72 pt1 in 25.4 mm 54 pt 0.75 in 19.1 mm 54 pt 0.75 in 19.1 mm 54 pt 0.75 in 19.1 mm Margin requirements for first page Paper size this page US Letter Abstract—One of the most challenging parts of intramedullary nailing is finding the location of the distal holes of the intramedullary nail following its insertion along the medullary canal. The preferred method for locating the distal holes involves the use of x-ray imaging. In order to reduce the exposure of the medical personnel and patient to ionizing radiation several alternative methods are being investigated and their feasibility and accuracy are being assessed by performing surgery on cadavers. Due to several issues associated with cadavers, this paper introduces a phantom as an alternative tool for the evaluation of such techniques. The features associated with this phantom should allow researchers to assess the performance of their distal locking systems at a reduced cost and without the need for surgical skills. Key words – Intramedullary nailing, distal hole targeting system, cadaver, phantom, ionizing radiation. I. INTRODUCTION Intramedullary nailing (IMN) is the preferred method of choice for the treatment of fractures of the femoral shaft as it is associated with very good stability, less soft tissue injury and blood loss, less incidents of nonunion, delayed union, and malunion, shorter hospitalization time, and earlier mobilization of the patient compared to other methods [1]. According to orthopedic surgeon reports, the most challenging part of IMN is locating and drilling the interlocking screw holes [2]. IMN interlocking requires the surgeon to locate the holes in the nail, center the drill, and advance the bit through the bone to meet them. Interlocking screws are then inserted. Proximal locking is achieved using a mechanical guide, which is fixed to the proximal portion of the nail. Usually, the surgeon does not encounter any difficulties in inserting the proximal screws. On the other hand, the mechanical guide does not work well for the distal hole locking task. The reason is that as the nail traverses along the medullary canal it becomes deformed [3] due to the non-linearity in the shape of the canal and adapts to the shape of the bone. This deformation at the level of the distal holes may reach several millimeters [2]-[4]. Failure to properly lock the distal holes may lead to other complications such as poor stabilization, * This paper was made possible by a UREP award [UREP12015-2-004] from the Qatar National Research Fund (a member of The Qatar Foundation). The statements made herein are solely the responsibility of the authors. Fadi T. Jaber is with the Department Of Electrical Engineering, Qatar University, Doha, P.O. Box 2713, Qatar (phone: 00974-4403-4227; fax: 00974-4403-4201; e-mail:
[email protected]). Awni B. Al-Jayyousi, is with Amber House, Khalda, Amman, Jordan (e- mail:
[email protected]). distal fracture fragment rotation and bone weakening due to large or multiple screw holes that the surgeon drills. The challenge of distal hole locking is usually solved by taking several x-ray images in order to locate the exact position of distal holes [5], [6]. Nevertheless, the surgeon’s direct radiation exposure varies from 3.1 min to 31.4 min per operation, depending on his experience and skills, with 31%–51% of the total exposure being from distal hole locking only [7]-[10]. To minimize the requirement for x-ray images and reduce the amount of ionizing irradiation for the patient and medical staff, several alternative techniques have been reported in the literature. These include improved mechanical guides for distal hole locking [11], [12], self-locking nails [13], reference metallic grids [14], computer-based navigation systems [15], [16], laser guidance systems [17], robot- assisted guides [18], optical targeting systems [19], [20], and magnetic targeting systems [21], [22]. To evaluate the success of these distal targeting techniques, researchers usually go through the process of testing their systems in vitro where the nail is inserted into a plastic femoral model in order to measure the accuracy of the method [23]. Nevertheless, the use of plastic bone models alone is not sufficient since it does not mimic the actual IMN surgery. To overcome this problem in vitro experiments are often performed on cadavers or cadaveric parts before researchers can proceed with clinical trials [24], [25]. The use of cadavers provides a fair representation of an IMN surgery scenario and helps investigators to adjust their system for clinical use. In addition, the use of cadavers for in vitro experiments provides researchers with a three-dimensional view of