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Sønderby AH, Thomsen H, Skals RG, Storm S, Leutscher PDC, Simony A. Thoracic spine X-ray examination of patients with back pain using different breathing technique and exposure times - A diagnostic study. Radiography (Lond) 2024; 30:582-588. [PMID: 38310658 DOI: 10.1016/j.radi.2024.01.011] [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: 08/09/2023] [Revised: 01/04/2024] [Accepted: 01/14/2024] [Indexed: 02/06/2024]
Abstract
INTRODUCTION The breathing and suspended inspiration techniques are often used interchangeably for spine X-ray examinations. However, these techniques are not always adequately supported by clinical evidence. This study aimed to determine the two techniques' diagnostic value and adverse image outcomes. METHODS A total of 400 participants were examined on a Siemens Ysio Max system and randomized into four examination groups: suspended inspiration or breathing techniques with exposure times of 1, 2, and 3.2 s, respectively. Two consultant radiologists conducted the evaluation of the X-ray images. If disagreement was present, the radiologists collaboratively reviewed the X-ray images until a consensus was reached. RESULTS The final 394 study population comprised 275 women and 119 men with a mean age of 64 years (range:18-96 years). The proportions of visually sharp reproduction of the endplates and trabecular structures did not differ significantly with regards to differences in exposure times between groups. The breathing technique groups had significantly higher proportions of blurring and motion artifacts (p < 0.001). However, adverse image outcomes (motions artifacts) were significantly lower in the 1-s exposure group. CONCLUSIONS The suspended inspiration and breathing techniques performed equally well regarding visually sharp reproduction. However, the suspended inspiration technique was superior to the breathing technique. regarding adverse image outcomes, although the latter could be improved by using a shorter exposure time. IMPLICATIONS FOR PRACTICE The suspended inspiration and breathing technique appeared to perform at equal diagnostic levels. The suspended inspiration technique should be preferred due to its reduced risk of adverse image outcomes. However, the risk could also be reduced using a short exposure time with the breathing technique.
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Affiliation(s)
- A H Sønderby
- Department of X-ray Physics North Denmark, Aalborg University Hospital, Merkurvej 13, 9700 Brønderslev, Denmark.
| | - H Thomsen
- Department of Radiology, North Denmark Regional Hospital, Barfredsvej 83, 9900 Frederikshavn, Denmark.
| | - R G Skals
- Unit of Clinical Biostatistics, Sdr. Skovvej 15, 9000 Aalborg, Denmark.
| | - S Storm
- Department of Radiology, Aalborg University Hospital, Hobrovej 18-22, 9100 Aalborg, Denmark.
| | - P D C Leutscher
- Centre for Clinical Research North Denmark Regional Hospital & Department of Clinical Medicine, Aalborg University Hospital, Bispensgade 37, 9800 Hjørrring, Denmark.
| | - A Simony
- Department of Orthopedic Surgery, The Region of Southern Denmark University Hospital, Sygehusvej 24, 6000 Kolding, Denmark.
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Wang K, Wang X, Li Z, Xie T, Wang L, Luo C, Huang S, Zeng J. The Influence of Screw Positioning on Cage Subsidence in Patients with Oblique Lumbar Interbody Fusion Combined with Anterolateral Fixation. Orthop Surg 2023; 15:3263-3271. [PMID: 37771126 PMCID: PMC10694007 DOI: 10.1111/os.13882] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 08/01/2023] [Accepted: 08/04/2023] [Indexed: 09/30/2023] Open
Abstract
OBJECTIVES Cage subsidence (CS) has been reported to be one of the most common complications following oblique lumbar interbody fusion (OLIF). To reduce the incidence of CS and improve intervertebral fusion rates, anterolateral fixation (AF) has been gradually proposed. However, the incidence of CS in patients with oblique lumbar interbody fusion combined with anterolateral fixation (OLIF-AF) is still controversial. Additionally, there is a lack of consensus regarding the optimal placement of screws for OLIF-AF, and the impact of screw placement on the incidence of CS has yet to be thoroughly investigated and validated. The objective of this investigation was to examine the correlation between screw placements and CS and to establish an optimized approach for implantation in OLIF-AF. METHODS A retrospective cohort study was undertaken. From October 2017 to December 2020, a total of 103 patients who received L4/5 OLIF-AF for lumbar spinal stenosis or spondylolisthesis or degenerative instability in our department were followed up for more than 12 months. Demographic and radiographic data of these patients were collected. Additionally, screw placement related parameters, including trajectory and position, were measured by anterior-posterior X-ray and axial CT. Analysis was done by chi-square, independent t-test, univariable and multivariable binary logistic regression to explore the correlation between screw placements and CS. Finally, the receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive