Abstract
A follow-up study of 265 patients treated by microsurgical techniques for ruptured intracranial aneurysms at the Department of Neurological Surgery of the Radcliffe Infirmary, Oxford from 1972 to 1977 showed that prediction of results in terms of mortality, and various measures of morbidity could be achieved by considering before operation several variables in combination. Age, systemic blood pressure on admission and before operation were the most important factors in determining outcome. Inclusion of a variable following operation-arterial spasm-was found to improve prediction somewhat. In addition, spasm was found to be the single most important factor in predicting both mortality and morbidity.