The Anatomy Study About The Correlation Of Pedicle Screws Resistance Pullout Strength In The Subaxial Cervical Spine

Objective:to discuss the correlation between pedicle screws resistance pullout and the ratio of screws diameter and pedicle spongy width,BMD and the screws diameter in the Subaxial Cervical Spine.and see if they affect the resistance pullout strength after their perforation.Methods:1,10 formalin-soak specimens, eliminate soft issue, keep cervical intervertebral disc neck, joint turkestan articular and five ligament.2, spiral CT measure each CT value of specimens and all pedicle medulla cavity diameter, quantitative QCT method for measuring with specimens of each bone mineral density,3, establish pedicle screws nail from C3-C7 segment by 2.0 mm drill press "solution unarmed buy nail method"; Three groups:bodies were randomized into 3.5 mm,4.0 mm and 4.5 mm of 100 pieces of screws, bolts: Homemade spies confirmed the walls a bottom, record pedicle respectively, and the external wall burst and normal wear out.4. Do spiral CT testing again in pedicle screw, record (normal, bursting or worn out).5. Do the biomechanical testing:all the screws specimens according to random sequence connected to 300kg-Spring uplink biomechanical testing, records of vertebral arch GenBa screw out since the Spring pulling force that screws resistance to scale the maximum. Results:SPSS statistical analysis pulling force y and R xl, BMD x2 screw diameter x3 and the situation of diameter in pedicle x4 (normal, bursting or worn out respectively set to level 0,1,2) do multiple linear regression analysis regression equation for:y=73.145+0.696 x1+0.798 x2+0.003 x3-0.085 x4; Regression equation analysis of variance F> 14.02, P<0.05.says pulling force y screw resistance in general than with screw clamps x1, BMD x2 vertebral x3 and screws, bolts, diameter pedicle situation in a linear regression relation. Pedicle screws pulling force and screw resistance ratio positively correlated than between vertebral, partial regression coefficient for 0.696, did after t test P< 0.005. standardization partial regression coefficient (0.564 SCB) for pulling force and bone density, resistance to the partial regression coefficient 0.798 t test, do after P<0.001, standardization partial regression coefficient (0.685 SCB). Resistance force and pull the diameter of the partial regression coefficient screw for 0.003, line t test> 0.05; after P Resistance force and pull the pedicle screw-in the partial regression coefficient for-after do t test entropy (P<0.05), and standardized partial regression coefficient (0.127 SCB).732.6 normal group tension value for 147.66 N, spiral cones+0.16 than for 126+139); 0.89-(Tension value is bursting group 380.26 N, screw 946+than 1.81+0.15 for cone (1.40-199); Worn out group for 574.38+134.27 tension value than for investigation of the cone, screw 2.05-2.600.34 (+),3 groups do t test (P<0.05), and after all that happened after pulling force burst resistant than normal group increases, and happen wear out than normal after pulling force of resistance decreases. Conclusion:cervical vertebral pedicle screws pulling force and screw resistance ratio positively correlated vertebral bone mineral density, and bone screw the correlation of the greater than with vertebral pedicle correlation, and the external wall wear out, but negatively related conditions, and the low correlation there was no correlation between screw diameter. Pedicle the external wall burst occurred after pulling force resistance than normal group increases, and happen wear out than normal after pulling force of resistance decreases.