The patient was placed in a flat position, and after successful anesthesia, the shoulders were padded and the head was elevated slightly laterally, and the towel was routinely disinfected and spread. A longitudinal oblique incision was made at the anterior border of the left sternocleidomastoid muscle, and the skin and the latissimus dorsi muscle were incised in turn. The position of the left common carotid artery was determined by palpation, and the sheath of the carotid artery was sharply separated and cut open, and the sides and posterior wall were bluntly separated to protect the left internal jugular vein and the left vagus and hypoglossal nerves. After local closure of the left carotid sinus with 2% lidocaine, the external carotid artery was isolated immediately adjacent to the root of the external carotid artery. Heparin 40mg was given intravenously, the brain was protected with an ice cap, and methylprednisolone was given intravenously, and the left common, internal and external carotid arteries were blocked sequentially. The end of the left common carotid artery was dissected from the beginning of the left internal carotid artery to the periphery of sclerosis, and the thickened intima was carefully separated and cut at the left common carotid artery with a stripper, slightly pulled and cut at the external carotid artery, and then dissected distally to the normal end of the left internal carotid artery, and the thickened intima was completely dissected, and the distal end of the intima was sutured and fixed to the epicardium. The dissection surface was flushed with heparin saline and the residual plaque and microscopic pieces were carefully removed to check that there was no floating endothelium, and the left carotid artery incision was sutured. The flow was opened in the following order: opening the left internal carotid artery after blocking, opening the left external carotid artery after blocking, then opening the left common carotid artery, and finally opening the left internal carotid artery. The left carotid artery incision was examined for suture without leakage and good pulsation of the internal carotid artery. Intravenously, 125 ml of 20% mannitol was given intravenously and the layers were sutured in turn. The instruments and dressings were counted correctly and then sutured in sequence. The operation was smooth and stable intraoperatively with little intraoperative bleeding, about 30 ml, and no blood transfusion.