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

[Pat Barry]

I deleted my post. Sorry about my previous comment

[bridger berdel]

I think for the final edge at least you'll get better results from spyderco uf than diamond.

[John Gornall]

What happened to Canica Designs a surgical tool company started by Leonard Lee the founder of Lee Valley tools after he retired and turned Lee Valley over to his son Rob.

[Andrew Hughes]

I do side work for a friend that assemblys equipment in hospitals. It wasn't too long ago the I walked past a Van parked at the loading dock.Two guys in there shaping or sharpening all kinds of surgical instruments.They each had a half dozen different grinders and several buffers. After I stopped my lusting I thought it standard operating procedure for hospitals.

[Patrick Chase]

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.

An orthopedic surgeon. I should have known :-)

My 3 y/o has a little doctors' kit that she brings whenever she has to go in. A while back she insisted (all on her own) on adding a toy saw and screwdriver to it, so I coached her to say "I'm an orthopedist"
if the doctor ever asked about those. You should have seen the look on the pediatrician's face.


Actually I initially tried for "I'm an orthopedist, would you like an amputation", but that turned out to be a bit much.

[Patrick Chase]

I think for the final edge at least you'll get better results from spyderco uf than diamond.

Yep, but those are ceramic and a tiny bit porous if memory serves, which would tend to rule them out.

Another possibility is some sort of nonporous resinoid stone, though the ones in common use (Shapton, Naniwa SuperStone) don't deal well with prolonged high moisture levels and might have trouble with the disinfection process.

You might also consider a disposable lapping film. Those use resins to stick the abrasive to the polyester backing, but IIRC they're mostly thermosets rather than thermoplastics, so I bet they'd survive the required single trip through the autoclave.

[Robbie Buckley]

Why not use diamond plates and store them in alcohol? Use alcohol for the lubricant as well. Not much lives in 70% ethanol.

[Jake Elkins]

Why not use diamond plates and store them in alcohol? Use alcohol for the lubricant as well. Not much lives in 70% ethanol.


While this would no doubt work (maybe? Some spores, like anthrax, are notoriously tolerant to chemicals), there are usually strict protocols in place for what forms of sterilization work. Additionally, these methods are "tested" with indicators which must be visually confirmed before the instruments are placed in the field, and I am not sure if such an indicator is available for alcohol submersion.

[Lee Schierer]

Correct me if I am wrong, but aren't most diamond sharpening stones made with a plastic matrix filling in the voids in the diamond grid? Most plastics won't take 270 degree temps.

[John K Jordan]

Correct me if I am wrong, but aren't most diamond sharpening stones made with a plastic matrix filling in the voids in the diamond grid? Most plastics won't take 270 degree temps.

Those I have from Woodturners Wonders are diamond grit bonded over the entire surface of a heavy 1/4" thick metal plate, no plastic.

https://woodturnerswonders.com/collections/unique-tools/products/diamond-hones
I see he offers these but I think he can order any size plate and any grit up to at least 1200. I ordered three 3"x8" plates with a different diamond grit on each side. I bought them initially for sharpening ceramic cutters and they worked well.

JKJ

[Patrick Chase]

Correct me if I am wrong, but aren't most diamond sharpening stones made with a plastic matrix filling in the voids in the diamond grid? Most plastics won't take 270 degree temps.

No. Diamond lapping films like the 3M 668X that LV sells are made that way, but plates aren't. The plates use electroplated nickel to "fill the voids" and bond the diamonds to the underlying steel substrate.

The only resin-based diamond plate that I know of is the Shapton flattening plate, but they expressly warn not to use that one on tools precisely because the bond isn't up to the job.

[Patrick Chase]

Those I have from Woodturners Wonders are diamond grit bonded over the entire surface of a heavy 1/4" thick metal plate, no plastic.

Those use electroplated nickel for bonding, just like DMT/Atoma/Trend/iWood/etc.

Now that I think of it I'm not absolutely sure how the EZE-Lap plates are made, so those may be an exception. They certainly have a unique surface color.

[James Waldron]

Yep, but those are ceramic and a tiny bit porous if memory serves, which would tend to rule them out.

Another possibility is some sort of nonporous resinoid stone, though the ones in common use (Shapton, Naniwa SuperStone) don't deal well with prolonged high moisture levels and might have trouble with the disinfection process.

You might also consider a disposable lapping film. Those use resins to stick the abrasive to the polyester backing, but IIRC they're mostly thermosets rather than thermoplastics, so I bet they'd survive the required single trip through the autoclave.

I scrub my Spyderco stones every week or two in dish washing detergent in a sink full of water; if that doesn't clean everything, I dust 'em with Bar Keeper's Friend and scrub with a non-abrasive pad (3M white) that works a charm. When clean, they show a pretty good level of hydrophobicity; droplets run off quickly, but when you can hold it flat enough, droplets bead up with a pretty steep contact angle (a primary measure of hydrophobicity). Never seen any sign of water sinking into the surface, as when rinsed, they drain dry and water rolls right off like a freshly waxed car fender. If they are porous, it would be good to have a cite to a source of this wisdom, if you can recall it.

I'd think a Spyderco medium and ultra-fine in combination would be just what the Doctor ordered. (So to speak.) Since they are all ceramic (Al203), they will have no trouble with sterilization. They are happy being used dry, although a bit of liquid helps manage the swarf. In the OR context, alcohol would do nicely; n-saline would also work well, if the steel instruments are rinsed in pure water and dried afterwards. (n-saline will wet the surface and perform better than pure water.)

