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PURPOSE: To examine the hypothesis that an increase in response of postmenopausal bone to interval walking training (IWT) depends on baseline bone mineral densities (BMDs). METHODS: Two hundred and thirty-four postmenopausal women (64±5 (SD) yr) with no medication for osteoporosis performed 5-month IWT, repeating fast and slow walking at ≥70% and ~40% peak aerobic capacity, respectively, for 3 minutes each per set, ≥5 sets/day, ≥4 days/week. They were recruited from those who had performed IWT ≥6 months before participating in the study so that their physical fitness and lifestyle-related disease symptoms had almost reached a steady state at the time of their participation. We measured BMDs for the lumbar spine (LS), bilateral femoral neck (FN), and bilateral total hip (TH) by dual-energy X-ray absorptiometry (DXA) before and after the intervention. We used a multiple regression analysis to identify significant independent factors for increasing BMDs after the intervention as baseline physical characteristics, exercise intensity, and exercise time during IWT were the candidates. For any bone site where the independent factor identified was singular, we analyzed the relationship between the identified factor vs increases in BMD after the intervention (ΔBMD) by the locally weighted scatterplot smoothing (LOWESS) method. RESULTS: Almost all subjects completed the designated protocol with minimal adverse events. We found that significant determinants for increasing BMDs were the baseline BMDs for all bone sites, as well as age and body mass index for TH (all, P<0.02). Furthermore, the LOWESS trendline between ΔBMDs vs the baseline BMDs, divided equally into 10 bins for LS and FN, respectively, showed that ΔBMD responses (Y) were attenuated as the baseline BMDs (X) increased in the lower 4 bins and then showed a flat line (Y = ~0) in the remaining higher 6 bins for LS and FN. When the lower 4 bins and the higher 6 bins of the baseline BMD were pooled, respectively, BMDs significantly increased by 1.8% and 1.0% in the lower groups for LS and FN, respectively (both, P<0.001) while not in the higher groups after the intervention (both, P>0.3). CONCLUSIONS: IWT may be of benefit with minimal adverse events to postmenopausal women, although the effects were greater in those with lower baseline BMDs. TRIAL REGISTRATION: UMIN000047428. https://rctportal.niph.go.jp/s/detail/um?trial_id=UMIN000047428#.
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Absorciometría de Fotón , Densidad Ósea , Posmenopausia , Caminata , Humanos , Femenino , Persona de Mediana Edad , Caminata/fisiología , Posmenopausia/fisiología , Anciano , Cuello Femoral/fisiología , Cuello Femoral/diagnóstico por imagen , Osteoporosis Posmenopáusica , Vértebras Lumbares/fisiologíaRESUMEN
Currently, the relationship between axial rotation of the vertebrae and bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) remains controversial. The aim of this study is to quantitatively assess the effect of vertebral rotation on volumetric bone mineral density (v-BMD) and areal bone mineral density (a-BMD), further to propose the corrected strategies. To achieve this, a phantom, which was rotated from 0° to 25° in 5° increments, was utilized. Bone mineral content (BMC), a-BMD, v-BMD, and projected area (p-AREA) were measured. The Kruskal-Wallis non-parametric test or one-way ANOVA was used to examine the differences in variables between the different groups. The Pearson and Spearman correlation was used to test the relationships between quantitative parameters and rotated angles. Linear regression analysis was used to evaluate the relationship between angles and quantitative parameters. The findings indicate that, as the angle increased, a-BMD and v-BMD decreased (P < 0.001) , and the p-AREA increased (P < 0.001), but the BMC stays constant. The rotated angle was negative correlated (r = - 0.925, P < 0.001) with a-BMD and v-BMD (r = - 0.880, P < 0.001), positive (r = 0.930, P = < 0.001) correlated with p-AREA. The linear regression analysis showed that a-BMD = 0.808-0.01 × Angle and v-BMD = 151.808-1.588 × Angle. This study showed that, axial rotation might lead to a lower measured for a-BMD and v-BMD, it should be modified. This gives clinicians some insights into how to deal with osteoporosis in scoliosis patients. It's essential for clinicians to incorporate these findings into their diagnostic processes to prevent potential misdiagnosis and over-treatment of osteoporosis.
