DOI: https://doi.org/10.21203/rs.3.rs-965018/v1
Background: intraoperative C-arm fluoroscopy is commonly performed during traumatic orthopedic surgeries. The C-arm sterile drape is often used in cases of contamination of the operative field following postoperative infection. The aim of the present study was to investigate operation field contamination during traumatic orthopedic surgeries and evaluate the factors, especially intraoperative fluoroscopy, which affect operation field contamination.
Methods: sterile 5% sheep blood Columbia agar plates were used to simulate the operation field. The C-arm was moved over the operation field in different grade clean operating rooms, simulating intraoperative fluoroscopy. The agar plates were then incubated and assessed for bacterial colony growth.
Results: our results showed significant differences between the 3rd grade clean operating room and the 2nd or 1st grade clean operating rooms in the risk of operation field contamination. Nevertheless, there were no significant differences in the operation field contamination between the C-arm drape group and the control group.
Conclusions: we conclude that C-arm equipment can be used without the drape during orthopedic surgeries to avoid contact with the operation field.
In cases requiring intraoperative fluoroscopy, an intraoperative X-ray method is commonly used during traumatic orthopedic surgeries, allowing the surgeon to confirm the correct operative levels and assess alignment in multiple planes, monitor fracture reduction, and place instrumentation more accurately [1–5]. The intraoperative fluoroscopy equipment is called the “C-arm,” which may be adjusted to obtain almost any desired radiographic view of the surgical position. However, there is sparse knowledge on the C-arm related postoperative infection during traumatic
orthopedic surgeries.
Postoperative infection remains a serious complication that is common in traumatic orthopedic surgeries. It has been reported to range from 0.8%-6.4%, which has a significant effect on patient healing [6]. Numerous factors are related to infection, including external factors such as increased invasiveness, the length of surgical procedures, the number of circulating personnel in the operating room, and the operating room door openings [7, 8], and internal factors such as morbid obesity, advanced age, poor nutritional status, and an immunocompromised state [9–11]. C-arm equipment might be a source of postoperative infection because it is frequently used during traumatic orthopedic surgery [12], and the C-arm might touch the K-wires or other instruments while taking the fluoroscopy film especially in the lateral view. Generally, the C-arm equipment is covered with a sterile drape to keep the aseptic condition of the operation field[13]. However, studies have shown apparent sterile drape contamination during spinal surgery [14].
According to our clinical experience, the sterile drape was not used during some orthopedic surgeries, such as fracture open reduction and internal fixation operation. Nevertheless, postoperative infection was not observed in these patients after several months of follow-up. The present study aimed to investigate the operation field contamination rate during traumatic orthopedic surgeries and evaluate the factors, especially the sterile drape, affecting operation field contamination.
To simulate the operation field, nine sterile 5% sheep blood Columbia agar plates in every group were placed evenly on the operating table. In every grade of operating room, the experimental group division was based on a sterile drape, the relative location of the receiver plate and X-ray tube, alcohol disinfection, and the size of the C-arm equipment.
The negative control group was placed on a sterile table in the operating room environment during intraoperative fluoroscopy, and the positive control group was obtained by sterile culture swabs that were immediately dipped from the C-arm at the end of fluoroscopy. The C-arm was moved vertically and horizontally over the operation field, simulating intraoperative fluoroscopy in the 1st, 2nd, and 3rd grade clean operating rooms (Fig. 1). The classification of the operating room is based on the number of dust particles from 0.5µm-5µm where the 1st grade clean operating room has < 3500/m³ dust particles, the 2nd grade clean operating room has from 3500-35000/m³ dust particles, and the 3rd grade clean operating room has from 35000-350000/m³ dust particles.
In addition, the number of circulating personnel, the number of door openings, and fluoroscopy time in each group were strictly controlled, ensuring that the results were comparable, and the proper functioning of the air filtration in each operating room was ensured. The surgeon did not touch the C-arm during the operation, and the C-arm operating crew X-rayed the agar plates. The anteroposterior and lateral image fluoroscopy in each group was guaranteed for five minutes. The agar plates were then incubated at 37°C for 48 h and assessed for bacterial colony growth. This was repeated three times for a total of 27 samples from each group.
Data processing and statistical analysis were performed using SPSS software (IBM SPSS Inc., Armonk, NY) using the X2 test with a 5% significance threshold.
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).
The inhibition of specific sources of potential contamination during orthopedic operations is an important method to prevent postoperative infection. There are concerns about C-arm equipment that may be a potential source of contamination and may increase the risk of developing postoperative infection. Based on this, a C-arm sterile drape was used to ensure that the operation field sterility was maintained[15]. However, the sterility of the drape cannot be guaranteed at all times, given the large number of personnel in the operating room, such as radiology technicians, anesthesiologists, nurses, and operation visitors who might inadvertently touch the drape.
Studies have shown a high rate of drape contamination at the end of operative spinal cases, with a 17% contamination rate on initial draping, 50% at 20 min, 57% at 40 min, and 80% at 80 min [13, 16]. Taken together, our data suggest that the drape may not guarantee the operation field sterility. The surgeon may mistaken the drape as sterile, which could cause a potential contamination source in the operation field. Contrary to the information presented above, it will not cause a C-arm source of operation field contamination as long as the C-arm equipment does not touch the operation field. Our study confirmed this hypothesis. The results showed that there were no significant differences in operation field contamination in terms of whether the C-arm drape was used. Thus, C-arm equipment can be used without the drape during orthopedic surgeries to avoid contact with the operation field. A covering sterile sheet in the operation field is an effective measure to prevent the C-arm equipment from directly touching the K-wires or other instruments when taking lateral images. This will not only reduce the waste of the C-arm drape but also save operation time. Above all, conducting an orthopedic operation in a high-grade operating room such as 1st or 2nd grade clean operating rooms could reduce operation field contamination. Moreover, the following measures could also reduce surgical infection: limiting the number of personnel in the operating room and using prophylactic antibiotics.
In summary, there was no effect on contamination of the operation field with the use of a sterile drape. As long as fluoroscopy is performed, C-arm equipment can be used without a drape.
Ethical approval: The study was approved by the hospital ethical review board.
Consent for publication: The authors consent for publication in the Journal of Orthopaedic Surgeries and Research.
Availability of data and materials: The data and materials used to support the findings of this study are available from the corresponding author upon request.
Competing interests: The authors declare no competing interests exist.
Authors’ contributions: Jingjing Dai and Xiaoqing Wang senior authors contributed equally to this work.
Acknowledgements: This work was supported by National Natural Science Foundation of China (grant No. 81871791)