2004 Volume 32 Issue 3 Pages 179-182
The optimal strategy for treatment of unruptured aneurysms remains controversial because of their natural history. Especially the nature of the aneurysmal wall remains uncertain.
To elucidate them, we retrospectively analyzed intraoperative findings of unruptured aneurysms. Fifty-six patients with 70 asymptomatic unruptured aneurysms were microsurgically treated during January 1999-March 2002. The location, size, and the irregularity and thickness of domes were examined retrospectively with the operation video and records.
The patient population comprised 23 male and 33 female patients aged 38 to 78 years (mean age 61.7 years). Twenty aneurysms were located in the internal cerebral artery, 35 in the middle cerebral artery, and 15 in the anterior cerebral artery. Thirty-one aneurysms had irregular-shaped walls, and 39 aneurysms were smooth-walled. Thinning of dome was observed in 61 aneurysms, and among them 30 aneurysms had thin, transparent walls. The incidence of irregular-shaped aneurysms in medium-sized (5-9 mm) and large-sized aneurysms (10-25 mm) was significantly higher (p=0.020 and p=0.020) than that of small-sized aneurysms. Even in small aneurysms (3-4 mm) 15 aneurysms had thin walls, and transparency was recognized in 8 aneurysms. Twenty-four of 34 irregular-shaped aneurysms had thin, transparent walls and only 6 of 36 smooth-walled aneurysms showed transparency. There was a strong correlation between the irregularity and thickness of domes (p<0.001). With growth of aneurysms, thickening and thinning of the dome were intermingled and thin blebs were frequently recognized. These findings indicate that most irregular-shaped aneurysms have thin walls and deserve to be surgically treated regardless of size.
