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Karadag MK, Akgun MY, Basak AT, Ates O, Tepebasili MA, Gunerbuyuk C, Oktenoglu T, Sasani M, Ozer AF. Clinical and radiological analysis of the effects of three different lumbar transpedicular dynamic stabilization system on disc degeneration and regeneration. Front Surg 2023; 10:1297790. [PMID: 38162089 PMCID: PMC10757836 DOI: 10.3389/fsurg.2023.1297790] [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: 09/20/2023] [Accepted: 11/17/2023] [Indexed: 01/03/2024] Open
Abstract
Objective This study aims to assess the clinical outcomes of three transpedicular dynamic systems in treating degenerative disc disease and evaluate their impact on both clinical and radiological aspects of the operated and adjacent segments. Materials and methods A total of 111 patients who underwent posterior transpedicular short-segment dynamic system procedures for treatment of degenerative disc disease were included. The patients were categorized into three groups, namely, Group 1 (Dynesys system, n = 38), Group 2 (Safinaz screw + PEEK rod, n = 37), and Group 3 (Safinaz screw + titanium rod, n = 36). Disc regeneration in the operated segment and disc degeneration in the operated, upper, and lower adjacent segments were assessed using the Pfirrmann Classification. Results Postoperatively, a statistically significant difference was observed in visual analog scale and Oswestry Disability Index scores (p < 0.001). However, no statistically significant difference was seen in disc degeneration/regeneration and degeneration scores of the upper and lower adjacent segments between the preoperative and postoperative groups (p = 0.763, p = 0.518, p = 0.201). Notably, a positive effect on disc regeneration at the operated level (32.4%) was observed. No significant differences were found between the groups in terms of operation rates, screw loosening, and screw breakage after adjacent segment disease (p > 0.05). Conclusion In patients without advanced degeneration, all three dynamic systems demonstrated the ability to prevent degeneration in the adjacent and operated segments while promoting regeneration in the operated segment. Beyond inhibiting abnormal movement in painful segments, maintaining physiological motion and providing axial distraction in the operated segment emerged as key mechanisms supporting regeneration.
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Affiliation(s)
| | - Mehmet Yigit Akgun
- Department of Neurosurgery, Koc University Hospital, Istanbul, Türkiye
- Spine Center, Koc University Hospital, Istanbul, Türkiye
| | | | - Ozkan Ates
- Department of Neurosurgery, Koc University Hospital, Istanbul, Türkiye
- Spine Center, Koc University Hospital, Istanbul, Türkiye
| | | | | | - Tunc Oktenoglu
- Department of Neurosurgery, Koc University Hospital, Istanbul, Türkiye
- Spine Center, Koc University Hospital, Istanbul, Türkiye
| | - Mehdi Sasani
- Department of Neurosurgery, Koc University Hospital, Istanbul, Türkiye
- Spine Center, Koc University Hospital, Istanbul, Türkiye
| | - Ali Fahir Ozer
- Department of Neurosurgery, Koc University Hospital, Istanbul, Türkiye
- Spine Center, Koc University Hospital, Istanbul, Türkiye
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2
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Knapik GG, Mendel E, Bourekas E, Marras WS. Computational lumbar spine models: A literature review. Clin Biomech (Bristol, Avon) 2022; 100:105816. [PMID: 36435080 DOI: 10.1016/j.clinbiomech.2022.105816] [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: 07/28/2022] [Revised: 10/26/2022] [Accepted: 11/08/2022] [Indexed: 11/15/2022]
Abstract
BACKGROUND Computational spine models of various types have been employed to understand spine function, assess the risk that different activities pose to the spine, and evaluate techniques to prevent injury. The areas in which these models are applied has expanded greatly, potentially beyond the appropriate scope of each, given their capabilities. A comprehensive understanding of the components of these models provides insight into their current capabilities and limitations. METHODS The objective of this review was to provide a critical assessment of the different characteristics of model elements employed across the spectrum of lumbar spine modeling and in newer combined methodologies to help better evaluate existing studies and delineate areas for future research and refinement. FINDINGS A total of 155 studies met selection criteria and were included in this review. Most current studies use either highly detailed Finite Element models or simpler Musculoskeletal models driven with in vivo data. Many models feature significant geometric or loading simplifications that limit their realism and validity. Frequently, studies only create a single model and thus can't account for the impact of subject variability. The lack of model representation for certain subject cohorts leaves significant gaps in spine knowledge. Combining features from both types of modeling could result in more accurate and predictive models. INTERPRETATION Development of integrated models combining elements from different model types in a framework that enables the evaluation of larger populations of subjects could address existing voids and enable more realistic representation of the biomechanics of the lumbar spine.
