Spring rod를 사용한 척추경 나사못과 동반 시술된 Flexible cage의 생체역학적 효과
Biomechanical Efficacy of a Combined Flexible Cage with Pedicle Screws with Spring rods: A Finite Element Analysis
2
조회
0
다운로드
1
인용
0
참고문헌
키워드
초록
Recently, flexible cages have been introduced in an attempt to absorb and reduce the abnormal load transfer along the anterior parts of the spine. They are designed to be used with the pedicle screw systems to allow some mobility at the index level while containing ROM at the adjacent level. In this study, a finite element (FE) study was performed to assess biomechanical efficacies of the flexible cage when combined with pedicle screws with flexible rods. The post-operated models were constructed by modifying the L4-5 of a previously-validated 3-D FE model of the intact lumbar spine (L2-S1): (1) Type 1, flexible cage only; (2) Type 2, pedicle screws with flexible rods; (3) Type 3, interbody fusion cage plus pedicle screws with rigid rods; (4) Type 4, interbody fusion cage plus Type 2; (5) Type 5, Type 1 plus Type 2. Flexion/extension of 10 Nm with a compressive follower load of 400N was applied. As compared to the Type 3 (62~65%) and Type 4 (59~62%), Type 5 (53~55%) was able to limit the motion at the operated level effectively, despite moderate reduction at the adjacent level. It was also able to shift the load back to the anterior portions of the spine thus relieving excessively high posterior load transfer and to reduce stress on the endplate by absorbing the load with its flexible shape design features. The likelihood of component failure of flexble cage remained less than 30% regardless of loading conditions when combined with pedicle screws with flexible rods. Our study demonstrated that flexible cages when combined with posterior dynamic system may help reduce subsidence of cage and degeneration process at the adjacent levels while effectively providing stability at the operated level.
Abstract
Recently, flexible cages have been introduced in an attempt to absorb and reduce the abnormal load transfer along the anterior parts of the spine. They are designed to be used with the pedicle screw systems to allow some mobility at the index level while containing ROM at the adjacent level. In this study, a finite element (FE) study was performed to assess biomechanical efficacies of the flexible cage when combined with pedicle screws with flexible rods. The post-operated models were constructed by modifying the L4-5 of a previously-validated 3-D FE model of the intact lumbar spine (L2-S1): (1) Type 1, flexible cage only; (2) Type 2, pedicle screws with flexible rods; (3) Type 3, interbody fusion cage plus pedicle screws with rigid rods; (4) Type 4, interbody fusion cage plus Type 2; (5) Type 5, Type 1 plus Type 2. Flexion/extension of 10 Nm with a compressive follower load of 400N was applied. As compared to the Type 3 (62~65%) and Type 4 (59~62%), Type 5 (53~55%) was able to limit the motion at the operated level effectively, despite moderate reduction at the adjacent level. It was also able to shift the load back to the anterior portions of the spine thus relieving excessively high posterior load transfer and to reduce stress on the endplate by absorbing the load with its flexible shape design features. The likelihood of component failure of flexble cage remained less than 30% regardless of loading conditions when combined with pedicle screws with flexible rods. Our study demonstrated that flexible cages when combined with posterior dynamic system may help reduce subsidence of cage and degeneration process at the adjacent levels while effectively providing stability at the operated level.
참고문헌 (20)
- A.S. Hilibrand, "Degenrative lumbar stenosis:Diagnosis and management", J Am Acad Orthop Surg, 7(4), pp.239~249 (1999)
- K.C. Choi, "Biomechanical comparison of anterior lumbar interbody fusion: stand-alone interbody cage versus interbody cage with pedicle screw fixation - a finite element analysis", BMC Musculoskeletal Disorders, 14(220) (2013)
- T. Akamura, "Adjacent segment motion after a simulated lumbar fusion in different sagittal alignment", Spine, 28, pp.1560~1566 (2003)
- D. H. Chow, "Effects of short anterior lumbar interbody fusion on biomechanics of neighboring unfused segment", Spine, 21, pp.549~555 (1996)
- D. C. Kim, "Preliminary report on usefulness of adjacent interpinous stabilization using interspinous spacer combined with posterior lumbosacral spinal fusion in degenerative lumbar disease", Korean J Spine, 9(3), pp.149~155 (2009)
- Y. H. Kim, "Biomechanical efficacies of a flexible cage combined with pedicle screws with flexible rods", International Society for the Advancement of Spine Surgery, Poster, (349) (2013)
- U.S. Food, "Classification discussion, pedicle screw spinal systems (Certain uses - Class III indications for use", Meeting of the Orthopaedic and Rehabilitation Devices Panel of the Medical Devices Advisory Committee, pp.1~61 (2013)
- W. M. Chen, "In situ contact analysis of the prosthesis components of Prodisc-L in lumbar spine following total disc replacement", Spine, 34(20), pp.716~723 (2009)
- Yeong-Hyeon Kim, "Biomechanical Efficacy of a Combined Interspinous Fusion System with a Lumbar Interbody Fusion Cage", International Journal of Precision Engineering and Manufacturing, 16(5), pp.997~1001 (2015), 한국정밀공학회
- T. Zander, "Estimation of muscle forces in the lumbar spine during upper-body inclination", Clinical Biomechanics, 16, pp.73~80 (2001)
- V. K. Goel, "Interlaminal shear stresses and laminae separation in a disk : Finite element analysis of the L-L4 motion segment subjected to axial compressive loads", Spine, 20, pp.689~698 (1995)
- S. A. Shirazi-Adl, "Stress analysis of the lumbar disc-body unit in compression a treedimensional nonlinear finite element study", Spine, 9, pp.120~134 (1984)
- M. Sharma, "Role of ligaments and facets in lumbar spinal stability", Spine, 20, pp.887~900 (1995)
- T. H. Smit, "Structure and Function of Vertebral Trabecular bone", Spine, 22, pp.2823~2833 (1997)
- 안윤호, "Posterior Dynamic Stabilization System의 요추거동에 대한 생체역학적 분석", 의공학회지, 29(2), pp.139~145 (2008), 대한의용생체공학회
- 김영현, "척추경나사못을 이용한 유합술과 동반 시술된 극돌기간 삽입기구의 생체역학적 연구", 의공학회지, 36(6), pp.276~282 (2015), 대한의용생체공학회
- M.M. Panjabi, "Roundtables in Spine Surgery; Spine Biomechanics", pp.45~58 (2008), Quality Medical Publishing
- 김영현, "유한요소 해석을 이용한 정형용 흉·요추 보조기의 형태에 따른 생체역학적 분석", 재활복지공학회논문지, 6(1), pp.45~50 (2012), 한국재활복지공학회
- D.S Brodke, "Anterior thoracolumbar instrumentation: Stiffness and load sharing characteristics of plate and rod systems", Spine, 28(16), pp.1794~1801 (2003)
- M. Moumene, "Biomechanical comparison of rigid vs. semi-rigid rods in spinal fusion constructs: A finite element study", Spine Arthroplasty Society, Abstract, (82), pp.23~24 (2007)