Redesigning Intramedullary Nail to improve success rate October 14 2005 Tissue Engineering Design Team Team Members Erik Yusko Leader Tony Wampole BSAC Anna Moeller BSAC Jon Sass BWIG Danielle Ebben Communications Client Tass Dueland DVM Ray Vanderby Professor Advisor Professor William Murphy Problem Statement To improve the intramedullary nail in an effort to decrease misalignments that lead to the inability to secure the nail to the bone Background Intramedullary nails are used to repair long bone fractures Nails are inserted into the marrow of the bone and secured into place by screws on the proximal and distal parts of the fracture Most effective for clean fractures Background Extension piece attached to nail Nail inserted in bone Jig attached to extension piece Screws put in place by using jig guides Motivation Poor alignment of jig guide with nail screw holes results in complications with inserting screws Distal screws miss more often 4 of screws miss the target Need to strengthen extension piece nail interface Client Design Requirements Implement in current surgical procedure Maintain nail integrity Consist of only biocompatible materials Easily sterilized Reduce distal hole failure rate Design 1 Extra Bars Decrease the width of threaded screw Add 2 rods that go into the nail New rods perpendicular to screw holes Proximal Screw Holes Design 1 Pros and Cons Pros Moment arm perpendicular to jig reduced Doesn t allow rotation Still easy to use Cons Screw is smaller Likely allow more movement parallel to jig May effect integrity of rod Design 2 Conical Connection Force distribution increased Key prevent rotation around long axis Two areas were forces are now opposing motion Design 2 Pros and Cons Pros Easily implemented into surgical procedure Leaves most components unaltered Moments in all directions should be reduced Cons May be difficult to machine Design 3 Double Sided Screw Jig has conical hole Top extension screws into middle and also into nail Middle has hollow center to allow double sided screw through Nut attaches middle to nail H head and notch align holes Conce ptual not to scale Design 3 Pros and Cons Pros Cons Will reduce Increased difficulty movement around top joint Still align holes Stability of nail not reduced with more pieces Might not reduce movement in second joint Lengthens amount of nail left out of bone Design Matrix Design Extra Bars Simplicity Integration into process Cleaning Cost Potential Effectiveness TOTAL 1 5 1 10 1 5 1 5 1 10 5 35 4 9 5 3 7 28 Conical Connection 3 8 5 3 8 27 Doublesided Screw 4 7 5 2 7 25 Future Work Decide on Final Design Determine Design Parameters Build Test Prototype References Rassman W Bernstein R McClellan R Jones R Worton E Uyttendaele H 2002 Follicular Unit Extraction Minimally Invasive Surgery for Hair Transplantation Online http www newhair com resources p 2002 fue asp Willis B 2001 Hair Online http www wcsscience com hair page html Company Chemical Treatment Internal Document Rev B Mattmiller Brian 1998 April UW Biochemist solves riddle of collagen stability Retrieved October 4 2004 University of Wisconsin http www news wisc edu releases print php id 2995 Youngerman Cole Sydney Repair of the Vaginal wall Vaginal Vault Prolapse Online Retrieved October 7 2004 http my webmd com hw womens conditions tv1559 asp
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