scholarly journals The contribution of the three columns of the spine to spinal stability: a biomechanical model

Spinal Cord ◽  
1989 ◽  
Vol 27 (6) ◽  
pp. 432-439 ◽  
Author(s):  
T R Haher ◽  
J M Tozzi ◽  
M F Lospinuso ◽  
V Devlin ◽  
M O'Brien ◽  
...  
Keyword(s):  
Biomechanical Model ◽  
Spinal Stability

Acute Traumatic Cervical Facet Fractures

2018 ◽  
Vol 1 (2) ◽  
pp. 5
Author(s):  
Shankar Gopinat
Keyword(s):  
Spinal Cord ◽  
Cervical Spine ◽  
Early Surgery ◽  
Initial Assessment ◽  
Trauma Patients ◽  
Spinal Stability ◽  
Fracture Patterns ◽  
Spine Ct ◽  
Cervical Facet

Acute cervical facet fractures are increasingly being detected due to the use of cervical spine CT imaging in the initial assessment of trauma patients. For displaced cervical facet fractures with dislocations and subluxations, early surgery can decompress the spinal cord and stabilize the spine. For patients with non-displaced cervical facet fractures, the challenge in managing these patients is the determination of spinal stability. Although many of the patients with non-displaced cervical facet fractures can be managed with a cervical collar, the imaging needs to be analyzed carefully since certain fracture patterns may be better managed with early surgical stabilization.

scholarly journals Estimation of Human Center of Mass Position through the Inertial Sensors-Based Methods in Postural Tasks: An Accuracy Evaluation

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 601 ◽  
Author(s):  
Marco Germanotta ◽  
Ilaria Mileti ◽  
Ilaria Conforti ◽  
Zaccaria Del Prete ◽  
Irene Aprile ◽  
...  
Keyword(s):  
Inertial Sensors ◽  
Center Of Mass ◽  
Correlation Coefficients ◽  
Biomechanical Model ◽  
Lower Limbs ◽  
Accuracy Evaluation ◽  
Postural Tasks ◽  
Single Sensor ◽  
Using Data ◽  
Displacement Based

The estimation of the body’s center of mass (CoM) trajectory is typically obtained using force platforms, or optoelectronic systems (OS), bounding the assessment inside a laboratory setting. The use of magneto-inertial measurement units (MIMUs) allows for more ecological evaluations, and previous studies proposed methods based on either a single sensor or a sensors’ network. In this study, we compared the accuracy of two methods based on MIMUs. Body CoM was estimated during six postural tasks performed by 15 healthy subjects, using data collected by a single sensor on the pelvis (Strapdown Integration Method, SDI), and seven sensors on the pelvis and lower limbs (Biomechanical Model, BM). The accuracy of the two methods was compared in terms of RMSE and estimation of posturographic parameters, using an OS as reference. The RMSE of the SDI was lower in tasks with little or no oscillations, while the BM outperformed in tasks with greater CoM displacement. Moreover, higher correlation coefficients were obtained between the posturographic parameters obtained with the BM and the OS. Our findings showed that the estimation of CoM displacement based on MIMU was reasonably accurate, and the use of the inertial sensors network methods should be preferred to estimate the kinematic parameters.

scholarly journals Debridement and corpectomy via single posterior approach to treat pyogenic spondylitis after vertebral augmentation

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Shuai Zhang ◽  
Song Wang ◽  
Qing Wang ◽  
Jin Yang ◽  
Shuang Xu
Keyword(s):  
Severe Pain ◽  
Neurological Deficits ◽  
Spinal Stability ◽  
Vertebral Augmentation ◽  
Pathogenic Microorganisms ◽  
Surgical Time ◽  
Pyogenic Spondylitis ◽  
Single Posterior Approach ◽  
Posterior Debridement ◽  
Effective Treatments

Abstract Background Infection after vertebral augmentation (VA) often limits the daily activities of patients and even threatens their life. The operation may be one of the effective treatments if the patient suffers from intolerable severe pain, neurological deficits, and damage to spinal stability. This study aimed to investigate the clinical efficacy of the treatment of pyogenic spondylitis after vertebral augmentation (PSVA) with Single posterior debridement, vertebral body resection, and intervertebral bone graft fusion and internal fixation (sPVRIF). Methods The study was performed on 19 patients with PSVA who underwent VA at 4 hospitals in the region between January 2010 and July 2020. Nineteen patients were included. Among them, 16 patients underwent sPVRIF to treat the PSVA. Results A total of 2267 patients underwent VA at 4 hospitals in the region. Of the 19 patients with postoperative PSVA, suppurative spondylitis was misdiagnosed as an osteoporotic vertebral fracture(OVF) in 4 patients and they underwent VA. Besides osteoporosis, 18 patients had other comorbidities. The average interval between the first surgery and the diagnosis of PSVA was 96.4 days. Of the 19 patients, 16 received surgical treatment. The surgical time was 175.0±16.8 min, and the intraoperative blood loss was 465.6±166.0 mL. Pathogenic microorganisms were cultured in 12 patients. Conclusion PSVA is a severe complication that can even threaten the life of the patients. sPVRIF may be one of the effective treatments if the patient suffers from intolerable severe pain, neurological deficits, and damage to spinal stability.

