Transforaminal epidural steroid injection and paraplegia: case report and bibliographic review]

OBJECTIVES: We report a patient in whom paraplegia developed following transforaminal epidural injection of a corticosteroid and discuss the physiopathology of this complication, based on a literature survey. CASE REPORT: A 40-year-old man presented with low-back pain and symptoms of L4 radiculopathy due to degenerative disc herniation resistant to conventional medical treatment. Computed tomography revealed posterolateral L4-L5 disc protrusion. A dosage of 125 mg of hydrocortisone was given by epidural transforaminal L4-L5 left injection under radioscopy guidance. Within minutes following the injection, intense pain developed in both legs, with T12 complete paraplegia. Emergency magnetic resonance imaging (MRI) 2 hours later did not reveal spinal cord abnormalities. The patient underwent immediate surgery consisting of excising the protruding disc and extensive L3-L5 laminectomy. MRI performed 3 months later did not reveal medullar abnormalities. Six months later, the patient continued to show slow neurologic improvement, permitting him to walk with crutches and to stop intermittent self-catheterisation. DISCUSSION: The occurrence of paraplegia following epidural transforaminal injection of corticosteroids is a rare complication. To our knowledge, only 5 similar cases have been described. Most of the authors proposed that the mechanism of this complication is ischemia of the terminal cone due to accidental suppression of medullary blood supply. Direct lesion of a medullar artery, arterial spasm, or corticosteroid-induced occlusion due to undetected intra-arterial injection could lead to this medullar infarction. Anatomical variations of the path followed by the Adamkievicz artery strongly support this hypothesis.