Measurement Of Projection Angles Of The Iliac Tubercle-acetabular Axis View And The Sciatic Buttress Axis View

Objective: The specific projection angles of the iliac tubercle-acetabular axis view and the sciatic buttress axis view were determined by the measurement of adults CT reconstruction.The clinical significance of the two axis views was discussed briefly.Methods: 34 healthy adults were recruited for pelvic CT scan.And the CT image data were transmitted to the Mimics image analysis software for three-dimensional pelvic reconstruction.The three dimensional projection angles of the iliac tubercle-acetabular axis view and the sciatic buttress axis view were measured on the reconstructed image.At the same time,the safe diameters of the screw inserted along the new projection angles(the maximum diameter of the screw without penetrating the bone cortex).Results: The angle between the iliac tubercle-acetabular axis view and the coronal plane is 33.38-57.42°(mean 47.51°),the angle between the iliac tubercle-acetabular axis view and the horizontal plane is 3.12-31.31°(mean 15.05°)and the sagittal plane is 24.41-46.42°(mean 38.06°).The safe diameter of the screw inserted through this angle is 3.5-6.2 mm(mean 4.96 mm).The angle between the sciatic buttress axis view and the coronal plane is 10.24-36.29°(mean 23.12°),the angle between the sciatic buttress axis view and the horizontal plane is 37.47-58.41°(mean 49.51°),and the sagittal plane is 23.65-38.75°(mean 30.68°).The safety diameter of the screw inserted through this angle is 7.0-12.2 mm(mean 9.98 mm).Conclusions: The measurement results of the iliac tubercle-acetabular axis view and the sciatic buttress axis view have certain guiding significance for the placement of the Schanz screw in the pelvic anterior ring external fixator and the anterior inferior iliac spine screw in INFIX.