Ultrasonic Cleaning of Medical Implants

As our population gets older, implant use is skyrocketing. Most of us know someone who has an artificial hip, knee or shoulder. In addition, the number of implant types is growing as medical research provides us with more options to repair damaged and worn out joints.

New Materials and Structures in Medical Implants

Most people think of a plastic or metal ball and socket joint when they picture an implant, but currently you are just as likely to mesh, metal plates, support rods and other structures. They are also being manufactured with an ever-increasing number of materials including plastic and ceramic in addition to the more common metals.

Materials must not only be chosen to meet the use requirement s of strength, flexibility and longevity. They also have to be compatible with the human body – anything that produces an allergic reaction in even a small part of the population has to be rejected out of hand.

And of course the implants have to be absolutely pristine. Any contamination or bio burden could have catastrophic consequences for the patient.

A Difficult Cleaning Application

As you might imagine, this presents some challenges for those responsible for delivering clean implants. Shapes and sizes vary widely, as well as materials of construction and the soils to be removed. This demands a flexible process, and one that can be “tuned” to clean the current part.

To add to the difficulty, the equipment and the cleaning solution have to meet FDA requirements for human implanted devices.

Branson’s Benchmark system is uniquely suited to meet these requirements. Benchmark systems have the flexibility and capacity to meet high-throughput requirements. The system can be configured for computer control of up to 14 tanks, removing much of the possibility of human error and reducing defects.

Requirements for a Medical Device Cleaning System

There are several universally agreed upon requirements for a system to clean medical devices:

• Use of ultrasonics. This can be either with an aqueous or solvent solution or even a combination. The selection is up to the process designer, so long as it meets the FDA guidelines.
• Rinsing tanks must also be sonified. The normal setup is to use overflow tanks and DI water.
• Nitric or citric acid solutions can be used to provide corrosion resistance of oxide films to meet ASTM A 967 or A 380 standards.
• Drying is normally accomplished using an air knife or drying chamber. The air is not only heated, but filtered.
• Finally, the process must be monitored. Data acquisition is paramount, as when something goes awry, you need to be able to look at your process data to see where things went off track.

Below we can see a video of a computerized Benchmark system using sophisticated data acquisition techniques.

The Branson system is one of the most flexible available.

Options / features include:

• Cleaning process automation
• Your choice of 10×12, 12×16, 16×20, 20×24 or custom larger tank sizes
• Integration with auxiliary equipment like filtration, parts handling, bar code scanning
• Cleaning solution monitoring: PH, conductivity, particulate contamination
• Sanitary plumbing
• HEPA filtering for hot-air drying or third party air knives
• Pilot-scale process development for testing prior to full-scale implementation
• On-site water de-ionization capabilities
• Clean-room compatibility

Additional reading and resources:

Five Steps to Validating Cleaning Processes for Medical Devices  Medical Device Summit

Reprocessing of Reusable Medical Devices   FDA.gov

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