scholarly journals Acute Surgical Injury Alters the Tensile Properties of Thoracolumbar Fascia in a Porcine Model

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Erika Nelson-Wong ◽  
Michal Glinka ◽  
Mamiko Noguchi ◽  
Helene Langevin ◽  
Gary J. Badger ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stretch Ratio ◽  
Testing System ◽  
Low Back ◽  
Tissue Stiffness ◽  
Biaxial Testing ◽  
Thoracolumbar Fascia ◽  
Injured Area ◽  
Injury Model ◽  
Local Injury

Recent work utilizing ultrasound imaging demonstrated that individuals with low back pain (LBP) have increased thickness and decreased mobility of the thoracolumbar fascia (TLF), an indication that the TLF may play a role in LBP. This study used a porcine injury model (microsurgically induced local injury)—shown to produce similar results to those observed in humans with LBP—to test the hypothesis that TLF mechanical properties may also be altered in patients with LBP. Perimuscular TLF tissue was harvested from the noninjured side of vertebral level L3-4 in pigs randomized into either control (n = 5) or injured (n = 5) groups. All samples were tested with a displacement-controlled biaxial testing system using the following protocol: cyclic loading/unloading and stress relaxation tests at 25%, 35%, and then 45% of their resting length. Tissue anisotropy was also explored by comparing responses to loading in longitudinal and transverse orientations. Tissues from injured pigs were found to have greater stretch–stretch ratio moduli (measure of tissue stiffness), less energy dissipation, and less stress decay compared to tissues from control pigs. Responses across these variables also depended on loading orientation. Clinical significance: these findings suggest that a focal TLF injury can produce impairments in tissue mechanical properties away from the injured area itself. This could contribute to some of the functional abnormalities observed in human LBP.

Effect of Bone Tumor and Osteoporosis on Mechanical Properties of Bone and Bone Tissue Properties: A Finite Element Study

2007 ◽  
Author(s):  
Vipul P. Gohil ◽  
Paul K. Canavan ◽  
Hamid Nayeb-Hashemi
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Bone Density ◽  
Bone Tissue ◽  
Bone Tumor ◽  
Cellular Structure ◽  
Bone Tumors ◽  
World Health ◽  
Tissue Stiffness ◽  
Tissue Properties

This research is aimed to study the variations in the biomechanical behavior of bone and bone tissues with osteoporosis and bone tumors. Osteoporosis and bone tumors reduce the mechanical strength of bone, which creates a greater risk of fracture. In the United States alone, ten million individuals, eight million of whom are women, are estimated to already have osteoporosis, and almost 34 million more are estimated to have low bone mass (osteopenia) placing them at increased risk for osteoporosis. World Health Organization defines osteopenia, as a bone density between one and two and a half standard deviations (SD) below the bone density of a normal young adult. (Osteoporosis is defined as 2.5 SD or more below that reference point.). Together, osteoporosis and osteopenia are expected to affect an estimated 52 million women and men age 50 and older by 2010, and 61 million by 2020. The current medical cost of osteoporosis total is nearly about $18 billion in the U.S. each year. There is a dearth of literature that addresses the effects of osteoporosis on bone tissue properties. Furthermore, there are few studies published related to the effect of bone tumors such as Adamantinoma of long bones, Aneurysmal bone cyst, Hemangioma and others on overall behavior of bone. To understand the variations in bio-mechanical properties of internal tissues of bone with osteoporosis and bone tumor, a 2D finite element (FE) model of bone is developed using ANSYS 9.0 ® (ANSYS Inc., Canonsburg, PA). Trabecular bone is modeled using hexagonal and voronoi cellular structure. This finite element model is subjected to change in BVF (bone volume fraction) and bone architecture caused by osteoporosis. The bone tumor is modeled as finer multi-cellular structure and the effects of its size, location, and property variation of tumor on overall bone behavior are studied. Results from this analysis and comparative data are used to determine behavior of bone and its tissue over different stage of osteoporosis and bone tumor. Results indicate that both bone tumor and osteoporosis significantly change the mechanical properties of the bone. The results show that osteoporosis increases the bone tissue stiffness significantly as BVF reduces. Bone tissue stiffness is found to increase by 80 percent with nearly 55 percent reduction of BVF. The results and methods developed in this research can be implemented to monitor variation in bio-mechanical properties of bone up to tissue level during medication or to determine type and time for need of external support such as bracing.

