• Title, Summary, Keyword: 척추케이지

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Numerical Analysis on Stress Distribution of Vertebra and Stability of Intervertebral Fusion Cage with Change of Spike Shape (척추체간 유합케이지의 스파이크형상 변화에 따른 척추체의 응력분포 및 케이지의 안정성에 대한 수치적 해석)

  • 심해영;김철생;오재윤
    • Journal of Biomedical Engineering Research
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    • v.25 no.5
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    • pp.361-367
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    • 2004
  • The axial compressive strength, relative 3-D stability and osteoconductive shape design of an intervertebral fusion cage are important biomechanical factors for successful intervertebral fusion. Changes in the stress distribution of the vertebral end plate and in cage stability due to changes in the spike shape of a newly contrived box-shaped fusion cage are investigated. In this investigation, the initial contact of the cage's spikes with the end plate and the penetration of the cage's spikes into the end plate are considered. The finite element analysis is conducted to study the effects of the cage's spike height, tip width and angle on the stress distribution of the vertebral end plate, and the micromigration of the cage in the A-P direction. The stress distribution in the end plate is examined when a normal load of 1700N is applied to the vertebra after inserting 2 cages. The micromigration of the cage is examined when a pull out load of l00N is applied in the A-P direction. The analysis results reveal that the spike tip width significantly influences the stress concentration in the end plate, but the spike height and angle do not significantly influence the stress distribution in the end plate touching the cage's spikes. In addition, the analysis results show that the micromigration of the cage can be reduced by adjusting the spike angle and spike arrangement in the A-P direction. This study proposes the optimal shape of an intervertebral fusion cage, which promotes bone fusion, reduces the stress concentration in a vertebral end plate, and increases mechanical stability.

Development and Evaluation for the Micro-Movement Structure of Interspinous (척추극돌간 미세움직임 재현 보형물의 개발 및 평가)

  • Park, Joon-Sik;Seo, Tae-Il;Bae, Jong-Suk;Yoon, Gil-Sang
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.3
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    • pp.127-131
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    • 2006
  • Existing orthopedic implants such as pedicle screw and spinal cage were designed to fix the spinal structure. But, nowadays, physicians want to rehabilitate there original functions. To achieve this request, we studied micro-movable structure for interspinous. As a first step, we designed interspinous structure by 3D CAD to join each spinous processes. Next, we simulate it with various factors such as the thickness of micro-movement structure and the design of clip. At last, we performed static compressive test to satisfy the failure load of 339N and dynamic endurance test of 1.2M cycle. As a result, we developed interspinous implant and did several surgery to evaluated its satisfaction.

Finite Element Analysis of Instrumented Posterior Lumbar Interbody Fusion Cages for Reducing Stress Shielding Effects: Comparison of the CFRP cage and Titanium cage (요추유합술에서 응력방패 현상 감소를 위한 케이지의 유한요소해석 : CFRP 케이지와 티타늄 케이지 비교 연구)

  • Kang, Kyung-Tak;Chun, Heoung-Jae;Kim, Ho-Joong;Yeom, Jin-S.;Park, Kyoung-Mi;Hwang, In-Han;Lee, Kwang-Ill
    • Composites Research
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    • v.25 no.4
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    • pp.98-104
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    • 2012
  • In recent years, degenerative spinal instability has been effectively treated with a cage. However, little attention is focused on the stiffness of the cage. Recent advances in the medical implant industry have resulted in the use of medical carbon fiber reinforced polymer (CFRP) cages. The biomechanical advantages of using different cage material in terms of stability and stresses in bone graft are not fully understood. A previously validated three-dimensional, nonlinear finite element model of an intact L2-L5 segment was modified to simulate posterior interbody fusion cages made of CFRP and titanium at the L4-L5 disc with pedicle screw, to investigate the effect of cage stiffness on the biomechanics of the fused segment in the lumbar region. From the results, it could be found that the use of a CFRP cage would not only reduce stress shielding, but it might also have led to increased bony fusion.

Testing Evaluation for Stand-Alone Cervical Cage (경추용 자립형 케이지의 실험적 평가)

  • Baek, Myong-Hyun;Lee, Mun-Hwan
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.11
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    • pp.937-941
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    • 2016
  • Stand-alone cervical cage consists of a PEEK body, Ti plate, and screw, which are configured as a single-piece. Through a single operation, this implantable medical device is capable of completely fixing the cervical vertebral body. For example, instead of a plate, which is normally used, the intervertebral disc is removed and replaced with a cervical cage. It should be noted that in Korea, KFDA guidelines for a stand-alone cervical cage have not yet been suggested. Therefore, the aim of this study is to present the systematic study of the static compression test, static torsion test, dynamic compression test, and expulsion test. Further, the test method is designed to refer to the ASTM standard and relative literature.