Background and aims The anesthetic characteristics of ultrasound-guided erector spinae plane block (ESPB) remain unclear. We conducted a study to clarify the analgesic efficacy of ESPB compared to that of thoracic paravertebral block (TPVB) for postoperative analgesia in video-assisted thoracic surgery (VATS).

Methods This study was a prospective randomized non-inferiority trial approved by the Institutional Review Board of Ehime Prefectural Central Hospital (No. 29–84, 02/03/2018). 88 patients scheduled for VATS were randomly allocated to either an ESPB or a TPVB group. Patients in both groups received continuous infusion of 0.2% levobupivacaine (8 mL/hour) after 20 mL of 0.2% levobupivacaine bolus injection. the primary outcome was postoperative numerical pain rating score (NRS) at rest 24 hours postoperatively, with a maximum acceptable difference (non-inferiority margin) between the groups in as 0.5. We also evaluated NRS during movement, amount of rescue fentanyl used, and the number of anesthetized dermatomes.

Results 81 patients completed the study. NRS at rest was significantly lower in the TPVB group at 1, 2, and 24 hours postoperatively (respective p values = 0.018, 0.008, and 0.030). There were no significant differences in NRS during movement. the median difference in NRS at rest 24 hours postoperatively was 1 (range 0–1), which failed to demonstrate non-inferiority. the number of anesthetized dermatomes at parasternal regions was significantly greater in the TPVB group (p < 0.0001). There were no statistically significant differences in rescue fentanyl use.

Conclusions This study suggests that the analgesic effect of ESPB for VATS was not equivalent compared to TPVB 24 hours postoperatively.