[Patrick Chase]

I scrub my Spyderco stones every week or two in dish washing detergent in a sink full of water; if that doesn't clean everything, I dust 'em with Bar Keeper's Friend and scrub with a non-abrasive pad (3M white) that works a charm. When clean, they show a pretty good level of hydrophobicity; droplets run off quickly, but when you can hold it flat enough, droplets bead up with a pretty steep contact angle (a primary measure of hydrophobicity). Never seen any sign of water sinking into the surface, as when rinsed, they drain dry and water rolls right off like a freshly waxed car fender. If they are porous, it would be good to have a cite to a source of this wisdom, if you can recall it.

I don't recall where I got that impression, but note that the fact that liquid water doesn't penetrate something says nothing about its porosity.

A simple counter-example to prove my point: Gore-Tex is highly porous, but liquid water has surface tension far too high to pass through it, at least in the absence of very high pressure. That's sort of the entire point.

[Matt Lau]

Finally a question that I'm qualified to answer!

I'm a dentist, and really hate dull edges.
While hand scalers have traditionally been sharpened with Arkansas stones, I think that ceramics do a better job.
I'm not a huge fan of diamonds aside from major reprofiling of edges--they are too aggressive for my micro-chisels/hoes for onlays.
Surgical instruments tend to be fairly soft IMHO...but Arkansas can be sorta slow and ditch more easily (depending on the quality of the stone).

About 3 years ago, multiple dental suppliers started selling ceramic stones as "new, revolutionary sharpeners" for hygienists.
They'd take a cheaper version of something you'd see from Spyderco or Fallkniven, and sell it for triple the price to dentists.
Considering that these products should be FDA approved, I doubt you'd have issues with surgical use.

I'm not sure how strict your hospital is, but I don't think you'll have trouble sterilizing instruments.
The temperature for my Midmark M9 is about 200 c, which should be way lower than the bonding on diamonds or ceramics.
My SciCan is about 120 C, and used for dental handpieces.

I'll tell you what--I'm going to autoclave my Fallkniven CC4 stone and use it this afternoon.
I'll report afterward work.

[Matt Lau]

I don't recall where I got that impression, but note that the fact that liquid water doesn't penetrate something says nothing about its porosity.

A simple counter-example to prove my point: Gore-Tex is highly porous, but liquid water has surface tension far too high to pass through it, at least in the absence of very high pressure. That's sort of the entire point.

Oh, and fun fact--- Gore made the first membrane for guided bone regeneration (at least in dental).
After the extraction and bone graft, a flap of Gore=tex membrane would be tacked over the graft site to avoid tissue growth into the area.
Later, it'd be taken out.

[Jake Elkins]

I'll tell you what--I'm going to autoclave my Fallkniven CC4 stone and use it this afternoon.
I'll report afterward work.

Awesome Matt - let me know how it works out.

As long as it can go in the tray, I don't think the hospital will care about the sterilization. I hope it works.

[William Fretwell]

Are you getting paid to operate or sharpen tools? You seem to be missing the bigger picture. Operating room time is a premium, the other staff just stand around while you sharpen or do they repair torn scrubs? You guys really crack me up!

[John K Jordan]

Although I know nothing about the medical field I'm glad to see people concerned about their tools.

Decades ago during a procedure (with local) an oral surgeon appeared to be having more trouble and I thought he was using way more force than I thought reasonable cutting through bone. Somehow he managed to shatter the root of a molar which caused intense pain some days later and the need for more extensive surgery. I always wondered if his tools were just dull!

When I had LASIK done almost 20 years ago the eye surgeon impressed me. He said he always prepared and inspected everything himself - he never trusted anyone else to even touch anything. (My eyes are still good!)

JKJ

[bridger berdel]

I scrub my Spyderco stones every week or two in dish washing detergent in a sink full of water; if that doesn't clean everything, I dust 'em with Bar Keeper's Friend and scrub with a non-abrasive pad (3M white) that works a charm. When clean, they show a pretty good level of hydrophobicity; droplets run off quickly, but when you can hold it flat enough, droplets bead up with a pretty steep contact angle (a primary measure of hydrophobicity). Never seen any sign of water sinking into the surface, as when rinsed, they drain dry and water rolls right off like a freshly waxed car fender. If they are porous, it would be good to have a cite to a source of this wisdom, if you can recall it.

I'd think a Spyderco medium and ultra-fine in combination would be just what the Doctor ordered. (So to speak.) Since they are all ceramic (Al203), they will have no trouble with sterilization. They are happy being used dry, although a bit of liquid helps manage the swarf. In the OR context, alcohol would do nicely; n-saline would also work well, if the steel instruments are rinsed in pure water and dried afterwards. (n-saline will wet the surface and perform better than pure water.)

I use isopropyl alcohol as a honing fluid in my shop. It works great on most stones.

[Matt Lau]

Sorry for delay.

The Fallkniven stone works like a champ and cuts smoothly and aggressively on my German steel scalers.
I'd imagine the Spyderco equivalent to work fine too.

Works perfectly fine through autoclave.

[Matt Lau]

I'm not sure if my previous post made it, but the Fallkniven stone works great.
I prefer the ceramic over diamonds for fine sharpening (since your profile should still be usable, otherwise you need a new supplier).
Also, surgical/translucent arkansas work well for standard German steel.

What we do at my office is ultrasonically clean the stones, then wrap in an autoclavable paper sleeve.
371502
Which we put through a Midmark M9 autoclave (pretty standard for most dental offices/vet clinics/hospitals).
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