Abstract
BACKGROUND AND AIMS: Regional techniques are preferred for controlling post-thoracotomy pain due to lower complication rates. This study aimed to compare the analgesic efficacy and safety of ultrasound-guided external oblique intercostal block (EOIB) with thoracic erector spinae plane block (ESPB) for post-thoracotomy pain. METHODS: This randomised, double-blind, non-inferior clinical study involved 60 cases scheduled for thoracic surgery. Cases were randomly allocated into two groups: ESPB and EOIB groups. Using 30 mL 0.25% bupivacaine at the level of the thoracic vertebrae 5, both blocks were performed after induction of general anaesthesia. The primary outcome was morphine consumption in the first 24 hours postoperatively. The secondary outcomes were time to first rescue analgesic request postoperatively, numerical rating scale (NRS) score during rest and with coughing, and occurrence of complications. The non-parametric Wilcoxon test was used for non-normally distributed variables, the Student's t-test was used for normally distributed variables, and the Chi-square/Fisher's exact test was used for qualitative variables. The significance level was set at P ≤ 0.05. RESULTS: Patients who required intraoperative fentanyl, time of first request for analgesia, total morphine consumption, and pain score within the first 24 hours post-surgery were comparable between the two groups (P = 0.347, 0.085, and 0.354, respectively). Both groups exhibited comparable incidences of hypotension and bradycardia (P = 0.353 and P > 0.99, respectively). Local anaesthetic systemic toxicity (LAST) and pneumothorax did not occur in any patient in either group. CONCLUSION: The analgesic effect of EOIB was non-inferior to ESPB for post-thoracotomy pain, as evidenced by comparable total opioid consumption, time of first request for analgesia, and pain score in the first 24 hours post-surgery. Additionally, EOIB demonstrated the same level of safety as ESPB.