The stabilizing system of the spine. Part II. Neutral zone and instability hypothesis.
ABSTRACT The neutral zone is a region of intervertebral motion around the neutral posture where little resistance is offered by the passive spinal column. Several studies--in vitro cadaveric, in vivo animal, and mathematical simulations--have shown that the neutral zone is a parameter that correlates well with other parameters indicative of instability of the spinal system. It has been found to increase with injury, and possibly with degeneration, to decrease with muscle force increase across the spanned level, and also to decrease with instrumented spinal fixation. In most of these studies, the change in the neutral zone was found to be more sensitive than the change in the corresponding range of motion. The neutral zone appears to be a clinically important measure of spinal stability function. It may increase with injury to the spinal column or with weakness of the muscles, which in turn may result in spinal instability or a low-back problem. It may decrease, and may be brought within the physiological limits, by osteophyte formation, surgical fixation/fusion, and muscle strengthening. The spinal stabilizing system adjusts so that the neutral zone remains within certain physiological thresholds to avoid clinical instability.
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ABSTRACT: Clinical lumbar instability (CLI) is one of the subgroups of chronic non-specific low back pain. Thai rice farmers often have poor sustained postures during a rice planting process and start their farming at an early age. However, individual associated factors of CLI are not known and have rarely been diagnosed in low back pain. This study aimed to determine the prevalence and individual associated factors of CLI in Thai rice farmers. A cross-sectional survey was conducted among 323 Thai rice farmers in a rural area of Khon Kaen province, Thailand. Face-to-face interviews were conducted using the 13-item Delphi criteria questionnaire, after which an objective examination was performed using aberrant movement sign, painful catch sign, and prone instability test to obtain information. Individual factors such as sex, body mass index, waist-hip ratio, smoking, and number of years of farming experience, were recorded during the face-to-face interview. The prevalence of CLI in Thai rice farmers calculated by the method described in this study was 13% (age 44±10 years). Number of years of farming experience was found to be significantly correlated with the prevalence of CLI (adjusted odds ratio =2.02, 95% confidence interval =1.03-3.98, P<0.05). This study provides prevalence of CLI in Thai rice farmers. Those with long-term farming experience of at least 30 years have a greater risk of CLI.Patient Preference and Adherence 01/2015; 9:1-7. · 1.49 Impact Factor
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ABSTRACT: This report details the isolation, culture, and characterization of spinal disc stem cells derived from human adult spinal disc tissue specimens. Using stem cell suspension culture methods and biology, human adult spinal disc stem cells were isolated and monoclonally cultured into multicellular sphere-like clusters (discospheres). Discospheres from the first culture series were collected, processed, and replated as single stem cells for serial expansion studies using suspension culture, demonstrating linear expansion was possible. Discospheres and adult spinal disc stem cells were plated on matrix coated culture surfaces in stem cell media for several hours to allow fixation, and assayed for the stem cell biomarkers. Discospheres and adult spinal disc stem cells were plated on laminin-coated culture surfaces in chondrogenic media and culture conditions for 14 days to differentiate them into NP cells. NP cells cultured from these experiments demonstrated NP morphology and phenotype; NP biomarker expression, secretion of extracellular matrix, and the ability to be serially passaged with large volume expansion possible. Tissue engineering studies using the “burst kinetic assay”, demonstrated that discospheres have remarkable intrinsic developmental and tissue engineering biology that is robust and organized. In summary, adult disc stem cells and NP cells have been isolated, cultured, and characterized, from healthy spinal disc tissues. These findings demonstrate the important potential to be explored for using stem cell based tissue engineering for the treatment of degenerative disc disease (DDD).Journal of Stem Cell Research and Therapy. 12/2014; 4(11):2014.
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ABSTRACT: O objetivo deste estudo foi avaliar e classificar o nível de força de forma indireta os músculos do core em indivíduos ingressantes de academia baseados na proposta de avaliação de Kendall. A amostra foi composta por 1317 alunos ingressantes de uma academia de ginástica de São Paulo, submetidos a uma bateria de testes de avaliação física, sendo 536 do sexo masculino e 781 do sexo feminino, agrupados por faixas etárias entre 20 a 29 anos, 30 a 39 anos, 40 a 49 anos e 50 a 59 anos. Foram realizadas análises de percentual, onde o grupo total de sujeitos foi separado em diferentes amostras como gênero e idade, e comparados em relação ao percentual total dos escores obtidos no teste. Conclui-se que a grande maioria dos indivíduos não apresenta um grau adequado de força e estabilidade do core baseados na proposta de avaliação de Kendall. Palavras-chave: biomecânica, treinamento, desempenho. ABSTRACT: The objective of this study was to evaluate and classify indirectly the level of core muscle strength in beginners in a academy based on Kendall's assessment test. The sample consisted of 1317 (536 male and 781 female) beginners in a fitness facility of Sâo Paulo, submitted to Kendall's assessment test, grouped by age (20 to 29 years, 30 to 39, 40-49 years, and 50-59 years) and gender. Analysis of percentage were performed , and compared to the total percentage of the scores obtained in the test. It was concluded that the vast majority of people did not present an adequate degree of strength and core stability based on the Kendall's evaluation.Revista CPAQV. 01/2015; 7(1):1-9.