Effects of Perineural Dexamethasone and Dexmedetomidine on Neuromonitoring and Analgesia in Pediatric Scoliosis Surgery

Study Design. A randomized controlled trial (RCT). Objective. To evaluate the effects of dexamethasone and dexmedetomidine as adjuvants to the erector spinae plane block (ESPB) on motor-evoked potential (MEP) recordings, postoperative analgesia, and hemodynamic stability in pediatric scoliosis surgery. Summary of Background Data. Intraoperative neuromonitoring using MEPs is crucial for assessing spinal cord integrity during scoliosis surgery. The ESPB is widely used for postoperative pain management; however, its impact on neuromonitoring remains uncertain, especially when combined with perineural adjuvants. Methods. Ninety pediatric patients undergoing scoliosis correction surgery were randomized into three groups: (1) Control (ESPB with 0.2% ropivacaine), (2) DEX (ropivacaine + 0.1 mg/kg dexamethasone), and (3) DEM (ropivacaine + 0.1 µg/kg dexmedetomidine). The primary outcome was time to first opioid analgesia. Secondary outcomes included total opioid consumption, postoperative pain scores, MEP amplitude and latency, transcranial electrical stimulation (TES) intensity required to evoke MEP, and hemodynamic stability. Results. Both adjuvants significantly prolonged analgesia and reduced opioid consumption ( P <0.0001). Pain scores (NRS) at 8, 12, 16, and 24 hours were lower in both adjuvant groups compared to the control. Dexamethasone was associated with the highest MEP amplitudes post-surgical correction and required lower TES intensity ( P =0.04), indicating superior neuromonitoring conditions. Dexmedetomidine was linked to lower MEP amplitudes and increased incidence of bradycardia (11 patients), whereas intraoperative hypotension occurred in five DEX patients. Conclusions. Dexamethasone improves neuromonitoring conditions by enhancing MEP amplitudes and reducing TES requirements, whereas dexmedetomidine is associated with MEP suppression and hemodynamic instability. These findings highlight the importance of balancing analgesia with neuromonitoring integrity in pediatric scoliosis surgery.