Preclinical analysis of stents for microvascular anastomoses: A method to anlayse the tensile strength

In transplantation procedures vascular anastomoses are usually sutured. Although there are a lot of problems with suturing anastomoses no other technique, like gluing or lasering the anastomosis, could be establish in microvascular tissue transplantation. Therefore a method for anastomosing blood vessels with stents in clinical use of microvascular tissue transplantation has been developed. In this work we present a comparative method to determine the tensile strength of a stented microvascular anastomosis. It was also investigated, how length and dilatation of the developed stent influence tensile strength of the stented anastomosis. Overall 24 vessels of thiel-fixed human cadavers were investigated, divided into four groups (A: sutured anastomoses; B: 17 mm stent, dilation to Ø 2.5 mm; C: 23 mm stent, dilation to Ø 2.5 mm; D: 17 mm stent, dilation to Ø 4.0 mm). Prior to these analyses different gripping devices were additionally tested and validated. The results of our researches showed that sutured anastomoses got the best tensile strength of all tested anastomoses. Dilatated stented anastomoses (17 mm stents, Ø 4.0 mm expanded) reached half the tensile strength of the conventional sutured anastomoses. If the stent is less dilatated, only minor tensile strength of the anastomosis resulted. Stenting might become an alternative way to perform microvascular anastomoses to suturing and provide safety for the transplanted tissue especially in lack of surgical experience. Further studies to improve the implanting method and to enhance the grip between stent and vessel are necessary to develop a clinical useful stent for microvascular anastomosis.