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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Passive Stiffness Characteristics of the Scoliotic Lumbar Torso in Trunk Flexion, Extension, Lateral bending, and Axial Rotation

Voinier, Steven 08 May 2015 (has links)
As the average American age increases, there is a need to study the spine biomechanics of adults with scoliosis. Most studies examining the mechanics of scoliosis have focused on in vitro testing or computer simulations, but in vivo testing of the mechanical response of a scoliotic spine has not yet been reported. The purpose of this study was to quantitatively define the passive stiffness properties of the in vivo scoliotic spine in three principle anatomical motions and identify differences relative to healthy controls. Scoliotic (n=14) and control (n=17) participants with no history of spondylolisthesis, spinal fracture, or spinal surgery participated in three different tests (torso lateral side bending, torso axial rotation, and torso flexion/extension) that isolated mobility to the in vivo lumbar spine. Scoliotic individuals with Cobb angles ranging 15-75 degrees were accepted. Applied torque was measured using a uni-directional load cell, and inertial measurement units (IMU) recorded angular displacement of the upper torso relative to the pelvis and lower extremities. Torque-rotational displacement data were fit using a double sigmoid function, resulting in excellent overall fit (R2 > 0.901). The neutral zone (NZ) width, or the range of motion where there is minimal internal resistance, was then calculated. Stiffnesses within the NZ and outside of the NZ were also calculated. Stiffness asymmetries were also computed within each trial. These parameters were statistically compared between factor of population and within factor of direction. There was an interaction effect between populations when comparing axial twist NZ width and lateral bend NZ width. The lateral bend NZ width magnitude was significantly smaller in scoliotic patients. NZ stiffness in the all three directions was greater in the scoliotic population. There was no significant difference in asymmetrical stiffness between populations. The present study is the first investigation to quantify the in vivo neutral zone and related mechanics of the scoliotic lumbar spine. Future research is needed to determine if the measured lumbar spine mechanical characteristics can help explain progression of scoliosis and complement scoliosis classification systems. / Master of Science
22

Komparace velikosti skoliotické křivky pacientů s idiopatickou skoliózou z RTG snímku a záznamu rastrovací stereografie / Comparison of the size of scoliosis curve in patients with idiopathic scoliosis from x-ray picture and rasterstereography record

Bilinkiewiczová, Eva January 2016 (has links)
Scoliosis is defined as a patological curvature of spinal cord of more than 10ř in frontal plane which is combined with rotation of vertebral bodies and also with disruption of fyziological curvatures in sagittal plane. Idiopathic scoliosis is the most frequent type of this diagnosis. The thesis deals with overal issue of this disease, theories of etiology, incidence, classification, types of examination, possibilities of new testing and therapy. The practical part describes rasterstereographic DIERS Formetric III 4D testing and coparison with RTG examination. The study was carried out with 17 girls and 1 boy with idiopathic scoliosis 11 - 46ř at the age of 11 - 17 years. Results of this testing were statistically analysed. Best results were found out in measurements by automatically set range for a group of patients with Cobb angle ≤ 25ř - for 95% differences the limits of correspondance were ± 4ř, the average error was 0,3ř. For group of all patients the limits of correspondance were ± 14ř, the average error was 1,5ř. The results confirmed, that with an increase of Cobb ange a bigger error and systematic error appears.
23

A multi-scale study of bone mineralization and bone quality in adolescent idiopathic scoliosis / CUHK electronic theses & dissertations collection

January 2015 (has links)
Introduction. The etiology of adolescent idiopathic scoliosis (AIS) is largely unknown. AIS was well-documented to be associated with low bone mineral density (BMD) and abnormal bone quality. We hypothesized that bone matrix mineralization is abnormally low in AIS and that the abnormality could lead to the observed osteopenia and abnormal bone quality that might contribute to the etiopathogenesis of AIS. / Objectives. 1. To verify the abnormal bone mass and bone quality in AIS Vs normal matched controls 2. To study the bone matrix mineralization status, micro-architecture and mechanical property in AIS Vs controls 3. To study the cellular and molecular characterization of bone formation and resorption in AIS Vs controls 4. To study the possible association of abnormal bone quality with the curve progression / Methods. 1. The case-control study in Chapter 3 included 257 AIS and 187 age- and gender-matched normal controls. BMD and bone quality were measured with dual-energy X-ray absorptiometry (DXA) and high-resolution peripheral quantitative computed tomography (HR-pQCT) in vivo. 2. Chapter 4 studied iliac crest bone biopsies from 28 AIS and 9 controls. Bone mineral status was measured with DXA, micro-computed tomography (micro-CT) and energy dispersive X-ray spectroscopy; bone micro-architecture and mechanical property were measured with micro-CT, individual trabeculae segmentation analysis and finite element analysis (FEA). 3. Chapter 5 included 46 AIS and 23 controls. The mRNA expression of the bone tissue and primary osteoblastic and osteoclastic activities related to bone mineralization were studied. 4. Chapter 6 included 82 AIS patients. Bone quality was measured with HR-pQCT in vivo at baseline. Comparison was made between the stable and the progressive patients followed for more than 1.5 years after skeletal maturity. / Results. 1. In Chapter 3, both osteopenic and non-osteopenic AIS had lower areal BMD (aBMD) and trabecular and cortical volumetric BMD (vBMD) than their matched normal controls, with the non-osteopenic AIS reaching statistical significance (P<0.05). Osteopenic AIS had larger cortical perimeter and trabecular area than the osteopenic controls after adjustments of confounding factors (P<0.05); non-osteopenic AIS had significantly lower cortical area, thickness and vBMD than the non-osteopenic controls (P<0.05), and marginally significant cortical area and thickness after adjustments. 2. In Chapter 4, AIS had lower bone calcium content (Ca/C ratio) in trabecular bone than controls (P<0.05); moreover, AIS had significantly lower trabeculae rod number and thickness and mechanical property (P<0.05). Osteopenic AIS had significantly lower rod and plate micro-architecture (P<0.05) and 11.3% of decline of FEA mechanical property than non-osteopenic AIS. 3. In Chapter 5, AIS had lower expression of osteogenic markers (ALP and RUNX2) (P=0.009-0.132) and higher expression of extracellular matrix markers (COL1 and BGLAP) (P =0.109-0.132) in bone formation, and higher expression of bone resorption markers (TRAP and CTSK) (P =0.045-0.100). AIS also showed lower osteogenic differentiation potential and calcium nodule formation ability than controls. Within the subgroups, osteopenic AIS showed lower osteoblastic differentiation (P=0.009) and 41.8% decline of calcium formation abilities (P =0.186). The primary osteoblasts from the osteopenic AIS had higher pro-osteoclastogenic potential (P =0.034) and higher osteoclastogenic differentiation potential on osteoclasts. 4. In Chapter 6, progressive AIS had significantly lower aBMD, total vBMD and lower cortical area and thickness after adjustments (P<0.05). The predictive model showed that bone quality model was more predictive than the aBMD model which was more predictive than the basic model on curve progression. / Discussions The present study verified all the AIS had lower BMD and abnormal bone quality. It provided a direct evidence of lower calcium content in AIS which might contribute to the observed lower BMD. Therefore, these abnormalities in AIS could represent a spectrum of severity which is labeled as osteopenic or non-osteopenic with DXA and partly explained by the cellular and molecular studies. The longitudinal study showed AIS with poorer bone quality have significantly higher probability of curve progression. In summary, the present findings supported and confirmed our proposed hypothesis. / 引言:有研究提示AIS低骨量與骨質量異常與病因學有關。我們推測,AIS的骨基質礦化可能異常降低,進而導致低骨量和異常骨質量發生,這可能與AIS病因学有關。 / 目的:1. 驗證AIS的低骨量及骨質量異常 2. 调查AIS骨基質礦化、骨微結構和機械性能狀態 3. 研究AIS關於骨礦化的細胞分子功能 4. 探讨AIS骨質量與側彎進展間的關聯 / 方法:1. 通過雙能吸收儀和高分辨率外周定量CT比较低骨量和非低骨量AIS与其正常對照間骨密度和骨質量的差异 2. 通過雙能吸收儀、顯微CT和掃描電鏡與能量色散光譜儀檢測骨礦物質含量,及顯微CT、骨小梁個體分割和有限元分析法檢測骨微結構和力學性能,比較AIS和正常對照及AIS亞組間的差異。3. 通過檢測與骨礦化相關的mRNA,和原代成骨和破骨細胞培養,比較AIS和正常對照及AIS亞組間的差異。4. 通過高分辨率外周定量CT縱向隨診AIS患者,比較進展組和穩定組間骨質量差異。 / 結果:1. 低骨量和非低骨量AIS均比正常對照組骨密度和骨質量降低。2. AIS骨鈣含量降低,骨微結構和機械性能顯著異常。3. AIS骨形成標記物降低、骨吸收標記物升高,成骨分化潛能降低。低骨量AIS比非低骨量AIS成骨細胞分化能力降低和親破骨分化潛能升高。4. 側彎進展AIS骨密度和骨質量顯著異常。 / 討論:本研究結果支持我們的假設:AIS骨基質礦化異常,導致低骨量和異常骨質量,提示與AIS發病機理相關聯。 / Wang, Zhiwei. / Thesis Ph.D. Chinese University of Hong Kong 2015. / Includes bibliographical references (leaves 243-261). / Abstracts also in Chinese; appendixes includes Chinese. / Title from PDF title page (viewed on 09, September, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.
24

