Spinal arteriovenous fistulas supplied by branches of internal iliac artery: clinical features and endovascular treatment outcomes

PURPOSE: Branches of internal iliac artery (IIA) are under-recognized as potential feeders of spinal AVF and may be easily overlooked on spinal angiograms. This study aims to report clinical features and endovascular embolization outcomes in patients with spinal AVFs supplied by branches of IIA. METHODS: We reviewed medical records of 13 patients treated at our institution for spinal AVFs supplied by branches of IIA, focusing on clinical characteristics and procedural outcomes. In each instance, endovascular embolization was first-line therapy. RESULTS: Presenting symptoms included lower extremity weakness (n = 10), sensory impairment (n = 13), and sphincter dysfunction (n = 9). Spinal MRI regularly exposed perimedullary venous signal voids, although dilated draining veins of cauda equina showed prominence in eight patients only. On angiography, the precise location of the AVF was dural in nine and epidural in four patients, with fistula level ranging from L5 to S4. There was one instance of feeding vessel rupture, which was promptly controlled without sequelae. Ten patients (76.9%) experienced immediate AVF occlusions postembolization, but three lesions did recur. Single endovascular procedures ultimately resulted in stable occlusions for seven patients (53.8%). Together with subsequent surgical disconnections (n = 3), myelopathic symptoms abated in 10 patients overall. CONCLUSION: Angiography studies targeting suspected spinal AVFs should include IIA branches. In patients with spinal AVFs fed by branches of IIA, endovascular embolization represents a safe clinical option, offering 53.8% stable occlusion rate, and may be considered as initial choice of treatment in selected cases.