Static Traction Research Articles

Age-related differences in the response of the L5-S1 intervertebral disc to spinal traction

BackgroundLumbar traction is a common treatment for low back pain; however its mechanisms of action are poorly understood. It has been hypothesized that a key effect of lumbar traction is its capacity to influence fluid movement within the intervertebral disc (IVD). ObjectivesTo determine differences in the apparent diffusion coefficient (ADC) obtained with lumbar diffusion-weighted imaging (DWI) of the L5-S1 IVD before, and during, the application of lumbar traction. DesignCase series, repeated measures. MethodsA static traction load of ∼50% of body-weight was applied to the low back using a novel “MRI-safe” apparatus. DWI of the lumbar spine was performed prior to, and during the application of the traction load. ResultsParticipants were currently asymptomatic and included a young adult group (n = 18) and a middle-aged group (n = 15). The young adult group had a non-significant 2.2% increase in ADC (mean change = 0.03 × 10−3 mm2/s, SD = 0.24, 95% CI = −0.09, 0.15). The ADC for the middle-aged group significantly increased by 20% (mean change of 0.18 × 10−3 mm2/s, SD = 0.19; 95% CI = 0.07, 0.28; p = 0.003; effect size = 0.95). There was an inverse relationship between the ADC obtained before traction and the percent increase in ADC that was measured during traction. ConclusionStatic traction was associated with an increase in diffusion of water within the L5-S1 IVDs of middle-age individuals, but not in young adults, suggesting age-related differences in the diffusion response. Further study is needed to assess the relationship between these findings and the symptoms of back pain. Level of evidence4.

A scoping review of applications and outcomes of traction orthoses and constructs for the management of intra-articular fractures and fracture dislocations in the hand

IntroductionIntra-articular hand fractures can have devastating consequences for movement and function. The unique nature of the injury and diverse management strategies are a challenge for conducting trials. Purpose of the StudyTo conduct a scoping review of traction constructs for the management of intra-articular hand fractures. MethodsWe conducted a systematic search of the literature, extracting data on the scope and nature of the evidence for traction constructs. ResultsOur search yielded 87 articles addressing 3 traction constructs: (1) static traction (n = 17), (2) dynamic external fixation (n = 53), and (3) dynamic orthoses (n = 17). Active range of motion of the target joint was the most frequently reported outcome. Study designs included 36 cohorts, 21 case series, and 9 case studies: 24% contained only technical information. ConclusionsThe current literature addressing traction constructs consists primarily of small and low-quality studies. Evidence synthesis could improve the estimation of range of motion outcomes but would not be able to identify the best treatment. Consensus on classification of fracture patterns, routine use of outcome measures, and randomized trials are needed to compare different traction constructs and inform evidence-based care. Study designScoping review. Level of evidenceN/A.

Definition of the linearity loss of the surface temperature in static tensile tests

Static traction tests on material samples for mechanical constructions have pointed out the loss of linearity of the specimen surface temperature with the applied load. This phenomenon is due to the heat generation caused by the local microplasticizations which carry the material to deviate from its behavior, perfectly thermoelastic. The identification of the static load which determines the loss of linearity under the temperature stress becomes extremely important to define an initial dynamic characterization of the material. The temperature variations that can be read during the static loads applications are often very limited (a few tenths of degree for every 100 MPa in steels) and they require the use of special temperature sensors able to measure the temperature variations. The experience acquired in such analysis highlighted that, dealing with highly accurate sensors or with particular materials, the identification of the first loss of linearity can be influenced by the investigator himself mainly for the above mentioned limited temperature variations which can lead to incorrect estimations, sometimes really significant. Checking the validity and the above mentioned observations on the different steels, this work proposes the application of the autocorrelation function to the data collected during the application of a static load in order to make the results of the thermal analysis free from the sensitivity of the operator and also to make the result as objective as possible in order to detect the time of the loss of linearity of the temperature-time function.

Determining fatigue limits with thermal analysis of static traction tests

ABSTRACTThis work evaluates the limit stress of the thermo‐elastic phase of deformation by thermo‐analysing the surface of a specimen during a static traction test.By adding a temperature curve measured over a small area of the surface to the classical stress–strain curve, it is possible to evaluate a limit temperature T0 that is coincident with the beginning of the curve's nonlinear trend. The corresponding stress value is as estimation of the fatigue limit of the component under analysis.The authors derive an expression to evaluate temperature during a mono‐axial static traction test. As an example, temperature curves recorded during traction tests performed on two notched steel specimens are reported and compared with this proposed expression. The change to the linearity in the temperature curve during the static traction test is evident in these examples and the corresponding stress value is an estimation of the fatigue limit of the component under analysis.

