1. Redesigning Intramedullary Nail : to improve success rate October 14, 2005

2. 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

3. 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.

4. 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

5. Background  Extension piece attached to nail  Nail inserted in bone  Jig attached to extension piece  Screws put in place by using jig guides

6. 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

7. Client/Design Requirements  Implement in current surgical procedure  Maintain nail integrity  Consist of only biocompatible materials  Easily sterilized  Reduce distal hole failure rate

8. 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

9. 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

10. Design 2: Conical Connection  Force distribution increased  Key prevent rotation around long axis  Two areas were forces are now opposing motion

11. 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

12. 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

13. Design 3: Pros and Cons  Pros:  Will reduce movement around top joint  Still align holes  Stability of nail not reduced  Cons:  Increased difficulty with more pieces  Might not reduce movement in second joint  Lengthens amount of nail left out of bone

14. Design Matrix DesignSimplicityIntegration into process CleaningCostPotential Effective- ness TOTAL (1-5)(1-10)(1-5) (1-10)(5-35) Extra Bars 4953728 Conical Connection 3853827 Double- sided Screw 4752725

15. Future Work  Decide on Final Design  Determine Design Parameters  Build & Test Prototype

16. 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. http://www.newhair.com/resources/p_2002_fue.asp  Willis, B. 2001 Hair! [Online] http://www.wcsscience.com/hair/page.html. 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 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