Saccular Aneurysm at the Anterior Communicating Artery Complex Associated with an Accessory Middle Cerebral Artery : Report of Two Cases and Review of the Literature

Abstract

J Korean Neurosurg Soc 46 : [568][569][570][571] 2009 Accessory middle cerebral artery (MCA) is an infrequent vascular anomaly of the brain. Cerebral aneurysms associated with this anomalous artery are also very rare. To our knowledge, there have only been ten previous reports of an aneurysm associated with accessory MCA. The authors present two patients with accessory MCA-related aneurysms. A 38-year-old male and a 59-year-old female both presented with suddenonset severe headache. In both patients, computed tomography (CT) scan revealed subarachnoid hemorrhage. A subsequent angiogram demonstrated an accessory MCA arising from the anterior cerebral artery (ACA) and a saccular aneurysm at the anterior communicating artery (ACoA) complex associated with an accessory MCA. Surgical clipping allowed for complete exclusion of the aneurysm from the arterial circulation. Based on our review of the ten cases of aneurysms associated with accessory MCA documented in the literature, we suggest that accessory MCA-related aneurysms can be classified according to whether the accessory MCA originates from the proximal A1 segment or from the ACoA complex. We also emphasize the importance of precise interpretation of preoperative angiograms and intraoperative precaution in determining the presence of this anomalous artery prior to temporary clip placement.

Acute Cerebral Infarction Related to Stenosis of Accessory Middle Cerebral Artery

“…With respect to the clinical signifi cance of the accessory MCA, it has been outlined in several case reports and has been found to be associated with intracranial aneurysms, [4][5][6][7] concomitant Moyamoya disease, 8 occlusion of the MCA or internal carotid artery (ICA), 9,10 and ischemic stroke. 11,12 The association of the accessory MCA and cerebral aneurysms has been well documented.…”

“…It has been suggested that hemodynamic stress is an important causative factor in the development of an aneurysm at the junction of an accessory MCA and the ACA, where the blood fl ow in the accessory MCA is recurrent to that in the parent vessel. 6 In patients with Moyamoya disease, the accessory MCA has been highlighted as a collateral blood supply in the MCA territory. 8,10,11 But there have been few reports about the ischemic stroke associated with stenosis of the acces-…”

Review on the anatomy of the middle cerebral artery; cortical branches, branching pattern and anomalies

“…(5,17,37,39,73). The duplicated MCA usually supplies the temporal lobe and the accessory MCA typically supplies the frontal lobe (25,30,57,60,77,80).…”

Relationship between the morphology of A-1 segment of anterior cerebral artery and anterior communicating artery aneurysms

“…The A-1 segment appeared from exterior-superior to interior-inferior in convex, inverse lateral "S" or approximate linear shape caused decrease of vertical distance between ACA Complex and anterior skull base 14 . The aneurysm adhered tightly to skull base, optic chiasma and nerves, which would easily cause abnormal bleeding with excessive dragging during operation.…”