Spinal Bupivacaine-Dexmedetomidine versus Bupivacaine-Fentanyl for lower Limb Amputation Surgery. Effects on Early Stump and Phantom Pain

Background: in neuroaxial anesthesia, there was many adjuvants used with the purpose of increasing anesthesia duration and reduction of postoperative analgesia. Objective: comparison between dexmedetomidine and fentanyl when added to 0.5% hyperbaric bupivacaine, for lower limb amputation on early stump and phantom pain after spinal anaesthesia. Patients and Methods: Ninety patient arranged for lower limb amputation surgery were randomly allocated into three groups (each 30 patients). Each patient received 2 ml of hyperbaric bupivacaine (0.5%) plus 0.5 ml normal saline in control group (Group B) or 5µ dexmedetomidine diluted in 0.5 ml normal saline in BD group or 25 µ fentanyl diluted in 0.5 ml normal saline in BF group. Anesthesia, analgesia, sedation, hemodynamic changes, adverse effects and post-operative pain up to one month were recorded. Results: The studied groups showed no significant differences regarding demographic characteristics and hemodynamic (heart rate and mean arterial pressure). Patients in group BD had significant increase of sensory and motor block time compared to BF B groups. Post-operatively, there was a significant decrease of pain in BD group in the first 24 hours when compared to control or BF group. The postoperative mean total consumption of analgesics during the first day was significantly decreased in BD when compared to BF and control groups. Conclusions: dexmedetomidine (5μg) represents a good alternative to fentanyl (25μg) as a spinal adjuvant to bupivacaine in surgery for the lower limb.