Sacral dural arteriovenous (DAVF) are rare presentations of vascular malformations in the spine. The majority of dural arteriovenous fistulae arise from the thoracolumbar levels, however sacral AV fistulae are rare1.
References:
1. Gilbertson JR, Miller GM, Goldman MS, et al. Spinal dural arteriovenous fistulas: MR and myelographic findings. AJNR Am J Neuroradiol 1995;16:2049–57.
We present a case of a 72 year old male with a 6 month history of progressive lower limb weakness with paraesthesia, lower back pain and bladder and bowel involvement. He had a T5 discectomy 3 months previously with no improvement in his symptoms. An initial magnetic resonance imaging (MRI) revealed a longitudinally extensive cord lesion. Cerebrospinal fluid was acellular with a raised protein of 1222 mg/L. A trial of intravenous steroids led to acute worsening of lower limb weakness.
Spinal MRI showed a longitudinally extensive hyperintensity from T5 to the conus. Magnetic resonance angiography (MRA) revealed serpiginous flow voids along the dorsum of the cord, most prominent from T9-12, likely representing a dural arteriovenous fistula. Spinal angiography showed a right sacral DAVF at the level of S5 supplied by the lateral sacral artery, which was successfully embolised. Clinically the patients motor weakness improved.
Sacral DAVFs are rare presentations of dural AV fistulas. Unless the iliac arteries and lateral sacral arteries are routinely examined during spinal angiography, they may be missed. DAVF should always be considered in the differential for a longitudinally extensive myelopathy.