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Liu F, Feng X, Deng G, Leung F, Wang C, Chen B. Biomechanical comparison of a new undercut thread design vs. the V-shape thread design for pedicle screws. Spine J 2024:S1529-9430(24)00263-8. [PMID: 38843954 DOI: 10.1016/j.spinee.2024.05.006] [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] [Received: 01/19/2024] [Revised: 04/19/2024] [Accepted: 05/20/2024] [Indexed: 07/01/2024]
Abstract
BACKGROUND CONTEXT Thread shape is regarded as an important factor influencing the fixation strength and osseointegration of bone screws. However, commercial pedicle screws with a V-shaped thread are prone to generating stress concentration at the bone-screw interface, thereby increasing the risk of screw loosening. Thus, modification of the pedicle-screw thread is imperative. PURPOSE This study aimed to investigate the fixation stability of pedicle screws with the new undercut thread design in comparison to pedicle screws with a V-shaped thread. STUDY DESIGN In vitro cadaveric biomechanical test and finite element analysis (FEA). METHODS Pedicle screws with the undercut thread (characterized by a flat crest feature and a tip-facing undercut feature) were custom-manufactured, whereas those with the V-shaped thread were procured from a commercial supplier. Fixation stability was assessed by the cyclic nonpullout compressive biomechanical testing on cadaveric female osteoporotic vertebrae. The vertical displacement and rotation angle of the 2 types of pedicle screws were calculated every 100 cycles to evaluate their resistance to migration and rotation. FEA was conducted to investigate the stress distribution and bone damage at the bone-screw interface for both types of pedicle screws. RESULTS Biomechanical testing revealed that the pedicle screws with the undercut thread exhibited significantly lower vertical displacement and rotation angles than the pedicle screws with the V-shape thread (P < 0.05). FEA results demonstrated a more uniform stress distribution in the bone surrounding the thread in the undercut design than in the V-shape design. Additionally, bone damage resulting from the pedicle screw was lower in the undercut design than in the V-shape design. CONCLUSIONS Pedicle screws with an undercut thread are less prone to migration and rotation and thus more stable in the bone than those with a V-shape thread. CLINICAL SIGNIFICANCE The undercut thread design may reduce the incidence of pedicle-screw loosening.
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Affiliation(s)
- Fei Liu
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaoreng Feng
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China; Department of Orthopaedics and Traumatology, Yangjiang People's Hospital, Yangjiang, China
| | - Geyang Deng
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Frankie Leung
- Department of Orthopaedics and Traumatology, Queen Mary Hospital, the University of Hong Kong, Hong Kong SAR, China
| | - Chengyong Wang
- Guangdong Provincial Key Laboratory of Minimally Invasive Surgical Instruments and Manufacturing Technology, Guangdong University of Technology, Guangzhou, China
| | - Bin Chen
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China.
