Modeling of Facet Articulation as a Nonlinear Moving Contact Problem: Sensitivity Study on Lumbar Facet Response

1998 ◽  
Vol 120 (1) ◽  
pp. 118-125 ◽  
Author(s):  
M. Sharma ◽  
N. A. Langrana ◽  
J. Rodriguez
Keyword(s):  
Contact Problem ◽  
Spatial Orientation ◽  
Facet Joint ◽  
Sensitivity Study ◽  
Geometric Parameters ◽  
Load Transmission ◽  
Moving Contact ◽  
Articular Surfaces ◽  
Motion Segment ◽  
Flexion Extension

A finite element (FE) based scheme for modeling facet articulation in a spinal motion segment is proposed. The algorithm presented models the facet articulation as a nonlinear progressive contact problem. This algorithm is used to perform a nonlinear FE analysis of a complete L3-L4 motion segment. The role of facets in load transmission through a motion segment and its sensitivity to facet geometric parameters (i.e., spatial orientation of the facets and the gap between the facet articular surfaces) on this load transmission are studied. Compression, flexion, extension, and torsion loads are used in this study. The effect of facetectomy on gross segment response and disk fiber strains is studied by comparing the response of FE models of motion segment with and without facets. Large facet loads are obtained when the motion segment is subjected to torsional and large extension rotations, whereas minimal facet loads are observed under compression and flexion loading. Removal of facets reduces the segment stiffness considerably in torsion and results in higher strain levels in disk fibers. The facet load transmission is sensitive to facet geometric parameters, i.e., spatial orientation and initial facet joint gap. The facet loads increase uniformly with decrease in initial gap between the facet articular surfaces under compression, extension, and torsional loads. The sensitivity to spatial orientation angles of the facet is, however, found to vary with the type of loading. This sensitivity may account for the wide variation in the facet response reported in literature.

scholarly journals The biomechanical effect on the adjacent L4/L5 segment of S1 superior facet arthroplasty: a finite element analysis for the male spine

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Zewen Shi ◽  
Lin Shi ◽  
Xianjun Chen ◽  
Jiangtao Liu ◽  
Haihao Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Range Of Motion ◽  
Facet Joint ◽  
Adjacent Segment ◽  
Finite Element Models ◽  
Level Of Evidence ◽  
Element Analysis ◽  
Flexion Extension ◽  
Biomechanical Effect ◽  
Lumbar Range Of Motion

Abstract Background The superior facet arthroplasty is important for intervertebral foramen microscopy. To our knowledge, there is no study about the postoperative biomechanics of adjacent L4/L5 segments after different methods of S1 superior facet arthroplasty. To evaluate the effect of S1 superior facet arthroplasty on lumbar range of motion and disc stress of adjacent segment (L4/L5) under the intervertebral foraminoplasty. Methods Eight finite element models (FEMs) of lumbosacral vertebrae (L4/S) had been established and validated. The S1 superior facet arthroplasty was simulated with different methods. Then, the models were imported into Nastran software after optimization; 500 N preload was imposed on the L4 superior endplate, and 10 N⋅m was given to simulate flexion, extension, lateral flexion and rotation. The range of motion (ROM) and intervertebral disc stress of the L4-L5 spine were recorded. Results The ROM and disc stress of L4/L5 increased with the increasing of the proportions of S1 superior facet arthroplasty. Compared with the normal model, the ROM of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 2/5 from the apex to the base. The disc stress of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 1/5 from the apex to the base. Conclusion In this study, the ROM and disc stress of L4/L5 were affected by the unilateral S1 superior facet arthroplasty. It is suggested that the forming range from the ventral to the dorsal should be less than 3/5 of the S1 upper facet joint. It is not recommended to form from apex to base. Level of evidence Level IV

An Interlocking Ligamentous Spinal Disk Arthroplasty with Neural Network Infrastructure