Thoracolumbar Fascia Enthesopathy as a Cause of Low Back Pain: A Retrospective and Follow-up Study

2021 ◽  
Author(s):  
Ouidade A. Tabesh ◽  
Roba Ghossan ◽  
Soha H Zebouni ◽  
Rafic Faddoul ◽  
Michel Revel ◽  
...  
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Iliac Crest ◽  
Pain Syndrome ◽  
Clinical Findings ◽  
Complete Relief ◽  
Low Back ◽  
Thoracolumbar Fascia ◽  
The Mean

Abstract Aim. To evaluate ultrasonography findings of Thoracolumbar Fascia (TLF) enthesis in patients with low back pain (LBP) due to iliac crest pain syndrome (ICPS). Method. The ultrasonographic and clinical findings of 60 patients with LBP due to ICPS were compared to those of 30 healthy volunteers with no LBP. Thickness of the TLF was measured with ultrasound (US) at its insertion on the iliac crest. Results. Forty-eight women and 12 men with a mean age of 42.1±11.3 years were diagnosed with ICPS. In patients, the mean thickness of the TLF was 2.51±0.70mm in affected sides compared to 1.81±0.44mm in the contralateral unaffected sides. The mean thickness difference of 0.82mm between the affected and non-affected sides was statistically significant (95%CI, 0.64-0.99, P<0.0001). In volunteers, the mean thickness of the TLF was 1.6±0.2mm. The mean thickness difference of 0.89mm between the affected sides of patients and volunteers was statistically significant (95%CI, 0.73-1.06, P<0.0001). Forty-two patients who didn’t improve with conservative therapy, received injections of methylprednisolone acetate and 1% lidocaine around the TLF enthesis. All patients reported complete relief of their LBP within 20 minutes of the injections thanks to the lidocaine anesthetic effect. Fifty-six (93.3%) patients were reached by phone for a long-term follow-up. Among them, 33 (58.9%) patients experienced a sustained complete pain relief after a mean follow-up of 45±19.3 months (range, 3-74 months). Conclusion. our findings suggest that TLF enthesopathy is a potential cause of nonspecific LBP that can be diagnosed using US.

Effect of temperature on the biaxial mechanics of excised lung parenchyma of the dog

1992 ◽  
Vol 73 (3) ◽  
pp. 1171-1180 ◽  
Author(s):  
J. C. Debes ◽  
Y. C. Fung
Keyword(s):  
Mechanical Properties ◽  
Lung Parenchyma ◽  
Tensile Tests ◽  
Stretch Ratio ◽  
Effect Of Temperature ◽  
Uniaxial Tensile ◽  
Slow Cooling ◽  
Influence Of Temperature On ◽  
Creep And Stress Relaxation ◽  
Tissue Material

The influence of temperature on the mechanical properties of excised saline-filled lung parenchyma of the dog was studied at low lung volume. The motivation of this study was to determine whether lung tissue material without the influence of surface tension undergoes a phase transition in the 20–40 degrees C range, as does synthetic elastin studied by Urry in 1984–1986. Dynamic biaxial and uniaxial tensile tests were done, and strain vs. Lagrangian stress curves were recorded during slow cooling and heating between 40 and 10 degrees C. To emphasize the effects of elastin, strains (defined as stretch ratio minus one) were kept below 30%. A slight decrease in compliance occurred with cooling over the entire temperature range. This effect may be attributed to collagen. It was accompanied by a gradual increase in length as the tissue cooled, an effect that may be attributed to elastin. This process was partially reversible with reheating. However, this effect is in contrast with the sudden drastic change in mechanical properties of synthetic elastin described by Urry. Hysteresis, creep, and stress relaxation were small at these low strains. Possible causes of these effects are discussed.

scholarly journals Low Dielectric Constant Polyimide Obtained by Four Kinds of Irradiation Sources

