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Spinal biomechanics

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https://www.readbyqxmd.com/read/28224297/fracture-reduction-by-postoperative-mobilisation-for-the-treatment-of-hyperextension-injuries-of-the-thoracolumbar-spine-in-patients-with-ankylosing-spinal-disorders
#1
Richard A Lindtner, Christian Kammerlander, Michael Goetzen, Alexander Keiler, Davud Malekzadeh, Dietmar Krappinger, Rene Schmid
INTRODUCTION: The aim of this study was to evaluate results of surgical stabilisation of hyperextension injuries of the thoracolumbar spine in patients with ankylosing spinal disorders using two different treatment strategies: the conventional open rigid posterior instrumentation and percutaneous less rigid posterior instrumentation. Surgical and non-surgical complications, the postoperative radiological course, and clinical outcome at final follow-up were comparatively assessed. Moreover, we sought to discuss important biomechanical and surgical aspects specific to posterior instrumentation of the ankylosed thoracolumbar spine as well as to elaborate on the advantages and limitations of the proposed new treatment strategy involving percutaneous less rigid stabilisation and fracture reduction by postoperative mobilisation...
February 21, 2017: Archives of Orthopaedic and Trauma Surgery
https://www.readbyqxmd.com/read/28222402/impact-of-anchor-type-on-porcine-lumbar-biomechanics-finite-element-modelling-and-in-vitro-validation
#2
Martin Brummund, Vladimir Brailovski, Yvan Petit, Yann Facchinello, Jean-Marc Mac-Thiong
BACKGROUND: Rigid posterior implants used for spinal stabilization can be anchored to the vertebrae using pedicle screws or screws combined with transverse process hooks. In the present study, a finite element model of a porcine lumbar spine instrumented with screws and hooks is presented and validated. METHODS: The porcine lumbar spine model was validated using in-vitro measurements on six porcine specimens. Validation metrics included intervertebral rotations (L1 to L6) and nucleus pressure in the topmost cranial instrumented disc...
February 14, 2017: Clinical Biomechanics
https://www.readbyqxmd.com/read/28215399/restoring-standing-capabilities-with-feedback-control-of-functional-neuromuscular-stimulation-following-spinal-cord-injury
#3
REVIEW
Raviraj Nataraj, Musa L Audu, Ronald J Triolo
This paper reviews the field of feedback control for neuroprosthesis systems that restore advanced standing function to individuals with spinal cord injury. Investigations into closed-loop control of standing by functional neuromuscular stimulation (FNS) have spanned three decades. The ultimate goal for FNS standing control systems is to facilitate hands free standing and enabling the user to perform manual functions at self-selected leaning positions. However, most clinical systems for home usage currently only provide basic upright standing using preprogrammed stimulation patterns...
February 15, 2017: Medical Engineering & Physics
https://www.readbyqxmd.com/read/28207656/biomechanical-evaluation-of-transpedicular-nucleotomy-with-intact-annulus-fibrosus
#4
Fabrizio Russo, Robert A Hartman, Kevin M Bell, Nam Vo, Gwendolyn A Sowa, James D Kang, Gianluca Vadalà, Vincenzo Denaro
STUDY DESIGN: Biomechanical testing of partially nucleotomized ovine cadaveric spines. OBJECTIVE: To explore how the nucleus pulposus (NP) affects the biomechanical behavior of the intervertebral disc (IVD) by performing a partial nucleotomy via the transpedicular approach. SUMMARY OF BACKGROUND DATA: Mechanical loading represents a crucial part of IVD homeostasis. However, traditional regenerative strategies require violation of the annulus fibrosus (AF) resulting in significant alteration of joint mechanics...
February 15, 2017: Spine
https://www.readbyqxmd.com/read/28195302/testing-biomechanical-models-of-human-lumbar-lordosis-variability
#5
Eric R Castillo, Connie Hsu, Ross W Mair, Daniel E Lieberman
OBJECTIVES: Lumbar lordosis (LL) is a key adaptation for bipedalism, but factors underlying curvature variations remain unclear. This study tests three biomechanical models to explain LL variability. MATERIALS AND METHODS: Thirty adults (15 male, 15 female) were scanned using magnetic resonance imaging (MRI), a standing posture analysis was conducted, and lumbar range of motion (ROM) was assessed. Three measures of LL were compared. The trunk's center of mass was estimated from external markers to calculate hip moments (Mhip ) and lumbar flexion moments...
