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1.
Medicine (Baltimore) ; 99(17): e19847, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32332639

RESUMO

BACKGROUND: We set out to evaluate the biomechanical influence of foraminoplasty on intervertebral discs in different areas under lumber percutaneous endoscopy through the use of a three-dimensional finite element. METHODS: We established a normal 3D finite element mode of L3-5, using simulate lumbar percutaneous endoscopy by carrying out cylindrical excision of a bone whose diameter was 7.5 mm on the L5 superior articular process and the L4 inferior articular process, respectively. We therefore obtained 3 models. The first was the normal lumbar model, the second the L4 inferior articular process shaped model, while the third was the L5 superior articular process shaped model. We compared the biomechanics of discs of L3/4 and L4/5 in states of forward flexion, backward extension, left and right flexion as well as left and right rotation. RESULTS: When the L4 inferior articular process shaped model was in backward extension, left rotation, and right rotation, the stress of the L4/5 disc was greater than in the normal model, especially in the state of extension. When the L5 superior articular process shaped model was in left and right rotation, the biggest stress of the L4/5 disc increased slightly. However, no matter which way the L5 superior articular process or the L4 inferior articular process of model was shaped, the stress impact of the L3/4 disc was small. CONCLUSIONS: There is more biomechanical influence on the L4/5 disc when carrying out a foraminoplasty on L4 inferior articular process under a lumber percutaneous endoscopy. In addition, the influence of both types of surgery on the stress of L3/4 disc is small.


Assuntos
Endoscopia/métodos , Análise de Elementos Finitos , Disco Intervertebral/fisiologia , Disco Intervertebral/cirurgia , Vértebras Lombares/fisiologia , Vértebras Lombares/cirurgia , Procedimentos Ortopédicos/métodos , Adulto , Fenômenos Biomecânicos , Humanos , Degeneração do Disco Intervertebral/cirurgia , Masculino , Estresse Mecânico
2.
PLoS One ; 15(2): e0229457, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32084224

RESUMO

PURPOSE: To measure intervertebral disc (IVD) health parameters in middle-aged long-term runners compared to matched non-physically active controls. METHODS: Seventeen males aged 44-62yr were included in the study: 9 runners with a running history of >10yr, averaging >50km/week, and eight matched non-physically active controls, the data from one participant had to be excluded. T2-relaxometry, diffusion weighted imaging, T1- and T2-weighted MR scanning, as well as T2 time mapping were performed. Morphological data relating to IVD were extrapolated. RESULTS: Compared to controls on average, runners had 20% greater IVD height (p = 0.002) and seven percentage points greater IVD-vertebral body height ratio (p = 0.001). No significant differences were observed between groups for mean(SD) IVD hydration status, as indicated by similar T2-times (runners: 94.4(11.1)ms, controls: 88.6(23.6)ms), or apparent diffusion coefficients (runners: 249.0(175.2)mm2/s, controls: 202.3(149.5)mm2/s). Average Pfirrmann score for the L5-S1 IVD was 2.2(0.7) for runners and 3.3(1.0) for controls (p = 0.026), average scores for all lumbar levels (L2-S1) were 1.9(0.2) and 2.5(0.7), respectively (p = 0.036). Anterior annulus T2-time and overall average lumbar level Pfirrmann grades were strongly correlated (r = 0.787, p = 0.021 and r = -0.704, p = 0.034, respectively) with greater distances run per week. Average lumbar level Pfirrmann grades were also strongly correlated (r = -0.823, p = 0.006) to total years of running. CONCLUSION: Middle-aged long-term endurance runners exhibit less age-related decline in their lumbar IVDs. In addition, the measures of IVD morphology appeared to be better in those who had been running for a greater number of years, as well as in those who ran a greater distance per week.


Assuntos
Disco Intervertebral/fisiologia , Vértebras Lombares/fisiologia , Corrida , Adulto , Estudos de Casos e Controles , Estudos Transversais , Humanos , Disco Intervertebral/anatomia & histologia , Vértebras Lombares/anatomia & histologia , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Fatores de Tempo
3.
Br J Radiol ; 93(1109): 20190992, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32101453

