Sacroiliac screw fixation is the only minimally invasive technique for stabilizing unstable posterior pelvic ring fractures. X-ray/CT methods identify sacral shape variants, which influence screw fixation feasibility at sacral segment S1. As no reliability analysis was previously published, this study analyzed four X-ray/CT-based screw corridor evaluation methods. CT datasets of 80 human pelvises (♂[Formula: see text][Formula: see text], ♀[Formula: see text][Formula: see text], [Formula: see text] years, [Formula: see text][Formula: see text]cm, [Formula: see text][Formula: see text]kg) were used. CTs were post-processed using Amira 5.2 software to generate 3D models and analyzed for S1 transverse 7.3[Formula: see text]mm screw corridors using a C++ program. CT-slices and radiograph-like images were generated per each classification’s requirements. Five surgeons independently assessed sacral shape and transverse screw insertion feasibility. Sensitivity, specificity, and positive/negative predictive values were calculated. C++ analysis indicated feasible screw insertion in 66 cases (82%). Sensitivities were 86% (Mendel), 75% (Routt), 74% (Carlson), and 67% (Kim). Specificities were 73% (Mendel) and 79% (Kim). Mean positive predictive value spanned from 54.6% (Mendel) to 26.2% (Carlson); negative predictive value spanned from 94.5% (Kim) to 90.4% (Carlson). No significant differences existed between surgeons. Mendel’s classification provides reliable and reproducible assessment via the lateral sacral triangle, without additional CTs like Carlson or Routt or the subjectivity of Kim’s method.
Percutaneous Robot‐Assisted
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Iliosacral Screw Fixation in Unstable Posterior Pelvic Ring Fracture
