The Prediction of Morbidity and Mortality in Anterior Communicating Aneurysms Treated by Proximal Anterior Cerebral Ligation

Abstract

Y a t tempt to solve the problem of proper t rea tment for intracranial aneurysms must commence with delineation of the factors determining prognosis. Once these factors are known, they m ay be combined into a single expression of prognosis which has been called a discriminative function or equation. 1-3,s We have already described a discriminative function for the prediction of the natural course of aneurysms of the anterior 12 and posterior 13 communicat ing arteries. I n anterior communicat ing aneurysms, the age, blood pressure, level of consciousness, direction in which the aneurysm points, shape of the aneurysm and time elapsed since the original bleeding episode were all found to be closely correlated with the incidence of rebleeding. We derived a formula which weighted each factor and combined them all into a single equation. By means of this equation a score was obtained that could be compared with the expected mortali ty rate if the patient was simply treated with 6 weeks of bed rest. Thus it was possible to determine for each individual with this type of aneurysm, the statistical probability of rebleeding if only conservative therapy was undertaken. This paper presents a discriminative function by which morta l i ty can be predicted in one type of operative approach to anterior communicat ing aneurysms, namely the procedure described by Logue2 This consists of occlusion of the proximal anterior cerebral ar tery on the side from which the aneurysm fills best.