RESUMO

OBJECTIVE: To evaluate phantomless assessment of volumetric bone mineral density (vBMD) based on virtual non-contrast images of arterial (VNCa) and venous phase (VNCv) derived from spectral detector CT in comparison to true non-contrast (TNC) images and adjusted venous phase conventional images (CIV(adjusted)). METHODS: 104 consecutive patients who underwent triphasic spectral detector CT between January 2018 and April 2019 were retrospectively included. TNC, VNCa, VNCv and venous phase images (CIV) were reconstructed. vBMD was obtained by two radiologists using an FDA/CE-cleared software. Average vBMD of the first three lumbar vertebrae was determined in each reconstruction; vBMD of CIV was adjusted for contrast enhancement as suggested earlier. RESULTS: vBMD values obtained from CIV(adjusted) are comparable to vBMD values derived from TNC images (91.79 ± 36.52 vs 90.16 ± 41.71 mg/cm3, p = 1.00); however, vBMD values derived from VNCa and VNCv (42.20 ± 22.50 and 41.98 ± 23.3 mg/cm3 respectively) were significantly lower as compared to vBMD values from TNC and CIV(adjusted) (all p ≤ 0.01). CONCLUSION: Spectral detector CT-derived virtual non-contrast images systematically underestimate vBMD and therefore should not be used without appropriate adjustments. Adjusted venous phase images provide reliable results and may be utilized for an opportunistic BMD screening in CT examinations. ADVANCES IN KNOWLEDGE: Adjustments of venous phase images facilitate opportunistic assessment of vBMD, while spectral detector CT-derived VNC images systematically underestimate vBMD.


Assuntos
Densidade Óssea/fisiologia , Vértebras Lombares/fisiologia , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Vértebras Lombares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Estudos Retrospectivos , Sensibilidade e Especificidade , Razão Sinal-Ruído , Tomografia Computadorizada por Raios X/normas , Realidade Virtual
4.
PLoS One ; 15(1): e0227210, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31935225

RESUMO

The role of the ligaments is fundamental in determining the spine biomechanics in physiological and pathological conditions. The anterior longitudinal ligament (ALL) is fundamental in constraining motions especially in the sagittal plane. The ALL also confines the intervertebral discs, preventing herniation. The specific contribution of the ALL has indirectly been investigated in the past as a part of whole spine segments where the structural flexibility was measured. The mechanical properties of isolated ALL have been measured as well. The strain distribution in the ALL has never been measured under pseudo-physiological conditions, as part of multi-vertebra spine segments. This would help elucidate the biomechanical function of the ALL. The aim of this study was to investigate in depth the biomechanical function of the ALL in front of the lumbar vertebrae and of the intervertebral disc. Five lumbar cadaveric spine specimens were subjected to different loading scenarios (flexion-extension, lateral bending, axial torsion) using a state-of-the-art spine tester. The full-field strain distribution on the anterior surface was measured using digital image correlation (DIC) adapted and validated for application to spine segments. The measured strain maps were highly inhomogeneous: the ALL was generally more strained in front of the discs than in front of the vertebrae, with some locally higher strains both imputable to ligament fibers and related to local bony defects. The strain distributions were significantly different among the loading configurations, but also between opposite directions of loading (flexion vs. extension, right vs. left lateral bending, clockwise vs. counterclockwise torsion). This study allowed for the first time to assess the biomechanical behaviour of the anterior longitudinal ligament for the different loading of the spine. We were able to identify both the average trends, and the local effects related to osteophytes, a key feature indicative of spine degeneration.


Assuntos
Disco Intervertebral/fisiologia , Ligamentos Longitudinais/fisiologia , Vértebras Lombares/fisiologia , Idoso , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estresse Mecânico
5.
Radiol Med ; 125(1): 68-74, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31531809

RESUMO

OBJECTIVE: In this study, we prospectively investigated the diagnostic capability of diffusion-weighted magnetic resonance imaging (DWI) in assessing vertebral marrow changes in postmenopausal women with osteoporosis. MATERIALS AND METHODS: Sixty postmenopausal women (mean age 60.2 ± 6.11 years) underwent both dual-energy X-ray absorptiometry (DEXA) of the spine and MRI. Results were acquired from each patient's L2 to L4, for a total of 180 lumbar vertebrae. Based on bone mineral density (BMD) measurements obtained from DEXA, the vertebrae were divided into three groups as follows: normal (n = 52), osteopenic (n = 92), and osteoporotic (n = 36). DWI of the vertebral body was performed to assess the apparent diffusion coefficient (ADC). The ADC outcomes were compared among the three groups and correlated with BMD. RESULTS: ADC values (× 10-6 mm2/s) were significantly lower in the osteoporotic group (135.67 ± 44.10) in comparison to the normal group (561.85 ± 190.37) (P = 0.0001). The results showed a positive correlation between ADC and BMD values (r = 0.748, P = 0.0001). In receiver operating characteristic (ROC) analysis, the area under the curve for DWI was 0.912 (P = 0.001). A cut-off value of 400 mm2/s for the diagnosis of osteoporosis; had sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of 90.90%, 83.34%, 88.89%, 93.75%, and 76.93%, respectively. CONCLUSION: ADC values correlated positively with BMD in women. DWI can allow quantitative evaluation of bone marrow changes and osteoporosis in postmenopausal women.


