A case of cervical myelopathy due to dural arteriovenous fistula at the craniocervical junction

A 70-year-old woman noted paresthesia ascending from both legs to her thighs 27 months previously. She also suffered from urinary urgency and incontinence. Thereafter, weakness in both legs developed and gradually became worse. At the time of admission, a neurological examination revealed diffuse atrophy and mild spasticity in all four extremities, bilateral mild weakness in both upper extremities, and severe weakness in both lower extremities. Her superficial sensation was moderately impaired below the Th 3 level on her right side, and below the Th 4 level on her left side along with a mildly decreased sense of vibration in her left leg. Marked hyperreflexia in all four extremities and bilateral pathological reflexes were also observed. Pollakisurea, urinary incontinence and constipation were also present. Cervical MRI showed a swelling of the spinal cord at the C3 to C7 levels. Inside the spinal cord, low signal intensity lesions were seen on the T ₁-weighted MRI, and high signal intensity lesions were observed on the T ₂- weighted MRI, and the rim of the cervical cord was also enhanced by gadolinium-DTPA. MR angiography revealed enlarged and tortuous vessels at the craniocervical junction, thus suggesting the presence of a dural arteriovenous fistula (AVF). Vertebral arteriography demonstrated abnormal vessels at the spinomedullary junction supplied by the right vertebral artery, which drained into the anterior and posterior spinal veins. After surgically treating the dural AVF, the swelling of the spinal cord, the abnormal signals on MRI, and the clinical symptoms all markedly improved. Although most of the spinal dural AVF were located at the thoracic and lumbar levels, the present case was considered to be a very rare case of dural AVF, since it was located at the craniocervical junction and thus led to the development of cervical myelopathy.