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Zhao G, Jiang Z, Chen E, Ma T, Wu J, Song C, Li W. Biomechanical investigation of a customized interspinous spacer system in the treatment of degenerative disc diseases: A finite element analysis. Clin Biomech (Bristol, Avon) 2024; 116:106270. [PMID: 38776646 DOI: 10.1016/j.clinbiomech.2024.106270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 05/15/2024] [Accepted: 05/17/2024] [Indexed: 05/25/2024]
Abstract
BACKGROUND A novel interspinous fixation system based on anatomical parameters and incorporating transfacetopedicular screws, was developed to treat degenerative disc diseases. The biomechanical characteristics of the novel system were evaluated using finite element analysis in comparison to other classical interspinous spacers. METHODS The L1-S1 lumbar spine finite element models were surgically implanted with the novel system, Coflex and DIAM devices at the L4/L5 segment to assess the range of motion, the pression distribution of intervertebral disc, the peak stresses on the spinous process and implant during various motions. FINDINGS Range of motions of the L4/L5 surgical segment were reduced by 29.13%, 61.27%, 77.35%, 33.33%, and the peak stresses of intervertebral disc were decreased by 36.82%, 67.31%, 73.00%, 69.57% for the novel system in flexion, extension, lateral bending, and axial rotation when compared with the Coflex, and they were declined by 34.53%, 57.86%, 75.81%, 25.21%; 36.22%, 67.31%, 75.01%, 71.40% compared with DIAM. The maximum stresses of the spinous process were 29.93 MPa, 24.66 MPa, 14.45 MPa, 24.37 MPa in the novel system, and those of Coflex and DIAM were 165.3 MPa, 109 MPa, 84.79 MPa, 47.66 MPa and 52.59 MPa, 48.78 MPa, 50.27 MPa, 44.16 MPa during the same condition. INTERPRETATION Compared to other interspinous spacer devices, the novel interspinous fixation system demonstrated excellent stability, effectively distributing load on the intervertebral disc, and reducing the risk of spinous process fractures. The personalized design of the novel interspinous fixation system could be a viable option for treating degenerative disc diseases.
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Affiliation(s)
- Gaiping Zhao
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China.
| | - Zhehua Jiang
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Eryun Chen
- School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Tong Ma
- Department of Bone and Joint Surgery, Yangpu Hospital, School of Medicine, Tongji University, Shanghai 200090, China.
| | - Jie Wu
- Key Laboratory of Hydrodynamics, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Chengli Song
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China
| | - Weiqi Li
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, PR China
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Xi Z, Xie Y, Sun S, Wang N, Chen S, Kang X, Li J. Stepwise reduction of bony density in patients induces a higher risk of annular tears by deteriorating the local biomechanical environment. Spine J 2024; 24:831-841. [PMID: 38232914 DOI: 10.1016/j.spinee.2023.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 11/15/2023] [Accepted: 12/27/2023] [Indexed: 01/19/2024]
Abstract
BACKGROUND CONTEXT The relationship between osteoporosis and intervertebral disc degeneration (IDD) remains unclear. Considering that annular tear is the primary phenotype of IDD in the lumbar spine, the deteriorating local biomechanical environment may be the main trigger for annular tears. PURPOSE To investigate whether poor bone mineral density (BMD) in the vertebral bodies may increase the risk of annular tears via the degradation of the local biomechanical environment. STUDY DESIGN This study was a retrospective investigation with relevant numerical mechanical simulations. PATIENT SAMPLE A total of 64 patients with low back pain (LBP) and the most severe IDD in the L4-L5 motion segment were enrolled. OUTCOME MEASURES Annulus integration status was assessed using diffusion tensor fibre tractography (DTT). Hounsfield unit (HU) values of adjacent vertebral bodies were employed to determine BMD. Numerical simulations were conducted to compute stress values in the annulus of models with different BMDs and body positions. METHODS The clinical data of the 64 patients with low back pain were collected retrospectively. The BMD of the vertebral bodies was measured using the HU values, and the annulus integration status was determined according to DTT. The data of the patients with and without annular tears were compared, and regression analysis was used to identify the independent risk factors for annular tears. Furthermore, finite element models of the L4-L5 motion segment were constructed and validated, followed by estimating the maximum stress on the post and postlateral interfaces between the superior and inferior bony endplates (BEPs) and the annulus. RESULTS Patients with lower HU values in their vertebral bodies had significantly higher incidence rates of annular tears, with decreased HU values being an independent risk factor for annular tears. Moreover, increased stress on the BEP-annulus interfaces was associated with a stepwise reduction of bony density (ie, elastic modulus) in the numerical models. CONCLUSIONS The stepwise reduction of bony density in patients results in a higher risk of annular tears by deteriorating the local biomechanical environment. Thus, osteoporosis should be considered to be a potential risk factor for IDD biomechanically.
