Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.864
Filtrar
1.
Medicine (Baltimore) ; 100(8): e24803, 2021 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-33663098

RESUMO

RATIONALE: Melanotic schwannoma (MS) is an unusual variant of a nerve sheath neoplasm that accounts for less than 1% of all primary peripheral nerve sheath tumors. Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has unique value in detecting malignant MS lesions. To date, only 4 cases of MS with hepatic metastasis have been reported. Herein, we report the fifth case, which is the first reported patient with MS of Asian ethnicity with hepatic metastasis. PATIENT CONCERNS: A 29-year-old woman with a 1-day history of backache was admitted to our hospital. PET/CT showed a paravertebral heterogeneous soft tissue mass along the spinal nerve at the L2-L3 level with strong FDG uptake, and a nodule with increased FDG uptake in the lateral lobe of the left liver. DIAGNOSIS: A puncture biopsy of the L3 bony destruction and surrounding soft tissue mass was performed. The final diagnosis was spinal MS with hepatic metastasis. INTERVENTIONS: The patient underwent 6 courses of systemic chemotherapy. OUTCOMES: The patient did not receive further treatment for half a year after the end of chemotherapy and recovered well. LESSONS: Unlike conventional schwannomas, which are completely benign, MS has an unpredictable prognosis. It is thought to have low malignant potential, and the malignant type tends to metastasize. FDG PET/CT has a unique and important value in the differential diagnosis of benign and malignant lesions, in detecting occult metastases, monitoring the treatment response, and assessing the prognosis of MS.


Assuntos
Fluordesoxiglucose F18/administração & dosagem , Neurilemoma/diagnóstico , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Compostos Radiofarmacêuticos/administração & dosagem , Neoplasias da Coluna Vertebral/diagnóstico , Adulto , Antineoplásicos/uso terapêutico , Feminino , Humanos , Neoplasias Hepáticas/secundário , Vértebras Lombares/fisiologia , Neurilemoma/diagnóstico por imagem , Neurilemoma/tratamento farmacológico , Neurilemoma/patologia , Neoplasias da Coluna Vertebral/diagnóstico por imagem , Neoplasias da Coluna Vertebral/tratamento farmacológico , Neoplasias da Coluna Vertebral/patologia , Raízes Nervosas Espinhais/patologia
2.
J Electromyogr Kinesiol ; 57: 102531, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33607359

RESUMO

Repetitive trunk flexion can damage spinal tissues, however its association with low back pain in the workplace may be confounded by factors related to pain sensitivity. Muscle fatigue, exercise-induced hypoalgesia, and creep-induced neuromuscular changes following repetitive trunk flexion may all affect this assumed exposure-pain relationship. This study's purpose was to determine how mechanical pain sensitivity in the low back is affected by a repetitive trunk flexion exposure and identify factors associated with changes in low back pain sensitivity. Pressure pain thresholds, perceptions of sub-threshold stimuli, and muscle fatigue in the trunk and tibia, as well as lumbar spine creep were tracked in 37 young healthy adults before and up to 40 min after a 10-min repetitive trunk flexion exposure. Pressure pain thresholds (p = 0.033), but not perceptions of sub-threshold stimuli (p > 0.102) were associated with approximately a 12.5% reduction in pain sensitivity 10 min after completing the exposure, while creep and local muscle fatigue effects were only observed immediately following the exposure. Creep and fatigue interactions and the corresponding tibial measure co-varied with individual low back pressure pain thresholds. The net hypoalgesic effects of repetitive trunk flexion have the potential to partially mask possibly injurious loads, which could contribute to the severity or incidence of lower back injuries related to these exposures.