A study of bone mineral profile: bone mineral density, bone turnover and genetic marker in AIS.

January 2000 (has links)
Cheung Siu-king. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves [103-113]). / Abstracts in English and Chinese. / ACKNOWLEDGMENT --- p.i / TABLE OF CONTENTS --- p.ii / LIST OF ABBREVIATIONS --- p.vi / LIST OF TABLES --- p.vi / LIST OF FIGURES --- p.ix / ABSTRACT (ENGLISH VERSION) --- p.x / ABSTRACT (CHINESE VERSION) --- p.xii / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1. --- ADOLESCENT IDIOPATHIC SCOLIOSIS --- p.1 / Chapter 1.1.1. --- prevalence and geographic patterns of ais --- p.1 / Chapter 1.1.2. --- CLINICAL ASPECTS OF AIS --- p.3 / Chapter 1.1.3. --- ETIOLOGY OF AIS --- p.8 / Chapter 1.2. --- OBJECTIVES OF THIS STUDY --- p.24 / Chapter 2. --- SUBJECTS AND METHODS --- p.25 / Chapter 2.1. --- STUDY DESIGN --- p.25 / Chapter 2.2. --- SUBJECTS RECRUITMENT --- p.25 / Chapter 2.2.1. --- ais subjects --- p.25 / Chapter 2.2.2. --- control subjects --- p.25 / Chapter 2.2.3. --- GROUPING ACCORDING TO THE CHRONOLOGICAL AGE --- p.26 / Chapter 2.2.4. --- informed Consent --- p.26 / Chapter 2.2.5. --- EVALUATION OF COBB'S ANGLE --- p.26 / Chapter 2.3. --- ANTHROPOMETRIC ASSESSMENTS --- p.26 / Chapter 2.4. --- BMD MEASUREMENTS --- p.28 / Chapter 2.4.1. --- measured by dexa --- p.28 / Chapter 2.4.2. --- measured by pqct --- p.30 / Chapter 2.5. --- BONE FORMATION MARKER : BALP --- p.32 / Chapter 2.5.1. --- SERUM COLLECTION --- p.32 / Chapter 2.5.2. --- ABBOTT METHODS FOR SERUM ALP ACTIVITY --- p.32 / Chapter 2.6. --- BONE RESORPTION MARKER : DPD --- p.34 / Chapter 2.6.1. --- PYRILINK-D KITS REAGENT --- p.34 / Chapter 2.6.2. --- CREATININE ASSAY --- p.34 / Chapter 2.7. --- GENETIC MARKER - POLYMORPHISM OF ESTROGEN RECEPTOR GENE --- p.38 / Chapter 2.7.1. --- DIGESTION OF PERIPHERAL BLOOD CELLS --- p.38 / Chapter 2.7.2. --- QUANTITATION OF DNA --- p.39 / Chapter 2.7.3. --- CONFIRMATION OF INTEGRITY OF DNA --- p.39 / Chapter 2.7.4. --- POLYMERASE CHAIN REACTION (PCR) --- p.39 / Chapter 2.7.5. --- REACTION BUFFER --- p.39 / Chapter 2.8. --- STATISTICS --- p.45 / Chapter 3. --- RESULTS --- p.46 / Chapter 3 .1 --- SUBJECT DISTRIBUTION OF AIS AND NORMAL CONTROL --- p.46 / Chapter 3.1.1. --- "mean ages of menarche, breast development and pubic hair development" --- p.47 / Chapter 3.1.2. --- "PUBERTAL STATUES OF DIFFERENT AGE GROUPS EVALUATED BY MENARCHE, BREAST DEVELOPMENT AND PUBIC HAIR DEVELOPMENT" --- p.48 / Chapter 3.2. --- ANTHROPOMETRIC ASSESSMENTS --- p.49 / Chapter 3.2.1. --- OVERALL REVIEW OF ANTHROPOMETRIC ASSESSMENTS --- p.49 / Chapter 3.2.2. --- ANTHROPOMETRIC ASSESSMENTS ACCORDING TO THE CHRONOLOGICAL AGE --- p.50 / Chapter 3.3. --- BMD PROFILE OF AIS PATIENTS --- p.51 / Chapter 3.3.1. --- ABMD MEASURED BY DEXA (OVERALL REVIEW) --- p.51 / Chapter 3.3.2. --- ABMD IN DIFFERENT AGE GROUPS --- p.52 / Chapter 3.3.3. --- VBMD MEASURED BY PQCT (OVERALL REVIEW) --- p.52 / Chapter 3.3.4. --- VBMD IN DIFFERENT AGE GROUPS --- p.53 / Chapter 3.3.5. --- PREVALENCE OF OSTEOPENIA IN AIS PATIENTS --- p.53 / Chapter 3.3.6. --- SYMMETRY OF BILATERAL PROXIMAL FEMUR AND DISTAL TIBIA … --- p.54 / Chapter 3.3.7. --- CORRELATION OF ABMD AND VBMD WITH ANTHROPOMETRIC PARAMETERS AND SPINAL DEFORMITY --- p.54 / Chapter 3.4. --- BONE FORMATION MARKER- BALP --- p.55 / Chapter 3.5. --- BONE RESORPTION MARKER -DPD --- p.56 / Chapter 3.6. --- GENETIC MARKER -ESTROGEN RECEPTOR GENE --- p.57 / Chapter 4 --- DISCUSSION…… --- p.84 / Chapter 4.1 --- BONE MINERAL DENSITY OF AIS PATIENTS --- p.84 / Chapter 4.2 --- ANTHROPOMETRIC MEASUREMENTS --- p.89 / Chapter 4.3 --- BONE BIOCHEMICAL TURNOVER MARKER --- p.91 / Chapter 4.4 --- GENETIC MARKER - ER GENE --- p.97 / Chapter 4.4.1 --- OSTEOPORTIC CANDIDATE GENE- ER GENE --- p.98 / Chapter 4.4.2 --- NO CORRELATION BETWEEN ER GENE AND AIS --- p.99 / Chapter 4.5 --- SUMMARY --- p.100 / Chapter 5. --- CONCLUSION --- p.101 / BIBLIOGRAPHY --- p.XIV / APPENDIX --- p.XXV
25