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Affiliation(s)
- Gregory G Knapik
- Spine Research Institute, The Ohio State University, 210 Baker Systems, 1971 Neil Avenue, Columbus, OH 43210, USA.
| | - Ehud Mendel
- Department of Neurosurgery, Yale University, New Haven, CT 06510, USA
| | - Eric Bourekas
- Department of Radiology, The Ohio State University, Columbus, OH 43210, USA
| | - William S Marras
- Spine Research Institute, The Ohio State University, 210 Baker Systems, 1971 Neil Avenue, Columbus, OH 43210, USA
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3
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Karadağ MK, Akıncı AT, Başak AT, Hekimoğlu M, Yıldırım H, Akyoldaş G, Aydın AL, Ateş Ö, Öktenoğlu T, Sasani M, Akgün MY, Günerbüyük C, Özer AF. Preoperative Magnetic Resonance Imaging Abnormalities Predictive of Lumbar Herniation Recurrence After Surgical Repair. World Neurosurg 2022; 165:e750-e756. [PMID: 35803567 DOI: 10.1016/j.wneu.2022.06.143] [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: 04/11/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 12/14/2022]
Abstract
OBJECTIVE There are currently no standard criteria for evaluating the risk of recurrent disk herniation after surgical repair. This study investigated the predictive values of 5 presurgical imaging parameters: paraspinal muscle quality, annular tear size, Modic changes, modified Phirrmann disk degeneration grade, and presence of sacralization or fusion. METHODS Between 2015 and 2018, 188 patients (89 female, 99 male, median age 50) receiving first corrective surgery for lumbar disk herniation were enrolled. Microdiskectomy was performed in 161 of these patients, and endoscopic translaminar diskectomy approach was performed in 27 patients. Clinical status was evaluated before surgery and 4, 12, and 24 months post surgery using a visual analog scale, Oswestry Disability Index, and Short Form 36. RESULTS Recurrent disk herniation was observed in 21 of 188 patients. Seventeen of the recurrent disk herniations were seen in those who underwent microdiskectomy and 4 in those who underwent endoscopic translaminar diskectomy. There were significant differences in visual analog scale, Oswestry Disability Index, and Short Form 36 scores at 4, 12, and 24 months between patients with recurrence and the 167 no-recurrence patients. The median annular tear length was significantly greater in patients with recurrence than without recurrence. In addition, there were significant differences in recurrence rate according to Modic change type distribution, sacralization or fusion presence, Pfirmann disk; degeneration grade distribution, dichotomized annular tear size, dichotomized Modic change; and type and simplified 3-tier muscle degeneration classification distribution. CONCLUSIONS Patients with poor clinical scores and recurrence exhibited additional radiologic abnormalities before surgery, such as poor paraspinal muscle quality, longer annular tears, higher Modic change type, higher modified Phirrmann disk degeneration grade, and sacralization or fusion. This risk evaluation protocol may prove valuable for patient selection, surgical planning, and choice of postoperative recovery regimen.
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Affiliation(s)
| | - Ahmet Tolgay Akıncı
- Neurosurgery Department, Trakya University School of Medicine, Edirne, Turkey
| | | | - Mehdi Hekimoğlu
- Neurosurgery Department, American Hospital, Istanbul, Turkey
| | - Hakan Yıldırım
- Radiology Department, American Hospital, Istanbul, Turkey
| | - Göktuğ Akyoldaş
- Neurosurgery Department, Koc University School of Medicine, Istanbul, Turkey
| | - Ahmet Levent Aydın
- Neurosurgery Department, Koc University School of Medicine, Istanbul, Turkey
| | - Özkan Ateş
- Neurosurgery Department, Koc University School of Medicine, Istanbul, Turkey
| | - Tunç Öktenoğlu
- Neurosurgery Department, American Hospital, Istanbul, Turkey; Neurosurgery Department, Koc University School of Medicine, Istanbul, Turkey
| | - Mehdi Sasani
- Neurosurgery Department, American Hospital, Istanbul, Turkey; Neurosurgery Department, Koc University School of Medicine, Istanbul, Turkey
| | - Mehmet Yiğit Akgün
- Neurosurgery Department, Koc University School of Medicine, Istanbul, Turkey
| | - Caner Günerbüyük
- Orthopedics Department, Koc University School of Medicine, Istanbul, Turkey
| | - Ali Fahir Özer
- Neurosurgery Department, American Hospital, Istanbul, Turkey; Neurosurgery Department, Koc University School of Medicine, Istanbul, Turkey.
