Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 51, Num. 3, 2003, pp. 390-391

Neurology India, Vol. 51, No. 3, July, 2003, pp. 390-391

Delayed post-surgical development of dural arteriovenous fistula after cervical meningocele repair

Flannery T, Tan MH, Flynn P, Choudhari KA
Department of Neurosurgery, The Royal Victoria Hospital, Grosvenor Road, Belfast BT12 6BA,

Correspondence Address:
Department of Neurosurgery, The Royal Victoria Hospital, Belfast BT12 6BA
kchoudhari@hotmail.com

Code Number: ni03126

ABSTRACT

A 34-year-old female patient presented with an intracranial subarachnoid hemorrhage and was found to have a dural arteriovenous fistula at the site of previous cervical meningocele repair. Subsequent occlusion was achieved with endovascular embolization. To our knowledge, the phenomenon of the development of a spinal dural fistula at the site of a meningocele repair has not been recorded before.

INTRODUCTION

A spinal dural arteriovenous fistula (SDAVF) is a direct communication of artery to vein located at the dural covering of the spinal nerve root.[1] There is usually a single artery or rarely, multiple feeding arteries connected to a single radicular vein, which then drains to the perimedullary veins.[2] Patients usually present with myelopathic symptoms which are thought to arise secondary to venous hypertension and hypoperfusion of the spinal cord.[3] Rarely, SDAVFs may present with subarachnoid hemorrhage.[4],[5] We report a case of a patient who had a cervical meningocele repair as an infant and presented with subarachnoid hemorrhage secondary to a cervical SDAVF thirty-three years later.

CASE REPORT

A 34-year-old female with a previous history of a cervical meningocele repaired at the first two cervical levels (C1-2) as an infant, was admitted with a sudden onset of occipital headache, loss of consciousness lasting 15 minutes, vomiting and an episode of urinary incontinence. On clinical examination, she was conscious, alert, orientated with neck stiffness. She was also noted to have a scar at the back of her neck, which was subsequently found to be the site of her cervical meningocele repair in infancy. A computerized tomography (CT) scan of the brain revealed subarachnoid hemorrhage with intraventricular extension. There was associated ventriculomegaly but it was felt to represent chronic arrested hydrocephalus. Transfemoral four-vessel cerebral angiography revealed a small extracranial arteriovenous fistula in the midline at the level of the spinous process of the first cervical vertebra (C1) [Figure-1].

It was supplied by the cervical branches of the right and left vertebral arteries. Three days later, she underwent endovascular embolization of the arteriovenous malformation (AVM) with cyanoacrylate glue. The feeding branch from the left vertebral artery was successfully obliterated while the right could only be partially embolized [Figure-2]. However, almost complete obliteration of the fistula was achieved. The patient tolerated the procedure well and was discharged without neurological deficits.

DISCUSSION

SDAVFs, the most common spinal AVMs, are being increasingly recognized since the advent of superselective spinal angiography.[6] The typical angiogram appearance is that of a slow-flow arteriovenous fistula in the neural foramen draining through dilated tortuous perimedullary veins located on the surface of the spinal cord.[2] They are thought to develop following venous thrombosis of the intradural spinal veins.[4] Most SDAVFs are located in the thoracic and lumbar regions while those arising in the cervical region account for a small percentage of cases.[4] Those in the cervical spine can be fed by the branches of either the thyrocervical and costocervical trunk and/or both vertebral arteries.[7]

While spinal AVMs have been reported to occur in association with meningomyelocele,[8] no fistulous communication was evident at the time of the initial surgery in this case. Although it is possible that the occurrence of a SDAVF at the site of previous cervical meningomyelocele repair is purely coincidental, the development of dural arteriovenous fistulae following previous trauma and surgery is well reported.[9],[10],[11],[12] Postoperative fibrosis may have accounted for impaired drainage of the dural venous plexus with consequent venous thrombosis of the intradural spinal veins. There is widespread agreement that thrombosis of the intradural draining veins is responsible for SDAVF formation.[13] While the origin of this patient's hemorrhage is unclear, it is possible that venous hypertension in the arterialized vein and the draining perimedullary veins may have precipitated rupture and venous hemorrhage.[14]

Although spinal vascular malformations represent less than 4% of all spinal cord masses, they are important clinical entities because they produce considerable morbidity and may even be fatal if left untreated.[15] The mortality rate associated with spinal subarachnoid hemorrhage caused by spinal vascular malformations is up to 20%.[15] Treatment of a SDAVF consists of obliteration of the artery-to-vein communication, which can be done by surgical intervention or by an embolization procedure. Embolization of SDAVFs is associated with a 60 to 90% obliteration rate; the recurrence or recanalization rate may be higher with certain agents, such as polyvinyl alcohol, than with acrylic glues.[16] Surgical ligation is often reserved for cases with embolization failure or in case of inability to safely embolize the lesion.[17]

Though spinal AVMs are known to occur in association with meningomyelocele, most SDAVFs are thought to be acquired through venous thrombosis of intradural spinal veins. We believe this is the first reported case of the development of a cervical SDAVF in a patient who previously had a cervical meningocele repair. The possible significance of previous surgery at the craniocervical junction, in a patient presenting with intracranial subarachnoid hemorrhage, needs to be highlighted. It should also be pointed out that embolization may not provide a long-term cure. Recurrence of this condition is possible and may necessitate surgical exploration. As such, long-term follow-up of the patient is recommended.

REFERENCES

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