Experimental Study Of The Subaxial Cervical Screws Placement By Using The Pedicle Aiming Device

Objective:The purpose of this study was to investigate the accuracy and the security of subaxial cervical screws placement under axis pedicle view using the pedicle aiming device. Methods:After six human subaxial cervical(C3-C7) dry bones CT scanning, we measure outer pedicle width(OPW), outer pedicle height(OPH), Inner pedicle width(IPW), Inner pedicle height(IPH), Pedicle transverse angle a(PTA), Pedicle sagittal angleβ(PSA). To compare the parameters between the left and right pedicles of each vertebrate using paired t-test and the parameters between male and female pedicles of the same segment using independent sample t test. Significance of correlation was established in terms of the P value for comparison of the various parameters with a significance level of P<0.05. Then we utilize self-design pedicle aiming device under axis pedicle view to place pedicle screws, and evaluate the result of pedicle screws. Result:There were no statistically significant difference was observed between right and left sides except PTA in females at C3and PSA in males at C3(P<0.05). OPW, OPH, IPW and IPH showed increase from C3to C7both in males and females, and OPW smaller than OPH, IPW smaller than IPW. PTA in two groups showed increased from C3to C4, then decreased from C4to C7, the C4is maximum. In two specimens, PSA decreased from C3to C7, and both from C6the angle of PSA begin to toward the coccyx. The excellent rate of the screws was90.0%on the criterion of Neo. Using the screws length30mm were completely placed into the pedicles, the rate of vertebral body wall perforation is38.3%. Conclusion:Using the self-design pedicle aiming device under the fluoroscopy-assisted pedicle axis view technique can improve the accuracy and the security of subaxial cervical screws placement.