Comment on the Article “Unruptured Intracranial Aneurysms — Risk of Rupture and Risks of Surgical Intervention”

Abstract

The importance of this study needs to be stressed, because it questions two well-established ideas on unruptured aneurysms. The restrospective part of the study shows that the actuarial risk of bleeding of an incidental aneurysm is far lower than is currently believed 1. The prospective part shows that the surgical risk of unruptured aneurysm is much higher than the surgical series published so far lead us to think2. To note: 1) the patients included in the prospective study were enrolled between 1991 and 1995, i.e., during a period where the most up-to-date surgical tools and neuro-anesthetic techniques were available; 2) the patients were freely selected by the operators; 3) the study operators were known nationally or internationally for their expertise in aneurysm surgery. These results therefore reflect the surgical reality of unruptured aneurysms. The discrepancy with previously published retrospective series can be explained only by the presence of an independent clinical evaluator in the prospective study. Analysis of the surgical risk factors finds a relation only with the patient's age. This contradicts most surgical studies, particularly that from the Henry Ford Hospital3, where three main risk factors were identified. These were the patient's age, the sac size, and its location. One can assume that the giant aneurysms or those of the posterior circulation were among the 15% of patients treated by an endovascular approach, but the study does not address this. Thus, this series does not allow evaluation of the endovascular treatment risk, which should also be assessed prospectively.