Stability as a constraint in sagittal plane human force exertion modeling

1998 ◽  
Vol 1 (1) ◽  
pp. 23-39
Author(s):  
Carter J. Kerk ◽  
Don B. Chaffin ◽  
W. Monroe Keyserling
Keyword(s):  
Muscle Strength ◽  
Ankle Joint ◽  
Coefficient Of Friction ◽  
Sagittal Plane ◽  
Biomechanical Model ◽  
Whole Body ◽  
The Stability ◽  
Joint Center ◽  
Static Conditions ◽  
Stability Limits

The stability constraints of a two-dimensional static human force exertion capability model (2DHFEC) were evaluated with subjects of varying anthropometry and strength capabilities performing manual exertions. The biomechanical model comprehensively estimated human force exertion capability under sagittally symmetric static conditions using constraints from three classes: stability, joint muscle strength, and coefficient of friction. Experimental results showed the concept of stability must be considered with joint muscle strength capability and coefficient of friction in predicting hand force exertion capability. Information was gained concerning foot modeling parameters as they affect whole-body stability. Findings indicated that stability limits should be placed approximately 37 % the ankle joint center to the posterior-most point of the foot and 130 % the distance from the ankle joint center to the maximal medial protuberance (the ball of the foot). 2DHFEC provided improvements over existing models, especially where horizontal push/pull forces create balance concerns.

An index for back pain risk assessment in nursery activities

2005 ◽  
Vol 4 (4) ◽  
pp. 281-290
Author(s):  
Silvia Taloni ◽  
Giovanni Carlo Cassavia ◽  
Giuseppe Luca Ciavarro ◽  
Giuseppe Andreoni ◽  
Giorgio Cesare Santambrogio ◽  
...  
Keyword(s):  
Back Pain ◽  
Biomechanical Model ◽  
Risk Level ◽  
Individual Risk ◽  
Industrialized Countries ◽  
Good Correspondence ◽  
Gold Standard Method ◽  
Trunk Inclination ◽  
Leg Flexion ◽  
The One

Back pain is one of the most significant socioeconomic problem in industrialized countries. Its origin is multifactorial, including physical, psychosocial and individual risk factors. Among the working population, nursery teachers are highly exposed to back pain diseases, but not many studies have dealt with this problem. So a suitable quantitative index is proposed, based on an unobtrusive video-analysis of established motor-tasks. In particular five nursery teachers were asked to perform lifting and lowering movements placing their feet at two different distances from a weight (a toy pet loaded with 8 kg, simulating a child) with different strategies (flexed, partially flexed and extended legs). The index is based on the idea that a greater trunk inclination angle determines increased loads on the lumbar spine, and so an augmented probability of spinal disorders. To validate our protocol, the same data were analyzed through a 3D biomechanical model (gold standard method), which computes the loads on L3-L4 intervertebral disc. Data show a good correspondence between the risk level suggested by the index and the one indicated by the mechanical loads: the antero-posterior shearing forces and the values of index coherently increase with the reduction of leg flexion.

scholarly journals Reduced biomechanical models for precision-cut lung-slice stretching experiments

2021 ◽  
Vol 82 (5) ◽  
Author(s):  
Hannah J. Pybus ◽  
Amanda L. Tatler ◽  
Lowell T. Edgar ◽  
Reuben D. O’Dea ◽  
Bindi S. Brook
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Ex Vivo ◽  
Finite Thickness ◽  
Biomechanical Model ◽  
Local Stress ◽  
Smooth Muscle Contraction ◽  
Biomechanical Models ◽  
Cytokine Activation ◽  
Asymptotic Reduction

