Ischemic paralysis caused by internal iliac artery embolism after endovascular recanalization for lower extremity arteriosclerosis obliterans: a case report

BACKGROUND: Lower extremity paralysis is a devastating complication after endovascular therapy for lower extremity arteriosclerosis obliterans (LEAOD). Common mechanisms include ischemia-reperfusion injury, acute arterial embolism, and thrombosis. Paralysis caused by internal iliac artery embolism is exceptionally rare and may be overlooked when postoperative neurologic deficits are initially attributed to spinal or cerebral causes. CASE PRESENTATION: An 86-year-old man developed recurrent bilateral intermittent claudication 3 years after endovascular treatment for LEAOD, followed by right toe ulceration. Preoperative computed tomographic angiography showed severe multilevel stenosis and in-stent reocclusion in both lower limbs. He underwent bilateral thrombus aspiration, balloon angioplasty, and catheter-directed thrombolysis. One hour after the procedure, acute left lower limb weakness (muscle strength grade 0-1) and hypoesthesia below the mid-calf occurred. Emergency abdominal-pelvic non-contrast CT, lumbar spine MRI, brain imaging, and lower limb CTA excluded lumbar canal disease and stroke, while suggesting new internal iliac artery occlusion. Emergency thrombus aspiration and balloon angioplasty of the left internal iliac artery restored substantial patency and improved muscle strength to grade III-IV in the thigh and grade III in the leg. Because pain persisted and distal perfusion remained insufficient, femoral endarterectomy and infrapopliteal balloon angioplasty were subsequently performed. After 1 month of rehabilitation, muscle strength remained grade III, with persistent sensory impairment and assisted ambulation. CONCLUSIONS: Internal iliac artery embolism is a rare but clinically important cause of ischemic paralysis after peripheral endovascular intervention. In patients with extensive multilevel occlusive disease, preoperative assessment of internal iliac collateral perfusion and cautious staged procedural planning may reduce risk. Sudden postoperative limb paralysis should prompt urgent spinal and vascular imaging, followed by timely revascularization when ischemia is suspected.