Research And Development Of Lumbar Vertebrae Analysis System

Lumbar vertebrae are the key position of torso activity. Under the external force, pathology changes usually follow the degeneration of lumbar speeded up by the advance of age and excessive activity or loads. Lumbar spine instability and spondylolisthesis are the common lumbar degenerative disease. With the advances in computer technology and medicine, digitalized video fluoroscopy (DVF) has been widely used in clinical research due to the advantage of continuous low-dose imaging. This paper proposed a new development of measurement system, which can be applied to spine kinematic analysis, called Vertebrae Analysis System (VAS) based on biomechanical studies of spinal column and particle filter. The VAS can automatically track the vertebrae edges in the DVF sequence initialized by placing control points on the first frame.In the performance assessment with anatomical lambo-sacral model, all of the ICC (Intraclass Correlation Coefficient) of Test-Retest Reliability and the comparison analysis with the results from actual measurement were greater than 0.8, and the outcome was of strong correlation. The maximum fiducial error was 3.7% and the repeatability error was 1.2% in translation and the maximal repeatability error was 2.6% in rotation angle. In the performance assessment with simulated sequence, the maximal difference was 1.3 mm in translation and 1°in rotation angle. The error was small in x-and y-translation (fiducial error:2.4%, repeatability error:0.5%) as well as in rotation angle (fiducial error:1.0%, repeatability error:0.7%). The VAS could still track the edges of vertebrae over sequence contaminated by noise with the density≤0.5. The results demonstrated that VAS was of strong robustness and exact accuracy.In the clinical trial with in vivo study, we recruited healthy 17 subjects for control group and 15 patients with lumbar degenerative disease as patient group. The kinematic parameters, such as range of motion, translation and angle of rotation, linear velocity and angular velocity, linear acceleration and angular acceleration, intervertebral translation and intervertebral angle, were analyzed contrastively. We found that there was statistical significance (P≤0.05) between both groups in range of motion of L4 and L5 in x-translation. In patient group, prolonged deflections were found usually at L4. the statistical differences of average and maximum were significant (P≤0.05) in x-linear velocity at L4, in intervertebral translation in y direction and intervertebral angle between L4 and L5.In summary, the regions of lesions about lumbar degenerative disease could be accurately and quantitatively measured by this new developed system. Through statistical analysis, the difference was significant in the segments prone to get lumbar degenerative disease between control group and patient group. The VAS presented a good reliability and robustness. It demonstrates that the analysis results from the proposed system have a potential value in the evaluation of spinal medical application as an objective basis for clinical diagnosis.