Background and objectives The serratus plane block (SPB) is a novel chest wall interfascial plane block. Its analgesic efficacy compared with non-block care and paravertebral block (PVB) is unestablished.

Methods We conducted a random-effects meta-analysis of randomized controlled trials (RCTs) recruiting adult surgical patients that compared a SPB to non-block care or PVB for postoperative analgesia. Visual analog scale pain scores were the primary outcome. Database sources were Medline, Embase, the Cochrane Library, and Google Scholar searched up to July 29, 2019 without language restriction. Risk of bias was assessed using Cochrane methodology.

Results Nineteen RCTs that comprised 1260 patients were included. Six trials involved thoracic surgery patients and 13 studied breast surgery patients. SPB reduced pain scores 0 hour postoperatively (−1.62 cm; 99% CI −2.43 to −0.81; p<0.001; I²=92%), at 2–4 hours (−1.29 cm; 99% CI −2.08 to −0.49; p<0.001; I²=92%), at 6 hours (−1.69 cm; 99% CI −3.19 to −0.20; p=0.004; I²=99%), and up to 24 hours compared with non-block care. SPB also prolonged the time to first analgesic request (193.2 min; 95% CI 7.2 to 379.2 min; p=0.04; I²=99%), reduced 24-hour postoperative opioid consumption (−11.27 mg of IV morphine equivalent; −17.36 to −5.18 mg; p<0.001), and reduced postoperative nausea and vomiting (RR 0.51; 95% CI 0.38 to 0.68; p<0.001; I²=12%). In contrast, no meaningful differences were detected in any of the outcomes for the SPB versus PVB data.

Conclusions SPB reduced postoperative pain scores (Grading of Recommendations Assessment, Development, and Evaluation rating: low; due to heterogeneity and deficiencies in blinding) in breast and thoracic surgery patients compared with non-block care. Based on five trials only, SPB was not appreciably different from PVB.