AbstractPrecision-cut lung-slices (PCLS), in which viable airways embedded within lung parenchyma are stretched or induced to contract, are a widely used ex vivo assay to investigate bronchoconstriction and, more recently, mechanical activation of pro-remodelling cytokines in asthmatic airways. We develop a nonlinear fibre-reinforced biomechanical model accounting for smooth muscle contraction and extracellular matrix strain-stiffening. Through numerical simulation, we describe the stresses and contractile responses of an airway within a PCLS of finite thickness, exposing the importance of smooth muscle contraction on the local stress state within the airway. We then consider two simplifying limits of the model (a membrane representation and an asymptotic reduction in the thin-PCLS-limit), that permit analytical progress. Comparison against numerical solution of the full problem shows that the asymptotic reduction successfully captures the key elements of the full model behaviour. The more tractable reduced model that we develop is suitable to be employed in investigations to elucidate the time-dependent feedback mechanisms linking airway mechanics and cytokine activation in asthma.

scholarly journals Design, modeling, and demonstration of a new dual-mode back-assist exosuit with extension mechanism

2021 ◽  
Vol 2 ◽  
Author(s):  
Erik P. Lamers ◽  
Karl E. Zelik
Keyword(s):  
Biomechanical Model ◽  
Mode Switching ◽  
Design Parameters ◽  
Dual Mode ◽  
Extension Mechanism ◽  
Body Forces ◽  
Low Profile ◽  
Military Healthcare ◽  
The Moment ◽  
Practical Factors

Abstract Occupational exoskeletons and exosuits have been shown to reduce muscle demands and fatigue for physical tasks relevant to a variety of industries (e.g., logistics, construction, manufacturing, military, healthcare). However, adoption of these devices into the workforce has been slowed by practical factors related to comfort, form-factor, weight, and not interfering with movement or posture. We previously introduced a low-profile, dual-mode exosuit comprised of textile and elastic materials to address these adoption barriers. Here we build upon this prior work by introducing an extension mechanism that increases the moment arm of the exosuit while in engaged mode, then collapses in disengaged mode to retain key benefits related to being lightweight, low-profile, and unobstructive. Here we demonstrate both analytically and empirically how this extensible exosuit concept can (a) reduce device-to-body forces (which can improve comfort for some users and situations), or (b) increase the magnitude of torque assistance about the low back (which may be valuable for heavy-lifting jobs) without increasing shoulder or leg forces relative to the prior form-fitting exosuit. We also introduce a novel mode-switching mechanism, as well as a human-exosuit biomechanical model to elucidate how individual design parameters affect exosuit assistance torque and device-to-body forces. The proof-of-concept prototype, case study, and modeling work provide a foundation for understanding and implementing extensible exosuits for a broad range of applications. We envision promising opportunities to apply this new dual-mode extensible exosuit concept to assist heavy-lifting, to further enhance user comfort, and to address the unique needs of last-mile and other delivery workers.

Biomechanical Model for Detection of Vertigo Disease

2016 ◽  
Author(s):  
Nenad Filipovic ◽  
Zarko Milosevic ◽  
Igor Saveljic ◽  
Dalibor Nikolic ◽  
Nebojsa Zdravkovic ◽  
...  
Keyword(s):  
Biomechanical Model

Non-Newtonian pulsating blood flow-induced dynamic instability of visco-carotid artery within soft surrounding visco-tissue using differential cubature method

2015 ◽  
Vol 229 (16) ◽  
pp. 3002-3012 ◽  
Author(s):  
A Tabatabaie Arani ◽  
Ali Ghorbanpour Arani ◽  
Reza Kolahchi
Keyword(s):  
Blood Flow ◽  
Carotid Arteries ◽  
Shell Theory ◽  
Dynamic Instability ◽  
Current Model ◽  
Biomechanical Model ◽  
Realistic Model ◽  
Instability Region ◽  
Tissue Stiffness ◽  
Voigt Model

The high blood rate that often occurs in carotid arteries may play a role in artery failure and tortuosity which leads to blackouts, transitory ischemic attacks, and other diseases. However, dynamic analysis of carotid arteries conveying blood is lacking. The objective of this study was to present a biomechanical model for dynamic instability analysis of the embedded carotid arteries conveying pulsating blood flow. In order to present a realistic model, the carotid arteries and tissues are assumed viscoelastic using Kelvin–Voigt model. Carotid arteries are modeled as elastic cylindrical vessels based on Mindlin cylindrical shell theory (MCST). One of the main advantages of this study is considering the pulsating non-Newtonian nature of the blood flow using Carreau, Casson, and power law models. Applying energy method, Hamilton’s principle and differential cubature method (DCM), the dynamic instability region (DIR) of the visco-carotid arteries is obtained. The detailed parametric study is conducted, focusing on the combined effects of the elastic medium and non-Newtonian models on the dynamic instability of the visco-carotid arteries. It can be seen that with increasing the tissue stiffness, the natural frequency of visco-carotid arteries decreases. The current model provides a powerful tool for further experimental investigation about arterial tortuosity.

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