ability of screw placement-related parameters. RESULTS A total of 103 patients were included, and CS was found in 28 (27.18%) patients. Univariable analysis was firstly performed for each parameter. Next, variables with p-value of <0.05, including bone mineral density (BMD), concave morphology, and screw placement-related parameters were included in the multivariate logistic regression analysis. Significant predictor factors for subsidence were coronal plane angle (CPA) (OR 0.580 ± 0.208, 95% CI 1.187-2.684), implantation point (IP) (L4) (OR 5.732 ± 2.737, 95% CI 1.445-12.166), and IP (L5) (OR 7.160 ± 3.480, 95% CI 1.405-28.683). Furthermore, ROC curves showed that the predictive accuracy of CS was 88.1% for CPA, 77.6% for IP (L4) and 80.9% for IP (L5). CONCLUSIONS We demonstrate that the trajectory of vertebral screws, including angle and position, was closely related to CS. Inserting screws parallel to each other and as close to the endplate as possible while keeping the cage inside the range of the superior and inferior screws are an optimal implantation strategy for OLIF-AF.
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Affiliation(s)
- Kai Wang
- Department of Orthopaedic Surgery and Orthopaedic Research Institute, West China HospitalSichuan UniversityChengduChina
| | - Xiandi Wang
- Department of Orthopaedic Surgery and Orthopaedic Research Institute, West China HospitalSichuan UniversityChengduChina
| | - Zhuhai Li
- Department of Orthopaedic Surgery and Orthopaedic Research Institute, West China HospitalSichuan UniversityChengduChina
- Department of Spine SurgeryThe People's Hospital of Guangxi Zhuang Autonomous RegionNanningChina
| | - Tianhang Xie
- Department of Orthopaedic Surgery and Orthopaedic Research Institute, West China HospitalSichuan UniversityChengduChina
| | - Lihang Wang
- Department of Orthopaedic Surgery and Orthopaedic Research Institute, West China HospitalSichuan UniversityChengduChina
- Department of Spine SurgeryGuizhou Provincial Orthopedics HospitalGuiyangChina
| | - Chuan Luo
- Department of Orthopaedic Surgery and Orthopaedic Research Institute, West China HospitalSichuan UniversityChengduChina
- School of Mechanical EngineeringSichuan UniversityChengduChina
| | - Shishu Huang
- Department of Orthopaedic Surgery and Orthopaedic Research Institute, West China HospitalSichuan UniversityChengduChina
| | - Jiancheng Zeng
- Department of Orthopaedic Surgery and Orthopaedic Research Institute, West China HospitalSichuan UniversityChengduChina
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Lin M, Doulgeris J, Dhar UK, O’Corner T, Papanastassiou ID, Tsai CT, Vrionis FD. Effect of graded posterior element and ligament removal on annulus stress and segmental stability in lumbar spine stenosis: a finite element analysis study. Front Bioeng Biotechnol 2023; 11:1237702. [PMID: 37790254 PMCID: PMC10543754 DOI: 10.3389/fbioe.2023.1237702] [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: 06/09/2023] [Accepted: 08/30/2023] [Indexed: 10/05/2023] Open
Abstract
The study aimed to investigate the impact of posterior element and ligament removal on the maximum von Mises stress, and maximum shear stress of the eight-layer annulus for treating stenosis at the L3-L4 and L4-L5 levels in the lumbar spine. Previous studies have indicated that laminectomy alone can result in segmental instability unless fusion is performed. However, no direct correlations have been established regarding the impact of posterior and ligament removal. To address this gap, four models were developed: Model 1 represented the intact L2-L5 model, while model 2 involved a unilateral laminotomy involving the removal of a section of the L4 inferior lamina and 50% of the ligament flavum between L4 and L5. Model 3 consisted of a complete laminectomy, which included the removal of the spinous process and lamina of L4, as well as the relevant connecting ligaments between L3-L4 and L4-L5 (ligament flavum, interspinous ligament, supraspinous ligament). In the fourth model, a complete laminectomy with 50% facetectomy was conducted. This involved the same removals as in model 3, along with a 50% removal of the inferior/superior facets of L4 and a 50% removal of the facet capsular ligaments between L3-L4 and L4-L5. The results indicated a significant change in the range of motion (ROM) at the L3-L4 and L4-L5 levels during flexion and torque situations, but no significant change during extension and bending simulation. The ROM increased by 10% from model 1 and 2 to model 3, and by 20% to model 4 during flexion simulation. The maximum shear stress and maximum von-Mises stress of the annulus and nucleus at the L3-L4 levels exhibited the greatest increase during flexion. In all eight layers of the annulus, there was an observed increase in both the maximum shear stress and maximum von-Mises stress from model 1&2 to model 3 and model 4, with the highest rate of increase noted in layers 7&8. These findings suggest that graded posterior element and ligament removal have a notable impact on stress distribution and range of motion in the lumbar spine, particularly during flexion.