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Liu G, Huang W, Leng N, He P, Li X, Lin M, Lian Z, Wang Y, Chen J, Cai W. Comparative Biomechanical Stability of the Fixation of Different Miniplates in Restorative Laminoplasty after Laminectomy: A Finite Element Study. Bioengineering (Basel) 2024; 11:519. [PMID: 38790385 PMCID: PMC11117612 DOI: 10.3390/bioengineering11050519] [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: 04/04/2024] [Revised: 05/08/2024] [Accepted: 05/17/2024] [Indexed: 05/26/2024] Open
Abstract
A novel H-shaped miniplate (HSM) was specifically designed for restorative laminoplasties to restore patients' posterior elements after laminectomies. A validated finite element (FE) model of L2/4 was utilized to create a laminectomy model, as well as three restorative laminoplasty models based on the fixation of different miniplates after a laminectomy (the RL-HSM model, the RL-LSM model, and the RL-THM model). The biomechanical effects of motion and displacement on a laminectomy and restorative laminoplasty with three different shapes for the fixation of miniplates were compared under the same mechanical conditions. This study aimed to validate the biomechanical stability, efficacy, and feasibility of a restorative laminoplasty with the fixation of miniplates post laminectomy. The laminectomy model demonstrated the greatest increase in motion and displacement, especially in axial rotation, followed by extension, flexion, and lateral bending. The restorative laminoplasty was exceptional in preserving the motion and displacement of surgical segments when compared to the intact state. This preservation was particularly evident in lateral bending and flexion/extension, with a slight maintenance efficacy observed in axial rotation. Compared to the laminectomy model, the restorative laminoplasties with the investigated miniplates demonstrated a motion-limiting effect for all directions and resulted in excellent stability levels under axial rotation and flexion/extension. The greatest reduction in motion and displacement was observed in the RL-HSM model, followed by the RL-LSM model and then the RL-THM model. When comparing the fixation of different miniplates in restorative laminoplasties, the HSMs were found to be superior to the LSMs and THMs in maintaining postoperative stability, particularly in axial rotation. The evidence suggests that a restorative laminoplasty with the fixation of miniplates is more effective than a conventional laminectomy due to the biomechanical effects of restoring posterior elements, which helps patients regain motion and limit load displacement responses in the spine after surgery, especially in axial rotation and flexion/extension. Additionally, our evaluation in this research study could benefit from further research and provide a methodological and modeling basis for the design and optimization of restorative laminoplasties.
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Affiliation(s)
- Guoyin Liu
- Department of Orthopedics, The Affiliated Jinling Hospital of Nanjing Medical University, Nanjing 211166, China; (G.L.); (W.H.); (N.L.); (P.H.); (M.L.)
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Weiqian Huang
- Department of Orthopedics, The Affiliated Jinling Hospital of Nanjing Medical University, Nanjing 211166, China; (G.L.); (W.H.); (N.L.); (P.H.); (M.L.)
| | - Nannan Leng
- Department of Orthopedics, The Affiliated Jinling Hospital of Nanjing Medical University, Nanjing 211166, China; (G.L.); (W.H.); (N.L.); (P.H.); (M.L.)
| | - Peng He
- Department of Orthopedics, The Affiliated Jinling Hospital of Nanjing Medical University, Nanjing 211166, China; (G.L.); (W.H.); (N.L.); (P.H.); (M.L.)
| | - Xin Li
- Department of Orthopedics, Central Military Commission Joint Logistics Support Force 904th Hospital, Wuxi 214044, China;
| | - Muliang Lin
- Department of Orthopedics, The Affiliated Jinling Hospital of Nanjing Medical University, Nanjing 211166, China; (G.L.); (W.H.); (N.L.); (P.H.); (M.L.)
| | - Zhonghua Lian
- Xiamen Medical Device Research and Testing Center, Xiamen 361022, China;
| | - Yong Wang
- Outpatient Department of The Affiliated Jinling Hospital of Nanjing Medical University, Nanjing 211166, China;
| | - Jianmin Chen
- Department of Orthopedics, The Affiliated Jinling Hospital of Nanjing Medical University, Nanjing 211166, China; (G.L.); (W.H.); (N.L.); (P.H.); (M.L.)
