Methods
Patients undergoing elective lower-thoracic and lumbar spinal fusion were randomised into two groups: the case group (n = 15) who received erector spinae plane block (ropivacaine 0.4% + dexamethasone 4 mg, 20 mL per side at the level of surgery) plus postoperative opioid analgesia, and the control group (n = 15) who received opioid-based analgesia.