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Affiliation(s)
- Maohua Lin
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL, United States
| | - James Doulgeris
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL, United States
| | - Utpal Kanti Dhar
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL, United States
| | - Timothy O’Corner
- Department of Neurosurgery, Marcus Neuroscience Institute, Boca Raton Regional Hospital, Boca Raton, FL, United States
| | | | - Chi-Tay Tsai
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL, United States
| | - Frank D. Vrionis
- Department of Neurosurgery, Marcus Neuroscience Institute, Boca Raton Regional Hospital, Boca Raton, FL, United States
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Cho M, Han JS, Kang S, Ahn CH, Kim DH, Kim CH, Kim KT, Kim AR, Hwang JM. Biomechanical Effects of Different Sitting Postures and Physiologic Movements on the Lumbar Spine: A Finite Element Study. Bioengineering (Basel) 2023; 10:1051. [PMID: 37760153 PMCID: PMC10525568 DOI: 10.3390/bioengineering10091051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/30/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
This study used the finite element method(FEM) to investigate how pressure on the lumbar spine changes during dynamic movements in different postures: standing, erect sitting on a chair, slumped sitting on a chair, and sitting on the floor. Three load modes (flexion, lateral bending, and axial rotation) were applied to the FEM, simulating movements of the lumbar spine. Results showed no significant difference in pressure distribution on the annulus fiber and nucleus pulposus, representing intradiscal pressure, as well as on the cortical bone during movements between standing and erect sitting postures. However, both slumped sitting on a chair and sitting on the floor postures significantly increased pressure on the nucleus pulposus, annulus fibrosus, and cortical bone in all three movements when compared to standing or erect sitting on a chair. Notably, sitting on the floor resulted in even higher pressure on the nucleus pulposus and annulus fibers compared to slumped sitting on a chair. The decreased lumbar lordosis while sitting on the floor led to the highest increase in pressure on the annulus fiber and nucleus pulposus in the lumbar spine. In conclusion, maintaining an erect sitting position with increased lumbar lordosis during seated activities can effectively reduce intradiscal pressure and cortical bone stress associated with degenerative disc diseases and spinal deformities.
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Affiliation(s)
- Mingoo Cho
- Precision Mechanical Process and Control R&D Group, Korea Institute of Industrial Technology, Jinju-si 52845, Republic of Korea; (M.C.); (S.K.)
| | - Jun-Sang Han
- Department of Rehabilitation Medicine, Kyungpook National University Hospital, Daegu 41944, Republic of Korea; (J.-S.H.); (C.-H.A.); (C.-H.K.)
| | - Sungwook Kang
- Precision Mechanical Process and Control R&D Group, Korea Institute of Industrial Technology, Jinju-si 52845, Republic of Korea; (M.C.); (S.K.)
| | - Chang-Hwan Ahn
- Department of Rehabilitation Medicine, Kyungpook National University Hospital, Daegu 41944, Republic of Korea; (J.-S.H.); (C.-H.A.); (C.-H.K.)
| | - Dong-Hee Kim
- Department of Orthopaedic Surgery, Gyeongsang National University, College of Medicine, Jinju-si 52727, Republic of Korea;
| | - Chul-Hyun Kim
- Department of Rehabilitation Medicine, Kyungpook National University Hospital, Daegu 41944, Republic of Korea; (J.-S.H.); (C.-H.A.); (C.-H.K.)