Curve progression in adolescent idiopathic scoliosis: is osteopenia a new and valid prognostic factor?.

January 2004 (has links)
Hung Wing Yin Vivian. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 128-142). / Abstracts in English and Chinese ; appendix in Chinese. / ABSTRACT --- p.i / ABSTRACT (in Chinese) --- p.iv / ACKNOWLEDGMENT --- p.vii / TABLE OF CONTENTS --- p.viii / LIST OF TABLES --- p.xiv / LIST OF FIGURES --- p.xvi / LIST OF ABBREVIATIONS --- p.xix / Chapter I. --- INTRODUCTION --- p.1 / Chapter 1.1. --- Scoliosis --- p.1 / Chapter 1.1.1. --- Classification of scoliosis --- p.1 / Chapter 1.1.2. --- Idiopathic scoliosis --- p.1 / Chapter 1.1.3. --- Clinical examination --- p.2 / Chapter 1.1.4. --- Curve pattern --- p.2 / Chapter 1.2. --- Etiology of AIS --- p.3 / Chapter 1.2.1. --- Prevalence of AIS --- p.5 / Chapter 1.2.2. --- Anthropometric Measurement in AIS --- p.5 / Chapter 1.2.3. --- Bone mass --- p.6 / Chapter 1.2.4. --- Bone mineral density measurements --- p.6 / Chapter 1.2.5. --- Osteopenia in AIS --- p.7 / Chapter 1.3. --- Natural history ofAIS --- p.8 / Chapter 1.3.1. --- Curve progression --- p.9 / Chapter 1.3.2. --- Treatment of scoliosis --- p.11 / Chapter 1.4. --- Research questions --- p.12 / Chapter 1.5. --- Objectives --- p.13 / Chapter II. --- METHODOLOGY --- p.20 / Chapter 2.1 --- Study Design --- p.20 / Chapter 2.2 --- Subject recruitment --- p.20 / Chapter 2.2.1 --- AIS patients --- p.20 / Chapter 2.2.2 --- Inclusion criteria --- p.20 / Chapter 2.2.3 --- Exclusion criteria --- p.20 / Chapter 2.2.4 --- Informed consent --- p.21 / Chapter 2.3 --- Grouping for chronological age --- p.21 / Chapter 2.4 --- Radiography assessments --- p.21 / Chapter 2.4.1 --- Cobb angle measurement --- p.21 / Chapter 2.4.2 --- Curve pattern --- p.22 / Chapter 2.4.3 --- Risser grade --- p.22 / Chapter 2.5 --- Definition of curve progression --- p.22 / Chapter 2.6 --- Bone mineral density (BMD) measurements --- p.23 / Chapter 2.6.1 --- Dual energy X-ray Absorptiometry (DXA) --- p.23 / Chapter 2.6.2 --- Peripheral quantitative computed tomography (pQCT) --- p.24 / Chapter 2.6.3 --- Definition of osteopenia or low bone mass --- p.24 / Chapter 2.7 --- Anthropometric measurements --- p.25 / Chapter 2.7.1 --- Body height --- p.25 / Chapter 2.7.2 --- Body weight --- p.26 / Chapter 2.7.3 --- Arm span --- p.26 / Chapter 2.7.4 --- Sitting height --- p.27 / Chapter 2.8 --- Family history --- p.27 / Chapter 2.9 --- Menstrual status --- p.27 / Chapter 2.10 --- Medication and fracture history --- p.27 / Chapter 2.11 --- Statistical analysis --- p.27 / Chapter 2.11.1 --- Sample size power calculation --- p.28 / Chapter 2.11.2 --- Student t test --- p.28 / Chapter 2.11.3 --- Paired t-test --- p.28 / Chapter 2.11.4 --- Predicting the incidence of curve progression --- p.28 / Chapter 2.11.4.1 --- Predictive outcome --- p.28 / Chapter 2.11.4.2 --- Potential risk factors --- p.28 / Chapter 2.11.4.3 --- Coding system for categorical variables --- p.29 / Chapter 2.11.4.4 --- Univariate analysis --- p.30 / Chapter 2.11.4.5 --- Logistic regression --- p.30 / Chapter 2.11.4.6 --- Receiver operating characteristics (ROC) curves --- p.32 / Chapter III. --- RESULTS --- p.54 / Chapter 3.1 --- Patients Characteristics --- p.54 / Chapter 3.1.1 --- Sample size --- p.54 / Chapter 3.1.2 --- Distribution of patient characteristics --- p.54 / Chapter 3.1.3 --- Drop out --- p.54 / Chapter 3.1.4 --- Prevalence of osteopenia (BMDage-adjusted ≤ -1) and low bone mass (BMCage-adjusted ≤ -1) --- p.55 / Chapter 3.1.5 --- Comparison between the BMD of the bilateral hip and tibia --- p.55 / Chapter 3.2 --- Comparison of AIS patients with osteopenia and with normal bone status --- p.55 / Chapter 3.3 --- Univariate analysis --- p.56 / Chapter 3.3.1 --- Growth related factors --- p.56 / Chapter 3.3.2 --- "Skeletal related parameters (areal BMD, volumetric BMD and BMC)" --- p.56 / Chapter 3.3.2.1 --- DXA lumbar spine --- p.56 / Chapter 3.3.2.2 --- DXA proximal femur at the convex-side hip --- p.56 / Chapter 3.3.2.3 --- DXA proximal femur at the concave-side hip --- p.57 / Chapter 3.3.2.4 --- pQCT at non-dominant distal radius --- p.57 / Chapter 3.3.2.5 --- pQCT - vBMD at convex-side distal tibia --- p.57 / Chapter 3.3.2.6 --- pQCT - vBMD at concave-side distal tibia --- p.58 / Chapter 3.3.3 --- Curve related factors --- p.58 / Chapter 3.3.4 --- Anthropometrics parameters --- p.58 / Chapter 3.3.5 --- Family history --- p.58 / Chapter 3.3.6 --- Summary of univariate analysis --- p.59 / Chapter 3.4 --- Logistic regression model (single factor) --- p.59 / Chapter 3.5 --- Logistic regression model (multiple factors) --- p.60 / Chapter 3.5.1 --- BMD inclusive model --- p.60 / Chapter 3.5.2 --- BMC inclusive model --- p.61 / Chapter 3.5.3 --- Conventional model --- p.63 / Chapter 3.6 --- ROC curve --- p.63 / Chapter 3.6.1 --- BMD inclusive model --- p.64 / Chapter 3.6.2 --- Conventional model --- p.64 / Chapter 3.7 --- Predictive equation obtained from different logistic regression models --- p.64 / Chapter 3.7.1 --- BMD inclusive model --- p.65 / Chapter 3.7.2 --- Conventional model --- p.65 / Chapter IV. --- DISCUSSION --- p.105 / Chapter 4.1 --- Prognostic factors for curve progression --- p.105 / Chapter 4.1.1 --- Well-known prognostic factors --- p.105 / Chapter 4.1.1.1 --- Growth-related factors --- p.106 / Chapter 4.1.1.2 --- Initial curve magnitude --- p.107 / Chapter 4.1.2 --- A new predictor 一 Osteopenia --- p.107 / Chapter 4.2 --- Non-significant prognostic factors for curve progression --- p.109 / Chapter 4.2.1 --- Anthropometric parameters --- p.109 / Chapter 4.2.2 --- Family History --- p.110 / Chapter 4.2.3 --- Curve pattern --- p.110 / Chapter 4.3 --- Predictive model --- p.111 / Chapter 4.4 --- Comparison of predictive models between BMD inclusive model and conventional model derived from our population --- p.115 / Chapter 4.5 --- Possible relationship between osteopenia and etiopathogensis of AIS --- p.116 / Chapter 4.6 --- Axial measurement has a better predictive power in curve progression than peripheral measurement --- p.117 / Chapter 4.7 --- Discordance of BMD in bilateral hips --- p.118 / Chapter 4.8 --- Method justifications --- p.119 / Chapter 4.8.1 --- Definition of curve progression --- p.119 / Chapter 4.8.2 --- Incidence of progression as the outcome of prediction --- p.119 / Chapter 4.8.3 --- Selection on bone densitometers --- p.119 / Chapter 4.9 --- Clinical significance --- p.121 / Chapter 4.10 --- Limitations and Future Studies --- p.122 / Chapter 4.10.1 --- Limited follow-up time --- p.122 / Chapter 4.10.2 --- No defined cutoff value for 226}0´ببosteopenia 226}0ح or low BMC in paediatric area --- p.122 / Chapter 4.10.3 --- Predictive model could only applied in local population --- p.122 / Chapter 4.10.4 --- Intrinsic error in Risser grade measurement --- p.123 / Chapter 4.10.5 --- Further studies --- p.123 / Chapter 4.10.5.1 --- Validation of the newly developed predictive model --- p.123 / Chapter 4.10.5.2 --- Possible intervention of osteopenia --- p.124 / Chapter 4.10.5.3 --- Long term follow-up BMD measurements and fracture risk in AIS patients --- p.124 / Chapter 4.10.5.4 --- Discordance of bilateral hips BMD contributed by the shift of center of gravity --- p.125 / Chapter 4.10.5.5 --- Axial QCT can be an alternative method in assessing BMDin scoliotic patients --- p.125 / Chapter V. --- CONCLUSION --- p.126 / Chapter VI. --- APPENDIX --- p.127 / Chapter VII. --- BIBLIOGRAPHY --- p.128 / Chapter VIII. --- CONFERENCE PUBLICATIONS --- p.142
26

Asynchronous neuro-osseous growth in adolescent idiopathic scoliosis associated with anatomical changes: new approach with morphological and functional magnetic resonance imaging studies. / CUHK electronic theses & dissertations collection