Assuntos
Dor Lombar/fisiopatologia , Vértebras Lombares/fisiologia , Contração Muscular/fisiologia , Fadiga Muscular/fisiologia , Tronco/fisiologia , Adulto , Eletromiografia/métodos , Feminino , Humanos , Dor Lombar/diagnóstico , Masculino , Músculo Esquelético/fisiologia , Medição da Dor/métodos , Amplitude de Movimento Articular/fisiologia , Adulto Jovem
3.
J Bone Miner Metab ; 39(3): 484-493, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33389132

RESUMO

INTRODUCTION: There have been no reports of the effects of baseline lumbar spine bone mineral density (LS-BMD) and bone turnover marker levels on the therapeutic effect of a 28.2-µg teriparatide formulation for twice-weekly use (2/W-TPTD). MATERIALS AND METHODS: An analysis was performed using data from a double-blind, randomized, non-inferiority trial (TWICE study) conducted with patients who received 2/W-TPTD or a 56.5-µg teriparatide formulation for once-weekly use (1/W-TPTD) for 48 weeks. The patients were divided into tertile groups based on baseline LS-BMD, urinary type I collagen cross-linked N-telopeptide (u-NTX), and serum type I procollagen-N-propeptide (P1NP) levels, respectively. Time profiles of these measurements were analyzed. Furthermore, whether a change in P1NP is a predictor for percentage change in BMD was assessed. RESULTS: Across all tertile groups divided based on baseline LS-BMD and levels of bone turnover markers, the LS-BMD increased significantly. The u-NTX level decreased throughout the study period in the high- and middle-u-NTX-level groups. The P1NP level increased after 4 weeks, but subsequently decreased after 12 weeks and thereafter in the high-P1NP-level group; it increased after 4 weeks and subsequently fluctuated near the baseline level in the middle-P1NP-level group. A cut-off value of 12.0 µg/L for change in P1NP after 4 weeks of 2/W-TPTD as a predictor for percentage change in LS-BMD of 3% or more after 48 weeks gave a positive predictive value of 89.6%. CONCLUSION: 2/W-TPTD, just like 1/W-TPTD, improved LS-BMD significantly, regardless of baseline LS-BMD and bone turnover marker levels.


Assuntos
Biomarcadores/sangue , Densidade Óssea/efeitos dos fármacos , Remodelação Óssea/efeitos dos fármacos , Vértebras Lombares/fisiologia , Teriparatida/farmacologia , Idoso , Conservadores da Densidade Óssea/farmacologia , Conservadores da Densidade Óssea/uso terapêutico , Colágeno Tipo I/sangue , Método Duplo-Cego , Esquema de Medicação , Análise Fatorial , Feminino , Humanos , Vértebras Lombares/efeitos dos fármacos , Masculino , Peptídeos/sangue , Curva ROC , Fatores de Tempo
4.
Artigo em Inglês | MEDLINE | ID: mdl-33401569

RESUMO

Previous studies have demonstrated that the angle of women's lumbar curvature affects men's attractiveness judgments of them. The theoretically optimal angle of lumbar curvature provides better resistance against both hyperlordosis and hypolordosis as biomechanical costs of a bipedal fetal load that could impair a woman's fertility. Since men find this attribute attractive, women aim to emphasize it by wearing high-heeled shoes. The primary objective of the present study was to test this evolutionary hypothesis using short videos presenting women walking by the camera. In line with previous findings based on static stimuli (photographs), dynamic stimuli (videos) presenting women walking in high-heeled shoes were expected to elicit increased attractiveness ratings as compared to women wearing flat shoes, which would be associated with the angle of lumbar curvature. Videos were taken of 52 female models walking in two conditions (i.e., wearing either high-heeled or flat shoes). A total of 108 participants (61 males, 47 females) rated the walking models' physical attractiveness in an online setting. Each model's lumbar curvature was measured both in high heels and in flat shoes using photographs taken of them prior to each video recording. The results showed that wearing high heels consistently increased the models' attractiveness, regardless of whether or not it decreased their natural difference from the theoretically optimal angle of lumbar curvature. Both male and female observers showed this positive effect. Furthermore, a negative correlation was found between the models' body mass index (BMI) and their perceived attractiveness scores in both conditions.


