Dexmedetomidine Versus Magnesium Sulfate in Ultrasound-Guided Bilateral Bi-Level Erector Spinae Plane Block in Corrective Scoliosis Surgery

Objectives: There is a scarcity of research regarding the effects of local anesthetic adjuvant drugs in erector spinae plane block (ESPB), especially in scoliosis surgery. This study aimed to compare dexmedetomidine (DEX) or magnesium sulfate (MgSO 4 ) as adjuvants for bupivacaine in bilateral bi-level ultrasound-guided ESPB (USG-ESPB) in patients undergoing corrective scoliosis surgery. Methods: In this prospective, randomized study, 60 patients aged 14 to 25 years were randomly assigned to 1 of 3 groups (in a 1:1:1 ratio) after induction of general anesthesia. The DEX group [n=20] received USG-ESPB with 20 mL of bupivacaine 0.125% plus 0.25 µg/kg of DEX for each injection, whereas the MgSO 4 group [n=20] received USG-ESPB with 20 mL of bupivacaine 0.125% plus 2 mg/kg MgSO 4 for each injection. The control group [n=20] received conventional perioperative analgesia. The primary outcome was time for the first rescue analgesia. Secondary outcomes included total morphine consumption and pain scores in the first 48 postoperative hours. Hemodynamic parameters were assessed. Results: The mean time to the first analgesic request was the longest among patients in the DEX group ( P <0.001). In addition, the total morphine consumption and the 48-hour time-weighted average pain score during rest and movement were significantly lower among the patients in the DEX group ( P <0.001). However, DEX was associated with a significant decrease in hemodynamic parameters ( P <0.001). Conclusion: Both DEX and MgSO 4 provided a satisfactory pain relief profile. However, DEX with bupivacaine provided a longer period of analgesia.