Treatment of asymptomatic unruptured intracranial aneurysms. A clinical decision analysis

The indication of preventive surgery for patients who harbor asymptomatic un ruptured intracranial aneurysms remains controversial. To evaluate the benefit of this treatment, we investigated the management outcome in 128 patients with 157 unruptured aneurysms. Surgery was planned in patients 70 years old or younger without serious systemic complications. A total of 77 patients underwent surgery including four endovascular interventions, and conservative management was chosen in 51 patients. There was no mortality and 6.5% morbidity as postoperative results, and no complication was found after endovascular treatment. Among the patients in conservative management, four patients suffered from subsequent rupture during the total follow-up period of 148 person-years. The annual rupture rate was estimated at 2.7%. According to the clinical decision analysis based on our data, preventive surgery is beneficial for a Japanese 70 years old or younger. However, the expected utility decreases if the rupture rate is set at 0.5% or 0.05%, posing a doubt about the benefit of the surgery. Decision analysis provides an aid for logical and objective choice in the management of unruptured aneurysms. The actual risk of rupture has a major impact on decision making in therapeutic strategy.