The Arc-Track Private Lock Pedicle Orthpedics Fixation System â…¡ Design Research And Clinical Application

Objective:Development of the Chinese people for spinal pedicle screw-rod fixation system of orthopedic devices, and associated biomechanical testing and clinical application of research, evaluation of its effectiveness.Methods:This study is divided into three parts:1 the arc-track private lock pedicle orthopedics fixation systemⅡdesign and development:Spine at home and abroad of the characteristics of each instrument, absorbing the merits of various equipment to improve the deficiencies. Anatomical data by Chinese people in the design and manufacture the arc-track private lock pedicle orthopedics fixation systemⅡ.2 bio-mechanics test:Design based on the actual application of the test methods and procedures, System fixed to the axial loading experiments, the overall bending equipment to reverse the experiment, a fixed rod holder from the flexible pull-out strength in the experiments, pull-out strength of pedicle screws from the comparison test, a fixed vertical rod bend and the finite element analysis, screw bending test and the overall fatigue experiments. According to test data of the pilot model of integrated mechanical analysis.3 clinical application:Since October 2005-2008 in January in the clinical application of ALPFⅡof the treatment of spinal disorders89 cases, follow-up to be a complete and up to 12 months 89 cases.Result:First, the biomechanical test results:1 An axial load test:Afterburning points in the axial load, the load and strain relationship is linear. When the load reached at 600N, the strain point is still the linear strain changes, indicating that the overall structure of the model is still in steady state, showing that the high flexibility.2 Reverse bending experiment:Specimen bending torque and the relative twist angle between the two ends of a linear relationship. Bending torque reached 300 N·cm, the twist angle<6°, the overall structure of the sample without any signs of damage on the structure of the sample have a good ability to bending-twisting.3 Fixed rod holder from the flexible pull-out strength in the experiment:Experiments showed that the minimum fixed bar pull-out strength, that is, a fixed rod holder in the flexibility of both the sliding load at the time of> 3300N; the greatest pull-out strength, that is, sliding friction are the most> 8500N. Experimental data shows that the use of flexible fixed screw-rod holder with high reliability. In addition, the loosening of the fixed rod to completely pull out there> 5000N mechanical gradient, showing that the holder a high degree of flexibility in the safety and high flexibility. Since the pedicle screw pull-out test:ALPFⅡbiggest screw pull-out strength, compared with CCD Screw difference was significant (P<0.001) 4 Finite element analysis of test: Physiological spinal curvature in accordance with fixed pre-bending rod in the column force is more uniform stress distribution and deformation caused by the smaller, closer to the biological fixation.5 screw bending experiment:the data from the testing, we can see that the inside of the lateral bending moment greater than about 2 times. When the external load is 40Kg, the maximum lateral bending moment M= 867.5N-cm, medial to turn away from the M=-273.4N-cm. Lateral stress is greater than about 2 times the inner stress, maximum stress insideσ=-145.6Mpa, lateral maximum stressσ=487.0Mpa, the above-mentioned law of model structure and characteristics of test match, and a better viscosity materials elastic characteristics.6 the overall fatigue test:data from the test, in the fatigue test, when the model of circulation for more than 10 million times, no model is any damage, model no loosening of the connection site. Second,Clinical application of the results:89 cases were in this group of patients received a complete follow-up, followed up for 12 to 23 months, an average of 14 months, after you can, get things built before the leading edge of the last follow-up of the vertebral height, vertebral wedge angle-dependent, the latter preoperative Cobb angle compared with the P values are "0.001, before and after the margin of thoracic and lumbar load power line and curve are a good recovery. Patients were followed up more than 9 months, had received bone healing. No broken nails and kyphosis occur, without a high degree of loss. Recent follow-up of low back pain, according to Denis classification by low back pain assessment:in this group P1 49 Li (55.1%); P2 28 Li (31.5%); P3 7 Li (7.9%); P4 5 Li (5.6%); P5 0 cases (0%).45 cases (50.6%) to restore the original work or heavy manual labor; 35 cases (39.3%) to replace manual work or engage in light; 9 cases (10.1%) live independently, but not to participate in work or labor.Conclusions:1 Through biomechanical testing has ALPFⅡwith good stability, structure, process of its under load, stress and bending moment nails were linear law. Screw of the lateral stress and bending moment is greater than the inside on the inside of the smaller stress, can withstand greater stress and bending moment, in the variable load a certain fixed characteristics of visco-elastic. Met the requirements of the biological fixation. Reverse the overall test of no significant loosening in the overall high-intensity fatigue test more than 105 non-stamping destruction and loosening of the fixator reasonable structure, the overall stability of a good, fully met the requirements of spine biomechanics.2 Clinical results showed that the healing of spinal injury, intervertebral height, spinal sequence, the recovery of neural effects are good, the fixation system is simple, easy to grasp, a good reduction, fixed and reliable with few complications.