Comparison of the operation safety and biomechanical stability of sacral alar-iliac vs. sacroiliac screws in the fixation of sacroiliac joint in simulated models of low bone density.

Background: Sacral alar-iliac screws (SAISs) have been used for sacroiliac joint and are superiority to traditional sacroiliac screws (SISs) in patients with low bone density. The aim of this study was to investigate the operation safety and biomechanical stability of the SIS, transsacral-transiliac screw (TSTIS), S1AIS and S2AIS in the treatment of sacroiliac joint in simulated models of low bone density.

Methods: CT data from 80 normal pelvic structures were employed to measure the anatomical parameters, including the safety zones of the S1AIS and S2AIS at the insertion point and the trajectory lengths of the SIS, TSTIS, S1AIS and S2AIS.