Biomechanical And Clinical Study Of The Transoral Articular Mass Screw Of C2

Objective:1.To test the transoral articular mass screw of C2 with 6-hole TARP-IV for Atlantoaxial biomechanical stability;2.test the pullout strength of the transoral articular mass screw of C2;3.compare the preoperative and postoperative images、clinical effects and surgical diferences of patients undergoing the transoral articular mass screw of C2 with TARP-Ⅳ internal fixation or transoral transpedicular screw of C2 with TARP-Ⅳ.Method:1.Select 6 fresh frozen Craniocervical specimens to prepare control models and atlantoaxial instability models,and test atlantoaxial biomechanical stability with different nail placement methods and 6-hole TARP-Ⅳ on the instability models:(1)TARP+bilateral transoral articular mass screw of C2+bilateral patella group(T1)、(2)TARP+bilateral transoral transpedicular screw of C2+bilateral patella group(T2),use Motion Analysis Co.6 Eagle system to measure the range of motion(ROM)of atlantoaxial.2.Use the BOSE ElectroForce machine to measure the maximum pullout strength of the screws on the C2 specimens:the C2 vertebral body screw group(control group),the C2 transoral articular mass screw group,the C2 transoral transpedicular screw group.3.Collect 44 cases of TARP surgery,and divide them into four group according to the TARP plate median 2-hole pivot screw placement:including the bilateral transoral articular mass screw group(a)、the bilateral transoral transpedicular screw group(b)、the left transoral articular mass screw group(c)、the right transoral articular mass screw group(d);including the following measurement indicators:(1)preoperative and postoperative imaging ADI、CCA,、DCL、CMA(2)screw length、screw transverse angle and screw declination angle(3)Surgical bleeding volume、operation time、complications and ASIA classification.Result:1.The transoral articular mass screw of C2 with 6TARP-Ⅳ plate(T1)and the traditional anterior transoral transpedicular screw of C2 with 6-hole TARP-Ⅳ plate(T2)can significantly improve atlantoaxial biomechanical stability.there was no statistical difference between T1 group and T2 group in the atlantoaxial motion in 6 directions.2.The maximum pullout strengths of the C2 vertebral body screws group(a1)、the C2 transoral articular mass screw group(a2)and the C2 transpedicular screw group(a3)are:307.03±76.13N、414.86± 138.51N、490.36±116.93N;The comparison was statistically significant(P<0.05),and there was no statistical difference between a3 and a2(P=0.296).3.There were no significant differences in ADI、CCA、DCL and CMA among four groups of patients after surgery(P>0.05).The screw length、screw transverse angle and screw declination angle of the the C2 transoral articular mass screw and transpedicular screw are 20.48±2.35mm、26.43 ± 2.81mm、13.89±4.10°、15.48±3.42°、2.35 ± 8.19 °、9.28 ± 6.34°;A satisfactory fusion rate was obtained within 1 year after operation without loosening of nails or revision.Conclusion:1.Biomechanical stability and the maximum pullout strength:the transoral articular mass screw of C2 with TARP-Ⅳ can provide reliable biomechanical stability and pullout strengths as the transoral transpedicular screw of C2.2.Clinical studies have shown that the C2 transoral articular mass screw with TARP-Ⅳ in the treatment of atlantoaxial dislocation reduction、dentate process pulldown and spinal cord compression is similar to that of C2 transoral transpedicular screw,The screw length、screw transverse angle and screw declination angle of C2 transoral articular mass screw are:20.48±2.35mm、13.89±4.10°、2.35 ± 8.19°.