Alongamento estático versus conceito Mulligan: aplicações no treino de flexibilidade em ginastas

INTRODUÇÃO: Investigar e comparar as adaptações agudas do treino de flexibilidade da articulação coxofemoral no movimento de extensão em atletas de ginástica rítmica, em função de duas técnicas de alongamento: o alongamento estático e a técnica Mulligan - Long Leg Traction. METODOLOGIA:Este é um estudo de caso, de natureza quase-experimental. Participaram do estudo oito atletas do sexo feminino com média de idade de 13,25 anos, divididas em dois grupos. O Grupo 1 foi submetido à técnica Mulligan - Long Leg Traction e o Grupo 2 ao alongamento estático. Utilizou-se a fotogrametria para avaliar a amplitude de movimento de extensão da articulação coxofemoral. Realizou-se a avaliação da amplitude de movimento antes do início do período de treinamento, antes e imediatamente após cada sessão. O protocolo teve duração de seis semanas (11 sessões de treinamento). Utilizou-se estatística descritiva e inferencial para o tratamento dos dados. RESULTADOS: A amplitude de movimento inicial de extensão do quadril foi 31,38º no membro inferior esquerdo e 30,35º no membro inferior direito. Quanto às adaptações agudas ao alongamento, o ganho do Grupo 1 (4,73 ± 0,62º e 4,92 ± 0,26º no membro inferior esquerdo e direito respectivamente) foi estatisticamente superior de modo significativo ao do Grupo 2 (3,42 ± 0,58º no membro inferior esquerdo e 3,5 ± 0,70º no membro inferior direto). CONCLUSÕES: Com relação às adaptações agudas, o Grupo 1 (Mulligan) obteve ganhos estatisticamente significativos superiores que o Grupo 2 (alongamento estático).

Determination of Fatigue Limit by Mono-Axial Tensile Specimens Using Thermal Analysis

In this work is indicated how it could be possible to evaluate the limit stress of the thermo-elastic phase of deformation by thermo-analysing the surface of the specimen during a static traction test. Adding the temperature curve measured on a small area of the surface (the hottest) to the classic stress-strain curve, it is possible to evaluate a limit temperature T0 coincident with the beginning of the non linear trend of the curve. The corresponding stress value is coincident with the fatigue limit of the analyzed component. As an example, the results of traction tests performed on two notched specimens, where the change of linearity in the temperature curve during static traction test was evident, are reported.

Fatigue limit by thermal analysis of specimen surface in mono axial traction test

In this work is indicated how it could be possible to evaluate the limit stress of the thermo-elastic phase of deformation by thermo-analysing the surface of the specimen during a static traction test. Adding the temperature curve measured on a small area of the surface (the hottest) to the classic stress-strain curve, it is possible to evaluate a limit temperature T0 coincident with the beginning of the non linear trend of the curve. The corresponding stress value is coincident with the fatigue limit of the analyzed component. As an example, the results of traction tests performed on two notched specimens, where the change of linearity in the temperature curve during static traction test was evident, are reported. The corresponding value of stress was a good approximation of the fatigue limit for R = - 1, determined by the conventional method. The aim of the reported examples in this paper must be interpreted as support to the basic principle of the method and not as the results of a complete experimental planning of which we will comment in an another occasion.

Comparison of cervical vertebral separation in the supine and seated positions using home traction units

This study was performed for the purpose of comparing the magnitude of cervical vertebral separation during cervical traction in supine and seated positions using home traction units. A repeated measures design with two within-subject factors (type of traction and time) was used. Seventeen asymptomatic volunteers received cervical traction in seated and supine position. Subjects received 5 minutes of static traction in sitting or supine using a force of 13.6 kg while in 15 degrees of neck flexion. A lateral radiograph of the cervical spine was taken before traction force was applied and after five minutes of static traction. Anterior and posterior distances between the inferior border of C2 and the superior border of C7 were measured by a radiologist. After supine traction there were significant increases (p=0.001) in posterior cervical vertebral separation compared to any changes after seated traction. There were no significant changes in anterior vertebral separation during either supine or seated traction positions (p=0.769). Supine cervical traction may be more effective for increasing posterior vertebral separation than seated cervical traction.

