Download or read book A Mathematical Model of the Human Lumbar Motion Segment Under Flexion compression written by Ali Mehdi Elhagediab and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Three Dimensional Finite Element Model to Study the Biomechanical and Kinematic Characteristics of the Human Lumbar Spine in Flexion written by Dhruv Jitesh Mehta and published by . This book was released on 2007 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of the research was to develop a three-dimensional finite element model to study the biomechanical and kinematic characteristics of the human lumbar spine in flexion. An analytical model of the lumbar spine capable of taking into consideration the actual geometry, non-linear material properties and realistic loading would be of benefit in studying normal biomechanics, as well as in-vivo behavior in injured and surgically altered spines. Fundamental to this approach is an accurate model of the spine. This was achieved by modeling the lumbar segments L2-L4 from Computed Tomography (CT) data and analyzing them under loading conditions that best approximated the human lumbar segments in flexion. An in-vitro study was performed for validation of the finite element model. Human lumbar cadaveric spinal segments (L2-L4) were loaded based on test conditions similar to those defined in the finite element analysis. The results of the cadaver biomechanical study and finite element analysis were compared. The results suggest that the model is a valid approach to assessing the range of motion of the L3 segment under flexion. Rotation under lateral bending moments was additionally investigated to provide a thorough validation of the model.

Download or read book Biomechanics of the Spine written by Fabio Galbusera and published by Academic Press. This book was released on 2018-04-23 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biomechanics of the Spine encompasses the basics of spine biomechanics, spinal tissues, spinal disorders and treatment methods. Organized into four parts, the first chapters explore the functional anatomy of the spine, with special emphasis on aspects which are biomechanically relevant and quite often neglected in clinical literature. The second part describes the mechanics of the individual spinal tissues, along with commonly used testing set-ups and the constitutive models used to represent them in mathematical studies. The third part covers in detail the current methods which are used in spine research: experimental testing, numerical simulation and in vivo studies (imaging and motion analysis). The last part covers the biomechanical aspects of spinal pathologies and their surgical treatment. This valuable reference is ideal for bioengineers who are involved in spine biomechanics, and spinal surgeons who are looking to broaden their biomechanical knowledge base. The contributors to this book are from the leading institutions in the world that are researching spine biomechanics. - Includes broad coverage of spine disorders and surgery with a biomechanical focus - Summarizes state-of-the-art and cutting-edge research in the field of spine biomechanics - Discusses a variety of methods, including In vivo and In vitro testing, and finite element and musculoskeletal modeling

Download or read book Experimental and Analytical Modeling of the in Vivo and in Vitro Biomechanical Behavior of the Human Lumbar Spine written by Tov I. Vestgaarden and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: This dissertation has two major parts; Analytical and Experimental. The analytical section contains a study using Finite Element Analysis of dynamic instrumentation to demonstrate stress reduction in adjacent level discs. The experimental section contains biomechanical testing of facet fusion allograft technique and finally a comparison between In Vivo and In Vitro intradiscal pressures to determine forces acting on Lumbar spine segment L4-L5. A comprehensive study of available data, technology and literature was done. Conventional fusion instrumentation is believed to accelerate the degeneration of adjacent discs due to the increased stresses caused by motion discontinuity. A three dimensional finite element model of the lumbar spine was obtained which simulated flexion and extension. Reduced stiffness and increased axial motion of dynamic posterior lumbar fusion instrumentation designs results in a ~10% cumulative stress reduction for each flexion cycle. The cumulative effect of this reduced amplitude and distribution of peak stresses in the adjacent disc may partially alleviate the problem of adjacent level disc degeneration. Traditionally a pedicle screw system has been used for fixation of the lumbar spine and this involves major surgery and recovery time. Facet fixation is a technique that has been used for stabilization of the lumbar spine. The cadaver segments were tested in axial rotation, combined flexion/extension and lateral bending. Implantation of the allograft dowel resulted in a significant increase in stiffness compared to control. Facet fusion allograft provides an effective minimally invasive method of treating debilitating pain caused by deteriorated facet joints by permanently fusing them. An In Vitro biomechanical study was conducted to determine the intradiscal pressure during spinal loading. The intradiscal pressures in flexion/extension, lateral bending and axial rotation was compared to In Vivo published data. There is no data that explains the actual forces acting on the spine during flexion, extension, lateral bending or axial rotation. The functional spinal units were tested in combined axial compression and flexion/extension, combined axial compression and lateral bending and combined axial compression and axial rotation using a nondestructive testing method. Overall, this study found a good correlation between In Vivo and In Vitro data. This can essentially be used to make physiological relation from experimental and analytical evaluations of the lumbar spine. It is important to know how much load needs to be controlled by an implant.

