New methods to study lumbar spine biomechanics: Delineation of in vitro load-displacement characteristics by using a robotic/UFS testing system with hybrid control

2000 ◽  
Vol 10 (4) ◽  
pp. 246-253 ◽  
Author(s):  
Lars G. Gilbertson ◽  
Todd C. Doehring ◽  
James D. Kang
Keyword(s):  
Lumbar Spine ◽  
Hybrid Control ◽  
Testing System ◽  
Spine Biomechanics ◽  
New Methods ◽  
Load Displacement

scholarly journals In vitro spine testing using a robot-based testing system: Comparison of displacement control and “hybrid control”

2013 ◽  
Vol 46 (10) ◽  
pp. 1663-1669 ◽  
Author(s):  
Kevin M. Bell ◽  
Robert A. Hartman ◽  
Lars G. Gilbertson ◽  
James D. Kang
Keyword(s):  
Hybrid Control ◽  
Testing System ◽  
Displacement Control

Variation of Lumbar Spine Stiffness With Load

1987 ◽  
Vol 109 (1) ◽  
pp. 35-42 ◽  
Author(s):  
W. T. Edwards ◽  
W. C. Hayes ◽  
I. Posner ◽  
A. A. White ◽  
R. W. Mann
Keyword(s):  
Lumbar Spine ◽  
Analytical Methods ◽  
Load Testing ◽  
Combined Load ◽  
Combined Loads ◽  
Functional Spinal Unit ◽  
Load Displacement ◽  
Mechanical Studies

Mechanical studies of the Functional Spinal Unit (FSU) in-vitro have shown that the slopes of the load-displacement curves increase with load. This nonlinearity implies that the stiffness of the FSU is not constant over the range of physiologic loads, and that measurements obtained for FSU specimens through the application of individual loads cannot be summed to predict the response of the specimens to combined loads. Both experimental and analytical methods were developed in the present study to better quantify the nonlinear FSU load-displacement response and to calculate the coupled stiffness of FSU specimens at combined states of load reflecting in-vivo conditions. Results referenced to the center of the vertebral body indicate that lumbar FSU specimens are stiffer in flexion than in extension, and that FSU specimens loaded in flexion are stiffer at high loads than at low loads. The importance of combined load testing and a nonlinear interpretation of load-displacement data is demonstrated.

scholarly journals The effect of simulated microgravity on lumbar spine biomechanics: an in vitro study

2015 ◽  
Vol 25 (9) ◽  
pp. 2889-2897 ◽  
Author(s):  
Cory J. Laws ◽  
Britta Berg-Johansen ◽  
Alan R. Hargens ◽  
Jeffrey C. Lotz
Keyword(s):  
Lumbar Spine ◽  
Simulated Microgravity ◽  
In Vitro Study ◽  
Vitro Study ◽  
Spine Biomechanics

The dynamic flexion/extension properties of the lumbar spine in vitro using a novel pendulum system

2007 ◽  
Vol 40 (12) ◽  
pp. 2767-2773 ◽  
Author(s):  
Joseph J. Crisco ◽  
Lindsey Fujita ◽  
David B. Spenciner
Keyword(s):  
Lumbar Spine ◽  
Pendulum System ◽  
Flexion Extension

Effects of Preload on Load Displacement Curves of the Lumbar Spine

1977 ◽  
Vol 8 (1) ◽  
pp. 181-192 ◽  
Author(s):  
Manohar M. Panjabi ◽  
Martin H. Krag ◽  
Augustus A. White ◽  
Wayne O. Southwick
Keyword(s):  
Lumbar Spine ◽  
Load Displacement

Load-Displacement Characteristics of an Implanted Nuclear Pouch in the Lumbar Spine

1999 ◽  
Author(s):  
Andrew P. Dooris ◽  
Nicole M. Grosland ◽  
Vijay K. Goel ◽  
John S. Drake ◽  
James W. Ahern ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Nuclear Space ◽  
Patient Exposure ◽  
Active Joint ◽  
Surgical Morbidity ◽  
Bone Chip ◽  
Spinal Segments ◽  
Load Displacement ◽  
Graft Implantation

Abstract Fusion of the spinal segments is typically done to prevent or correct deformity, stabilize the spine after trauma or pathologic destruction, or eliminate painful movement of the spinal segments. Spinal interbody arthrodesis typically requires considerable patient exposure, necessary for discectomy and graft implantation, and resultant morbidity. Some researchers suggest nuclear replacements as active joint mobilizers, while others suggest full disc replacements, and although some biomechanical consideration has been given, results are unclear. We consider here a device which proposes to reduce surgical morbidity while promoting stability by fusion. The device investigated here is a bone-chip pouch, which fills the nuclear space. We present here initial findings of this device in lumbar cadaveric specimens.

