Sterile diamond plates?

[Jake Elkins]

I'm an orthopaedic surgeon, and I have been toying with the idea of having a sharpening system that could be used in the operating room. Contrary to popular opinion, many surgical tools are not routinely maintained sharp -- including chisels, osteotomes, etc. These instruments are often used to not just cut bone, but to pound out cement, remove screws, etc. And being a woodworker who dabbles enough in handtools to be dangerous, dull instruments are a pet-peeve. Stones and the like are probably out, since they are porous, and likely to be a challenge to routinely sterilize. I was thinking about diamond plates, but I worry about the adhesives used. Typical sterilization calls for manual and automatic washing, then various cycles of steam treatment at 250-275°F, then a cool-down. Three times per week. It would have to be sterilized with the main instruments for logistical reasons, so gas sterilization procedures, like ethylene oxide are out.

What might work? It never fails to surprise me the collective expertise that posts here, so I figured someone might have an idea. Thanks

[Jim Koepke]

One of the dental assistants locally sometimes sharpens her tools on a small Arkansas stone. She assured me the stone goes through the autoclave between different patients.

My memory is that she uses it dry.

jtk

[Patrick Chase]

I'm an orthopaedic surgeon, and I have been toying with the idea of having a sharpening system that could be used in the operating room. Contrary to popular opinion, many surgical tools are not routinely maintained sharp -- including chisels, osteotomes, etc. These instruments are often used to not just cut bone, but to pound out cement, remove screws, etc. And being a woodworker who dabbles enough in handtools to be dangerous, dull instruments are a pet-peeve. Stones and the like are probably out, since they are porous, and likely to be a challenge to routinely sterilize. I was thinking about diamond plates, but I worry about the adhesives used. Typical sterilization calls for manual and automatic washing, then various cycles of steam treatment at 250-275°F, then a cool-down. Three times per week. It would have to be sterilized with the main instruments for logistical reasons, so gas sterilization procedures, like ethylene oxide are out.

What might work? It never fails to surprise me the collective expertise that posts here, so I figured someone might have an idea. Thanks

Most diamond plates use electroplated nickel to bond the diamonds to the steel substrate. I suspect they could take the treatment you describe, at least for a while. Differential expansion might be an issue in the long run though.

Any concerns about shedding (sterile) micron-sized diamonds in an OR? These bonds are not perfect.

[Patrick Chase]

Thinking about this some more, CBN grinding wheels use the same electroplating technology, and those see thermal cycling more severe than you describe, so it would probably work fine.

[Graeme Lunt]

Wouldn't it be enough to sterilize the instruments after sharpening and before the operation? Why do the stones or whatever have to be in the operating theatre and/or be sterilized? Or are you planning to stop in the middle of an operation to sharpen? Doesn't inspire much confidence if you are not starting the operation with either sharp tools or enough sharp tools to complete the procedure.

[Adam Herman]

i was wondering this as well, but maybe they don't have time to go through the whole process twice? clean and sterilize , sharpen, clean and sterilize. would not want the stones/whatever to get contaminated with the last persons whatever.

[Mark Stutz]

i was wondering this as well, but maybe they don't have time to go through the whole process twice? clean and sterilize , sharpen, clean and sterilize. would not want the stones/whatever to get contaminated with the last persons whatever.

That's what I was initially thinking, but the cost of going thru the cleaning process twice for a set of tools could be prohibitive. Now if you only needed to do this periodically it might be doable.

[Brian Holcombe]

Wouldn't it be enough to sterilize the instruments after sharpening and before the operation? Why do the stones or whatever have to be in the operating theatre and/or be sterilized? Or are you planning to stop in the middle of an operation to sharpen? Doesn't inspire much confidence if you are not starting the operation with either sharp tools or enough sharp tools to complete the procedure.

This is outside of my expertise, but it struck me as being a necessary redundancy.

[Normand Leblanc]

Sharpening can be done wet or dry. Doing it dry implies very small particulates from the sharpening process released in the clean room and I think it's unacceptable. Going wet with water you would most likely need to use USP-WFI (water for injection) or equal water quality otherwise your tool could be contaminated. The stone will have to go in the autoclave quite often...Three times a week doesn't seem very much to me but I'm no expert.

Like you say, porous sharpening stones should not be used but my translucent Arkansas seems to be water proof but I could be wrong.

TBH, I have a hard time thinking that some blades are being sharpen during an operation.

[Jim Koepke]

TBH, I have a hard time thinking that some blades are being sharpen during an operation.