January 2007 (has links)
For the nervous system, there is evidence of relative shortening of the spinal cord, reflected by both reduced cord length to vertebral column ratio and a change in cross-sectional morphology of the cord. The cerebellar tonsils are low-lying in AIS subjects while significant regional volume differences in the brain are also evident between AIS subjects and controls. / From the results of this series of study, AIS girls are found to have morphological difference in multiple aspects when compared with age- and sex-matched normal controls. / Idiopathic scoliosis is a common worldwide problem and has been treated for many decades; however, there still remain uncertain areas about this disorder. Its involvement and impact on different parts of the human body remain underestimated due to lack of technology in imaging for objective assessment in the past. / In the skeletal system, AIS girls have generalized osteopenia and abnormal growth of the appendiceal skeleton. For the axial skeleton, abnormal ossification patterns have been found affecting both the longitudinal growth and axial growth pattern of the vertebral column. There is overgrowth of the anterior vertebral column, reversed asymmetry of the neural arch and smaller pedicle at the concavity of the scoliotic curve in AIS, suggestive of asynchronous growth between membraneous and endochondral ossifications. In the skull, both calvarium and basicranium are found have regional difference (including foramen magnum) between AIS subjects and controls, which is again probably reflecting a systemic process of asynchronous growth between membraneous and endochondral ossification. / It was concluded that the hypothesis "In adolescent idiopathic scoliosis, advanced magnetic resonance imaging techniques can be used to identify systemic features which are suggestive of asynchronous neuro-osseous growth of the disorder" was confirmed. (Abstract shortened by UMI.) / Taking together, the abnormalities in the skeletal system and nervous system are likely to be inter-related and reflecting a systemic process of asynchronous neuro-osseous growth. The above findings help to explain a number of well documented neurological abnormalities in AIS: Anatomically, there is increased incidence of Chiari malformation and syringomyelia in AIS subjects, while functionally, abnormal somatosensory evoked potential (SSEP) results, impaired postural balance, poor performance on combined visual and proprioceptive testing and spatial orientation testing as well as reports of abnormal nystagmus response to caloric testing are known to be associated with AIS. / The advances in imaging technique and image analysis technology have provided a novel approach for the understanding of the phenotypic presentation of neuro-osseous changes in AIS subjects as compared with normal controls. Dynamic imaging also assists in functional assessment of pulmonary function and respiratory mechanism in AIS subjects. / The hypothesis to be tested in this series of studies is: "In adolescent idiopathic scoliosis, advanced magnetic resonance imaging techniques can be used to identify systemic features which are suggestive of asynchronous neuro-osseous growth of the disorder". This thesis was based on a series of eight studies which were aimed to explore the "unknown" anatomical features in the skeletal and neural systems in AIS by the application of new advanced technique of MR imaging and sophisticated image analysis programs. / We are the first group who has undertaken a comprehensive morphological assessment of the skeletal and nervous systems in AIS subjects based on imaging findings which have not been reported previously. For the first time in literature, the spinal cord and vertebral column, brain and skull were thoroughly analyzed in AIS subjects and compared with age- and sex-matched normal controls. Detailed correlations with clinical information, neurological tests have also been made. As an appendix, MR imaging findings of the pulmonary system in AIS, including the lung, chest wall and diaphragms are also presented at the end of the thesis. / Chu Chiu-wing, Winnie. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 0976. / Thesis (M.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 248-267). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / School code: 1307.
27

The relationship of leptin and leptin bioavailability with body composition, bone quality and osteoblast functions in adolescent idiopathic scoliosis.