Assuntos
Sapatos , Caminhada , Adolescente , Beleza , Feminino , Humanos , Vértebras Lombares/fisiologia , Masculino , Sapatos/estatística & dados numéricos , Gravação de Videoteipe , Caminhada/fisiologia , Adulto Jovem
5.
Am J Phys Anthropol ; 174(1): 66-75, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32860450

RESUMO

OBJECTIVES: Human walking involves out-of-phase axial rotations of the thorax and pelvis. It has long been believed that this rotational capability is a distinctive feature of the genus Homo. However, Thompson et al. (2015) showed that chimpanzees also counter-rotate their thorax relative to the pelvis during bipedal walking, which raised questions regarding the origins and development of this characteristic. In this study, we measured the axial rotation of the trunk during bipedal walking in humans and macaques to investigate if intra-trunk axial rotations are observed in non-hominoid primate species. MATERIALS AND METHODS: We collected three-dimensional trunk kinematic data during bipedal walking in six humans and five Japanese macaques. The human subjects walked on a treadmill, and the animal subjects walked on a 5-m runway. During walking, the positions of cluster markers, which defined trunk segments, were recorded by multiple video cameras. Segmental xyz coordinates were digitized, and transverse rotations were calculated using motion analysis software. RESULTS: Although trunk rotations in the global coordinate system were greater in macaques than in humans, the intra-trunk rotation and range of motion showed a similar pattern in the two species. CONCLUSIONS: Thoracic rotation relative to the pelvis during bipedal walking is not unique to the hominid lineage but rather a characteristic generated by the mechanical requirements of bipedal walking. The fact that the range of motion of counter rotation is similar in these species infers that an optimal range of rotation exists for bipedal walking.


Assuntos
Fenômenos Biomecânicos/fisiologia , Macaca fuscata/fisiologia , Tronco/fisiologia , Caminhada/fisiologia , Adulto , Animais , Antropologia Física , Humanos , Vértebras Lombares/fisiologia , Masculino , Amplitude de Movimento Articular/fisiologia , Rotação , Adulto Jovem
6.
Medicine (Baltimore) ; 99(28): e21178, 2020 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-32664159

RESUMO

Lumbar and pelvic alignment may have a huge impact on the posture of the spine and other parts. The aim of this study were to compare the spinal curvature of the cervical, thoracic, and lumbar spine and the muscle activity of the cervical erector spinae muscle, upper trapezius muscle, and thoracic erector spinae muscle when sitting at 3 different sloped, seating surfaces. A 10° wedge was used as the seating surface and we compared a forward sloping seat surface, a flat seating surface, and a rear sloping seat surface, in that order. Twenty healthy officers were recruited for this study. The subjects sat on the seat of 3 different slopes and watched a total of 3 videos, 10 minutes each. The rest time was 10 minutes. Subjects were photographed while viewing videos and muscle activity was measured. There were significant differences in cervical, thoracic, lumbar curvatures, and muscle activity in the 3 different sitting positions according to seat tilt (P < .05). Among the 3 slopes, the forward slope decreased forward head posture and cervical erector spinae muscle activity (P < .05). The activity of the cervical erector spinae muscle was 2.67% with a forward sloping seat, 5.45% with a flat sloping seat, and 6.77% with a rear sloping seat, revealing a significant difference (P < .05). This suggests that a forward sloping seat surface was effective in maintaining a neutral alignment of the spine, and this decreased the cervical spine erector muscle activity. Based on this result, equipment and chair development to incline seats forward may improve posture and health, and prevent chronic pain.


