Surgery and environmental influence as risk-factors for the development of deep vein thrombosis in animal experiments.

The aim of this experimental study was to determine whether deep vein thrombosis (DVT) in animals occurs after osteosynthesis of the femur, and whether a postoperative drop in air pressure increases the frequency of DVT. Thus, osteosynthesis of the femur was performed in 10 New Zealand rabbits. Postoperatively a drop in air pressure of 300 hPA was induced. After 40 h in the pressure cabin ascending phlebography was performed (Group A). In a control-group of 10 other rabbits surgery was performed without postoperative drop in air pressure (Group B) while in a second control only the drop in air pressure was induced without surgery (Group C). The phlebographic studies showed DVT in 4 out of 10 rabbits in group A. In group B there was no demonstrable DVT while in group C one case of DVT was seen. The difference between group A and group B and C is statistically significant. In conclusion, a rapid drop in air pressure seems to have significant impact on the pathogenesis of DVT in rabbits after osteosynthesis of the femur.