The Effect of Radiation on the Patency of End-to-side Microvascular Anastomosis

Nowadays, more aggressive local control of primary cancer site is believed to be the most effective among the oncologists. However, this aggressive local control of cancer leaves a large defect of tissue which needs the reconstruction by a plastic surgeon.Post-oncologic reconstruction usually needs to use free flap coverage rather than local flap because of extensive tissue defect and post-radiation fibrosis. End-to-side microvascular anastomosis rather than end-to-end microvascular anastomosis is necessary especially for limb salvage in case of malignant cancer of the limb or for saving the important recipient vessel. The effect of radiation of end-to-end microvascular anastomosis was revealed to be minimal in the previous studies, but the effect of radiation on end-to-side microvascular anastomosis has not been researched up to present. The authors designed this experimental study model to clarify the effect of radiation on the patency of end-to-side microvascular anastomosis. For control group, total 20 rats were used. In one control group which consists of 10 rats, end-to-side microvascular anastomoses were carried out on their carotid arteries. In the other control group of 10 rats, end-to-end microvascular anastomoses were done. In radiation groups, 2000 rad X-radiation(peak 250 kV, 30 mA) was given on the neck areas of 40 rats. In two radiation groups, each of which consists of 10 rats, end-to-end and end-to-side microvascular anastomoses were carried out respectively on their carotid arteries 3 weeks after radiation. In another two radiation groups, each of 10 rats, the same procedures were done respectively 6 weeks after radiation. On the fourth week after anastomsis, the vascular patency and histological examinations were done. This study revealed that no effect of radiation on the vascular patency was found depending on both types of microanastomoses although some histologic changes were evident.

The Effects of Elliptical Versus Slit Arteriotomy on Patency in End-to-Side Microvascular Anastomosis

The fashion of vascular anastomosis, end-to-end or end-to-side (E-to-S), are depended upon surgeon's preference or surgical situations. In E-to-S anastomosis two different methods of arteriotomy are applicable but it has been suggested the type, either elliptical or slit arteriotomy, play a different role in the flow hemodynamics. We thought that the difference is more considerable in microvascular surgery. This study examines the effects of elliptical versus slit arteriotomy on morphologic vessel patency. Twenty male Sprague-Dawley rats were divided into two groups of ten rats each. Both carotid arteries were selected as a experimental model. During the procedures the rat brain was tolerable to ischemia and all animals were survived after operations. The morphologic analysis of anastomosis site was through resin-casting method with scanning electromicroscopic examination. The results showed notable difference between two groups in three-dimensional morphology at two-month of operation. This difference may affect the flow hemodynamics and long-term vessel patency. In microvascular anastomosis, the mortpologic difference of the elliptical arteriotomy is worse than slit arteriotomy which compromises the vessel circumference.