Thoracolumbar Vertebral Compression Fracture:through Injure Vertebrae Versus Across Injure Vertebrae 1 Year After Removing Implanting

Objective: Many studies reported on comparison between through injure vertebrae(6 pedicle screws)and across injure vertebrae(4 pedicle screws)in treatment for thoracolumbar vertebral compressive fracture.But few reported the clinical and radiographic outcomes for two surgical methods after removing implanting.This study is to compare the clinical and radiographic outcomes of through injured vertebrae(6 pedicle screws)and across injured vertebrae(4 pedicle screws)at time of 1 year after removing implanting.Method: A total of 41 patients with thoracolumbar compression fracture who were treated by through injure vertebrae(Group A)or across injure vertebrae(Group B)from January 2010 to June 2013 were included in this retrospective study.Then we observed anterior,middle and posterior vertebral height compression rate of injure vertebrae and Cobb angle at time of pre-implanting,1 week after post-implanting,pre-implanting-take-off(1 years after implanting pedicle screws)and 1 year after removing implanting in two groups.Theoretic height of anterior(middle and posterior)injure vertebrae is a.Actual is b.Actual inferior injure vertebrae is c.Actual superior injure vertebrae is d.Anterior(middle and posterior)injure vertebral body height compression rate is e.Middle vertebral height is the length that connection midpoint of segment that anterior and posterior endpoint of superior border of vertebral and midpoint of segment that anterior and posterior endpoint of inferior border of vertebrae.Cobb Angle for injure vertebral upper vertebral endplate in horizontal and injure vertebral lower vertebral endplate under horizontal angle;Cobb Angle before fixation implants is f;Cobb Angle 1weeks after implanting is g;Cobb Angle when taken out of internal fixation is h;Cobb Angle 1 year after internal fixation of take out is i;Cobb Anglecorrected rate is j;Cobb angle maintaining rate is k.Cobb angle maintaining rate after 1 internal fixation of take out is m.a=(b+c)/2;d=(a-e)/a;j=(f-g)/f;k=(h-g)/h;m=(i-h)/i.Meanwhile we compared the Oswestry Disability Index(ODI)score and Visual Analogue Scale(VAS)score of patient at time of pre-implanting,pre-implanting-take-off(1 years after implanting pedicle screws)and 1 year after removing implanting.Result: There is no significant difference in age,gender and fracture site in two groups.There is no significant difference in anterior vertebral compression rate at time of pre-implanting and 1 years after removing implanting,however,the anterior vertebral compression rate at time of 1 week post-implanting and pre-implanting-take-off in Group A were significantly better than those in Group B(P<0.001,P=0.043).There is no significant difference in middle vertebral compression rate at time of pre-implanting and1 years after removing implanting,however,the middle vertebral compression rate at time of 1 week post-implanting and pre-implanting-take-off in Group A were significantly better than those in Group B(P=0.046,P=0.042).There is no significant difference in posterior vertebral compression rate at time of pre-implanting,1 week post-implanting,pre-implanting-take-off and 1 year after removing implanting in two groups.There is no significant difference in maintenance of Cobb angle at time of pre-implanting,1 week post-implanting in two groups,however,maintenance of Cobb angle at time of pre-implantingtake-off and 1 years after removing implanting in Group A were significantly better than those in Group B(P=0.019,P<0.001).ODI score and VAS score decreased in two groups.But there were no significant difference in ODI score and VAS score at time of pre-implanting,pre-implanting-take-off and 1 year after removing implanting between two groups.Conclusion: Through injure vertebrae,in the aspect of the anterior,middle vertebral compression rate at time of 1 week post-implanting,preimplanting-take-off are significantly better than across injure vertebrae.But the efficacy of two surgical methods are not significant difference at time of 1year after removing implanting.Through injure vertebrae in holding Cobbangle was better than across injure vertebrae at time of pre-implanting-takeoff and 1 year after removing implanting.There were no significant difference in ODI score and VAS score between two groups.