Quantitative Study Of The Force And Analyze With Finite Element Of Lumbar Spinal Manipulation

Objective (1)To study the manipulative forces of the frequently used lumbar spinal manipulations and the manipulative forces during cracking sounds of manipulations. (2)To study the body postures and angles during lumbar spinal manipulations, in order to provide a quantitative basis for the manipulations, and to provide a basis of biomechanics for analyzing lumbar spinal manipulations with finite element. (3)To Set up a three-dimensional and visible finite element system of lumbar spine, and study the displacement, distortion, vector and intra-stress distribution during the manipulations. And to provide a macroscopic basis for visible study of manipulations, study the mechanism of manipulations, exploring the method of optimizing the manipulations, and reducing the accidental injury of manipulations. (4)To study the trait of distortion, displacement and intra-stress distribution of intervertebral disc, vertebral body and posterior area of lumbar during the frequently used lumbar spinal manipulations, in order to analyze the mechanism, security and rationality of manipulations.Methods (1)The largest forces of thumb on the spinous process of the fourth cervical vertebra and the fourth lumbar vertebra were tested and recorded with a pressure sensor testing system during cracking sounds of the located and rotatory manipulation. (2) The manipulative forces on the left and right side shoulder were tested during the lumbar erected and rotatory manipulation. (3)The manipulative forces on shoulder and hip were tested during cracking sounds of the obligue-pulling manipulation, the lumbar rotatory-pulling manipulation, the lumbar located and obligue-pulling manipulation. (4)The manipulative forces on the lumbar spine were tested during the lumbar troflexed manipulation, the lumbar rotatory and troflexed manipulation and the lumbar-pushing and shoulder-pulling manipulation. (5)The X-ray films were get during manipulations, and were compared with the X-ray films before manipulations, the displacements of anteflected, troflexed, lateral curvature during manipulation were tested. (6)A young man's lumbar spine was scanned by CT with 1mm interval. Then, the jpg-format data of CT was inputted into computer. Sectional constructed a three-dimensional finite element system of lumbar L4.5 by the CT images. The finite element system contained of 24990 nodes and 15652 elements. (7)The frequently used lumbar spinal manipulations were decomposed by principium of manipulation. The parameters of mechanics were analyzed with the three- dimensional finite element system and computed with software Ansys 9.0. (8)The changes of distortion, displacement and intra-stress distribution in vertebral body, posterior area and intervertebral disc of lumbar spine were displayed during the manipulations. The results were compared with the relevant experimentation of biomechanical.Results (1)As the cracking sound, the forces to the fourth spinous process of lumbar vertebra were 5.07±1.30kg and 6.64±1.50kg respectively in left and right thumbs, the forces to the fourth spinous process of cervical vertebra were 4.73±1.04kg and 6.42±1.33kg respectively in left and right thumbs during the rotatory and localized manipulation. (2)The pushing force was 6.22±1.05kg and the pulling force was 7.47±1.02kg during the lumbar erected and rotatory manipulation. (3)As the cracking sound, the manipulative forces were 12.55±1.72kg and 12.75±1.65kg respectively to the left and right shoulder, and the manipulative forces were 13.59±1.63kg and 13.27±1.20kg respectively to the left and right hip during the lumbar obligue-pulling manipulation. The manipulative forces were 12.81±1.26kg and 12.41±1.39kg respectively to the tail's and the short's shoulder, and the manipulative forces were 13.73±1.00kg and 12.92±0.23kg respectively to the tail's and the short's hip. The manipulative forces were 13.27±1.23kg and 11.73±1.26kg respectively to the fat's and the thin's shoulder, and the manipulative forces were 13.73±1.00kg and 12.92±0.23kg respectively to the fat's and the thin's hip. (4)As the cracking sound, the manipulative forces were 10. 72±1. 