Teaching NeuroImage: Foramen Magnum Dural Arteriovenous Fistula Presenting With Thoracolumbar Myelopathy

A 71-year-old man presented with a 3-year history of weakness and numbness in his lower limbs. Neurologic examination revealed decreased muscle strength in both lower limbs (grade 3), decreased sensation below T8, and bowel and urine dysfunction. No specific treatment had been given. Spinal MRI showed cervical flow voids and vessel enhancement and thoracolumbar spinal cord edema. Spinal angiography was negative, and cerebral digital subtraction angiography/computer tomography angiography revealed a foramen magnum dural arteriovenous fistula (FMDAVF; Figure 1). Surgical disconnection is a universally curative and frontline treatment of craniocervical junction (CCJ) arteriovenous fistulas (AVFs).¹ The fistula was successfully removed by microsurgical clipping (Figure 2), and the postoperative symptoms gradually improved.

FMDAVF is a type of CCJ AVF; however, presenting with thoracolumbar myelopathy without cervical involvement is extremely rare.^1,2 Owing to the higher rates of treatment failure and procedural complications than thoracic and subaxial cervical lesions, microsurgical treatment is particularly preferred for CCJ AVFs.¹