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Affiliation(s)
- Zhipeng Xi
- Department of Orthopedics, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100th. Shizi Street , Nanjing, 210028, Jiangsu Province, P.R. China; Department of Orthopedics, Traditional Chinese Medicine Hospital of Ili Kazak Autonomous Prefecture, 2th. Jiankang Street, Yining, 835000, Xinjiang Uighur Autonomous Region, P.R. China
| | - Yimin Xie
- Department of Orthopedics, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100th. Shizi Street , Nanjing, 210028, Jiangsu Province, P.R. China
| | - Shenglu Sun
- Department of Imaging, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100th. Shizi Street , Nanjing, 210028, Jiangsu Province, P.R. China
| | - Nan Wang
- Department of Orthopedics, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100th. Shizi Street , Nanjing, 210028, Jiangsu Province, P.R. China
| | - Shuang Chen
- Department of Orthopedics, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100th. Shizi Street , Nanjing, 210028, Jiangsu Province, P.R. China
| | - Xiong Kang
- Department of Orthopedics, Traditional Chinese Medicine Hospital of Ili Kazak Autonomous Prefecture, 2th. Jiankang Street, Yining, 835000, Xinjiang Uighur Autonomous Region, P.R. China
| | - Jingchi Li
- Department of Orthopedics, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, No.182, Chunhui Rd, Longmatan District, Luzhou, 646000, Sichuan Province, P.R. China.
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Ardatov O, Pachaleva J, Aleksiuk V, Maknickas A, Uzieliene I, Vaiciuleviciute R, Bernotiene E. Modeling the Effect of Annulus Fibrosus Stiffness on the Stressed State of a Vertebral L1 Body and Nucleus Pulposus. Bioengineering (Basel) 2024; 11:305. [PMID: 38671727 PMCID: PMC11047532 DOI: 10.3390/bioengineering11040305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 04/28/2024] Open
Abstract
The investigation examines the transference of stiffness from intervertebral discs (IVDs) to the lumbar body of the L1 vertebra and the interactions among adjacent tissues. A computational model of the vertebra was developed, considering parameters such as cortical bone thickness, trabecular bone elasticity, and the nonlinear response of the nucleus pulposus to external loading. A nonlinear dynamic analysis was performed, revealing certain trends: a heightened stiffness of the annulus fibrosus correlates with a significant reduction in the vertebral body's ability to withstand external loading. At a supplied displacement of 6 mm, the vertebra with a degenerative disc reached its yielding point, whereas the vertebrae with a healthy annulus fibrosus exhibited a strength capacity exceeding 20%. The obtained findings and proposed methodology are potentially useful for biomedical engineers and clinical specialists in evaluating the condition of the annulus fibrosus and predicting its influence on the bone components of the spinal system.
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Affiliation(s)
- Oleg Ardatov
- Faculty of Mechanics, Vilnius Gediminas Technical University, LT-10223 Vilnius, Lithuania;
| | - Jolita Pachaleva
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, LT-08410 Vilnius, Lithuania; (J.P.); (V.A.); (I.U.); (R.V.); (E.B.)
| | - Viktorija Aleksiuk
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, LT-08410 Vilnius, Lithuania; (J.P.); (V.A.); (I.U.); (R.V.); (E.B.)
| | - Algirdas Maknickas
- Faculty of Mechanics, Vilnius Gediminas Technical University, LT-10223 Vilnius, Lithuania;
| | - Ilona Uzieliene
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, LT-08410 Vilnius, Lithuania; (J.P.); (V.A.); (I.U.); (R.V.); (E.B.)
| | - Raminta Vaiciuleviciute
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, LT-08410 Vilnius, Lithuania; (J.P.); (V.A.); (I.U.); (R.V.); (E.B.)
| | - Eiva Bernotiene
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, LT-08410 Vilnius, Lithuania; (J.P.); (V.A.); (I.U.); (R.V.); (E.B.)