Assuntos
Músculos do Dorso/fisiologia , Postura Sentada , Curvaturas da Coluna Vertebral/fisiopatologia , Coluna Vertebral/fisiologia , Adulto , Músculos do Dorso/diagnóstico por imagem , Fenômenos Biomecânicos , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/fisiologia , Feminino , Cabeça , Voluntários Saudáveis , Humanos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/fisiologia , Masculino , Pescoço/diagnóstico por imagem , Pescoço/fisiologia , Pelve/diagnóstico por imagem , Pelve/fisiologia , Curvaturas da Coluna Vertebral/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagem , Vértebras Torácicas/diagnóstico por imagem , Vértebras Torácicas/fisiologia
7.
J Sports Sci ; 38(10): 1085-1095, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32281483

RESUMO

Fast bowling is categorised into four action types: side-on, front-on, semi-open and mixed; however, little biomechanical comparison exists between action types in junior fast bowlers. This study investigated whether there are significant differences between action-type mechanics in junior fast bowlers. Three-dimensional kinematic and kinetic analyses were completed on 60 junior male fast bowlers bowling a five-over spell. Mixed-design factorial analyses of variance were used to test for differences between action-type groups across the phases of the bowling action. One kinetic difference was observed between groups, with a higher vertical ground reaction force loading rate during the front-foot contact phase in mixed and front-on compared to semi-open bowlers; no other significant group differences in joint loading occurred. Significant kinematic differences were observed between the front-on, semi-open and mixed action types during the front-foot contact phase for the elbow and trunk. Significant kinematic differences were also present for the ankle, T12-L1, elbow, trunk and pelvis during the back-foot phase. Overall, most differences in action types for junior fast bowlers occurred during the back-foot contact phase, particularly trunk rotation and T12-L1 joint angles/ranges of motion, where after similar movement patterns were utilized across groups during the front-foot contact phase.


Assuntos
Esportes/classificação , Esportes/fisiologia , Adolescente , Fenômenos Biomecânicos , Humanos , Extremidade Inferior/fisiologia , Vértebras Lombares/fisiologia , Masculino , Pelve/fisiologia , Amplitude de Movimento Articular , Vértebras Torácicas/fisiologia , Estudos de Tempo e Movimento , Tronco/fisiologia , Extremidade Superior/fisiologia
8.
Clin J Sport Med ; 30(3): 245-250, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32341292

RESUMO

OBJECTIVE: To determine whether secondary amenorrhea during teenage years influences bone mineral density (BMD) in female athletes in their 20s. DESIGN: Original research. SETTING: Japan Institute of Sports Sciences. PARTICIPANTS: Two hundred ten elite female athletes older than 20 years were included in the study. MAIN OUTCOME MEASURES: Information on the participants' past (ie, during their teenage years) and current menstrual cycle, training time, history of stress fractures, and blood tests for hormones received was obtained. Bone mineral density of the lumbar spine was evaluated by dual-energy x-ray absorptiometry; low BMD was defined as a Z-score ≤-1. We investigated the correlation factors for low BMD in athletes in their 20s by univariable and multivariable logistic regression analysis. RESULTS: A total of 39 (18.6%) female athletes had low BMD. Secondary amenorrhea in their teens [odds ratio (OR), 7.11, 95% confidence interval (CI), 2.38-21.24; P < 0.001] and present body mass index (BMI) (OR, 0.56, 95% CI, 0.42-0.73; P < 0.001) were independent correlation factors for low BMD in the multivariable logistic regression analysis. The average Z-score for those with secondary amenorrhea in their teens and 20s, secondary amenorrhea in their 20s only, and regular menstruation was -1.56 ± 1.00, -0.45 ± 1.21, and 0.82 ± 1.11 g/cm, respectively. CONCLUSIONS: Secondary amenorrhea for at least 1 year during teenage years in female athletes and BMI at present was strongly associated with low BMD in their 20s.


