Progress in diagnostic technology such as 3D-CTA and MRA has brought an increase in the surgical treatment of asymptomatic unruptured cerebral aneurysms (AUAn) and raised the importance of informed consent. We explain how we implement informed consent with patients with AUAn and report the results. This study covers 40 patients with 51 AUAns (16 males, 24 females, 63.8±9.1 years old) which were diagnosed between January 1996 and September 2001. Thirteen aneurysms were located at the internal carotid, 5 at the anterior cerebral, 25 at the middle cerebral, 8 at the vertebro-basilar artery. The decision to operate was based on the guideline of the Japanese Society for Detection of Asymptomatic Brain Diseases. Hemorrhage risk was explained to each patient with the use of a table that showed computed risk over a lifetime considering current age. Thirty patients with 35 aneurysms chose medical treatment. Thirty-four aneurysms (97.1%) were treated with clipping and 1 aneurysm (2.9%) with endovascular coil embolization. About 25 percent of patients selected for observation were selected for that group based on their own desire.
A table of computed hemorrhage risk over the course of a lifetime can show patients concrete numerical values. We believe it informed consent for patients with AUAn is effective.