Computed tomographic evaluation of lumbar spinal structures during traction

In the previous studies, it is reported that traction diminishes the compressive load on intervertebral discs, reduces herniation, stretches lumbar spinal muscle and ligaments, decreases muscle spasm, and widens intervertebral foramina. The aim of this study was to evaluate the effects of horizontal motorized static traction on spinal anatomic structures (herniated area, spinal canal area, intervertebral disc heights, neural foraminal diameter, and m.psoas diameter) by quantitative measures in patients with lumbar disc herniation (LDH). At the same time the effect of traction in different localizations (median and posterolateral herniation) and at different levels (L4-L5 and L5-S1) was assessed. Thirty two patients with acute LDH participated in the study. A special traction system was used to apply horizontally-motorized static lumbar traction. Before and during traction a CT- scan was made to observe the changes in the area of spinal canal and herniated disc material, in the width of neural foramina, intervertebral disc heights, and in the thickness of psoas muscle. During traction, the area of protruded disc area, and the thickness of psoas muscle decreased 24.5% (p = 0.0001), and 5.7% (p = 0.0001), respectively. The area of the spinal canal and the width of the neural foramen increased 21.6% (p = 0.0001) and 26.7% (p = 0.0001), respectively. The anterior intervertebral disc height remained unchanged with traction however the posterior intervertebral disc height was significantly expanded. This study is the first to evaluated in detail and quantitatively the effect of motorized horizontal lumbar spinal traction on spinal structures and herniated area. According to detailed measures it was concluded that during traction of individuals with acute LDH there was a reduction of the size of the herniation, increased space within the spinal canal, widening of the neural foramina, and decreased thickness of the psoas muscle.

Analytical model of longitudinal tire traction in snow

An analytical model to estimate longitudinal traction of a tire in snow was developed and verified to have good predictability in comparison with measurements. Snow traction of a tire is composed of four kinds of forces in this model: braking force attributable to snow compression, shear force of snow in void (space between tread blocks), frictional force, and digging force (edge effect generated by sipes and blocks). The mechanical characteristics of snow were considered in the prediction of braking force and shear force, but were not considered in the prediction of other forces. The contribution of shear force of snow in void and the frictional force was large in static traction (traction just before a tire slips). On the other hand, the contributions of digging force and frictional force were large in situations involving high slip ratios.

Traction problem in electro-elasticity and bifurcation theory

This paper is the first of a series of two. It will deal with the problem of static traction problem with minor deformations for a material which is governed by the electrostriction phenomenon. Two approaches to this problem will be described. We can consider either the equilibrium equations which are naturally non-linear, or the equations after linearization. The linearization of equations must be done near a natural state. Locally, under some conditions, we can establish the existence and the uniqueness of the solutions. We use the local theorem of implicit functions. The problem can be approached more globally. If we consider the non-linear equations, we can use a natural principle of these equations: the independence of the choice of the observer, also known as objectivity property. This property makes it possible for us to take into account an action of the rotations group of the Euclidean space, and consequently to take into account all the trivial solutions. It is then possible to prove within the space of all configurations the existence of the non-linear equations solutions and to find their number. This work presents a thorough and detailed approach to a non-linear theory, the geometric arguments of which make it possible for us to prove the existence of all the solutions and to study their stability in the aggregate; this last aspect will be developed in the second paper. Not only can this theory anticipate the eventual existence of a stable solution, it can also anticipate that an unstable solution in terms of the elasticity can, thanks to the effect of an electric field, become stable in terms of the electro-elasticity.

Viscoelastic properties of the human lumbodorsal fascia

The purpose of this study is to provide better understanding of the mechanical response of the lumbodorsal fascia to dynamic and static traction loadings. Since the fascia shows a viscoelastic behaviour, tests in which time is a variable were used, namely hysteresis and stress relaxation. Load-strain and load-time curves obtained from the hysteresis and stress-relaxation tests point out three different phenomena. First, an increase in stiffness is noticed when ligaments are successively stretched, i.e. strains produced by successive and identical loads decrease. Second, if a sufficient resting period is allowed between loadings, stiffening is reversed and strains tend to recover initial values. The third phenomenon, observed in stress-relaxation tests as time progresses, is ligament contraction in stretched and isometrically held samples. This third phenomenon may be explained by the possibility that muscle fibres capable of contracting spontaneously could be present in lumbodorsal fascia ligaments.

Cervical Spine Disorders

A randomized clinical trial was conducted to evaluate the efficacy of three commonly employed forms of traction in the treatment of cervical spine disorders. One hundred consenting men and women with disorders of the cervical spine were randomly assigned to one of four treatment groups, static traction, intermittent traction, manual traction, or no traction. All patients, regardless of group assignment, were seen twice weekly. The four groups were shown to be similar with regard to age, sex, diagnosis, chronicity, and prescores on the seven outcome measures. Although the entire cohort of neck patients, regardless of group assignment, improved significantly on all the outcome variables over the 6-week period, patients receiving intermittent traction performed significantly better than those assigned to the no traction group in terms of pain (P = 0.03), forward flexion (P = 0.01), right rotation (P = 0.004) and left rotation (P = 0.05).

