[A case of a surgically treated extracranial internal carotid artery saccular aneurysm].

Extracranial internal carotid artery aneurysm is rare. Most cases are due to spontaneous or traumatic dissection of the cervical internal carotid artery. Here we report a case of surgically treated extracranial internal carotid artery (ICA) aneurysm. A 74-year-old man noticed a pulsatile mass just below the left mandibular angle. Intravenous digital subtraction angiography revealed multiple aneurysms in the systemic arteries, including the aortic arch, abdominal aorta and left extracranial ICA. It was decided to treat the aneurysms of the aortic arch and of the abdominal aorta conservatively. Cerebral angiography, however, showed a saccular aneurysm which projected latero-posteriorly at the C2 level of the left extracranial ICA. Although the patient had no previous ischemic event, we decided to treat this aneurysm surgically in view of the risk of cerebral ischemia caused by intraaneurysmal thrombus formation or rupture of the aneurysm by neck injury. The operation was performed under mild hypothermal general anesthesia. Electroencephalography was carried out during the operation. A skin incison was made from the anterior border of the sternocleidomastoid muscle to the pretragal region to expose the parotid gland. This skin incision, elevation of the parotid gland and division of the digastric muscle were useful for exposing the distal portion of the extracranial ICA. After trapping of the aneurysm, it was punctured and collapsed by aspiration and the dome was excised at its neck. The ICA was then reconstructed by suturing the cut neck of the aneurysm. Patency of the ICA was confirmed by postoperative angiography. The postoperative course was smooth except for hoarseness, which was caused by damage to a minor branch of the vagus nerve during exposure of the aneurysmal dome.