C-arm contamination of the surgical field: Can contamination be reduced with an intervening drape?

Contamination of the surgical field by the C-arm in orthopaedic procedures is a significant potential source for surgical site infections. The purpose of this study was to explore the utility of a split sheet to aid in prevention of secondary contamination from the C-arm on the C-arm side of the operative field.

A C-arm and a surgical table were draped by standard techniques. The surgical table was split in thirds: the surgeon's side, the C-arm side of the operative field, and the middle for contamination analysis. Fluorescent powder was used to simulate a contaminant and placed on the C-arm, floor and lower portions of drapes. The C-arm was cycled between PA and Lateral positions. Powder transfer to the field was visualized with a camera under uniform UV light. Photographs were taken to measure fluorescent pixels prior to cycling the C-arm and at 5, 10 and 15 cycles. This protocol was repeated using a split sheet (U-drape) to isolate the C-arm below the operative field. Image J was utilized to calculate differences in the number of pixels brighter than the control image.

Using standard draping techniques, there was contamination of the surgical field with the C-arm side of the operative field having the highest level of fluorescent pixels. The number of fluorescent pixels was linearly correlated with the number of PA to Lateral cycles. At the end of 15 cycles, the average number of fluorescent pixels for the intervening draping technique was 2.9 pixels compared to the standard draping technique of 3939 pixels (p = 0.0078).

The addition of a U-drape between the C-arm and the table results in a statistically significant reduction in surgical field contamination as a result of secondary transfer from the C-arm.

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