Experimental microaneurysms in rats: II. Comparison between cotton wrapping and microbipolar coagulation

Abstract Background Microsurgical aneurysm clipping is considered the best treatment for intracranial aneurysms, but often it cannot be used for microaneurysms. These aneurysms may require different type of treatment like bipolar coagulation or wrapping to reinforce the aneurysm wall, but these treatments have no experimentally proven efficacy. In this study the authors analyze the efficacy of 2 methods of treatment to prevent rupture of experimentally induced microaneurysms. Methods Microaneurysms were induced using mechanical compression of the wall of the aortic bifurcation in 60 rats. The animals were divided in three groups according to aneurysm treatment: Group 1—aneurysms treated using microbipolar coagulation; Group 2—aneurysms wrapped with cotton, and Group 3—no treatment. Four weeks after the treatment, the resistance of the microaneurysm was tested applying intraluminal hyperpressure (up to 2,427 mm Hg). After that, the vessels were microscopically analyzed. Results No rupture of the aneurysms was observed in Group 2 and all aneurysms ruptured in Groups 1 and 3 during the resistance test. Comparison between the mean bursting pressure of Groups 1 and 3 showed no significant difference (Student's t test, p > 0.05). The probability of rupture of the microaneurysms was significantly different between Groups 1 and 2, favoring Group 2 (Fisher exact test, p Conclusions Wrapping of experimental microaneurysms with cotton was effective to protect aneurysm rupture under hyperpressure; and there was no protection using microbipolar coagulation.