January 2014 (has links)
引言: 青少年突發性脊柱側彎(Adolescent Idiopathic Scoliosis, AIS)是一種複雜的脊柱三維畸形,而目前病因未明。這病主要出現於11-14歲的青少年女性,罹患率約為四個百分比。未經治療的側彎可能逐漸加重並導致明顯的外觀畸形,嚴重者可導致心肺功能異常等其他併發症。目前對AIS的治療方法包括觀察,支具和手術內固定矯形。然而因為這些治療並非針對病因而仍然存在一定缺陷,如支具治療失敗和手術的併發症等。因此明確AIS的發病機制仍然是制定有效治療的關鍵。 / 根據過往研究報告,AIS患者有低體重、身形高大、臂展增加、低體重指數,月經初潮推遲與低骨量,這顯示AIS患者或有全身性生長異常。因為瘦素的重要生理功能如影響骨骼發育、開始青春期,能量消耗和身體成分,所以瘦素被假設為AIS的病因之一。之前的研究報告指出,AIS患者對比相同年齡和性別的人擁有較低水平的循環瘦素。然而,瘦素信號的強度不僅由瘦素水平所決定的,它也有可能受到可溶性瘦素受體(sOB-R)所影響。sOB-R是循環系統中瘦素的結合蛋白,可以調節血清瘦素水平,並影響對目標組織的生物活性游離瘦素之生物利用度。游離瘦素指數(FLI)的開發是為了幫助數據的詮釋,並提供游離瘦素水平的估計。 / 瘦素對骨代謝的影響是間接地由中央神經系統和直接地由周緣組織來施加的。瘦素被發現通過下丘腦神經系統對骨形成有分解效果。而瘦素的周緣作用被證實對骨形成有直接的合成作用,例如促進成骨細胞和軟骨細胞的增殖,刺激成骨細胞的分化和礦化,及抑制破骨細胞的生長和活性。根據先前對AIS患者的骨髓間充質幹細胞(MSCs)之研究,AIS患者對瘦素有較低的反應和在成脂和成骨幹細胞有較低的瘦素受體。這提供了在AIS患者的骨細胞和瘦素相關異常的初步證據。 / 當前研究的目的是: / 1)通過測量在AIS患者和正常對照組的血清總瘦素,sOB-R和FLI的水平來調查AIS患者是否有任何異常的游離瘦素生物利用度,及是否和異常的人體測量參數有關聯。 / 2)通過研究AIS患者和對照組之身體成分及與血清總瘦素,sOB-R和FLI的相互關係來調查游離瘦素生物利用度與AIS患者與對照組之關聯。 / 3)通過利用高分辨率周邊定量電腦斷層來研究與AIS患者與對照組的骨質量差異及與血清總瘦素,sOB-R和FLI的相互關系來調查游離瘦素生物利用度與AIS患者與對照組之關聯。 / 4)通過研究AIS患者與對照組對瘦素與成骨細胞增殖,分化和礦化的影響, 與成骨細胞上的瘦素受體來調查AIS患者是否對瘦素有異常反應和瘦素受體的異常表現。 / 方法: 1)游離瘦素的生物利用度和人體測量參數的研究包括了207名AIS女孩和155名年齡和性別匹配的正常對照組。因超重/肥胖者有比較高的血清瘦素水平,為避免來自於超重/肥胖者的影響,身體質量指數(BMI)大於23.0的實驗對象被排除。評估包括人體和性成熟的測量:如體重、身高、臂展、坐高,體重指數和坦納階段。血清總瘦素和sOB-R水平測定採用ELISA法,而游離瘦素指數(FLI)的計算為總血清瘦素/sOB-R的比值。 / 2)游離瘦素的生物利用度和身體成分的研究包括了148名AIS女孩和116名正常對照。身體成分的評估採用了生物電阻抗分析(BIA)。 / 3)游離瘦素的生物利用度和骨質量參數的研究包括了207名AIS女孩和155名正常對照。非優勢的遠端橈骨質量以高分辨率周邊定量電腦斷層(HR-pQCT)進行評估。體內骨骼強度以有限元分析(FEA)進行了評估。 / 4)對成骨細胞功能反應和瘦素受體表達的研究包括了12名接受矯正脊椎手術的AIS女孩和6名接受與側彎無關之手術的對照組。成骨細胞是從手術中拿取的骨活檢中分離,並進行培養和評估瘦素對細胞增殖,分化和礦化的影響(0,10,100,1000毫微克/毫升),而分別採用MTT法,鹼性磷酸酶活性測定, 骨鈣素酶聯免疫吸附和von Kossa染色。瘦素受體(LEP-R)在基礎和成骨條件下的蛋白表達以Western blot檢測來進行AIS和對照組之間的比較。 / 結果: 1)在游離瘦素的生物利用度和人體測量參數的研究中,AIS女孩在調整了年齡和體重後有較高的sOB-R和較低的FLI,也和較低的體重和較低的BMI有關聯。AIS女孩還有在血清總瘦素,FLI和人體測量參數之間顯著較弱的相關性。 / 2)在游離瘦素的生物利用度和身體成分的研究中,AIS女孩有較低的骨骼肌質量,較低的身體脂肪和較低的身體脂肪百分比,以及在血清總瘦素,FLI和所有身體成分參數之間較弱的相關性。 / 3)在游離瘦素的生物利用度和骨質量的研究中,AIS女孩有較低的皮質體積骨密度,較低的骨小梁數量,較高的骨小梁分離度以及更高的結構模型指數(SMI)。在相關性分析中, AIS女孩在血清總瘦素和FLI與骨小梁參數的相關性有特殊的相關模式,這相關性沒有在正常對照組中出現。 / 4)在對成骨細胞的功能反應和瘦素受體的表達之研究中,對照組隨瘦素濃度升高而有增加的代謝信號,然而,AIS組沒有對瘦素出現增殖反應。在第六天和第十四天的分化實驗中,對照組的鹼性磷酸酶活性隨著瘦素濃度升高而表現出清晰而強烈的趨勢,而AIS組的鹼性磷酸酶活性沒有出現趨勢也沒有顯著差異。在骨鈣素酶聯免疫吸附實驗中, 對照組隨著瘦素濃度升高而表現出清晰而強烈的趨勢, 而AIS組沒有出現顯著差異。在礦化實驗中,對照組隨瘦素濃度升高而呈輕度上升的礦化趨勢, AIS組再次地沒有出現趨勢和差異。在基礎和成骨條件下, 瘦素受體的表達並沒有出現顯著差異。 / 討論:這是對AIS中瘦素的生物利用度與身體成分和骨質量之關係的第一個研究。本研究的結果表示,AIS女孩可能存在異常的游離瘦素生物利用度,並可能導致異常表型,例如較低的BMI,異常的身體成分和較差的骨質量。低骨量在AIS中的重要性和骨小梁參數與血清總瘦素和FLI的不正常的關係,使我們進一步研究瘦素對AIS的成骨細胞的影響。當與對照組相比,來自AIS女孩的成骨細胞對瘦素有非常低的反應。這異常反應可能是由於瘦素信號轉導途徑的功能障礙,其中可能包括異常的瘦素受體和下游信號分子。這是一個重要的發現,並可能有助於解釋與AIS相關的低骨量和較差的骨質量。這項研究提供了AIS發病機理的新見解和新的研究方向。未來的研究不妨包括瘦素信號轉導途徑中可能受到AIS影響的下游信號分子和動物模型來證實瘦素和瘦素生物利用度與AIS之間的因果關係。總而言之,這一系列的研究結果表示了瘦素和瘦素生物利用度在骨骼發育、體格,骨骼質量和AIS的發病機制中的重要性。 / Introduction: Adolescent idiopathic scoliosis (AIS) is a complex three-dimensional structural deformity of the spine and its etiology remains unknown. It mainly occurs in girls between 11 to 14 years old with a prevalence rate of 4%. This common spinal deformity can be associated with significant cosmetic, psychological, and clinical morbidities in severe cases. Current treatments for AIS are unsatisfactory, mainly because they are merely treating the phenotype of the spinal deformity but not the underlying etiology. Therefore, it is crucial to understand the etiopathogenesis of AIS so that effective therapeutic and preventive measures can be devised. / Previous studies have reported the association between AIS and low body weight, tall stature, increased arm span, low body mass index, delayed onset of menarche and low bone mass, which indicated abnormal systemic growth in patients with AIS. Leptin has been postulated as one of the etiologic factors of AIS because of its important physiological functions in neuro-osseous development affecting skeletal growth, the onset of puberty, energy expenditure and body composition. A previous study had reported lower circulating leptin in AIS girls than age- and sex-matched controls. However, the strength of leptin signal is not only determined by the leptin level, it could also be affected by soluble leptin receptor (sOB-R), its binding protein in circulation. sOB-R could modulate the serum leptin level, and affect the bioavailability of free leptin, the biologically active form, to its target tissues. Free leptin index (FLI) was developed to aid interpretation of data and provide an estimation of free leptin level. / The effects of leptin on bone metabolism are exerted indirectly through the central nervous system and directly on the peripheral tissues. Leptin was shown to have a catabolic effect on bone formation through the hypothalamus and the sympathetic nervous system (SNS). While the peripheral effects of leptin was shown to be anabolic to bone formation, promoting the proliferation of osteoblasts and chondrocytes, stimulating osteoblastic differentiation, mineralization, and inhibiting osteoclastogenesis and osteoclast activity. With regards to AIS, a previous study on bone marrow derived mesenchymal stem cells (MSCs) showed lower responses to leptin, and lower leptin receptor expressions in adipogenic and osteogenic MSCs. This study provided initial evidence that leptin related pathways might be abnormal in the bone cells of AIS patients. / This study aimed to: / 1) Investigate if there is any abnormality in free leptin bioavailability by measuring the serum total leptin, sOB-R levels, and FLI in AIS and control subjects, and if it is associated with abnormal anthropometric parameters in AIS. / 2) Investigate if free leptin bioavailability in AIS is associated with abnormal body composition by studying the difference in body composition and its correlations with serum total leptin, sOB-R, and FLI between AIS and control subjects. / 3) Investigate if free leptin bioavailability in AIS is associated with abnormal bone quality by studying the difference in bone quality as measured by high resolution pQCT and its correlations with serum total leptin, sOB-R, and FLI between AIS and control subjects. / 4) Investigate if there are abnormal functional responses to leptin and abnormal expression of