Designing for Terminal Sterilization Versus Re-Sterilization

To say that designing an orthopedic device is complex is an understatement. From prototyping and human factors research to regulatory and quality and on to assembly, packaging, and labeling, the process of getting a product to market quickly can be overwhelming.
 
And then there’s sterilization.
 
A big mistake is that sterilization is often relegated to planning later in the development process, with little consideration in product design. While it does take place toward the end of the development process, the number of decisions to make about the type, timing, turnaround, and cost of sterilization can dramatically impact the actual design of the product.
 
In particular is whether a product will call for terminal sterilization (single-use products) or re-sterilization (multi-use, or reusable, products). Easily overlooked, this product distinction is becoming more critical for orthopedic manufacturers to plan for and incorporate into their design. Specific factors that will influence design include:

• Materials: Simply put, a single-use product will generally call for different materials than a reusable product, with the latter requiring materials that are much more robust and that will stand up to reprocessing time and time again. In turn, the choice of materials can affect overall product design. 

• Sterilization Validation: Whether the product will undergo terminal sterilization or re-sterilization, you will need to conduct validation and plan for that in the development process. With a single-use device, validation must show that it can be sterilized twice, to cover two scenarios: if for any reason the sterilization cycle does not work the first time; and to eliminate the risk of losing the product if the shelf life reaches the expiration date and it requires re-sterilization. 

With a multi-use device – or for any single-use device that contains plastic or moving parts – validation must determine the number of times the item can be sterilized.

• Cleaning: The product development process must include cleaning validation for any multi-use product that will be used in the body and subsequently require re-sterilization. From a design perspective, it then usually makes sense to design the product with minimal crevices, corners and sharp edges, and large lumens – all making the device easier, faster, and less expensive to clean. Plus, devices without crevices, corners, and sharp edges have a higher rate of success in sterilization. 

• Use in the Market: For any single-use product, it will be critical to confirm that the hospital (or other end user) can sterilize the product, and to fully understand the cycle that users will employ – and then to design for those.  

Most of the time, sterilization considerations come later versus earlier in the design and development process. Market success, though, comes with design predicated on a deep up-front understanding of user needs and requirements. With sterilization, it’s critical to know your market and understand how users will work with your product, then design accordingly.

Make Smart Decisions

Orthopedic device manufacturers would do well to pay attention to these factors, and “think smart” about how to most efficiently perform terminal sterilization and re-sterilization. Here’s one illustrative example, looking at a manufacturer that developed a kit for bunion surgery. The kit consisted of many jigs and fixtures, all of which were single-use products. It would ship with a set of screws from which the surgeon could choose for the specific procedure.
 
Initially, the manufacturer planned to perform a sterilization validation for the single-use products, but require the hospital to sterilize the screws, given that it would not know which screw sizes would be most popular and most used by the actual users – surgeons.  Instead, the manufacturer heeded a suggestion to just include the largest, heaviest screw in the set in its sterilization validation. That way, if it turned out that a smaller screw was a better fit for the kit, a paper sterilization adoption would allow that substitution. 
 
Result: The company could just run one sterilization validation and retain the flexibility to include any size screw. Performing the sterilization validation once, at their end, instead of once for the reusable products and again for the disposable screws (at the hospital) saved time and money, and increased user satisfaction.

Market Trends

The orthopedic industry is experiencing a movement away from multi-use products as both the FDA and hospitals look for greater efficiency and fewer steps in every process. The time and resources involved in traceability and tracking of multiple parts – common needs with many orthopedic medical devices – are driving the shift.
 
For example, in the case of a screw kit as mentioned above, a hospital would sterilize all unused screws and make them available for the next case if the screws were designed as multi-use. However, that seemingly simple process involves accounting for, counting, tracking, and documenting exactly which screws from the set were used and which are still available, and then restocking the kit. The resources involved in these steps – especially in hospital settings stretched for staff – make designing single-use products a more efficient option. 

Conclusion

Every product is different, but the message to orthopedic manufacturers is to take the time upfront to understand your market, your users, and your sterilization needs at a detailed, meaningful level. That knowledge will drive product design that results in time and cost savings, and the ability to introduce innovative products to the market faster and less expensively. 
 

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Jim Kasic is the founder, president, and CEO of Boulder iQ. With more than 30 years of experience in the Class I, II, and III medical device industry, he holds more than 40 U.S. and international patents. His career includes experience with companies ranging from large multinational corporations to startups with a national and international scope. Kasic has served as president and CEO of Sophono, Inc., a multinational manufacturer and distributor of implantable hearing devices, which was acquired by Medtronic. He also was the president of OrthoWin, acquired by Zimmer-BioMed. He holds a Bachelor of Science in physics and a Master of Science in chemical/biological engineering from the University of Colorado, and an MBA from the University of Phoenix. Contact him at [email protected] or on LinkedIn.