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Absorciometría de Fotón , Densidad Ósea , Vértebras Lumbares , Tomografía Computarizada por Rayos X , Humanos , Vértebras Lumbares/diagnóstico por imagen , Vértebras Lumbares/fisiología , Tomografía Computarizada por Rayos X/métodos , Rotación , Fantasmas de ImagenRESUMEN
BACKGROUND: There is limited research providing an overall understanding of bone mineral density (BMD) changes throughout different stages of life. This study aimed to investigate the pattern of BMD changes across childhood, adolescence, adulthood, and old age, as well as exploring the critical time of peak BMD (PBMD). METHODS: Participants of three major ethnicities from National Health and Nutrition Examination Survey 1999 to 2018 were involved: 46,381 and 20,944 participants aged 8-85 years old were included in the Lumbar spine BMD (LSBMD) and femoral neck BMD (FNBMD) studies, respectively. BMD was measured using dual-energy X-ray absorptiometry. The generalized additive model was used to construct smoothed percentile curves. RESULTS: Both males and females experienced a sharp increase in LSBMD during puberty, with females reaching their PBMD earlier than males. Females' LSBMD remained higher than males' before the age of approximately 50, except for Non-Hispanic Blacks. For males, LSBMD reached a plateau at around 30 years old after reaching the peak value. Females exhibited two peak points on the fitted curves, with the second PBMD occurring around 36-37 years old. Ethnic variations were observed, with Non-Hispanic Blacks displaying the highest BMD levels at all ages. Non-Hispanic Whites and Mexican Americans had lower BMD levels, with Mexican Americans generally exhibiting the lowest BMD. FNBMD reached its peak earlier than LSBMD, and males consistently had higher FNBMD than females. CONCLUSIONS: This nationally representative study contributes to the understanding of BMD changes across the lifespan, and might provide guidance for bone health interventions in different population groups.
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Absorciometría de Fotón , Densidad Ósea , Encuestas Nutricionales , Humanos , Femenino , Masculino , Niño , Adolescente , Persona de Mediana Edad , Adulto , Anciano , Adulto Joven , Anciano de 80 o más Años , Vértebras Lumbares/fisiología , Cuello Femoral , Estados Unidos , LongevidadRESUMEN
The purpose of the study was to determine whether running is associated with greater bone mineral density (BMD) by comparing the BMD of regularly active male runners (AR) with inactive nonrunner male controls (INC). This cross-sectional study recruited 327 male AR and 212 male INC (aged 18-65) via a stratified recruitment strategy. BMD of the whole body (WB) and partial segments (spine, lumbar spine (LS), leg, hip, femoral neck (FN), and arm for each side) were measured by dual-energy x-ray absorptiometry (DXA) and lower leg dominance (dominant-D/nondominant-ND) was established by functional testing. An ANCOVA was used to compare AR and INC. The AR had greater BMD for all segments of the lower limb (p<0.05), but similar BMD for all segments of the upper limb (p>0.05) compared with INC. Based on the pairwise comparison of age groups, AR had greater BMD of the ND leg in every age group compared with INC (p<0.05). AR had grater BMD of the D leg in every age group except for (26-35 and 56-65) compare with INC (p<0.05). In the youngest age group (18-25), AR had greater BMD in every measured part of lower extremities (legs, hips, femoral necks) compared with INC (p<0.05). In the 46-55 age group AR had greater BMD than INC (p < 0.05) only in the WB, D Leg, D neck, and ND leg. In the 56-65 age group AR had greater BMD than INC (p<0.05) only in the ND leg. Overall, AR had greater BMD compared with INC in all examined sites except for the upper limbs, supporting the notion that running may positively affect bone parameters. However, the benefits differ in the skeletal sites specifically, as the legs had the highest BMD difference between AR and INC. Moreover, the increase in BMD from running decreased with age.
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Absorciometría de Fotón , Densidad Ósea , Carrera , Humanos , Masculino , Densidad Ósea/fisiología , Estudios Transversales , Persona de Mediana Edad , Adulto , Carrera/fisiología , Anciano , Adolescente , Adulto Joven , Cuello Femoral/diagnóstico por imagen , Cuello Femoral/fisiología , Vértebras Lumbares/fisiología , Vértebras Lumbares/diagnóstico por imagenRESUMEN
OBJECTIVE: The relationship between body fat mass and bone mineral density (BMD) remains controversial. This research aimed to explore the linear or non-linear relationship between body fat mass and BMD among adults in the United States. METHODS: This cross-sectional study identified adults aged 18 years or older in the National Health and Nutrition Examination Survey from 2011 to 2018. After adjusting for covariates, linear relationships between body fat mass and BMD in different genders were tested by generalized linear models, and potential non-linear relationships were explored by generalized additive models and piecewise linear regression models. RESULTS: The research included 4691 (57.9% of the total sample) males and 3417 (42.1% the of total sample) females. In both males and females, we found a negative association between android or total body fat mass and lumbar spine BMD and a positive association between appendicular, android, gynoid, or total body fat mass and whole body BMD (all P < 0.05). The relationships between body fat mass in all regions and lumbar spine BMD were U-shaped in males and inverted U-shaped in females (all Pnon-linear < 0.05). Inverted U-shaped relationships existed between body fat mass in all regions and whole body BMD in females (all Pnon-linear < 0.05). CONCLUSIONS: Body fat mass was negatively and linearly associated with lumbar spine BMD, but positively associated with whole body BMD. Body fat mass had a U-shaped relationship with lumbar spine BMD in males and an inverted U-shaped association with lumbar spine and whole body BMD in females.
