Abstract
We present a surgical case with a giant serpentine aneurysm of the left middle cerebral artery. A 56-year-old man was transferred to our hospital due to progressive motor paresis of the right side and difficulty speaking. Neuro-radiological examinations revealed a giant mass lesion in the left peri-sylvian region, which was 65mm in size and was diagnosed as a giant serpentine or thrombosed aneurysm. The aneurysm was incised through a left fronto-temporal craniotomy with the assistance of a preparative superficial temporal artery-middle cerebral artery (STA-MCA) bypass. While evacuating the thrombi, branches of the MCA had to be trapped due to premature bleeding from the aneurysm. After the trapping, motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs) became flat. The changes hastend us to a quick evacuation of the thrombi and a relocation of the temporary clips to restore MCA blood flow. The aneurysm, which was caused by diseased vasular wall, was finally trapped and excised. Postoperatively, the patient recovered from both the motor paresis and aphasia. Giant serpentine aneurysms are difficult to treat. However, aggressive treatment is often required because of the progressive deterioration of the patient's symptoms. Intraoperative monitoring of MEP and SEP may be helpful to prevent ischemic complications.
