Scanning electron microscopic evaluation of nonocclusive excimer laser-assisted anastomosis in rabbits

The nonocclusive Excimer laser-assisted bypass technique has been described in previous studies and proved to be a promising bypass operation in vascular brain surgery. Little is known about the morphological regeneration process of the laser-assisted anastomosis in time. By way of a scanning electron microscopic study we examined the way in which the anastomosis site created by the nonocclusive Excimer laser-assisted anastomosis technique becomes endothelialized.

In 14 rabbits the internal jugular vein was placed in a loop on the abdominal aorta. The distal anastomosis was made using the nonocclusive Excimer laser-assisted technique. The proximal anastomosis was made either laser-assisted or conventional end-to-side. After clipping of the aorta between the two anastomoses sites the vein served as a bypass. To evaluate the endothelialization at the laser-assisted anastomosis site in time, a scanning electron microscopic study was performed.

In the first hours after the bypass operation a new intimal surface is formed by fibrin and activated platelets. Some leukocytes are seen during the first days. The endothelialization process of the laser-assisted anastomosis site begins one day after the operation. The gradual endothelialization process evolved along two lines. First, endothelial cells grow from the side of the aorta to the bypass. Second, after one day solitary (blood-borne) endothelial cells deposit on the laser edge and the sutures, covering the platelet aggregates.

The endothelialization of the Excimer laser-assisted anastomosis is more or less completed 9 days after the operation. The edge created by the laser becomes smoother after a few days and is gone for the most part after 9 days.