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Densidad Ósea , Encuestas Nutricionales , Humanos , Masculino , Femenino , Densidad Ósea/fisiología , Estudios Transversales , Persona de Mediana Edad , Adulto , Estados Unidos , Distribución de la Grasa Corporal , Vértebras Lumbares/fisiología , Anciano , Tejido AdiposoRESUMEN
BACKGROUND: To better personalize treatment and monitor recovery of individuals with low back pain, objective tests of sensorimotor functions, such as lumbar proprioception, must be selected based on their reliability and validity. The primary objective of this study was to test the concurrent validity of three measures of lumbar proprioception. METHODS: Thirty-one participants performed three lumbar proprioception tests (motion perception threshold, active and passive joint positioning sense), a whole-body mobility and balance (time up-and-go) and two trunk-specific postural control (threshold of stability and sensor-based sway measures) tests. RESULTS: Only the motion perception threshold proprioception test showed some validity, correlating with the trunk-specific postural control tests [r range (positive values): 0.37 to 0.60]. The three lumbar proprioception measures were not correlated to each other. The threshold of stability measure was correlated with the time up-and-go (r = 0.37) and trunk-specific (sensor-based sway measures) postural control [r range (positive values): 0.48 to 0.77] tests. CONCLUSION: The present study generated three original findings. Only the motion perception threshold proprioception test demonstrated its concurrent validity. In fact, the three lumbar proprioception tests performed in the present study were not correlated to each other, thus assessing different constructs. Finally, the threshold of stability protocol was validated against other tests. These findings will help in selecting the most appropriate lumbar proprioception measures to study the effects of exercise treatments in patients with back pain.
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Vértebras Lumbares , Equilibrio Postural , Propiocepción , Humanos , Propiocepción/fisiología , Masculino , Femenino , Vértebras Lumbares/fisiología , Reproducibilidad de los Resultados , Equilibrio Postural/fisiología , Adulto , Percepción de Movimiento/fisiologíaRESUMEN
INTRODUCTION: Uncertainty exists regarding the best method for teaching thrust joint manipulation (TJM) to student physical therapists. The purpose of this study was to compare the effectiveness of Peyton's 4-step (P4) approach with the "see one, do one" (S1D1) approach for teaching students to perform a lumbar spine TJM task in an academic setting. Secondary objectives were to compare the effects of each instructional approach on students' attitudes and beliefs toward spinal TJM and on their motivation to learn to perform lumbar spine TJM. REVIEW OF LITERATURE: The S1D1 approach is used in the health care professions for teaching clinical tasks to students. It is unclear whether the P4 approach may better prepare students to practice TJM. SUBJECTS: Student physical therapists. METHODS: Using a factorial quasi-experimental design, an equal number of students were assigned to a P4 or S1D1 instruction group for the TJM task. Students' performance accuracy, time, and outcome performing TJM in an academic setting were measured. Paper surveys were used to collect data about students' attitudes and beliefs toward spinal TJM and their motivation to learn TJM. A generalized estimating equations approach was used for data analysis. RESULTS: Fifty-eight students (29 per group) completed the study. There was an interaction between the instruction group and time on task performance accuracy favoring the P4 approach (P = .03). There was no interaction between the instruction group and task performance time, task performance outcome, attitudes and beliefs toward spinal TJM, or motivation to learn TJM (all P > .19). DISCUSSION AND CONCLUSION: The P4 approach more effectively improved student accuracy when performing the TJM task in an academic setting than the S1D1 approach. However, no differences between instruction were found for performance time or outcome. Students reported a favorable perception of learning lumbar spine TJM. These preliminary results suggest that instructors may use the P4 approach to improve students' TJM procedural knowledge before task practice. However, limitations of the study may affect the internal validity and generalizability of results.