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 879 ◽  
Author(s):  
Hongxia Li ◽  
Jianqun Yang ◽  
Shangli Dong ◽  
Feng Tian ◽  
Xingji Li
Keyword(s):  
Mechanical Properties ◽  
Dielectric Constant ◽  
Electrical Properties ◽  
Photoelectron Spectroscopy ◽  
Polymer Materials ◽  
Testing System ◽  
Paramagnetic Resonance ◽  
Low Dielectric ◽  
Modification Technique ◽  
The Fourier Transform

Irradiation is a good modification technique, which can be used to modify the electrical properties, mechanical properties, and thermal properties of polymer materials. The effects of irradiation on the electrical properties, mechanical properties, and structure of polyimide (PI) films were studied. PI films were irradiated by a 1 MeV electron, 3 MeV proton, 10 MeV proton, and 25 MeV carbon ion. Dielectric constant, dielectric loss, and resistance measurements were carried out to evaluate the changes in the electrical properties; moreover, the mechanical properties of the pristine and irradiated PI were analyzed by the tensile testing system. The irradiation induced chemical bonds and free radicals changes of the PI films were confirmed by the Fourier transform infrared (FTIR) spectra, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR). The dielectric constant of the PI films decreases with the increase of fluences by the four kinds of irradiation sources.

Mechanical Properties Characterization of Abdominal Aortic Aneurysm Tissue Using Biaxial Testing

2002 ◽  
Author(s):  
Steven P. Marra ◽  
Francis E. Kennedy ◽  
Mark F. Fillinger
Keyword(s):  
Mechanical Properties ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Imaging Techniques ◽  
Constitutive Law ◽  
Patient Specific ◽  
Biaxial Testing ◽  
Abdominal Aortic ◽  
Mechanical Properties Characterization

An abdominal aortic aneurysm (AAA) is an abnormal, localized enlargement of the aorta. If untreated, a AAA will continue to enlarge in size and eventually rupture. Currently, AAA diameter is used as the principal indicator of impending rupture. However, this method it is not totally reliable. In an effort to improve the estimation of rupture risk, some researchers are currently studying the mechanical wall stresses of AAAs using patient-specific medical imaging techniques and finite element modeling [1,2]. The accuracy of these models depends significantly on the constitutive law used to describe the mechanical properties of the AAA tissue. To date, only isotropic constitutive laws have been used in these models.

Anatomical study of superior cluneal nerve entrapment

2013 ◽  
Vol 19 (1) ◽  
pp. 76-80 ◽  
Author(s):  
Hiroshi Kuniya ◽  
Yoichi Aota ◽  
Tomoyuki Saito ◽  
Yoshinori Kamiya ◽  
Kengo Funakoshi ◽  
...  
Keyword(s):  
Iliac Crest ◽  
Anatomical Study ◽  
Anatomical Variations ◽  
Lateral Branch ◽  
Medial Branch ◽  
Low Back ◽  
Thoracolumbar Fascia ◽  
Recent Clinical Study ◽  
Lateral Branches ◽  
The Right

Object Entrapment of the superior cluneal nerve (SCN) in an osteofibrous tunnel in the space surrounded by the iliac crest and the thoracolumbar fascia is a cause of low-back pain (LBP). Several anatomical and surgical reports describe SCN entrapment as a cause of LBP, and a recent clinical study reported that patients with suspected SCN disorder constitute approximately 10% of the patients suffering from LBP and/or leg symptoms. However, a detailed anatomical study of SCN entrapment is rare. The purpose of this study was to investigate the courses of SCN branches and to ascertain the frequency of SCN entrapment. Methods Branches of the SCN were dissected in 109 usable specimens (54 on the right side and 55 on the left side) obtained in 59 formalin-preserved cadavers (average age at death 84.8 years old). All branches were exposed at the points where they perforated the thoracolumbar fascia. The presence or absence of an osteofibrous tunnel was ascertained and, if present, the entrapment of the branches in the tunnel was determined. Results Of 109 specimens, 61 (56%) had at least 1 branch running through an osteofibrous tunnel. Forty-two medial (39%), 30 intermediate (28%), and 14 lateral (13%) SCN branches passed through such a tunnel. Of these, only 2 medial branches had obvious entrapment in an osteofibrous tunnel. There were several patterns for the SCN course through the tunnel: medial branch only (n = 25), intermediate branch only (n = 11), lateral branch only (n = 4), medial and intermediate branches (n = 11), medial and lateral branches (n = 2), intermediate and lateral branches (n = 4), and all branches (n = 4). Conclusions Several anatomical variations of the running patterns of SCN branches were detected. Entrapment was seen only in the medial branches. Although obvious entrapment of the SCN is rare, it may cause LBP.

