[Experiments on new synthetic and non-absorbable surgical threads]

The aim of this work was a complex evaluation of synthetic non-absorbable surgical threads of the latest, so called 3rd generation: Novafil, Monolene and Fore-Tex. Biological tests in vivo were carried on 90 white rats of the Wistar tribe. The animals were divided into three experimental groups depending on the kind of the implanted surgical thread. Moreover, taking into account the place of implantation of the tested threads, each group was divided into two sub-groups containing 15 rats each. Operations were carried on in the conditions of surgical aseptics implanting the tested threads into the striated muscles of the back and into the liver in order to make macroscopic and microscopic tests of tissue reaction and also into the peritoneal cavity in order to carry out resistance tests after a different time of the threads stay in the tissues. The animals' sections were carried out 7, 14, 21, 90 and 180 days after the implantation of the above mentioned threads. On the basis of many year's experience of The Institute of Experimental Surgery and Biomaterial Research and review of 52 works of specialistic literature I have chosen the following additional criteria of evaluation: tests of stability of surgical knot, tests of resistance in the knot to break, tests of surgical convenience including easiness of carriage of the tested threads through the tissues, flexibility, absorbability, possibility of coiling of a loose segment of threads, electrifying and the security of the knot. Tissue reaction was based on macroscopic and microscopic tests. In macroscopic tests we paid attention to the course of healing of the threads in transversostrated muscles and in liver tissue paying attention to the behaviour of the organs of o the abdominal cavity during the section. Characteristic pictures are documented by photographs. Microscopic tests consisted on making histological samples of the threads together with the surrounding tissues. Microscopic evaluation was carried on 1080 samples using punctual of tissue reaction. The used punctual system for describing tissue reaction after implantation of non-absorbable surgical threads includes the number and degree of condensation of cells in the vicinity of the implanted thread, the width of the sphere of the inflammatory reaction and the histological analysis of the cells type. The used punctual evaluation enables objective evaluation of the tested histological samples. Variously evaluated threads Novafil, Monolene and Gore-Tex are characterised by large resistance, very good surgical convenience and minimal tissue reaction. On the basis on the carried out laboratory tests and tests on animals the following conclusions were made: 1. Non-absorbable surgical threads Novafil, Monolene, Gore-Tex do not make organism changes and heal with minimal tissue reaction what proves their high biocompatibility. 2. The used punctual evaluation of the tissues reaction after implantation of non-absorbable surgical threads allows complex and objective classification of the degree of tissues reaction. 3. Monofibrous surgical threads Novafil and Monolene do not lose resistance to break in the knot. 4. Surgical threads Novafil and Monolene are characterized by very good security of the knot while threads Gore-Tex have large flexibility and small coefficient of friction, which is the cause of weak security of the knot in case of fastening under tension. 5. Tissues reaction after implantation of synthetic non-absorbable surgical threads Novafil, Monolene and Gore-Tex is smaller in comparison with the tissues reaction which were caused by non-absorbable surgical threads tested in the former years. 6. In comparison with the non-absorbable surgical threads tested in the former years, very good surgical convenience, lack of loss of resistance to break in the knot and minimal tissues reaction give the basis to classify threads Novafil, Monolene and Gore-Tex to improved non-absorbable surgical threads of the new generation