Microsurgical interruption of dural arteriovenous fistula at the foramen magnum.

We report two rare cases of progressive congestive myelopathy caused by dural arteriovenous fistulae (DAVF) at the foramen magnum. The first, a 69-year-old male with a 2-year history of progressive myelopathy, had symptoms unrecognized due to a past history that included spinal caries and congenital dislocation of the hip. The second, a 60-year-old male, had a recurrence of the myelopathy three months after endovascular occlusion of the DAVF feeding artery. Both patients were successfully treated by direct microsurgical interruption of the arterialized medullary vein with functional and radiological improvement. The clinical manifestations of DAVF at the foramen magnum are nonspecific, mimicking those of cervical spondylotic myelopathy or cervical neoplasm. Accurate and early diagnosis followed by complete obliteration of the fistula is mandatory to avoid permanent neurological deficit.