoscopic surgery (VATS), compared with general anaesthesia only, remains unclear. OBJECTIVES Our primary aim was to assess the analgesic efficacy of SAPb for VATS peri-operative pain control. The secondary aims were to evaluate differences in postoperative opioid use, intra-operative hypotension, postoperative side-effects and complications, time to chest tube removal, length of hospital stay. DESIGN Systematic review of randomised controlled trials (RCTs) with meta-analyses. DATA SOURCES PubMed, Web of Science, Google Scholar and the Cochrane Library, searched up to 6 December 2019. ELIGIBILITY CRITERIA RCTs including adult patients undergoing VATS who received single shot SAPb (cases), compared with general anaesthesia (controls). RESULTS Seven RCTs, with a total of 489 patients were included. SAPb reduced pain scores peri-operatively, compared with controls: 6 h [mean difference -1.86, 95% confidence interval (CI) -2.35 to -1.37, P < 0.001]; 12 h (mean difference -1.45, 95% CI -1.66 to -1.25, P < 0.001); 24 h (mean difference -0.98, 95% CI -1.40 to -0.56, P < 0.001). SAPb also reduced the use of postoperative opioids (mean difference: -4.81mg of intravenous morphine equivalent, 95% CI -8.41 to -1.22, P < 0.03) and decreased the incidence of nausea and vomiting (risk ratio 0.53, 95% CI 0.36 to 0.79, P < 0.002). CONCLUSION Compared with general anaesthesia only and if no other locoregional techniques are used, SAPb significantly reduces postoperative pain and nausea and vomiting in patients undergoing VATS. Grading of Recommendations Assessment, Development and Evaluation rating are, nonetheless, quite low, due to high heterogeneity. Well designed and properly powered RCTs are necessary to confirm these preliminary findings.