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- Intramedullary Nail (1)
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A novel implant system for bone elongation will be presented. With this technique, the body's own bone material, so-called callus, can be formed by gradual distraction of the tubular bones, thus achieving an extension of femur and tibia bones. The driving principle of this fully implantable bone lengthening system is based on a shape memory element. During the surgical treatment, the intramedullary nail serves to stabilize the severed bone and enables the formation of new, endogenous bone material to lengthen the limbs or to bridge bone defects. The intramedullary nail is implanted into the medullary cavity and fixed at both ends with locking bolts. A receiver coil implanted under the skin receives the necessary energy twice a day through high-frequency energy transport to activate the thermal phase transformation of the shape memory element. This gradually increases the bone gap by 0.5 mm each time and stimulates callus formation. Consequently, osteoblasts or osteocytes are formed in the area of the desired bone extension and load-bearing bone material is formed. Three nail prototypes have already been tested for their functionality in a cadaver study in a German clinic. Currently a redesign of this intelligent implant system is underway, focusing on a novel coil geometry, a monitoring sensor system and control technology and a novel connection technology for the drive components. With this intelligent implant system, it will be possible for the first time to lengthen the bones in a patient-friendly manner and to continuously monitor, document and evaluate the entire lengthening process.
In the automotive industry a strong effort has been undertaken to reduce the weight of modern vehicles. In order to reduce the energy consumption and to improve the environmental sustainability, the importance of weight reduction activities is even growing faster. As lightweight designing is becoming more and more expensive and show less potential savings, new approaches are needed. One promising technology could be the use of shape memory elements. In the last years a lot of potential application possibilities were presented, demonstrating the benefit of these functional elements in automotive design solutions: they often reduce complexity, weight and design space of an actuation device and enable new functions. In addition they work silently and are therefore ideally suitable for comfort applications in the passenger cabin. Because of the current trend to electric vehicle the hitherto existing drawback of a high electrical energy consumption of shape memory actuators in some design proposals is not given any more.