leptin receptor in AIS by determining the effects of leptin on proliferation, differentiation, and mineralization of osteoblasts; and the expression levels of leptin receptor in osteoblasts isolated from intra-operative bone biopsies of AIS and control subjects. / Methods: 1) The study on free leptin bioavailability and anthropometric parameters included 207 AIS girls and 155 age- and gender-matched normal controls. Subjects with body mass index (BMI)>23.0 were excluded to avoid bias from the relatively high serum leptin level in overweight / obese subjects. Assessments included anthropometric and sexual maturity measurements: body weight, height, arm span, sitting height, BMI, and Tanner stages. Serum total leptin and sOB-R levels were measured with ELISA, and free leptin index (FLI) was calculated as the ratio of serum total leptin / sOB-R. / 2) The study on free leptin bioavailability and body composition included 148 AIS girls and 116 normal controls, while anthropometric and sexual maturity parameters included 207 AIS girls and 155 normal controls. Body composition was assessed with bioelectrical impedance analysis (BIA). / 3) The study on free leptin bioavailability and bone quality parameters included 207 AIS girls and 155 normal controls. Bone quality on the non-dominant distal radius was assessed with high resolution pQCT (HR-pQCT). In vivo bone strength was assessed with finite element analysis (FEA). / 4) The study on functional responses and leptin receptor expression in osteoblasts included 12 AIS girls undergoing corrective spinal surgery and 6 control subjects undergoing unrelated surgery. Primary osteoblasts were isolated from intra-operative bone biopsies, and were cultured and assessed for the effects of leptin (0, 10, 100, 1000 ng/mL) on cell proliferation, differentiation, and mineralization by MTT assay, alkaline phosphatase activity assay and osteocalcin ELISA, and von Kossa staining respectively. Protein expressions of leptin receptor (LEP-R) under basal and osteogenic conditions were compared between AIS and controls by Western blot. / Results: 1) In the study on free leptin bioavailability and anthropometric parameters, AIS girls had higher sOB-R and lower FLI after adjusting for age and body weight, and these were associated with lower body weight and lower BMI. Significant correlation between serum total leptin and sOB-R was found in controls, but no correlation was observed in AIS girls. AIS girls also showed markedly weaker correlations between serum total leptin, FLI, and anthropometric parameters. / 2) In the study on free leptin bioavailability and body composition, AIS girls had lower skeletal muscle mass, lower body fat, and percentage body fat, as well as weaker correlations between serum total leptin, FLI, and all body composition parameters. / 3) In the study on free leptin bioavailability and bone quality, AIS girls had lower cortical volumetric bone mineral density (vBMD), lower trabecular number, higher trabecular separation, and higher structural model index (SMI) value. In correlation analysis with serum total leptin and FLI, AIS girls had distinctive correlation pattern with trabecular bone parameters that was not observed in the normal controls. / 4) In the study on functional responses and leptin receptor expression in osteoblasts, control group showed increasing MTT signals to leptin in a dose dependent manner, while AIS group showed no proliferative response to leptin. For differentiation, control group showed strong and significant trend in ALP activity to increasing leptin concentrations in both day 6 and 14, but this trend was not observed in the AIS group. Osteoblasts from the control group secreted osteocalcin in an increasing dose dependent manner to leptin, but AIS group showed weak responses to leptin. For mineralization, the control group showed a mild increasing trend to increasing leptin concentrations, and again no trend was observed in the AIS group. No significant differences in the expression of leptin receptor under basal and osteogenic conditions were found between AIS and control group. / Discussion: This is the first study on the relationship of leptin bioavailability with body composition and bone quality in AIS. The results in this study suggested that abnormal free leptin bioavailability might exist in AIS girls and could lead to abnormal phenotypes such as lower BMI, abnormal body composition, and deranged bone quality that often manifested in AIS simultaneously. The importance of low bone mass in AIS and the presence of correlations between trabecular bone parameters and serum total leptin and FLI which were not observed in controls, have led us to further investigate the effects of leptin on primary osteoblasts in AIS. The osteoblasts isolated from AIS girls had no or very low response to leptin when compared with controls, which was shown to be independent of the difference in leptin receptor expression levels. This lack of response might be due to dysfunction of leptin signaling pathway, which might include structural or binding abnormalities in the leptin receptor or downstream signal molecules. This is an important finding and might serve to explain the low bone mass and deranged bone quality that is associated with AIS. This study provided new insights and new research directions on the etiopathogenesis of AIS. Future research could include studies on the downstream signal molecules along the leptin pathways that might be affected in AIS, and animal models to confirm the causal relationship of leptin and leptin bioavailability to AIS. In summary, the findings in this series of studies demonstrated the importance of leptin and leptin bioavailability in skeletal growth, body build, bone quality, and the etiopathogenesis of AIS. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Tam, Man Shan Elisa. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 259-301). / Abstracts also in Chinese; appendixes includes Chinese.
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Effects of adherence to bracing treatment in children with adolescent idiopathic scoliosis: a preliminary study

