scholarly journals Convergence analysis and validation of a discrete element model of the human lumbar spine

2022 ◽  
Vol 3 (1) ◽  
pp. 62-70
Author(s):  
Galina Eremina ◽  
◽  
Alexey Smolin ◽  
Irina Martyshina ◽  
◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Bone Tissue ◽  
Vertebral Body ◽  
Loading Rate ◽  
Numerical Models ◽  
Fold Increase ◽  
Intervertebral Discs ◽  
Effective Stiffness ◽  
Structural Element

Degenerative diseases of the spine can lead to or hasten the onset of additional spinal problems that significantly reduce human mobility. The spine consists of vertebral bodies and intervertebral discs. The most degraded are intervertebral discs. The vertebral body consists of a shell (cortical bone tissue) and an internal content (cancellous bone tissue). The intervertebral disc is a complex structural element of the spine, consisting of the nucleus pulposus, annulus fibrosus, and cartilaginous plates. To develop numerical models for the vertebral body and intervertebral disc, first, it is necessary to verify and validate the models for the constituent elements of the lumbar spine. This paper, for the first time, presents discrete elements-based numerical models for the constituent parts of the lumbar spine, and their verification and validation. The models are validated using uniaxial compression experiments available in the literature. The model predictions are in good qualitative and quantitative agreement with the data of those experiments. The loading rate sensitivity analysis revealed that fluid-saturated porous materials are highly sensitive to loading rate: a 1000-fold increase in rate leads to the increase in effective stiffness of 130 % for the intervertebral disc, and a 250-fold increase in rate leads to the increase in effective stiffness of 50 % for the vertebral body. The developed model components can be used to create an L4-L5 segment model, which, in the future, will allow investigating the mechanical behavior of the spine under different types of loading.

scholarly journals Retroperitoneal oblique corridor to the L2–S1 intervertebral discs: an MRI study

2016 ◽  
Vol 24 (2) ◽  
pp. 248-255 ◽  
Author(s):  
Diana M. Molinares ◽  
Timothy T. Davis ◽  
Daniel A. Fung
Keyword(s):  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Vertebral Body ◽  
Psoas Muscle ◽  
Intervertebral Discs ◽  
Mr Images ◽  
Disc Space ◽  
Iliac Vessel ◽  
Medial Border ◽  
Transpsoas Approach

OBJECT The purpose of this study was to analyze MR images of the lumbar spine and document: 1) the oblique corridor at each lumbar disc level between the psoas muscle and the great vessels, and 2) oblique access to the L5–S1 disc space. Access to the lumbar spine without disruption of the psoas muscle could translate into decreased frequency of postoperative neurological complications observed after a transpsoas approach. The authors investigated the retroperitoneal oblique corridor of L2–S1 as a means of surgical access to the intervertebral discs. This oblique approach avoids the psoas muscle and is a safe and potentially superior alternative to the lateral transpsoas approach used by many surgeons. METHODS One hundred thirty-three MRI studies performed between May 4, 2012, and February 27, 2013, were randomly selected from the authors’ database. Thirty-three MR images were excluded due to technical issues or altered lumbar anatomy due to previous spine surgery. The oblique corridor was defined as the distance between the left lateral border of the aorta (or iliac artery) and the anterior medial border of the psoas. The L5–S1 oblique corridor was defined transversely from the midsagittal line of the inferior endplate of L-5 to the medial border of the left common iliac vessel (axial view) and vertically to the first vascular structure that crossed midline (sagittal view). RESULTS The oblique corridor measurements to the L2–5 discs have the following mean distances: L2–3 = 16.04 mm, L3–4 = 14.21 mm, and L4–5 = 10.28 mm. The L5–S1 corridor mean distance was 10 mm between midline and left common iliac vessel, and 10.13 mm from the first midline vessel to the inferior endplate of L-5. The bifurcation of the aorta and confluence of the vena cava were also analyzed in this study. The aortic bifurcation was found at the L-3 vertebral body in 2% of the MR images, at the L3–4 disc in 5%, at the L-4 vertebral body in 43%, at the L4–5 disc in 11%, and at the L-5 vertebral body in 9%. The confluence of the iliac veins was found at lower levels: 45% at the L-4 level, 19.39% at the L4–5 intervertebral disc, and 34% at the L-5 vertebral body. CONCLUSIONS An oblique corridor of access to the L2–5 discs was found in 90% of the MR images (99% access to L2–3, 100% access to L3–4, and 91% access to L4–5). Access to the L5–S1 disc was also established in 69% of the MR images analyzed. The lower the confluence of iliac veins, the less probable it was that access to the L5–S1 intervertebral disc space was observed. These findings support the use of lumbar MRI as a tool to predetermine the presence of an oblique corridor for access to the L2–S1 intervertebral disc spaces prior to lumbar spine surgery.

