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Background and purpose: spine internal fixation is effective internal fixation for spinal tumors, tuberculosis, vertebral fractures and disc disease and other spinal disorders, before various spinal fixation devices of the road, by the French SCIENT'X The company design and manufacture of the lumbosacral anterior security steel plate (PACH) is one of the more fixation devices in recent years in the field of spinal surgery applications, suitable for lumbar anterior fusion front or side of the front fixed, has the following characteristics: 1, its shape conforms to the front side of the horizontal curvature of the vertebral bodies, to help improve the stability of the horizontal and sagittal plane; bilateral fixed to provide a stereoscopic three-dimensional stability; 3, with a screw safety system: welding on the steel plate the elastic titanium strip can be bent so that the screw through the recovery exit to avoid screw; surface nicks attached to the vertebral body can make it perfect. But we gradually discovered in the clinical application of the plate, there are some shortcomings: lack of the steel plate as a monomer with two holes steel plate, surgery generally required to implant two steel process complex, if only implanted a steel plate fixed firmly may ; 2, the steel plate is designed in accordance with the the foreign ethnic spine anatomical characteristics, can not be fully consistent with the anatomical characteristics of the people spine; 3, spacing and angle of the surgery two steel plates placed no clear standard biomechanical stability can not be guaranteed. The purpose of this study is that people lumbosacral vertebral anatomical structure statistical analysis, on the basis of the fixed plate in the existing PACH, the improvement overall composite Sikong steel sheet, and it radians, length and angle can be completely adapted for people anatomical structures of the lumbosacral spine specimens on biomechanical testing, the biomechanical indicators to achieve the desired results. Methods: 1, approximately 350 cases of normal adult lumbosacral lateral X-ray lumbosacral angle, lumbar 5 sacral 1 vertebrae and intervertebral disc height measurement and statistical analysis obtained the normal people lumbosacral structure value range. 2, in lumbosacral vertebrae structural measurements on people on the basis, combined with the front side of the lumbar 5 sacral 1 spinal vascular distribution characteristics, improved lumbosacral anterior steel plate height, width, angle, curvature of the design parameters to make it consistent with people lumbosacral anatomical characteristics. 3, the production of steel sample, and biomechanics of the human spine specimens testing relatively improved plate group, the PACH plate group, control group biomechanics. Results: 1 through 350 normal adult standing a bit lumbosacral anteroposterior and lateral X-ray of lumbosacral angle, waist 5 and sacral 1 vertebral disc height measurements obtained the values ??of normal people lumbosacral structure statistical results: L5 vertebral body height (27.1 ± 2.3) mm, S1 vertebral height (22.3 ± 2.8) mm, the L5 S1 intervertebral disc height (8.2 ± 0.3) mm, lumbosacral angle (129 ° ± 5.9 °) . 2, based on the findings of the anatomical structure of people lumbosacral parts, we have developed improved lumbosacral anterior plate fixation system design parameters, steel plate, height: 28,32 mm 2, plate width: 20 mm steel plate angle: 125 °, 130 °, 135 ° 3 species, steel radians: arc length 22 mm, the chord length of 20 mm, the screw length: 30,32.5,35,37.5,40,42.5,45 mm, screw diameter: 5 mm. Spherical head, threaded self-tapping screw, screw natural state tend to head to tail on both sides, and the angle between the head and tail side 18 °. 3, the test specimen before bending test, continuous load to set the radial degrees, record load - displacement curve, select 500N load determination of the control group and the experimental group in the post-extension, lateral bending under the conditions of displacement comparison, the results show that the improved flexural capacity of the plate group is better than the the PACH group (P lt; 0.05). Compression experiments, according to the load - displacement curve, calculated in 400N stiffness under load groups, the PACH group for 87.4N/mm improved plate group 105.8N/mm, a difference of 21%, a statistically significant difference (P lt; 0.05). Finally reverse the experiment, when 5 ° corner, the improved plate group and PACH group spine specimens required torque than the control group increased by 54.6% and 53.7%, respectively, and both torsional rigidity similar, there was no statistical difference (P> 0.05). Conclusions: In this study, people lumbosacral site including the lumbosacral angle L5 and S1 vertebral body height L5S1 in disc height measurement statistics anatomical structures, draw people lumbosacral the vertebral anatomical structure specific range of values, and analyze the waist indicators of improved lumbosacral anterior plate design parameters the sacral anterior side of the vascular structure of the distribution characteristics. 2, in accordance with the design parameters of the production of steel plate samples, installed after the human spine specimens fully compliant with the people lumbosacral anatomic characteristics, and is located in the lumbosacral front side surgery \. Improved lumbosacral anterior plate system biomechanical testing in flexion, extension, lateral flexion, rotation the biomechanical stability are better than or close to existing PACH steel plate four physiological state of motion, flexible and easy to operate, and perfectly suited to the Chinese the lumbosacral vertebrae site ALIF internal fixation needs.
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