- Faculty of Fundamental Sciences, Vilnius Gediminas Technical University, LT-10221 Vilnius, Lithuania
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Khalaf K, Nikkhoo M, Shams S, Niu CC, Cheng CH. Impact of osteoporosis and Cement-Augmented fusion on adjacent spinal levels Post-Fusion Surgery: Patient-Specific finite element analysis. J Biomech 2024; 166:112070. [PMID: 38569456 DOI: 10.1016/j.jbiomech.2024.112070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 03/26/2024] [Accepted: 03/30/2024] [Indexed: 04/05/2024]
Abstract
Cement-augmentation is a technique commonly used during posterior lumbar instrumented fusion (PLIF) to reinforce compromised osteoporotic vertebral bone, minimize the risk of loosening screws, enhance stability, and improve overall surgical outcomes. In this study, we introduce a novel segmented vertebral body regional modeling approach to investigate the effects of osteoporosis and cement-augmented lumbar fusion on disc biomechanics at spinal levels adjacent to the fused vertebrae. Using our previously validated personalized-poroelastic-osteoligamentous FE model of the spine, fusion was simulated at L4-L5, and the biomechanics of adjacent levels were studied for 30 patients (non-osteoporotic patients (N = 15), osteoporotic patients (N = 15)). PLIF models, with and without cement-augmentation, were developed and compared after an 8 h-rest period (200 N), following a 16 h-cyclic compressive loading of 500-1000 N (40 and 20 min, respectively). Movement in different directions (flexion/ extension/ lateral bending/ axial rotation) was simulated using 10Nm moment before and after cyclic loading. The material mapping algorithm was validated by comparing the results of voxel-based and parametric models. The FE cement-augmented models, subject to daily activity loading, demonstrated significant differences in disc height loss and fluid loss as compared to non-cemented models. The calculated axial stress and fiber strain values were also significantly higher for these models. This work demonstrates that although osteoporosis does not significantly alter the time-dependent characteristics of adjacent IVDs post-surgery, cement-augmentation increases the risk of adjacent segment disease (ASD) incidence. A holistic understanding of the trade-offs and long-term complex interplay between structural reinforcement modalities, including cement augmentation, and altered biomechanics warrants further investigation.
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Affiliation(s)
- Kinda Khalaf
- College of Medicine and Health Sciences, Khalifa University of Science and Technology, and Health Engineering Innovation Center, Abu Dhabi, United Arab Emirates.
| | - Mohammad Nikkhoo
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan; Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Shohreh Shams
- Department of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Chi-Chien Niu
- Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan; Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Chih-Hsiu Cheng
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan.
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Huang F, Huang G, Jia J, Lu S, Li J. Intraoperative capsule protection can reduce the potential risk of adjacent segment degeneration acceleration biomechanically: an in silico study. J Orthop Surg Res 2024; 19:143. [PMID: 38365801 PMCID: PMC10870541 DOI: 10.1186/s13018-024-04550-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/09/2024] [Indexed: 02/18/2024] Open
Abstract
BACKGROUND The capsule of the zygapophyseal joint plays an important role in motion segmental stability maintenance. Iatrogenic capsule injury is a common phenomenon in posterior approach lumbar interbody fusion operations, but whether this procedure will cause a higher risk of adjacent segment degeneration acceleration biomechanically has yet to be identified. METHODS Posterior lumbar interbody fusion (PLIF) with different grades of iatrogenic capsule injury was simulated in our calibrated and validated numerical model. By adjusting the cross-sectional area of the capsule, different grades of capsule injury were simulated. The stress distribution on the cranial motion segment was computed under different loading conditions to judge the potential risk of adjacent segment degeneration acceleration. RESULTS Compared to the PLIF model with an intact capsule, a stepwise increase in the stress value on the cranial motion segment can be observed with a step decrease in capsule cross-sectional areas. Moreover, compared to the difference between models with intact and slightly injured capsules, the difference in stress values was more evident between models with slight and severe iatrogenic capsule injury. CONCLUSION Intraoperative capsule protection can reduce the potential risk of adjacent segment degeneration acceleration biomechanically, and iatrogenic capsule damage on the cranial motion segment should be reduced to optimize patients' long-term prognosis.
