Proceedings of ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis ESDA2010 July 12-14, 2010, Istanbul, Turkey ESDA2010-24286 MECHANICAL DESIGN AND PROTOTYPING CONSIDERATIONS FOR AN INTRAMEDULLARY NAIL FOR EXTENDING BONE SECTIONS A. Fethi Okyar * , Koray K. Safak and Nilufer Egrican Department of Mechanical Engineering Yeditepe University Atasehir, Istanbul 34755 Turkey ABSTRACT An orthopedic distractor device is currently being developed for extending bones or bridging a gap in a bone. The device is de- signed to fit into the medullary canal of a human femur or tibia. By virtue of telescopic motion between two mating parts, the de- vice can extend axially inside a dissected bone, elongate it to desired length. The distractor is actuated by means of a minia- ture electrical drive system, which is energized and controlled from outside of the body without any direct physical connection or cabling. In this study mechanical design and prototype manufactur- ing considerations of the intramedullary distractor device are discussed. An important limitation in design of this device is the availability of a suitable drive system that will fit into the intramedullary space of the bone, which has a diameter of less then 12 mm. The nail must withstand axial forces with a magni- tude of 2000 N, which is exerted by extending the muscles, espe- cially during the late stages of the distraction operation. Since the designed device is intended to be used inside the human body, proper insulation from the surrounding body fluids must be pro- vided, thus sealing is also an important design consideration. A preliminary design is presented that will achieve the desired re- quirements. Keywords: limb extension, telescopic devices, bone dissec- tion, orthopaedic treatment, biomedical devices, product devel- opment * Address all correspondence to okyar@yeditepe.edu.tr INTRODUCTION Development of hi-tech limb-extension devices has become a source of attention for mechanical engineers during the last couple of decades. Traditional methods such as Ilizarov’s are still popular due to their low cost, however at the higher end, new de- vices are promising patients a shorter recovery period. The cost associated with these operations prevent them from becoming widespread. The feasibility of developing such biomedical de- vices, especially those aiming the local markets, is heavily scruti- nized. Nonetheless, in this study the subject matter is undertaken at least from a research and development framework. Here we present a straightforward bold approach towards the development of an intramedullary skeletal distractor (ISD) device. An interdisciplinary team consisting of mechanical and electronics engineers, and orthopedicians from the medicine fac- ulty was formed in 2003 at the Yeditepe University. The team had several obejectives at the start of the project. ◽ To determine the performance criteria of ISDs ◽ To determine the testing conditions of ISDs ◽ To undertake mechanical design of a prototype device ◽ To undertake electrical design of a prototype device ◽ To obtain life estimates of ISDs ◽ To integrate and test the system as a whole An increasing number of authors have focused on the clini- cal test results related with intramedullary nail systems. Here we look at two such studies, one of which present the operational characteristics of a brand nail and the other primarily focuses on 1 Copyright © 2010 by ASME Proceedings of the ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis ESDA2010 July 12-14, 2010, Istanbul, Turkey ESDA2010-