| Summary: | 博士 === 國立成功大學 === 生物醫學工程學系 === 101 === Low back disorders are common illness in our daily life as well as in clinical practice worldwide. According to the investigations of the council of Labor Affairs of the Executive Yuan, it is acknowledged that 65-80% of the population in Taiwan could experience low back disorders at least once throughout their life time. More than 60% of patients with low back disorders would develop recurrent symptoms within two years, while for 2-3% of patients, their symptoms could last at least half a year, and they could even become disabled. Challenges have existed in making diagnoses of low back disorders from pathologic perspectives. The main reasons are the complexity of the pathology as well as the variation in patients’ symptoms. In addition, several diagnostic tools have been shown to vary in their sensitivity and specificity. The observations of the clinical symptoms may not always be related to the results of imaging tests.
Patients with low back disorders can develop self-limiting movements in their daily life activities in order to avoid discomfort in their movements. It is important to discuss the degree of self-limiting movements which occur in patients and which hopefully could be identified as the severity of back injuries. The outcomes and level of recovery could be further classified. From past studies, the functional assessments of low back disorders have been limited to several kinds: self-reported questionnaires, range of motion measurements, muscle strength testing, or time measurements of daily movements. Due to the complexity of the anatomy and the movement patterns of the lumbar spine, challenges exist in the current measurement tools.
This current study is pioneering in its use of the concept of functional workspace to evaluate the trunk mobility of patients with low back disorders, and is expected to help classify and diagnose injuries. The major work of this project includes three parts:
The first part: As reported in the chapter three, the current study used a computer-assisted motion analysis system to measure the kinematics and the functional workspace of the low back. This study established the functional workspace from healthy young subjects and identified the consistency of the trunk circumduction. The results of this study indicate that the movement of trunk circumduction measured by motion analysis instruments is a reliable tool. The intra-class correlation coefficient (ICC) value is 0.90-0.96, and the means and standard deviations of the normalized workspace are: C7 0.425 (0.116); L1 0.843 (0.297); and knee 0.014 (0.011). Little correlation between the maximal displacements of trunk circumduction and those of straight planes in the cardinal planes is shown, suggesting that different movement patterns exist. This study demonstrates the high statistical reliability of the functional workspace of trunk circumduction (FWTC), which is important for its potential development as a functional assessment tool. The FWTC provides a single integrated value to represent angular and linear measurements of different joints and planes. Future study is expected to carry out FWTC to evaluate the amount of workspace for the functional status of patients with low back injuries or patients who have undergone spinal surgery.
The second part: In the chapter four, comparisons of workspace are made between the patients with low back disorders and age-matched healthy subjects by using a computer-assisted motion analysis system. The daily quality of low back disorders was measured by the Oswestry Disability Index (ODI). The associations between functional workspace and the ODI results are discussed for the patients with low back disorders. The results indicate that the FWTC measured by motion analysis instruments could differentiate between age-matched healthy subjects and patients with low back disorders. Significant differences of workspace are shown between the healthy subjects and the patients with low back disorders. The correlations coefficients for patients with spondylolisthesis between the workspace and the ODI were high. The functional workspace has been further established as a useful tool for identifying the injuries of low back disorders by association with ODI.
The third part: before we start to use surface markers to represent the bony movements, the first step is to establish the relationships between the surface markers and the bony landmarks. We used conventional X-rays to identify the positions between the surface markers and the bony landmarks in sidelying positions of the spine. A total of 37 patients with low back disorders participated in this study and five surface markers were used to adhere the spinous processes of the lumbar spine. The geometric equation estimates the position differences compared with the position of the surface markers and projecting vertebral body centers on the surface. The distance between the markers and the projecting vertebral body centers was the greatest at L1 35.9mm and the smallest at L4 15.1 mm. The geometric characteristics of the lumbar spine affected the distance at different levels, with the R2 values from 0.66- 0.89, except for 0.38 at the L4 level. Increases in the spinous process inclination as well as vertebral inclinations, and increases in the spinous process height were factors that were found to be significantly related to the SP-PVBC distance (p〈0.05). The results indicate that the motional analysis by measuring the pathway of the surface markers cannot demonstrate the intervertebral motions. Future study of motion analysis may effectively assess the movement of the selective region instead of intervertebral motions.
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