| | - Weihua Cai
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
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Huang Y, Maimaiti A, Tian Y, Li Z, Kahaer A, Rexiti P. Biomechanical investigation of the hybrid lumbar fixation technique with traditional and cortical bone trajectories in transforaminal lumbar interbody fusion: finite element analysis. J Orthop Surg Res 2023; 18:549. [PMID: 37525283 PMCID: PMC10388474 DOI: 10.1186/s13018-023-04027-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 07/17/2023] [Indexed: 08/02/2023] Open
Abstract
OBJECTIVE To compare the biomechanical performance of the hybrid lumbar fixation technique with the traditional and cortical bone trajectory techniques using the finite element method. METHODS Four adult wet lumbar spine specimens were provided by the Department of Anatomy and Research of Xinjiang Medical University, and four L1-S1 lumbar spine with transforaminal lumbar interbody fusion (TLIF) models at L4-L5 segment and four different fixation techniques were established: bilateral traditional trajectory screw fixation (TT-TT), bilateral cortical bone trajectory screw fixation (CBT-CBT), hybrid CBT-TT (CBT screws at L4 and TT screws at L5) and TT-CBT (TT screws at L4 and CBT screws at L5). The range of motion (ROM) of the L4-L5 segment, von Mises stress of cage, internal fixation, and rod were compared in flexion, extension, left and right bending, and left and right rotation. RESULTS Compared with the TT-TT group, the TT-CBT group exhibited lower ROM of L4-L5 segment, especially in left-sided bending; the CBT-TT group had the lowest ROM of L4-L5 segment in flexion and extension among the four fixation methods. Compared with the CBT-CBT group, the peak cage stress in the TT-CBT group was reduced by 9.9%, 18.1%, 21.5%, 23.3%, and 26.1% in flexion, left bending, right bending, left rotation, and right rotation conditions, respectively, but not statistically significant (P > 0.05). The peak stress of the internal fixation system in the TT-CBT group was significantly lower than the other three fixation methods in all five conditions except for extension, with a statistically significant difference between the CBT-TT and TT-CBT groups in the left rotation condition (P = 0.017). In addition, compared with the CBT-CBT group, the peak stress of the rod in the CBT-TT group decreased by 34.8%, 32.1%, 28.2%, 29.3%, and 43.0% under the six working conditions of flexion, extension, left bending, left rotation, and right rotation, respectively, but not statistically significant (P > 0.05). CONCLUSIONS Compared with the TT-TT and CBT-CBT fixation methods in TLIF, the hybrid lumbar fixation CBT-TT and TT-CBT techniques increase the biomechanical stability of the internal fixation structure of the lumbar fusion segment to a certain extent and provide a corresponding theoretical basis for further development in the clinic.
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Affiliation(s)
- Ying Huang
- Xinjiang Medical University, Urumqi, China
| | - Abulikemu Maimaiti
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | | | | | - Alafate Kahaer
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Paerhati Rexiti
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China.
- Key Laboratory of High Incidence Disease Research in Xingjiang (Xinjiang Medical University), Ministry of Education, Urumqi, China.
- Xinjiang Clinical Research Center for Orthopedics, Urumqi, China.
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Zhang R, Kahaer A, Niu H, Wang J, Jumahan A, Qiu Y, Guo H, Rexiti P. Biomechanical evaluation of the hybrid pedicle screw-cortical bone trajectory technique in transforaminal lumbar interbody fusion to adjacent segment degeneration-finite element analysis. BMC Musculoskelet Disord 2023; 24:409. [PMID: 37221546 DOI: 10.1186/s12891-023-06411-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 04/07/2023] [Indexed: 05/25/2023] Open
Abstract
BACKGROUND Transforaminal lumbar interbody fusion is an effective surgical treatment of intervertebral disk herniation. However, its clinical efficacy for adjacent segment disk degeneration (ASDD) after hybrid bilateral pedicle screw - bilateral cortical screw (pedicle screw at L4 and cortical bone trajectory screw at L5) and hybrid bilateral cortical screw - bilateral pedicle screw (bilateral cortical screw at L4 and bilateral pedicle screw at L5) remains undiscovered. Therefore, the aim of this study is to evaluate the effect of the hybrid bilateral pedicle screw - bilateral cortical screw and hybrid bilateral cortical screw - bilateral pedicle screw on the adjacent segment via a 3-dimensional (3D) finite element (FE) analysis. METHODS Four human cadaveric lumbar spine specimens were provided by the anatomy teaching and research department of Xinjiang Medical University. Four finite element models of L1-S1 lumbar spine segment were generated. For each of these, four lumbar transforaminal lumbar interbody fusion models at L4-L5 segment with the following instruments were created: hybrid bilateral pedicle screw - bilateral cortical screw, bilateral cortical screw - bilateral cortical screw (bilateral cortical screw at both L4 and L5 segments), bilateral pedicle screw - bilateral