Endotoxins in surgical instruments of hip arthroplasty

Improved surveillance of surgical instruments reprocessing following the variant Creutzfeldt-Jakob disease crisis in England: findings from a three-year survey

BACKGROUND

Sensitive, direct protein-detection methods are now recommended for the inspection of reprocessed reusable surgical instruments in England to reduce the risk of prion transmission.

AIM

To implement an established, highly sensitive method to quantify proteinaceous residues on reprocessed instruments in a Sterile Services Department (SSD) and evaluate its potential impact on service provision.

METHODS

We introduced highly sensitive epifluorescence (EDIC/EF) microscopy in a large SSD. Over three years, we periodically tested two models of washer disinfector using stainless-steel tokens spiked with mouse brain homogenate or Browne test soil for comparison. We also obtained data and feedback from staff who had been using EDIC/EF to examine almost 3000 reprocessed instruments.

FINDINGS

All reprocessed test surfaces harboured residual contamination (up to 258.4 ng from 1-μg spikes). Proximity between surfaces affected decontamination efficacy and allowed cross-contamination. Up to 50 ng de novo proteinaceous contamination was deposited on control surfaces after a single automated washer disinfector (AWD) cycle. The test soil behaved differently than real tissue contamination. SSD staff observed proteinaceous residues on most reprocessed instruments using EDIC/EF, which can detect far smaller amounts than the currently accepted national threshold of 5 μg per side.

CONCLUSIONS

Implementing recent national guidelines to address the prions concern proved an eye-opener. Microscopic levels of proteins remain on many reprocessed instruments. The impact most of these residues, potentially including prions, may have on subsequent patients after sterilization remains debatable. Improving surveillance capability in SSDs can support decision making and raise the standards of surgical instruments reprocessing.

Reprocessing safety issues associated with complex-design orthopaedic loaned surgical instruments and implants

BACKGROUND

The acquisition of reusable surgical instruments (RSIs) through loaner system is a worldwide phenomenon, particularly in orthopaedic surgeries. Loaner sets contain high-complex design RSIs, which are very difficult to clean, and also include single use implants, such as screws, that remain in the surgical tray and are subjected to multiple reprocessing until they are implanted. Inadequate cleaning of SI and various exposures of single-use implants to physical, chemical and biological agents can compromise their quality/safety and promote biofilm formation. The difficulty in cleaning is compounded in middle and low-income countries where automated cleaning infrastructure at sterilizing service units is often unavailable, and thus manual cleaning only is performed. Thus, we aimed to determine the condition of orthopaedic loaned sets when delivered to the hospital, assess the quality of complex-design RSIs reprocessed by manual cleaning, and evaluate the effect of multiple reprocessing on single-use implant (screw).

METHODS

Flexible medullary reamers (FMRs), depth gauges and screws used for femur intramedullary nailing, in clinical use for >1 year, were obtained from three Brazilian loaner companies and assessed for residual ATP, protein, bacterial contamination, endotoxin and/or biofilm at delivery at the hospital, following cleaning and steam sterilisation.

RESULTS

Before cleaning, blood was visible on a RSIs tray, and RSIs/screws were contaminated with high amounts of ATP, protein and bacteria. Visible soil was released during brushing of a FMR lumen and, following cleaning, the inner layer of 34/40 were visible soiled, and over 5/8 were protein test positive. Following sterilisation, biofilm and soil, including fragments appearing to be bone, were detected by scanning electron microscopy on RSIs/screws. A sterilised FMR revealed visible soil on the inner layer. Endotoxin tests were negative.

CONCLUSION

The contaminated condition of loaned-complex-designed RSIs/screws upon arrival at the hospital and after reprocessing points to the insufficiency of manual reprocessing and management practices related to this instruments/implants. A multidisciplinary approach involving expert in design/manufacture, regulating, managing, reprocessing and surgeons is suggested to improve RSIs manufacture that enables complete decontamination and maintain the surgical patient safety.