CleanTools · Crevice-free, high reliability bi-metallic surgical instruments manufactured from shape memory alloys

Flexible medical instruments such as bone reamers are currently constructed from multiple parts in dissimilar materials, which have very different properties. The current method of linking these parts together is by mechanical coupling. Effective decontamination of such instruments is challenging but is critical to avoid cross infection between patients. The geometry of the instrument assembly (particularly bone reamers and similar tools used in joint implants) have crevices at the joints which are difficult and expensive to clean and fully sterilise. Welded instruments would eliminate this problem.Approximately 7000 cases of MRSA infections were reported in UK hospitals during 2007 and similar issues are prevalent across Europe. Such infections are of particular concern in post-surgery patients. The CleanTools project aims to develop technology which will reduce this issue by making surgical instruments easier to clean and disinfect. The crevice between stainless steel cutting heads and Shape Memory Alloy (SMA) flexible shafts currently makes decontamination challenging, time consuming and chemically intensive. Additionally there have been instances of cutting heads becoming detached from the flexible drive shaft during use, causing undue implications in theatre and potential long term impacts on patient quality of life.The desirable materials for these tools, such as SMAs and stainless steels, are challenging to weld and their properties are severely degraded when they are melted in conventional welding. CleanTools will provide a method for the manufacture of surgical instruments containing SMA materials though the use of rotary friction welding (RFW). RFW is a low heat input solid phase welding technology that will preserve the properties of the materials in question. CleanTools will improve the function of flexible surgical instruments, reduce the required cleaning and disinfection effort, improve reliability and reduce the cost of manufacture within Europe.