Assuntos
Densidade Óssea , Medula Óssea/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética , Vértebras Lombares/diagnóstico por imagem , Osteoporose Pós-Menopausa/diagnóstico por imagem , Pós-Menopausa , Absorciometria de Fóton , Área Sob a Curva , Doenças Ósseas Metabólicas/diagnóstico por imagem , Medula Óssea/fisiologia , Feminino , Humanos , Vértebras Lombares/fisiologia , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/classificação , Osteoporose Pós-Menopausa/fisiopatologia , Valor Preditivo dos Testes , Estudos Prospectivos , Curva ROC , Sensibilidade e Especificidade , Estatísticas não Paramétricas
6.
Comput Methods Biomech Biomed Engin ; 23(2): 69-80, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31813282

RESUMO

Finite element method is an efficient tool to investigate the biomechanics of human spine. The key to finite element method is to reconstruct a complete and accurate finite element model. In this study, a three-dimensional finite element model of thoracolumbar structure including complete pelvis (T12-pelvis) was built using computed tomography technology. The modeling process has been explained in detailed. During the process of validation, the model was assigned with non-linear material property for static or dynamic analyses. In static analysis, the vertebral geometry parameters of T12-L5, the axial displacement, the posterior disc bulge and the intradiscal pressure of intervertebral disc, range of motion under six loading cases and facet joint forces were obtained and compared with the experimental data. In dynamic analysis, motion segments were loaded with sinusoidal displacement at 1 Hz in the anterior-posterior and axial directions to verify the reaction force. The first-order resonant frequencies in the vertical direction from one motion segment and two motion segments to the entire model were obtained. The study provides a detailed and accurate method of validation to verify the finite element model of thoracolumbar spine.


Assuntos
Análise de Elementos Finitos , Vértebras Lombares/fisiologia , Modelos Biológicos , Pelve/fisiologia , Vértebras Torácicas/fisiologia , Fenômenos Biomecânicos , Humanos , Reprodutibilidade dos Testes
7.
Int J Occup Saf Ergon ; 26(1): 1-8, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29436289

RESUMO

Purpose. To compare the effects of object handled and handgrip used on lumbar spine motion and loading during occupational lifting task simulations. Methods. Eight male and eight female volunteers performed barbell and crate lifts with a pronated (barbell) and a neutral (crate) handgrip. The mass of barbells/crates lifted was identical across the objects and fixed at 11.6 and 9.3 kg for men and women, respectively. The initial heights of barbells/crates were individualized to mid-shank level. Body segment kinematics and foot-ground reaction kinetics were collected, and then input into an electromyography-assisted dynamic biomechanical model to quantify lumbar spine motion and loading. Results. Lumbar compression and net lumbosacral moment magnitudes were 416 N and 17 Nm lower when lifting a barbell than when lifting a crate (p < 0.001), respectively. There were no between-condition differences in lumbar flexion displacements (p > 0.392) or flexion/extension velocities (p > 0.085). Conclusions. Crate- and barbell-lifting tasks can be used interchangeably if assessing lifting mechanics based on peak spine motion variables. If assessments are based on the spine loading responses to task demands, however, then crate- and barbell-lifting tasks cannot be used interchangeably.


Assuntos
Remoção , Vértebras Lombares/fisiologia , Região Lombossacral/fisiologia , Traumatismos Ocupacionais/prevenção & controle , Adolescente , Adulto , Feminino , Humanos , Masculino , Músculo Esquelético/fisiologia , Saúde do Trabalhador , Postura/fisiologia , Análise e Desempenho de Tarefas , Adulto Jovem
8.
Artigo em Inglês | MEDLINE | ID: mdl-31569358

