Considerations for the technical development of 405nm light for decontamination applications in arthroplasty surgery

Post-operative infection rates following anthroplasty surgery are reported to be as high as 4%, with this rate increasing if patients undergo revision procedures. These infections cause serious patient discomfort and trauma, and have major financial implications due to the increased treatment costs, therefore improved methods of infection control are being sought. Recent studies have demonstrated the application of microbial 405 nm violet-blue light for continuous environmental decontamination of hospital isolation rooms, and this work discusses the technical elements that would be required for optimisation of this technology for application during anthroplasty surgical procedures.
Laboratory studies were firstly conducted to establish the differential sensitivity of mammalian osteoblast and bacterial cells, with exposure times selected to reflect the duration of routine anthroplasty procedures. Cell viability results demonstrated a crtical dose of 36 J/cm² (5 mW/cm² for 2 hours) which was non-detrimental to exposedosteoblasts, but exerted a significant antimicrobial effect - up to 100% reduction - of bacterial pathogens, including Staphylococcus aureus and Staphylococcus epidermidis.Analysis of existing operating theatre lighting was conducted in order to determine its standard optical output, and to investigate how this couldpotentially be altered to provide antimicrobial lighting. Two standard white light sources were tested: a halogen light system, and a light emitting diode system. The spectral output of both sources highlighted the inclusion of 405 nm light in the emission spectra, although at much lower levels than would be required for antimicrobial activity. This study therefore discusses the potential for technical adaptation of existing operating lighting systems and development of new lighting systems which would facilitate 405 nm light decontamination during surgical procedures, thus providing a technology which could potentially be applied as a complementary infection control strategy during surgery.