1426 - A case report of a spinal dural arteriovenous fistula

Case Diagnosis: Spinal Dural Arteriovenous Fistula (SDAVF)

Case Description: A 67-year-old male presented to clinic with new progressive right-sided low back pain and leg pain.  Imaging showed severe spinal canal stenosis at L4-5 with grade 1 anterolisthesis, severe right foraminal stenosis at L4-5, and a subtle T2/STIR signal hyperintensity from T9 to conus. Epidural steroid injections provided some relief, but within 2 months he developed lower extremity weakness and subsequently underwent a L4-5 decompression. A month later with minimal improvement, he had a revision of the decompression and fusion. Patient again had limited improvement, now with intractable back pain. Repeat thoracolumbar spine MRI showed progressed signal in the central cord from T3 to conus. Spinal angiogram (DSA) confirmed a SDAVF. Ligation of the SDAVF resolved the back pain and patient had improved strength on exam.

Discussions: SDAVFs are a rare and underdiagnosed disease process, presenting insidiously later in life with non-specific symptoms including sensory deficits, weakness, and bladder disturbances. Often mimicking more common diagnoses, such as degenerative disc disease, spinal stenosis, myelitis, and multiple sclerosis, leading to delays in treatment. Left untreated, roughly half will develop permanent disability within 3 years of symptom onset. Initial MRIs may show cord edema but can be extremely subtle. Even after SDAVF is suspected, spinal DSA, considered the gold standard for confirmation, may provide false negatives, requiring repeat DSA.

Conclusions: Clinicians should include SDAVF in their differentials for patients over 50 years-old presenting with progressive nonspecific neurological symptoms, especially in the lower extremities. Workup should be thorough and may include multiple diagnostic tests. A timely diagnosis is essential for proper treatment and prevention of irreversible spinal damage. Treatment involves some combination of endovascular embolization and surgical occlusion that are safe and simple with high success rates.