Maybe the doctor just likes to see the look on a patient's face as he runs the scalpel on a steel.

jtk

[Jake Elkins]

The process of sending an instrument back to get sharpened or repaired is a much bigger deal than it seems. Also, many instruments are part of a set, and the hospital may only have a few sets to spare. Thus, if one particular tool is out to get sharpened, and its needed, often an entire new set has to be opened, which is a complete waste of processing. Plus, turn-around-time is measured in weeks. To address another comment above, we often don't know the status of our instruments until they are handed to us. It might be the one we had sharpened last week, or it might be the dinged up chisel used to cut the head off a titanium screw yesterday. The techs who process the dirty instruments do not judge their quality.
Scalpels, sure, everyone expects to be razor sharp, but it is just accepted that certain tools like osteotomes are never particularly sharp. The steel used in these tools are not the hardest, and they are actually easy to sharpen. If I am going to be using a chisel for 30 minutes, it is not unreasonable for me to spend 3-5 minutes sharpening it. Additionally, if I wanted a new "sharper" osteotome opened during a case, it would take at least 5 minutes to get it. And there would be no guarantee that it would be any better.
The metal particulate is not too concerning. We try to avoid it in the joints, but it happens. Sometimes, we need to use a diamond-tipped burr to cut through a total hip implant (which are usually CoCr, very hard). Sparks literally fly.
I have never seen anyone sharpen an instrument in the OR, but it is a thought that has crossed my mind several times in the past few years. Imagine if every time we wanted one of our wood chisels sharpened that we had to send it off, and I think you could appreciate a woodworker-surgeon's frustration. Oh, Jim, our patients are usually asleep when the knives come out

Anyways, its not critical, just something I thought I would query to experts about.

[William Fretwell]

Wouldn't it be enough to sterilize the instruments after sharpening and before the operation? Why do the stones or whatever have to be in the operating theatre and/or be sterilized? Or are you planning to stop in the middle of an operation to sharpen? Doesn't inspire much confidence if you are not starting the operation with either sharp tools or enough sharp tools to complete the procedure.

I'm with you Graeme, start the surgery with the enough tools for the job. Yes particulate contamination leads to granulomas at the very least. Surgeons get paid to operate, someone gets paid much less to sharpen their tools. I'm professionally qualified to sterilise by every method out there. I have a surgeon friend, she uses disposal scalpels and gets through LOTS.

[John K Jordan]

Jake,

There is no adhesive on diamond and CBN wheels and plates, at least not on all that I have seen and use. I don't know the process used but the particles are bonded to the substrate by some metal deposition method. Some particles may break or break loose during sharpening but there is nothing that can't go into an autoclave.

I use a 1200 grit CBN wheel on a Tormek slow speed sharpener. Fine diamond wheels are also available. When I was checking into that wheel I asked the dealer who said the only other one he sold was to a guy who used it to sharpen scalpels. I also have a number of diamond and CBN flat plates in grits up to 1200. All of these wheels and plates are monolithic aluminum or steel with the grit bonded on the surface - none are porous. I haven't sharpened scalpels yet but I have certainly put good edges on a lot of woodturning tools!

A Tormek would be difficult or impossible to sterilize but the diamond and CBN plates should be able to take the cleaning process. Ken Rizza (Woodturner's Wonders) can evidently special order nearly any type, grit, and plate size you want. I had him get some 3"x8" diamond plates with six grits double sided on three steel plates. To prevent rusting perhaps aluminum plates would be better, or ask, he might be able to get them made from stainless steel. It also seems you would have to have a way to polish the edges and that might be the hardest thing (or impossible) to sterilize. (I use a leather honing wheel or strap charged with abrasive compound.)

One issue with wheels might be the type of steel. CBN in particular, and I believe diamond as well, works well with hardened steel such as hardened tool steel and HSS, but are known to "load up" when sharpening mild steel. I have a couple of boxes full of hundreds of surgical tools from the local metal salvaging place and almost all of them appear to be stainless steel. Stainless is not known to be able to take the finest edge. What I don't know is if stainless steel will load up a CBN or diamond plate or wheel. I guess I could pull out some of the used surgical tools and try it.

The surgical tools I have are great for all kinds of things in the shop. I have some of the bone chisels you mentioned, specially calibrated torque wrenches, tiny scissors that look suitable for eye surgery, long scalpels made from rods with tiny cutting edges on the ends, special hammers, special surgical wire and rod, and a big variety of clamps and forceps. A bunch are obviously new. Many of the tools are totally foreign to me and I can only imagine their use. The local hospital occasionally sells them for scrap I buy them at scrap prices but I'll bet they originally cost a fortune! I have vet friends who picked out things they said they could use on animals.

JKJ

[Frederick Skelly]

Dr. Elkins,
It seems like you really need a definitive answer, rather than just my opinion as a user. Have you considered calling DMT or one of the other manufacturers? Maybe just describe the sterilization process and it's frequency and ask their viewpoint?

It's just an idea, but I thought I'd mention it FWIW.

Best regards,
Fred

[Jake Elkins]

Edit*

Thanks for all the ideas. Gives me something to think about