February 13, 2017: American Journal of Physical Anthropology
https://www.readbyqxmd.com/read/28190488/effect-of-a-titanium-cage-as-a-stand-alone-device-on-biomechanical-stability-in-the-lumbosacral-spine-of-canine-cadavers
#6
M Teunissen, A J van der Veen, T H Smit, M A Tryfonidou, B P Meij
Degenerative lumbosacral stenosis is a common disease in dogs characterised by intervertebral disc herniation, loss of disc height and stenosis. Decompressive dorsal laminectomy and partial discectomy can cause spinal instability and worsen foraminal stenosis. Pedicle screw and rod fixation (PSRF) with an intervertebral body cage allows for distraction and restoration of disc height and restores foraminal apertures. The aim of this study was to evaluate the ex vivo biomechanical properties of a titanium intervertebral cage alone and in combination with PSRF in the lumbosacral spine of dogs...
February 2017: Veterinary Journal
https://www.readbyqxmd.com/read/28185981/analysis-of-the-s2-alar-iliac-screw-as-compared-with-the-traditional-iliac-screw-does-it-increase-stability-with-sacroiliac-fixation-of-the-spine
#7
Daniel G Hoernschemeyer, Troy D Pashuck, Ferris M Pfeiffer
BACKGROUND CONTEXT: Arthrodesis of the lumbosacral junction continues to be a challenge in pediatric and adult spinal deformity surgery. PURPOSE: To evaluate the biomechanical rigidity of two types of lumbosacral fixation. Our hypothesis was that the use of S2 alar-iliac (S2AI) fixation will result in statistically similar biomechanical fixation as compared with use of an iliac screw with a 95% confidence interval. STUDY SETTING: Controlled biomechanical laboratory METHODS: Ten human cadaveric lumbosacral specimens were separated into two test groups: (1) S2AI (n=5) and (2) iliac screw (n=5)...
February 6, 2017: Spine Journal: Official Journal of the North American Spine Society
https://www.readbyqxmd.com/read/28167249/how-are-adjacent-spinal-levels-affected-by-vertebral-fracture-and-by-vertebroplasty-a-biomechanical-study-on-cadaveric-spines
#8
Jin Luo, Deborah J Annesley-Williams, Michael A Adams, Patricia Dolan
BACKGROUND CONTEXT: Spinal injuries and surgery may have important effects at neighbouring spinal levels, but previous investigations of adjacent-level biomechanics have produced conflicting results. We use 'stress profilometry' and non-contact strain measurements to investigate thoroughly this long-standing problem. PURPOSE: To determine how vertebral fracture and vertebroplasty affect compressive load-sharing and vertebral deformations at adjacent spinal levels...
February 3, 2017: Spine Journal: Official Journal of the North American Spine Society
https://www.readbyqxmd.com/read/28158961/people-with-chronic-neck-pain-walk-with-a-stiffer-spine
#9
Deborah Falla, Leonardo Gizzi, Hesam Parsa, Angela Dieterich, Frank Petzke
Study Design Case-control. Background People with chronic neck pain present a number of sensorimotor and biomechanical alterations, yet little is known about the influence of neck pain on gait and motions of the spine during gait. Objective To evaluate the spine kinematics and gait characteristics in people with non-specific chronic neck pain. Methods People with chronic non-specific neck pain and age and gender matched asymptomatic controls walked on a treadmill at three different speeds (self-selected, 3km/h, 5km/h) either with their head in a neutral position or rotated 30º...
February 3, 2017: Journal of Orthopaedic and Sports Physical Therapy
https://www.readbyqxmd.com/read/28156207/is-lumbar-facet-fusion-biomechanically-equivalent-to-lumbar-posterolateral-onlay-fusion
#10
Jeffrey M Toth, Kevin T Foley, Mei Wang, Howard B Seim, A Simon Turner
OBJECTIVE This study was designed with the following research objectives: 1) to determine the efficacy of facet fusion with recombinant human bone morphogenetic protein-2 (rhBMP-2) on an absorbable collagen sponge (ACS) in an ovine lumbar facet fusion model; 2) to radiographically and histologically compare the efficacy of lumbar facet fusion with rhBMP-2/ACS to facet fusion with an iliac crest bone graft (ICBG); and 3) to biomechanically compare lumbar facet fusion with rhBMP-2/ACS to lumbar posterolateral fusion (PLF) with ICBG...