the required anatomy [26], nonetheless, it does not always deliver an accurate impression of the living body [27]. Furthermore, cadavers are expensive, in short supply, their dissection is time-consuming and requires the presence of a skillful surgeon. Furthermore, their use is associated with several moral and ethical issues. Considering the aforementioned, the work described here introduces a phantom comprising leg tissue, a femur bone and an IM nail that can be used for evaluating the accuracy of distal hole targeting systems and that may overcome several issues related to cadavers and cadaveric parts. In the remainder of this paper section II describes the different parts that constitute the proposed phantom and section III discusses the potential advantages and limitations of such a model. Finally, section IV concludes the work and reveals future plans. A Phantom for Cadaverless Evaluation of Targeting Systems for Distal Locking of Intramedullary Nails* Fadi T. Jaber , Member, IEEE and Awni B. Al-Jayyousi 54 pt 0.75 in 19.1 mm 54 pt 0.75 in 19.1 mm 54 pt 0.75 in 19.1 mm 54 pt 0.75 in 19.1 mm Margin requirements for the other pages Paper size this page US Letter II. PHANTOM DESCRIPTION The main aim of the phantom introduced here is to provide a test platform for engineers to evaluate their distal locking systems without going through all the intensive surgical work that is required for IMN when performed on cadavers. This, however, does not mean that it cannot be used for training surgeons or as a demonstration model for students. It consists of a leg-tissue part, a fractured femur bone model and an IM nail. All parts are introduced in the following subsections. A. Leg-Tissue Model To emulate IMN surgery conditions as much as possible, it was decided that the part of the phantom, which represents the leg tissue should be in the supine position since it is preferred by several surgeon [28]. The tissue model (SYNBONE AG, Switzerland) is that of an entire right leg with pelvis, sacrum, fractured femur and tibia with a foam coating (Fig. 1). Figure 1. Right-thigh tissue model in the supine position. (a) lateral view, (b) medial view. The length of the leg is 850 mm. A wooden stand attached to the sacrum (Fig. 1-b) can be used for stabilizing the leg on a bench as if a patient is in the supine position prior to surgery. The foam coating at the posterior of the leg is cut open and the two ends are held together by hook and loop fasteners (Fig. 2). This provides easy-access to the inside of the leg, which houses the femur and tibia bones. B. Femur Bone Model The femur model (SYNBONE AG, Switzerland) housed in the leg model (Fig. 2) has a cortical layer and an inner foam layer that resembles cancellous bone. This type of model has been developed for orthopedic surgical education and is designed to provide the 'feel' of working with real bones with similar forces being required to drill holes. The femur has an oblique femoral mid-shaft fracture and is 450 mm in length. In addition, it has a medullary canal opening with a diameter of 9.5 mm for inserting IM nails. Following a distal hole targeting experiment, the used femur can be easily replaced. Figure 2. Posterior view of leg. The hook and loop fasteners provide easy access to the inside of the leg tissue, which houses a fractured femur shaft made from foam. C. Intramedullary Nail Two different IM nails were used as part of the phantom. These are illustrated in Fig. 3. The first nail was fabricated at the mechanical workshop of Qatar University from a stainless steel rod with a diameter of 8 mm and a length of 400 mm. The two distal holes have a diameter of 5 mm and are 40 mm apart. The second nail used is a commercial titanium alloy nail (Kanghui Medical, China). The diameter of the nail is 9 mm and its length is 340 mm. The two distal holes have diameters of 5 mm and 7 mm for the most distal one. Fig. 4 shows the two fractured parts of the femur after alignment with the stainless steel nail inserted through them via the medullary canal opening at the greater trochanter. Figure 3. The two IM nails that are used with the phantom. A custom-made stainless steel nail (top) and a titanium alloy commercial nail (bottom). Figure 4. Alignment of fractured femur model and insertion of nail. 54 pt 0.75 in 19.1 mm 54 pt 0.75 in 19.1 mm 54 pt 0.75 in 19.1 mm 54 pt 0.75 in 19.1 mm Margin requirements for the other pages Paper size this page US Letter III. DISCUSSION As mentioned in the earlier section, such phantom may have a twofold purpose. First it can be used by investigators as a test platform for assessing the accuracy and clinical applicability of distal hole targeting systems