Sensory findings after stimulation of the thoracolumbar fascia with hypertonic saline suggest its contribution to low back pain

Pain ◽  
2014 ◽  
Vol 155 (2) ◽  
pp. 222-231 ◽  
Author(s):  
Andreas Schilder ◽  
Ulrich Hoheisel ◽  
Walter Magerl ◽  
Justus Benrath ◽  
Thomas Klein ◽  
...  
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Hypertonic Saline ◽  
Low Back ◽  
Thoracolumbar Fascia ◽  
Stimulation Of

A Comparison of Uniaxial and Biaxial Mechanical Properties of the Annulus Fibrosus: A Porcine Model

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Diane E. Gregory ◽  
Jack P. Callaghan
Keyword(s):  
Mechanical Properties ◽  
Annulus Fibrosus ◽  
Axial Direction ◽  
Stretch Ratio ◽  
Intervertebral Disk ◽  
Circumferential Direction ◽  
Biaxial Tests ◽  
Maximal Stress ◽  
Biaxial Mechanical Properties

The annulus fibrosus of the intervertebral disk experiences multidirectional tension in vivo, yet the majority of mechanical property testing has been uniaxial. Therefore, our understanding of how this complex multilayered tissue responds to loading may be deficient. This study aimed to determine the mechanical properties of porcine annular samples under uniaxial and biaxial tensile loading. Two-layer annulus samples were isolated from porcine disks from four locations: anterior superficial, anterior deep, posterior superficial, and posterior deep. These tissues were then subjected to three deformation conditions each to a maximal stretch ratio of 1.23: uniaxial, constrained uniaxial, and biaxial. Uniaxial deformation was applied in the circumferential direction, while biaxial deformation was applied simultaneously in the circumferential and compressive directions. Constrained uniaxial consisted of a stretch ratio of 1.23 in the circumferential direction while holding the tissue stationary in the axial direction. The maximal stress and stress-stretch ratio (S-S) moduli determined from the biaxial tests were significantly higher than those observed during both the uniaxial tests (maximal stress, 97.1% higher during biaxial; p=0.002; S-S moduli, 117.9% higher during biaxial; p=0.0004) and the constrained uniaxial tests (maximal stress, 46.8% higher during biaxial; S-S moduli, 82.9% higher during biaxial). These findings suggest that the annulus is subjected to higher stresses in vivo when under multidirectional tension.

scholarly journals Study of Biaxial Mechanical Properties of the Passive Pig Heart: Material Characterisation and Categorisation of Regional Differences

2020 ◽  
Author(s):  
Fulufhelo Nemavhola
Keyword(s):  
Mechanical Properties ◽  
Computational Models ◽  
Heart Diseases ◽  
Interventricular Septum ◽  
Constitutive Modelling ◽  
Tissue Mechanics ◽  
Material Behaviour ◽  
Biaxial Testing ◽  
African Countries ◽  
Biaxial Tests

Regional mechanics of the heart is vital in the development of accurate computational models for the pursuit of relevant therapies. Challenges related to heart dysfunctioning are the most important sources of mortality in the world. For example, myocardial infarction (MI) is the foremost killer in sub-Saharan African countries. Mechanical characterisation plays an important role in achieving accurate material behaviour. Material behaviour and constitutive modelling are essential for accurate development of computational models. In most cases previously, the mechanical properties of the heart myocardium were assumed to be homogeneous. The main objective of this paper is to determine the mechanical material properties of healthy porcine myocardium in three regions, namely left ventricle (LV), mid-wall/interventricular septum (MDW) and right ventricle (RV). The biomechanical properties of the pig heart RV, LV and MDW were characterised using biaxial testing. The biaxial tests show the pig heart myocardium behaves non-linearly, heterogeneously and anisotropically. In this study, it was shown that RV, LV and MDW may exhibit slightly different mechanical properties. Data presented here may be helpful in regional tissue mechanics, especially for the understanding of various heart diseases and development of new therapies.

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