February 3, 2017: Journal of Neurosurgery. Spine
https://www.readbyqxmd.com/read/28155678/compression-distraction-reduction-surgical-verification-and-optimization-to-treat-the-basilar-invagination-and-atlantoaxial-dislocation-a-finite-element-analysis
#11
Xuefeng Bo, Weida Wang, Zan Chen, Zhicheng Liu
BACKGROUND: Basilar invagination (BI) combined with atlantoaxial dislocation (AAD) leads to foramen magnum stenosis and medullary spinal cord compression, causing nerve dysfunction. The purpose of the surgery is to remove the bony compression at brainstem ventral side and fix the unstable spinal segment and make it fused stably. Occipital cervical internal fixation system that simultaneously reduces atlantoaxial horizontal and vertical dislocation are established. We propose here a new compression-distraction reduction (CDR) technique...
December 28, 2016: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28155591/impact-of-an-implanted-neuroprosthesis-on-community-ambulation-in-incomplete-sci
#12
Lisa M Lombardo, Rudolf Kobetic, Gilles Pinault, Kevin M Foglyano, Stephanie N Bailey, Stephen Selkirk, Ronald J Triolo
OBJECTIVE: Test the effect of a multi-joint control with implanted electrical stimulation on walking after spinal cord injury (SCI). DESIGN: Single subject research design with repeated measures Setting: Hospital-based biomechanics laboratory and user assessment of community use. PARTICIPANTS: Female with C6 AIS C SCI 30 years post injury. INTERVENTIONS: Lower extremity muscle activation with an implanted pulse generator and gait training...
February 3, 2017: Journal of Spinal Cord Medicine
https://www.readbyqxmd.com/read/28153036/biomechanical-comparison-of-multilevel-lateral-interbody-fusion-with-and-without-supplementary-instrumentation-a-three-dimensional-finite-element-study
#13
Xilin Liu, Jun Ma, Paul Park, Xiaodong Huang, Ning Xie, Xiaojian Ye
BACKGROUND: Lateral lumbar interbody fusion (LLIF) is a popular, minimally invasive technique that is used to address challenging multilevel degenerative spinal diseases. It remains controversial whether supplemental instrumentation should be added for multilevel LLIF. In this study, we compared the kinematic stability afforded by stand-alone lateral cages with those supplemented by bilateral pedicle screws and rods (PSR), unilateral PSR, or lateral plate (LP) fixation using a finite-element (FE) model of a multi-level LLIF construct with simulated osteoporosis...
February 2, 2017: BMC Musculoskeletal Disorders
https://www.readbyqxmd.com/read/28143455/the-association-of-lumbar-curve-magnitude-and-spinal-range-of-motion-in-adolescent-idiopathic-scoliosis-a-cross-sectional-study
#14
Kamil Eyvazov, Dino Samartzis, Jason Pui Yin Cheung
BACKGROUND: Spinal deformities affect the overall alignment of the spine and thus the vectors of loading on the lumbar region and intervertebral discs. Due to wedging of the disc or vertebrae of unbalanced spinal segments, alignment change may affect the range of motion (ROM) of individual spinal segments or the global spine. This is particularly important in adolescent idiopathic scoliosis (AIS) patients who may suffer from early degeneration, back stiffness and pain. Hence, this study aimed to determine the correlation between spine range of motion (ROM) and adolescent idiopathic scoliosis (AIS) curve magnitude...
January 31, 2017: BMC Musculoskeletal Disorders
https://www.readbyqxmd.com/read/28128700/biomechanical-evaluation-of-an-integrated-fixation-cage-during-fatigue-loading-a-human-cadaver-study
#15
Vivek Palepu, Jonathan H Peck, David D Simon, Melvin D Helgeson, Srinidhi Nagaraja
OBJECTIVE Lumbar cages with integrated fixation screws offer a low-profile alternative to a standard cage with anterior supplemental fixation. However, the mechanical stability of integrated fixation cages (IFCs) compared with a cage with anterior plate fixation under fatigue loading has not been investigated. The purpose of this study was to compare the biomechanical stability of a screw-based IFC with a standard cage coupled with that of an anterior plate under fatigue loading. METHODS Eighteen functional spinal units were implanted with either a 4-screw IFC or an anterior plate and cage (AP+C) without integrated fixation...