2010 ◽  
Vol 7 ◽  
pp. 55-79 ◽  
Author(s):  
Philip Boughton ◽  
James Merhebi ◽  
C. Kim ◽  
G. Roger ◽  
Ashish D. Diwan ◽  
...  
Keyword(s):  
Neural Network ◽  
Finite Element ◽  
Axial Compression ◽  
Wire Array ◽  
Axial Strain ◽  
Compressive Strain ◽  
Niti Wire ◽  
Motion Segment ◽  
Flexion Extension

An elastomeric spinal disk prosthesis design (BioFI™) with vertebral interlocking anchors has been modified using an embedded TiNi wire array. Bioinert styrenic block copolymer (Kraton®) and polycarbonate urethane (Bionate®) thermoplastic elastomer (TPE) matrices were utilized. Fatigue resistant NiTi wire was pretreated to induce superelastic martensitic microstructure. Stent-like helical structures were produced for incorporation within homogenous TPE matrix. Composite prototypes were fabricated in a vacuum hot press using transfer moulding techniques. Implant prototypes were subject to axial compression using a BOSE ® ELF3400. The NiTi reinforced implants exhibited reduction in axial strain, compliance, and creep compared to TPE controls. The axial properties of the NiTi reinforced Bionate® BioFI™ implant best approximated those of a spinal disk followed by Kraton®-NiTi, Bionate® and Kraton® prototypes. An ovine lumbar segment biomechanical model was used to characterize the disk prosthesis prototypes. Specimens were subject to 7.5Nm pure moments in axial rotation, flexion-extension and lateral bending with a custom jig mounted on an Instron® 8874. The motion preserving ligamentous nature of this arthroplasty prototype was not inhibited by NiTi reinforcement. Joint stiffness for all prototypes was significantly less than the intact and discectomy controls. This was due to lack of vertebral anchor rigidity rather than BioFI™ motion segment matrix type or reinforcement. Implant stress profiles for axial compression and axial torsion conditions were obtained using finite element methods. The biomechanical testing and finite element modelling both support existing BioFI™ design specifications for higher modulus vertebral anchors, endplates and motion segment periphery with gradation to a low modulus core within the motion segment. This closer approximation of the native spinal disk form translates to improvements in prosthesis biomechanical fidelity and longevity. Axial compressive strain induced within a TiNi reinforced Kraton® BioFI™ was found to be linearly proportional to the NiTi helical coil electrical resistance. This neural network capability delivers opportunities to monitor and telemeterize in situ multiaxis joint structural performance and in vivo spine biomechanics.

scholarly journals Multiscale modelling of the human lumbar facet capsular ligament: analysing spinal motion from the joint to the neurons

2018 ◽  
Vol 15 (148) ◽  
pp. 20180550
Author(s):  
Vahhab Zarei ◽  
Rohit Y. Dhume ◽  
Arin M. Ellingson ◽  
Victor H. Barocas
Keyword(s):  
Axial Rotation ◽  
Fe Model ◽  
Spinal Motion ◽  
Capsular Ligament ◽  
Segment Model ◽  
Motion Segment ◽  
Flexion Extension ◽  
Vertebral Kinematics ◽  
High Level ◽  
Lumbar Facet

Due to its high level of innervation, the lumbar facet capsular ligament (FCL) is suspected to play a role in low back pain (LBP). The nociceptors in the lumbar FCL may experience excessive deformation and generate pain signals. As such, understanding the mechanical behaviour of the FCL, as well as that of its underlying nerves, is critical if one hopes to understand its role in LBP. In this work, we constructed a multiscale structure-based finite-element (FE) model of a lumbar FCL on a spinal motion segment undergoing physiological motions of flexion, extension, ipsilateral and contralateral bending, and ipsilateral axial rotation. Our FE model was created for a generic FCL geometry by morphing a previously imaged FCL anatomy onto an existing generic motion segment model. The fibre organization of the FCL in our models was subject-specific based on previous analysis of six dissected specimens. The fibre structures from those specimens were mapped onto the FCL geometry on the motion segment. A motion segment model was used to determine vertebral kinematics under specified spinal loading conditions, providing boundary conditions for the FCL-only multiscale FE model. The solution of the FE model then provided detailed stress and strain fields within the tissue. Lastly, we used this computed strain field and our previous studies of deformation of nerves embedded in fibrous networks during simple deformations (e.g. uniaxial stretch, shear) to estimate the nerve deformation based on the local tissue strain and fibre alignment. Our results show that extension and ipsilateral bending result in largest strains of the lumbar FCL, while contralateral bending and flexion experience lowest strain values. Similar to strain trends, we calculated that the stretch of the microtubules of the nerves, as well as the forces exerted on the nerves' membrane are maximal for extension and ipsilateral bending, but the location within the FCL of peak microtubule stretch differed from that of peak membrane force.