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4
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Sengul E, Ozmen R, Demir T. The effects of pre-stressed rods contoured by different bending techniques on posterior instrumentation of L4-L5 lumbar spine segment: A finite element study. Proc Inst Mech Eng H 2022; 236:960-972. [DOI: 10.1177/09544119221096582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Posterior pedicle screw instrumentation (PPSI) is a well-known method in lumbar spine surgery. Understanding how PPSI affects the biomechanics of the lumbar spine is an important issue. In particular, during PPSI operations, surgeons bend rods according to the patients’ spinal curvatures based on their own experiences. As a result, residual stresses develop on the rods due to this bending. Although many finite element-based biomechanical studies have been performed for PPSI, studies comparing the effects of residual stresses arising from rod contouring on the construct stresses are lacking. Thus, this study aimed to investigate the effects of residual stress in PPSI using rods contoured with a French bender and an in-situ bender, as well as comparing the differences in stress increment with straight and contoured rods for different physiological motions. Accordingly, a finite element (FE) model of the L4-L5 lumbar spine segment was developed for PPSI and the effects of residual stresses on rods were investigated by using different bending methods. In the simulations, it was found that rods contoured with a French bender with residual stress resulted in significantly more increased stress in PPSI compared to those contoured with an in-situ bender. The results of this study emphasize that increased stress in PPSI due to the residual stresses for different physiological motions may increase the risk of PPSI failures. Additionally, the finite element modeling approach employed here could be used as a fundamental tool for further investigations of topics such as PPSI fatigue life and failure studies.
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Affiliation(s)
- Emre Sengul
- Department of Mechanical Engineering, TOBB University of Economics and Technology, Çankaya, Ankara, Turkey
- Mechanical Engineer, Roketsan Inc., Lalahan, Ankara, Turkey
| | - Ramazan Ozmen
- Department of Mechatronics Engineering, Karabük University, Merkez, Karabük, Turkey
| | - Teyfik Demir
- Department of Mechanical Engineering, TOBB University of Economics and Technology, Çankaya, Ankara, Turkey
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Jain P, Khan MR. Comparison of novel stabilisation device with various stabilisation approaches: A finite element based biomechanical analysis. Int J Artif Organs 2022; 45:514-522. [PMID: 35393885 DOI: 10.1177/03913988221088334] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The treatment of spinal failure requires suitable instrumentation, which is based on numerous concepts such as rigid fixation, semi-rigid and dynamic stabilisation. In the present work, the biomechanical investigation of various fixation systems on the lumbar segment L2-L3 was performed employing finite element analysis. Different devices were considered: novel stabilisation device (NSD), rigid implant (RI) and existing dynamic stabilisation device (EDSD). All instrumented models were loaded with a condition of 400 N compressive force with a moment of 10Nm during flexion, extension, lateral bending and axial rotation. The results of range of motion change (RMC), von-Mises stress and strain were compared. The spinal biomechanics post instrumentation resulted significantly sensitive to the geometrical feature of the implant. The obtained results showed that NSD has intermediate motion characteristics in between dynamic stabilisation and rigid fixation. However, the optimum features of a novel stabilisation device for the treatment of spinal failure still need to be verified employing in-vivo, in-vitro studies.
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Affiliation(s)
- Pushpdant Jain
- School of Mechanical Engineering, VIT Bhopal University, Sehore, Madhya Pradesh, India
| | - Mohammed Rajik Khan
- Department of Industrial Design, National Institute of Technology Rourkela, Rourkela, Odisha, India
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Sengul E, Ozmen R, Yaman ME, Demir T. Influence of posterior pedicle screw fixation at L4-L5 level on biomechanics of the lumbar spine with and without fusion: a finite element method. Biomed Eng Online 2021; 20:98. [PMID: 34620170 PMCID: PMC8499536 DOI: 10.1186/s12938-021-00940-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 09/24/2021] [Indexed: 12/27/2022] Open
Abstract
Background Posterior pedicle screw (PS) fixation, a common treatment method for widespread low-back pain problems, has many uncertain aspects including stress concentration levels, effects on adjacent segments, and relationships with physiological motions. A better understanding of how posterior PS fixation affects the biomechanics of the lumbar spine is needed. For this purpose, a finite element (FE) model of a lumbar spine with posterior PS fixation at the L4–L5 segment level was developed by partially removing facet joints (FJs) to imitate an actual surgical procedure. This FE study aimed to investigate the influence of the posterior PS fixation system on the biomechanics of the lumbar spine before and after fusion by determining which physiological motions have the most increase in posterior instrumentation (PI) stresses and FJ loading. Results It was determined that posterior PS fixation increased FJ loading by approximately 35% and 23% at the L3–L4 adjacent level with extension and lateral bending motion, respectively. This increase in FJ loading at the adjacent level could point to the possibility that adjacent segment disease has developed or progressed after posterior lumbar interbody fusion. Furthermore, analyses of peak von Mises stresses on PI showed that the maximum PI stresses of 272.1 MPa and 263.7 MPa occurred in lateral bending and flexion motion before fusion, respectively. Conclusions The effects of a posterior PS fixation system on the biomechanics of the lumbar spine before and after fusion were investigated for all physiological motions. This model could be used as a fundamental tool for further studies, providing a better understanding of the effects of posterior PS fixation by clearing up uncertain aspects.