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Affiliation(s)
- Fei Huang
- Department of Orthopedics, Meishan Hospital of Traditional Chinese Medicine, Meishan, China
| | - Gang Huang
- Luzhou Key Laboratory of Orthopedic Disorders, Southwest Medical University, No. 182, Chunhui Road, Luzhou, 646000, Sichuan Province, People's Republic of China
| | - Junpengli Jia
- Luzhou Key Laboratory of Orthopedic Disorders, Southwest Medical University, No. 182, Chunhui Road, Luzhou, 646000, Sichuan Province, People's Republic of China
| | - Shihao Lu
- Department of Orthopedics, Changzheng Hospital Affiliated to the Naval Medical University, Xiangyin Road, Shanghai, 200433, People's Republic of China.
| | - Jingchi Li
- Department of Orthopedics, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, No. 182, Chunhui Road, Longmatan District, Luzhou, 646000, Sichuan Province, People's Republic of China.
- Luzhou Key Laboratory of Orthopedic Disorders, Southwest Medical University, No. 182, Chunhui Road, Luzhou, 646000, Sichuan Province, People's Republic of China.
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Liu Y, Zhang Q, Ji N, Wang J, Li J, Du J, Zhao J, Ouyang P, Qin J, Li H, Wang D. Stability simulation analysis of targeted puncture in L4/5 intervertebral space for PELD surgery. Front Bioeng Biotechnol 2024; 11:1298914. [PMID: 38260730 PMCID: PMC10800398 DOI: 10.3389/fbioe.2023.1298914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 12/20/2023] [Indexed: 01/24/2024] Open
Abstract
Introduction: The application prospects of percutaneous endoscopic lumbar discectomy (PELD) as a minimally invasive spinal surgery method in the treatment of lumbar disc herniation are extensive. This study aims to find the optimal entry angle for the trephine at the L4/5 intervertebral space, which causes less lumbar damage and has greater postoperative stability. To achieve this, we conduct a three-dimensional simulated analysis of the degree of damage caused by targeted puncture-based trephine osteotomy on the lumbar spine. Methods: We gathered clinical CT data from patients to construct a lumbar model. This model was used to simulate and analyze the variations in trephine osteotomy volume resulting from targeted punctures at the L4/5 interspace. Furthermore, according to these variations in osteotomy volume, we created Finite Element Analysis (FEA) models specifically for the trephine osteotomy procedure. We then applied mechanical loads to conduct range of motion and von Mises stress analyses on the lumbar motion unit. Results: In percutaneous endoscopic interlaminar discectomy, the smallest osteotomy volume occurred with a 20° entry angle, close to the base of the spinous process. The volume increased at 30° and reached its largest at 40°. In percutaneous transforaminal endoscopic discectomy, the largest osteotomy volume was observed with a 50° entry angle, passing through the facet joints, with smaller volumes at 60° and the smallest at 70°. In FEA, M6 exhibited the most notable biomechanical decline, particularly during posterior extension and right rotation. M2 and M3 showed significant differences primarily in rotation, whereas the differences between M3 and M4 were most evident in posterior extension and right rotation. M5 displayed their highest stress levels primarily in posterior extension, with significant variations observed in right rotation alongside M4. Conclusion: The appropriate selection of entry sites can reduce lumbar damage and increase stability. We suggest employing targeted punctures at a 30° angle for PEID and at a 60° angle for PTED at the L4/5 intervertebral space. Additionally, reducing the degree of facet joint damage is crucial to enhance postoperative stability in lumbar vertebral motion units.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Haopeng Li
- Department of Orthopedics, The Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Dong Wang
- Department of Orthopedics, The Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China
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Koga M, Kim B, Lintz M, Kirnaz S, Goldberg JL, Hussain I, Medary B, Meyers KN, Maher SA, Härtl R, Bonassar LJ. Finite element modeling to predict the influence of anatomic variation and implant placement on performance of biological intervertebral disc implants. JOR Spine 2023; 6:e1307. [PMID: 38156058 PMCID: PMC10751973 DOI: 10.1002/jsp2.1307] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 11/07/2023] [Accepted: 11/10/2023] [Indexed: 12/30/2023] Open
Abstract
Background Tissue-engineered intervertebral disc (TE-IVD) constructs are an attractive therapy for treating degenerative disc disease and have previously been investigated in vivo in both large and small animal models. The mechanical environment of the spine is notably challenging, in part due to its complex anatomy, and implants may require additional mechanical support to avoid failure in the early stages of implantation. As such, the design of suitable support implants requires rigorous validation. Methods We created a FE model to simulate the behavior of the IVD cages under compression specific to the anatomy of the porcine cervical spine, validated the FE model using an animal model, and predicted the effects of implant location and vertebral angle of the motion segment on implant behavior. Specifically, we tested anatomical positioning of the superior vertebra and placement of the implant. We analyzed corresponding stress and strain distributions. Results Results demonstrated that the anatomical geometry of the porcine cervical spine led to concentrated stress and strain on the posterior side of the cage. This stress concentration was associated with the location of failure of the cages reported in vivo, despite superior mechanical properties of the implant. Furthermore, placement of the cage was found to have profound effects on migration, while the angle of the superior vertebra affected stress concentration of the cage. Conclusions This model can be utilized both to inform surgical procedures and provide insight on future cage designs and can be adopted to models without the use of in vivo animal models.