Cervical motion segment contributions to head motion during flexion\extension, lateral bending, and axial rotation

2015 ◽  
Vol 15 (12) ◽  
pp. 2538-2543 ◽  
Author(s):  
William J. Anderst ◽  
William F. Donaldson ◽  
Joon Y. Lee ◽  
James D. Kang
Keyword(s):  
Axial Rotation ◽  
Head Motion ◽  
Lateral Bending ◽  
Motion Segment ◽  
Flexion Extension ◽  
Cervical Motion

A Novel In Vivo Measurement of Three-Dimensional Lumbar Facet Joint Orientation and Area

2007 ◽  
Author(s):  
Yoshihisa Otsuka ◽  
Howard S. An ◽  
Jamie R. Williams ◽  
Ruth S. Ochia ◽  
Kazuyoshi Yamaguchi ◽  
...  
Keyword(s):  
Facet Joint ◽  
Three Dimensional ◽  
Joint Surface ◽  
Lumbar Facet Joint ◽  
Joint Orientation ◽  
In Vivo Measurement ◽  
Load Transmission ◽  
Facet Orientation ◽  
Lumbar Facet

Changes in load transmission through facet and facet orientation have been considered as an important factor in intervertebral disc degeneration and osteoarthritic changes of the facet joint. (1)(2)(3) Facet joint surface area and orientation of the facets play key roles in load transmission. Their information is important for designing implants of the spine. They have been 2-dimentionally measured using CT and MRI. (4)(5) The purpose of the current study was to establish a three-dimensional (3D) technique for measuring lumbar facet joint area and orientation in vivo.

THE EFFECT OF ARTICULAR SURFACE SHAPE AND TENDON FORCES OF TOTAL WRIST ARTHROPLASTY SYSTEMS: A FINITE ELEMENT STUDY

2012 ◽  
Vol 15 (04) ◽  
pp. 1250021 ◽  
Author(s):  
Matthew B. A. McCullough ◽  
Brian D. Adams ◽  
Nicole M. Grosland
Keyword(s):  
Finite Element ◽  
Articular Surface ◽  
Surface Shape ◽  
Element Analysis ◽  
Future Directions ◽  
Ulnar Deviation ◽  
Articular Surfaces ◽  
Total Wrist Arthroplasty ◽  
Flexion Extension ◽  
Wrist Arthroplasty

In order to better understand the behavior of the total wrist implant systems, finite element analysis (FEA) was used to model the articular surfaces of two unconstrained total wrist arthroplasty (TWA) devices. After creating models based on manufacturer specifications, simulations of flexion, extension, radial deviation, ulnar deviation and circumduction were run with simulated moments from surrounding tendons under displacement control. In addition, simulations were run under positioning that represented a pronated and supinated forearm as well as unstable conditions. Understanding implant behavior and capabilities as related to the shape of the articular surfaces is important for proper prescription of implants as well as determining future directions for the design of arthroplasty devices.

