Cauda equina syndrome after spinal anaesthesia in a patient with severe vascular disease

Spinal anaesthesia is selected for many lower extremity surgical procedures each year in the United States with a high degree of safety and efficacy. Even when adverse neurological outcomes have occurred, anatomical abnormality or coagulopathy have been implicated in the majority of cases. Epinephrine is used in high concentrations in many of these anaesthetics to increase the duration and intensity of the block. Although epinephrine is known to decrease spinal cord blood flow, its use in normal patients has not caused complications. We report a case where spinal anaesthesia with bupivacaine and epinephrine resulted in anterior spinal artery compromise and the development of a cauda equina syndrome postoperatively. A 57-yr-old man with severe coronary artery and peripheral vascular disease was scheduled for incision and drain of an abscess of the left thigh. He received an atraumatic dural puncture and injection of 12.5 mg bupivacaine with 0.2 ml 1:1000 epinephrine. During onset, he experienced a severe, painful sensation of the thighs which resolved with development of the block. Postoperatively, he was noted to have exacerbation of proximal muscle weakness and decreased perineal sensation and rectal tone. Subsequent EMG studies demonstrated proximal neuron loss consistent with cauda equina syndrome, presumed to be related to insufficiency of the anterior spinal artery. Routine use of epinephrine in spinal anaesthesia for patients with multi-organ vascular disease should be considered carefully because of the possibility of vascular insufficiency of the spinal cord which would be exaggerated by the vasoconstrictive effect of epinephrine.