Hipotrofía nos músculos que estabilizam a coluna tem sido identificada nos pacientes com lombalgia. Entretanto, não se sabe se a perda muscular é causa ou conseqüência desta disfunção, nem se ela é influenciada pelo tipo de alteração discal que o indivíduo apresenta. Este estudo testou a hipótese de que a hipotrofía dos pacientes com lombalgia seja dependente do tipo de alteração discal. Para avaliar a condição muscular em diferentes tipos de alteração discal, optou-se por um estudo retrospectivo e por uma seleção aleatória de 78 exames de ressonância magnética de indivíduos com lombalgia. Em cada exame foram realizadas medidas quantitativas da porcentagem de gordura na área de secção transversa dos mm. multífidus e psoas, nos três últimos níveis da coluna lombar. A alteração discal foi encontrada em 95% dos exames, sendo o abaulamento o achado de imagem mais freqüente, seguido pela protrusão discal. A porcentagem de gordura variou conforme o tipo de alteração discal. Nos níveis com abaulamento há em ambos os músculos estudados 6% a mais de tecido gorduroso do que nos níveis onde há protrusão e esta diferença foi estatisticamente significante. Músculos nos níveis onde há protrusão sem fissura no anel fibroso apresentaram maior substituição gordurosa do que aqueles onde há protrusão com fissura. A porcentagem de gordura foi influenciada por características anatômicas como músculo estudado e nível da coluna, e por características como idade e sexo dos sujeitos. Estes resultados indicam que a hipotrofía muscular em pacientes com lombalgia não é um processo uniforme e generalizado, mas sim correlacionado a diferentes variáveis, entre elas o tipo de alteração discal que o paciente apresenta. / Low back pain patients present atrophy on muscles responsible for spine stabilization. However, it is not clear if muscle waste is related to the cause or if it is a consequence of this disfunction. Nor it is clear if muscle athophy is affected by the type of disc pathology. This study tested the hypothesis that muscle waste in low back pain patients influenced by the type of disc derangement. Magnetic resonance scans of 78 low back pain patients were randomly analysed. Cross sectional area percentage of fat tissue in multifidi and psoas major muscles was measured on the lower levels of the lumbar spine. Disc pathology was found in 95% of the exams and disc bulge was the most frequent abnormality, followed by disc protrusion. Fat percentage varied according to disc pathology and this difference was statistically significant. Muscles on levels with disc bulge presented 6% more fat deposits than muscles on levels with disc protrusion. Muscles on levels with discs without anular tear present more fat infiltration than muscles on levels with anular tear. Fat percentage was also influenced by anatomic aspects such as evaluated muscle and spine level, and sample characteristics as age and sex. The results indicated that muscle atrophy in low back pain patients is not a uniform and generalized feature. It is correlated to different variables, such as type of disc pathology

Hipotrofía nos músculos que estabilizam a coluna tem sido identificada nos pacientes com lombalgia. Entretanto, não se sabe se a perda muscular é causa ou conseqüência desta disfunção, nem se ela é influenciada pelo tipo de alteração discal que o indivíduo apresenta. Este estudo testou a hipótese de que a hipotrofía dos pacientes com lombalgia seja dependente do tipo de alteração discal. Para avaliar a condição muscular em diferentes tipos de alteração discal, optou-se por um estudo retrospectivo e por uma seleção aleatória de 78 exames de ressonância magnética de indivíduos com lombalgia. Em cada exame foram realizadas medidas quantitativas da porcentagem de gordura na área de secção transversa dos mm. multífidus e psoas, nos três últimos níveis da coluna lombar. A alteração discal foi encontrada em 95% dos exames, sendo o abaulamento o achado de imagem mais freqüente, seguido pela protrusão discal. A porcentagem de gordura variou conforme o tipo de alteração discal. Nos níveis com abaulamento há em ambos os músculos estudados 6% a mais de tecido gorduroso do que nos níveis onde há protrusão e esta diferença foi estatisticamente significante. Músculos nos níveis onde há protrusão sem fissura no anel fibroso apresentaram maior substituição gordurosa do que aqueles onde há protrusão com fissura. A porcentagem de gordura foi influenciada por características anatômicas como músculo estudado e nível da coluna, e por características como idade e sexo dos sujeitos. Estes resultados indicam que a hipotrofía muscular em pacientes com lombalgia não é um processo uniforme e generalizado, mas sim correlacionado a diferentes variáveis, entre elas o tipo de alteração discal que o paciente apresenta. / Low back pain patients present atrophy on muscles responsible for spine stabilization. However, it is not clear if muscle waste is related to the cause or if it is a consequence of this disfunction. Nor it is clear if muscle athophy is affected by the type of disc pathology. This study tested the hypothesis that muscle waste in low back pain patients influenced by the type of disc derangement. Magnetic resonance scans of 78 low back pain patients were randomly analysed. Cross sectional area percentage of fat tissue in multifidi and psoas major muscles was measured on the lower levels of the lumbar spine. Disc pathology was found in 95% of the exams and disc bulge was the most frequent abnormality, followed by disc protrusion. Fat percentage varied according to disc pathology and this difference was statistically significant. Muscles on levels with disc bulge presented 6% more fat deposits than muscles on levels with disc protrusion. Muscles on levels with discs without anular tear present more fat infiltration than muscles on levels with anular tear. Fat percentage was also influenced by anatomic aspects such as evaluated muscle and spine level, and sample characteristics as age and sex. The results indicated that muscle atrophy in low back pain patients is not a uniform and generalized feature. It is correlated to different variables, such as type of disc pathology

