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Zeng HZ, Zheng LD, Xu ML, Zhu SJ, Zhou L, Candito A, Wu T, Zhu R, Chen Y. Biomechanical effect of age-related structural changes on cervical intervertebral disc: A finite element study. Proc Inst Mech Eng H 2022; 236:1541-1551. [DOI: 10.1177/09544119221122007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Previous literature has investigated the biomechanical response of healthy and degenerative discs, but the biomechanical response of suboptimal healthy intervertebral discs received less attention. The purpose was to compare the biomechanical responses and risk of herniation of young healthy, suboptimal healthy, and degenerative intervertebral discs. A cervical spine model was established and validated using the finite element method. Suboptimal healthy, mildly, moderately, and severely degenerative disc models were developed. Disc height deformation, range of motion, intradiscal pressure, and von Mises stress in annulus fibrosus were analyzed by applying a moment of 4 Nm in flexion, extension, lateral bending, and axial rotation with 100 N compressive loads. Disc height deformation in young healthy, suboptimal healthy, mildly, moderately, and severely degenerative discs was 40%, 37%, 21%, 12%, and 8%, respectively. The decreasing order of the range of motion was young healthy spine > suboptimal healthy spine > mildly degenerative spine > moderately degenerative spine > severely degenerative spine. The mean stress of annulus ground substance in the suboptimal healthy disc was higher than in the young healthy disc. The mean stress of inter-lamellar matrix and annulus ground substance in moderately and severely degenerative discs was higher than in other discs. Age-related structural changes and degenerative changes increased the stiffness and reduced the elastic deformation of intervertebral discs. Decreased range of motion due to the effects of aging or degeneration on the intervertebral disc, may cause compensation of adjacent segments and lead to progressive degeneration of multiple segments. The effect of aging on the intervertebral disc increased the risk of annulus fibrosus damage from the biomechanical point of view. Moderately and severely degenerative discs may have a higher risk of herniation due to the higher risk of damage and layers separation of annulus fibrosus caused by increased stress in the annulus ground substance and inter-lamellar matrix.
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Affiliation(s)
- Hui-zi Zeng
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of the Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Liang-dong Zheng
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of the Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Meng-lei Xu
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of the Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Shi-jie Zhu
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of the Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Liang Zhou
- Shanghai University of Medicine & Health Sciences, Shanghai, China
| | - Antonio Candito
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK
| | - Tao Wu
- Shanghai University of Medicine & Health Sciences, Shanghai, China
| | - Rui Zhu
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of the Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
- Shanghai Clinical Research Center for Ageing and Medicine, Shanghai, China
| | - Yuhang Chen
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK
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Kumar S, Peterson TR. Moonshots for aging. ACTA ACUST UNITED AC 2020; 5:239-246. [PMID: 33344796 PMCID: PMC7740370 DOI: 10.3233/nha-190064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
As the global population ages, there is increased interest in living longer and improving one’s quality of life in later years. However, studying aging – the decline in body function – is expensive and time-consuming. And despite research success to make model organisms live longer, there still aren’t really any feasible solutions for delaying aging in humans. With space travel, scientists and engineers couldn’t know what it would take to get to the moon. They had to extrapolate from theory and shorter-range tests. Perhaps with aging, we need a similar moonshot philosophy. And though “shot” might imply medicine, perhaps we need to think beyond medical interventions. Like the moon once was, we seem a long way away from provable therapies to increase human healthspan (the healthy period of one’s life) or lifespan (how long one lives). This review therefore focuses on radical proposals. We hope it might stimulate discussion on what we might consider doing significantly differently than ongoing aging research.
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Affiliation(s)
- Sandeep Kumar
- Department of Internal Medicine, Division of Bone and Mineral Diseases, Department of Genetics, Institute for Public Health, Washington University School of Medicine, BJC Institute of Health, MO, USA
| | - Timothy R Peterson
- Department of Internal Medicine, Division of Bone and Mineral Diseases, Department of Genetics, Institute for Public Health, Washington University School of Medicine, BJC Institute of Health, MO, USA
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