Assuntos
Amenorreia/fisiopatologia , Densidade Óssea/fisiologia , Doenças Ósseas Metabólicas/fisiopatologia , Esportes/fisiologia , Absorciometria de Fóton , Adolescente , Amenorreia/prevenção & controle , Índice de Massa Corporal , Doenças Ósseas Metabólicas/prevenção & controle , Estradiol/sangue , Feminino , Humanos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/fisiologia , Hormônio Luteinizante/sangue , Ciclo Menstrual/fisiologia , Adulto Jovem
9.
Comput Methods Biomech Biomed Engin ; 23(10): 585-596, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32324052

RESUMO

Thoracolumbar fascia involvement is often neglected when studying the biomechanics of the spine. The purpose of this study was to develop, validate, and explore the use of a novel finite element model of the spine, inclusive of the Thoracolumbar Fascia, Paraspinal Muscular Compartment (PMC) and the Intra-Abdominal Pressure (IAP) based on published clinical studies. Reaction forces were acquired at five critical anatomical locations. Results showed that elevated IAP decreased the posterior force and balanced the anterior forces when PMC pressure was asymmetric. This novel finite element study demonstrated a link between the TLF compartments supporting its involvement in spinal stability.


Assuntos
Abdome/fisiologia , Fáscia/fisiologia , Análise de Elementos Finitos , Vértebras Lombares/fisiologia , Músculos Paraespinais/fisiologia , Pressão , Vértebras Torácicas/fisiologia , Fenômenos Biomecânicos/fisiologia , Simulação por Computador , Módulo de Elasticidade , Humanos , Modelos Biológicos
10.
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
11.
Ergonomics ; 63(4): 505-521, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32024437

RESUMO

The objectives of this study were to quantify loads imposed upon the lumbar spine while lifting/lowering with one versus two hands and to create guidelines for one-handed lifting/lowering that are protective of the lower back. Thirty subjects (15 male, 15 female) performed one- and two-handed exertions in a laboratory, lifting from/lowering to 18 lift origins/destinations using medicine balls of varying masses. An electromyography-assisted model predicted peak spinal loads, which were related to tissue tolerance limits to create recommended weight limits. Compared to two-handed exertions, one-handed exertions resulted in decreased spinal compression and A/P shear loading (p < 0.001) but increased lateral shear (p < 0.001). Effects were likely driven by altered moment exposures attributable to altered torso kinematics. Differences between spinal loads for one- versus two-handed exertions were influenced by asymmetry (p < 0.001) and amplified at lower lift origin/destination heights, lower object masses and larger horizontal distances between the body and the load (p < 0.001). Practitioner summary: A biomechanical model was utilised to compare spinal loading for one versus two-handed lifting/lowering. Spinal loads in compression and A/P shear were reduced for one-handed relative to two-handed exertions. As current lifting guidelines cannot appropriately be applied to one-handed scenarios, one-handed weight limits protecting the lower back are presented herein. Abbreviations: LBD: low back disorder, EMG: electromyography, A/P: anterior/posterior, MVC: maximum voluntary contraction.


Assuntos
Mãos , Remoção , Dor Lombar/prevenção & controle , Vértebras Lombares/fisiologia , Doenças Musculoesqueléticas/prevenção & controle , Postura , Adulto , Fenômenos Biomecânicos , Eletromiografia , Feminino , Humanos , Masculino , Análise e Desempenho de Tarefas
12.
Sci Rep ; 10(1): 1635, 2020 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-32005864

RESUMO

Vertebral fractures and other back problems represent a major, increasing worldwide health problem. This has increased the need to better understand the reasons behind this phenomenon. In addition to a reduction in bone mineral density and overall size of the vertebral body, research has indicated a possible association between the shape of the endplate and spinal disorders. As one previous study has shown changes in vertebral body dimensions between contemporary people and their medieval counterparts, we wanted to examine the potential temporal trends in vertebral size and dimensions in Finnish samples of archaeological and contemporary individuals. To conduct this study, we utilized three archaeological populations from the 16th-19th century and clinical materials from two population-based Finnish birth cohorts. As the average height of people has increased greatly since the first time period, we also height-adjusted the dimensions to provide a clearer picture of the dimensional changes that have occurred in the later temporal group. Our results were in agreement with those of the earlier study. The archaeological samples had a larger vertebral size than the contemporary population when height was adjusted for. Vertebral mediolateral width in particular had decreased, and the shape of the vertebral body had changed.