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Affiliation(s)
- Maho Koga
- Meinig School of Biomedical EngineeringCornell UniversityIthacaNew YorkUSA
| | - Byumsu Kim
- Sibley School of Mechanical and Aerospace EngineeringCornell UniversityIthacaNew YorkUSA
| | - Marianne Lintz
- Meinig School of Biomedical EngineeringCornell UniversityIthacaNew YorkUSA
| | | | | | | | | | | | | | | | - Lawrence J. Bonassar
- Meinig School of Biomedical EngineeringCornell UniversityIthacaNew YorkUSA
- Sibley School of Mechanical and Aerospace EngineeringCornell UniversityIthacaNew YorkUSA
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Li KY, Li HL, Chen LJ, Xiang JW, Li CC, Weng JJ, Tian NF. Complications and radiographic changes after implantation of interspinous process devices: average eight-year follow-up. BMC Musculoskelet Disord 2023; 24:667. [PMID: 37612739 PMCID: PMC10463994 DOI: 10.1186/s12891-023-06798-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 08/12/2023] [Indexed: 08/25/2023] Open
Abstract
PURPOSE This study aims to evaluate complications, clinical outcomes, and radiographic results following Coflex implantation. METHODS We retrospectively studied 66 patients who had decompressive surgery combined with Coflex implantation to treat lumbar spinal stenosis. All imaging data were collected and examined for imaging changes. Clinical outcomes, included Oswestry Disability Index (ODI), back and leg visual analog scale (VAS) scores, were evaluated before surgery, six months after surgery and at the last follow-up. The number of complications occurring after five years of follow-up was counted. All reoperation cases were meticulously recorded. RESULTS 66 patients were followed up for 5-14 years. The VAS and ODI scores were significantly improved compared with baseline. Heterotopic Ossification (HO) was detectable in 59 (89.4%). 26 (39.4%) patients had osteolysis at the contact site of Coflex with the spinous process. Coflex loosening was detected in 39 (60%) patients. Spinous process anastomosis was found in 34 (51.5%) patients. There was a statistically significant difference in the VAS score of back pain between patients with and without spinous process anastomosis. Nine cases of lumbar spinal restenosis were observed, and prosthesis fracture was observed in one case. CONCLUSION Our study identified various imaging changes after Coflex implantation, and majority of them did not affect clinical outcomes. The majority of patients had HO, but osteolysis and Coflex loosening were relatively rare. The VAS score for back pain of these patients was higher if they have spinous process anastomosis. After five-year follow-up, we found lumbar spinal restenosis and prosthesis fracture cases.
