UPSI Digital Repository (UDRep)
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UPSI Digital Repository (UDRep)
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| Abstract : Universiti Pendidikan Sultan Idris |
| Pedicle screw is made from titanium alloy which gives support in the treatment of specific condition like lumbar, acute and chronic instabilities or deformities of thoracic, sacral spine. Mostly, the screw comes with rods act as connector, nuts, sleeves and plates. As a system, it increases the rigidity and holds the bone in placed while the bone heals itself over time. Over the years, many researchers have studied the pullout strength and the bending strength of pedicle screw. They found out that factors like core design, thread design, geometry and insertion techniques influenced the strength in pullout and bending. Failure of a screw is unavoidable. Sometime breakage happened at the neck or at the radial hole of pedicle screw due to high local stress. Thus, this project focused on the finding the most optimize diameter and position of radial in cylindrical screw to increase its bending strength. The pedicle screw inserted 40�mm into cylindrical block as a replacement for real human bone. It was then validated using Ansys software after gone through several simulation until the error become less than 10%. As a validated model, it was modified into pedicle screw with 2 radial holes varied diameter of 1.0�mm, 1.5�mm and 2.0�mm at 3 different position of radial hole. It was given bending moment of 1.29�Nm for starters and increase 0.3�Nm until the pedicle screw reached the yield stress at 790�Mpa. The head fixed at all directions and bending moment applied at tip of pedicle screw. As a result, high stress mostly distributed around the radial holes. All of the proposed designs able to withstand bending moment of 1.29�Nm?2.79�Nm while maintaining its original shape. Unlike the original pedicle screw, it can only resist bending moment at best 2.03�Nm before it broke. Finally, the most optimized diameter and position of radial hole was 1.0�mm at parallel positioned with improvement of 10.75% and 21.51% better than 1.5�mm and 2.0�mm respectively despite any position of radial hole. ? 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. |
| References |
Alvine, G. F., Swain, J. M., Asher, M. A., & Burton, D. C. (2004). Treatment of thoracolumbar burst fractures with variable screw placement or isola instrumentation and arthrodesis: Case series and literature review. Journal of Spinal Disorders and Techniques, 17(4), 251-264. doi:10.1097/01.bsd.0000095827.98982.88 Amaritsakul, Y., Chao, C. -., & Lin, J. (2014). Biomechanical evaluation of bending strength of spinal pedicle screws, including cylindrical, conical, dual core and double dual core designs using numerical simulations and mechanical tests. Medical Engineering and Physics, 36(9), 1218-1223. doi:10.1016/j.medengphy.2014.06.014 Andersen, T., Christensen, F. B., Niedermann, B., Helmig, P., Høy, K., Hansen, E. S., & Bünger, C. (2009). Impact of instrumentation in lumbar spinal fusion in elderly patients: 71 patients followed for 2-7 years. Acta Orthopaedica, 80(4), 445-450. doi:10.3109/17453670903170505 Burval, D. J., McLain, R. F., Milks, R., & Inceoglu, S. (2007). Primary pedicle screw augmentation in osteoporotic lumbar vertebrae: Biomechanical analysis of pedicle fixation strength. Spine, 32(10), 1077-1083. doi:10.1097/01.brs.0000261566.38422.40 Butler, T. E., Asher, M. A., Jayaraman, G., Nunley, P. D., & Robinson, R. G. (1994). The strength and stiffness of thoracic implant anchors in osteoporotic spines. Spine, 19(17), 1956-1962. doi:10.1097/00007632-199409000-00016 Chang, M. -., Liu, C. -., & Chen, T. -. (2008). Polymethylmethacrylate augmentation of pedicle