January 27, 2017: Journal of Neurosurgery. Spine
https://www.readbyqxmd.com/read/28121458/effects-of-practice-variability-on-spinal-manipulation-learning
#16
Andrée-Anne Marchand, Laura Mendoza, Claude Dugas, Martin Descarreaux, Isabelle Pagé
OBJECTIVE: To evaluate the effects of practice variability on chiropractic students' capacity to deliver spinal manipulations (SMs) of a targeted peak force. METHODS: Forty students participated in an experimental session including either a variable or a constant practice protocol of 45 SMs. SMs were delivered on a computer-connected device that recorded force-time profiles. Ten SMs with a target peak force of 350-N were performed before practice, immediately following practice, and 2 days later...
January 25, 2017: Journal of Chiropractic Education
https://www.readbyqxmd.com/read/28117332/animal-models-of-spinal-cord-injury-a-systematic-review
#17
REVIEW
M Sharif-Alhoseini, M Khormali, M Rezaei, M Safdarian, A Hajighadery, M M Khalatbari, M Safdarian, S Meknatkhah, M Rezvan, M Chalangari, P Derakhshan, V Rahimi-Movaghar
STUDY DESIGN: PRISMA-guided systematic review. OBJECTIVES: To provide a comprehensive framework of the current animal models for investigating spinal cord injury (SCI) and categorize them based on the aims, patterns and levels of injury, and outcome measurements as well as animal species. SETTING: Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran. METHODS: An electronic search of the Medline database for literature describing animal models of SCI was performed on 1 January 2016 using the following keywords: 'spinal cord injuries' and 'animal models'...
January 24, 2017: Spinal Cord
https://www.readbyqxmd.com/read/28113132/osseodensification-for-enhancement-of-spinal-surgical-hardware-fixation
#18
Christopher D Lopez, Adham M Alifarag, Andrea Torroni, Nick Tovar, J Rodrigo Diaz-Siso, Lukasz Witek, Eduardo D Rodriguez, Paulo G Coelho
Integration between implant and bone is an essential concept for osseous healing requiring hardware placement. A novel approach to hardware implantation, termed osseodensification, is described here as an effective alternative. 12 sheep averaging 65kg had fixation devices installed in their C2, C3, and C4 vertebral bodies; each device measured 4mm diameter×10mm length. The left-sided vertebral body devices were implanted using regular surgical drilling (R) while the right-sided devices were implanted using osseodensification drilling (OD)...
January 13, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28108403/risk-of-cement-leakage-and-pulmonary-embolism-by-bone-cement-augmented-pedicle-screw-fixation-of-the-thoracolumbar-spine
#19
Insa Janssen, Yu-Mi Ryang, Jens Gempt, Stefanie Bette, Julia Gerhardt, Jan S Kirschke, Bernhard Meyer
BACKGROUND: Cement-augmented pedicle screw instrumentation (CAPSI) of the thoracolumbar spine is indicated in osteoporosis or osteopenia to improve pullout strength and biomechanical stability of pedicle screws (PS). Only a few studies report on the incidence of pulmonary cement embolism or other complications associated with CAPSI. PURPOSE: The aim of this retrospective study was to assess the rate of CAPSI-associated complications. STUDY DESIGN: Retrospective cohort study...
January 17, 2017: Spine Journal: Official Journal of the North American Spine Society
https://www.readbyqxmd.com/read/28107658/validation-of-a-personalized-curved-muscle-model-of-the-lumbar-spine-during-complex-dynamic-exertions
#20
Jaejin Hwang, Gregory G Knapik, Jonathan S Dufour, Thomas M Best, Safdar N Khan, Ehud Mendel, William S Marras
Previous curved muscle models have typically examined their robustness only under simple, single-plane static exertions. In addition, the empirical validation of curved muscle models through an entire lumbar spine has not been fully realized. The objective of this study was to empirically validate a personalized biologically-assisted curved muscle model during complex dynamic exertions. Twelve subjects performed a variety of complex lifting tasks as a function of load weight, load origin, and load height. Both a personalized curved muscle model as well as a straight-line muscle model were used to evaluate the model's fidelity and prediction of three-dimensional spine tissue loads under different lifting conditions...
January 9, 2017: Journal of Electromyography and Kinesiology
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