Ichinoe, Abraham 08 April 2016 (has links)
OBJECTIVE: The objective of this study is to determine the different biological, psychological, and social factors that affect patient adherence in bracing treatment for adolescent idiopathic scoliosis. By comparing adherent and non-adherent bracing patients, we hope to gain insight into how to improve patient adherence in bracing as a means of primary treatment and to avoid secondary and tertiary treatments such as surgery. METHODS: Of the 19 patients (15 adherent, 4 non-adherent) who were examined for this study, the majority of them completed all psychosocial surveys at one time point in their bracing treatment. Patients answered surveys for multidimensional anxiety, generalized anxiety, pain-related fear and avoidance, pain catastrophizing, and quality of life. Quantitative sensory testing was performed on only 5 of the 19 patients at the time of writing. Sensory testing was conducted to gather information on thermal sensitivities and thresholds. Statistical t-test significance was determined for all surveys distributed to adherent and non-adherent bracing groups, and scaled T-scores were calculated for each survey measure to determine clinical significance. RESULTS: There were no statistically significant differences in any measures examined between adherent and non-adherent bracing patients. The only statistically significant difference was the number of hours of brace wearing, with the adherent group wearing their brace over 11 hours more than the non-adherent group (p < 0.0004). CONCLUSIONS: Because of the underpowered nature of this study, measures for multidimensional anxiety, generalized anxiety, pain-related fear and avoidance, pain catastrophizing, and quality of life should be reexamined for potential differences between adherent and non-adherent bracing patients. Quantitative sensory testing should be included as a measure of possible sensory differences between the two groups. A future study with a larger sample size may provide greater understanding into the motivations for bracing adherence in an effort to help patients avoid more invasive means of intervention in treating adolescent idiopathic scoliosis.
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Escoliose idiopática do adolescente: estudo familiar para identificação de regiões cromossômicas ligadas à sua etiologia / Familial study of the genes location related to adolescent idiopathic scoliosis