DETERMINATION OF LOAD TRANSMISSION AND CONTACT FORCE AT FACET JOINTS OF L2–L3 MOTION SEGMENT USING FE METHOD

2003 ◽  
Vol 07 (02) ◽  
pp. 97-109 ◽  
Author(s):  
E. C. Teo ◽  
K. K. Lee ◽  
H. W. Ng ◽  
T. X. Qiu ◽  
K. Yang
Keyword(s):  
Axial Compression ◽  
Contact Force ◽  
Fe Model ◽  
Percentage Increase ◽  
Facet Joints ◽  
Fe Method ◽  
Load Transmission ◽  
Motion Segment

In the human spine, it is well known that facet joints play a significant role in load transmission and providing stability. It has also been hypothesized to be one of most probable sources of low back pain. Experimental determination of the load-bearing role of lumbar intervertebral joints, such as the facets joints, under axial compression has not been a straightforward task. In this study, the role of the facets in load transmission through a L2–L3 motion segment under axial compression is investigated using a L2–L3 finite element (FE) model, incorporated with an accurate three-dimensional geometry of facet joints with the inclusion of surface-to-surface continuum contact representation. The effects of osteoarthritis on facet force and biomechanical behaviors are also investigated by assuming friction at the facet joints. The study shows that the facet joints resisted 8% more in load for joints with osteoarthritics as compared with the normal joints. High percentage increase in contact facet force was also predicted for joint with osteoarthritics deformity. The use of the analytical FE model provided yet another efficient alternative for predicting the load transmission and contact force for degenerative joints, so as to provide a better understanding of the biomechanics of the spine as well as the pathophysiology of the various spinal disorders and degenerative conditions.

Autologous Human Fibrochondrocytes From Meniscectomy Debris are a Potent Cell Source for Meniscus Tissue Engineering

2007 ◽  
Author(s):  
Brendon M. Baker ◽  
Ashwin S. Nathan ◽  
Neil P. Sheth ◽  
G. Russell Huffman ◽  
Robert L. Mauck
Keyword(s):  
Tissue Engineering ◽  
Extracellular Matrix ◽  
Normal Functioning ◽  
Arthroscopic Partial Meniscectomy ◽  
Load Transmission ◽  
Articular Surfaces ◽  
Meniscus Tissue ◽  
Cell Source ◽  
Inner Region ◽  
Collagenous Structure

The meniscus is a fibrocartilaginous tissue vital to the normal functioning of the knee [1]. The dense collagenous structure is sparsely colonized by meniscal fibrochondrocytes (MFCs) which maintain and remodel the extracellular matrix (ECM) [2,3]. While the meniscus functions well with a lifetime of use, traumatic or degenerative injuries to the avascular, inner region of the meniscus fail to heal. Disruption of the fibrous architecture impairs load transmission and initiates erosion of the adjacent articular surfaces, or osteoarthritis (OA). Damage to the meniscus is typically treated by resection of the torn tissue via arthroscopic partial meniscectomy, which alleviates symptoms but similarly predisposes patients to OA [4]. Tissue removed in this procedure is deemed surgical waste and is subsequently discarded.

Biomechanical Comparison of Contact Pressure in the Cervical Facet Joint During Bending Using a Probe and Pressure-Sensitive Paper

2010 ◽  
Author(s):  
Nicolas V. Jaumard ◽  
Joel A. Bauman ◽  
William C. Welch ◽  
Beth A. Winkelstein
Keyword(s):  
Contact Pressure ◽  
Facet Joint ◽  
Articular Surface ◽  
Joint Mechanics ◽  
Pressure Sensitive ◽  
Articular Surfaces ◽  
Facet Joint Pain ◽  
Biomechanical Comparison ◽  
Cervical Facet ◽  
Cervical Facet Joint

Non-physiologic loading of the facet joint is a potential cause of facet joint pain in the cervical spine [1]. When the local biomechanical environment of the facet joint is altered, like with trauma or after surgery [2], the cartilaginous articular surfaces of the facets can also be damaged. Defining articular contact pressure can provide a metric of altered joint mechanics and the local mechanical environment of the cartilage in the facet joint. However, accessing the articular surface to make such measurements without altering the overall mechanics of the joint remains a substantial challenge.

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