pedicle screw (bilateral pedicle screw at both L4 and L5 segments), and hybrid bilateral cortical screw - bilateral pedicle screw. A 400-N compressive load with 7.5 Nm moments was applied for the simulation of flexion, extension, lateral bending, and rotation. The range of motion of L3-L4 and L5-S1 segments and von Mises stress of the intervertebral disc at the adjacent segment were compared. RESULTS Hybrid bilateral pedicle screw - bilateral cortical screw has the lowest range of motion at L3-L4 segment in flexion, extension, and lateral bending, and the highest disc stress in all motions, while the range of motion at L5-S1 segment and disc stress was lower than bilateral pedicle screw - bilateral pedicle screw in flexion, extension, and lateral bending, and higher than bilateral cortical screw - bilateral cortical screw in all motions. The range of motion of hybrid bilateral cortical screw - bilateral pedicle screw at L3-L4 segment was lower than bilateral pedicle screw - bilateral pedicle screw and higher than bilateral cortical screw - bilateral cortical screw in flexion, extension, and lateral bending, and the range of motion at L5-S1 segment was higher than bilateral pedicle screw - bilateral pedicle screw in flexion, lateral bending, and axial rotation. The disc stress at L3-L4 segment was lowest and more dispersed in all motions, and the disc stress at L5-S1 segment was higher than bilateral pedicle screw - bilateral pedicle screw in lateral bending and axial rotation, but more dispersed. CONCLUSION Hybrid bilateral cortical screw - bilateral pedicle screw decreases the impact on adjacent segments after spinal fusion, reduces the iatrogenic injury to the paravertebral tissues, and provides throughout decompression of the lateral recess.
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Affiliation(s)
- Rui Zhang
- Second Clinical Medical College, Xinjiang Medical University, Urumqi, China
| | - Alafate Kahaer
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan South Road, Urumqi, China
| | - Hanqian Niu
- Fifth Clinical Medical College, Xinjiang Medical University, Urumqi, China
| | - Jingwen Wang
- Second Clinical Medical College, Xinjiang Medical University, Urumqi, China
| | - Ayididaer Jumahan
- First Clinical Medical College, Xinjiang Medical University, Urumqi, China
| | - Yanning Qiu
- First Clinical Medical College, Xinjiang Medical University, Urumqi, China
| | - Hailong Guo
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan South Road, Urumqi, China.
| | - Paerhati Rexiti
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan South Road, Urumqi, China.
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Pei B, Xu Y, Zhao Y, Wu X, Lu D, Wang H, Wu S. Biomechanical comparative analysis of conventional pedicle screws and cortical bone trajectory fixation in the lumbar spine: An in vitro and finite element study. Front Bioeng Biotechnol 2023; 11:1060059. [PMID: 36741751 PMCID: PMC9892841 DOI: 10.3389/fbioe.2023.1060059] [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: 10/04/2022] [Accepted: 01/09/2023] [Indexed: 01/21/2023] Open
Abstract
Numerous screw fixation systems have evolved in clinical practice as a result of advances in screw insertion technology. Currently, pedicle screw (PS) fixation technology is recognized as the gold standard of posterior lumbar fusion, but it can also have some negative complications, such as screw loosening, pullout, and breakage. To address these concerns, cortical bone trajectory (CBT) has been proposed and gradually developed. However, it is still unclear whether cortical bone trajectory can achieve similar mechanical stability to pedicle screw and whether the combination of pedicle screw + cortical bone trajectory fixation can provide a suitable mechanical environment in the intervertebral space. The present study aimed to investigate the biomechanical responses of the lumbar spine with pedicle screw and cortical bone trajectory fixation. Accordingly, finite element analysis (FEA) and in vitro specimen biomechanical experiment (IVE) were performed to analyze the stiffness, range of motion (ROM), and stress distribution of the lumbar spine with various combinations of pedicle screw and cortical bone trajectory screws under single-segment and dual-segment fixation. The results show that dual-segment fixation and hybrid screw placement can provide greater stiffness, which is beneficial for maintaining the biomechanical stability of the spine. Meanwhile, each segment's range of motion is reduced after fusion, and the loss of adjacent segments' range of motion is more obvious with longer fusion segments, thereby leading to adjacent-segment disease (ASD). Long-segment internal fixation can equalize total spinal stresses. Additionally, cortical bone trajectory screws perform better in terms of the rotation resistance of fusion segments, while pedicle screw screws perform better in terms of flexion-extension resistance, as well as lateral bending. Moreover, the maximum screw stress of L4 cortical bone trajectory/L5 pedicle screw is the highest, followed by L45 cortical bone trajectory. This biomechanical analysis can accordingly provide inspiration for the choice of intervertebral fusion strategy.
