Arterial aneurysm model using laser energy.

Continuous wavelength laser energy can be used to perform arterial anastomoses, but all experimental series report an incidence of anastomotic aneurysm formation. To elucidate the mechanism of aneurysm production, controlled injuries of the arterial wall were created with a pulsed CO2 laser beam (40-50 mW). One carotid and one femoral artery of 10 New Zealand rabbits were injured with laser and the contralateral vessel was exposed surgically as a sham operation. At reoperation 8 to 11 weeks later, all 40 arteries were patent. None of the carotid shams, one carotid laser, two femoral shams, and eight femoral laser vessels (80%) were aneurysmal. Histologic examination revealed extensive medial necrosis with fragmentation of the internal elastic lamina in the area of these aneurysms. Femoral vessels were significantly smaller than carotids (P less than 0.001) and the high incidence of aneurysm formation in the former may be due to the relatively greater area of injury. This new model of aneurysm formation after laser injury suggests a need for further study prior to clinical application of this technology, especially in vessels smaller than 2 mm in diameter.