3.1 Contamination in different grade operating rooms and under different types of C-arm equipment.
Because different grade operation rooms have different levels of cleanliness, we conducted the study to verify whether there were significance differences between the operation field contamination and the different grades of the operation rooms during orthopedic surgeries. Our results showed that there were obvious significant differences between the 1st grade clean operating room (P=0.0204), the 2nd grade clean operating room (P=0.0434), and the 3rd grade clean operating room (Fig. 2A) in terms of operation field contamination. The operation field contamination rate in the 3rd grade clean operating room was significantly higher than that in the 2nd and 1st grade clean operating rooms. Nevertheless, there was no significant difference between the 2nd and 1st grade clean operating rooms.
All the negative control plates showed no bacterial growth in any of the groups, but the positive control plates in every group demonstrated obvious bacterial colonies. Identification of the bacterial colonies showed mainly Staphylococcus epidermidis and Micrococcus luteus, which are conditional pathogenic bacteria (data not shown).
To verify whether a piece of larger C-arm equipment was relevant to a higher rate of operation field contamination, we compared a small C-arm (GE7500, US) with medium C-arm equipment (GE9800, US). There was no significant difference between the operation field contamination and C-arm type (small C-arm: 11.1%, medium C-arm: 14.81%) (P>0.05, Fig. 2B).
3.2 Sterile C-arm drape was irrelevant to operation field contamination.
Our results showed that there were no significant differences in operation field contamination in terms of whether a sterile drape was used (14.81%) or not (11.11%) in the 1st grade clean operating room. Moreover, there was no significant difference between operation field contamination and the relative location of the receiver plate and X-ray tube (P>0.05, Fig. 3A). Similar results were also obtained in the 2nd grade clean operating room (P>0.05, Fig. 3B) and the 3rd grade clean operating room (P>0.05, Fig. 3C). To verify whether C-arm alcohol disinfection could reduce the contamination rate, we used alcohol to sanitize the C-arm, but found no significant difference between group alcohol disinfection (7.41%) and no alcohol disinfection (11.11%) in terms of plate contamination (P>0.05, Fig. 3D).