Fiber-reinforced plastics enable new prospects for minimal invasive devices and interventions

Since 20years, minimal invasive interventions help to realize successful treatments with minimal trauma for the patients. The medical devices that are used for minimal invasive interventions need to have several outstanding properties to realize all their functions in combination with the required small dimensions. Therefore, a high specific mechanical stiffness and strength, defined chemical, electrical and magnetic properties, as well as biocompatibility and visibility for different imaging methods have to be realized by the used materials. The Gold Standard materials for such minimal invasive devices are metals and special alloys as well as biocompatible plastics. These isotropic materials are limited in the performance of the listed requirements. Fiber-reinforced plastics (FRP) offer the possibility to face these requirements by the combination of different fiber and matrix systems in combination with special additives, so customized anisotropic materials can be designed directly for the intended usage. Especially for patient-friendly interventions under MRI control fiber-reinforced plastics are unrivaled to other materials. For the manufacturing of such miniaturized medical devices made of FRP, the Fraunhofer IPT develops production processes like a continuous and automated micro-pultrusion and micro-pullwinding process to ensure reproducible and high quality products with customized properties. This paper shows the successful development, the production processes and the material properties of fiber-reinforced guidewires, needles and catheters. These devices have outstanding mechanical properties and allow safe interventions in MRI for the first time. Caused by the continuous production process, the length of the devices can be freely defined with diameters of under 500m at the same time. Furthermore, these miniaturized profiles can be manufactured with more than one lumen for the integration of additional functionality. Also the contrast for visibility in X-ray and MRI can be exactly adjusted by additives as the material itself causes no annoying artifact