Analgesic efficacy of PECS and serratus plane blocks after breast surgery: A systematic review, meta-analysis and trial sequential analysis.

STUDY OBJECTIVE: To determine whether pectoral nerves (PECS) blocks provide effective postoperative analgesia when compared with no regional technique in patients undergoing breast surgery.

DESIGN: Systematic review, meta-analysis and trial sequential analysis.

SETTING: Operating room, postoperative recovery area and ward, up to 24 postoperative hours.

PATIENTS: Patients undergoing breast surgery under general anaesthesia with either PECS block or no regional technique.

INTERVENTIONS: We searched five electronic databases for randomized controlled trials comparing PECS block with no block or sham injection.

MEASUREMENTS: The primary outcome was rest pain scores (analogue scale, 0-10) at 2 h, analysed according to surgery (mastectomy vs other breast surgery) and regional technique (PECS 2 vs other blocks), among others. Secondary outcomes included morphine equivalent consumption, and rate of postoperative nausea and vomiting at 24 h.

MAIN RESULTS: Sixteen trials including 1026 patients were identified. Rest pain scores at 2 h were decreased in the PECS blocks group, with a mean (95%CI) difference of -1.5 (-2.0, -1.0); I2 = 93%; p < 0.001, with no differences between surgery (mastectomy, mean difference [95%CI]: -1.8 [-2.4, -1.2], I2  = 91%, p < 0.001; other breast surgery, mean difference [95%CI]: -1.1 [-2.1, -0.1], I2  = 94%, p = 0.03; p for subgroup difference = 0.25), and regional technique (PECS 2, mean differences [95%CI]: -1.6 [-2.3, -1.0], I2  = 94%, p < 0.001; other blocks, mean differences [95%CI]: -1.3 [-2.4, -0.1], I2  = 74%, p = 0.04; p for subgroup difference = 0.57). The rate of postoperative nausea and vomiting was reduced from 30.8% (95%CI: 25.7%, 36.3%) to 18.7% (95%CI, 14.4%, 23.5%; p = 0.01). Similarly, secondary outcomes were significantly improved in the PECS blocks group. The overall quality of evidence was moderate-to-high.

CONCLUSIONS: There is moderate-to-high level evidence that PECS blocks provide postoperative analgesia after breast surgery when compared with no regional technique and reduce rate of PONV. This might provide the most benefit to those at high-risk of postoperative pain.