65kg and 11.82±1.33kg respectively to the thoraces and hip during the lumbar located and obligue-pulling manipulation. (5)The pressures to the lumbar were 4.84±0.56kg and 6.34±0.93kg during the lumbar troflexed manipulation (two sides) respectively with 30°and 45 troflexed body postures. (6)The pressure of palm to lumbar was 8.49±1.31 kg and the pressure of genua to lumbar was 10.56±1.12kg during the lumbar troflexed manipulation (one side). (7)The pressure of palm to lumbar was in 3.5-9.7kg, and the average pressure was 5.90±1.58kg during the lumbar rotatory and troflexed manipulation. (8)The pressure of palm to lumbar was in 6.2-9.4kg, and the average pressure was 7.86±0.92kg during the lumbar-pushing and shoulder-pulling manipulation. (9) The displacement of inferior of L₅ vertebral body was 10.05mm during the lumbar troflexed manipulation (two sides). The displacement of inferior of L₅ vertebral body was 7.98mm during the lumbar troflexed manipulation (one side). The displacement toward anterior of the superior of L₄ vertebral body was 6.1mm and the displacement toward right of the superior of L₄ vertebral body was 5.35mm during lumbar located and rotatory manipulation. (10)The centers of intra-stress were distributed in facet joint, pedicle of vertebral arch and lamina of vertebral arch during the lumbar obligue-pulling manipulation. The intra-stress of posterior area was larger than that of intervertebral disc. There was a palinal vector from center of the intervertebral disc to the right, which distorted the intervertebral disc. (11)The centers of intra-stress were distributed in both side of facet joint, pedicle of vertebral arch and lamina of vertebral arch during the lumbar troflexed manipulation (two sides). The intervertebral disc protruded posterior. (12)The centers of intra-stress were distributed in left side of facet joint, pedicle of vertebral arch, vertebral body and lamina of vertebral arch during the lumbar troflexed manipulation (one side). The displacement vector of the left intervertebral disc was toward posterior and inferor. The displacement vector of the right intervertebral disc was toward anterior and superior. (13)The centers of intra-stress were distributed in left side of facet joint, pedicle of vertebral arch and lamina of vertebral arch during the lumbar-pushing and shoulder- pulling manipulation. The intervertebral disc distorted toward posterior. (14)These was not distortion and displacement in intervertebral disc toward posterior during the lumbar located and obligue-pulling manipulation. (15)These was a distortion of rotatory in intervertebral disc toward right during the lumbar rotatory and localized manipulation. The left intervertebral disc distorted toward anterior.Conclusion: (1)There wasn't directly relationship between the manipulative forces of thumbs and cracking sound during rotatory and localized manipulation, and had much effect of dominant and subdominant hand on the largest manipulative force(P<0.001). (2)There wasn't significance difference in manipulative forces to shoulder between the left and right during the lumbar obligue-pulling manipulation (P=0.655), just as the hip (P=0.410); but the force to hip was larger than the shoulder(P=0.016). There wasn't directly relationship between stature and the manipulative forces of the lumbar obligue-pulling manipulation (P=0. 226), but it was harder to manipulate the fat than the thin during manipulation (P=0. 002). (3)The lumbar obligue-pulling manipulation was safe to the intervertebral disc, but it was danger to lumbar vertebrae olisthy, isthmus fracture and facet joint damage, and it was more rational for manipulation in the healthy side. (4)The lumbar located and obligue-pulling manipulation was safe to the lumbar intervertebral disc protrusion and lumbar spinal stenosis. (5)The lumbar troflexed manipulation (two sides) was not suitable for lumbar intervertebral disc protrusion, lumbar vertebrae olisthy, isthmus fracture and facet joint damage. It was more rational for troflexing the healthy side leg in treat lumbar intervertebral disc protrusion during the lumbar troflexed manipulation (one side). (6)The lumbar-pushing and shoulder-pulling manipulation was not suitable for lumbar vertebrae olisthy, isthmus fracture, facet joint damage, lumbar intervertebral disc protrusion and spinal stenosis. (7)It was more rational for rotatory manipulation toward the healthy side during the lumbar rotatory and localized manipulation.