Dorsal oblique pelvic external fixator

In haemodynamically unstable patients with an unstable pelvic ring injury t he primary stabilisation of the pelvis and thus reduction of pelvic volume is important for the success of the treatment. The pelvic C-clamp is an app roved emergency device for these unstable pelvic ring injuries. A secondary procedure though is necessary in most of the cases with a hig rate of woun d problems in already traumatized soft tissue areas. The ventrally placed e xternal fixator is a simple and quick procedure with little soft tissue dam age. Though primary stability is sufficient even for C-type injuries, biome chanic stability of the posterior pelvic ring is often isufficient for mobi lization. Based on biomechanic considerations, a new dorsal oblique pelvic external fixator was developed for pelvic C-type injuries. With the advanta ges of the supraacetabular fixator and two additional Schanz screws the ven tral fixator should stabilize the posterior pelvic ring with comparable sta bility to the pelvic C-clamp. A primary and already definitive minimal inva sive stabilization of the posterior pelvic ring was the aim. In the first s eries several variations of this asymmetric fixator with two different Scha nz screw applications were tested biomechanically. In a second series the f avorite version was tested versus the supraacetabular fixator and the pelvi c C-clamp. Both of the biomechanic test series were performed with artifici al pelves in the one leg stance model in the material testing machine. SI d isruption and sacral fracture were the posterior instability types in 6 pel ves each. There was no statistically significant difference between the dor sal oblique fixator and the pelvic C-clamp. But the new fixator was signifi cantly more stable than the supraacetabular fixator or the new fixator with out pretension.