On the traction boundary value problem in the linearized gauge theory of dislocations

The static traction boundary value problem for finite material bodies is shown to be well posed in the linearized gauge theory of dislocations. The dislocation field variables assume the roles of generalized stress potentials that satisfy a system of fourth order linear partial differential equations. Accordingly, the stress distributions may be calculated directly from the traction boundary data without solving for the elastic displacement fields. Satisfaction of appropriate gauge conditions are shown to lead to significant simplifications and certain systems of first integrals of the governing equations are exhibited. The important thing here is that the gauge theory of dislocations provides direct means of calculating the distributions of dislocations that arise from given systems of boundary tractions. This is in sharp contrast with previous theories in which the distributions of dislocations are calculated from given distributions of dislocation densities.

Pseudo-radiculopathy in subacute trochanteric bursitis of the subgluteus maximus bursa : R.L. Swezey, Arch. phys. Med., 57 (1976) 387–390

Seventy patients, averaging 82 years of age, were referred for low back pain and/or a suspected herniated disk. Objective neurological deficits consistent with L5 or S1 root involvement were identified in 5 of the 70 patients. Trochanteric bursitis (TB), often mimicking radiculitis, was diagnosed in 31 patients. Trochanteric bursitis was associated with lumbosacral strain and lumbar osteoarthrosis in 21 of 31 patients and with an S1 disk in 1 of those 31 patients. Degenerative joint disease of the ipsilateral hip was present in 4 of 20 of these patients with TB. Six patients with low back pain had both hip and knee arthritis (including two patients with rheumatoid arthritis). Three patients had degenerative hip disease without low back complaints. The remaining patient had TB associated with left hemiparesis. All patients had limitation of lumbosacral motion. Patients with arthritic hips had apparent shortening of the affected leg of one-half inch or greater. Trochanteric bursitis is a common complication of lumbosacral strain, frequently mimicking radiculopathy. Gait alteration associated with back pain or static traction on gluteal musculature during rest therapy may be predisposing factors. The association of TB with hip disease and/or leg length discrepancies was again confirmed.

The balance of energy in earthquake faulting

Summary An earthquake is modelled kinematically by specifying the tangential slip history on a fault surface which expands within a uniformly rotating, self-gravitating, slightly anelastic earth model. The total amount of energy released by such an idealized earthquake is the sum of three distinct quantities: kinetic energy of rotation, gravitational potential energy and thermodynamic elastic internal energy. The first two of these quantities may also be interpreted as the work done throughout the earth model against the action of the apparent centrifugal and real gravitational body forces respectively. The total energy released by an earthquake fault is in general considerably smaller than any of its three individual constituents, since the work performed against body forces is very nearly balanced by the work performed against the initial hydrostatic pressure in the earth model. The smallest individual constituent is the change in the kinetic energy of rotation of the earth model, which may be as much as two orders of magnitude larger than the total energy released, even though the corresponding change in the angular velocity of rotation due to the redistribution of mass is extremely small. The total energy released by an earthquake fault may also be expressed in terms only of the final static displacement and the initial and final static traction on the fault surface itself. This alternative representation of the energy change is explicitly independent of both the rotation and the self-gravitation of the earth model. All of the energy released by an earthquake fault must be dissipated somewhere within the earth model. Energy may be dissipated during faulting either in heating on the walls of the fault surface, where work must generally be done against the action of the frictional traction acting to resist slip, or at the instantaneously expanding boundary of the fault surface, where some energy may be required to overcome cohesion and where there may be additional heating. The remainder of the energy released, which is generally referred to as the seismic energy, is dissipated both during and subsequent to faulting by the slight bodily friction which must be assumed to exist throughout the entire volume of any physically realizable earth model. The seismic energy may also be expressed in terms only of the displacement and incremental traction histories on the instantaneous fault surface during the course of faulting. This alternative representation of the seismic energy is explicitly independent of both the rotation and the self-gravitation of the earth model, and so therefore is the seismic efficiency, which is defined to be the ratio of the seismic energy to the total energy released. Classical formulae for the total energy released by an earthquake fault, the seismic energy and the seismic efficiency are based not only upon the neglect of rotation and self-gravitation, but also upon the assumption that the initial hydrostatic pressure and deviatoric stress are infinitesimal quantities; those classical formulae, upon which many seismological applications depend, are justified if the initial deviatoric stress at the hypocentre is small compared to the hypocentral rigidity.