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Affiliation(s)
- Kai-Yu Li
- Zhejiang Spine Research Center, Department of Spine Surgery, The Second Affiliated Hospital and Yuying, Children's Hospital of Wenzhou Medical University, 109 Xueyuanxi Road, Wenzhou, 325000, Zhejiang, China
| | - Hua-Lin Li
- Zhejiang Spine Research Center, Department of Spine Surgery, The Second Affiliated Hospital and Yuying, Children's Hospital of Wenzhou Medical University, 109 Xueyuanxi Road, Wenzhou, 325000, Zhejiang, China
| | - Lin-Jie Chen
- Zhejiang Spine Research Center, Department of Spine Surgery, The Second Affiliated Hospital and Yuying, Children's Hospital of Wenzhou Medical University, 109 Xueyuanxi Road, Wenzhou, 325000, Zhejiang, China
| | - Jian-Wei Xiang
- Zhejiang Spine Research Center, Department of Spine Surgery, The Second Affiliated Hospital and Yuying, Children's Hospital of Wenzhou Medical University, 109 Xueyuanxi Road, Wenzhou, 325000, Zhejiang, China
| | - Chen-Chao Li
- Zhejiang Spine Research Center, Department of Spine Surgery, The Second Affiliated Hospital and Yuying, Children's Hospital of Wenzhou Medical University, 109 Xueyuanxi Road, Wenzhou, 325000, Zhejiang, China
| | - Jun-Jie Weng
- Zhejiang Spine Research Center, Department of Spine Surgery, The Second Affiliated Hospital and Yuying, Children's Hospital of Wenzhou Medical University, 109 Xueyuanxi Road, Wenzhou, 325000, Zhejiang, China
| | - Nai-Feng Tian
- Zhejiang Spine Research Center, Department of Spine Surgery, The Second Affiliated Hospital and Yuying, Children's Hospital of Wenzhou Medical University, 109 Xueyuanxi Road, Wenzhou, 325000, Zhejiang, China.
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Zhang X, Yang Y, Shen YW, Zhang KR, Ma LT, Ding C, Wang BY, Meng Y, Liu H. Biomechanical performance of the novel assembled uncovertebral joint fusion cage in single-level anterior cervical discectomy and fusion: A finite element analysis. Front Bioeng Biotechnol 2023; 11:931202. [PMID: 36970630 PMCID: PMC10031026 DOI: 10.3389/fbioe.2023.931202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 02/22/2023] [Indexed: 03/11/2023] Open
Abstract
Introduction: Anterior cervical discectomy and fusion (ACDF) is widely accepted as the gold standard surgical procedure for treating cervical radiculopathy and myelopathy. However, there is concern about the low fusion rate in the early period after ACDF surgery using the Zero-P fusion cage. We creatively designed an assembled uncoupled joint fusion device to improve the fusion rate and solve the implantation difficulties. This study aimed to assess the biomechanical performance of the assembled uncovertebral joint fusion cage in single-level ACDF and compare it with the Zero-P device.Methods: A three-dimensional finite element (FE) of a healthy cervical spine (C2−C7) was constructed and validated. In the one-level surgery model, either an assembled uncovertebral joint fusion cage or a zero-profile device was implanted at the C5–C6 segment of the model. A pure moment of 1.0 Nm combined with a follower load of 75 N was imposed at C2 to determine flexion, extension, lateral bending, and axial rotation. The segmental range of motion (ROM), facet contact force (FCF), maximum intradiscal pressure (IDP), and screw−bone stress were determined and compared with those of the zero-profile device.Results: The results showed that the ROMs of the fused levels in both models were nearly zero, while the motions of the unfused segments were unevenly increased. The FCF at adjacent segments in the assembled uncovertebral joint fusion cage group was less than that that of the Zero-P group. The IDP at the adjacent segments and screw–bone stress were slightly higher in the assembled uncovertebral joint fusion cage group than in those of the Zero-P group. Stress on the cage was mainly concentrated on both sides of the wings, reaching 13.4–20.4 Mpa in the assembled uncovertebral joint fusion cage group.Conclusion: The assembled uncovertebral joint fusion cage provided strong immobilization, similar to the Zero-P device. When compared with the Zero-P group, the assembled uncovertebral joint fusion cage achieved similar resultant values regarding FCF, IDP, and screw–bone stress. Moreover, the assembled uncovertebral joint fusion cage effectively achieved early bone formation and fusion, probably due to proper stress distributions in the wings of both sides.
