Plastic Bags for Sterile Knees - Can this be true?

[Rolande Hall]

This may seem like a question out of the dark ages but it is a real issue with one of my clients.

Normally when creating a sterile barrier pack for orthopedic implants such as knee replacments, I specify the use of thermoformed trays with Tyvek lids and appropriate fitments for product location.

I am working with a device manufacturer who is planning to bring in house his packaging operations. Yesterday I met the sales manager who wants to package his sterile hinge knees in "plastic bags", he says the "big boys do this". He was loud in his assertion that he has seen such packs over recent years and months; the guy is based in the UK.

He means pouches with a peel seal but insists that the "big boys" use transparent film without a breather section. Naturally his boss is thinking he can save lots of Euros.

The devices are Eto sterilised and may travel by unpressurised aircraft so he must have a means for the pack to breath.

It is several years since I was last in a hospital store. Has 'retro' come into fashion and pouch packaging really returned for sterile long stem hinged knees?

Any comments will be appreciated.

 

[MIREGMGR]

Re: Plastic bags for sterile knees. Can this be true?

I don't know what's customary for ortho implants at present. I do know that achieving shipping-cycle validation for the full packaging system for an EtO-sterilized hard heavy object is non-trivial.

We have several products made of only moderately dense materials for which we've had to go to an inner CSR wrap as a cushion/rub-intermediate plus a special pouch of heavier gauge nylon film and heavy gauge spunbond to achieve cycle success, on a not especially strenuous shipping cycle.

Our products generally are cost sensitive disposables. I'd think that for a high value implantable a lidded-tray approach would be pretty sensible.

 

[Doug Tropf]

Re: Plastic bags for sterile knees. Can this be true?

I don't believe a plastic bag without a Tyvek breather could hold up under the vacuums used in eto sterilization. My experience with such bags is they tend to explode or the seams/seals are breached.

 

[chris1price]

Re: Plastic bags for sterile knees. Can this be true?

Hi, I would agree, however, you can get bags with small patches which are permeable to EtO. The sales manager may not have noticed this.
Chris

 

[PaulT]

Re: Plastic bags for sterile knees. Can this be true?

Rolande,

In order for Ethylene Oxide to work, there must some way for the Ethylene Oxide gas to reach the device. It must have a gas permiable material. Tyvek is the most practical and recognized material. Any pouch with tyvek will not have a problem in Air transportation. However, to me the larger issue is the ability of the packaging to withstand the rigors of the transportation testing. The two standards I am familiar with are ISTA 2A and ISO11607. Some of the newer multi layer pouches might stand up to the rigors of the ship testing. But depending upon the weight and size of the device, it might be difficult. That is one reason for the popularity of the thermoformed trays. The rigidity protects the product. Hope this helps.

 

[Rolande Hall]

Re: Plastic bags for sterile knees. Can this be true?

Thanks Paul, I am glad you picked up on the question of ability to withstand transport hazards. This is my main concern. Long stem hinge knees are heavy and if pouch packed I believe that they are likely to damage the sterile barrier pack if dropped. That is why I was surprised to be told that "the big boys" pack them in pouches.
I changed over from pouches to thermoformed trays in the 1970s and find it very surprising that anyone considers a pouch pack appropriate for this type of product.

 

[MIREGMGR]

Re: Plastic bags for sterile knees. Can this be true?

Long stem hinge knees are heavy and if pouch packed I believe that they are likely to damage the sterile barrier pack if dropped.

In our relatively expert engineers' experience, the issue is more likely to be normal-loaded rubbing under forced vibration (which occurs at length in every shipping cycle) rather than dropping per se (which does often occur but is easier to design for). That's why I mentioned our having to use extra-extra-rubthrough-resistant materials when pouching moderately heavy rigid objects. Your customer's engineers' task would be even harder.

I'm surprised they don't get a vote in this design decision. I'd think they'd already have vetoed the pouch approach.

If the customer doesn't have packaging engineers or hadn't been planning to do an engineering project to achieve their ISO 11607 packaging validation, including shipping cycle, I would 100% agree that their urging a pouch approach is naive.

 

[Rolande Hall]

Re: Plastic bags for sterile knees. Can this be true?

Thanks MIREGMGR, maybe I have been lucky but damage due to vibration has rairly been an issue for me.
Dropping has been an issue because of the use of passenger aircraft for distribution. It is a long way down to the tarmac if the guy using his feet to push packages to the open hatch does this when his mate is not looking; at one time this practise led to 8ft drops at London Heathrow.
I take your helpful comments on board, thanks for the insight.

 

[MIREGMGR]

Re: Plastic bags for sterile knees. Can this be true?

Just a clarification of our perspective on this kind of issue: whatever the nature of the hazards in real world transit, it's necessary to pass a technically defined ISTA profile first, to achieve the necessary shipping-cycle validation. All of the likely-acceptable ISTA profiles include shaker time as well as multiple-aspect shock-decelerations.