that are being developed, and second, it can have an educational role as a training tool for surgeons and a demonstration model for medicine and engineering students. The drawback of the phantom is that it does not represent the anatomy of the leg as accurately as a cadaveric leg. Nevertheless, scandals related to cadaver trafficking indicate the existence of a profit-making industry [29]. This raises ethical and moral questions regarding their use. Apart from the ethical portion of the problem, factors that were considered prior to the development of the phantom were cost, usability (i.e. ease-of-use), reusability, and storage. The cost of a cadaver ranges between $1,000 and $1,500, nevertheless, specific pieces of anatomy (e.g. a leg) may cost much more [29], [30]. In contrast, the prices of all the parts used in this work are shown in Table I. TABLE I. PRICE OF PHANTOM PARTS Part Price ($) Leg-tissue model (includes one fractured femur) 850 Commercial nail 1,265 Custom-made nail 10 Femur bone replacements 32 When comparing the price of the model proposed here with that of cadavers the cost of the IM nail is not included since the price of a cadaver or cadaveric part also does not include it. Nevertheless, Table I shows that using a custom- made nail adds only $10 to the total cost. Since the leg-tissue model includes one broken femur, $850 are sufficient for performing a single distal locking experiment. This is at least $150 less than using a cadaver or cadaveric part. The fact that the phantom is reusable reduces the cost even more. This is so because only $32 are required for each additional experiment since the femur can be easily replaced. The cost is also reduced as no special storage facilities are required for the phantom. Finally, it should be pointed out that the use of cadavers requires the presence of an orthopedic surgeon for inserting the IM nail. In contrast, this task is easily performed on the phantom by simple hook-and-loop fasteners that provide access to the interior of the thigh and the femur. A pre- drilled medullary canal in the femur also saves time and work since the nail can be inserted straight away. IV. CONCLUSION & FUTURE WORK The phantom presented in this paper has the potential of replacing cadavers for the purpose of evaluating the accuracy of distal locking techniques as well as for educational and training purposes. It offers several advantages in relation to the use of cadavers. These include lower cost, easy storage, ease-of-use, and reusability. In addition, there are no moral or ethical dilemmas associated with using such a model. The development of this phantom is part of a larger project that involves the implementation of a radiation-free distal locking system and will serve as a testing platform for it. ACKNOWLEDGMENT The authors would like to thank Dr. Rashid Mazhar (Hamad Medical Corporation, Qatar) for the commercial nail, Dr. Sumukh Khandekar (Al-Ahli Hospital, Qatar) for his invaluable advice and expertise, and the Qatar National Research Fund (QNRF) for supporting this work. REFERENCES [1] I. Kempf, A. Grosse, and G. Beck, "Closed locked intramedullary nailing. Its application to comminuted fractures of the femur," The Journal of Bone & Joint Surgery, vol. 67, pp. 709-720, 1985. [2] C. Krettek, B. Konemann, J. Mannss, P. Schandelmaier, U. Schmidt, and H. Tscherne, "Analysis of implantation-induced nail deformation and roentgen morphometric studies as the principle for an aiming device for distal interlocking nailing without roentgen image intensification," Unfallchirurg, vol. 99, pp. 671-678, 1996. [3] C. Krettek, J. Mannss, T. Miclau, P. Schandelmaier, I. Linnemann, and H. Tscherne, "Deformation of femoral nails with intramedullary insertion," Journal of Orthopaedic Research, vol. 16, pp. 572-575, 1998. [4] C. Krettek, B. Konemann, T. Miclau, P. Schlandermaier, and M. Blauth, "In vitro and in vivo radiomorphic analyses of distal screw hole position of the solid tibial nail following insertion," Clinical Biomechanics, vol. 12, pp. 198-200, 1997. [5] C. Krettek, B. Konemann, T. Miclau, R. Kolbli, T. Machreich, and H. Tscherne, "A mechanical distal aiming device for distal locking in femoral nails," Clinical Orthopaedics and Related Research, vol. 364, pp. 267–275, 1999. [6] M. MacMillan and R. H. Gross, "A simplified technique of distal femoral screw insertion for the grosse-kempf interlocking nail," Clinical Orthopaedics and Related Research, vol. 226, pp. 252–259, 1988. [7] C. J. Coetzee and E. J. v. d. Merwe, "Exposure of surgeons-intraining to radiation during intramedullary fixation of femoral shaft fractures," South African Medical Journal, vol. 81, pp. 312–314, 