Letter to the Editor

Lumbar disc herniation exacerbating venous hypertension from a spinal perimedullary arteriovenous fistula of the filum terminale

Fistulas of the filum terminale are rare lesions that result from a fistulous connection between the artery and vein of the filum terminale. These lesions often present as progressive thoracic myelopathy secondary to venous hypertension that is transmitted to the coronal venous plexus of the spinal cord. Frequently, filum fistulas will be associated with lumbar stenosis and likely form as a result of chronic inflammation and compression. However, owing to the relative rarity of filum fistulas and the commonality of lumbar stenosis, the presence of a filum fistula could be overlooked or misdiagnosed.

We have presented the case of a 62-year-old man with severe lumbar stenosis who had presented with progressive thoracic myelopathy. The evaluation, including spinal angiography, identified a low-flow arteriovenous fistula within the filum terminale that was successfully treated with microsurgical obliteration. The patient tolerated the procedure well, with good functional recovery within 1 month.

Just as was the case with our patient, these lesions demonstrate a high association with lumbar stenosis and tethered or tight cord syndrome. We reviewed the clinical presentation, imaging findings, surgical management, and possible mechanisms of development for these rarely encountered fistulas.