Thoracolumbar Vertebral Body Using Funnel Technique And Freehand Technique In Pedicle Of Vertebral Arch Screw Biomechanics Study

Objective:To compare the funnel technique (funnel technique) and unarmed techniques (free-hand technique) biomechanical properties of thoracolumbar vertebral pedicle screw placement using the funnel technique feasibility.To provide theoretical basis for clinical application.Methods:Collect8fresh thoracolumbar specimens (T11-L3), eliminating the muscle, retaining the anterior and posterior longitudinal ligaments、ligamenta flava,、interspinous ligament and the corresponding vertebral body on the facet joint capsule, using polymethylmethacrylate bone cement to upper and lower T11-L3entrapped, made into a full thoracolumbar experimental specimens, the8specimens were divided into two groups, group A as a freehand technique of pedicle screw fixation; group B funnel technique placement of pedicle screw fixation, two groups of rows of thoracolumbar vertebral stability, screw pullout resistance and maximum pull-out power as well as the axial stiffness of the comparison, analysis and comparison of thoracolumbar vertebral funnel technique with the free-hand technique two placement of pedicle screws in the biomechanical properties.Results:1, Thoracolumbar vertebral load strain relation:A freehand technique nailing group than the B funnel technique nailing group average strain is less than about12%, statistics showssignificant difference (t=2.625, P<0.05). A group better than B group;2, Thoracolumbar vertebral load-displacement relationship:A freehand technique nailing group than the B funnel technique nailing group average displacements as small as17%, statistics showssignificant difference (t=2.878, P<0.05), A group better than B group again;3The thoracic and lumbar strength:A freehand technique nailing group than the B funnel technique nailing group average strength higher12%, statistics showssignificant difference (t=2.733, P<0.05), the effection of the pedicle screw fixation Ais better than B;4, Thoracic and lumbar spine axial rigidity:A freehand technique nailing group than the B funnel technique nailing group average axial stiffness higher17%, there is a significant difference of statistics (t=2.968, P<0.05), A group of axial deformation capacity is stronger than the B group;5, Thoracic and lumbar torsional mechanical properties:A freehand technique nailing group than the B funnel technique nailing group average torque higher11%, torsional stiffness higher14%, statistics showssignificant difference (t=2.836, P<0.05), A group more stable;6, Pedicle screw pullout test:A freehand technique nailing group than the B funnel technique nailing group average pull-out force higher18%, statistics showssignificant difference (t=2.974, P<0.05), pull-out of the loss of energy in group A more13%than in group B, statistics also shows significant difference (t=2.614, P<0.05). Pull-out power consumption using the freehand technique t is larger than funnel technique.Conclusion:Thoracolumbar vertebral pedicle screw placement using A freehand technique than the B funnel technique in pedicle screw bending, torsional strength and axial stiffness are strong, and the screw pull-out spending power is greater, it can be concluded that:funnel technique has the advantages of simple operation, although practical, accurate, convenient, but screw strength are inferior to the free-hand technique. The patients using funnel technique in clinical operation require postoperative long time of bed rest to reduce the intensity of activity so that avoid loosening of screws, fracture, pull out the consequences.