Comparison of the pullout strength between anterior transpedicular screw,posterior pedicle screw and anterior vertebral body screw at upper thoracic spine
YANG Lijing
XIAO Zengming
LIANG Dongzhu
XIAO Shanwen
HE Juliang
Abstract：Objective To compare the pullout strength between anterior transpedicular screw, posterior pedicle screw,and anterior vertebral body screw at upper thoracic spine.Methods Six embalmed cadavers,containing the entire structure from C7to T5,were selected,and then were divided into three groups:the group of anterior transpedicular screw (ATPS group),the group of posterior transpedicular screw(PTPS group),and the group of anterior vertebral body screw (AVBS group).Randomization process was carried out on the specimens of each vertebra from T 1to T4before experiment. The both sides of pedicle of each vertebra was randomly assigned as two different numbers.According to the random re-sults,we inserted either ATPS or PTPS in the pedicle,and inserted a AVBS in the front of the same vertebral body.The screw axial pullout test was carried out on mechanics testing machine,and we recorded each screw length and peak pullout force,then made statistical analysis for the data.Results The length of screw path of the ATPS group increased from T 1to T4,and T1was shorter than T2to T4in the PTPS group, and T4was longer than T1to T3in the AVBS group(all P<0.05).The maximum pullout strength of T 3and T4were greater than that of T1and T2in both group of ATPS and PTPS (both P<0.05),but the maximum pullout strength of the AVBS group did not change significantly(P>0.05).Under the same condition for T1to T4,the length of screw path and the maximum pullout strength were greater in the ATPS group than in the PTPS,by the same token,PTPS was greater than AVBS(all P<0.05).The length of screw path was positive-ly correlated with its maximum pullout strength(r=0.997, P=0.000).Conclusion The length of screw path and the maximum pullout strength of ATPS were greater than those of PTPS and AVBS,which would help to improve the stability of the internal fixation system.
Keywords：pedicle screw fixationupper thoracic spineanterior pedicle screwposterior pedicle screwvertebral body screwpullout strength
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：4( 1-4 )