Assuntos
Vértebras Lombares/fisiologia , Adulto , Arqueologia/métodos , Densidade Óssea/fisiologia , Feminino , Finlândia , Humanos , Masculino , Pessoa de Meia-Idade , Fraturas da Coluna Vertebral/fisiopatologia , Adulto Jovem
13.
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 , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Fatores de Tempo
14.
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
15.
Arch Osteoporos ; 15(1): 9, 2020 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-31897621

RESUMO

Lumbar BMD and functional recovery in the acute period were independently strongly associated with subsequent new VCF after hospital conservative therapy for patients with new fragility VCFs. Functional recovery was related with age, pain intensity during first month after hospitalization, VCF past history and multiple new VCFs. PURPOSE: This study aimed to determine the factors independently associated with the subsequent vertebral compression fracture (VCF) after hospital conservative therapy in patients with new fragility VCFs and parameters related with functional recovery in the acute period. METHODS: Subsequent VCF (n = 37) was defined as patients who sustained a new VCF within 9 months after new VCF, whereas patients without a new VCF were classified as non-subsequent VCF (n = 179). Logistic regression analysis was performed to determine independent factors associated with the subsequent VCF, including patients' characteristics, past histories, number of new VCFs, bone mineral density (BMD), lumbar sagittal alignment, fractured vertebral body height, spine muscle mass, pain intensity, corset types, medications for osteoporosis and pain relief, recovery ratio of functional independence measure (FIM) and bone union. Correlation coefficients were accessed between the FIM recovery ratio and continuous variable parameters, while intergroup comparisons or analysis of variance was conducted to examine significant differences in the FIM recovery ratio for categorical variable parameters. RESULTS: Lumbar BMD, FIM recovery ratio at the first month after hospitalization and segmental Cobb angle were significantly independently associated with subsequent VCF (odds ratio: 27.8, 9.6 and 1.1, respectively). The FIM recovery ratio was moderately negatively correlated with age and pain intensity and was significantly worse in patients with multiple new VCFs or past history of VCF. CONCLUSIONS: Conservative therapies focused on lumbar BMD, functional recovery and pain relief in the acute period may be useful in preventing subsequent VCF.


Assuntos
Tratamento Conservador/métodos , Fraturas por Compressão/etiologia , Fraturas por Osteoporose/terapia , Fraturas da Coluna Vertebral/terapia , Idoso , Idoso de 80 Anos ou mais , Densidade Óssea/fisiologia , Feminino , Fêmur/fisiologia , Fraturas por Compressão/fisiopatologia , Fraturas por Compressão/terapia , Hospitalização , Humanos , Vértebras Lombares/fisiologia , Masculino , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/complicações , Osteoporose Pós-Menopausa/fisiopatologia , Fraturas por Osteoporose/etiologia , Modalidades de Fisioterapia , Recidiva , Estudos Retrospectivos , Fatores de Risco , Fraturas da Coluna Vertebral/etiologia , Estenose Espinal/etiologia , Estenose Espinal/fisiopatologia
16.
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
17.
Spine (Phila Pa 1976) ; 45(11): E624-E630, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31972745