1992. [8] P. E. Levin, R. W. Schoen, and B. D. Browner, "Radiation exposure to the surgeon during closing interlocking intramedullary nailing," The Journal of bone and joint surgery (American volume), vol. 69, pp. 761–766, 1987. [9] S. Skejdal and S. Backe, "Interlocking medullary nails - radiation doses in distal targeting," Archives of Orthopaedic and Trauma Surgery, vol. 106, pp. 179–181, 1987. [10] I. D. Sugarman, I. Adam, and T. D. Bunker, "Radiation dosage during AO locking femoral nailing," Injury, vol. 19, pp. 336–368, 1988. [11] C. Krettek, B. Konemann, T. Miclau, R. Kolbli, T. Machreich, A. Kromm, et al., "A new mechanical aiming device for the placement of distal interlocking screws in femoral nails," Archives of Orthopaedic and Trauma Surgery, vol. 117, pp. 147-152, 1998. 54 pt 0.75 in 19.1 mm 54 pt 0.75 in 19.1 mm 54 pt 0.75 in 19.1 mm 54 pt 0.75 in 19.1 mm Margin requirements for the other pages Paper size this page US Letter [12] R. Rohilla, R. Singh, N. Magu, A. Devgun, R. Siwach, and A. Gulia, "Nail over nail technique for distal locking of femoral intramedullary nails," International Orthopaedics (SICOT), vol. 33, pp. 1107–1112, 2009. [13] U. Knothe, M. L. K. Tate, K. Klaue, and S. M. Perren, "Development and testing of a new self-locking intramedullary nail system: testing of handling aspects and mechanical properties," Injury, vol. 31, pp. 617- 626, 2000. [14] C. K. Yiannakopoulos, A. D. Kanellopoulos, C. Apostolou, E. Antonogiannakis, and D. Korres, "Distal intramedullary nail interlocking, the flag and grid technique," Journal of Orthopaedic Trauma, vol. 19, pp. 410-414, 2005. [15] R. Phillips, J. G. Griffiths, D. A. Camplin, S. Marshall, and A. M. M. A. Mohseja, "Steps towards computer assisted locking of intramedullary nails," presented at the 15th annual international conference IEEE engineering in medicine and biology society, San Diego, USA, 1993. [16] M. A. Slomczykowski, R. Hofstetter, M. Sati, C. Krettek, and L. P. Nolte, "Novel computer-assisted fluoroscopy system for intraoperative guidance: feasibility study for distal locking of femoral nails," Journal of Orthopaedic Trauma, vol. 15, pp. 122-131, 2001. [17] J. D. Goodall, "An image intensifier laser guidance system for the distal locking of an intramedullary nail," Injury, vol. 22, p. 339, 1991. [18] Z. Yaniv and L. Joskowicz, "Precise Robot-Assisted Guide Positioning for Distal Locking of Intramedullary Nails," IEEE Transaction on medical Imaging, vol. 24, pp. 624-635, 2005. [19] J. Elstrom and P. Elstrom, "Optical Distal Targeting System For An Intramedullary Nail," U.S. Patent 5 417 688, 1995. [20] W. Chu, J. Wang, S.-T. Young, and W. C. Chu, "Reducing radiation exposure in intra-medullary nailing procedures: Intra-medullary endo- transilluminating (iMET)," Injury, vol. 40, pp. 1084–1087, 2009. [21] M. Rigoberto and M. Arturo, "Assistant System for Locking Intramedullary Nails Used to Repair Fractures of the Long Bones," presented at the 4th International Conference on Electrical and Electronics Engineering (ICEEE 2007), Mexico, 2007. [22] D. S. Chan, R. B. Burris, M. Erdogan, and H. C. Sagi, "The Insertion of Intramedullary Nail Locking Screws Without Fluoroscopy: A Faster and Safer Technique " Journal of Orthopaedic Trauma, vol. 27, 2013. [23] T. Leloup, W. E. Kazzi, F. Schuind, and N. Warzée, "A Novel Technique for Distal Locking of Intramedullary Nail Based on Two Non-constrained Fluoroscopic Image and Navigation," IEEE Transaction on medical Imaging, vol. 27, pp. 1202-1212, 2008. [24] C. Neatpisarnvanit and J. Suthakorn, "Intramedullary Nail Distal Hole Axis Estimation using Blob Analysis and Hough Transform," presented at the IEEE International Conference on Robotics, Automation and Manufacturing (RAM 2006), Bangkok, Thailand, 2006. [25] S. A. Papadakis, C. Zalavras, R. Mirzayan, and L. Shepherd, "Undetected iatrogenic lesions of the anterior femoral shaft during intramedullary nailing: a cadaveric study," Journal of Orthopaedic Surgery and Research, vol. 3, 2008. [26] J. C. McLachlan, J. Bligh, P. Bradley, and J. Searle, "Teaching anatomy without cadavers," Medical Education, vol. 38, pp. 418– 424, 2004. [27] J. P. Collins, "Modern approaches to teaching and learning anatomy," BMJ, vol. 337, pp. 665-667, 2008. [28] C. M. Court-Brown, An Atlas Of Closed Nailing Of The Tibia And Femur, 1st ed. United Kingdom: Martin Dunitz, 1991, pp. 45. [29] M. Anteby, "Markets, Morals, and Practices of Trade: Jurisdictional Disputes in the U.S. Commerce in Cadavers," Administrative Science Quarterly, vol. 55, pp. 606–638, 2010. [30] J. M. Broder, "In Science's Name, Lucrative Trade in Body Parts," in The New York Times, ed. New York, USA, 2004.