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Manipulación Espinal , Humanos , Femenino , Masculino , Manipulación Espinal/métodos , Vértebras Lumbares/fisiología , Análisis y Desempeño de Tareas , Motivación , Competencia Clínica , Fisioterapeutas/educación , Enseñanza , Adulto , Adulto JovenRESUMEN
INTRODUCTION: Clinical investigations have attributed lumbar spine injuries in combat to the vertical vector. Injury prevention strategies include the determination of spine biomechanics under this vector and developing/evaluating physical devices for use in live fire and evaluation-type tests to enhance Warfighter safety. While biological models have replicated theater injuries in the laboratory, matched-pair tests with physical devices are needed for standardized tests. The objective of this investigation is to determine the responses of the widely used Hybrid III lumbar spine under the vertical impact-loading vector. MATERIALS AND METHODS: Our custom vertical accelerator device was used in the study. The manikin spinal column was mounted between the inferior and superior six-axis load cells, and the impact was delivered to the inferior end. The first group of tests consisted of matched-pair repeatability tests, second group consisted of adding matched-pair tests to this first group to determine the response characteristics, and the third group consisted of repeating the earlier two groups by changing the effective torso mass from 12 to 16 kg. Peak axial, shear, and resultant forces at the two ends of the spine were obtained. RESULTS: The first group of 12 repeatability tests showed that the mean difference in the axial force between two tests at the same velocity across the entire range of inputs was <3% at both ends. In the second group, at the inferior end, the axial and shear forces ranged from 4.9-25.2 kN to 0.7-3.0 kN. Shear forces accounted for a mean of 11 ± 6% and 12 ± 4% of axial forces at the two ends. In the third group of tests with increased torso mass, repeatability tests showed that the mean difference in the axial force between the two tests at the same velocity across the entire range of inputs was <2% at both ends. At the inferior end, the axial and shear forces ranged from 5.7-28.7 kN to 0.6-3.4 kN. Shear forces accounted for a mean of 11 ± 8% and 9 ± 3% of axial forces across all tests at the inferior and superior ends. Other data including plots of axial and shear forces at the superior and inferior ends across tested velocities of the spine are given in the paper. CONCLUSIONS: The Hybrid III lumbar spine when subjected to vertical impact simulating underbody blast levels showed that the impact is transmitted via the axial loading mechanism. This finding paralleled the results of axial force predominance over shear forces and axial loading injuries to human spines. Axial forces increased with increasing velocity suggesting the possibility of developing injury assessment risk curves, i.e., the manikin spine does not saturate, and its response is not a step function. It is possible to associate probability values for different force magnitudes. A similar conclusion was found to be true for both magnitudes of added effective torso mass at the superior end of the manikin spinal column. Additional matched-pair tests are needed to develop injury criteria for the Hybrid III male and female lumbar spines.
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Vértebras Lumbares , Maniquíes , Humanos , Vértebras Lumbares/fisiología , Fenómenos Biomecánicos/fisiología , Soporte de Peso/fisiologíaRESUMEN
The objective of the study is to investigate the vibration behavior of the entire spine inside the human body and the influence of muscle soft tissue and lower limbs on spinal response under vertical whole-body vibration. This study conducted modal and random response analyses to simulate the modal displacements and stress of all intervertebral discs in the vertical principal mode in the skeleton, upper, and whole body. Additionally, the acceleration response of intervertebral discs under vertical random excitation was investigated. The results revealed that removing muscle soft tissue and lower limbs significantly changed the resonant frequency, modal displacement, and stress. Particularly, there was a rapid increase in vertical displacement of the lumbar spine in the skeleton model. The reason for that was due to the lack of soft tissue to provide stability, leading to significant lumbar spine bending. Under random excitation, the fore-aft acceleration of intervertebral discs in the skeleton model was considerably larger than that in the whole body, especially in the lumbar spine where it can reach up to four times higher. Conversely, the vertical response of the intervertebral discs inside the human body model was 1.4-2.4 times larger than that of the skeleton model. Muscle soft tissue contributes to the strength of the spine, reducing fore-aft response. The muscle soft tissue in the gluteal region, connected below the spine, can lower the vertical natural frequency and attenuate spinal impact. Although the lower limbs enhance spinal stability, stimulation from the feet can superimpose vibrational responses in the spine.
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Análisis de Elementos Finitos , Extremidad Inferior , Vibración , Humanos , Extremidad Inferior/fisiología , Columna Vertebral/fisiología , Fenómenos Biomecánicos , Sedestación , Músculos/fisiología , Músculo Esquelético/fisiología , Disco Intervertebral/fisiología , Estrés Mecánico , Vértebras Lumbares/fisiologíaRESUMEN
Modeling the lumbar facet capsular ligament's (FCL) mechanical behavior under various physiological motions has often been a challenge due to limited knowledge about the on-joint in situ ligament state arising from attachment to the bone or other internal loads. Building on prior work, this study presents an enhanced computational model of the lumbar facet capsular ligament by incorporating residual strain and joint pressurization strain, factors neglected in prior models. Further, the model can predict strain and stress distribution across the ligament under various spinal motions, highlighting the influence of the ligament's attachment to the bone, internal synovial fluid pressurization, and distribution of collagen fiber alignment on the overall mechanical response of the ligament. Joint space inflation was found to influence the total observed stress and strain fields, both at rest and during motion. A significant portion of the ligament was found to be in tension, even in the absence of external load. Additionally, the model's ability to account for residual strain offers a more realistic portrayal of the collagen fibers and elastin matrix's role in ligament mechanics. We conclude that (1) computational models of the lumbar facet capsular ligament should not assume that the ligament is unloaded when the joint is in its neutral position, and (2) the ligament is nearly always in tension, which may be important in terms of its long-term growth and remodeling.
