Spinal epidural arteriovenous fistula with late onset perimedullary venous hypertension after lumbar surgery: case report and discussion of the pathophysiology.

Abstract

Case report and literature review. Spinal epidural arteriovenous fistulas with secondary reflux into the perimedullary veins are rare. We report a patient who presented with delayed progressive congestive myelopathy after lumbar surgery. The pathophysiology and the anatomic basis for the responsible arteriovenous fistula are discussed. Delayed neurological deterioration after spinal surgery is uncommon. Epidural fistulae uncommonly may become symptomatic from an epidural hematoma, mass effect from distended veins, and rarely from a spinal dural arteriovenous fistula. We report on a patient with delayed progressive congestive myelopathy after lumbar surgery, and discuss the pathophysiology and the anatomical basis for the causative fistula. A 68-year-old man presented with progressive lower extremity weakness and sensory decrease, and loss of sphincter control 2 years after unilateral lumbar laminectomy and fusion for a disc herniation. MRI showed diffuse new cord edema and intradural perimedullary dilated vessels. Spinal angiography revealed an epidural arteriovenous fistula at the site of the previous laminectomy, with intradural perimedullary venous drainage. The fistula was successfully treated surgically and the patient experienced rapid and gradual neurologic improvement, being able to walk without a cane within 6 weeks of repair. There are few causes of delayed neurologic deterioration after lumbar spinal surgery. Epidural fistulas are uncommon and rarely symptomatic, and when they are, it is usually from an epidural hematoma or mass effect from distended epidural veins. Epidural may rarely result in spinal dural arteriovenous fistulas, the most common spontaneous spinal arteriovenous condition, causing a congestive myelopathy characterized by lower extremity spasticity, sensory changes, and loss of sphincter control. Delayed neurologic deterioration after spinal surgery is uncommon. Epidural arteriovenous fistulas with secondary intradural drainage, which are rare, should be considered.