The Number Of Pedicle Screws In Lumbar Non-fusion Biomechanical Test

Objective Design stress under flexion and extension capacity of threaded titanium bar,titanium rod supporting pedicle screw. Nail bars and nail tail connection is locked at90degrees. Spine flexion and extension load either micro-dynamic fixation effect, withoutaffecting the fixed stabilityMethods There are6human spine specimens（L1-L5）. Experiments were performed tocontrol their own. Traditional titanium rod as the control group, self-designed titanium rods asthe experimental group. Control group number is0. In experimental group:2spiral, cuttingdepth of0.5mm, numbered2-1.2spiral, cutting depth of1.0mm, numbered2-2.3spiral,cutting depth of0.5mm, numbered3-1.3spiral, cutting depth of1.0mm, numbered3-2.4spiral, cutting depth of0.5mm, numbered4-1.4spiral, cutting depth of1.0mm, numbered4-2.5spiral, cutting depth of0.5mm, numbered5-1.5spiral, cutting depth of1.0mm, numbered5-2.The traditional screw and rod system implant in pedicle. Measurement of axialcompression, flexion, extension, lateral bending, torsion and other fixed segments in differentdirections, and load and adjacent segment disc stress of size. The design of the pedicle screwsystem implanted pedicle in the direction of the stress test. After completion of the stabilitytest, the titanium rod once100,000fatigue experiments. The measured results based on pairedt-test for statistical analysis.Results In axial compression, flexion, extension, lateral bending experiments. Theexperimental group and control group compared to the adjacent segments of the fixed disk ofthe stress reduced the stress to increase the fixed segment. The statistical analysis,2-1,2-2 compared with the traditional fixed, P>0.05, no significant differences.3-1,3-2,4-1,4-2,5-1,5-2compared with the traditional screw and rod system, P <0.05,significant difference.2-1,2-2are no difference with the traditional fixed equipment. Youcannot micro-adjustment effect. In reverse the experiment, Experimental group compared withthe control group. Adjacent segments of the fixed disk the stress decreases, the fixed segmentof the stress increase, P<0.05, all types of screw and rod system can play a regulatory role.After the fatigue test, ROM value indicates that the different loading direction is fixed stage.The2-1,2-2,3-1screw and rod system and compared to traditional screw-rod system, P>0.05,after the fatigue test, There is no significant difference in the stability of the three types ofscrew and rod system with the traditional screw and rod system.3-2screw-rod system, P<0.05, indicating the stability of the screw and rod system of the model with the traditionalscrew and rod system has significant differences. The value of ROM is greater the unstable isinstability.Conclusion With the increased number of threads and the cutting depth in the platebetween adjacent segments of the stress gradually decreases. The fixed system can play amicro adjustment of the fixed effect. By statistical analysis,2-1,2-2, and compared to thetraditional screws and rods, no significant difference. In fatigue experiments, the type of3-2,4-1,4-2,5-1,5-2models titanium rod fracture. Affected by the fatigue factor, The2-1,2-2,3-1stability with the traditional screw and rod system, no significant difference.Pedicle screw system can play a stabilizing effect. By biomechanical testing and statisticalanalysis, Thread, cutting depth of0.5mm titanium rod is optimal titanium rod. Play amicro-adjustment effect, but also to maintain the stability of a fixed stage.