SPINAL DURAL ARTERIOVENOUS FISTULA - A RARE AND UNDERDIAGNOSED DISEASE
Background: A spinal dural arteriovenous fistula (SDAVF) is an abnormal shunt between a spinal radicular artery and corresponding radicular vein that drains the perimedullary venous system.
Methods: Between August 2012 and January 2013 we diagnosticated 3 patients with SDAVF. They were treated by surgery.The diagnosis of SDAVF was confirmed by MR-angiography which reveals “flow- void phenomena”, representing tortuous and dilated veins at the dorsal surface of the spinal cord.
Results: Case 1- A 57-year old female, M.B, acute onset; the symptoms develop within minutes and mimic an anterior artery syndrome: paraplegia, total sensory loss, urinary retention, bowel incontinence.MRA: on T2 weighted sequences the cord edema is depicted as a centromedullary hyperintensity over T7-L1; T2 weighted MRA shows numerous “flow-voids” over the dorsal spinal cord, between T10-L1.
Case 2- A 35-year old female, S.F., subacut onset in two weeks with gait difficulties, asymmetrical paraparesis and sensory symptoms;, first with loss of pain and temperature sensation, ascending to the T6 level; micturition disturbances. MRA: hipointensities on T1-weighted images and hyperintensities on T2-weighted images (spinal cord edema and perimedullary vessels which are dilated and coiled at T6-T11).The technique of first pass gadolinium-enhanced MRA demonstrate the level of the shunt at T6.
Case 3-A 71-year old male, H.I, chronic onset in 3 months presented initial symptoms like difficulty in climbing stairs, gait disturbances, paresthesias and radicular pain witch affect both lower limbs; later the patient was paraplegic with loss of all modalities of skin sensation below T2; urinary retention and constipation. MRA: abnormal blood vessels on either the ventral and the dorsal side of the spinal cord below T2.
- Patients develop a progressive myelopathy which at the early stages of the disease often mimics a polyradiculopathy or anterior horn cell disorder.By the time involvement of upper motoneurons or sacral segments makes the diagnosis of SDAVF inescapable, patients suffer from considerable neurological deficits.
- Surgical treatment aimed at closure the fistula. Embolization of SDAVF is not possible in our clinics.
- Significant subjective improvement was noted in walking and muscle power after surgical treatment.