1. Design for reprocessing
For simpler surgical devices, one way to reduce infection risk is to optimise the design of reusable instruments to be more suited to reprocessing methods. This should be applied to both the physical design of the instrument and the instructions provided with it.
Standards guidance on designing reusable surgical devices
There are several key standards that provide guidance on how to physically design reusable surgical devices. AAMI TIR12:2020 provides a list of key design considerations that are important for reuse, including: “risk of patient infection based on intended clinical use; physical design; material selection; human factors; cleaning; total system design; packaging design considerations, if applicable; disinfection; and sterilization.”
Meanwhile, AAMI TIR30:2011/(R)2016 lists a number of instrument design features which are difficult to re-process and which should be avoided.
While these standards are useful tools in your development, they generally focus on the negative features of existing technologies and do not necessarily provide any recommendations for improving surgical sterility.
Evaluating existing surgical devices
Another good place to start when designing a reusable surgical device is by evaluating existing instruments. When reviewing other instruments, consider whether there are any features which make it easy or difficult to clean the device. Most surgical instruments have not changed for decades, if not centuries, so their design may not be optimised for reprocessing. It is useful to talk with the hospital sterile services departments that reprocess these devices. Are there areas that are difficult to access for cleaning after use?
Design principles to promote cleanliness
When designing something which needs to be cleaned, there are several general design rules which can be followed:
- Crevices and hard-to-reach areas where bodily matter can be trapped and not easily cleaned should be removed from the design
- Surfaces should be smooth and easy to wipe clean
- Edges should be rounded wherever the device is not intended to cut or grasp tissue.
Where this is not possible, it is best to avoid introducing any new features which are harder to clean than existing instruments.
Materials are another critical consideration in design for reprocessing. Stainless steel has historically been the material of choice for reusable surgical instruments, but this may not be suitable for the device you are developing. AAMI TIR12 states that “materials used in the construction of devices should be stable in the presence of recommended chemical agents and processing conditions (e.g., temperature, pressure, vacuum, humidity, time).”
Material data sheets may specify that your material is suitable for the cleaning and sterilisation methods you are intending to use, but the component design may not be. Higher temperature sterilisation will cause expansion of the material, for example, which may cause unwanted stresses in your instrument assembly. Different materials have different properties, which may mean that they are suitable for reprocessing on their own but not necessarily when assembled. Careful material selection, calculations, simulation and testing can be used to mitigate the chance of this occurring.
Cleaning, disinfection and sterilisation processes
As with any medical device, the functional design and development alone is not enough. For a reusable medical device, manufacturers must validate their cleaning, disinfection and sterilisation processes to ensure their device is safe for use on the next patient. The process to be followed by hospital reprocessing services must be detailed in the Instructions For Use (IFU) of the device (as required by BS EN ISO 17664-1:2021), which then needs to be followed for validation by the test house. Involving a test house in the development of your IFU is also recommended to increase the likelihood of