Epidural vascular malformation demonstrated by epidural venography.

Abstract

A previously healthy 11-year-old boy complained of 3 days of discomfort in the left lumbar region, left buttock, and posterior thigh. He had had an upper respiratory infection forthe previous 2 weeks and had been fallen on by another player, without apparent injury, during a hockey game on the day pain began. The next day, his parents noted he was limping. Physical examination revealed a hyperlordotic lumbar spine with paraspinal muscle spasm and limitation of movement. A small dermal sinus was present in the natal cleft. Straight leg raising was limited to about 45#{176} bilaterally by back and buttock pain. There was mild motor weakness in the left leg for knee flexion and ankle dorsiflexion. Plantar flexion and hip extension were even weaker and the extensor hallucis longus could not overcome gravity. The left ankle jerk was slightly but consistently diminished. There were no sensory findings. Anal sphincter tone was normal and a normal anal reflex was present bilaterally. Lumbar myelography revealed no abnormality. Epidural yenography (fig. 1) demonstrated a collection of irregular, bizarre vessels projecting to the left of the theca at the L5 level. This was interpreted as a venous vascular malformation. The epidural venogram was otherwise normal. A laminectomy was carried out from L4 through 51 . The dermal sinus was excised to the level of the sacral hiatus. A large blue mass of blood vessels lay extradurally, on the left, between the axilla of the L5 nerve root and the shoulder of the 51 nerve root. The vessels continued distally around the L5 nerve root sleeve in circumferential fashion. An attempt to excise a portion of this mass of blood vessels between hemostatic clips was unsuccessful because of the confinement of space and copious bleeding. A sinusoidal vessel in continuity with this collection of vessels ran down into the L5 vertebral body. The abnormal blood vessels were excised with the aid of the bipolar cautery and the sinus opening into the vertebral body was occluded with bone wax. Further bone removal was carried out at both foraminal levels and both root sleeves were inspected to ensure that there was no residual compression. Postoperatively, there was a steady regression of the patient’s signs and symptoms. Motor power had returned to virtually normal in all muscle groups 20 months after surgery and there were no other neurologic abnormalities. Epidural venography has been used increasingly to complement and, in some cases, to obviate myelography, particularly in the assessment of L5-S1 disc disease where a large space frequently exists between the backs of the vertebral bodies and the anterior limit of the spinal subarachnoid space. Venography is also more sensitive than myelography in cases of posterolateral disc herniations in the presence of a narrow transverse diameter of the subarachnoid space. Our case had an epidural vascular malformation producing a mass effect on the L5 and Si nerve roots, clinically simulating