Effects of bone wax on bacterial clearance

The hemostatic benefit of bone wax placed in cancellous bone occurs at the expense of the wax persisting at the bony site for years. As such, bone wax appears to act as a foreign body. This study examines the effect of bone wax on the ability of cancellous bone to clear bacteria. The iliac crest of rabbits was penetrated to a standard depth with an 18-gauge needle. Subsequently, nothing or Staphylococcus aureus, 10(5) colony-forming units, was innoculated in the needle site and followed by the subcortical placement of a cylinder of bone wax or similarly sized stainless steel rod. Ten days later, the site of bony penetration was excised and cultured. Eighty percent of animals whose bone was implanted with bacteria and bone wax together had positive cultures. Forty percent of animals whose bone was implanted with bacteria and a steel rod also had positive cultures. The difference between these groups (bacteria with bone wax or with steel rod) was not statistically significant. However, these combinations of bacteria with foreign body were significantly different from the bacteria only or bone wax only or steel rod only groups in which no positive cultures were observed. The data indicate that bone wax significantly impairs the ability of cancellous bone of rabbits to clear a standard inoculum of S. aureus. This effect appears to be the same as that observed with a different but similarly sized foreign body (steel rod).