Download or read book An Analytical Investigation of Ligamentous Lumbar Spine Mechanics written by Kim Young Eun and published by . This book was released on 1988 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Axial Twist of the Lumbar Spine written by Colin David McKinnon and published by . This book was released on 2017 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: While a link between magnitudes of spinal axial twist motions and the various modes of associated injury, pain reporting, and lost time claims has been tentatively established, there is need for greater investigation and understanding of the mechanical impact of axial twist motions. Researchers have compiled data sets demonstrating the relationship between twisting motions and moments and low back injury outcomes, but do not create a link to gross occupational exposures. Further, few studies can create a direct relationship between workstation design, trunk postures, and spine joint specific pain and failure mechanisms. When this limited mechanistic understanding is paired with injury prevalence statistics, they highlight a clear need to investigate the role of tissue-level axial twist exposures on occupational injury risk and workstation design guidelines to mitigate that risk. The global objective of this research was focused on developing a relationship between working axial twist postures and intervertebral joint injury risk. The four specific questions asked were (1) What is the relationship between externally measured thoracopelvic axial twist and the actual segmental axial twist motion of the intervertebral joints? (2) Can we use ultrasound as a modality to consistently and accurately measure vertebral axial twist motion? (3) What amount of lumbar axial twist presents an elevated injury risk for working populations? (4) What movement strategies do people use to perform reaching tasks at different hand locations, and how do task parameters impact these strategies? Study 1: Ultrasound has the potential for use to evaluate boney movement during axial twist of the lumbar spine in both in vivo and in vitro evaluations. Such segmental rotations could then be measured under controlled external thoracic axial twist conditions and in response to mechanical loading. The purpose of this study was to measure vertebral segmental rotations in a porcine model of the human lumbar spine using an ultrasound imaging protocol, and to validate use of this imaging technique with an optical motion capture system. Twelve porcine functional spinal units were fixed to a mechanical testing system, and compression (15% of compressive tolerance), flexion-extension, and axial twist (0, 2, 4, or 6 degrees) were applied. Axial twist motion was tracked using an optical motion capture system and posterior surface ultrasound. Correlation between the two measurement systems was greater than 0.903 and absolute system error was 0.014 across all flexion-extension postures. These findings indicate that ultrasound can be used to track axial twist motion in an in vitro spine motion segment and has the potential for use in vivo to evaluate absolute intervertebral axial twist motion. Study 2: The relationship between externally measured and internal spine axial twist motion is not well understood. Ultrasound is a validated technique (Study 1) for measurement of vertebral axial twist motion and has the potential for measuring segmental vertebral axial twist in vivo. The purpose of this study was to evaluate lumbar segmental axial twist in relation to external thoracopelvic twist using an ultrasound imaging technique. Sixteen participants kneeled in a custom-built axial twist jig which isolated motion to the lumbar spine. Participants twisted from neutral to 75% of maximum twist range of motion in an upright flexion-extension posture. Thoracopelvic motion was recorded with a motion capture system and L1 to S1 vertebral axial twist was recorded using ultrasound. Maximum thoracopelvic axial twist motion was 41.1 degrees. The majority of axial twist motion occurred at the L2-L3 (46.8% of lumbar axial twist motion) and L5-S1 (33.5%) intervertebral joints. Linear regression fits linking axial twist at each vertebral level to thoracopelvic axial twist ranged from 0.43 to 0.79. These findings demonstrate a mathematical relationship between internal and external axial twist motion, and suggest that classic use of L4-L5 to represent lumbar spine motion may not be appropriate for axial twist modeling approaches. Study 3: Axial twisting exposures have been repeatedly identified as a risk factor for occupational low back pain and injury, but there is a need for an improved understanding of the role of axial twist magnitude and associated moment as modifiers of the cumulative load tolerance of intervertebral joints. The purpose of this study was to mathematically characterize the relationship between axial twist motion magnitudes and the cumulative load tolerance of porcine cervical functional spinal units. Twenty-four porcine functional spinal units were fixed in a mechanical testing system under compressive load (15% of compressive tolerance) and in a neutral flexion-extension posture. Specimens were axially twisted to 5, 7.5, 10, 12.5, 15 or 17.5 degrees at 1 Hz until failure or 21 600 total cycles. Cumulative applied axial twist was recorded, and exponential functions were fit to the twist magnitude-cumulative twist moment recordings. Weighting-factor functions for cumulative axial twist moment injury risk were developed based on absolute axial twist magnitude and twist normalized to maximum range of motion. The non-linear weighting-factors have potential use in assessment of cumulative axial twist injury risk in occupational tasks. Study 4: The magnitude of axial twist in the lumbar spine in relation to reaching tasks is currently unknown. Therefore, the purpose of this study was to investigate lumbar spine axial twist during simulated occupational tasks across a range of forward and lateral reach distances, task heights, and exertion directions. Twenty-four participants performed single-handed, right-handed exertions against a load cell in three directions (upward, downward, forward push), at two heights (shoulder, elbow), and at 11 different hand target locations corresponding to current ergonomic reach guidelines. Thoracopelvic and right upper limb postures were recorded using an optical motion capture system, and trunk muscle activation was recorded using surface electromyography. Participants performed a contralateral twist at both the thoracopelvic spine and pelvis about the feet for directly forward hand targets, and twisted up to 19.9 degrees and 12.1 degrees at the lumbar spine and pelvis, respectively, at the most lateral hand target locations. Lumbar flexion and shoulder elevation each increased with reach distance to a maximum of 5.6 degrees and 64.9 degrees, respectively, at the furthest, directly forward hand target location. Hip and abdominal muscle activation exceeded 10% MVC for the most lateral hand target locations, and exhibited the highest activation for upward and forward push exertions. These findings suggest that future ergonomics guidelines should assess reaching and exertion tasks to hand target locations beyond 60-degrees from the midline of the body and consider them as non-optimal zones. The collection of studies in this thesis was structured to improve current ergonomics reach guidelines and provide a physiological and biomechanical basis for reach distance recommendations incorporating the low back. The findings from these studies have important implications for researchers, ergonomists, and clinicians assessing injury risk related to twisted occupational postures.