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Affiliation(s)
- Emre Sengul
- Department of Mechanical Engineering, TOBB University of Economics and Technology, Çankaya, Ankara, Turkey. .,Mechanical Engineer, Roketsan Inc., Lalahan, 06852, Ankara, Turkey.
| | - Ramazan Ozmen
- Department of Mechanical Engineering, Karabük University, Merkez, Karabük, Turkey
| | - Mesut Emre Yaman
- Department of Neurosurgery, Gazi University School of Medicine, Ankara, Turkey
| | - Teyfik Demir
- Department of Mechanical Engineering, TOBB University of Economics and Technology, Çankaya, Ankara, Turkey
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Kang J, Dong E, Li X, Guo Z, Shi L, Li D, Wang L. Topological design and biomechanical evaluation for 3D printed multi-segment artificial vertebral implants. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 127:112250. [PMID: 34225889 DOI: 10.1016/j.msec.2021.112250] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 05/02/2021] [Accepted: 06/07/2021] [Indexed: 12/11/2022]
Abstract
Customized spinal implants fabricated by additive manufacturing have been increasingly used clinically to restore the physiological functions. However, the mechanisms and methods about the design for the spinal implants are not clear, especially for the reconstruction of multi-segment vertebral. This study aims to develop a novel multi-objective optimization methodology based on various normal spinal activities, to design the artificial vertebral implant (AVI) with lightweight, high-strength and high-stability. The biomechanical performance for two types of AVI was analyzed and compared under different loading conditions by finite element method. These implants were manufactured via selective laser melting technology and evaluated via compressive testing. Results showed the maximum Mises stress of the optimized implant under various load cases were about 41.5% of that of the trussed implant, and below fatigue strength of 3D printed titanium materials. The optimized implant was about 2 times to trussed implant in term of the maximum compression load and compression stiffness to per unit mass, which indicated the optimized implant can meet the safety requirement. Finally, the optimized implant has been used in clinical practice and good short-term clinical outcomes were achieved. Therefore, the novel developed method provides a favorable guarantee for the design of 3D printed multi-segment artificial vertebral implants.
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Affiliation(s)
- Jianfeng Kang
- Jihua Laboratory, Foshan, Guangdong, China; State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaan Xi, China
| | - Enchun Dong
- State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaan Xi, China
| | - Xiangdong Li
- Department of Orthopedics, Xijing Hospital, Air Force Medical University of PLA, Xi'an, Shaan Xi, China
| | - Zheng Guo
- Department of Orthopedics, Xijing Hospital, Air Force Medical University of PLA, Xi'an, Shaan Xi, China
| | - Lei Shi
- Department of Orthopedics, Xijing Hospital, Air Force Medical University of PLA, Xi'an, Shaan Xi, China
| | - Dichen Li
- Jihua Laboratory, Foshan, Guangdong, China; State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaan Xi, China; Guangdong Xi'an Jiaotong University Academy, Guangdong, China.
| | - Ling Wang
- State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaan Xi, China.
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8
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Özer AF, Aydın AL, Hekimoğlu M, Çerezci Ö, Başak AT, Ates O, Oktenoglu T, Sasani M. Should Iliac Wing Screws Be Included in Long Segment Dynamic Stabilization? Cureus 2021; 13:e13543. [PMID: 33815968 PMCID: PMC8009454 DOI: 10.7759/cureus.13543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Background In this article, clinical satisfaction and radiological results are discussed in a series of patients where the iliac wings participate in dynamic stabilization. Dynamic stabilization is an effective alternative surgical treatment method, especially in clinical pictures that go with pain due to minor instabilities. Practically the unique surgical instrument used in multilevel instabilities is the Dynesys system. The most important drawback of the Dynesys system is that the S1 screws become loose in time. In this article, our aim is to find solution to S1 insufficiency by extension of the system to the iliac wings. Methods Nineteen patients (eight females, 11 males) with a mean age of 54.16 were included in the study. Patients had multilevel (level 2 and above) instability, iliac wings were included in the stabilized segments, and Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) were used for patient follow-up. Results First year results showed a significant improvement in VAS and ODI. Regarding the complications, infection developed in one patient, loosening in the proximal iliac wing in one patient, and both S1 and iliac proximals in one patient, but no clinical findings were encountered. Conclusion When more than two levels of dynamic systems are used in chronic instability, especially in the elderly patients, S1 screws are loosened. In these patients, if the iliac bones are also included in stabilization, this problem is solved successfully. However unfortunately, Dynesys system does not have a screw suitable for the iliac bones.