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Nikkhoo M, Chen WC, Lu ML, Fu CJ, Niu CC, Lien HY, Cheng CH. Anatomical parameters alter the biomechanical responses of adjacent segments following lumbar fusion surgery: Personalized poroelastic finite element modelling investigations. Front Bioeng Biotechnol 2023; 11:1110752. [PMID: 36860879 PMCID: PMC9968854 DOI: 10.3389/fbioe.2023.1110752] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/30/2023] [Indexed: 02/17/2023] Open
Abstract
Introduction: While the short-term post-operative outcome of lumbar fusion is satisfying for most patients, adjacent segment disease (ASD) can be prevalent in long-term clinical observations. It might be valuable to investigate if inherent geometrical differences among patients can significantly alter the biomechanics of adjacent levels post-surgery. This study aimed to utilize a validated geometrically personalized poroelastic finite element (FE) modeling technique to evaluate the alteration of biomechanical response in adjacent segments post-fusion. Methods: Thirty patients were categorized for evaluation in this study into two distinct groups [i.e., 1) non-ASD and 2) ASD patients] based on other long-term clinical follow-up investigations. To evaluate the time-dependent responses of the models subjected to cyclic loading, a daily cyclic loading scenario was applied to the FE models. Different rotational movements in different planes were superimposed using a 10 Nm moment after daily loading to compare the rotational motions with those at the beginning of cyclic loading. The biomechanical responses of the lumbosacral FE spine models in both groups were analyzed and compared before and after daily loading. Results: The achieved comparative errors between the FE results and clinical images were on average below 20% and 25% for pre-op and post-op models, respectively, which confirms the applicability of this predictive algorithm for rough pre-planning estimations. The results showed that the disc height loss and fluid loss were increased for the adjacent discs in post-op models after 16 h of cyclic loading. In addition, significant differences in disc height loss and fluid loss were observed between the patients who were in the non-ASD and ASD groups. Similarly, the increased stress and fiber strain in the annulus fibrosus (AF) was higher in the adjacent level of post-op models. However, the calculated stress and fiber strain values were significantly higher for patients with ASD. Discussion: Evaluating the biomechanical response of pre-op and post-op modeling in the non-ASD and ASD groups showed that the inherent geometric differences among patients cause significant variations in the estimated mechanical response. In conclusion, the results of the current study highlighted the effect of geometrical parameters (which may refer to the anatomical conditions or the induced modifications regarding surgical techniques) on time-dependent responses of lumbar spine biomechanics.
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Affiliation(s)
- Mohammad Nikkhoo
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan,Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan,Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Wen-Chien Chen
- Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan,Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Meng-Ling Lu
- Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan,Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Chen-Ju Fu
- Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan,Division of Emergency and Critical Care Radiology, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Chi-Chien Niu
- Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan,Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Hen-Yu Lien
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chih-Hsiu Cheng
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan,Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan,*Correspondence: Chih-Hsiu Cheng,
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Li T, Yan J, Ren Q, Hu J, Wang F, Liu X. Efficacy and Safety of Lumbar Dynamic Stabilization Device Coflex for Lumbar Spinal Stenosis: A Systematic Review and Meta-analysis. World Neurosurg 2023; 170:7-20. [PMID: 36481444 DOI: 10.1016/j.wneu.2022.11.141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022]
Abstract
BACKGROUND This systematic review and meta-analysis were performed to investigate evidence for the comparison of lumbar dynamic stabilization device Coflex (Surgalign, Deerfield, IL) with posterior lumbar fusion for lumbar spinal stenosis). METHODS Relational databases were searched to October 2022. The main outcome measures included operation time, Japanese Orthopedic Association score (JOA), visual analog scale (VAS), Oswestry disability index (ODI), total complications, and adjacent segment degeneration (ASD). Statistical analysis was performed with Review Manager 5.3 (Cochrane Collaboration). RESULTS A total of 26 studies were included. The main results of this meta-analysis showed lumbar dynamic stabilization device Coflex had shorter operation time (mean difference [MD] -50.77 min, 95% CI -57.24 to -44.30, P < 0.00001), less intraoperative blood loss (MD -122.21 mL, 95% CI -129.68 to -94.74, P < 0.00001), and shorter hospital stays (MD -3.21 days, 95% CI -4.04 to -2.37, P < 0.00001). What's more, the JOA score and ODI score were higher in the Coflex group during early follow-up. Yet, there was no significant difference between the 2 groups with the extension of follow-up time. Moreover, the Coflex group had a lower VAS score than fusion treatment (P < 0.00001). Finally, the Coflex group had lower total complications rate (P = 0.03), lower ASD rate (P = 0.001), and higher range of motion (P < 0.00001), but there was no significant difference in reoperation rate and internal fixation problems rate. CONCLUSIONS Current evidence suggests that lumbar dynamic stabilization device Coflex is superior to posterior lumbar fusion in early follow-up. However, considering that the dynamic stabilization device group also has its limitations, these findings need to be further verified by multicenter, double-blind, and large-sample randomized controlled trials.