Download or read book Mechanical Analogue Model of the Human Lumbar Spine written by CD. Pence and published by . This book was released on 2003 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanical testing of spinal instrumentation on cadaveric spine segments can be challenging. In this study, a mechanical analogue lumbar spine model was developed to be similar in rigidity to that of cadaveric spine segments. Three models of an adult human lumbar spine were built from composite vertebrae, ligaments and discs created individually to reproduce the nonlinear mechanical properties of human components. These models and three calf lumbar spines were loaded in a biaxial mechanical test system in axial compression, torsion, right and left lateral bending, flexion and extension. Rigidities were calculated in the secondary linear load-displacement region. Load-displacement behavior was nonlinear for both analogue and calf spines. There was good reproducibility between the models. Average axial rigidity of the analogue spines was 86 N/mm versus 231 N/mm for the calf spines, possibly due to the calf flat-back. In the remaining loading modes, the analogue spine was 26-65% more rigid than young calf spines. Comparisons to human cadaveric spine segments are underway.

Download or read book Musculoskeletal Disorders and the Workplace written by Institute of Medicine and published by National Academies Press. This book was released on 2001-05-24 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: Every year workers' low-back, hand, and arm problems lead to time away from jobs and reduce the nation's economic productivity. The connection of these problems to workplace activities-from carrying boxes to lifting patients to pounding computer keyboards-is the subject of major disagreements among workers, employers, advocacy groups, and researchers. Musculoskeletal Disorders and the Workplace examines the scientific basis for connecting musculoskeletal disorders with the workplace, considering people, job tasks, and work environments. A multidisciplinary panel draws conclusions about the likelihood of causal links and the effectiveness of various intervention strategies. The panel also offers recommendations for what actions can be considered on the basis of current information and for closing information gaps. This book presents the latest information on the prevalence, incidence, and costs of musculoskeletal disorders and identifies factors that influence injury reporting. It reviews the broad scope of evidence: epidemiological studies of physical and psychosocial variables, basic biology, biomechanics, and physical and behavioral responses to stress. Given the magnitude of the problem-approximately 1 million people miss some work each year-and the current trends in workplace practices, this volume will be a must for advocates for workplace health, policy makers, employers, employees, medical professionals, engineers, lawyers, and labor officials.

Download or read book Clinical Anatomy of the Lumbar Spine and Sacrum written by Nikolai Bogduk and published by Elsevier Health Sciences. This book was released on 2005-01-01 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bogduk aims to provide a foundation of knowledge upon which an understanding of the various treatment and therapy techniques of the different specialities involved can be built. This edition includes discussion of the sacrum and sacro-iliac joint.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1988 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Journal of Rehabilitation Research and Development written by and published by . This book was released on 1985 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Journal of Rehabilitation Research Development written by and published by . This book was released on 2000 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Masters Theses in the Pure and Applied Sciences written by W. H. Shafer and published by Plenum Publishing Corporation. This book was released on 1992 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses Listed by Discipline: Aerospace Engineering. Agricultural Economics, Sciences and Engineering. Architechtural Engineering and Urban Planning. Astronomy. Astrophysics. Ceramic Engineering. Communications Engineering and Computer Science. Cryogenic Engineering. Electrical Engineering. Engineering Mechanics. Engineering Physics. Engineering Science. Fuels, Combustion, and Air Pollution. General and Environmental Engineering. Geochemistry and Soil Science. Geological Sciences and Geophysical Engineering. Geology and Earth Science. Geophysics. Industrial Engineering. Marine and Ocean Engineering. Materials Science and Engineering. Mechanical Engineering and Bioengineering. Metallurgy. Meteorology and Atmospheric Science. 17 additional disciplines. Index.

