Pelvic antropometric measurement in 3D CT for placement of two unilateral iliosacral S1 - 7.3 mm screws

Abstract

Purpose Stability of the dorsal pelvic ring is important for patient mobilisation and can be restored using several surgical procedures after fracture. Placement of percutaneous iliosacral screws is a reliable and minimal-invasive technique to achieve stabilisation of the dorsal pelvic ring by placement of two screws in the first sacral vertebra. Aim of this study was to evaluate 3D CT scans regarding the anatomical possibility to place two 7.3 mm iliosacral screws for fixation of the dorsal pelvic ring. Methods 3D CT datasets of 500 consecutive trauma patients with 1000 hemipelves of a mid-european level I trauma centre with or without pelvic injury were evaluated and measured bilaterally in this retrospective study. Results One thousand hemipelvic datasets of 500 patients (157 females, 343 males) with a mean age of 49.7 years (18 to 95) were included in this study. Only 16 hemipelves (1.6%, 11 in females, 5 in males) in 14 patients (2.8%, 9 females = 5.73%, 5 males = 1.5%) showed too narrow corridors so that 7.3 mm screw placement would not be possible (p = 0.001). In women, too narrow corridors occurred 3.9 times as often as in men. Only two females showed this bilaterally. Conclusion The evaluation of 3D CT scans of the pelvis showed the importance of planning iliosacral screw placement, especially if two 7.3 mm screws are intended to be placed in the first sacral vertebra.

Percutaneous two unilateral iliosacral S1 screw fixation for pelvic ring injuries: a retrospective review of 38 patients

“…Suda et al [5] recently evaluated the safety of two unilateral IS S1 screws in a 3-dimensional dataset of 1,000 hemi-pelvises of 500 patients with trauma. They concluded that 99% of male and 96% of female hemi-pelvises had adequate room to place two 7.3-mm screws at a 5-mm distance into the S1 vertebra.…”

“…Thus, it has several advantages, particularly in patients with unstable hemodynamic conditions. However, the use of one IS screw is inferior with respect to rotational stability and load cycles [4,5]. Therefore, the fixation of two unilateral IS S1 screws or the addition of an IS S2 screw is recommended in completely unstable pelvic ring injuries [4].…”

Bony Sacral Volume after Sacro-Iliac Screw Fixation of Pelvic Fractures Is Dependent on Reduction of the Anterior Pelvic Ring

“…Although the number of high-energy pelvic fractures is decreasing, demographic changes lead to a dramatic increase in pelvic fractures of the elderly [ 6 ]. The sacral anatomy is relatively complex and shows quite some variability [ 7 ]. Therefore, evaluation of the sacral morphology with two-dimensional methods is difficult.…”