Features of the integration of two-layer metal knitwear made of titanium nickelide during the replacement of a thoracoabdominal defect in the experiment

The aim of investigation was to study experimentally the morphological features of tissue integration of two-layer titanium nickelide (TiNi) knitwear when replacing thoracoabdominal defects.Materials and methods. The experiments were carried out on 40 Wistar rats. The experimental animals were divided into two comparison groups: in Group A (n = 20) the defect was replaced using a two-layer knitted tape made of TiNi, in Group B (n = 20) a polypropylene mesh implant was used. The technique of the operation and the peculiarities of keeping the animals did not differ. Animals were taken out after 14, 30, 60 and 90 days of experiment. The macroscopic structural features at the site of implant fixation to tissues and at the sites of contact with underlying organs were studied, and the inflammatory process was assessed. The histological and electron microscopic study was carried out with an assessment of the features of tissue integration through the mesh structure of knitwear.Results. Thirty days after the surgery in four cases of Group B the appearance of the chest wall deformation at the site of implant fixation was noted, in one case the deformation site was located along the lateral edge of the abdominal wall. Among the animals of Group A no such changes were recorded. The histological and electron microscopy examination revealed that the porous structure of the TiNi wire, as well as the biomechanical and biochemical properties of the two-layer metal knitwear, ensure optimal integration of the endoprosthesis in the body tissues, forming an elastic frame close to natural. In Group B, on the contrary, the reaction of the body caused by the implanted polypropylene prosthesis was characterized by more pronounced fibrosis, and tissue integration through the mesh structure of the implant was not observed.Conclusion. Two-layer TiNi knitwear in the replacement of complex structures of the thoracoabdominal zone showed promising results, which opens up prospects for further clinical research.