A review: taking the sterile out of sterility

Users of in-dwelling medical devices, prostheses and surgical dressings rely implicitly on their sterility. Rarely do consumers give any thought to what sterility really means. The general assumption is that manufacturers have adopted the most efficient and cost-effective methods of achieving sterility. Currently, terminal sterilization processes appropriate for the manufacture of medical devices are those that are deemed to give less than one chance in a million of a single, finished product item containing a viable organism. Such a definition of sterility is embodied in the European standard EN556 as a Sterility Assurance Level of 10(-6), based on the properties of heat-resistant endospores. However, is this level of sterility assurance appropriate for all categories of medical device? Moreover, do all medical devices which are labelled as sterile require the same level of treatment? This paper will demonstrate that in some instances, the high standards set for sterilization processing are unreasonable, not cost-effective and exclude new sterilization technologies from being accepted by the regulatory authorities.