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Master Your Sterilization Process

Despite the growing use and adoption of disposable instruments, reusable instruments still dominate the orthopaedic market.

At OMTEC® 2015, Jozef Mastej, Vice President of Operations, Gibraltar Laboratories, Inc. outlined the cleaning and sterilization validation process for reprocessing reusable devices. Here are his insights specific to sterilization.

Jozef-head-shot webThe sterilization process must demonstrate an overkill method to ensure that the device is ready to be used again. Sterilization is typically recommended to be performed in three parts.

Part I. Temperature Mapping. Uniformity of temperature distribution throughout the tray must be demonstrated.

Part II. Microbiological Challenge. You must demonstrate a sterilization assurance level 10-6.

First you need to agree what biological indicators (BI) you’re going to challenge for your instrument. Next, you need to ensure you have an appropriate D-value suitable for validation. There are two different documents (AAMI TIR 12 and ANSI/AAMI/ISO 11138-3) that state the two different requirements. AAMI TIR 12 requires a D121 value ≥ 1 minute, and ANSI/AAMI/ISO 11138-3 requires ≥ 1.5 minutes. Which one should you use?

“If you think you want to submit your validation within the U.S. or outside, they’re only going to recognize ANSI/AAMI/ISO 11138-3, which is 1.5 minutes,” Mastej says. “No one is going to accept 1 minute.”

Next, you need to qualify that the biological indicator contains the proper population and determine your placement of BIs within the trays.

“This should always be done between the customer and the lab,” Mastej says “The lab doesn’t always know the end of use of that instrument, the worst case.”

Then you need to choose on your instructions for use (IFU), whether you’re going to use gravity-displacement steam sterilization or the pulsed pre-vacuum steam sterilization, or both.

Time and temperature parameters for gravity-displacement steam sterilization or the post pre-vacuum steam sterilization cycles in health care facilities are outlined in ANSI/AAMI ST79:2010/A4:2013.

“If you want to use a different exposure time, your IFU will most likely not be recognized by FDA,” Mastej says. “Pulsed pre-vacuum sterilization is the most effective sterilization because it has some preconditioning before it gets to the exposure. That is why shorter time is needed to achieve sterilization. With the gravity-displacement steam sterilization, you slowly heat up your vessel pressure and sterilizer before it gets to sterilization.”

Part III. Verification of Drying Time. During this step you must demonstrate that your trays or any devices being wrapped and put in the sterilizer after the specified exposure time and dry time are fully dry with no visible droplets of water.

“If you have one or two drops, FDA defines the containment as non-sterile, so that step is very important,” Mastej says.

Before you wrap a tray, you must weigh your paper. If you’re using a rigid container, the insert goes in the rigid container, and then you load in your sterilizer. This should always be done under maximum load configuration.

After the cycle is completed, you remove your inserts from the rigid container and review to look for any moisture.

“When you have a paper, you unwrap and weigh your paper,” Mastej says. “You cannot gain more than three percent of the moisture in the paper.”

Finally, you inspect your tray. If there are no droplets, then you have a successful validation.

      Quality engineers from Orthofix joined Mr. Mastej in writing a case     
study on Moist Heat Sterilization in April 2013. 
Read it here

Photo courtesy of Gibraltar Laboratories