RESUMO

The purpose of this study is to design a backpack to push the lumbar region forward and confirm the change in the sagittal plane of the spine using radiography when wearing the backpack to present an effective backpack wearing method that can help spinal alignment. Place the question addressed in a broad context and highlight the purpose of the study. A total of 14 adult volunteers participated in the study. The study was carried out on the subjects without carrying a backpack, with a general backpack, and with a backpack designed to push the lumbar region forward. We investigated cervical, thoracic, lumbar, and sacral alignment under these three conditions. Lumbar lordosis showed a significant decrease in the state of wearing a general backpack compared to the case without a backpack, and a significant increase in the state of wearing a backpack designed to push the lumbar region forward rather than a general backpack. In addition, the sacral slope was significantly increased when carrying the backpack designed to push the lumbar region forward, compared to carrying the general backpack. There was a significant correlation between the sacral and lumbar alignment change when wearing the backpack compared to the state without a backpack. The results of this study indicate that wearing a backpack designed to push the lumbar region forward may contribute to the recovery of lumbar lordosis that is reduced when wearing a general backpack. This may be due to an increase in the sacral slope corresponding to the inferior angle of lumbar spine.


Assuntos
Vértebras Lombares/fisiologia , Região Lombossacral/fisiologia , Adulto , Feminino , Humanos , Vértebras Lombares/diagnóstico por imagem , Região Lombossacral/diagnóstico por imagem , Masculino , Adulto Jovem
9.
Artigo em Inglês | MEDLINE | ID: mdl-31618865

RESUMO

Muscle and kidney injury in endurance athletes is worrying for health, and its relationship with physical external workload (eWL) needs to be explored. This study aimed to analyze which eWL indexes have more influence on muscle and kidney injury biomarkers. 20 well-trained trail runners (age = 38.95 ± 9.99 years) ran ~35.27 km (thermal-index = 23.2 ± 1.8 °C, cumulative-ascend = 1815 m) wearing inertial measurement units (IMU) in six different spots (malleolus peroneus [MPleft/MPright], vastus lateralis [VLleft/VLright], lumbar [L1-L3], thoracic [T2-T4]) for eWL measuring using a special suit. Muscle and kidney injury serum biomarkers (creatin-kinase [sCK], creatinine (sCr), ureic-nitrogen (sBUN), albumin [sALB]) were assessed pre-, -post0h and post24h. A principal component (PC) analysis was performed in each IMU spot to extract the main variables that could explain eWL variance. After extraction, PC factors were inputted in multiple regression analysis to explain biomarkers delta change percentage (Δ%). sCK, sCr, sBUN, sALB presented large differences (p < 0.05) between measurements (pre < post24h < post0h). PC's explained 77.5-86.5% of total eWL variance. sCK Δ% was predicted in 40 to 47% by L1-L3 and MPleft; sCr Δ% in 27% to 45% by L1-L3 and MPleft; and sBUN Δ% in 38%-40% by MPright and MPleft. These findings could lead to a better comprehension of how eWL (impacts, player load and approximated entropy) could predict acute kidney and muscle injury. These findings support the new hypothesis of mechanical kidney injury during trail running based on L1-L3 external workload data.


Assuntos
Lesão Renal Aguda/fisiopatologia , Treino Aeróbico , Rim/fisiopatologia , Músculos/lesões , Corrida/fisiologia , Lesão Renal Aguda/sangue , Adulto , Atletas , Biomarcadores/sangue , Creatinina/sangue , Humanos , Vértebras Lombares/fisiologia , Masculino , Pessoa de Meia-Idade , Vértebras Torácicas/fisiologia
10.
J Orthop Surg Res ; 14(1): 246, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31382997

RESUMO

BACKGROUND: While there are several different animal models for use in the characterization of spinal fixation, none have emerged as a definitive model for comparative studies in spinal fixation methods. The purpose of this study is to establish morphometric data of porcine vertebrae and to characterize the feasibility of pedicle screw fixation in porcine spines for potential comparative human study. METHODS: Four spines from 45 to 50 kg Hanford minipigs were cleaned of soft tissue and analyzed by computed tomography and dual-energy x-ray absorptiometry. Two 5 × 30-mm pedicle screws were placed in each vertebra and tested to failure using a combined moment-load protocol. RESULTS: Pedicle widths were measured from L6-T5. Widths ranged from 7.15 mm (T6) to 9.24 mm (T14). Posterior cortex to anterior cortex depth ranged from 25.9 to 32.6 mm. Mean bone mineral density was 1.0665 g/cm2 (range 1.139-1.016). Force-to-failure demonstrated mean 1171.40 N (+ 115.34). CONCLUSION: Our baseline morphometric and compositional data demonstrate that porcine vertebrae can serve as a useful model for comparative studies due to their similar pedicle widths and bone mineral density to the human vertebra. This biomechanical data could provide a baseline comparison for future studies. This study also suggests that the minipig could be a suitable model for comparative studies due to similarities in pedicle width and bone mineral density to the human vertebrae.