RESUMO

STUDY DESIGN: This is an in vitro biomechanical study. OBJECTIVES: The aim of this study was to investigate the biomechanical variations of lumbar spine motor units and that under different moments after screw heads blocking superior-adjacent bilateral facets through the cadaver specimen biomechanical experiment. SUMMARY OF BACKGROUND DATA: Facet joint violation by pedicle screws is not a rare adverse event in instrumented lumbar fusion surgery, and one of the most common types is the screw head blocking the superior-adjacent facet. However, its contribution to biomechanical instability at the supradjacent level is unknown. METHODS: The range of motion (ROM) of 12 lumbar spines (L4-S1) were measured in flexion-extension, lateral bending, and axial rotation for L4/5. All specimens were randomly divided into two groups: the control group and the blocking group, each with 6 specimens. Spine were tested on intact and instrumented specimens, respectively. The relative ROM changes were compared between the blocking and control groups. RESULTS: In the blocking group, the supradjacent-level flexion-extension ROM significantly decreased under all moments (7.5, 6.0, 4.5 Nm) relative to the intact spine and a significant decrease in the lateral bending relative ROM was found at 4.5 Nm. In the control group, no significant change of supradjacent-level ROM was found relative to the intact noninstrumented spine at each moment. When performing flexion-extension, the relative ROM change between the 2 groups was significantly different at 4.5 Nm. When performing lateral bending, the relative ROM change between the 2 groups was significantly different at moments of 6.0 and 4.5 Nm. CONCLUSION: When screw heads blocked superior-adjacent bilateral facets, the supradjacent-level flexion-extension ROM and lateral bending ROM decreased. In the long run, this may be a risk of persistent low-back pain due to frequent impingement. LEVEL OF EVIDENCE: N/A.


Assuntos
Fenômenos Biomecânicos/fisiologia , Vértebras Lombares/fisiologia , Vértebras Lombares/cirurgia , Fusão Vertebral/métodos , Articulação Zigapofisária/fisiologia , Articulação Zigapofisária/cirurgia , Idoso , Idoso de 80 Anos ou mais , Cadáver , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Parafusos Pediculares , Amplitude de Movimento Articular/fisiologia , Rotação
18.
Appl Ergon ; 84: 103021, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31987509

RESUMO

The objective of this study was to investigate biomechanical loads on the lumbar spine as a function of working in a confined vertical space, consistent with baggage handling inside the baggage compartment of an airplane. Ten male subjects performed baggage handling tasks using confined (kneeling, sitting) and unconfined (stooping) lifting styles. Dependent measures of torso flexion and three-dimensional spinal loads were assessed with an electromyography-driven biomechanical model. Lifting exertions typical to airline baggage handling posed significant risk to the lumbar spine, regardless of lifting style. Statistically significant differences attributable to lift style (stooping, kneeling, sitting) were not observed for peak compressive, lateral shear, or resultant spinal loads, but lifting while kneeling decreased anterior/posterior (A/P) shear spinal loads relative to stooping (p = 0.02). Collectively, kneeling offers the greatest benefit when lifting in confined spaces because of the ability to keep the torso upright, subsequently reducing shear forces on the lumbar spine.


Assuntos
Espaços Confinados , Vértebras Lombares/fisiologia , Postura/fisiologia , Levantamento de Peso , Adulto , Aeronaves , Fenômenos Biomecânicos , Eletromiografia , Humanos , Masculino , Esforço Físico/fisiologia
19.
Gait Posture ; 76: 389-395, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31927359

RESUMO

BACKGROUND: One in four pregnant women falls at least once during her pregnancy. During pregnancy, the body undergoes tremendous vascular, hormonal, physiological, and psychological changes to accommodate the growing fetus. The pregnancy-induced mass gain of 10 to 25 kg is not evenly distributed and results in a large change in mass distribution and shift in segmental centers of mass. To accurately understand how the change in mass distribution leads to an increase in fall events, a musculoskeletal model of the pregnant body is necessary. Generic musculoskeletal models cannot accurately represent the morphology of pregnant women and the study of postural stability of pregnant women is limited by the lack of adapted musculoskeletal models. RESEARCH QUESTION: Could a model reflecting the change in segmental inertia during pregnancy explain the pregnancy-related risk of falling? METHODS: We built a musculoskeletal model of the pregnant women, combining literature anthropomorphic measurements with generic models. We optimized the dimensions of the anthropomorphic model shapes to fit the average measurements of 25 pregnant women. The mass, center of mass, and inertia of each segment are then computed throughout pregnancy. Finally, the stance phase of a gait cycle was modeled using the pregnancy-specific and the generic models. The ankle, knee, hip and lumbar joint moments during gait were compared between the two models. RESULTS: The built musculoskeletal model of the pregnant woman includes changes in mass and geometry of the thorax, pelvis, thighs, and legs. The model reproduces the change in lumbar curvature during pregnancy. Gait simulation results show a limited impact of pregnancy on the ankle, knee, and hip moment, but a large impact on the lumbar moment. SIGNIFICANCE: Such a musculoskeletal model will help elucidate the mechanisms leading to falls or low back pain during pregnancy.


