The Screw’s Parameters In Pedicle Screw Internal Fixation Device For Anterior Pelvic Fractures: A Digital Study

Objective:To study the size,length,and direction of the screw,for guiding the operation of percutaneous pedicle srew internal fixation device for anterior pelvic fractures.Method:Collect normal pelvic computed tomography scans of the adult from March 2014 to June 2015 were obtained in the first Chenzhou people’s hospital,45 males and 45 females.Import CT images into Mimics 10.0 to reconstruction. Measure the tilt angle between body and coronal plane,sagittal plane in the 2 dimensional image. Simulate the screw insertion and measure the screw’ length in the bone and diameter, read the parameter of screw’s direction in the 3 dimensional image.To calulate the angle between screw and human coronal and sagittal plane. Import the parameters measured into SPSS 18.0,contrast analysia of male and female and contrast analysia of left and right.Result:The screw’s length in ilium was 130.64~156.42mm(144.25±5.56mm) in man and 124.11~153.70mm(140.57±5.97mm) in female.The diameter was 10~16mm(13.26±1.35mm) and 10~14mm(12.16±1.00mm) in male and female respectively.The angle between screw and human coronal was 42.46°~61.63°(51.07°±4.32°)in man and 38.91°~56.30°(48.88°±4.40°) in female. The angle between screw and human sagittal was 15.58°~30.62°(24.71°±2.54°)in man and 19.39°~32.03°(23.64°±2.20°) in female.(1)Left and Right: The angle between screw and human coronal in man and female dealed with contrast analysis of left and right respectively,with no statistical difference(P>0.05),the sagittal plane result as well(P>0.05).(2) Man and Female: The angle between screw and human coronal in feft and right dealed with contrast analysis of man and female respectively,male had larger angle, and the difference were of statistical significance(P<0.05) and the sagittal as well(P>0.05).(3) Length in the Bone: Compare with the lift, the length of right screw in man had no statistical difference(P>0.05),the same as female(P>0.05). Compare with the female,male had a longer length, the difference were of statistical significance(P<0.05).(4) Diameter:The diameter of screw in man dealed with contrast analysis of left and right respectively,there was no statistical difference(P>0.05),the same as female(P>0.05). Compare with the female,male had a larger diameter, the difference were of statistical significance(P<0.05).Conclusion:Through the digital three-dimensional reconstruction measurement,insert screw in bony channel that between anterior superior iliac spine and acetabulum roof to the posterior superior iliac spine is feasible. When master the screw’s diameter,length and direction in operation is safe.It is worth extending in clinic and academic.