Comparison of Erector Spinae Plane Block and Retrolaminar Block for Postoperative Analgesia After Video-Assisted Thoracoscopic Surgery: A Randomized Controlled Trial

Abstract Background: This study aimed to compare postoperative pain intensity at rest, assessed using the Numerical Rating Scale (NRS) at 1, 6, 12, and 24 hours, between ultrasound-guided erector spinae plane (ESP) and retrolaminar blocks in patients undergoing video-assisted thoracoscopic surgery (VATS). Secondary outcomes included postoperative rescue analgesic requirements, time to first rescue analgesia, intraoperative remifentanil consumption, and adverse events. Methods: In this prospective, randomized, assessor-blinded trial, 54 patients with American Society of Anesthesiologists (ASA) physical status I (n = 5) or II (n = 49) undergoing VATS were allocated to receive either an ESP block (n = 27) or a retrolaminar block (n = 27). Both blocks were performed under ultrasound guidance after induction of general anesthesia and before surgery, using 30 mL of 0.5% bupivacaine and 10 mL of 2% lidocaine (40 mL; dose reduced to bupivacaine 1 mg/kg and lidocaine 2 mg/kg in patients weighing < 60 kg). The primary outcome was pain intensity at rest, assessed using the NRS at 1, 6, 12, and 24 hours postoperatively. Rescue analgesia (tramadol, then diclofenac) was offered when NRS exceeded 4. Postoperative rescue analgesic requirements, intraoperative remifentanil consumption, and adverse events were recorded. Post hoc longitudinal sensitivity analyses were performed using a linear mixed-effects model and an ordinal generalized estimating equations model. Results: NRS scores at rest did not differ significantly between the groups at any time point; the Hodges–Lehmann median differences (ESP minus retrolaminar) were 1 (95% CI, 0 to 3) at 1 hour (p = 0.069) and 0 (95% CI, 0 to 1) at 6, 12, and 24 hours (p = 0.941, 0.192, and 0.217, respectively). In a post hoc linear mixed-effects analysis, the group-by-time interaction was not significant (p = 0.117). Rescue analgesic requirements, total tramadol consumption (p = 0.854), and intraoperative remifentanil consumption across all randomized patients (p = 0.101) did not differ significantly between groups. No local anesthetic systemic toxicity or block-related complications were observed. Conclusions: In patients undergoing VATS, no statistically significant differences in postoperative pain scores at rest or rescue analgesic requirements were observed between ESP and retrolaminar blocks. However, the confidence intervals, particularly at the first postoperative hour, do not exclude clinically relevant differences, and these findings do not establish equivalence between the two techniques. Trial registration: ClinicalTrials.gov, NCT07830290. Registered on 21 September 2026 – Retrospectively registered, https://clinicaltrials.gov/study/NCT07830290.