We report the case of a patient who developed paraparesis 2 days after endovascular aneurysm repair for a right common iliac aneurysm. The patient had undergone thoracic endovascular aortic repair. The left subclavian artery was occluded, but the left internal iliac artery was preserved. The patient fully recovered from the paralysis within 3 months. This case illustrates the importance of collateral blood supply to the spinal cord from the lumbosacral region, especially when other sources are occluded.