FINITE ELEMENT ANALYSIS OF CERVICAL SPINE WITH DIFFERENT CONSTRAINED TYPES OF TOTAL DISC REPLACEMENT

2014 ◽  
Vol 14 (03) ◽  
pp. 1450038 ◽  
Author(s):  
CHIEN-YU LIN ◽  
SHIH-YOUENG CHUANG ◽  
CHANG-JUNG CHIANG ◽  
YANG-HWEI TSUANG ◽  
WENG-PIN CHEN
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Vertebral Body ◽  
Facet Joint ◽  
Total Disc Replacement ◽  
Axial Rotation ◽  
Disc Replacement ◽  
Normal Person ◽  
Fe Model ◽  
Segmental Motion

Various designs of cervical total disc replacement (CTDR) have been introduced and employed in an attempt to avoid disadvantages of the fusion surgery. The purposes of this study were to evaluate the effects of the range of motion (ROM), the instantaneous center of rotation (ICR) and the facet joint force (FJF) with different constrained types of CTDR devices. A three-dimensional finite element (FE) model of intact cervical spine (C3-7) was made from CT scans of a normal person and validated. Postoperative FE models simulating CTDR implantation at the C5-6 disc space were made for CTDR-I (constrained design) and CTDR-II (nonconstrained design), respectively. Hybrid protocol (intact: 1 Nm) with a compressive follower load of 73.6 N was applied at the superior endplate of the C3 vertebral body. The inferior endplate of C7 vertebral body was constrained in all directions. At the index level, CTDR-I showed a higher increase in segmental motion and FJF than CTDR-II in extension, lateral bending and axial rotation. The CTDR-II with an elastomer-type core reproduced a near physiological ICR of the intact model in extension and axial rotation. Abnormal kinetic and kinematic changes related to the CTDR may induce surgical level problems and cause long-term failure of spinal surgery.

Effects of Removal of Uncinate Process in a Cervical Disc Replacement Model: A Finite Element Based Study

2007 ◽  
Author(s):  
A. Faizan ◽  
V. K. Goel ◽  
M. Krishna ◽  
T. Friesem
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
General Procedure ◽  
Total Disc Replacement ◽  
Uncinate Process ◽  
Disc Replacement ◽  
Cervical Disc ◽  
Fe Model ◽  
Disc Space ◽  
Cervical Disc Replacement

Anterior surgical approach is commonly used for Total Disc Replacement (TDR) surgeries in the cervical spine. The general procedure includes removal of the nucleus and anterior annulus of the intervertebral disc. Resection of Anterior Longitudinal Ligaments (ALL) is often performed to enter the disc space. The cervical spine also contains a unique anatomical feature called Luschka’s joints. These “joints” are actually fissures in the disc which run approximately parallel to the uncinate processes. These joints are thought to provide biomechanical stability to the cervical spine. However, sometimes surgeons have to sacrifice the uncinate processes at the involved level as well. We hypothesized that the cervical spine loses stability if the uncinate processes are removed along with disc replacement. We used a Finite Element (FE) model of cervical spine to prove the hypothesis (Fig1).

scholarly journals Finite element study on effect of follower load on intersegmental rotation, facet joint force and nucleus pressure of the cervical spine

2019 ◽  
Author(s):  
Xin-Yi Cai ◽  
Chen-Xi Yuchi ◽  
Cheng-Fei Du ◽  
Zhong-Jun Mo
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Facet Joint ◽  
Compressive Load ◽  
Axial Rotation ◽  
Fe Model ◽  
Follower Load ◽  
Joint Force ◽  
Human Spine ◽  
Joint Forces

Abstract Background: The follower load is used to simulate the physiological compressive load of human spine. These compressive loads can maintain cervical spine’s mechanics stability and play a significant role in improving load-carrying capacity of the cervical spine. However, under different follower loads the biomechanical response of the cervical spine is unknown. So the aim of this study is to investigate the effect of follower load on biomechanics of the cervical spine. Results: In this study, a three-dimensional nonlinear finite element (FE) model of the cervical spine (C3-C7) was built and validated. Using this FE model of the cervical spine, we evaluated the effect of different follower loads on intersegmental rotation, facet joint force, and nucleus pressure in the cervical spine. The results indicated that with the follower load increased, the intersegmental rotation of the cervical spine in extension decreased, but the intersegmental rotation in other postures increased. The follower load increased the facet joint forces in all postures. In lateral bending (LB), the facet joint forces were only generated in the ipsilateral facet joints. In axial rotation (AR), there was a large asymmetry in the facet joint forces, and this asymmetry worsened with the follower load increased. The nucleus pressure of each segment nonlinearly increased with the follower load increased in all postures. Conclusion: An comprehensive analysis in intersegmental rotation, facet joint force and nucleus pressure under different follower loads can provide us a deeper understanding of the follower load in the human spine.