- Department of Rehabilitation Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Kyoung-Tae Kim
- Department of Neurosurgery, Kyungpook National University Hospital, Daegu 41944, Republic of Korea;
- Department of Neurosurgery, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Ae-Ryoung Kim
- Department of Rehabilitation Medicine, Kyungpook National University Hospital, Daegu 41944, Republic of Korea; (J.-S.H.); (C.-H.A.); (C.-H.K.)
- Department of Rehabilitation Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Jong-Moon Hwang
- Department of Rehabilitation Medicine, Kyungpook National University Hospital, Daegu 41944, Republic of Korea; (J.-S.H.); (C.-H.A.); (C.-H.K.)
- Department of Rehabilitation Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
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Zou D, Yue L, Fan Z, Zhao Y, Leng H, Sun Z, Li W. Biomechanical Analysis of Lumbar Interbody Fusion Cages With Various Elastic Moduli in Osteoporotic and Non-osteoporotic Lumbar Spine: A Finite Element Analysis. Global Spine J 2023:21925682231166612. [PMID: 37132375 DOI: 10.1177/21925682231166612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/04/2023] Open
Abstract
STUDY DESIGN Finite element analysis (FEA). OBJECTIVE This study aimed to explore the effects of cage elastic modulus (Cage-E) on the endplate stress in different bone conditions: osteoporosis (OP) and non-osteoporosis (non-OP). We also explored the correlation between endplate thickness and endplate stress. METHOD The FEA models of L4-L5 with lumbar interbody fusion were designed to access the effects of Cage-E on the endplate stress in different bone conditions. Two groups of the Young's moduli of bony structure were assigned to simulate the conditions of OP and non-OP, and the bony endplates were analyzed in 2 kinds of thicknesses: .5 mm and 1.0 mm, with the insertion of cages with different Young's moduli including .5, 1.5, 3, 5, 10, and 20 GPa. After model validation, an axial compressive load of 400 N and a flexion/extension moment of 7.5Nm was performed on the superior surface of L4 vertebral body in order to analyze the distribution of stress. RESULT The maximum Von Mises stress in the endplates increased by up to 100% in the OP model compared with non-OP model under the same condition of cage-E and endplate thickness. In both OP and non-OP models, the maximum endplate stress decreased as the cage-E decreased, but the maximum stress in the lumbar posterior fixation increased as the cage-E decreased. Thinner endplate thickness was associated with increased endplate stress. CONCLUSION The endplate stress is higher in osteoporotic bone than non-osteoporotic bone, which explains part of the mechanism of OP-related cage subsidence. It is reasonable to reduce the endplate stress by reducing the cage-E, but we should balance the risk of fixation failure. Endplate thickness is also important when evaluating the cage subsidence risk.
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Affiliation(s)
- Da Zou
- Orthopaedics Department, Peking University Third Hospital, China
- Ministry of Education, Engineering Research Center of Bone and Joint Precision Medicine, China
- Orthopaedics Department, Beijing Key Laboratory of Spinal Disease Research, China
| | - Lihao Yue
- Orthopaedics Department, Peking University Health Science Center, China
| | - Zheyu Fan
- Orthopaedics Department, Peking University Health Science Center, China
| | - Yi Zhao
- Orthopaedics Department, Peking University Health Science Center, China
| | - Huijie Leng
- Orthopaedics Department, Peking University Third Hospital, China
- Ministry of Education, Engineering Research Center of Bone and Joint Precision Medicine, China
- Orthopaedics Department, Beijing Key Laboratory of Spinal Disease Research, China
| | - Zhuoran Sun
- Orthopaedics Department, Peking University Third Hospital, China
- Ministry of Education, Engineering Research Center of Bone and Joint Precision Medicine, China
- Orthopaedics Department, Beijing Key Laboratory of Spinal Disease Research, China
| | - Weishi Li
- Orthopaedics Department, Peking University Third Hospital, China
- Ministry of Education, Engineering Research Center of Bone and Joint Precision Medicine, China
- Orthopaedics Department, Beijing Key Laboratory of Spinal Disease Research, China
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Li Y, Yao Q, Yu H, Xie X, Shi Z, Li S, Qiu H, Li C, Qin J. Automated segmentation of vertebral cortex with 3D U-Net-based deep convolutional neural network. Front Bioeng Biotechnol 2022; 10:996723. [PMCID: PMC9626964 DOI: 10.3389/fbioe.2022.996723] [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: 07/18/2022] [Accepted: 09/02/2022] [Indexed: 11/13/2022] Open
Abstract
Objectives: We developed a 3D U-Net-based deep convolutional neural network for the automatic segmentation of the vertebral cortex. The purpose of this study was to evaluate the accuracy of the 3D U-Net deep learning model. Methods: In this study, a fully automated vertebral cortical segmentation method with 3D U-Net was developed, and ten-fold cross-validation was employed. Through data augmentation, we obtained 1,672 3D images of chest CT scans. Segmentation was performed using a conventional image processing method and manually corrected by a senior radiologist to create the gold standard. To compare the segmentation performance, 3D U-Net, Res U-Net, Ki U-Net, and Seg Net were used to segment the vertebral cortex in CT images. The segmentation performance of 3D U-Net and the other three deep learning algorithms was evaluated using DSC, mIoU, MPA, and FPS. Results: The DSC, mIoU, and MPA of 3D U-Net are better than the other three strategies, reaching 0.71 ± 0.03, 0.74 ± 0.08, and 0.83 ± 0.02, respectively, indicating promising automated segmentation results. The FPS is slightly lower than that of Seg Net (23.09 ± 1.26 vs. 30.42 ± 3.57). Conclusion: Cortical bone can be effectively segmented based on 3D U-net.
