MATERIAL and METHODS: Experimental animals (rats) were assigned to one of four groups: Group 0 was the (normal) control group, Group 1 consisted of rats that had an operation using multiple incisions, Group 2 consisted of rats who received a midline incision and were raised for 3 months, and Group 3 consisted of rats who also received a midline incision, but had been raised for 6 months. Rat blood pressure was measured by tail cuff method. The surgical characteristics and outcomes of the rats in Groups 1 and 2 were compared. Aneurysmal lesions of both branching and non-branching sites were compared amongst the 4 groups by observation of the cerebral vascular corrosion casts through a scanning electron microscope. Histological analyses of the induced aneurysms were performed.

RESULTS: The simplified incision technique significantly reduced the length of surgery and need for anesthesia redose during the operation. No aneurysms formed in the normal control rats. The incidence of saccular aneurysm formation significantly increased in Group 3. Histological analyses confirmed the aneurysms induced in the rats shared the same characteristics as human aneurysms.

CONCLUSION: Our modified surgical method reduced the surgical stress in rats. It also successfully induced both saccular and fusiform cerebral aneurysms. While longer incubation duration for aneurysm formation could be applied in future researches. Keywords : Cerebral aneurysm, Animal model, Oophorectomy, Etiology, Rats