Download or read book Lumbar Injury Biomechanics written by Jeffrey A Pike and published by SAE International. This book was released on 2013-08-01 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: The amount of load that can be borne by the different components of the lumbar region is fairly well understood, as are resulting injuries from overloading. Less severe lumbar injuries involve a wide range of factors, including: heredity, obesity, age, occupation, sports, cardiovascular risk factors, and depression. Some of the most painful conditions that require high levels of care involve lumbar spine fracture or soft tissue injury from falls, contact sports, vehicle collisions, aircraft ejection, and underbody blasts from roadway explosions (military injuries). Each of these injury scenarios elicits a different kinematic response of the spine as a result of load direction, magnitude, and duration. Updated from a popular earlier volume, this new compendium includes landmark papers from 1994 through 2013 that focus exclusively on lumbar injuries. It also features an introductory chapter, “Blunt Lumbar Trauma” that provides an overview of the anatomy of the lumbar region, injury, and injury mechanisms, as well as an extensive literature update. This edition is the third in a series of biomechanics compendia edited by Mr. Pike. Earlier editions covered injuries of the neck and head. For this volume, Mr. Pike and the advisory panel selected 15 of the best papers from a variety of sources including SAE International, IRCOBI, Stapp, NHTSA, ESV, and the Association for the Advancement of Automotive Medicine. The book will be helpful to those studying lumbar injury from a broad range of causes, including transportation, falls, sports, personal violence, and blast-related. Professionals from a variety of disciplines will find the book useful: biomechanics, accident reconstruction, medical and rehabilitation, insurance, legal, and law enforcement.

Download or read book Mathematical and Computational Methods in Biomechanics of Human Skeletal Systems written by Jiri Nedoma and published by John Wiley & Sons. This book was released on 2011-06-09 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cutting-edge solutions to current problems in orthopedics, supported by modeling and numerical analysis Despite the current successful methods and achievements of good joint implantations, it is essential to further optimize the shape of implants so they may better resist extreme long-term mechanical demands. This book provides the orthopedic, biomechanical, and mathematical basis for the simulation of surgical techniques in orthopedics. It focuses on the numerical modeling of total human joint replacements and simulation of their functions, along with the rigorous biomechanics of human joints and other skeletal parts. The book includes: An introduction to the anatomy and biomechanics of the human skeleton, biomaterials, and problems of alloarthroplasty The definition of selected simulated orthopedic problems Constructions of mathematical model problems of the biomechanics of the human skeleton and its parts Replacement parts of the human skeleton and corresponding mathematical model problems Detailed mathematical analyses of mathematical models based on functional analysis and finite element methods Biomechanical analyses of particular parts of the human skeleton, joints, and corresponding replacements A discussion of the problems of data processing from nuclear magnetic resonance imaging and computer tomography This timely book offers a wealth of information on the current research in this field. The theories presented are applied to specific problems of orthopedics. Numerical results are presented and discussed from both biomechanical and orthopedic points of view and treatment methods are also briefly addressed. Emphasis is placed on the variational approach to the investigated model problems while preserving the orthopedic nature of the investigated problems. The book also presents a study of algorithmic procedures based on these simulation models. This is a highly useful tool for designers, researchers, and manufacturers of joint implants who require the results of suggested experiments to improve existing shapes or to design new shapes. It also benefits graduate students in orthopedics, biomechanics, and applied mathematics.

Download or read book The Head neck Sensory Motor System written by A. Berthoz and published by . This book was released on 1992 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the most comprehensive and up-to-date account of the control of vertebrate head movements and its biomechanical and neural basis. It covers the entire spectrum of research on head-neck movements, ranging from the global description and analysis of a particular behavior to its underlying mechanisms at the level of neurotransmitter release and membrane biophysics.

Download or read book The Lumbar Spine written by Harry N. Herkowitz and published by Lippincott Williams & Wilkins. This book was released on 2004 with total page 1018 pages. Available in PDF, EPUB and Kindle. Book excerpt: The official publication of the International Society for the Study of the Lumbar Spine, this volume is the most authoritative and up-to-date reference on the lumbar spine. This edition provides more balance between basic science and clinical material and has been completely reorganized for easy reference. New chapters cover gene therapy, outcomes assessment, and alternatives to traditional nonoperative treatment. The editors have also added chapters on preparation for surgery, surgical approaches, spinal instrumentation, and bone grafts. Chapters on specific disorders have a consistent structure—definition, natural history, physical examination, imaging, nonoperative treatment, operative treatment, postoperative management, results of surgery, and complications.