Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis. Pathological study of two cases.

Superficial temporal artery to middle cerebral artery (STA-MCA) anastomoses were examined at autopsy in two patients who survived 2 years and 5 1/2 years, respectively, after the cerebral revascularization procedure. Identification of the actual anastomotic sites at autopsy was rendered impossible because of marked fibrosis in the region of the surgery. However, in both patients intimal fibrosis and medial damage were noted in the STA immediately adjacent to the anastomosis. In the patient who survived 2 years, the lumen of the STA was only slightly compromised by these changes, but in the patient who survived 5 1/2 years, the artery was almost totally occluded. The MCA's adjacent to the anastomosis were widely patent and showed focal areas of intimal hyperplasia with no abnormalities of the media.