scholarly journals RESEARCH ON THE INFLUENCE OF THE PROPERTIES OF INTERVERTEBRAL DISC STIFFNESS OF THE LUMBAR SPINE ON THE DISPLACEMENT OF VERETBRAE / STUBURO JUOSMENINĖS DALIES TARPSLANKSTELINIO DISKO STANDUMO CHARAKTERISTIKŲ ĮTAKOS SLANKSTELIŲ POSLINKIAMS TYRIMAS

2015 ◽  
Vol 6 (6) ◽  
pp. 595-597
Author(s):  
Artūras Linkel ◽  
Julius Griškevičius ◽  
Gintaras Jonaitis
Keyword(s):  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Degrees Of Freedom ◽  
Angular Displacement ◽  
Fast Response ◽  
Intervertebral Discs ◽  
Linear Displacement ◽  
Basic Task ◽  
Non Linear ◽  
Solid Bodies

The article proposes the method for evaluating angular and linear changes in intervertebral discs of the spine depending on linear and nonlinear intervertebral disc stiffness. A dynamic made of 5 solid bodies connected by damping and stiffness components and applied for 2-D 10 degrees of freedom of the lumbar spine has been used for calculations. The system of the equation has been written in a matrix form. Lumbar intervertebral discs stiffness and damping properties have been selected from scientific articles and make from 200 N/mm to 1200 N/mm and from 229 Ns / mm to 5100 Ns/mm respectively for non-linear calculation and 800 N / mm – 2637 Ns/mm for linear displacement calculation. External loads applied to the model are 1648 N, 2957 N, 3863 N and 4542 N. The basic task of the paper is to calculate the biggest difference in linear and angular displacement considering 2 cases: linear and non-linear stiffness value. The greatest estimated difference, under the highest load, makes 0.6 mm for linear and 0.95 degrees for angular displacement. Because of the fast response of the model to the load, the damping value could not affect displacement. Tyrimo objektas yra stuburo trapslankstelinių diskų poslinkių skirtumai esant tiesiniam ir netiesiniam jų standumo koeficientui. Taikomas 10 laisvės laipsnių 2-D stuburo juosmeninės dalies dinaminis modelis, kuris susideda iš 5 juosmens slankstelių, sujungtų standumo ir slopinimo ryšiais. Modeliui nustatomos juosmens apkrovos, kurios susidaro važiuojant dviračiu. Tarpslankstelinių diskų savybės parenkamos iš mokslinės literatūros. Sudarytas matematinis modelis leido apskaičiuoti stuburo slankstelių linijinius ir kampinius poslinkius įvertinant tarpslankstelinio disko standžio netiesiškumą. Atlikti skaičiavimai parodė, kad didžiausi skirtumai susidaro esant maksimaliai apkrovai. Didžiausi linijinių poslinkių skirtumai yra 0,6 mm, o kampinių – 0,95 laipsnio. Nustatytos slopinimo koeficiento reikšmės dėl greito modelio atsako poslinkių skaičiavimams įtakos neturėjo.

scholarly journals Is age more than manual material handling associated with lumbar vertebral body and disc changes? A cross-sectional multicentre MRI study

BMJ Open ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. e029657
Author(s):  
Francesco S Violante ◽  
Maurizio Zompatori ◽  
Piero Lovreglio ◽  
Pietro Apostoli ◽  
Francesco Marinelli ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Vertebral Body ◽  
Material Handling ◽  
Musculoskeletal Diseases ◽  
Lumbar Disc ◽  
Secondary Outcome ◽  
Cross Sectional ◽  
Manual Material Handling ◽  
Lumbar Vertebral Body

ObjectiveConflicting evidence exists to what extent manual material handling (MMH) causes lumbar disc disease, lack of evidence exist that this effect takes place especially at L5-S1 level, where the greatest moment occurs. The aim was to assess if lumbar vertebral body and disc changes are more common in people whose job involves significant MMH and, if so, to evaluate if lumbar vertebral body and disc changes are more prevalent in the lower part of the lumbar spine (L4-L5 and L5-S1).DesignObservational, cross-sectional, with quasi-random recruitment.SettingOutpatient radiology units of three large hospitals in northern (Bologna and Brescia) and southern (Bari) Italy.Participants183 consecutive adult subjects (89 males, 94 females) aged 20–70 years referred by the general practitioner or a specialist for MRI of the lumbar spine.Primary and secondary outcome measuresNeuroradiologists (blind to clinical assessment) evaluated the prevalence of intervertebral disc and vertebral body changes in standardised MRI examinations. History of personal and family musculoskeletal diseases and injuries, current and previous MMH at work and during leisure time were assessed by interview and self-administered questionnaire.ResultsParticipants were classified according their occupational exposure to MMH. No association was found between MMH and vertebral body and intervertebral disc changes, whereas age over 45 years was consistently associated with more disc extension beyond the interspace changes, Pfirrmann changes, osteophytes and Modic changes: the association was statistically significant at the conventional 5% level.ConclusionsAge, and not MMH, seems to primarily affect the presence of intervertebral disc changes; prospective studies are needed to better explore the relationship between MMH and the possible presence (and level) of lumbar vertebral body and/or disc changes.

