Surgical management of angiographically occult spinal dural arteriovenous fistulae (type I spinal arteriovenous malformations): Three technical case reports

OBJECTIVE AND IMPORTANCE: Spinal dural arteriovenous fistulae (Type I spinal arteriovenous malformations [AVMs]) have been recognized as a treatable cause of progressive myelopathy. The diagnosis and characterization of these lesions rest heavily on spinal angiography. CLINICAL PRESENTATION: We present three patients whose clinical presentations were consistent with a spinal dural AVM but whose spinal angiographic results were negative. INTERVENTION: The surgical treatment of these angiographically occult spinal AVMs is described. In retrospect, in each case, the feeding vessel to the AVM was injected but not seen. CONCLUSION: Some spinal dural arteriovenous fistulae will be angio-graphically occult. If the clinical and radiographic presentations strongly suggest the presence of an arteriovenous fistula, surgical exploration should be considered.