Assuntos
Densidade Óssea/fisiologia , Vértebras Lombares/fisiologia , Vértebras Lombares/cirurgia , Modelos Animais , Parafusos Pediculares , Animais , Fenômenos Biomecânicos/fisiologia , Vértebras Lombares/diagnóstico por imagem , Suínos , Porco Miniatura
11.
Med Biol Eng Comput ; 57(10): 2305-2318, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31444622

RESUMO

Degenerative disc disease (DDD) is a common condition in elderly population that can be painful and can significantly affect individual's quality of life. Diagnosis of DDD allows prompt corrective actions but it is challenging due to the absence of any symptoms at early stages. In studying disc degeneration, measurement of the range of motion (RoM) and loads acting on the spine are crucial factors. However, direct measurement of RoM involves increased instrumentation and risk. In this paper, an innovative method is proposed for calculating RoM, emphasizing repeatability and reliability by considering the posterior thickness of the spine. This is achieved by offsetting the position of markers in relation to the actual vertebral loci. Three geometrically identical finite element models of L3-L4 are developed from a CT scan with different types of elements, and thereafter, mesh element-related metrics are provided for the assessment of the quality of models. The model with the best mesh quality is used for further analysis, where RoM are within ranges as reported in literature and in vivo experiment results. Various kinds of stresses acting on individual components including facet joints are analysed for normal and abnormal loading conditions. The results showed that the stresses in abnormal load conditions for all components including cortical (76.67 MPa), cancellous (69.18 MPa), annulus (6.30 MPa) and nucleus (0.343 MPa) are significantly greater as compared to normal loads (49.96 MPa, 44.2 MPa, 4.28 MPa and 0.23 MPa respectively). However, stress levels for both conditions are within safe limits (167-215 MPa for cortical, 46 MPa for the annulus and 3 MPa for facets). The results obtained could be used as a baseline motion and stresses of healthy subjects based on their respective lifestyles, which could benefit clinicians to suggest corrective actions for those affected by DDD.


Assuntos
Simulação por Computador , Vértebras Lombares/fisiologia , Modelos Biológicos , Amplitude de Movimento Articular/fisiologia , Análise de Elementos Finitos , Humanos , Disco Intervertebral/fisiopatologia , Vértebras Lombares/diagnóstico por imagem , Masculino , Reprodutibilidade dos Testes , Estresse Mecânico , Tomografia Computadorizada por Raios X , Suporte de Carga , Adulto Jovem
12.
IEEE Int Conf Rehabil Robot ; 2019: 625-630, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31374700

RESUMO

Industrial active exoskeletons have recently achieved considerable interest, due to their intrinsic versatility compared to passive devices. To achieve this versatility, an important open challenge is the design of appropriate control strategies to automatically modulate the physical assistance according to the activity the user is performing.This work focuses on active back-support exoskeletons. To improve the assistance provided in dynamic situations with respect to state-of-the-art methods, a new strategy making use of the angular acceleration of the user's trunk is presented.The feasibility and effectiveness of the proposed strategy were tested experimentally on a prototype in a load handling task. The main advantages in terms of assistive torque profiles emerge during the transition phases of the movement (i.e. beginning and end of lowering and lifting) indicating an appropriate adaptation to the dynamics of the execution.In this preliminary evaluation, the data on peak muscular activity at the spine show promising trends, encouraging further developments and a more detailed evaluation.


Assuntos
Aceleração , Exoesqueleto Energizado , Equipamentos de Autoajuda , Humanos , Vértebras Lombares/fisiologia , Torque , Suporte de Carga
13.
Comput Methods Biomech Biomed Engin ; 22(14): 1135-1143, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31362525

RESUMO

The current paper aims at assessing the sensitivity of muscle and intervertebral disc force computations against potential errors in modeling muscle attachment sites. We perturbed each attachment location in a complete and coherent musculoskeletal model of the human spine and quantified the changes in muscle and disc forces during standing upright, flexion, lateral bending, and axial rotation of the trunk. Although the majority of the muscles caused minor changes (less than 5%) in the disc forces, certain muscle groups, for example, quadratus lumborum, altered the shear and compressive forces as high as 353% and 17%, respectively. Furthermore, percent changes were higher in the shear forces than in the compressive forces. Our analyses identified certain muscles in the rib cage (intercostales interni and intercostales externi) and lumbar spine (quadratus lumborum and longissimus thoracis) as being more influential for computing muscle and disc forces. Furthermore, the disc forces at the L4/L5 joint were the most sensitive against muscle attachment sites, followed by T6/T7 and T12/L1 joints. Presented findings suggest that modeling muscle attachment sites based on solely anatomical illustrations might lead to erroneous evaluation of internal forces and promote using anatomical datasets where these locations were accurately measured. When developing a personalized model of the spine, certain care should also be paid especially for the muscles indicated in this work.


