Study design: Retrospective consecutive case series.
Objective: To assess the symptoms, neurologic signs, and radiologic findings in a large series of patients with myelopathy due to spinal dural arteriovenous fistula (SDAVF).
Summary of background: The clinical diagnosis of SDAVF is difficult because presenting symptoms and signs can be similar to those seen with spinal canal stenosis or peripheral nerve or root disorders.
Methods: We reviewed 153 consecutive patients with SDAVF treated surgically at our institution between 1985 and 2008. Before surgery, all patients had detailed neurologic examination, 147 patients had spinal magnetic resonance imaging (MRI) and all but one, had spinal angiography. We evaluated associations between symptoms, physical signs, spinal cord T2 signal abnormality on MRI, and fistula level on angiogram.
Results: Mean age was 63.5 years and 119 (77.8%) were men. Weakness and sensory changes are usually symmetric and ascend from the lower extremities. Presenting symptoms included leg weakness (74 patients, 48.4%), leg sensory disturbances (41 patients, 26.8%), pain involving back or legs (31 patients, 20.3%), and sphincter disturbances (6 patients, 3.9%). Worsening weakness with exertion was present in 66 (43.1%) patients and correlated with thoracic fistula location (P=0.04). Pinprick level was identified in 57 (37.3%) patients; L1 level (22.8%) was the most common, followed by T10 (19.3%). Fistula level (±2 levels) corresponded to pinprick level in only 40% of these patients. T2 signal abnormality involved the conus in 95% of our patients. Highest cord level of T2 signal hyperintensity (±2 levels) corresponded to pinprick level in 25% of cases.
Conclusion: Leg weakness exacerbated by exercise, likely due to worsening hypertension in the arterialized draining vein, is a common manifestation of thoracic SDAVF. Although a sensory level is often found, it cannot reliably guide the level of imaging. Thus, the entire spine should be examined with MRI when an SDAVF is suspected.