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Affiliation(s)
- Ting Li
- Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China; Department of Postgraduate, Chengdu Medical College, Chengdu, China
| | - Jingxin Yan
- Department of Interventional Therapy, Affiliated Hospital of Qinghai University, Xining, China
| | - Qiuyu Ren
- Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China; Department of Postgraduate, Chengdu Medical College, Chengdu, China
| | - Jiang Hu
- Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China
| | - Fei Wang
- Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China
| | - Xilin Liu
- Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China.
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Shen YW, Yang Y, Liu H, Qiu Y, Li M, Ma LT, Gan FJ. Biomechanical Evaluation of Intervertebral Fusion Process After Anterior Cervical Discectomy and Fusion: A Finite Element Study. Front Bioeng Biotechnol 2022; 10:842382. [PMID: 35372323 PMCID: PMC8969047 DOI: 10.3389/fbioe.2022.842382] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/15/2022] [Indexed: 12/25/2022] Open
Abstract
Introduction: Anterior cervical discectomy and fusion (ACDF) is a widely accepted surgical procedure in the treatment of cervical radiculopathy and myelopathy. A solid interbody fusion is of critical significance in achieving satisfactory outcomes after ACDF. However, the current radiographic techniques to determine the degree of fusion are inaccurate and radiative. Several animal experiments suggested that the mechanical load on the spinal instrumentation could reflect the fusion process and evaluated the stability of implant. This study aims to investigate the biomechanical changes during the fusion process and explore the feasibility of reflecting the fusion status after ACDF through the load changes borne by the interbody fusion cage. Methods: The computed tomography (CT) scans preoperatively, immediately after surgery, at 3 months, and 6 months follow-up of patients who underwent ACDF at C5/6 were used to construct the C2–C7 finite element (FE) models representing different courses of fusion stages. A 75-N follower load with 1.0-Nm moments was applied to the top of C2 vertebra in the models to simulate flexion, extension, lateral bending, and axial rotation with the C7 vertebra fixed. The Von Mises stress at the surfaces of instrumentation and the adjacent intervertebral disc and force at the facet joints were analyzed. Results: The facet contact force at C5/6 suggested a significantly stepwise reduction as the fusion proceeded while the intradiscal pressure and facet contact force of adjacent levels changed slightly. The stress on the surfaces of titanium plate and screws significantly decreased at 3 and 6 months follow-up. A markedly changed stress distribution in extension among three models was noted in different fusion stages. After solid fusion is achieved, the stress was more uniformly distributed interbody fusion in all loading conditions. Conclusions: Through a follow-up study of 6 months, the stress on the surfaces of cervical instrumentation remarkably decreased in all loading conditions. After solid intervertebral fusion formed, the stress distributions on the surfaces of interbody cage and screws were more uniform. The stress distribution in extension altered significantly in different fusion status. Future studies are needed to develop the interbody fusion device with wireless sensors to achieve longitudinal real-time monitoring of the stress distribution during the course of fusion.
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Affiliation(s)
- Yi-Wei Shen
- Department of Orthopedics, Orthopedic Research Institute, West China Hospital, Sichuan University, Chengdu, China
| | - Yi Yang
- Department of Orthopedics, Orthopedic Research Institute, West China Hospital, Sichuan University, Chengdu, China
| | - Hao Liu
- Department of Orthopedics, Orthopedic Research Institute, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Hao Liu,
| | - Yue Qiu
- West China Biomedical Big Data Center, West China Hospital, Sichuan University, Chengdu, China
| | - Ming Li
- Department of Measurement and Control Technology and Instrument, Sichuan University, Chengdu, China
| | - Li-Tai Ma
- Department of Orthopedics, Orthopedic Research Institute, West China Hospital, Sichuan University, Chengdu, China
| | - Fang-Ji Gan
- Department of Measurement and Control Technology and Instrument, Sichuan University, Chengdu, China
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