Spinal Arteriovenous Fistulas of the Filum Terminale: Case Report and Literature Review

Spiinal arteriovenous fistulae (AVF) are an uncommon cause of myelopathy that require a high degree of suspicion to diagnose. Treatment strategies have not yet been established. Only a few cases of AVFs of the filum terminale (FT) have been reported. In this review, we describe clinical presentation, imaging, and treatment options for this rare type of spinal AV shunt. A 43-year-old male patient presented with progressive low back pain and paraparesis with gradually worsening bilateral foot paresthesias and sphincter dysfunction. He underwent magnetic resonance imaging, which revealed a hypersignal in the thoracolumbar cord and angiography diagnosed a microfistula of the FT. Surgery was preferred over endovascular treatment and we realized an L5 laminectomy to open the dura mater and found a hypertrophic FT. After identifying the fistula which was closely related to cauda equina, and dissecting the root from the fistula, a permanent clip was placed on the proximal part of the arterialized vein. Surgery was uneventful, and 6 months postoperatively, the patient has fully recovered. FT AVFs although rare should be considered as a differential diagnosis of progressive paraparesis, and successful surgery through clipping relies on the angioarchitecture of the shunt and the clinical manifestations of the patient.