Intrathecal Dexmedetomidine and Acute Neuropathic Pain After Lower Limb Amputation

This randomized controlled trial evaluated the effect of adding intrathecal dexmedetomidine (10 µg) to hyperbaric bupivacaine (11 mg) for spinal anesthesia in patients undergoing lower limb amputation. Thirty patients (ASA I-III) scheduled for elective supra- or infracondylar amputation were randomly allocated to two groups: Control Group (n=15) received hyperbaric bupivacaine 11 mg plus saline 0.9%, and Experimental Group (n=15) received hyperbaric bupivacaine 11 mg plus dexmedetomidine 10 µg. Primary outcomes were duration of motor and sensory neuraxial block and postoperative analgesia at 48 hours. As a prespecified exploratory secondary outcome, incidence of acute neuropathic pain was assessed using the DN4 screening tool at 48 hours. The study was conducted at the Hospital Regional de Alta Especialidad Dr. Juan Graham Casasús, Villahermosa, Tabasco, Mexico, from 30 September to 15 December 2025. Ethics approval was obtained from the Institutional Review Board (CEI/JGC/C02-25) prior to patient enrollment.

Inclusion Criteria: * Patients scheduled for elective supra- or infracondylar lower limb amputation * Age 18 to 65 years * ASA physical status I-III * Acceptance of neuraxial anesthetic technique Exclusion Criteria: * Patient refusal of anesthetic procedure * Prolonged coagulation times * Anatomical abnormalities of the spine * ASA IV classification * Atrioventricular block grade 2 or 3 without pacemaker * Neurological deterioration (Glasgow score less than 8) * Hemodynamic instability