Regional Analgesia Techniques Following Thoracic Surgery: A Systematic Review and Network Meta-analysis.

Background: Regional analgesia techniques have become the basis of multimodal analgesia for acute and chronic pain. They are widely used in thoracic surgery, but the best treatment is still uncertain.

Objectives: We aimed to compare and rank the effectiveness of regional analgesia techniques for thoracic surgery.

Study design: A systematic review and network meta-analysis.

Methods: PubMed, MEDLINE, Embase, Cochrane Library, Science-Direct, and Web of Science were searched for articles published from inception through the end of January 2023. The network meta-analysis was conducted using Stata 15.1 software (StataCorp, LLC). The certainty of evidence was assessed by using Confidence in Network Meta-analysis (CINeMA https://cinema.ispm.unibe.ch/ A (unibe.ch). The primary outcome was cumulative opioid consumption within postoperative 24 hours. The secondary outcomes included pain scores at postoperative 6 hours, 12 hours, and 24 hours.

Results: A total of 32 trials with 1,996 patients and 11 techniques were included. No major network inconsistency or heterogeneity were found. Postoperative opioid consumption within postoperative 24 hours was decreased most by continuous extrapleural block (cEPB) (standardized mean difference [SMD] = 0.00; 95% CI,: 0.00-0.00), followed by continuous thoracic epidural analgesia (cTEA) and continuous serratus plane block (cSAPB). In the postoperative 6 hour analysis, pain scores were  decreased most by cTEA (SMD = 0.16; 95% CI,: 0.05-0.49), followed by thoracic paravertebral block (TPVB) and ESPB (erector spinae plane block). In the postoperative 12 hour analysis, pain scores were decreased most by cSAPB (SMD = 0.12; 95% CI, 0.011.84), followed by TPVB and cTEA. In the postoperative 24 hour analysis, pain scores were decreased most by ESPB (SMD = 0.09; 95% CI, 0.030.32), followed by cSAPB and continuous thoracic paravertebral block (cTPVB).

Limitations: Our study has several limitations. First, 4 enrolled studies had a sample size of less than 40 patients. Second, the different regimens were potential factors contributing to heterogeneity, such as local anesthetic dose and volume, infusion time, infusion mode, adding adjuncts, and rescue analgesic regimens. Third, the number of primary and secondary outcomes is limited. Fourth, the number of randomized controlled trials for cEPB is limited.

Conclusions: The cTEA and cSAPB techniques are more likely to reduce the cumulative opioid consumption within 24 hours. The cTEA, cSAPB, ESPB techniques were more likely to improve pain at postoperative 6, 12, and 24 hours. Therefore, cTEA, cSAPB, and ESPB are the first choices for pain relief post thoracic surgery, whereas wound infiltration, intercostal block, continuous wound infiltration, and continuous intercostal block were less likely to be effective. We need more high-quality randomized controlled trials with larger sample sizes to validate our results and to determine the ideal regional analgesia technique and the optimal drug formula.