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Colágeno , Vértebras Lumbares , Estrés Mecánico , Vértebras Lumbares/fisiología , Colágeno/metabolismo , Articulación Cigapofisaria/fisiología , Fenómenos Biomecánicos , Ligamentos/fisiología , Presión , Ligamentos Articulares/fisiología , Humanos , Análisis de Elementos Finitos , Modelos Biológicos , Soporte de PesoRESUMEN
Work-related musculoskeletal disorders are a major health issue, but there is little research to show whether active lumbar exoskeletons are suitable for single-shoulder load. The purpose of this study was to identify the effect of wearable lumbar support exoskeleton with single-shoulder load on movement of the lumbar and thoracic spine and plantar pressure. The experiment was conducted considering ten healthy male young adults. Data about three-dimensional motion angles of the lumbar and thoracic spine, as well as plantar pressure, were collected in the control condition (0% of body weight: 0% BW), experimental condition A (single-shoulder load: 5% BW and 10% BW), and experimental condition B (single-shoulder load and left lateral traction: 5% BW-T and 10% BW-T). The two-way repeated measures analysis of variance (ANOVA) was conducted with device and weight as within subject factors. The level of statistical significance was set at p<0.05. In experimental condition A, significant difference observed in the lumbar and thoracic flexion angle compared to 0% BW (all p<0.05). the plantar pressure information was affected by the single-shoulder load especially about plantar pressure. In experimental condition B, there were no significant differences on the all values of lumbar and thoracic angles other than the ROM value of thoracic rotation angle in 5% BW-T and 10% BW-T (p = 0.0082 and p = 0.0056). Furthermore, the COP of the subject was symmetrical in experimental condition B, the peak force increased compared to 0% BW but less than the single-shoulder load. The WLSE provided a possibility for protecting and preventing the human lumbar and thorax in single-shoulder load.
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Dispositivo Exoesqueleto , Vértebras Lumbares , Presión , Hombro , Torso , Dispositivos Electrónicos Vestibles , Soporte de Peso , Humanos , Masculino , Adulto Joven , Soporte de Peso/fisiología , Hombro/fisiología , Fenómenos Biomecánicos , Adulto , Torso/fisiología , Vértebras Lumbares/fisiología , Voluntarios Sanos , Pie/fisiología , Rango del Movimiento Articular/fisiología , Movimiento/fisiología , Vértebras Torácicas/fisiologíaRESUMEN
Lower back disorders (LBDs) affect a large proportion of the population, and treatment for LBDs have been shifting toward individualized, patient-centered approaches. LBDs are typically associated with poor proprioception. Therefore, there has been a recent uptake in the utilization of wearable sensors that can administer biofeedback in various industrial, clinical, and performance-based settings to improve lumbar proprioception. The aim of this study was to investigate whether wearable sensor-derived acute auditory biofeedback can be used to improve measures of gross lumbar proprioception. To assess this, healthy participants completed an active target repositioning protocol, followed by a training period where lumbar-spine posture referenced auditory feedback was provided for select targets. Target re-matching abilities were captured before and after acute auditory biofeedback training to extract measures related to accuracy and precision across spine flexion targets (i.e., 20%, 40%, 60%, 80% maximum). Results suggest a heterogenous response to proprioceptive training whereby certain individuals and spine flexion targets experienced positive effects (i.e., improved accuracy and precision). Specifically, results suggest that mid-range flexion targets (i.e., 40-60% maximum flexion) benefited most from the acute auditory feedback training. Further, individuals with poorer repositioning abilities in the pre-training assessment showed the greatest improvements from the auditory feedback training.
