Unilateral lower extremity paralysis after coil embolization of an internal iliac artery aneurysm.

Neurologic complications after treatment of internal iliac artery (IIA) aneurysms are rare, especially if confined to one IIA. We report a patient in whom profound right lower extremity paresis developed after unilateral right IIA coil embolization for treatment of a 4-cm IIA aneurysm, despite the presence of a patent contralateral IIA. This case illustrates the important, yet unpredictable, nature of pelvic blood flow to the distal spinal cord and lumbosacral plexus and the unpredictable consequence of IIA occlusion.