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Affiliation(s)
- Yang Li
- Department of Radiology, The Second Affiliated Hospital of Shandong First Medical University, Tai’an, China
| | - Qianqian Yao
- Department of Radiology, The Second Affiliated Hospital of Shandong First Medical University, Tai’an, China
| | - Haitao Yu
- Mechanical and Electrical Engineering College, Hainan University, Haikou, China
| | - Xiaofeng Xie
- Mechanical and Electrical Engineering College, Hainan University, Haikou, China
| | - Zeren Shi
- Hangzhou Shimai Intelligent Technology Co., Ltd., Hangzhou, China
| | - Shanshan Li
- Department of Radiology, The Second Affiliated Hospital of Shandong First Medical University, Tai’an, China
| | - Hui Qiu
- Department of Radiology, The Second Affiliated Hospital of Shandong First Medical University, Tai’an, China
| | - Changqin Li
- Department of Radiology, The Second Affiliated Hospital of Shandong First Medical University, Tai’an, China
| | - Jian Qin
- Department of Radiology, The Second Affiliated Hospital of Shandong First Medical University, Tai’an, China,*Correspondence: Jian Qin,
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Optimization of Spinal Reconstructions for Thoracolumbar Burst Fractures to Prevent Proximal Junctional Complications: A Finite Element Study. Bioengineering (Basel) 2022; 9:bioengineering9100491. [DOI: 10.3390/bioengineering9100491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/17/2022] [Accepted: 09/19/2022] [Indexed: 11/16/2022] Open
Abstract
The management strategies of thoracolumbar (TL) burst fractures include posterior, anterior, and combined approaches. However, the rigid constructs pose a risk of proximal junctional failure. In this study, we aim to systemically evaluate the biomechanical performance of different TL reconstruction constructs using finite element analysis. Furthermore, we investigate the motion and the stress on the proximal junctional level adjacent to the constructs. We used a T10-L3 finite element model and simulated L1 burst fracture. Reconstruction with posterior instrumentation (PI) alone (U2L2 and U1L1+(intermediate screw) and three-column spinal reconstruction (TCSR) constructs (U1L1+PMMA and U1L1+Cage) were compared. Long-segment PI resulted in greater global motion reduction compared to constructs with short-segment PI. TCSR constructs provided better stabilization in L1 compared to PI alone. Decreased intradiscal and intravertebral pressure in the proximal level were observed in U1L1+IS, U1L1+PMMA, and U1L1+Cage compared to U2L2. The stress and strain energy of the pedicle screws decreased when anterior reconstruction was performed in addition to PI. We showed that TCSR with anterior reconstruction and SSPI provided sufficient immobilization while offering additional advantages in the preservation of physiological motion, the decreased burden on the proximal junctional level, and lower risk of implant failure.