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Affiliation(s)
- Baoqing Pei
- Beijing key laboratory for design and evaluation technology of advanced implantable & interventional medical devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Yangyang Xu
- Beijing key laboratory for design and evaluation technology of advanced implantable & interventional medical devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Yafei Zhao
- Aerospace center hospital, Beijing, China
| | - Xueqing Wu
- Beijing key laboratory for design and evaluation technology of advanced implantable & interventional medical devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China,*Correspondence: Xueqing Wu, ; Shuqin Wu,
| | - Da Lu
- Beijing key laboratory for design and evaluation technology of advanced implantable & interventional medical devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Haiyan Wang
- School of Basic Medicine, Inner Mongolia Medical University, Hohhot, China
| | - Shuqin Wu
- School of Big Data and Information, Shanxi College of Technology, Shanxi, China,*Correspondence: Xueqing Wu, ; Shuqin Wu,
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Peng SB, Yuan XC, Lu WZ, Yu KX. Application of the cortical bone trajectory technique in posterior lumbar fixation. World J Clin Cases 2023; 11:255-267. [PMID: 36686364 PMCID: PMC9850973 DOI: 10.12998/wjcc.v11.i2.255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/29/2022] [Accepted: 01/05/2023] [Indexed: 01/12/2023] Open
Abstract
The cortical bone trajectory (CBT) is a novel technique in lumbar fixation and fusion. The unique caudocephalad and medial-lateral screw trajectories endow it with excellent screw purchase for vertebral fixation via a minimally invasive method. The combined use of CBT screws with transforaminal or posterior lumbar interbody fusion can treat a variety of lumbar diseases, including spondylolisthesis or stenosis, and can also be used as a remedy for revision surgery when the pedicle screw fails. CBT has obvious advantages in terms of surgical trauma, postoperative recovery, prevention and treatment of adjacent vertebral disease, and the surgical treatment of obese and osteoporosis patients. However, the concept of CBT internal fixation technology appeared relatively recently; consequently, there are few relevant clinical studies, and the long-term clinical efficacy and related complications have not been reported. Therefore, large sample and prospective studies are needed to further reveal the long-term complications and fusion rate. As a supplement to the traditional pedicle trajectory fixation technique, the CBT technique is a good choice for the treatment of lumbar diseases with accurate screw placement and strict indications and is thus deserving of clinical recommendation.
