Ultrasound Guided Erector Spinae Block Using Bupivacaine – Magnesium Sulphate versus Bupivacaine – Dexmedetomidine for Postoperative Analgesia in Lumbar Spine Surgeries

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Abstract Purpose Lumbar spine surgeries are associated with significant postoperative pain. Erector Spinae Plain Block (ESPB) is a new ultra-sound guided block technique for such surgeries . We aimed to explore the analgesic effect of adding dexmedetomidine and magnesium sulfate as adjuvants to bupivacaine in ESP. Patients and Methods Fifty two patients scheduled for lumbar spine surgery were randomly allocated into two groups to receive an ESP block., A total volume of 25 ml, [10 mL 0.5% bupivacaine diluted in normal saline (NS) and 2 mg/kg MgSO4 in group (MG group) and 10 mL 0.5% bupivacaine in NS with 2 μg/kg dexmedetomidine in group (DEX group)] were injected. The block was administered preoperatively before anesthesia induction. Postoperatively, hemodynamics, visual analog scale scores, the first request for analgesia, total analgesic consumption, and side effects were observed for 12 hours. Results The demographic data including age, gender, height, weight and BMI showed no difference between both groups, also, ASA classification and duration of surgeries done showed no difference between the studied groups (P > 0.05). There were no recorded complications in both groups (P > 0.05). There was no significant difference among both groups regarding basal, and follow up period at 15 min values of heart rate, and basal value of mean arterial pressure (P > 0.05), but for the intraoperative hemodynamic parameters including MAP and HR, both parameters decreased significantly in the group which received dexmedetomidine in comparison to the other group except follow up values at 180 and 210 min, as no significant differences were recorded among both groups (P > 0.05). Regarding postoperative pain, the visual analogue score (VAS) was used to record it postoperatively every 2 hours while we found a statistically significant difference regarding the VAS from 4 to 6 hours postoperatively as P < 0.005, but, we found no difference regarding the postoperative total consumption of nalbuphine (P < 0.005) . As for patient satisfaction in the studied groups, an anaesthesia satisfaction questionnaire was developed, validated (Kappa coefficient). Dexmedetomidine group was associated with a significant increase in satisfaction compared to MG group (P < 0.05). Conclusion Magnesium sulphate and dexmedetomidine seem to be both effective adjuvants to bupivacaine in ESP blocks for postoperative analgesia in patients undergoing lumbar spine surgeries, with slightly better analgesia provided by dexmedetomidine.