Assessment of the Dynamic Response of a Lumbar Spine Functional Unit Under Axial Compressive High Loading Rate: Outcome on the Axial Disc Bulge and its Relation to the Load Magnitude

2013 ◽  
Author(s):  
Chandrashekhar K. Thorbole ◽  
M. Jorgensen ◽  
H. M. Lankarani
Keyword(s):  
Lumbar Spine ◽  
Dynamic Response ◽  
Vertebral Body ◽  
Dynamic Load ◽  
Loading Rate ◽  
High Loading ◽  
Fe Model ◽  
End Plate ◽  
Functional Spinal Unit ◽  
High Loading Rate

Human lumbar spine tolerance to the compressive impact loading is less when compared to its tolerance to the perpendicular dynamic load. The dynamic response of the functional spinal unit in compressive loading is governed by the viscoelastic behavior of the IVD (Intervertebral disc). The axial bulge of the disc is the result of viscoelastic nature of the nucleus which tends to swell under high loading rate. This characteristic causes the end-plate to bow into the cancellous bone as it is supported by the strong cortical bone on its periphery. The end-plate is one of the important elements in the functional spinal unit if failed results disc material to progress into the vertebral body beneath it. This paper quantifies the axial bulge of the end-plate under dynamic compressive load using Finite Element Method. A simple validated axis symmetry FE model is employed to identify the most vulnerable lumbar spine level using the sensitivity analysis. This is followed by the development of more detailed FE model with viscoelastic modeling of the nucleus and the annulus. The dynamic load is applied on the superior vertebral body which follows triangular loading profile with 50ms rise time. The axial bulge is quantified at the center of the disc as this is the location of maximum deflection and local stress in the end-plate. The ratio of axial bulge and the total FSU deflection is plotted against magnitude of load applied to gain insight regarding the relation between load magnitude and axial bulge. This study will complement the research on end-plate fracture mechanism and its role in causing the burst fracture based on the magnitude of load.

scholarly journals A Constitutive Model for the Annulus of Human Intervertebral Disc: Implications for Developing a Degeneration Model and Its Influence on Lumbar Spine Functioning

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
J. Cegoñino ◽  
V. Moramarco ◽  
A. Calvo-Echenique ◽  
C. Pappalettere ◽  
A. Pérez del Palomar
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Annulus Fibrosus ◽  
Porous Matrix ◽  
Intervertebral Discs ◽  
Nonlinear Material ◽  
Theoretical Modelling ◽  
Fe Model ◽  
Spine Model

The study of the mechanical properties of the annulus fibrosus of the intervertebral discs is significant to the study on the diseases of lumbar intervertebral discs in terms of both theoretical modelling and clinical application value. The annulus fibrosus tissue of the human intervertebral disc (IVD) has a very distinctive structure and behaviour. It consists of a solid porous matrix, saturated with water, which mainly contains proteoglycan and collagen fibres network. In this work a mathematical model for a fibred reinforced material including the osmotic pressure contribution was developed. This behaviour was implemented in a finite element (FE) model and numerical characterization and validation, based on experimental results, were carried out for the normal annulus tissue. The characterization of the model for a degenerated annulus was performed, and this was capable of reproducing the increase of stiffness and the reduction of its nonlinear material response and of its hydrophilic nature. Finally, this model was used to reproduce the degeneration of the L4L5 disc in a complete finite element lumbar spine model proving that a single level degeneration modifies the motion patterns and the loading of the segments above and below the degenerated disc.

Selection of retroperitoneal access during intervertebral disc endoprosthesis in lumbar spine

2021 ◽  
Vol 23 (1) ◽  
pp. 73-80
Author(s):  
Maxim A. Priymak ◽  
Ivan A. Kruglov ◽  
Alexei I. Gaivoronski ◽  
Maksim N. Kravtsov ◽  
Gennady G. Bulyshchenko
Keyword(s):  
Lumbar Spine ◽  
Inferior Vena Cava ◽  
Intervertebral Disc ◽  
Inferior Vena ◽  
Vena Cava ◽  
Iliac Vein ◽  
Intervertebral Discs ◽  
Skin Incision ◽  
Common Iliac Vein ◽  
Left Common Iliac Vein