Assuntos
Disco Intervertebral/fisiologia , Músculo Esquelético/fisiologia , Fenômenos Biomecânicos , Força Compressiva , Humanos , Vértebras Lombares/fisiologia , Masculino , Modelos Anatômicos
14.
J Orthop Surg Res ; 14(1): 264, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31451116

RESUMO

BACKGROUND: To investigate the incidence of scoliosis and trunk shift in patients with LDH (lumbar disc herniation) and analyze the differences in spinopelvic alignment among patients with or without trunk shift and non-symptom controls. MATERIALS AND METHODS: All included subjects had standard upright antero-posterior and lateral radiographs of the whole spine taken. Evidence of disc herniation was confirmed by computed tomography or magnetic resonance imaging. The parameters measured included trunk shift and Cobb angle, TK (thoracic kyphosis), TLK (thoraco-lumbar junction kyphosis), LL (lumbar lordosis), PI (pelvic incidence), SS (sacral slope), PT (pelvic tilt) and SVA (sagittal vertical axis). RESULTS: Sixty-eight patients with LDH and 61 controls were included. There were significantly more male patients with trunk shift than the patients without trunk shift. Forty-two patients had curve magnitudes ranging from 5 to 38°. The trunk shift ranged from 0.5 to 7.3 cm. A total of 54.76% of patients had a disc herniation on the concave side of the main curve. Fifty percent of patients showed a trunk shift towards the opposite side of disc herniation. There were significant differences in spinopelvic parameters among groups. Significant correlations were also observed between several spinopelvic parameters in the three groups. However, the degrees of correlations among the spinopelvic parameters differed among the three groups. CONCLUSION: Spinal sagittal morphology in LDH patients with trunk shift exhibits a more anterior shift of the C7 plumb line, less LL, and a more horizontal sacrum. Correlation analysis indicated a disharmonious spinopelvic interaction and a change in the compensatory model in patients with LDH.


Assuntos
Deslocamento do Disco Intervertebral/diagnóstico por imagem , Vértebras Lombares/diagnóstico por imagem , Postura/fisiologia , Escoliose/diagnóstico por imagem , Adulto , Idoso , Feminino , Humanos , Deslocamento do Disco Intervertebral/fisiopatologia , Vértebras Lombares/fisiologia , Masculino , Pessoa de Meia-Idade , Sacro/diagnóstico por imagem , Sacro/fisiologia , Escoliose/fisiopatologia , Vértebras Torácicas/diagnóstico por imagem , Vértebras Torácicas/fisiologia , Adulto Jovem
15.
Ann Hum Biol ; 46(5): 430-433, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31448632

RESUMO

In this study, VDR gene ApaI (rs7975232), BsmI (rs 1544410) and TaqI (rs731236) genotypes were compared in men with osteoporosis and male controls. Osteoporosis affects around 20% of all men and overall mortality in the first year after hip fracture is significantly higher in men than women, yet the genetic basis of osteoporosis is less well studied in males. This study consisted of White British males; 69 osteoporosis patients and 122 controls. BMDs at the lumbar spine (vertebrae L1-L4) and hip (femur neck) were measured by dual-energy X-ray absorptiometry (DEXA). The VDR gene ApaI, BsmI and TaqI genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and association analysis was carried out at genotype and haplotype level. Our study suggests that TaqI polymorphism CC genotype frequency is lower in controls and further analysis of genotypes and BMD revealed a significant effect of TaqI polymorphism on Lumbar spine BMD. Two haplotypes (GCC and AAT) were associated with increased osteoporosis risk. In conclusion, VDR gene TaqI polymorphism in recessive mode had a significant effect on lumbar spine BMD within our study. Haplotypes GCC and AAT increase the risk of osteoporosis among White British males.