Lumbar Spine Capsule Strain After Total Disc Replacement

2010 ◽  
Author(s):  
Tomoyuki Takigawa ◽  
Alejandro A. Espinoza Orías ◽  
Howard S. An ◽  
Peter Simon ◽  
Keizo Sugisaki ◽  
...  
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Facet Joint ◽  
Total Disc Replacement ◽  
Clinical Results ◽  
Disc Replacement ◽  
Segmental Motion ◽  
Low Back ◽  
Disc Disease ◽  
Poor Outcomes

Degenerative disc disease is a common cause for low back pain, and sometimes requires surgical treatment. Total disc replacement (TDR) is one such surgical option performed to remove the painful disc and preserve segmental motion. However, TDR clinical results are not always satisfactory. Altered kinematics and residual low back pain have been reported as frequent poor outcomes. The facet joint is a pure articular joint and can be a pain generator. Although the effect of TDR on ROMs (ranges of motion) and facet contact force is relatively well studied, the influence of TDR on facet capsules has not been clarified yet. The purpose of this study was to evaluate the effect of TDR on facet joint capsule strain.

Numerical investigation on the stability of human upper cervical spine (C1–C3)

2021 ◽  
pp. 1-13
Author(s):  
Waseem Ur Rahman ◽  
Wei Jiang ◽  
Guohua Wang ◽  
Zhijun Li
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Axial Rotation ◽  
Upper Cervical Spine ◽  
Fe Model ◽  
Facet Joints ◽  
Flexion Extension ◽  
Upper Cervical ◽  
The Stability

BACKGROUND: The finite element method (FEM) is an efficient and powerful tool for studying human spine biomechanics. OBJECTIVE: In this study, a detailed asymmetric three-dimensional (3D) finite element (FE) model of the upper cervical spine was developed from the computed tomography (CT) scan data to analyze the effect of ligaments and facet joints on the stability of the upper cervical spine. METHODS: A 3D FE model was validated against data obtained from previously published works, which were performed in vitro and FE analysis of vertebrae under three types of loads, i.e. flexion/extension, axial rotation, and lateral bending. RESULTS: The results show that the range of motion of segment C1–C2 is more flexible than that of segment C2–C3. Moreover, the results from the FE model were used to compute stresses on the ligaments and facet joints of the upper cervical spine during physiological moments. CONCLUSION: The anterior longitudinal ligaments (ALL) and interspinous ligaments (ISL) are found to be the most active ligaments, and the maximum stress distribution is appear on the vertebra C3 superior facet surface under both extension and flexion moments.

WEAR PREDICTION OF THE LUMBAR TOTAL DISC REPLACEMENT USING FINITE ELEMENT METHOD

2016 ◽  
Vol 16 (02) ◽  
pp. 1650004 ◽  
Author(s):  
S. SHANKAR ◽  
D. KESAVAN
Keyword(s):  
Finite Element ◽  
Total Disc Replacement ◽  
International Standards ◽  
Disc Replacement ◽  
Wear Testing ◽  
Fe Model ◽  
Lumbar Total Disc Replacement ◽  
Metal Metal ◽  
International Standards Organization ◽  
Testing Protocols

Wear in the total disc replacement (TDR) is a significant clinical concern which reduces the lifetime of prosthesis. It induces the formation of potentially harmful debris and involves the risks of a new surgical operation. The objective of this paper is to estimate the wear using finite element (FE) concepts considering various combination of materials: metal-polymer, ceramic–ceramic and metal–metal bearing couples for lumbar total disc replacement (LTDR). The FE model was subjected to wear testing protocols according to loading profile of International Standards Organization (ISO) 18192 standards up to 10 million cycles. The present study revealed that, Alumina–Alumina (Al2O3–Al2O3) bearing pair is suitable one for the TDR process because of less volumetric wear, hence it could be considered in LTDR designs.

A Novel Anterior Transpedicular Screw Artificial Vertebral Body System for Lower Cervical Spine Fixation: A Finite Element Study

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Weidong Wu ◽  
Chun Chen ◽  
Jinpei Ning ◽  
Peidong Sun ◽  
Jinyuan Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Vertebral Body ◽  
Facet Joint ◽  
Lower Cervical Spine ◽  
Body System ◽  
Joint Force ◽  
Transpedicular Screw ◽  
Spine Model ◽  
Artificial Vertebral Body

A finite element model was used to compare the biomechanical properties of a novel anterior transpedicular screw artificial vertebral body system (AVBS) with a conventional anterior screw plate system (ASPS) for fixation in the lower cervical spine. A model of the intact cervical spine (C3–C7) was established. AVBS or ASPS constructs were implanted between C4 and C6. The models were loaded in three-dimensional (3D) motion. The Von Mises stress distribution in the internal fixators was evaluated, as well as the range of motion (ROM) and facet joint force. The models were generated and analyzed by mimics, geomagic studio, and ansys software. The intact model of the lower cervical spine consisted of 286,382 elements. The model was validated against previously reported cadaveric experimental data. In the ASPS model, stress was concentrated at the connection between the screw and plate and the connection between the titanium mesh and adjacent vertebral body. In the AVBS model, stress was evenly distributed. Compared to the intact cervical spine model, the ROM of the whole specimen after fixation with both constructs is decreased by approximately 3 deg. ROM of adjacent segments is increased by approximately 5 deg. Facet joint force of the ASPS and AVBS models was higher than those of the intact cervical spine model, especially in extension and lateral bending. AVBS fixation represents a novel reconstruction approach for the lower cervical spine. AVBS provides better stability and lower risk for internal fixator failure compared with traditional ASPS fixation.

