Microscopical images of a new unprocessed screw (top left image) alongside two images of screws that have undergone re-processing on numerous occasions (images taken at two different magnifications). Photos by Surgical Materials Testing Laboratory2.
Nothing is better than new. Faultless. Pristine. Clean and unused.
Of course, there can be great value with many reprocessed items. However, like everything else on earth, with simple existence and repeated use begins the inevitable and intractable process of wear.
In surgical circles, wear and fatigue are a particularly important issue with repeatedly re-sterilized medical implants and instruments.
Scrupulous cleaning to rid them of all microorganisms and their possible pathogens before they enter an operating room is a routine procedure. It’s also common practice among hospitals to re-sterilize unused metal implants, such as plates and screws, hundreds and sometimes thousands of times, before they are implanted in a patient.
Just how many times these metal parts undergo these procedures, and what happens to them, is cause for concern and discussion. How clean — and reliable — are implantable medical devices that have undergone repeated re-sterilization?
What are the risks? And what are the alternatives?
The article, “Effect of Cleaning and Sterilization on Titanium Implant Surface Properties and Cellular Response1” noted that the cleaning followed by sterilization can result in altered surface morphology as well as chemistry and suggests that
titanium implants that are re-washed and re-sterilized are not as clean and do not supply the same reliability as do new, never-before-opened, fresh implants.
Additionally, the article “Single-use Screws and Plates2” further reviewed this topic and noted other concerns with repeated re-processing, including:
- Potential for cross contamination
- Inadequate cleaning and decontamination
- Device damage or alteration
- Fatigue-induced failure
While implant contamination can occur in the OR, inadequate cleaning and decontamination crops up from time to time (in part by the sterilization process used, which can result in uneven access to all parts of a device), the condition of re-sterilized devices and instruments and its potential impact on patients is a rising concern.
Re-running trays of screws and plates does leave a potential bioburden behind that could lead to potential complications by way of organic residuals on screws and plates before implantation. This may stimulate an inflammatory response, according to an article on the “Reprocessing of Implantable Screws and Plates in Orthopedic Tray Sets3” by Michelle Alfa, PhD, FCCM.
Dr. Alfa concludes that enough published data supports the concept that organic residues on implantable items do elicit inflammatory responses from reprocessed plates and screws.
Wear and Tear
There is evidence that metals can corrode inside the body and can affect nearby tissues. Metal is susceptible to electrochemical corrosion that can compromise the integrity of the implant.
Implants can also undergo detectible degradation through repeated reprocessing, theoretically increasing the chances of corrosion, thus making metal fatigue and resultant implant breakdown more likely, and potentially affecting implant reliability.
While there are many published papers that report on implant failure, there is still not enough research on the effects of reprocessing on small implants and therefore, the topic warrants more attention.
Eliminating the Issue
Still, even with these anecdotal and theoretical risks, health systems are taking note of all the issues surrounding repeated reprocessing and have decided to act.
For example, previous studies on the subject prompted the Scottish Executive Health Department to state, “Reprocessed steel implants can cause inflammatory reactions to a much greater degree than pristine devices … There are also issues of corrosion and weakening caused by repeated processing.”
As such, orthopedic units in Scotland converted to single-use, pre-sterilized and individually wrapped plates and screws in 2008.
As well, a study out of Australia about the effects of repeated reprocessing of single-use screws in screw caddies revealed “visual proof… of contamination and corrosion”, and called for a change from “the routine use of screw caddies to individually packaged and sterilized plates and screws.4”
So, what are the practical considerations that fall out of these findings? First, the instruments are sterile, eliminating any risk of contamination, meaning that the guarantee of sterility now falls directly on the device manufacturer. When it comes to preventing infection, many healthcare professionals would agree that disposable instruments are safer and more reliable for the patients (by reducing the potential for surgical site infection), staff and liability to their operations.
Then there is the expense. Consider all the hospital and surgical center costs in running their sterilization operation and the related expenditures of staff hours — supplies, cleaning and decontamination — that should be factored into actual implant and instrument costs.
The cost of OR delays are high. Any hint of contamination ensures instruments are returned for reprocessing, potentially causing operating room delays or cancellations. This goes to the heart of a hospital or surgical center’s revenue-earning potential and their ability to provide cost effective patient care.
Finally, there may be the perception that pre-packaged sterile products are more expensive. Factoring in all the potential savings, the actual per-unit cost becomes less of an issue. And as adoption increases, economics will improve with greater demand.
While more definitive clinical study is required on the repeated reprocessing of single-use medical implants and instruments, health professionals are finding more advantages than disadvantages to pre-sterilized devices. In many circumstances, only new will do.
Is adoption of pre-sterilized devices a point of discussion at your hospital?
- Jung Hwa Park, Rene Olivares-Navarrete, Robert E. Baier, Anne E. Meyer, Rina Tannenbaum, Barbara D. Boyan, and Zvi Schwartz, “Effect of Cleaning and Sterilization on Titanium Implant Surface Properties and Cellular Response.” Acta Biomaterialia, 2012 May 8(5): pp. 1966–1975.
- Joanna Ford (R&D Officer, SMTL), Graham Yarlett (HSDU Manager, Royal Glamorgan Hospital), Gill Bailey (Contracts Officer, WHS), & Pete Phillips (Director, SMTL), “Single-Use Screws and Plates,” Surgical Materials Testing Laboratory’s Medidex Medical Device Index, Feb 18, 2013.
- Michelle J. Alfa (2012) “The ‘Pandora’s Box’ Dilemma: Reprocessing of Implantable Screws and Plates in Orthopedic Tray Sets,” Biomedical Instrumentation & Technology: Reprocessing, Vol. 46, No. sp12, pp. 55-59.
- Terry McAuley (2016) “Reprocessing of Singe-use Screws: A Study on the Effects of Repeated Reprocessing on Single-use Screws in Screw Caddies, Steam Consulting.