screw for osteoporotic spinal surgery: A novel technique. Spine, 33(10), E317-E324. doi:10.1097/BRS.0b013e31816f6c73 Chao, C. -., Lin, J., Putra, S. T., & Hsu, C. -. (2010). A neurogenetic approach to a multiobjective design optimization of spinal pedicle screws. Journal of Biomechanical Engineering, 132(9) doi:10.1115/1.4001887 Chen, H. -., Lai, Y. -., Chen, W. -., Chen, J. -., Chang, C. -., Chen, Y. -., . . . Cheng, C. -. (2015). Effect of different radial hole designs on pullout and structural strength of cannulated pedicle screws. Medical Engineering and Physics, 37(8), 746-751. doi:10.1016/j.medengphy.2015.05.004 Cook, S. D., Salkeld, S. L., Stanley, T., Faciane, A., & Miller, S. D. (2004). Biomechanical study of pedicle screw fixation in severely osteoporotic bone. Spine Journal, 4(4), 402-408. doi:10.1016/j.spinee.2003.11.010 DeWald, C. J., & Stanley, T. (2006). Instrumentation-related complications of multilevel fusions for adult spinal deformity patients over age 65: Surgical considerations and treatment options in patients with poor bone quality. Spine, 31(19 SUPPL.), S144-S151. doi:10.1097/01.brs.0000236893.65878.39 Esses, S. I., Botsford, D. J., Huler, R. J., & Rauschning, W. (1991). Surgical anatomy of the sacrum: A guide for rational screw fixation. Spine, 16(6S), S283-S288. doi:10.1097/00007632-199106001-00021 Gaines R.W., J. (2000). The use of pedicle-screw internal fixation for the operative treatment of spinal disorders. Journal of Bone and Joint Surgery, 82(10), 1458-1476. doi:10.2106/00004623-200010000-00013 Hadjipavlou, A. G., Katonis, P. G., Tzermiadianos, M. N., Tsoukas, G. M., & Sapkas, G. (2003). Principles of management of osteometabolic disorders affecting the aging spine. European Spine Journal, 12(SUPPL. 2), S113-S131. doi:10.1007/s00586-003-0600-5 Halvorson, T. L., Kelley, L. A., Thomas, K. A., Whitecloud, T. S., & Cook, S. D. (1994). Effects of bone mineral density on pedicle screw fixation. Spine, 19(21), 2415-2420. doi:10.1097/00007632-199411000-00008 Hirano, T., Hasegawa, K., Washio, T., Hara, T., & Takahashi, H. (1998). Fracture risk during pedicle screw insertion in osteoporotic spine. Journal of Spinal Disorders, 11(6), 493-497. doi:10.1097/00002517-199812000-00007 Kanis, J. A., Melton, L. J.,III, Christiansen, C., Johnston, C. C., & Khaltaev, N. (1994). The diagnosis of osteoporosis. Journal of Bone and Mineral Research, 9(8), 1137-1141. doi:10.1002/jbmr.5650090802 Kim, Y. -., Choi, W. -., & Rhyu, K. -. (2012). Assessment of pedicle screw pullout strength based on various screw designs and bone densities - an ex vivo biomechanical study. Spine Journal, 12(2), 164-168. doi:10.1016/j.spinee.2012.01.014 Lill, C. A., Schneider, E., Goldhahn, J., Haslemann, A., & Zeifang, F. (2006). Mechanical performance of cylindrical and dual core pedicle screws in calf and human vertebrae. Archives of Orthopaedic and Trauma Surgery, 126(10), 686-694. doi:10.1007/s00402-006-0186-6 Patel, P. S. D., Shepherd, D. E. T., & Hukins, D. W. L. (2010). The effect of screw insertion angle and thread type on the pullout strength of bone screws in normal and osteoporotic cancellous bone models. Medical Engineering and Physics, 32(8), 822-828. doi:10.1016/j.medengphy.2010.05.005 Ponnusamy, K. E., Iyer, S., Gupta, G., & Khanna, A. J. (2011). Instrumentation of the osteoporotic spine: Biomechanical and clinical considerations. Spine Journal, 11(1), 54-63. doi:10.1016/j.spinee.2010.09.024 Shea, T. M., Laun, J., Gonzalez-Blohm, S. A., Doulgeris, J. J., Lee, W. E., Aghayev, K., & Vrionis, F. D. (2014). Designs and techniques that improve the pullout strength of pedicle screws in osteoporotic vertebrae: Current status. BioMed Research International, 2014 doi:10.1155/2014/748393 |
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