The role of low dose ketamine plus magnesium sulfate infusion versus dexmedetomidine infusion on postoperative pain in posterior spinal fusion surgery: Prospective randomized study

Abstract

Background: The fusion technique is often used to preserve the lumbar spine, reduce spinal cord injury, stabilize the spine, and relieve pain. The study compared the pain after posterior spinal fusion (PSF) surgery with small dosages of ketamine and magnesium sulfate (MgSO4) with dexmedetomidine infusion. Methods: This prospective randomized double-blind trial included 90 patients aged 21–60, both sexes, who were eligible for nontraumatic elective posterior spinal fixation surgery with two to five levels. Two equal groups of patients were formed: Group Ketamine and magnesium (KM): patients received low-dose KM sulfate (0.2 mg/kg bolus over 10 minutes, 0.12 mg/kg/hr. + Mg sulfate: 30 mg/kg bolus, 10 minutes, 8 mg/kg/hr) and Group Dexmedetomidine (D): patients received 0.5 μg/kg bolus over 10 minutes, 0.2 μg/kg/hr. Results: Numerical rating scale was insignificantly different at any time 24 hrs postoperatively between the two groups (p >0.05). The 1st time to rescue analgesia and total dose of opioid were insignificant difference between the two groups. Group D had a significant elevation in sedation levels (as measured by the Ramsey scale) in comparison to group KM. Conclusions: The use of ketamine plus magnesium sulphate or Dexmedetomidine as intraoperative infusion in PSF surgeries is effective in controlling pain, delaying 1st time of rescue analgesia, decreasing opioid consumption without any significant difference between the two groups as regard demographic data, level of pain control, 1st time to rescue analgesia or total dose of opioids except postoperative sedation which was more in group D than group KM.