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Affiliation(s)
- Shi-Bo Peng
- Department of Orthopedics, Chongqing Nanchuan Hospital of Traditional Chinese Medicine, Chongqing 408400, China
| | - Xi-Chuan Yuan
- Department of Orthopedics, Chongqing Nanchuan Hospital of Traditional Chinese Medicine, Chongqing 408400, China
| | - Wei-Zhong Lu
- Department of Orthopedics, Chongqing Hospital of Traditional Chinese Medicine, Chongqing 400021, China
| | - Ke-Xiao Yu
- Department of Orthopedics, Chongqing Hospital of Traditional Chinese Medicine, Chongqing 400021, China
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Ji Y, Zhang Q, Song Y, Hu Q, Fekete G, Baker JS, Gu Y. Biomechanical characteristics of 2 different posterior fixation methods of bilateral pedicle screws: A finite element analysis. Medicine (Baltimore) 2022; 101:e30419. [PMID: 36086784 PMCID: PMC10980486 DOI: 10.1097/md.0000000000030419] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 07/27/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND To explore the biomechanical characteristics of 2 posterior bilateral pedicle screw fixation methods using finite element analysis. METHODS A normal L3-5 finite element model was established. Based on the verification of its effectiveness, 2 different posterior internal fixation methods were simulated: bilateral pedicle screws (model A) were placed in the L3 and L5 vertebral bodies, and bilateral pedicle screws (model B) were placed in the L3, L4, and L5 vertebral bodies. The stability and stress differences of intervertebral discs, endplates, screws, and rods between models were compared. RESULTS Compared with the normal model, the maximum stress of the range of motion, intervertebral disc, and endplate of the 2 models decreased significantly. Under the 6 working conditions, the 2 internal fixation methods have similar effects on the stress of the endplate and intervertebral disc, but the maximum stress of the screws and rods of model B is smaller than that of model A. CONCLUSIONS Based on these results, it was found that bilateral pedicle screw fixation in 2 vertebrae L3 and L5 can achieve similar stability as bilateral pedicle screw fixation in 3 vertebrae L3, L4, and L5. However, the maximum stress of the screw and rod in model B is less than that in model A, so this internal fixation method can effectively reduce the risk of fracture. The 3-dimensional finite element model established in this study is in line with the biomechanical characteristics of the spine and can be used for further studies on spinal column biomechanics. This information can serve as a reference for clinicians for surgical selection.
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Affiliation(s)
- Yulei Ji
- Faculty of Sports Science, Ningbo University, Ningbo, China
| | - Qiaolin Zhang
- Faculty of Sports Science, Ningbo University, Ningbo, China
| | - Yang Song
- Faculty of Sports Science, Ningbo University, Ningbo, China
- Doctoral School on Safety and Security Sciences, Óbuda University, Budapest, Hungary
| | - Qiuli Hu
- Faculty of Sports Science, Ningbo University, Ningbo, China
| | - Gusztáv Fekete
- Savaria Institute of Technology, Eötvös Loránd University, Szombathely, Hungary
| | - Julien S. Baker
- Department of Sport and Physical Education, Hong Kong Baptist University, Hong Kong, China
| | - Yaodong Gu
- Faculty of Sports Science, Ningbo University, Ningbo, China
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Pan A, Ding H, Wang J, Zhang Z, Zhang H, Liu Y, Hai Y. The application of finite element analysis to determine the optimal UIV of growing-rod treatment in early-onset scoliosis. Front Bioeng Biotechnol 2022; 10:978554. [PMID: 36118572 PMCID: PMC9478657 DOI: 10.3389/fbioe.2022.978554] [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] [Received: 06/26/2022] [Accepted: 08/08/2022] [Indexed: 12/04/2022] Open
Abstract
Objectives: To analyze the stress distribution in the proximal vertebral body and soft tissue of dual growing-rod (GR) with different upper instrumented vertebra (UIV) to determine the optimal UIV. Methods: A ten-year-old male EOS case treated with GR was selected. Based on spiral computed tomography (CT) scanning performed in 0.6 mm thick slices, a finite element model (FEM) of the preoperative state (M0, the original spine state) of the patient was created. Subsequently, four models with different UIV fixations were numerically analyzed by FEM, including M1 (UIV = T1, i.e., the upper-end vertebrae (UEV) of the upper thoracic curve), M2 (UIV = T2), M3 (UIV = T3) and M4 (UIV = T4, i.e., the lower end vertebrae (LEV) of the upper thoracic curve). Displacement and maximum stress in the proximal vertebral body and soft tissue were measured and compared among the five models. Results: The spine model was fixed with the sacrum, and the gravity conditions were imposed on each vertebral body according to the research of Clin and Pearsall. The results are as follows:M4 model has the largest overall displacement, while M1 has the least displacement among the four models. Except M2, the maximum normalized stress of UIV increases with the downward movement of UIV. M1 has the lowerest annulus fibrosus stress and highest joint capsule stress, which is characterized by the vertebrae backward leaning, while M4 is the opposite. The supraspinous ligament stress of M3 and M4 is significantly higher than that of M1 and M2. This suggests that UIV downshift increases the tendency of the proximal vertebral bodies to bend forward, thereby increasing the tension of the posterior ligaments (PL). Conclusion: The UIV of the GR is recommended to be close to the UEV of the upper thoracic curve, which can reduce the stress of the proximal PL, thereby reducing the occurrence of proximal junctional kyphosis (PJK).
