The Image Measure Of The Insertion Angle For Lumbar Cortical Bone Trajectory Screw Using Computed Tomography And Its Clinical Significance

Objective:We measured the different angles of the CBT screw by CT datum,including the angle between the trajectory of the screw and the lamina of the lumber,and the angel between the trajectory of the screw and the sagittal plane.We hope the measurement of the angles can supply guidance for the placement of the CBT screws.Method:We collected 100 patients' CT datum of the lumber,which were completed from June 2016 to December 2016 in the First Affiliated Hospital of Soochow University.The cases include 50 male patients and 50 female patients.The PACS system was used for the measurement.The angle between the trajectory of the screw and the lamina is defined as cephalad angle.The angel between the trajectory of the screw and the sagittal plane is defined as transverse angle.We analyzed the angle results among the following:both sides of the vertebrae,the male and the female patients and the different vertebrae.Results:There was no significant difference in the cephalad and transverse angles between both sides of the lumber vertebrae.There was no significant difference in the cephalad and transverse angles between the men's and women's vertebrae.The cephalad angles of L1-5:(51.29±3.88)°;(50.68±3.37)°;(49.69±2.27)°;(49.09±2.49)°;(48.24±2.49)°.The cephalad angles decrease gradually from L1 to L5.There were statistical differences in the cephalad angles.The transverse angles of L1-5:(8.84±1.50)°;(8.92±1.56)°;(9.08±1.37)°;(9.11±1.40)°;(9.06±1.28)°.There was no significant difference in the transverse angles.Conclusion:There were statistical differences in the cephalad angles from L1-5.The cephalad and transverse angles will provide guidance to the surgeons to use the CBT screws.