A finite element study of a lumbar motion segment subjected to pure sagittal plane moments

Shirazi‐Adl, A.; Ahmed, A. M.; Shrivastava, S.C.

doi:10.1016/0021-9290(86)90009-6

Cited by 240 publications

(139 citation statements)

References 51 publications

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“…A recently published review of the literature clearly pointed out that in animal models at least disc degeneration can be provoked by inappropriate mechanical signals [16,19]. Multiple mechanical factors affect the IVD in vivo [1,14], as this structure has to provide flexibility, stabilization and shock absorbance in its function as the joint of the spine. Although, mechanical loading appears to influence tissue turnover, there is currently little information on how the load intensities affect cellular responses.…”

Section: Introductionmentioning

confidence: 99%

Regulation of gene expression in intervertebral disc cells by low and high hydrostatic pressure

et al. 2006

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Intervertebral disc structures are exposed to wide ranges of intradiscal hydrostatic pressure during different loading excercises and are at their minimum during lying or relaxed sitting and at maximum during lifting weights with a round back. We hypothesize that these different loading magnitudes influence the intervertebral disc (IVD) by alteration of disc matrix turnover depending on their magnitudes. Therefore the aim of this study was to assess changes in gene expression of human nucleus cells after the application of low hydrostatic pressure (0.25 MPa) and high hydrostatic pressure (2.5 MPa). IVD cells isolated from the nucleus of human (n = 18) and bovine (n = 24 from four animals) disc biopsies were seeded into three-dimensional collagen type-I matrices and exposed to the different loading magnitudes by specially developed pressure chambers. The lower pressure range (0.25 MPa, 30 min, 0.1 Hz) was applied with a recently published device by using an external compression cylinder. For the application of higher loads (2.5 MPa, 30 min, 0.1 Hz) the cell-loaded collagen gels were sealed into sterile bags with culture medium and stimulated in a newly developed water-filled compression cylinder by using a loading frame. These methods allowed the comparison of loading regimes in a wide physiological range under an equal three-dimensional culture conditions. Cells were harvested 24 h after the end of stimulation and changes in the expression of genes known to influence IVD matrix turnover (collagen-I, collagen-II, aggrecan, MMP1, MMP2, MMP3, MMP13) were analyzed by real-time RT-PCR. A Wilcoxon signed-rank test 1 and a Wilcoxon 2-sample test 2 were performed to detect differences between the stimulated and control samples 1 and differences between low and high hydrostatic pressure 2 . Multiple testing was considered by adjusting the p value appropriately. Both regimes of hydrostatic pressure influenced gene expression in nucleus cells with opposite tendencies for the matrix forming proteins aggrecan and collagen type-I in response to the two different pressure magnitudes: Low hydrostatic-pressure (0.25 MPa) tended to increase collagen-I and aggrecan expression of human nucleus cells (P < 0.05) but only to a small degree. High hydrostatic pressure (2.5 MPa) tended to decrease gene expression of all anabolic proteins with significant effects on aggrecan expression of nucleus cells (P = 0.004). Low hydrostatic pressure had no influence on the expression of matrix metalloproteinases (MMP1, MMP2, MMP3 and MMP13). In contrast, high hydrostatic pressure tended to increase the expression of MMP1, MMP3 and MMP13 of human nucleus cells with high individualindividual variations. The decreased expression of aggrecan (P = 0.008) and collagen type II (P = 0.023) and the increased MMP3 expression (P = 0.008) in response to high hydrostatic pressure could be confirmed in additional experiments with bovine nucleus cells. These results suggest that hydrostatic pressure as one of the physiological stimuli of the IVD may inf...

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Section: Introductionmentioning

confidence: 99%

Regulation of gene expression in intervertebral disc cells by low and high hydrostatic pressure

et al. 2006

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“…Most geometrical and dynamic physics modelling of lumbar spine in the literature are carried out using Finite Element Modelling (FEM). One of the earliest techniques that uses FEM is detailed in [22] and [35]. A more recent technique to create 3D geometrical and mechanical model of lumbar spine with FEM is proposed by Nabhani and Wake [36] which modelled the L4 and L5 vertebrae.…”

Section: Three-dimensional Geometrical and Physics Modelling Of Lumbamentioning

confidence: 99%

“…Physics engine libraries are traditionally used to develop gaming, robotics, or flight simulations but more recently they are used by researchers for medical purposes [19]. Furthermore, our initial review of the literature reveals that there are some progress in the modelling of the lumbar spine as a 3D computer model as well as mathematical/physics model [20]- [22]. It is believed that these advances in physics modelling coupled with computer technologies can help solve the problem of future prediction of CLBP.…”

Section: Introductionmentioning

confidence: 99%

A Framework on a Computer Assisted and Systematic Methodology for Detection of Chronic Lower Back Pain Using Artificial Intelligence and Computer Graphics Technologies