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Affiliation(s)
- Ali Fahir Özer
- Neurosurgery, Koç University School of Medicine, Istanbul, TUR
| | | | | | - Önder Çerezci
- Physical Treatment and Rehabilitation, American Hospital, Istanbul, TUR
| | | | - Ozkan Ates
- Neurosurgery, Koç University School of Medicine, Istanbul, TUR
| | - Tunc Oktenoglu
- Neurosurgery, Koç University School of Medicine, Istanbul, TUR
| | - Mehdi Sasani
- Neurosurgery, Koç University School of Medicine, Istanbul, TUR
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9
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Wang H, Wan Y, Liu X, Ren B, Xia Y, Liu Z. The biomechanical effects of Ti versus PEEK used in the PLIF surgery on lumbar spine: a finite element analysis. Comput Methods Biomech Biomed Engin 2021; 24:1115-1124. [PMID: 33427508 DOI: 10.1080/10255842.2020.1869219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Titanium (Ti) and polyetheretherketone (PEEK) are commonly used in posterior lumbar interbody fusion (PLIF). The study investigated biomechanical effects of Ti versus PEEK used as materials of cage and rods on the lumbar spine. Four different configurations of PLIF were constituted. Stiff Ti rods provided satisfactory initial stability but increased the stress on rods significantly under simulated physiological load conditions. Ti cage increased the stress on bone endplates significantly. Materials of cage and rods had insignificant effects on the nucleus pressure and facet joint force of non-instrumented segments. Further clinical studies and follow-up observations are essential for corroborating these findings.
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Affiliation(s)
- Hongwei Wang
- Key Laboratory of High Efficiency and Clean Manufacturing, School of Mechanical Engineering, Shandong University, Jinan, China.,National Demonstration Center for Experimental Mechanical Engineering Education, School of Mechanical Engineering, Shandong University, Jinan, China
| | - Yi Wan
- Key Laboratory of High Efficiency and Clean Manufacturing, School of Mechanical Engineering, Shandong University, Jinan, China.,National Demonstration Center for Experimental Mechanical Engineering Education, School of Mechanical Engineering, Shandong University, Jinan, China
| | - Xinyu Liu
- Department of Orthopedics, Qilu Hospital of Shandong University, Jinan, China
| | - Bing Ren
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA
| | - Yan Xia
- Key Laboratory of High Efficiency and Clean Manufacturing, School of Mechanical Engineering, Shandong University, Jinan, China.,National Demonstration Center for Experimental Mechanical Engineering Education, School of Mechanical Engineering, Shandong University, Jinan, China
| | - Zhanqiang Liu
- Key Laboratory of High Efficiency and Clean Manufacturing, School of Mechanical Engineering, Shandong University, Jinan, China.,National Demonstration Center for Experimental Mechanical Engineering Education, School of Mechanical Engineering, Shandong University, Jinan, China
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10
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Yin JY, Guo LX. Biomechanical analysis of lumbar spine with interbody fusion surgery and U-shaped lumbar interspinous spacers. Comput Methods Biomech Biomed Engin 2020; 24:1-11. [PMID: 33241697 DOI: 10.1080/10255842.2020.1851368] [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: 08/01/2020] [Revised: 10/11/2020] [Accepted: 11/11/2020] [Indexed: 10/22/2022]
Abstract
Previous research indicates whole-body vibration may lead to low back pain. The aim of this study is assessing the dynamic characteristics of a lumbar spine with Coflex and Coflex-F (commercial implants used as lumbar interspinous spacers) and effect of lumbar interbody fusion surgery. A transient dynamic analysis is performed on three numerical lumbar spine models under the loading condition of a vertical sinusoidal force of ±40 N with a compressive follower preload of 400 N. Also, Coflex-F model with and without interbody fusion surgery is analyzed under the same loading condition. The results show that the maximum value and vibration amplitude of von Mises stress in annulus ground substance (AGS) and intradiscal pressure (IDP) at implanted segment decrease from healthy model to Coflex model, and Coflex-F model. By contrast, for adjacent segments the maximum value of implanted models are larger than that of healthy model. The maximum value of endplates with and without cage are 2.44 MPa and 1.73 MPa (L4 inferior endplate), 1.94 MPa and 1.42 MPa (L5 superior endplate), respectively. The vibration amplitude of Coflex-F model with fusion surgery is smaller than that without fusion surgery. Coflex and Coflex-F not only protect implanted segment but also have a negative effect on adjacent segments. Inserting cage for Coflex-F model can absorb vibration energy at adjacent segments.
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Affiliation(s)
- Jia-Yu Yin
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
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11
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Fan W, Guo LX. The effect of non-fusion dynamic stabilization on biomechanical responses of the implanted lumbar spine during whole-body vibration. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 192:105441. [PMID: 32172078 DOI: 10.1016/j.cmpb.2020.105441] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/07/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND OBJECTIVE Non-fusion dynamic stabilization surgery is increasingly popular for treating degenerative lumbar disc disease. However, changes in spine biomechanics after application of posterior dynamic fixation devices during whole-body vibration (WBV) remain unclear. The study aimed to examine the effects of non-fusion dynamic stabilization on biomechanical responses of the implanted lumbar spine to vertical WBV. METHODS By modifying L4-L5 segment of the healthy human L1-sacrum finite element model, single-level disc degeneration, dynamic fixation using the BioFlex system and anterior lumbar interbody fusion (ALIF) with rigid fixation were simulated, respectively. Dynamic responses of stress and strain in the spinal levels for the healthy, degenerated, BioFlex and ALIF models under an axial cyclic loading were investigated and compared. RESULTS The results showed that endplate stress at implant level was lower in the BioFlex model than in the degenerated and ALIF models, but stress of the connecting rod in the BioFlex system was greater than that in the rigid fixation system used in the ALIF. Compared with the healthy model, stress and strain responses in terms of disc bulge, annulus stress and nucleus pressure at adjacent levels were decreased in the degenerated, BioFlex and ALIF models, but no obvious difference was observed in these responses among the three models. CONCLUSIONS This study may be helpful to understand variations in vibration characteristics of the lumbar spine after application of non-fusion dynamic stabilization system.