Assuntos
Densidade Óssea/genética , Osteoporose/genética , Polimorfismo Genético , Receptores de Calcitriol/genética , Absorciometria de Fóton , Idoso , Estudos de Casos e Controles , Colo do Fêmur/fisiologia , Genótipo , Haplótipos , Humanos , Vértebras Lombares/fisiologia , Masculino , Pessoa de Meia-Idade , Osteoporose/epidemiologia , Fatores de Risco , Reino Unido/epidemiologia
16.
Med Sci Monit ; 25: 4751-4758, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31280279

RESUMO

BACKGROUND Center of rotation (COR) has been used for assessing spinal motion quality. However, the biomechanical influence of COR deviation towards different directions during flexion-extension (FE) remains largely unknown. This study aimed to investigate the alteration in the range of motion (ROM), compressive force, shear force, and neutral zone size (NZ) in a lumbar functional spinal unit (FSU), caused by the deviated COR in different directions during FE. MATERIAL AND METHODS Twelve human cadaveric lumbar FSUs (6 for L2-L3, 6 for L4-L5) were tested in a 6-degree-of-freedom servo-hydraulic load frame. These FSUs were firstly applied a 7.5 Nm pure moment to perform FE to obtain their natural COR during FE. Subsequently, they were subjected to FE around 9 established deviated CORs with 6 Nm cyclical loading. RESULTS It was found that the ROM and NZ increased significantly when the COR moved from the superior plane to the inferior plane for the L2-L3 unit and when the COR located in the superior plane compared with the inferior plane for the L4-L5 unit. The compressive forces for both FSUs demonstrated significant changes caused by COR shift in the same horizontal plane, while the shear forces demonstrated significant changes caused by COR shift in the same vertical plane. CONCLUSIONS The ROM, NZ, and shear force of FSU are sensitive to the vertical COR shift, while the compressive force of FSU is highly sensitive to the horizontal COR shift. Additionally, the kinematics and kinetics of the L2-L3 unit are more sensitive to COR location than those of the L4-L5 unit.


Assuntos
Vértebras Lombares/fisiologia , Rotação , Adulto , Fenômenos Biomecânicos , Cadáver , Força Compressiva , Humanos , Cinética , Movimento (Física) , Amplitude de Movimento Articular
17.
Work ; 63(4): 603-613, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31282457

RESUMO

BACKGROUND: Physical employment standards (PES) ensure that candidates can demonstrate the physical capacity required to perform duties of work. However, movement competency, or an individual's movement strategy, can relate to injury risk and safety, and therefore should be considered in PES. OBJECTIVE: Demonstrate the utility of using artificial intelligence (AI) to detect risk-potential of different movement strategies within PES. METHODS: Biomechanical analysis was used to calculate peak flexion angles and peak extensor moment about the lumbar spine during participants' performance of a backboard lifting task. Lifts performed with relatively lower and higher exposure to postural and moment loading on the spine were characterized as "low" or "high" exposure, respectively. An AI model including principal component and linear discriminant analyses was then trained to detect and classify backboard lifts as "low" or "high". RESULTS: The AI model accurately classified over 85% of lifts as "low" or "high" exposure using only motion data as an input. CONCLUSIONS: This proof-of-principle demonstrates that movement competency can be assessed in PES using AI. Similar classification approaches could be used to improve the utility of PES as a musculoskeletal disorders (MSD) prevention tool by proactively identifying candidates at higher risk of MSD based on movement competency.


Assuntos
Emprego/normas , Movimento/fisiologia , Traumatismos Ocupacionais/prevenção & controle , Exame Físico/métodos , Aptidão Física/fisiologia , Adulto , Pessoal Técnico de Saúde/normas , Inteligência Artificial , Fenômenos Biomecânicos/fisiologia , Avaliação de Desempenho Profissional/métodos , Avaliação de Desempenho Profissional/normas , Estudos de Viabilidade , Feminino , Humanos , Vértebras Lombares/fisiologia , Masculino , Exame Físico/normas , Estudo de Prova de Conceito , Amplitude de Movimento Articular/fisiologia , Medição de Risco/métodos , Adulto Jovem
18.
Comput Methods Programs Biomed ; 177: 39-46, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31319959

RESUMO

BACKGROUND AND OBJECTIVE: The objective of this study was to investigate the effect of incorporating various passive elements, which could represent combined or individual effects of intervertebral disc, facet articulation and ligaments, on the prediction of lumbar muscle activation and L4-L5 intradiscal pressure. METHODS: The passive elements representing the intervertebral disc, facet articulations, and ligaments were added to the existed lumbar musculoskeletal model with nonlinear rotational stiffness or force-strain relationships. The model was fed with kinematics of trunk flexion, extension, axial rotation and lateral bending to calculate muscle activation and L4-L5 intradiscal pressure. RESULTS: In the trunk axial rotation, the intradiscal pressure values predicted by the models with elements representing facet articulation were much higher than that predicated by models removing these elements. In the trunk flexion, the models with passive elements showed lower muscle activation of extensors than model with no passive elements. At the end of trunk flexion, extension, axial rotation and lateral bending, the intradiscal pressure values predicted by model with intact passive elements were 120.6%, 92.5%, 334.8% and 74.9% of the values predicted by model with no passive elements, respectively. CONCLUSIONS: Caution must be taken while modeling facet articulation as elements with rotational stiffness, as they may lead to overestimation of intradiscal pressure in trunk axial rotation. The inclusion of ligaments as spring-like elements may improve the simulation of flexion-relaxation phenomenon in trunk flexion. Future models considering detailed properties of passive elements are needed to allow more access to understanding the mechanics of the lumbar spine.