Failure analysis of C-5 after total disc replacement with ProDisc-C at 1 and 2 levels and in combination with a fusion cage: finite-element and biomechanical models

2015 ◽  
Vol 22 (6) ◽  
pp. 639-646 ◽  
Author(s):  
António Completo ◽  
Abel Nascimento ◽  
António Ramos ◽  
José Simões
Keyword(s):  
Finite Element ◽  
Vertebral Body ◽  
Body Height ◽  
Total Disc Replacement ◽  
Disc Replacement ◽  
Vertebral Body Height ◽  
Single Level ◽  
Cervical Segment ◽  
Multiple Levels ◽  
Fusion Cage

OBJECT The purpose of this study was to evaluate the failure risk of cervical vertebrae after total disc replacement with a keel-design prosthesis (ProDisc-C), taking into consideration the effects of vertebral body height, multilevel replacement, and the association with an adjacent fusion cage. Although promising clinical results have been reported for the ProDisc-C, some clinical studies have reported vertebral body–splitting fractures at single- and multilevel arthroplasty sites. This implant has central keels to provide solid initial stability, and some authors associate the potential risk of vertebral body failure with the keel design, especially in patients with small vertebral body height or when the implant is used at multiple levels. METHODS The study was performed using a specimen-specific C4–6 cervical-segment finite-element model to assess the compressive strains on the C-5 vertebral body for each cervical segment configuration, and synthetic polyurethane models to experimentally predict the compressive load at failure for 3 vertebral body heights. RESULTS The use of a keeled ProDisc-C prosthesis at multiple levels or in combination with a fusion cage increases by a factor of 2–3 the compressive strains at the C-5 vertebral body relative to single-level arthroplasty. All implanted segment configurations tested demonstrated a continuum of the load at failure and the vertebral body height, but no significant differences were found between the 3 vertebral body heights in each segment configuration. CONCLUSIONS The use of a keeled ProDisc-C prosthesis at 2 adjacent levels or combined with a fusion cage presented the lowest load-at-failure values, 2 times higher on average than the ones occurring during physiological tasks. This fact indicates an identical and limited risk of vertebral body failure for these 2 segment configurations, whereas vertebral body height appears to slightly affect this risk. However, for some tasks that place higher physical demands on the neck, beyond what was represented by our models, there may also be risk of microdamage initiation, which is not present in the single-level arthroplasty.

Segmental Motion of the Cervical Spine After Total Disc Replacement Using ActivC Versus Discectomy and Fusion Using Stand-alone Cage

2019 ◽  
Vol 126 ◽  
pp. e1228-e1234 ◽  
Author(s):  
Bum-Joon Kim ◽  
Se-Hoon Kim ◽  
Seung-Hwan Lee ◽  
Sung-Kon Ha ◽  
Sang-Dae Kim ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Total Disc Replacement ◽  
Disc Replacement ◽  
Segmental Motion

BIOMECHANICS OF CERVICAL SPINE FOLLOWING IMPLANTATION OF A SEMI-CONSTRAINED ARTIFICIAL DISC WITH UPWARD CENTER OF ROTATION: A FINITE ELEMENT INVESTIGATION

2015 ◽  
Vol 15 (04) ◽  
pp. 1550063 ◽  
Author(s):  
D. AKBARIAN ◽  
G. ROUHI ◽  
M. MOSAVI MASHHADI ◽  
W. HERZOG
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Total Disc Replacement ◽  
Intradiscal Pressure ◽  
Fe Model ◽  
Facet Joints ◽  
Artificial Disc ◽  
Test Protocol ◽  
Center Of Rotation ◽  
Flexion Extension

The objective of this study was to evaluate the effects of a semi-constrained artificial disc with upward instantaneous center of rotation (ICR) on the biomechanics of the cervical spine. A three-dimensional nonlinear finite element model of the lower cervical spine (C4–C7) was developed using computed tomography (CT) data. The FE model was validated by comparing it to previously published experimental results for flexion-extension, lateral bending and axial rotation movements. The validated model was then altered to include prosthesis at the C5–C6 level. A hybrid test protocol was used to investigate the effects of total disc replacement. The results of this study showed that this artificial disc can help maintain the same range of motion (ROM) and intradiscal pressure as the intact model for most loading conditions. We also found that loads on the facet joints increased dramatically at index level. The capsular ligaments were also found to transmit more tension during flexion at implanted level. Although the artificial disc with upward ICR was found to restore normal kinematics, and prevented increases in intradiscal pressure, it was also associated with an overloading of the facet joints and capsular ligaments leading to potentially undesirable outcomes in the long term.

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