The Aging Study Of Caiqiao Manipulation Based On A Three Dimensional Finite Model Of Lumbar Segments

Objective:Constructed healthy (normal) and lumbar disc herniation (patient) three-dimensional finite element model of L1?S1 segments, observed the biomechanical effect(stress and strain) of different aging parameters(cycle and length) of Caiqiao manipulation on L1?S1 whole section and L4?L5 functional units of the spine biomechanics,explored aging mechanisms, optimized the aging parameters, explored aging difference of Caiqiao manipulation on normal and patients,provided objective basis for mechanism and optimization study of Caiqiao treating LDH.Methods:(1)Used the GE Discovery MR 750 3.0 T MRI scanner to obtain normal and patient MRI images of lumbar spine, established L1?S1 segment 3D finite element model by Patran,Mimics,Geomagic,Nastran finite element software.loaded static axial compression from 250N to 1500N on L4?5 segment, compared with the same boundary experimental biomechanical study to verify material parameter.we used the bed lumbar partial pressure device to obtain MRI images of 0kgf,144kgf and real-time 20S dynamic, verified the validity of models by comparing the "Cobb Angle" (the Angle of the edge of L2?5 edge extension)of L1?S1 finite element model and MRI images.(2) Simulated dynamic mechanical loading on both sides of the vertical longitudinal axis and coronal plane into 90 degrees,5cm besides L4?5 vertebral pace to simulate Luo Caigui professor's Caiqiao manipulation by computer imulation data of actual data. Simulated 12 kinds of Caiqiao aging condition containing six cycles and six lengths. The cycle conditions were 0.89S,1.25S,1.5S, 1.8S,2.25S,3.25S, the 1.25S was actual cycle of professor luo; the length conditions were 10S?20S?30S?40S?50S?60S, the 20S was actual length of professor luo. Compared the relative displacement between intervertebral disc and nerve roots of L4-5 finite element model and cobb angle under different working conditions of normal and patient. The stress was compared on L4?5 intervertebral disc.nerve root,vertebral body, zygapophysial joints in optimal frequency and length of normal and patient. As the same,the displacement and cobb angle changing rate(the maximum relative displacement) were compared on the same conditions.Results:(1) The normal and patient 3D FEM of L1?S1 segments were established by our study, the normal included 106242 physical units,98 line units,27453 nodes;120277 physical units,124 line units,31193 nodes on patient. The FEM contained non-linear and geometric non-linear. In the same load, the compression-axial displacement curve was quite near the changes by other biomechanical experiments. In the 0kgf,144kgf and real-time 30S dynamic load, the changes on cobb angle of 3D FEM and the MRI images were compared, the differences had no statistically significance both normal and patient (P>0.05).(2) On the six kinds of cycle conditions:(2.1) All conditions can obviously increased the relative displacement and the Cobb Angle, the displacement curve under B was the most stable, the normal average relative displacement was greater than the patient. (2.2) The Cobb Angle analysis of maximum relative displacement point:compared B group with other groups, the differences had no statistically significance on C.F group(.P>0.05), had statistically significance on A.D.E group(P<0.05) in normal; the differences had statistically significance on A, C, D, E, F group (P<0.05) in patient. (2.3) The cycle comparison on the relative displacement:compared B group with other groups the differences had no statistically significance (P>0.05) in normal;the differences had statistically significance (P<0.05) in patient.(3) On the six kinds of length conditions:(3.1) The relative displacement curves appeared a certain rule for 20S both normal and patients. (3.2) The maximum relative displacement point Cobb Angle analysis:compared B group with other groups, the differences had statistically significance(P<0.05)in normal; the difference had statistically significance on A group (P<0.05), had no statistically significance on C, D, E, F group (P>0.05)in patient. (3.3) The relative displacement analysis:compared B group with other groups, the differences had no statistically significance (P>0.05) both normal and patient.(4) We made the stress analysis on the best cycle and lenth:(4.1) The stress focus on the disc,the upper and lower edges of the vertebral body,nerve root, the articular process joint stress is small. (4.2) The intervertebral disc stress analysis:the differences had statistically significance on inter group comparison beween normal and patient (P<0.05), intra-group comparison both normal and patient (P<0.05); (4.3) The nerve root stress analysis:the differences had statistically significance on inter group comparison beween normal and patient (P<0.05),intra-group comparison both normal and patient (P<0.05); (4.4) The L4 lower edge and L5 upper edge stress analysis:the differences had statistically significance on inter-group comparison beween normal and patient (P<0.05),intra-group comparison both normal and patient (P<0.05); (4.5) The zygapophysial joints stress analysis:the differences had statistically significance on inter-group comparisons(P<0.05); the differences had no statistically significance on intra-group comparison in L4 inferior articular process (P>0.05);the differences had statistically significance on L5 superior articular process intra-group comparison in patient (P<0.05).(5)The strain analysis:(5.1) The differences had no statistically significance on intervertebral disc average displacement (P>0.05); (5.2) The differences had statistically significance on nerve root average displacement (P<0.001); (5.3) The differences had statistically significance on relative displacement (P<0.001); (5.4) The differences had statistically significance on the changing rate of cobb angle of the maximum relative displacement(P<0.001).Conclusion:(1) The 3D FEM of L1-S1 segments had a good effect of simulation. It can manifest the anatomy and biomechanical properties. It was qualified to be used in biomechanical research on aging parameters of Caiqiao manipulation.(2) The 12 kinds of aging conditions had increased lumbar curvature, relative displacement of L4?5 segments nerve root and disc, one of the biological effects for Caiqiao treating LDH was lumbar curvature and nerve root compression improved.(3) The operation was safe and effective on cycle 1.25S, length 20S of the 12 kinds of aging condition, it was the optimal paramete for Caiqiao treating LDH.(4) The stress was different on L4-5 segment of normal and patient, the articular process joint stress was smaller than the disc, the edges of vertebral body,nerve root. The stress of patient was not "average",the compliance and stability of lumbar spine mechanics has reduced.(5) The lumbar curvature change rate and relative displacement of normal were greater than patient, The strain of patient was not "deep penetration", the compliance and coordination of lumbar spine mechanics has reduced.