Subcallosal and Heubner artery infarcts following surgical repair of an anterior communicating artery aneurysm: a causal relationship with postoperative amnesia and long-term outcome.

Since the 1950s, amnesia or memory impairment has been repeatedly reported in patients following surgical repair of anterior communicating artery (ACoA) aneurysms. Postoperative infarctions following surgical repair of ACoA aneurysms are classified as involvement of the subcallosal artery (the largest unpaired perforator of the ACoA), the recurrent artery of Heubner (RAH), or a combination of both. Postoperative amnesia can seriously affect the patient's quality of life, thus prompting physicians to discuss the symptomatology of the three infarction patterns. We made the following speculations regarding the causal relationship between the infarction pattern and postoperative amnesia. First, postoperative amnesia is most likely caused by an infarction in the territory of the subcallosal artery, particularly in the column of the fornix, a constituent of the Papez neuronal circuit. Second, infarction in the RAH territory alone is unlikely to cause significant amnesia. Third, infarcted foci in the RAH territory, when associated with a subcallosal artery infarction, can cause considerable frontal dysfunction due to impaired frontostriatal circuits in patients with postoperative amnesia, with resultant worsening of the long-term outcome or quality of life.