Related Experiment Video
Updated: May 15, 2026
In Vivo Mouse Model of Spinal Implant Infection
Published on: June 23, 2020
Implant contamination during spine surgery
Jesse E Bible1, Kevin R O'Neill, Colin G Crosby
1Department of Orthopaedics, Vanderbilt Orthopaedic Institute, Vanderbilt University School of Medicine, Medical Center East, South Tower, Suite 4200, Nashville, TN 37232-8774, USA. jesse.bible@vanderbilt.edu
Background Context:
Postoperative spine infections have been reported to occur in 1% to 15% of patients and subsequently lead to significant morbidity and cost, with an elevated risk for instrumented cases. Every effort should be made to minimize the risk of intraoperative wound contamination. Consequently, certain practices are followed in the operating room to prevent contamination, many of which are not evidence based. Conversely, certain objects believed to be sterile are frequently overlooked as potential sources of contamination.
Purpose:
To assess to what degree contamination of spinal implants occurs during spine surgery and evaluate whether coverage of implants alters the rate of contamination.
Study Design:
Prospective study.
Study Sample:
This study included 105 consecutive noninfection surgical cases performed by a single spine surgeon that required the use of instrumentation.
Outcome Measure:
Spinal implant contamination.
Methods:
Cases were randomized to have all implant trays either remain uncovered (n=54) or covered (n=51) with sterile surgical towels on opening until implants were required for the case. After the last implant was placed, a sterile culture swab was used to obtain a sample from all open implants that had been present at the start of the case. The paper outer wraps of the implant trays were sampled in each case as a positive control, and an additional 105 swabs were capped immediately after they were opened to obtain negative controls. Swab samples were assessed for bacterial growth on 5% sheep blood Columbia agar plates. Of note, only departmental funding was used and no applicable financial relationships exist with any author.
Results:
No growth was observed on any of the 105 negative controls, whereas 99.1% of positive controls demonstrated obvious contamination. Cultures from implant samples demonstrated a 9.5% overall rate of contamination with 2.0% (n=1) of covered implants versus 16.7% (n=9) of uncovered implants demonstrating contamination. Length of time implant trays were open before sample collection; implant type (plate, rods, vs. polyetheretherketone), number of scrubbed personnel, and number of implants used were all not found to be significantly associated with implant contamination (p>.05). However, coverage of implants was found to significantly reduce the implant contamination rate (p=.016).
Conclusions:
The contamination of sterile implants during spine surgery was found to occur. However, this contamination was independent of the amount of time the implant trays remained open. Coverage of implants significantly reduces this contamination. Therefore, no matter the expected duration of a case, implant coverage is a simple modifiable way to reduce the risk of intraoperative wound contamination and potentially reduce postoperative infections.
Insights
Covering spinal implants during surgery significantly reduces contamination rates. This simple practice helps minimize intraoperative wound contamination and may lower the risk of postoperative infections in spine surgery patients.
Area of Science:
- Orthopedic Surgery
- Infectious Disease Prevention
- Surgical Safety
Background:
- Postoperative spine infections occur in 1-15% of patients, increasing morbidity and costs, especially in instrumented cases.
- Minimizing intraoperative wound contamination is crucial, yet many current practices lack evidence.
- Sterile objects like implant trays can be overlooked as contamination sources.
Purpose of the Study:
- To quantify spinal implant contamination during surgery.
- To evaluate if covering implants affects contamination rates.
Main Methods:
- Prospective study of 105 spine surgeries requiring instrumentation.
- Randomized comparison of uncovered (n=54) vs. covered (n=51) implant trays.
- Bacterial cultures from implants, positive controls (tray wraps), and negative controls.
Main Results:
- Overall implant contamination rate was 9.5%.
- Covered implants showed 2.0% contamination versus 16.7% for uncovered implants (p=.016).
- Contamination was independent of tray open time, implant type, or personnel number.
Conclusions:
- Spinal implants are susceptible to contamination during surgery.
- Covering implants significantly reduces contamination, regardless of case duration.
- Implant coverage is a simple, effective method to reduce infection risk.
