Designing medical devices for cleanability. Blog post by Andres Dumas

November 7, 2023

Scientific advances in diagnostics and therapeutics have led to the development of more sophisticated medical devices. These life-changing devices vary in size, geometry, composition, complexity, and sensitivity to cleaning, disinfecting, and sterilizing agents.

Manufacturers of medical devices are required under 21 CFR 801 to support product label claims by providing complete instructions for handling, cleaning, disinfection, testing, packaging, and sterilization, as applicable. Manufacturers also have the responsibility to conduct any testing necessary to validate the suitability of these instructions. Moreover, it is the manufacturer’s responsibility to consider the feasibility and ease of cleaning the device in the intended clinical environment when designing their device.

Why is the device design important from the cleaning perspective?

When performing a cleaning validation following ANSI/AAMI ST98:2022, a worst-case use, and conditions must be simulated to represent the highest challenge to product integrity and safety. This means that the most difficult areas to clean have to be soiled during the study and then the least rigorous cleaning process according to the manufacturer’s instructions has to be applied to remove the soil from the device. If the device has a complex geometry, hard-to-access crevices, porous surfaces, and a complex disassembly process, there is a high chance that cleaning and consequently disinfection and/or sterilization validation will fail, delaying regulatory clearance of the device. 

What factors to consider when designing a new reusable medical device?

To ensure the cleanability of a reusable medical device, several major aspects should be considered during the design process:

1. Risk of patient infection based on intended clinical use: Be aware of the device's classification: non-critical, semi-critical or critical, as each category will have different requirements from the cleanability, disinfection, and/or sterilization perspective.

2. Physical design: Design the device with smooth, non-porous surfaces that are easy to access and clean, while avoiding complex geometries, crevices, and corners where contaminants can accumulate. When possible, design a fully submersible device and isolate electronic components. If the device requires disassembly, ensure the use of the minimum number of components, and an intuitive reassembly.

3. Material design: Choose materials compatible with common cleaning and disinfecting agents, and/or sterilization methods. The chosen material should withstand repeated exposure, without degrading, corroding, discoloring, or losing structural integrity. Some polymers, for example, offer excellent chemical resistance but often provide limited heat resistance. In this case, alternatives such as enhancing the material’s properties, opting for a different polymer or material, or exploring other sterilization methods, such as ethylene oxide or hydrogen peroxide should be considered.

4. Total system design: The impact of repeated cleaning, disinfection, and/or sterilization on the device’s integrity and functionality should also be evaluated. The use of screws, coating, lubricants, and glues for example, can limit the cleaning steps, potentially causing the accumulation of contaminants and consequently impacting the device’s service life.

If your device incorporates complex design features, there are ways to reduce risk while enhancing both accessibility and cleanability. Many modern devices include, for example, ports and channels, O-rings, and articulations. For devices with channels and ports, it's advisable to provide customized brushes as accessories and to flush the channels. When O-rings are part of the device, it's important to establish a routine inspection and maintenance schedule. If the device features articulations, it should be designed to allow full actuation or disassembly during the cleaning process.

If you need consultation regarding the design of your new medical device with a focus on cleaning, disinfection, and sterilization, don't hesitate to reach out to the SteriLabs’ expert team.