Dexamethasone as an Adjuvant to Erector Spinae Plane Block Is Associated With Improved Neuromonitoring Parameters and Analgesia in Pediatric Spine Surgery.

Abstract

Posterior spinal fusion for idiopathic scoliosis in children and adolescents is associated with severe postoperative pain and high opioid requirements. The erector spinae plane block (ESPB) provides effective analgesia, but its duration is limited. Dexamethasone prolongs peripheral nerve blocks in adults; however, its effects on analgesia and neurophysiological parameters in pediatric spine surgery remain unclear. To evaluate whether dexamethasone administered within the fascial plane as an adjuvant to ESPB is associated with prolonged analgesia, reduced opioid consumption, and changes in motor neurophysiological parameters in pediatric scoliosis surgery. Prospective, randomized, double-blind, controlled clinical trial conducted at a tertiary university hospital. Sixty children and adolescents aged 10-18 years with Lenke type 3 scoliosis undergoing posterior spinal fusion were randomized to receive ESPB with ropivacaine 0.2% plus dexamethasone (0.1 mg/kg; DEX group, n=30) or ropivacaine 0.2% alone (NO DEX group, n=30). Primary outcome was time to first rescue opioid analgesia within 48 hours postoperatively. Secondary outcomes included total opioid consumption, postoperative pain scores (Numerical Rating Scale, NRS), perioperative blood glucose levels, neurological complications, intraoperative motor evoked potentials (MEPs), and postoperative electroneurography (ENG) parameters. Bilateral ultrasound-guided ESPBs were performed at T4 and T10 after anesthesia induction. Neuromonitoring included intraoperative transcranial electrical stimulation-elicited MEPs and postoperative transcranial magnetic stimulation-elicited MEPs, as well as postoperative motor ENG of the peroneal nerves. Pain scores and opioid consumption were recorded by blinded assessors. Appropriate parametric and non-parametric tests, including repeated-measures analyses, were applied. Time to first opioid administration was longer in the DEX group than in the NO DEX group (13.0 ± 2.1 h vs. 5.2 ± 1.6 h; p<0.0001). Total opioid consumption during the first 48 hours was lower in the DEX group (18.1 ± 3.8 mg vs. 27.3 ± 4.4 mg morphine equivalents; p<0.0001). NRS pain scores were lower at 8, 12, and 24 hours postoperatively (p<0.05). Neurophysiological assessments showed higher postoperative MEP amplitudes and more favorable ENG parameters in the DEX group compared with the NO DEX group; overall postoperative improvement in neurophysiological measures was observed in both groups. No differences in perioperative blood glucose levels or neurological complications were detected. In pediatric scoliosis surgery, dexamethasone administered within the fascial plane as an adjuvant to ESPB is associated with prolonged analgesia and reduced opioid requirements without increasing adverse effects. Differences in neurophysiological parameters between groups should be interpreted as associations and may reflect modulation of perioperative conditions rather than a direct neuroprotective effect. Overall postoperative neurophysiological improvement is likely related to surgical scoliosis correction.