Surgical Loupes Worn by Orthopaedic Surgeons Are a Reservoir for Microorganisms
Authors: Graham Jack G , Chen Antonia F , Hickok Noreen J , Knott Samantha , Purtill Caroline , Martin Dennis , Beredjiklian Pedro K 
Published: March 2019

Abstract

Background
Surgeons frequently use optical loupes to magnify the surgical field; they are typically unprotected when positioned directly over the wound, where particulate shedding containing microorganisms could potentially lead to surgical site infections (SSIs). SSIs are rare in some orthopaedic subspecialties such as hand surgery; however, in other subspecialties, for example, the spine, where surgeons often use loupes, SSIs can have devastating consequences.

Questions/purposes
(1) What is the degree of bacterial and fungi organism colonization of surgical loupes and storage cases? (2) Is there a difference in the degree of colonization at the beginning and the end of a surgery day? (3) Does an alcohol swab reduce bacterial colonization of surgical loupes?

Methods
The surgical loupes of 21 orthopaedic surgeons from a large, regional orthopaedic practice were cultured over a 3-month period and form the basis of this study. Five loupe storage cases were also cultured. In two different subgroup comparisons, the presence of microorganisms was evaluated just before the start and immediately after the end of the surgical day (n = 9) and before and 1 minute after cleaning with an alcohol swab (n = 6). A total of 36 cultures were evaluated. Surgeons who declined to participate in the study were excluded. The number of loupes selected for all of the analyses were samples of convenience and limited by surgeon availability. The degree of bacterial and fungal presence was graded using a point system: 0 = no growth; 1 = limited growth (meaning few scattered colonies); 2 = moderate growth; 3 = extensive but scattered growth; and 4 = growth consuming the entire plate. Demographic data were assessed using descriptive statistics. Additionally, the Student’s t and Wilcoxon signed-rank tests were used to detect differences in categorical bacterial growth between paired samples. A p value of 0.05 represented statistical significance. Kappa statistics of reliability were performed to evaluate interobserver agreement of microorganism growth in the culture plates.

Results
Bacteria were present in 19 of 21 (90%) sets of loupes. Five species of bacteria were noted. Fungi were present in 10 of 21 (48%) sets of loupes. Bacterial contamination was identified in two storage cases (40%) and fungi were present in five cases (100%). In a subset of nine loupes tested, the degree of bacterial presence had a median of 2 (range, 1-4; 95% confidence interval [CI], 1.0-2.6) in samples collected before starting the surgical day compared with 3 (range, 2-4; 95% CI, 2.0-3.3) at the end of the day (p = 0.004). In a separate study arm comprised of six loupes, 1 minute after being cleaned with an alcohol swab, bacterial presence on loupes decreased from a median of 2 (range, 2-3; 95% CI, 1.9-2.5) to a median of 1 (range, 0-2; 95% CI, 0.5-1.5; p = 0.012).

Conclusions
Loupes are a common reservoir for bacteria and fungi. Given the use of loupes directly over the surgical field and the lack of a barrier, care should be taken to decrease the bacterial load by cleaning loupes and airing out storage cases, which may decrease the risk of surgical field contamination and iatrogenic wound infections.

Clinical Relevance
Routine cleaning and disinfecting of optical loupes with alcohol pads can reduce microorganism colonization and should be implemented by surgeons who regularly use loupes in the operating room. Theoretically, particulate shedding from the loupes into the surgical field containing microorganisms could increase the risk of SSI, although this has not been proven clinically.