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Affiliation(s)
- Aixing Pan
- Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Hongtao Ding
- Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Junjie Wang
- School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, China
| | - Zhuo Zhang
- School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, China
| | - Hongbo Zhang
- School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, China
| | - Yuzeng Liu
- Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
- *Correspondence: Yong Hai, ; Yuzeng Liu,
| | - Yong Hai
- Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
- *Correspondence: Yong Hai, ; Yuzeng Liu,
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Kahaer A, Maimaiti X, Maitirouzi J, Wang S, Shi W, Abuduwaili N, Zhou Z, Liu D, Maimaiti A, Rexiti P. Biomechanical investigation of the hybrid modified cortical bone screw–pedicle screw fixation technique: Finite-element analysis. Front Surg 2022; 9:911742. [PMID: 35923441 PMCID: PMC9339714 DOI: 10.3389/fsurg.2022.911742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 06/28/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundHybrid fixation techniques including the both modified cortical bone trajectory (MCBT) and traditional trajectory (TT) at the L4 and L5 lumbar segment are firstly proposed by our team. Therefore, the purpose of this study is to evaluate and provide specific biomechanical data of the hybrid fixation techniques including the MCBT and TT.MethodsFour human cadaveric specimens were from the anatomy laboratory of Xinjiang Medical University. Four finite-element (FE) models of the L4–L5 lumbar spine were generated. For each of them, four implanted models with the following fixations were established: TT-TT (TT screw at the cranial and caudal level), MCBT-MCBT (MCBT screw at the cranial and caudal level), hybrid MCBT-TT (MCBT screw at the cranial level and TT screw at the caudal level), and TT-MCBT (TT screw at the cranial level and MCBT screw at the caudal level). A 400-N compressive load with 7.5 N/m moments was applied to simulate flexion, extension, lateral bending, and rotation, respectively. The range of motion (ROM) of the L4–L5 segment and the posterior fixation, the von Mises stress of the intervertebral disc, and the posterior fixation were compared.ResultsCompared to the TT-TT group, the MCBT-TT showed a significant lower ROM of the L4–L5 segment (p ≤ 0.009), lower ROM of the posterior fixation (p < 0.001), lower intervertebral disc stress (p < 0.001), and lower posterior fixation stress (p ≤ 0.041). TT-MCBT groups showed a significant lower ROM of the L4–L5 segment (p ≤ 0.012), lower ROM of the posterior fixation (p < 0.001), lower intervertebral disc stress (p < 0.001), and lower posterior fixation stress (p ≤ 0.038).ConclusionsThe biomechanical properties of the hybrid MCBT-TT and TT-MCBT techniques at the L4–L5 segment are superior to that of stability MCBT-MCBT and TT-TT techniques, and feasibility needs further cadaveric study to verify.
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Affiliation(s)
- Alafate Kahaer
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Xieraili Maimaiti
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | | | - Shuiquan Wang
- Department of Anatomy, College of Basic Medicine, Xinjiang Medical University, Urumqi, China
| | - Wenjie Shi
- First Clinical Medical College, Xinjiang Medical University, Urumqi, China
| | - Nueraihemaiti Abuduwaili
- Department of Imaging Center, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Zhihao Zhou
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Dongshan Liu
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Abulikemu Maimaiti
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Paerhati Rexiti
- Department of Spine Surgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
- Correspondence: Paerhati Rexiti
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