[Need for randomizing microvascular surgical experiments for testing new prosthesis material, with special reference to personal surgical errors from a morphological viewpoint].

In the examination of material involving two microvascular prostheses of different nature the need is discussed of randomising experimental series to achieve a self-critical control of operative dexterity in microsurgical techniques and to exclude eventual errors arising and influencing the results. A comparison was made of two polyurethane prostheses, one porous (n = 15), and the other covered internally with a smooth silicon layer (n = 15). They were implanted using microsurgical techniques into the infrarenal portion of the abdominal aorta in rats. The main criterion for successful implantation was a patency over a prolonged period of observation lasting a maximum of 407 days. The porous prosthesis showed the best results. Most frequent complications were early thrombosis and technical faults demonstrated by histology. Therefore, the distribution through prospective randomisation of good and bad results based on technical errors enhances the significance of material analysis.