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Biorretroalimentación Psicológica , Propiocepción , Dispositivos Electrónicos Vestibles , Humanos , Propiocepción/fisiología , Masculino , Biorretroalimentación Psicológica/métodos , Biorretroalimentación Psicológica/fisiología , Biorretroalimentación Psicológica/instrumentación , Femenino , Adulto , Adulto Joven , Región Lumbosacra/fisiología , Retroalimentación Sensorial/fisiología , Vértebras Lumbares/fisiologíaRESUMEN
BACKGROUND: This study aimed to evaluate the effect of foraminoplasty using large-channel endoscopy during TESSYS on the biomechanics of the lumbar spine. METHODS: A complete lumbar spine model, M1, was built using 3D finite elements, and models M2 and M3 were constructed to simulate the intraoperative removal of the superior articular process of L5 using a trephine saw with diameters of 5 mm and 8.5 mm, respectively, and applying normal physiological loads on the different models to simulate six working conditions-anterior flexion, posterior extension, left-right lateral bending, and left-right rotation-to investigate the displacement and facet joint stress change of the surgical segment, and the disc stress change of the surgical and adjacent segments. RESULTS: Compared with the M1 model, the M2 and M3 models showed decreased stress at the L4-5 left FJ and a significant increase in stress at the right FJ in forward flexion. In the M2 and M3 models, the L4-5 FJ stresses were significantly greater in left lateral bending or left rotation than in right lateral bending or right rotation. The right FJ stress in M3 was greater during left rotation than that in M2, and that in M2 was greater than that in M1. The L4-5disc stress in the M3 model was greater during posterior extension than that in the M1 and M2 models. The L4-5disc stress in the M3 model was greater in the right rotation than in the M2 model, and that in the M2 model was greater than that in the M1 model. CONCLUSION: Foraminoplasty using large-channel endoscopy could increase the stress on the FJ and disc of the surgical segment, which suggested unnecessary and excessive resection should be avoided in PTED to minimize biomechanical disruption.
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Discectomía Percutánea , Endoscopía , Análisis de Elementos Finitos , Vértebras Lumbares , Humanos , Vértebras Lumbares/cirugía , Vértebras Lumbares/fisiología , Fenómenos Biomecánicos , Discectomía Percutánea/métodos , Endoscopía/métodos , Foraminotomía/métodos , Modelos Anatómicos , Estrés MecánicoRESUMEN
Lumbar spine injuries resulting from heavy or repetitive lifting remain a prevalent concern in workplaces. Back-support devices have been developed to mitigate these injuries by aiding workers during lifting tasks. However, existing devices often fall short in providing multidimensional force assistance for asymmetric lifting, an essential feature for practical workplace use. In addition, validation of device safety across the entire human spine has been lacking. This paper introduces the Bilateral Back Extensor Exosuit (BBEX), a robotic back-support device designed to address both functionality and safety concerns. The design of the BBEX draws inspiration from the anatomical characteristics of the human spine and back extensor muscles. Using a multi-degree-of-freedom architecture and serially connected linear actuators, the device's components are strategically arranged to closely mimic the biomechanics of the human spine and back extensor muscles. To establish the efficacy and safety of the BBEX, a series of experiments with human participants was conducted. Eleven healthy male participants engaged in symmetric and asymmetric lifting tasks while wearing the BBEX. The results confirm the ability of the BBEX to provide effective multidimensional force assistance. Moreover, comprehensive safety validation was achieved through analyses of muscle fatigue in the upper and the lower erector spinae muscles, as well as mechanical loading on spinal joints during both lifting scenarios. By seamlessly integrating functionality inspired by human biomechanics with a focus on safety, this study offers a promising solution to address the persistent challenge of preventing lumbar spine injuries in demanding work environments.
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Músculos de la Espalda , Diseño de Equipo , Elevación , Humanos , Masculino , Fenómenos Biomecánicos , Adulto , Elevación/efectos adversos , Músculos de la Espalda/fisiología , Traumatismos Vertebrales/prevención & control , Adulto Joven , Robótica/instrumentación , Dispositivo Exoesqueleto , Vértebras Lumbares/fisiología , Vértebras Lumbares/lesiones , Columna Vertebral/fisiología , Columna Vertebral/anatomía & histología , ElectromiografíaRESUMEN
Background and Objectives: Osteoporosis renders the use of traditional interbody cages potentially dangerous given the high risk of damage in the bone-implant interface. Instead, injected cement spacers can be applied as interbody devices; however, this technique has been mainly used in cervical spine surgery. This study aimed at investigating the biomechanical behavior of cement spacers versus traditional cages in lumbar spine surgery. Materials and Methods: Destructive monotonic axial compression testing was performed on 20 human cadaveric low-density lumbar segments from elderly donors (14 f/6 m, 70.3 ± 12.0 y) treated with either injected cement spacers (n = 10) or traditional cages (n = 10) without posterior instrumentation. Stiffness, failure load and displacement were compared. The effects of bone density, vertebral geometry and spacer contact area were evaluated. Results: Cement spacers demonstrated higher stiffness, significantly smaller displacement (p < 0.001) and a similar failure load compared to traditional cages. In the cage group, stiffness and failure load depended strongly on bone density and vertebral height, whereas failure displacement depended on vertebral anterior height. No such correlations were identified with cement spacers. Conclusions: Cement spacers used in lumbar interbody stabilization provided similar compression strength, significantly smaller failure displacement and a stiffer construct than traditional cages that provided benefits mainly for large and strong vertebrae. Cement stabilization was less sensitive to density and could be more beneficial also for segments with smaller and less dense vertebrae. In contrast to the injection of cement spacers, the optimal insertion of cages into the irregular intervertebral space is challenging and risks damaging bone. Further studies are required to corroborate these findings and the treatment selection thresholds.
