| Objectives: The purposes of the present study are as follows:(1)To build a 3D motions analyzing system. (2)To evaluate the biomechanical stability of a lumbar with pedicle screw system named GSS. (3) Ascertain whether augmentation pedicle screw fixation with PMMA bone cement can enhance the stability of unstable thoracolumer burst fractures of osteoporotic spine. (4)10 provide the researching foundation for the system of spinal sursgery visualization. Methods: (I) SPINE2000 3D Motions Analyzing System using the theory of stereo vision based on computer image processing and visual c++ in WINDOWS. (2)12 lumbar spine speclinems (L2桳5), obtained from fresh human cadavers, were divided into two groups, A and B. All intact specimens were subjected to nondestructive testing in 6 loading modalities on a universal testing machine. A cadaveric model of complete L2桳5 instability was produced following a wedge fracture of body with release of the posterior Iigamentous structures in both groups. Specimens in group A were stabilized with GSS, and group B with SOCON pedicle screw. The nondestructive testing was repeated to determine structural stability.(3) 6 fresh frozen old females?osteoporotic spines (T10-L5) were harvested and L1 were defect to create an anterior and posterior column unstable model. Each specimen was fixated with plate and testing were performed in flexion extension ,axial rotation ,and lateral bending directions. Testing of fatigue experiments were done on MIS 858. Testing were repeated after screws had augmented with PMMA. To observe the screws loosening and the change of stiffness after fatigue, and to compare the biomechanical stability of different conditions: a)normal specimens, b)defect model fixated with plate,not augmented and not fatigue, c)after fatigue,not augmented, d)screws were augmented with PMMA, not fatigue, e) after augmented and fatigue. (4) Comparing volume rendering with surface rendering is discussed both in rendering quality and time consuming.Two methods of surface rendering namely Point-based and Polygon-based used in the system are introduced. The Syetem of Spinal Surgery Visualization is developed. Results: (1)A spinal three-dimensional measurement system was developed based on computer ?? stereo vision. The maximum deviations of marks in 60 X 60 X 150mm3 between measureing value and caculating value wree 0.4mm,0.7mm, 0.2mm and 0.6mm, 0.8mm, 0.3mm along X, Y and Z axis repectively.(2) The injured spines stabilized with implants in both groups were significantly more stable than the intact specimens in all modes of testing (P<0.05). Stability of injured spines was increased the most in flexion-extension, 62.8% in flexion and 63.9 % in extension by GSS while 54.9% in flexion and 51.0% in extension by SOCON. The two constructs provided similar stability in 6 loading modalities (P>O.05).(3) At 6 directions, the stability of 6 specimens have no significant difference in b ,d ,e conditions (P>0.05), and significantly stronger than a ,c conditions (P<0.0 1). After fatigue ,there were 19 of 24 screws had loosened and stiffness had decreased significantly (P<0.000) in c condition, while there were no change when screws had augmented with PMMA.(4) 3D spinal model of ct image is reconstructed. Conclusion: (1)3D Spinal Motions Analyzing System has been applicated in clinical and has achived excellent results. (2)This study shows that GSS provides biomechanical stability for...
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