Assuntos
Articulação do Tornozelo/fisiologia , Simulação por Computador , Marcha/fisiologia , Articulação do Quadril/fisiologia , Articulação do Joelho/fisiologia , Vértebras Lombares/fisiologia , Equilíbrio Postural , Gravidez/fisiologia , Acidentes por Quedas , Fenômenos Biomecânicos , Feminino , Humanos , Pelve , Tórax
20.
Spine (Phila Pa 1976) ; 45(9): E508-E514, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31770344

RESUMO

MINI: In controls, adjacent-level range of motion (ROM) did not change relative to noninstrumented spine at each moment. In severe violation, flexion-extension and rotation ROM of adjacent vertebrae decreased at each moment (7.5, 6.0, 4.5 Nm); lateral bending ROM decreased at 4.5 Nm. Significant differences in movements were found except lateral bending (7.5 Nm). STUDY DESIGN: This is an in vitro biomechanical study. OBJECTIVES: This study aimed to investigate the biomechanical variations of lumbar spine motor units after bilateral facet joint severe violation in cadaver specimens and analyze the biomechanics under different moments. SUMMARY OF BACKGROUND DATA: The incidence of facet joint violation (FJV) is highly variable, and one of the most important factors is the lack of awareness of protection. Until now, the biomechanical effects of FJV remain unclear. METHODS: Biomechanical testing was performed on 12 human cadaveric spines under flexion-extension, lateral bending, and axial rotation loading. After intact analysis, pedicle screws were inserted at L5, and the biomechanical testing was repeated. Full range of motion (ROM) at the proximal adjacent levels under different moments was recorded and normalized to the intact (100%) noninstrumented spine. The relative ROM changes were compared between the control and severe violation groups. RESULTS: The adjacent-level ROM (flexion-extension, lateral bending, axial rotation) did not change significantly in the control group at each moment (7.5, 6.0, 4.5 Nm) compared with the intact noninstrumented spine. In the severe violation group, the supradjacent-level ROM decreased significantly under all moments relative to the intact noninstrumented spine (P < 0.05) except for the ROM of lateral bending at moments of 7.5 and 6.0 Nm. When comparing the ROM between the two groups, there were significant differences in all movements except lateral bending at 7.5 Nm. CONCLUSION: When superior-segment bilateral facet joints are severely violated by screws, the flexion-extension and axial rotation ROM of adjacent vertebrae decreases at each moment (7.5, 6.0, 4.5 Nm), and the lateral bending ROM decreases at 4.5 Nm. LEVEL OF EVIDENCE: N/A.


Assuntos
Fenômenos Biomecânicos/fisiologia , Vértebras Lombares/fisiologia , Rotação , Fusão Vertebral/métodos , Suporte de Carga/fisiologia , Idoso , Idoso de 80 Anos ou mais , Cadáver , Feminino , Humanos , Vértebras Lombares/patologia , Vértebras Lombares/cirurgia , Masculino , Pessoa de Meia-Idade , Amplitude de Movimento Articular/fisiologia , Articulação Zigapofisária/patologia , Articulação Zigapofisária/fisiologia , Articulação Zigapofisária/cirurgia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...