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Cementos para Huesos , Cadáver , Vértebras Lumbares , Humanos , Vértebras Lumbares/cirugía , Vértebras Lumbares/fisiología , Fenómenos Biomecánicos , Cementos para Huesos/uso terapéutico , Masculino , Anciano , Femenino , Persona de Mediana Edad , Anciano de 80 o más Años , Densidad Ósea , Fuerza Compresiva , Soporte de Peso/fisiología , OsteoporosisRESUMEN
BACKGROUND This study aimed to evaluate the effect of standing and sitting positions on spinal curvatures evaluated using projection moire and muscle tone and stiffness using the MyotonPRO hand-held device in young women. MATERIAL AND METHODS Thirty-three healthy women, aged 21 to 23 years, volunteered in the study. We used the projection moire method to examine spinal curvatures in both positions and the MyotonPRO device to measure the tone and stiffness of muscles in 3 regions. We evaluated the effects of positions (standing vs sitting), regions (cervical, thoracic, and lumbar), and side factor (right vs left) using multivariate analysis. RESULTS The sitting position significantly decreased the lumbosacral and thoracolumbar angles (P<0.001), but had no effect on the superior thoracic angle. Muscle tension and stiffness were the highest (P<0.001) in the cervical region and did not differ between positions (P>0.05) in this region. We found significantly higher muscle tone and stiffness in the thoracic and lumbar regions during sitting than during standing (P<0.001). There was symmetry in the muscle tone and the stiffness between the right and left sides of the spine. CONCLUSIONS The sitting posture decreased lumbosacral and thoracolumbar angles but increased muscle tension and stiffness in the lumbar and thoracic regions only. The symmetry of muscle tone and transverse stiffness in both positions was the normative value. This study provides insight into the adaptive physiological changes in spinal curvature and muscle mechanical properties in young women and serves as an important reference point for clinical studies of women.
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Sedestación , Curvaturas de la Columna Vertebral , Posición de Pie , Humanos , Femenino , Adulto Joven , Curvaturas de la Columna Vertebral/fisiopatología , Fotogrametría/métodos , Postura/fisiología , Columna Vertebral/fisiología , Músculo Esquelético/fisiología , Adulto , Tono Muscular/fisiología , Fenómenos Biomecánicos/fisiología , Vértebras Lumbares/fisiologíaRESUMEN
INTRODUCTION: Lumbar range of motion (ROM) is a critical component of spinal function and often affected by age and sex. This study aimed to evaluate the variations in lumbar ROM across different age groups in a healthy adult population and determine the influence of sex, height, weight, and body mass index. METHODS: A total of 208 subjects (106 men, 102 women) were recruited and stratified into age groups from the 20s to 60s and older. Lumbar ROM was measured using the Wolfson modified Schober test. Data were analyzed for flexion, extension, and total ROM. Linear regression examined the predictors of lumbar ROM. RESULTS: The study found a progressive decline in lumbar flexion and total ROM with age. Age was the only notable predictor of lumbar flexion, with no notable effect of weight and body mass index on ROM. Extension measurements were inconsistent and did not show a clear pattern across age groups. DISCUSSION: Age-related changes in lumbar ROM were consistent with known physiological changes within the spine. Despite physical differences in height and weight, the lumbar spine ROM was similar between sexes, highlighting the influence of age over sex in lumbar motion. Lumbar ROM decreases with age, with flexion affected more than extension.
Asunto(s)
Vértebras Lumbares , Rango del Movimiento Articular , Humanos , Masculino , Femenino , Rango del Movimiento Articular/fisiología , Persona de Mediana Edad , Adulto , Vértebras Lumbares/fisiología , Anciano , Adulto Joven , Factores de Edad , Índice de Masa Corporal , Factores Sexuales , Examen Físico/métodosRESUMEN
During forward flexion, spine motion varies due to age and sex differences. Previous studies showed that lumbar/pelvis range of flexion (RoF) and lumbo-pelvic ratio (L/P) are age/sex dependent. How variation of these parameters affects lumbar loading in a normal population requires further assessment. We aimed to estimate lumbar loads during dynamic flexion-return cycle and the differences in peak loads (compression) and corresponding trunk inclinations due to variation in lumbar/pelvis RoF and L/P. Based on in vivo L/P (0.11-3.44), temporal phases of flexion (early, middle, and later), the lumbar (45-55°) and hip (60-79°) RoF; full flexion-return cycles of six seconds were reconstructed for three age groups (20-35, 36-50 and 50+ yrs.) in both sexes. Six inverse dynamic analyses were performed with a 50th percentile model, and differences in peak loads and corresponding trunk inclinations were calculated. Peak loads at L4-L5 were 179 N higher in younger males versus females, but 228 N and 210 N lower in middle-aged and older males, respectively, compared to females. Females exhibited higher trunk inclinations (6°-20°) than males across all age groups. Age related differences in L4-L5 peak loads and corresponding trunk inclinations were found up to 415 N and 19° in males and 152 N and 13° in females. With aging, peak loads were reduced in males but were found non-monotonic in females, whereas trunk inclinations at peak loads were reduced in both sexes from young to middle/old age groups. In conclusion, lumbar loading and corresponding trunk inclinations varied notably due to age/sex differences. Such data may help distinguishing normal or pathological condition of the lumbar spine.
