METHODOLOGY FOR RESEARCH AND DEVELOPMENT OF NOVEL MEDICAL DEVICES FOR MINIMALLY INVASIVE INTERVENTIONS

The design of innovative medical device requires extensive and hard efforts to reach good results in terms of safety, efficacy and cost effectiveness. First of all the idea has to be set and a wide search of state of the art, both technological and academic, has to be developed. Then the materials, manufacturing processes and design constraints have to be understood. In this work three examples of innovative surgical devices for minimally invasive surgery and assistance have been presented. The Muneretto Beam catheter is a new device for atrial defibrillation. Starting from a catheter produced by Estech company for the treatment of atrial fibrillation by ablating cardiac tissue during surgery, a system for the magnetic guidance of the same has been implemented. Thanks to finite element analysis of various configurations of magnets and to several in vitro tests, a final configuration which allows a good balance between the sliding of the catheter on the tissues and the magnetic interaction and adhesion to tissues has been found. Further attention has been taken to the development of the cover and the right configuration and method of use of the device. The VideoDrain system is a new catheter for the monitoring of post-operative wound. After critical surgical procedures it is necessary to monitor the status of the surgical wound for avoiding second look surgical interventions. Therefore a new balloon catheter for allowing the vision of the abdominal cavity has been produced. Several in vitro and in vivo trials have been conducted and the device is at the pre-industrial stage. The FloSeal GI cath. is a new device for the gastrointestinal release of an haemostatic substance of the Baxter company: the Floseal thrombin matrix. It consists in a balloon catheter suited for the use in the lower and upper gastrointestinal tract in the occurrence of bleedings during endoscopic procedures. This device has been CE labelled and is now on the market. All the devices described in this work come from ideas of surgeons leader in innovation in the field of minimally invasive interventions. Their collaboration has been fundamental for the several phases of design and tests of the devices. This Ph.D. thesis is divided into five chapters. In the Introduction chapter the process of research and development of innovative MDs for minimally invasive surgery has been illustrated. The second chapter shows the efforts done to find a working configuration for the Muneretto Beam catheter and the subsequent first prototypes developed. The progress in the design of VideoDrain has been explained in the third chapter; the whole process goes from the idea to the animal test on prototypes and a preliminary risk analysis. The development of the Floseal GI Catheter is depicted in the fourth chapter; all the details of the materials used and tests done to ensure a CE mark have been reported. Finally, in the Conclusion chapter I have reported some lessons learned from the work in the field of MDs, as a student, researcher and engineer at close contact with the world of surgery and minimally invasive technologies. Some papers about a preliminary research activity in the field of minimally invasive surgery and robotic interventions have been also enclosed. These works have been very useful to start the understanding of the complex and amazing world of MIS.