Assuntos
Músculos do Dorso/fisiologia , Disco Intervertebral/fisiologia , Vértebras Lombares/fisiologia , Região Lombossacral/fisiologia , Adulto , Fenômenos Biomecânicos , Simulação por Computador , Humanos , Ligamentos , Masculino , Modelos Anatômicos , Movimento , Pressão , Amplitude de Movimento Articular , Rotação , Estresse Mecânico , Tomografia Computadorizada por Raios X
19.
Comput Methods Biomech Biomed Engin ; 22(15): 1163-1173, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31361152

RESUMO

The spine or 'back' has many functions including supporting our body frame whilst facilitating movement, protecting the spinal cord and nerves and acting as a shock absorber. In certain instances, individuals may develop conditions that not only cause back pain but also may require additional support for the spine. Common movements such as twisting, standing and bending motions could exacerbate these conditions and intensify this pain. Back braces can be used in certain instances to constrain such motion as part of an individual's therapy and have existed as both medical and retail products for a number of decades. Arguably, back brace designs have lacked the innovation expected in this time. Existing designs are often found to be heavy, overly rigid, indiscrete and largely uncomfortable. In order to facilitate the development of new designs of back braces capable of being optimised to constrain particular motions for specific therapies, a numerical and experimental design strategy has been devised, tested and proven for the first time. The strategy makes use of an experimental test rig in conjunction with finite element analysis simulations to investigate and quantify the effects of back braces on flexion, extension, lateral bending and torsional motions as experienced by the human trunk. This paper describes this strategy and demonstrates its effectiveness through the proposal and comparison of two novel back brace designs.


Assuntos
Braquetes , Coluna Vertebral/fisiologia , Simulação por Computador , Desenho Assistido por Computador , Análise de Elementos Finitos , Humanos , Vértebras Lombares/anatomia & histologia , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/fisiologia , Modelos Anatômicos , Movimento , Desenho de Prótese , Amplitude de Movimento Articular , Coluna Vertebral/anatomia & histologia , Coluna Vertebral/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Torção Mecânica
20.
Int J Occup Environ Med ; 10(3): 137-144, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31325296

RESUMO

BACKGROUND: The chair influences the position of the user in relation to his or her devices. Prolonged static sitting is a frequently mentioned risk factor for low back pain. Seat design, thus, plays an important role in the study of human sitting. Quantitative information is needed on what happens to body when one sits in chairs with different seat depth. OBJECTIVE: To determine the myoelectric activity (EMG) of individual lumbar erector spinae muscles after sitting in chairs with different seat pan depth. METHODS: EMG recordings were taken using surface electrodes placed on the lumbar erector spine muscles of 25 normal, volunteer subjects. EMG recordings for muscle activity were made while the study participants were in a comfortable position and performed the required tasks. The experiments investigated with 3 seat depths according to the 5th, 50th and 95th percentiles of the buttock popliteal length. The recorded EMG data were normalized to the maximal voluntary contraction. The mean EMG recording was calculated for each of the 3 chairs tested. A mixed model was used to assess the differences among the situations. RESULTS: A significant (p<0.05) difference was observed between the mean EMG recordings for the 3 tested seat pan depths. EMG activity was higher in seats with the 5th and 95th percentiles compared with that for the seat with 50th percentile of buttock popliteal length depth. CONCLUSION: The seat pan depth used during a comfortable position has a significant effect on the level of myoelectric activity in the lumbar erector spinal muscles. The finding of this study may contribute to our understanding of the biomechanics of sitting.


Assuntos
Músculos do Dorso/fisiologia , Fenômenos Biomecânicos/fisiologia , Vértebras Lombares/fisiologia , Postura Sentada , Adulto , Antropometria , Eletromiografia , Ergonomia , Feminino , Humanos , Dor Lombar/fisiopatologia , Masculino
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