by Chan Kwai Foon May. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 103-114). / Abstracts in English and Chinese. / Declaration --- p.2 / Abstract --- p.3 / Abstract in Chinese --- p.6 / Acknowledgements --- p.8 / Chapter Chapter 1. --- Introduction --- p.15 / Chapter Chapter 2. --- Osteoporosis : The relationship between aging and skeletal organization between men and women --- p.17 / Chapter 2.1. --- Skeletal organization --- p.17 / Chapter 2.1.1. --- Bone structure --- p.17 / Chapter 2.1.2. --- Bone metabolism --- p.17 / Chapter 2.1.3. --- Peak bone mass --- p.18 / Chapter 2.2. --- Bone loss between men and women --- p.20 / Chapter 2.2.1. --- Aging and bone loss --- p.20 / Chapter 2.2.2. --- Clinical aspects of bone loss in men and women --- p.21 / Chapter Chapter 3. --- Vertebral deformity : Bone Mineral Density and Body Composition --- p.23 / Chapter 3.1. --- Bone mineral density --- p.23 / Chapter 3.1.1. --- Types of vertebral deformity --- p.23 / Chapter 3.1.2. --- Clinical diagnosis in vertebral deformity --- p.24 / Chapter 3.1.3. --- Bone mineral density measurements --- p.25 / Chapter 3.1.4. --- Vertebral deformity and bone mineral density --- p.28 / Chapter 3.2. --- Bone composition --- p.33 / Chapter Chapter 4. --- Literature Review on Health Consequences of Vertebral Deformity --- p.36 / Chapter 4.1. --- Back pain --- p.36 / Chapter 4.1.1. --- Back pain and vertebral deformity --- p.36 / Chapter 4.1.2. --- Back pain in men and women with vertebral deformity --- p.38 / Chapter 4.2. --- Morale and functional limitation and vertebral deformities --- p.39 / Chapter 4.2.1. --- Function evaluation : The Barthel Index --- p.40 / Chapter 4.2.2. --- Philadelphia Geriatric Morale Scale --- p.41 / Chapter Chapter 5. --- Objectives --- p.43 / Chapter Chapter 6. --- "Subjects and methods for phase I: anthropometric measurement, body composition and bone mineral density measurement in vertebral deformity patients and controls" --- p.44 / Chapter 6.1. --- Study subjects --- p.44 / Chapter 6.2. --- Radiology and digitization protocol for diagnosis vertebral deformity --- p.46 / Chapter 6.3. --- Diagnosis of vertebral deformity --- p.48 / Chapter 6.4. --- Body composition and bone mineral density measurements --- p.54 / Chapter 6.4.1. --- Body composition analysis --- p.54 / Chapter 6.4.2. --- Lumbar spine and hip bone mineral analysis --- p.54 / Chapter 6.5. --- Quality control --- p.56 / Chapter 6.5.1. --- Routine quality control of measurements --- p.56 / Chapter 6.5.2. --- Precision on patient repositioning --- p.56 / Chapter Chapter 7. --- Subjects and methods for phase II: health consequences of vertebral deformity patients and controls --- p.57 / Chapter 7.1. --- Questionnaire on health consequences --- p.57 / Chapter 7.1.1 --- Back pain and disability --- p.57 / Chapter 7.1.2 --- Activities of daily living --- p.59 / Chapter 7.1.3 --- Morale --- p.59 / Chapter 7.2. --- Statistical methods --- p.60 / Chapter 7.2.1. --- Bone mineral density and body composition --- p.60 / Chapter 7.2.2. --- Back pain and disability --- p.60 / Chapter 7.2.3. --- Activities of daily living and morale --- p.61 / Chapter Chapter 8. --- "Results for phase I: anthropometric measurement, body composition and bone mineral density measurement in vertebral deformity patients and controls" --- p.62 / Chapter 8.1. --- Demographic characteristics of study population --- p.62 / Chapter 8.2. --- Anthropometric measurements : Body composition and bone mineral density --- p.64 / Chapter Chapter 9. --- Results for phase II: Health Consequences of vertebral deformity patients and control --- p.76 / Chapter 9.1. --- Back pain --- p.76 / Chapter 9.2. --- Disability --- p.78 / Chapter 9.3. --- Activities of daily living --- p.81 / Chapter 9.4. --- Morale --- p.82 / Chapter Chapter 10. --- Discussion I --- p.83 / Chapter 10.1. --- Study Sample --- p.83 / Chapter 10.2. --- Digitization method and definition of vertebral deformity --- p.84 / Chapter 10.3. --- Methods for bone mineral density measurement --- p.87 / Chapter 10.4. --- Questionnaire validity --- p.88 / Chapter 10.4.1. --- Back pain and disability --- p.88 / Chapter 10.4.2. --- Barthel Index --- p.88 / Chapter 10.4.3. --- Philadelphia Geriatric Morale Scale --- p.89 / Chapter Chapter 11. --- Discussion II --- p.92 / Chapter 11.1 . --- Body composition and bone mineral density --- p.92 / Chapter 11.2. --- Differences of vertebral deformity between Chinese men and Caucasian men --- p.93 / Chapter 11.3. --- Health consequences in Chinese men --- p.96 / Chapter 11.4. --- Comparison of health consequences between Chinese men and Caucasian men --- p.98 / Chapter 11.5. --- Variation of health consequences between Chinese men and Chinese women --- p.101 / Chapter 11.5.1. --- Back pain and disability --- p.101 / Chapter 11.5.2. --- Morale --- p.102 / Chapter Chapter 12. --- Conclusion --- p.103 / Reference --- p.104 / Appendix I --- p.115 / Appendix II Publication