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Affiliation(s)
- Wei Fan
- School of Mechanical Engineering and Automation, Northeastern University, No. 3-11, Wenhua Road, Heping District, Shenyang, 110819, China.
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, No. 3-11, Wenhua Road, Heping District, Shenyang, 110819, China
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12
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Jain P, Rana M, Biswas JK, Khan MR. Biomechanics of spinal implants-a review. Biomed Phys Eng Express 2020; 6:042002. [PMID: 33444261 DOI: 10.1088/2057-1976/ab9dd2] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Spinal instrumentations have been classified as rigid fixation, total disc replacement and dynamic stabilization system for treatment of various spinal disorders. The efficacy and biomechanical suitability of any spinal implant can be measured through in vitro, in vivo experiments and numerical techniques. With the advancement in technology finite element models are making an important contribution to understand the complex structure of spinal components along with allied functionality, designing and application of spinal instrumentations at preliminary design stage. This paper aimed to review the past and recent studies to describe the biomechanical aspects of various spinal implants. The literatures were grouped and reviewed in accordance to instrumentation category and their functionality in the spinal column at respective locations.
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Affiliation(s)
- Pushpdant Jain
- School of Mechanical Engineering, VIT Bhopal University, Bhopal-Indore Highway Kothrikalan, Sehore Madhya Pradesh - 466114, India
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13
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Mesbah M, Barkaoui A. Biomechanical investigation of the effect of pedicle-based hybrid stabilization constructs: A finite element study. Proc Inst Mech Eng H 2020; 234:931-941. [PMID: 32597299 DOI: 10.1177/0954411920934956] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Hybrid stabilization is widely performed for the surgical treatment of degenerative disk diseases. Pedicle-based hybrid stabilization intends to reduce fusion-associated drawbacks of adjacent segment degeneration, construct failure, and pseudoarthrosis. Recently, many types of pedicle-based hybrid stabilization systems have been developed and optimized, using polymeric devices as an adjunct for lumbar fusion procedures. Therefore, the purpose of this study was to evaluate the effect of new pedicle-based hybrid stabilization on bending stiffness and center of rotation at operated and adjacent levels in comparison with established semirigid and rigid devices in lumbar fusion procedures. A validated three-dimensional finite element model of the L3-S1 segments was modified to simulate postoperative changes during combined loading (moment of 7.5 N m + follower load of 400 N). Two models instrumented with pedicle-based hybrid stabilization (Dynesys Transition Optima, NFlex), semirigid system (polyetheretherketone), and rigid fixation system (titanium rod (Ti) were compared with those of the healthy and degenerated models. Contact force on the facet joint during extension increased in fusion (40 N) with an increase of bending stiffness in Dynesys and NFlex. The center of rotation shifted in posterior and cranial directions of the fused level. The centers of rotation in the lower lumbar spine is segment dependent and altered with the adopted construct. The bending stiffness was varied from 1.47 N m/° in lateral bending for the healthy model to 5.75 N m/° for the NFlex stabilization, which had the closest center of rotation, compared to the healthy center of rotation. Locations of center of rotation, stress, and strain distribution varied according to construct design and materials used. These data could help understand the biomechanical effects of current pedicle-based hybrid stabilization on the behavior of the lower lumbar spine.
