Disclosures: Vincent J. Yaccarino, MD: No financial relationships or conflicts of interest

Case Diagnosis: A 65-year-old female with low back pain and progressive neurological deficits due to conus medullaris syndrome from a dural AV fistula.

Case Description or Program Description: The patient presented to spine clinic with a several month history of low back pain radiating into the left lower extremity, progressively worsening bilateral lower extremity numbness and weakness, frequent falls, and bowel and bladder incontinence.

Setting: Tertiary Care Hospital

Assessment/Results: A lumbar MRI showed an abnormal appearing distal spinal cord and conus medullaris with increased caliber and internal edema. Several surrounding vascular flow voids were seen. These imaging findings suggested a dural AV fistula and the patient was referred to neurosurgery. A detailed MRI with MRA time-resolved imaging of contrast kinetics imaging of the thoracic and lumbar spine and a spinal angiogram redemonstrated a type I dural AV fistula spanning from T5 through the conus medullaris with associated cord edema. The source seemed to be from prominent intercostal arteries at T8. She has an upcoming scheduled embolization procedure.

Discussion (relevance): Spinal dural AV fistulas are a rare clinical entity that can cause significant morbidity. This incidence is estimated at 5-10/million/year and is most common in older men (1). They are the most common vascular malformation in the spinal cord. The increase in spinal venous pressure leads to impaired drainage of spinal veins, subsequent venous congestion of the cord causing progressive myelopathy. Diagnosis is made via MRI which shows characteristic findings of cord edema, perimedullary vessel dilation and cord enhancement. Treatment is occlusion the shunting zone, either with embolization or neurosurgical approach. Once the fistula is occluded, improvement of symptoms are typically seen (2).

Conclusions: Dural AV fistulas should be on the differential with any progressive myelopathic presentation. Despite being the most common spinal vascular malformation, the presenting symptoms are often nonspecific. Without treatment, the progressive myelopathy can lead to significant morbidity.

Level of Evidence: Level IV

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/conus-medullaris-syndrome-due-to-dural-av-fistula-a-case-report/