title: Congenital Absence of Internal Carotid Artery with Rare Type of Intercavernous Anastamosis and Ruptured Cerebral Aneurysm.
abstract: Congenital absence of Internal Carotid Artery (ICA) is a rare anomaly seen in <0.01% of the population. Various collateral circulations develop in these cases to maintain adequate cerebral perfusion. High incidence of aneurysms is reported in these cases. Complete evaluation is required to detect other abnormalities usually seen in these patients. We report a case of congenital absence of right ICA in a 39-year-old female who presented with Subarachnoid Haemorrhage (SAH) and had a Middle Cerebral Artery Aneurysm (MCA). The right MCA got supply from the intercavernous communication from the left internal carotid artery. Skull base Computed Tomogram (CT) confirmed the congenital absence of right ICA. She underwent successful surgical clipping for the aneurysm. The high incidence of aneurysms, collateral circulations, embryological development and postulated mechanisms of this anomaly were discussed. The exact aetiology behind the absence of ICA remains unclear. It is important to differentiate this condition from acquired stenosis/occlusion due to atherosclerosis and carotid dissection. Recognising the anomaly is important and gains even more significance during surgical planning in cases of direct aneurysm clipping, carotid endarterectomy and transphenoidal surgeries.
authors.affiliation: Chief, Department of Neurointervention, King Edward Memorial Hospital , Pune, Maharashtra, India .
authors.forename: Anand
authors.initials: A
authors.lastname: Alurkar
authors.affiliation: Consultant, Department of of Neurointervention, King Edward Memorial Hospital , Pune, Maharashtra, India .
authors.forename: Lakshmi Sudha Prasanna
authors.initials: LS
authors.lastname: Karanam
authors.affiliation: Consultant, Department of of Neurointervention, King Edward Memorial Hospital , Pune, Maharashtra, India .
authors.forename: Sagar
authors.initials: S
authors.lastname: Oak
authors.affiliation: Consultant, Department of of Radiology, King Edward Memorial Hospital , Pune, Maharashtra, India .
authors.forename: Smita
authors.initials: S
authors.lastname: Kori
keywords: Carotid agenesis; Cerebral perfusion; Collaterals