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Affiliation(s)
- Moustafa Mesbah
- Laboratory of Numerical and Experimental Modeling of Mechanical Phenomena, Department of Mechanical Engineering, University of Abdelhamid Ibn Badis, Mostaganem, Algeria
| | - Abdelwahed Barkaoui
- Laboratoire des Énergies Renouvelables et Matériaux Avancés, Université Internationale de Rabat (UIR), Rocade de Rabat-Salé, Morocco
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Zhang W, Zhao J, Jiang X, Li L, Yu C, Zhao Y, Si H. Thoracic vertebra fixation with a novel screw-plate system based on computed tomography imaging and finite element method. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 187:104990. [PMID: 31345591 DOI: 10.1016/j.cmpb.2019.104990] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND OBJECTIVE The traditional pedicle screw-rod internal fixation system has been widely used for thoracic diseases in clinical practice, but its high profile increases the damage to soft tissue, leading to long-term intractable back stiffness. The purpose of this study is to compare biomechanical advantages between the new spine pedicle screw-plate internal fixation system and traditional pedicle screw-rod internal fixation system using finite element analysis. METHODS Based on computed tomography (CT), four three-dimensional finite element models of T7-T9 were constructed. The downward concentrated force of 150 N and the moment of 5 Nm was applied to the models to simulate six physiological activities, including flexion, extension, left and right lateral bending, left and right axial torsion. The maximum displacement, range of motion (ROM) and maximum stress of the two models in six physiological activities, was measured to evaluate the biomechanical advantages of the novel pedicle screw-plate internal fixation system. RESULTS The novel pedicle screw-plate internal fixation system has a lower profile than the traditional pedicle screw-rod internal fixation system. With regards to the stability, the maximum displacement of the models of two internal fixation systems decreased by 56.2%-91.4% under the six motion status when comparing with the unstable model. Meanwhile, the ROM remained unchanged between the two models of internal fixation systems besides the left lateral bending. However, there is no significant difference in the ROM between the models of the two internal fixation systems in left lateral bending motion (P = 0.203). In terms of the strength, the maximum stress in the model with the new pedicle screw-plate internal fixation system was higher than that of model with the traditional pedicle screw-rod internal fixation system in every motion status but left and right lateral bending motion. CONCLUSIONS The novel pedicle screw-plate internal fixation system has lower profile in orthopedics and higher strength, However, it has no disadvantage when comparing with the traditional pedicle screw-rod internal fixation system in terms of the stability. In summary, we suggest that the novel spine pedicle screw-plate system can be used as a new internal fixation and provide better comfort for patients.
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Affiliation(s)
- Wencan Zhang
- Qilu Hospital, Shandong University, Jinan 250012, China
| | - Junyong Zhao
- College of Physics and Electronic Sciences, Shandong Normal University, Jinan 250000, China
| | - Xiujuan Jiang
- College of Physics and Electronic Sciences, Shandong Normal University, Jinan 250000, China
| | - Le Li
- Qilu Hospital, Shandong University, Jinan 250012, China
| | - Chenxiao Yu
- Qilu Hospital, Shandong University, Jinan 250012, China
| | - Yuefeng Zhao
- College of Physics and Electronic Sciences, Shandong Normal University, Jinan 250000, China
| | - Haipeng Si
- Qilu Hospital, Shandong University, Jinan 250012, China.
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Gomleksiz C, Erbulut DU, Can H, Kodigudla MK, Kelkar AV, Kasapoglu E, Ozer AF, Goel VK. A new lumbar fixation device alternative to pedicle-based stabilization for lumbar spine: In vitro cadaver investigation. J Spinal Cord Med 2020; 43:98-105. [PMID: 30010500 PMCID: PMC7006719 DOI: 10.1080/10790268.2018.1495932] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Context: To evaluate the stability provided by a new bilateral fixation technique using an in vitro investigation for posterior lumbar segmental instrumentation.Design: Experimental cadaver study. In this study, we propose an alternative technique for a posterior lumbar fixation technique called "inferior-oblique transdiscal fixation" (IOTF).Setting: Study performed at Engineering Center for Orthopedic Research Exellence (ECORE) in Toledo University-Ohio.Participants: Six human lumbar cadaveric specimen used in this study.Interventions: In this study, we propose an alternative technique for a posterior lumbar fixation technique called "inferior-oblique transdiscal fixation" (IOTF). As a novel contribution to the classical technique, the entry point of the screw is the supero-lateral point of the intersecting line drawn between the corpus and the pedicle of the upper vertebra. This approach enables the fixation of two adjacent vertebrae using a single screw on each side without utilizing connecting rods.Outcome Measures: Flexion (Flex), extension (Ext), right and left lateral bending (LB & RB), and right and left axial rotation (LR & RR), and the position data were captured at each load step using the Optotrak motion measurement system and compared for IOTF and posterior transpedicular stabilization.Results: The Posterior stabilization system (PSS) and IOTF significantly reduced the ROM of L4-L5 segment compared to intact segment's ROM. During axial rotation (AR) IOTF fused index segment more than PSS. Besides this, addition of transforaminal lumbar interbody fusion (TLIF) cage improved the stabilization of IOTF system during flexion, extension and lateral bending. Whereas, PSS yielded better fusion results during extension compared to IOTF with and without interbody fusion cages.Conclusions: We hypothesized that the new posterior bilateral system would significantly decrease motion compared to the intact spine. This cadaver study showed that the proposed new posterior fusion technique IOTF fused the index segment in a similar fashion to the classical pedicle screw fusion technique.