Asunto(s)
Vértebras Lumbares , Soporte de Peso , Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Vértebras Lumbares/fisiología , Soporte de Peso/fisiología , Posición de Pie , Rango del Movimiento Articular/fisiología , Modelos Biológicos , Fenómenos Biomecánicos , Factores de Edad , Caracteres Sexuales , Postura/fisiología , Adulto Joven , Envejecimiento/fisiología , Columna Vertebral/fisiología , Pelvis/fisiologíaRESUMEN
The kinetic demands of the spine can be assessed using a top-down (TD) or bottom-up (BU) approach, which start calculations from the either the hands or from the feet, respectively. Biomechanists have traditionally favored a BU approach, though existing modeling approaches encourage a TD approach. Regardless of the approach the demands should be similar, provided the external forces and linked segment parameters are equivalently measured and modeled. Demonstrating a level of agreement between the two approaches can help evaluate a model. Further, having both approaches can be advantageous when data is inaccurate or unavailable for one. The purpose of this study was to compare the internal moments and forces at multiple lumbar and thoracic intervertebral joint (IVJ) levels during lifting tasks from an established OpenSim thoracolumbar spine model that applies a TD approach and a similar model modified to adopt a BU approach. Kinematics and external forces were recorded from twelve participants during sagittal and lateral lifts of different lifting speeds and crate masses. For both approaches IVJ kinetics were estimated using a standard OpenSim modeling pipeline. The BU and TD approach IVJ joint moments generally agreed both temporally (R2 = .94 ± .17) and in magnitude (RMSE=6.2 ± 3.5 Nm) of the primary planes of movement. There were however some temporal fit exceptions for off axes moments with low magnitudes (i.e., < 10 Nm). Bland-Altman plots also indicated acceptable agreement for IVJ peak forces (BU-TD difference of 12 ± 111 and 8 ± 31 N in compression and resultant shear, respectfully). These results support the application of the BU approach and the assigned linked segment parameters of the model. The new BU model is available on the SimTK site (https://simtk.org/projects/spine_ribcage).
Asunto(s)
Vértebras Lumbares , Modelos Biológicos , Vértebras Torácicas , Humanos , Vértebras Lumbares/fisiología , Vértebras Torácicas/fisiología , Masculino , Fenómenos Biomecánicos , Adulto , Femenino , Elevación , Modelos AnatómicosRESUMEN
BACKGROUND: The effect of swimming on bone health remains unclear, namely due to discrepant findings between studies in humans and animal models. OBJECTIVE: The aim of this systematic review and meta-analysis is to identify the available evidence on the effects of swimming on bone mass, geometry and microarchitecture at the lumbar spine, femur and tibia in both humans and rodent animal models. METHODS: The study followed PRISMA guidelines and was registered at PROSPERO (CRD4202236347 and CRD42022363714 for human and animal studies). Two different systematic literature searches were conducted in PubMed, Scopus and Web of Science, retrieving 36 and 16 reports for humans and animal models, respectively. RESULTS: In humans, areal bone mineral density (aBMD) was similar between swimmers and non-athletic controls at the lumbar spine, hip and femoral neck. Swimmers' tibia diaphysis showed a higher cross-sectional area but lower cortical thickness. Inconsistent findings at the femoral neck cortical thickness were found. Due to the small number of studies, trabecular microarchitecture in human swimmers was not assessed. In rodent models, aBMD was found to be lower at the tibia, but similar at the femur. Inconsistent findings in femur diaphysis cross-sectional area were observed. No differences in femur and tibia trabecular microarchitecture were found. CONCLUSION: Swimming seems to affect bone health differently according to anatomical region. Studies in both humans and rodent models suggest that tibia cortical bone is negatively affected by swimming. There was no evidence of a negative effect of swimming on other bone regions, both in humans and animal models.