Effect of Intraoperative Phrenic Nerve Infiltration on Postoperative Ipsilateral Shoulder Pain After Thoracic Surgeries: A Systematic Review and Meta-Analysis of Randomized Controlled Studies

OBJECTIVES:This meta-analysis was aimed at investigating the effectiveness and safety of phrenic nerve infiltration (PNI) against ipsilateral shoulder pain (ISP) after thoracic surgery. DESIGN:A systematic review and meta-analysis of randomized controlled trials (RCTs). SETTING:Operating room. PARTICIPANTS:Patients undergoing thoracic surgery. INTERVENTIONS:PNI. MEASUREMENTS AND MAIN RESULTS:MEDLINE, Cochrane Library, and EMBASE databases were searched from inception through December 2021. The primary outcome was the overall incidence of ISP, with secondary outcomes including incidence and severity of ISP at postoperative 6, 24, and 48 hours. Six RCTs involving 482 patients undergoing thoracic surgery were included. Pooled results found a significantly lower incidence of overall ISP in patients with PNI (ie, 23.6%) compared to those without (ie, 53.2%; risk ratio: 0.46, 95% confidence interval: 0.34-0.61; I2 = 19%; 6 RCTs; n = 474; certainty of evidence = high). At postoperative 6, 24, and 48 hours, there was also a significantly lower incidence of ISP in the PNI group than in the control group (certainty of evidence for all outcomes = high). Besides, the severity of ISP was lower in the PNI group at 6 (certainty of evidence = moderate) and 24 hours (certainty of evidence = high), with insufficient data for analysis at 48 hours because of only 1 trial. CONCLUSION:This meta-analysis showed that PNI not only reduced the incidence but also improved the severity of ipsilateral shoulder pain after thoracic surgery with a prophylactic effect lasting up to 48 hours. The limited number of included studies warrants further research to support these findings.