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Yeni YN, Dix MR, Xiao A, Oravec DJ, Flynn MJ. Measuring the thickness of vertebral endplate and shell using digital tomosynthesis. Bone 2022; 157:116341. [PMID: 35092890 PMCID: PMC8858866 DOI: 10.1016/j.bone.2022.116341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 12/07/2021] [Accepted: 01/23/2022] [Indexed: 02/05/2023]
Abstract
The vertebral endplate and cortical shell play an important structural role and contribute to the overall strength of the vertebral body, are at highest risk of initial failure, and are involved in degenerative disease of the spine. The ability to accurately measure the thickness of these structures is therefore important, even if difficult due to relatively low resolution clinical imaging. We posit that digital tomosynthesis (DTS) may be a suitable imaging modality for measurement of endplate and cortical shell thickness owing to the ability to reconstruct multiplanar images with good spatial resolution at low radiation dose. In this study, for 25 cadaveric L1 vertebrae, average and standard deviation of endplate and cortical shell thickness were measured using images from DTS and microcomputed tomography (μCT). For endplate thickness measurements, significant correlations between DTS and μCT were found for all variables when comparing thicknesses measured in both the overall endplate volume (R2 = 0.25-0.54) and when measurements were limited to a central range of coronal or sagittal slices (R2 = 0.24-0.62). When compared to reference values from the overall shell volume, DTS thickness measurements were generally nonsignificant. However, when measurement of cortical shell thickness was limited to a range of central slices, DTS outcomes were significantly correlated with reference values for both sagittal and coronal central regions (R2 = 0.21-0.49). DTS may therefore offer a means for measurement of endplate thickness and, within a limited sagittal or coronal measurement volume, for measurement of cortical shell thickness.
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Affiliation(s)
- Yener N Yeni
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States of America.
| | - Michael R Dix
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States of America; School of Medicine, Wayne State University, Detroit, MI, United States of America
| | - Angela Xiao
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States of America
| | - Daniel J Oravec
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States of America
| | - Michael J Flynn
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI, United States of America
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Wong CE, Hu HT, Tsai CH, Li JL, Hsieh CC, Huang KY. Comparison of Posterior Fixation Strategies for Thoracolumbar Burst Fracture: A Finite Element Study. J Biomech Eng 2021; 143:1104431. [PMID: 33729440 DOI: 10.1115/1.4050537] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Indexed: 11/08/2022]
Abstract
The management of thoracolumbar (TL) burst fractures remained challenging. Due to the complex nature of the fractured vertebrae and the lack of clinical and biomechanical evidence, currently, there was still no guideline to select the optimal posterior fixation strategy for TL burst fracture. We utilized a T10-L3 TL finite element model to simulate L1 burst fracture and four surgical constructs with one- or two-level suprajacent and infrajacent instrumentation (U1L1, U1L2, U2L1, and U2L2). This study was aimed to compare the biomechanical properties and find an optimal fixation strategy for TL burst fracture in order to minimize motion in the fractured level without exerting significant burden in the construct. Our result showed that two-level infrajacent fixation (U1L2 and U2L2) resulted in greater global motion reduction ranging from 66.0 to 87.3% compared to 32.0 to 47.3% in one-level infrajacent fixation (U1L1 and U2L1). Flexion produced the largest pathological motion in the fractured level but the differences between the constructs were small, all within 0.26 deg. Comparisons in implant stress showed that U2L1 and U2L2 had an average 25.3 and 24.8% less von Mises stress in the pedicle screws compared to U1L1 and U1L2, respectively. The construct of U2L1 had better preservation of the physiological spinal motion while providing sufficient range of motion reduction at the fractured level. We suggested that U2L1 is a good alternative to the standard long-segment fixation with better preservation of physiological motion and without an increased risk of implant failure.