The morphometric parameters and surgical areas of risk of retroperitoneal approach were studied for endoprosthetics of intervertebral discs in the lumbar spine to reduce trauma and reduce the risk of complications. The study included 110 patients operated on in the period from 2017 to 2020 (72 men, 38 women) in the neurosurgical department of the 1586 Military Clinical Hospital. The average age of the patients was 44.9 15.4 years. According to the localization of access to the lumbar spine, the patients were distributed as follows: LIIILIV 8 (7.3%), LIVLV 46 (41.7%), LVSI 56 (51%). It was found that, for the intervertebral disc LV SI, the length of the skin incision was 92.5 (80; 100) mm, the length of the surgical wound was 80 (80; 110) mm, the thickness of the subcutaneous fat layer was 30 (15; 40) mm, the depth of the wound was to the spine 85 (70; 120) mm, the depth of the wound to the spinal canal 125 (107.5; 152.5) mm, the angle of operation in the horizontal plane at the level of the spine 52 (47; 59.5) degrees. On the basis of the anthropometric data of patients, the optimal length of the skin incision was determined for performing the retroperitoneal approach (120 mm for level LIIILIV, 100 mm for level LIVLV). Three variants of the inferior vena cava bifurcation have been identified for different levels of intervertebral discs in the lumbar spine: high bifurcation, left common iliac vein mainly overlaps the left half of the LIVLV intervertebral disc and does not overlap the LVSI intervertebral disc; middle bifurcation, left common iliac vein overlaps the central part of the intervertebral discs LIVLV and LVSI; low bifurcation, inferior vena cava overlaps the right side of the intervertebral disc LIVLV, inferior vena cava and left common iliac vein completely overlap the intervertebral disc LVSI. The data obtained can be used when planning retroperitoneal access to the lumbar spine in order to reduce the trauma of the operation.

Mechanical yield of the lumbar annulus: a possible contributor to instability

2014 ◽  
Vol 21 (4) ◽  
pp. 608-613 ◽  
Author(s):  
Brian D. Stemper ◽  
Jamie L. Baisden ◽  
Narayan Yoganandan ◽  
Barry S. Shender ◽  
Dennis J. Maiman
Keyword(s):  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Mechanical Response ◽  
Facet Joint ◽  
Intervertebral Discs ◽  
Stress And Strain ◽  
Anatomical Region ◽  
Linear Elastic ◽  
Load Carrying ◽  
Ultimate Failure

Object Segmental instability in the lumbar spine can result from a number of mechanisms including intervertebral disc degeneration and facet joint degradation. Under traumatic circumstances, elevated loading may lead to mechanical yield of the annular fibers, which can decrease load-carrying capacity and contribute to instability. The purpose of this study was to quantify the biomechanics of intervertebral annular yield during tensile loading with respect to spinal level and anatomical region within the intervertebral disc. Methods This laboratory-based study incorporated isolated lumbar spine annular specimens from younger and normal or mildly degenerated intervertebral discs. Specimens were quasi-statically distracted to failure in an environmentally controlled chamber. Stress and strain associated with yield and ultimate failure were quantified, as was stiffness in the elastic and postyield regions. Analysis of variance was used to determine statistically significant differences based on lumbar spine level, radial position, and anatomical region of the disc. Results Annular specimens demonstrated a nonlinear response consisting of the following: toe region, linear elastic region, yield point, postyield region, and ultimate failure point. Regional dependency was identified between deep and superficial fibers. Mechanical yield was evident prior to ultimate failure in 98% of the specimens and occurred at approximately 80% and 74% of the stress and strain, respectively, to ultimate failure. Fiber modulus decreased by 34% following yield. Conclusions Data in this study demonstrated that yielding of intervertebral disc fibers occurs relatively early in the mechanical response of the tissues and that stiffness is considerably decreased following yield. Therefore, yielding of annular fibers may result in decreased segmental stability, contributing to accelerated degeneration of bony components and possible idiopathic pain.

Melatonin: Protection of the Intervertebral Disc

2019 ◽  
Vol 2 (3) ◽  
pp. 1-9
Author(s):  
Russel J Reiter ◽  
Sergio Rosales-Corral ◽  
Ramaswamy Sharma
Keyword(s):  
Intervertebral Disc ◽  
Molecular Mechanisms ◽  
Intervertebral Discs ◽  
Lumbar Pain ◽  
Low Back ◽  
Work Time ◽  
Protective Actions ◽  
Aging Populations ◽  
Definition Of ◽  
Endogenous Melatonin

     Low back pain (lumbar pain) due to injury of or damage to intervertebral discs is common in all societies.  The loss of work time as a result of this problem is massive.  Recent research suggests that melatonin may prevent or counteract intervertebral disc damage. This may be especially relevant in aging populations given that endogenous melatonin, in most individuals, dwindles with increasing age. The publications related to melatonin and its protection of the intervertebral disc are reviewed herein, including definition of some molecular mechanisms that account for melatonin’s protective actions. 

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