Kafri

Sudirman

Hussain

et al. 2016

Intelligent Computing Theories and Application

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Abstract. Back pain is one of the major musculoskeletal pain problems that can affect many people and is considered as one of the main causes of disability all over the world. Lower back pain, which is the most common type of back pain, is estimated to affect at least 60% to 80% of the adult population in the United Kingdom at some time in their lives. Some of those patients develop a more serious condition namely Chronic Lower Back Pain in which physicians must carry out a more involved diagnostic procedure to determine its cause. In most cases, this procedure involves a long and laborious task by the physicians to visually identify abnormalities from the patient's Magnetic Resonance Images. Limited technological advances have been made in the past decades to support this process. This paper presents a comprehensive literature review on these technological advances and presents a framework of a methodology for diagnosing and predicting Chronic Lower Back Pain. This framework will combine current state-of-the-art computing technologies including those in the area of artificial intelligence, physics modelling, and computer graphics, and is argued to be able to improve the diagnosis process.

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“…The shape of a lumbar segment was reconstructed from data obtained after computed tomography scans of a human L3/4 segment as detailed anatomy, and interpreted as anisotropic finite element model, based on the work done by Goel et al [ 9,10] and Shirazi-Adl et al [17]. The thickness of the endplates and cortical shell were set to 0.25 and 0.4 mm respectively [18].…”

Section: Biomechanical Studymentioning

confidence: 99%

“…The nucleus pulposus was specified as an incompressible structure [10]. The two facet joints were simulated as gap elements, with all essential ligaments added to the bony structures, using material properties from the literature [9,10,14,17,19]. The finite element model of the intact L3/4 motion segment consisted of 7433 single elements.…”

Section: Biomechanical Studymentioning

confidence: 99%

Motion of threaded cages in posterior lumbar interbody fusion

Pitzen¹,

Geisler

Matthis

et al. 2000

European Spine Journal

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IntroductionPosterior lumbar interbody fusion (PLIF) was first described by Briggs and Milligan in 1944 [4] and modified by Cloward in 1953 [6]. PLIF is a surgically sophisticated technique for arthrodesis and stabilisation within the intradiscal space of an unstable lumbar segment. It consists of a generous posterior decompression of the neural structures and then a discectomy and anterior interbody arthrodesis. The intradiscal work is performed between the exiting nerve root and the retracted transversal nerve root and thecal sac at the lumbar motion segment to be stabilised. Indications for this procedure include degenerative lumbar instability and spondylolisthesis [6,11,12,15]. This surgical approach has the advantage over posterior arthrodesis of obtaining a mature fusion in the anterior column, which bears 80% of the axial load and is under compression in an upright posture [20]. Cloward's technique [6] consisted of interbody fusion using autologous iliac crest bone grafts without additional internal stabilisation. The major disadvantage of this technique is the minimal initial internal stabilisation. Furthermore, the stiffness of these constructs decreases in the first few months during the graft absorption and initial integration phase. Graft-related complications with this technique have been reported to range from 3 to 18% [5,16,22]. To improve these initial results with PLIF operations, a variAbstract A high rate of pseudarthrosis and a high overall rate of implant migration requiring surgical revision has been reported following posterior lumbar interbody fusion using BAK threaded cages. The high rate of both pseudarthrosis and implant migration may be due to poor fixation of the implant. The purpose of this study was to analyse the motion of threaded cages in posterior lumbar interbody fusion. Six cadaveric human lumbar spine segments (three L2/3 and three L4/5 segments) were prepared for biomechanical testing. The segments were tested, without preload, under forces of axial compression (600 N), torsion (25 Nm) and shearing force (250 N).The tests were performed first with the segments in an intact state, and subsequently following instrumented stabilisation with two BAK cages via a posterior approach. These results were compared with those of a finite element model simulating the effects of identical forces on the segments with constructs. As the results were comparable, the finite element model was used for analysing the motion of BAK cages within the disc space. Motion of the implants was not seen in compression. In torsion, a rolling motion was noted, with a range of motion of 10.6°around the central axis of the implant when left/right torsion (25 Nm) was applied. The way the implants move within the segment may be due to their special shape: the thread of the implants can not prevent the BAK cages rolling within the disc space.

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A finite element study of a lumbar motion segment subjected to pure sagittal plane moments

Cited by 240 publications

References 51 publications

Regulation of gene expression in intervertebral disc cells by low and high hydrostatic pressure

Regulation of gene expression in intervertebral disc cells by low and high hydrostatic pressure

A Framework on a Computer Assisted and Systematic Methodology for Detection of Chronic Lower Back Pain Using Artificial Intelligence and Computer Graphics Technologies

Motion of threaded cages in posterior lumbar interbody fusion

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