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Affiliation(s)
- Chia-En Wong
- Section of Neurosurgery, Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
| | - Hsuan-Teh Hu
- Department of Civil Engineering, National Cheng Kung University, Tainan 701, Taiwan; Department of Civil and Disaster Prevention Engineering, National United University, Miaoli 360, Taiwan
| | - Cho-Hsuan Tsai
- Department of Civil Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | - Jun-Liang Li
- Department of Otolaryngology, Tungs' Taichung MetroHarbor Hospital, Taichung 433, Taiwan
| | - Chin-Chiang Hsieh
- Department of Radiology, Tainan Hospital, Ministry of Health and Welfare, Tainan 700, Taiwan
| | - Kuo-Yuan Huang
- Department of Orthopedics,National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
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Wojtków M, Głowacki M, Pezowicz C. Multiscale structural characterization of the vertebral endplate in animal models. J Anat 2021; 239:70-80. [PMID: 33521970 DOI: 10.1111/joa.13402] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/05/2021] [Accepted: 01/12/2021] [Indexed: 01/01/2023] Open
Abstract
Research in the field of spinal biomechanics, including analyses of the impact of implants on the stability of the spine, is conducted extensively in animal models. One of the basic problems in spinal implantation is the transfer and distribution of loads carried by the spine on the surfaces of the vertebral bodies. An important factor in proper cooperation of spinal implants with the vertebrae is the endplate (EP), which is why the EP in the animal model used for testing should be as similar as possible to the human EP. Therefore, this study involved multiscale structural and morphometric analyses of the animal models most commonly used in spinal biomechanics research, i.e. pig, ovine, and bovine tail. The tests were performed on 28 lumbar porcine, ovine, and bovine vertebrae. Both cranial and caudal EPs were analysed in three selected areas: anterior, middle, and posterior EPs. The conducted tests included a morphometric analysis of the trabecular bone (TB) layer of the EP as well as microscopic analysis at the mesoscale (total thickness) and microscale (thickness of the individual EP layers). The porcine EP had a characteristic increased circumferential thickness (~3 mm) with a significant narrowing in the central region (50%-60%). The convex cranial ovine EP had a constant thickness throughout the cross-section and the concave caudal EP showed ~35% narrowing in the central region. The thickest EPs were observed in the bovine tail model with negligibly small narrowing in the central region (~5%). The thickness of the cartilaginous layer in the porcine and bovine models reached up to 1 mm in the peripheral regions and decreased in the central part. The growth plate layer had a similar thickness in all the models. On the other hand, the narrowing of the total thickness of the EPs in the central region was mainly due to a decrease in the VEP thickness. In the ovine and bovine models, the central region of the EP was characterized by large isotropy and trabeculae of mixed or rod-like shape. By contrast, in the pig, this region had plate-like trabeculae of anisotropic nature. The porcine model was identified as best reflecting the shape and structure of the human EP and as the best surrogate model for the human EP model. This choice is particularly important in the context of biomechanical research.
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Affiliation(s)
- Magdalena Wojtków
- Department of Mechnics, Materials and Biomedical Engineering, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - Maciej Głowacki
- Department of Paediatric Orthopaedics and Traumatology, Poznan University of Medical Sciences, Poznan, Poland
| | - Celina Pezowicz
- Department of Mechnics, Materials and Biomedical Engineering, Wroclaw University of Science and Technology, Wroclaw, Poland
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Auger JD, Frings N, Wu Y, Marty AG, Morgan EF. Trabecular Architecture and Mechanical Heterogeneity Effects on Vertebral Body Strength. Curr Osteoporos Rep 2020; 18:716-726. [PMID: 33215364 PMCID: PMC7891914 DOI: 10.1007/s11914-020-00640-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/24/2020] [Indexed: 12/29/2022]
Abstract
PURPOSE OF REVIEW We aimed to synthesize the recent work on the intra-vertebral heterogeneity in density, trabecular architecture and mechanical properties, its implications for fracture risk, its association with degeneration of the intervertebral discs, and its implications for implant design. RECENT FINDINGS As compared to the peripheral regions of the centrum, the central region of the vertebral body exhibits lower density and more sparse microstructure. As compared to the anterior region, the posterior region shows higher density. These variations are more pronounced in vertebrae from older persons and in those adjacent to degenerated discs. Mixed results have been reported in regard to variation along the superior-inferior axis and to relationships between the heterogeneity in density and vertebral strength and fracture risk. These discrepancies highlight that, first, despite the large amount of study of the intra-vertebral heterogeneity in microstructure, direct study of that in mechanical properties has lagged, and second, more measurements of vertebral loading are needed to understand how the heterogeneity affects distributions of stress and strain in the vertebra. These future areas of study are relevant not only to the question of spine fractures but also to the design and selection of implants for spine fusion and disc replacement. The intra-vertebral heterogeneity in microstructure and mechanical properties may be a product of mechanical adaptation as well as a key determinant of the ability of the vertebral body to withstand a given type of loading.
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Affiliation(s)
- Joshua D Auger
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA
| | - Neilesh Frings
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Yuanqiao Wu
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA
| | - Andre Gutierrez Marty
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA
| | - Elise F Morgan
- Department of Mechanical Engineering, Boston University, 110 Cummington Mall, Boston, MA, 02215, USA.
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA.
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