Wajchenberg, Marcelo [UNIFESP] 26 May 2010 (has links) (PDF)
Made available in DSpace on 2015-07-22T20:50:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-05-26. Added 1 bitstream(s) on 2015-08-11T03:26:19Z : No. of bitstreams: 1 Publico-140.pdf: 1558335 bytes, checksum: f630d19bbd2da038c706fccd9f88d5f9 (MD5) / Introdução: A escoliose idiopática do adolescente é uma das doenças infantis mais freqüentes, no entanto a sua etiologia permanece desconhecida. Estudos familiares são realizados na tentativa de mapear uma região cromossômica ligada a esta doença. Objetivos: Estudar os aspectos genéticos e pesquisar regiões cromossômicas relacionadas à escoliose idiopática do adolescente em uma família brasileira com múltiplos membros afetados Métodos: Avaliamos 56 membros, distribuídos em quatro gerações, de uma família brasileira com nove indivíduos portadores de escoliose idiopática do adolescente. A probanda apresentava curva escoliótica de 75 graus, mensurada pelo método Cobb. O critério para caracterização como afetado pela doença foi a presença de uma radiografia frontal, em ortostáse, demonstrando curva maior do que 15 graus. Após a assinatura do Termo de Consentimento Livre e Esclarecido, os indivíduos foram submetidos à coleta de sangue periférico para extração de DNA genômico e subsequente análise de ligação, utilizando marcadores microssatélites pertencentes à ABI PRISM® Linkage Mapping Set Version 2 (Applied Biosystems). Resultados: Não foi possível localizar uma região cromossômica ligada à escoliose idiopática do adolescente, na família estudada. Conclusão: Não foi possível, por meio do estudo de ligação genética, encontrar uma região cromossômica responsável pela escoliose idiopática do adolescente, ao analisar quatro gerações de uma família brasileira, com múltiplos membros afetados. / Introduction: The etiology of idiopathic scoliosis remains unknown and different factors have been suggested as causal. Hereditary factors can also determine the etiology of the disease; however, the pattern of inheritance remains unknown. Other studies have suggested possible chromosome regions related to the etiology of idiopathic scoliosis. Objetive: To study the genetic aspects and investigate chromosome regions for adolescent idiopathic scoliosis in a Brazilian family. Methods: Evaluation of 56 family members, distributed over 4 generations of a Brazilian family, with 9 carriers of adolescent idiopathic scoliosis. The proband presented a scoliotic curve of 75 degrees, as determined by the Cobb method. Genomic DNA from family members was genotyped. Results: Locating a chromosome region linked to adolescent idiopathic scoliosis was not possible in the family studied. Conclusion: While it was not possible to determine a chromosome region responsible for adolescent idiopathic scoliosis by investigation of genetic linkage using microsatellites markers during analysis of four generations of a Brazilian family with multiple affected members. / TEDE / BV UNIFESP: Teses e dissertações
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A Proof of Concept for a Machine Learning Algorithm to Screen for Adolescent Idiopathic Scoliosis Using Images Captured with Modern Smartphone Technology

Wenghofer, Jessica 19 September 2022 (has links)
Adolescent idiopathic scoliosis (AIS) is an extremely common three-dimensional (3-D) deformity of the spine, affecting the population between 10 and 18 years of age. Early detection of AIS is critical, as the earlier that the spinal deformity can be identified, the more likely it is that curve progression can be minimized or arrested using conservative treatment options. However, today much of the responsibility for detecting AIS falls on untrained parents. Therefore, the purpose of this thesis project is to use images taken with a smartphone containing a depth sensor to create a simple and effective machine learning (ML) algorithm that can detect the absence or presence of scoliosis. Secondarily, this thesis project aims to 1) provide a proof of concept for a regression-based ML algorithm that can predict the main curvature of the scoliotic spine and 2) to determine if the depth information from the smartphone contains additional features or information that can improve the performance of the ML algorithm when compared to regular red-green-blue (RGB) images. Thirty-three participants (28 AIS; 5 Control) were recruited from the Children’s Hospital of Eastern Ontario (CHEO). Images of the unclothed backs of participants were taken with a smartphone (Samsung S20 Ultra 5G) containing a depth sensor, while participants assumed two positions: an upright standing posterior-anterior (PA; mirroring the position participants are in when getting an EOS scan) and a forward bending position. A convolutional-neural-network (CNN)-backed decision tree algorithm was developed and trained using three different data streams: a red-green-blue-depth (RGB-D), a Colourized depth map, and an RGB data stream. It was determined that the model trained with the Colourized forward bending images had the highest overall accuracy. The CNN backed decision tree was able to classify images of participants in a forward bend posture with an accuracy of 93%, specificity of 75%, and a sensitivity of 99%. Additionally, it was found that all algorithms trained with the varying data streams were able to predict the Cobb angle of the spine within 16° of the ground truth Cobb angles. The lowest root mean square error (RMSE) values were obtained from the RGB images when the participants were in the PA position. The PA RGB dataset had RMSE values of 7.17° between the ground truth and predicted Cobb angles. Inter-rater reliability errors typically range between 5-7° for manually measured Cobb angles. Therefore, given the calculated RMSE for the PA RGB dataset were close to this range, there is the potential to use this smartphone technology to screen for scoliosis and predict the curvature of the spine (Morrison et al., 2015). While these results are promising, the dataset is small compared to other studies; therefore, this thesis provides a proof of concept, and more work needs to be done to increase the robustness of the model and to further improve the ability of the model to predict the Cobb angle of the spine.

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