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Affiliation(s)
| | - Deniz Ufuk Erbulut
- Engineering Center for Orthopaedic Research Excellence (ECORE), University of Toledo, Toledo, Ohio, USA
| | - Halil Can
- Department of Neurosurgery, Biruni University, Istanbul, Turkey
| | - Manoj Kumar Kodigudla
- Engineering Center for Orthopaedic Research Excellence (ECORE), University of Toledo, Toledo, Ohio, USA
| | - Amey V. Kelkar
- Engineering Center for Orthopaedic Research Excellence (ECORE), University of Toledo, Toledo, Ohio, USA
| | - Eser Kasapoglu
- Department of Computer Assisted Design and Animation Program, Istanbul Medipol University, Istanbul, Turkey
| | - Ali Fahir Ozer
- Department of Neurosurgery, Koc University, Istanbul, Turkey
| | - Vijay K. Goel
- Engineering Center for Orthopaedic Research Excellence (ECORE), University of Toledo, Toledo, Ohio, USA
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Fan W, Guo LX, Zhao D. Stress analysis of the implants in transforaminal lumbar interbody fusion under static and vibration loadings: a comparison between pedicle screw fixation system with rigid and flexible rods. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2019; 30:118. [PMID: 31628540 DOI: 10.1007/s10856-019-6320-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 10/08/2019] [Indexed: 06/10/2023]
Abstract
The use of a pedicle screw fixation system with rods made of more compliant materials has become increasingly popular for spine fusion surgery in recent years. The aim of this study was to compare stress responses of the implants in transforaminal lumbar interbody fusion (TLIF) when using flexible and conventional rigid posterior fixation systems. A previously validated intact L1-S1 finite element model was modified to simulate single-level (L4-L5) TLIF with bilateral pedicle screw fixation using two types of connecting rod (rigid and flexible rods). The von Mises stresses in the implants (including TLIF cage, pedicle screws and rods) for the rigid and flexible fixations were analyzed under static and vibration loadings. The results showed that compared with the rigid fixation, the use of flexible fixation decreased the maximum stress in the pedicle screws, but increased the maximum stress in the cage and the ratio of maximum stress in the rods to the yield stress. It was also found that with decreasing diameter of the flexible rod (i.e. increasing flexibility of the rod), the maximum stress was decreased in the pedicle screws but increased in the cage and the rods. The findings imply that compared with the rigid rod, application of the flexible rod in the pedicle screw fixation system for the TLIF might decrease the breakage risk of pedicle screws but increase the risk of cage subsidence and rod breakage. Moreover, flexibility of the rod in the flexible fixation system should be carefully determined.
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Affiliation(s)
- Wei Fan
- School of Mechanical Engineering and Automation, Northeastern University, No. 3-11, Wenhua Road, Heping District, Shenyang, 110819, China.
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, No. 3-11, Wenhua Road, Heping District, Shenyang, 110819, China
| | - Dan Zhao
- Liaoning University of Traditional Chinese Medicine, Shenyang, China
- Liaoning Special Education Teachers College, Shenyang, China
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17
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Ozer AF, Oktenoglu T, Egemen E, Sasani M, Yilmaz A, Erbulut DU, Yaman O, Suzer T. Lumbar Single-Level Dynamic Stabilization with Semi-Rigid and Full Dynamic Systems: A Retrospective Clinical and Radiological Analysis of 71 Patients. Clin Orthop Surg 2017; 9:310-316. [PMID: 28861198 PMCID: PMC5567026 DOI: 10.4055/cios.2017.9.3.310] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 04/12/2017] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND This study compares the clinical and radiological results of three most commonly used dynamic stabilization systems in the field of orthopedic surgery. METHODS A total of 71 patients underwent single-level posterior transpedicular dynamic stabilization between 2011 and 2014 due to lumbar degenerative disc disease. Three different dynamic systems used include: (1) the Dynesys system; (2) a dynamic screw with a PEEK rod; and (3) a full dynamic system (a dynamic screw with a dynamic rod; BalanC). The mean patient age was 45.8 years. The mean follow-up was 29.7 months. Clinical and radiological data were obtained for each patient preoperatively and at 6, 12, and 24 months of follow-up. RESULTS Clinical outcomes were significantly improved in all patients. There were no significant differences in the radiological outcomes among the groups divided according to the system used. Screw loosening was detected in 2 patients, and 1 patient developed screw breakage. All patients with screw loosening or breakage underwent revision surgery. CONCLUSIONS Each procedure offered satisfactory outcome regardless of which system was applied.
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Affiliation(s)
- Ali Fahir Ozer
- Department of Neurosurgery, Koc University School of Medicine, Istanbul, Turkey
| | - Tunc Oktenoglu
- Department of Neurosurgery, Koc University School of Medicine, Istanbul, Turkey
| | - Emrah Egemen
- Department of Neurosurgery, Koc University School of Medicine, Istanbul, Turkey
| | - Mehdi Sasani
- Department of Neurosurgery, Koc University School of Medicine, Istanbul, Turkey
| | - Atilla Yilmaz
- Department of Neurosurgery, Mustafa Kemal University, Hatay, Turkey
| | - Deniz Ufuk Erbulut
- Department of Biomedical Engineering, Medipol University, Istanbul, Turkey
| | - Onur Yaman
- Department of Neurosurgery, Koc University School of Medicine, Istanbul, Turkey
| | - Tuncer Suzer
- Department of Neurosurgery, Koc University School of Medicine, Istanbul, Turkey
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