BIOMECHANICAL COMPARISON OF DIFFERENT DEV ICES FOR EMERGENCY STABILIZATION OF THE PELVIS

Massive bleeding with shock is still the most frequent reason for earl y death after complex pelvic trauma. For hemostasis, fracture stabiliz ation in the pelvic ring is an important aspect. By use of the externa l fixator and introduction of emergency pelvic c-clamps, attempts were made to include pelvic ring stabilization on the early resuscitation algorithm. This biomechanical study compared a simple anterior externa l fixator (one supraacetabular pin on each side), the emergency pelvic c-clamp (Ganz) and the Browner modification of the clamp (''ACE clamp ''). Two fresh-frozen human cadaver pelves were loaded in a one-leg st ance model. The displacement and rotations on the site with the fractu re were measured with a 3D measurement system. Fracture models include d a Tile type B injury and two Tile type C instabilities (pure SI disl ocation; transforminal sacrum fracture). In type B injuries all method s withstood loading with 100% of the body weight (640/700 N). In C-typ e injuries with SI dislocation the external fixator showed no signific ant holding force, whereas the two c-clamps withstood loading of 112 N and 160 N. In the transforaminal fracture model no one method withsto od a load of more than 40 N. The combination of the clamps with the ex ternal fixator increased the holding strength to 66 N and 103 N. Altho ugh a single-leg-stance model does not reflect the emergency situation , in which the patient is normally in a supine position, the data reco rded are comparable to those observed in earlier investigations. They suggest an acceptable stability of the c-clamps for pure SI dislocatio ns, whereas in unstable pelvic fractures, including transforaminal fra cture lines, stabilization should be enhanced by an anterior device as soon as possible.