There are many studies about asymptomatic unruptured cerebral aneurysms (AUAn), but we still have no evidence for those treatments. We report the management and treatment results for patients with AUAn in our department.
In principle, the decision to operate for AUAn was based on the guideline of the Japanese Society for Detection of Asymptomatic Brain Diseases. As regards informed consent, hemorrhage risk of AUAn was explained with the use of a table showing lifetime risk for patients with AUAn. Intraoperative digital subtraction angiography (DSA) and microvascular Doppler sonography had been routinely utilized since May 1997 in surgical clipping. A portable DSA unit (Siremobil 2000, SIEMENS) was used for intraoperative DSA.
We reviewed clinical features of 88 cases with 111 AUAns (30 males, 58 females, 63 years old±11 years) that were diagnosed and underwent angiography between January 1992 and July 2003. Fifty-one cases (58%) were treated, and 37 cases (42%) were untreated. Fifty-five aneurysms were treated with clipping and 1 aneurysm was treated with endovascular coil embolization.
By introduction of informed consent with the guideline and lifetime risk for AUAn, the patients who did not choose an operation had increased. Moreover, the patients aneurysmal size under 4mm in diameter and the patients aged over 70 years had tended to follow up without surgery. Of the 28 aneurysms evaluated by intraoperative DSA, there was no complication with the technique of angiography. After introduction of intraoperative DSA and microvascular Doppler sonography, the morbidity had decreased from 15.4% to 7.1%.
Informed consent with the guideline and lifetime risk for AUAn is useful whether patients choose an operation or not. We believe the use of intraoperative DSA and microvascular Doppler sonography is effective because it improves the result of clipping.