Mirror-image spinal dural arteriovenous fistulas at the craniocervical junction: case report and review of the literature.

Background and Importance: We report an extremely rare case with mirror-site spinal dural arteriovenous fistulas (DAVFs) at the craniocervical junction. Although multiple spinal DAVFs have been reported in the literature, complete mirror-site lesions with fistulas and feeding arteries in the symmetric position have not been previously described.
Clinical Presentation: A 74-year-old man presented with walking disturbance, urinary incontinence, and constipation progressing over a 14-month period. T2-weighted magnetic resonance imaging showed a high-intensity area in the spinal cord at the level from C4 to C6 and multiple flow voids at the surface of the spinal cord. Three-dimensional computed tomographic angiography revealed bilateral DAVFs located in the mirror site of the craniocervical junction. Direct surgery with suboccipital craniectomy and C1 laminectomy revealed dilated tortuous red veins on the dorsal surface of the spinal cord. We found bilateral symmetric red veins around the dural penetration of the vertebral artery. Both red veins were successfully interrupted with the aneurysmal clips. Postoperative 3-dimensional computed tomographic angiography revealed a disappearance of the bilateral fistulas. Magnetic resonance images obtained 6 months after the surgery confirmed the disappearance of the intramedullary high-intensity area and flow voids. The symptoms before the operation improved after surgery, especially urinary incontinence and constipation, with slight walking disturbance.
Conclusion: Because fistulas in the present case existed at the same spinal level, we found multiple fistulas on the first examination. This early notification resulted in a good outcome from the first operation. If patients with spinal DAVFs have rapidly progressing symptoms, one should suspect multiple fistulas.