Year : 2002 | Volume
: 12 | Issue : 1 | Page : 71--73
Imaging and intervention of an uncommon case of spinal dural arteriovenous fistula supplied by lateral sacral artery
CJ Rao, S Budihal, SL Reddy
Department of Consultant Radiologist, Apollo Hospital, Hyderabad, India
C J Rao
Department of Consultant Radiologist, Apollo Hospital, Hyderabad
|How to cite this article:|
Rao C J, Budihal S, Reddy S L. Imaging and intervention of an uncommon case of spinal dural arteriovenous fistula supplied by lateral sacral artery.Indian J Radiol Imaging 2002;12:71-73
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Rao C J, Budihal S, Reddy S L. Imaging and intervention of an uncommon case of spinal dural arteriovenous fistula supplied by lateral sacral artery. Indian J Radiol Imaging [serial online] 2002 [cited 2020 Feb 24 ];12:71-73
Available from: http://www.ijri.org/text.asp?2002/12/1/71/28420
Spinal dural arterio-venous fistulas (AVF) are abnormal arterio-venous communications on the surface of the dura. They are supplied by the branches of the vertebral, intercostals, lumbar, middle sacral or subclavian arteries and rarely by the branches of the internal iliac artery. We present a case of spinal dural AVF supplied by the lateral sacral branch of the left internal iliac artery. The importance of performing the internal iliac arteriogram in a suspected case of dural AVF is highlighted.
A forty-year-old male presented to the neurosurgical department with progressive weakness of both lower limbs, right more than the left, for the last 3 months. Inability to walk on his own was present for the last 15 days. There was no numbness or tingling sensation. Frequency of micturition was present for the last 10 days. There were no bowel symptoms.
Central nervous system examination revealed normal higher mental functions and cranial nerves. Motor System evaluation showed increased tone in both lower limbs, right more than left, with decreased sensation from L1 dermatome level.
The patient was referred for an MRI Scan of the dorso-lumbar spine to look for a space occupying lesion. MRI demonstrated mildly hyperintense conus on T2 weighted imaging and showed multiple curvilinear flow voids in the cauda equina extending from L1 to L3. There was a large dilated perimedullary vein noted extending in the anterior part of the dural sac [Figure 1]. Contrast enhanced studies showed enhancement of the flow voids as well as conus [Figure 2].
An imaging diagnosis of intra-spinal vascular malformation was made with enhancement in the conus attributed to ischaemia secondary to venous hypertension.
Spinal angiography was performed by selective catherization of the intercostals and the lumbar arteries which did not reveal any feeders to the vascular malformation. However selective internal iliac arteriogram from the left side showed a large feeder from the lateral sacral artery with venous drainage into dilated radicular and perimedullary veins [Figure 3],[Figure 4]. There was evidence of two venous aneurysms in the draining vein. Subselective catherization was performed using coaxial micro catheter and particulate embolic material (Ivalon - 500-700 microns-target therapeutics) was used to embolize the fistula. Post embolisation angiogram showed obliteration of the dural fistula [Figure 5].
Vascular malformations of the spine are broadly classified into four subgroups - spinal dural AVF, spinal cord AVF, spinal cord AVM and cavernous angiomas of the cord . Spinal dural AVF's are the commonest among them . The arterial supply is usually from the dural branches of the dorsal spinal artery with venous drainage into the dilated radicular and perimedullary veins. These patients present with a slowly progressive myelopathy and if untreated can progress to complete quadriparesis or paraplegia ,. The site of the fistula is most commonly in the thoracic and lumbar regions and rarely in the cervical region ,. The fistula is located on the dural surface close to the feeding artery pedicle. The resultant venous hypertension produced by the fistula can produce symptoms far remote from the nidus of the fistula. The intercostals and lumbar arteries supply most fistulas. However arterial branches from the thyrocervical, costocervical, pre sacral, external carotid and vertebral arteries have been reported. Rarely fistulas located in the sacral region, are supplied by lateral sacral or iliolumbar arteries ,.
MR imaging shows abnormal T2 hyperintensities of the cord, focal cord enhancement and/or enlarged draining veins . In our case the intercostals and lumbar arteries were catherized and did not reveal any fistula. Left internal iliac arteriogram showed mildly enlarged lateral sacral artery feeding the dural AVF at the level of S1 with a tortuous draining vein extending upto D11 in the posterior aspect of the dural sac.
Treatment of dural fistulas is either by means of surgery or by endovascular embolisation, both of which are equally effective. The endovascular treatment is by embolization which can be done by using IBCA (glue) or particulate material. It was observed that the rate of recanalization of spinal dural AVF is high when particulate material was used as the embolic agent.
Incidence of spinal dural AVF in the sacral region is quite rare. MRI may indicate the diagnosis, but the final test of choice is digital subtraction arteriogram. Complete spinal arteriographic evaluation should include the internal iliac arteries to identify a fistula in the sacral region, when other levels have failed to demonstrate the lesion.
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