Dexmedetomidine versus Magnesium Sulphate in Ultrasound-Guided Bilateral bi-Level Erector Spinae Plane Block in Corrective Scoliosis Surgery: A Randomized Controlled Clinical Trial.

Objective: There is a scarcity of research regarding the effects of LAs adjuvant drugs in erector spinae plane block (ESPB), especially in scoliosis surgery. This study aimed to compare dexmedetomidine (DEX) or magnesium sulfate (MgSO₄) 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, sixty patients aged 14 to 25 years were randomly assigned to one of three 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, while the MgSO4 group [n=20] received USG-ESPB with 20 mL of bupivacaine 0.125% plus 2 mg/kg MgSO4 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 assisted.

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-h time-weighted average pain score during rest and movement were significantly lower among the patients in the DEX group (P<0.001). However, it was associated with a significant decrease in hemodynamic parameters (P<0.001).

Conclusions: Both DEX and MgSO₄ provided a satisfactory pain relief profile. However, DEX with bupivacaine provided a longer period of analgesia.