Cadaveric biomechanical study using CT imaging and 2D/3D computer modeling to quantify how progressive cranial displacement of zone II sacral fractures reduces the cross-sectional area and intraosseous volume available for safe iliosacral screw placement — testing whether there is a threshold displacement beyond which fixation becomes geometrically unsafe.
When planning iliosacral screw fixation for a zone II sacral fracture, do not accept residual cranial displacement ≥10 mm — the geometry of safe screw passage degrades sharply beyond 1 cm, and at 15–20 mm, single-screw fixation may be impossible in most patients.
If fluoroscopic reduction looks 'close enough,' remember that intraoperative fluoroscopy is known to underestimate true sacral displacement, so pursue anatomic reduction even if it requires open reduction.
Cadaveric biomechanical study using CT imaging and 2D/3D computer modeling to quantify how progressive cranial displacement of zone II sacral fractures reduces the cross-sectional area and intraosseous volume available for safe iliosacral screw placement — testing whether there is a threshold displacement beyond which fixation becomes geometrically unsafe.
When planning iliosacral screw fixation for a zone II sacral fracture, do not accept residual cranial displacement ≥10 mm — the geometry of safe screw passage degrades sharply beyond 1 cm, and at 15–20 mm, single-screw fixation may be impossible in most patients.
If fluoroscopic reduction looks 'close enough,' remember that intraoperative fluoroscopy is known to underestimate true sacral displacement, so pursue anatomic reduction even if it requires open reduction.