An aniline-substituted bile salt analog protects both mice and hamsters from multiple Clostridioides difficile strains

2021 ◽  
Author(s):  
Jacqueline R. Phan ◽  
Dung M. Do ◽  
Minh Chau Truong ◽  
Connie Ngo ◽  
Julian H. Phan ◽  
...  
Keyword(s):  
Bile Salt ◽  
Spore Germination ◽  
Dependent Manner ◽  
Germination Inhibitors ◽  
New Methods ◽  
Clostridioides Difficile ◽  
Antibiotic Associated Diarrhea ◽  
Careful Screening ◽  
Strain Dependent

Clostridioides difficile infection (CDI) is the major identifiable cause of antibiotic-associated diarrhea. The emergence of hypervirulent C. difficile strains has led to increases in both hospital- and community-acquired CDI. Furthermore, CDI relapse from hypervirulent strains can reach up to 25%. Thus, standard treatments are rendered less effective, making new methods of prevention and treatment more critical. Previously, the bile salt analog CamSA was shown to inhibit spore germination in vitro and protect mice and hamsters from C. difficile strain 630. Here, we show that CamSA was less active at preventing spore germination of other C. difficile ribotypes, including the hypervirulent strain R20291. Strain-specific in vitro germination activity of CamSA correlated with its ability to prevent CDI in mice. Additional bile salt analogs were screened for in vitro germination inhibition activity against strain R20291, and the most active compounds were tested against other strains. An aniline-substituted bile salt analog, (CaPA), was found to be a better anti-germinant than CamSA against eight different C. difficile strains. In addition, CaPA was capable of reducing, delaying, or preventing murine CDI signs in all strains tested. CaPA-treated mice showed no obvious toxicity and showed minor effects on their gut microbiome. CaPA’s efficacy was further confirmed by its ability to prevent CDI in hamsters infected with strain 630. These data suggest that C. difficile spores respond to germination inhibitors in a strain-dependent manner. However, careful screening can identify anti-germinants with broad CDI prophylaxis activity.

Biomechanical in Vitro and Finite Element Study On Different Sagittal Alignment Postures of the Lumbar Spine During Multiaxial Daily Motion

2021 ◽  
Author(s):  
Nadja Wilmanns ◽  
Agnes Beckmann ◽  
Luis Fernando Nicolini ◽  
Christian Herren ◽  
Rolf Sobottke ◽  
...  
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Planning Process ◽  
Axial Rotation ◽  
Intervertebral Discs ◽  
Fe Model ◽  
Bending Moments ◽  
Sagittal Spinal Alignment ◽  
Biomechanical Response

Abstract Lumbar Lordotic correction (LLC), the gold standard treatment for Sagittal Spinal malalignment (SMA), and its effect on sagittal balance have been critically discussed in recent studies. This paper assesses the biomechanical response of the spinal components to LLC as an additional factor for the evaluation of LLC. Human lumbar spines (L2L5) were loaded with combined bending moments in Flexion (Flex)/Extension (Ex) or Lateral Bending (LatBend) and Axial Rotation (AxRot) in a physiological environment. We examined the dependency of AxRot range of motion (RoM) on the applied bending moment. The results were used to validate a Finite Element (FE) model of the lumbar spine. With this model, the biomechanical response of the intervertebral discs (IVD) and facet joints under daily motion was studied for different sagittal spinal alignment (SA) postures, simulated by a motion in Flex/Ex direction. Applied bending moments decreased AxRot RoM significantly (all P<0.001). A stronger decline of AxRot RoM for Ex than for Flex direction was observed (all P<0.0001). Our simulated results largely agreed with the experimental data (all R2>0.79). During daily motion, the IVD was loaded higher with increasing lumbar lordosis (LL) for all evaluated values at L2L3 and L3L4 and posterior Annulus Stress (AS) at L4L5 (all P<0.0476). The results of this study indicate that LLC with large extensions of LL may not always be advantageous regarding the biomechanical loading of the IVD. This finding may be used to improve the planning process of LLC treatments.

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