scalpel sharpness?

[billf]

I figure I'll add another surgeon's perspective to the discussion (orthopedic)
As others have previously said, scalpels are basically sharp because they are very thin blades with a very low angle bevel. The majority of the blades I see are poorly finished ( in terms of polish) and vary greatly in how long it takes before they dull into uselessness. But, since they are cheap, I just ask for a new one when it gets too dull. For a hip or knee replacement, I'll go thru 2-3 scalpels, which isn't too good when you compare it to a high quality custom knife, like my RJ Martins!
Remember, OR scalpels are DISPOSABLE, so finishing them to a hign polish would be a waste of $

As far as the amputation Knives, some of them are made from good steel, and they can be sharpened up pretty well, but that depends on who's doing the sharpening. They are not made to cut bone per se, but usually have a profile tough enough to not chip if they hit a bone.

Bill

 

[neosporin]

this is the coolest thread ever i think its time to get off my ass and start sharpening! i've always been wary though, of messing up my knives...

 

[Cyclonejack]

I have heard about obsidian used in scalpels to make, very expensive, and very sharp scalpels. Anyone have info on this?

 

[musashi]

from BritishBlades.com

An obsidian (volcanic glass) edge can be up to 500 times sharper :yikes: than the edge on a surgical scalpel blade of steel, and can be fashioned into the sharpest of any known material either natural or synthetic (as stated by the American Society of Plastic and Reconstructive Surgeons, 1993).
Scanning electron microscopy of the cutting edge of obsidian and surgical steel scalpels demonstrates a straighter and smoother edge with obsidian, although the bevel appears thicker and rougher. Obsidian can be flaked down to one molecule thickness, whereas the steel must be sharpened mechanically or chemically.
Clinical reports claim that incisions made with obsidian demonstrates superior healing and less scar tissue to those made with surgical steel.
In the attached pic the top shows edges of surgical scalpels made of steel (left) and obsidian (right) scanned with electron microscope at x1540.
The scar tissue shown below the edge is scanned at x 65.
At the bottom is an obsidian scalpel made for me by Errett Calahan in 1997. The edge is protected with plastic tape.
Scalpel

 

[Chiro75]

Not only did the obsidian cut better, but the wound healed faster.

 

[billf]

Re: Obsidian scalpels. You can indeed get a finer edge on any "glass" scalpel than on a metal scalpel - the problem is that it is much weaker, and may break off, which is not desirable. Secondly, the two pics of the "scar tissue" are not equivalent in depth, and you cannot prove anything from 1 scar. Scars vary depending on where on the body they are, the age, sex, and racial make-up of the pt, how the wound is closed, and how much pressure (retraction) is placed on the wound edges during the surgery. A skilled plastic surgeon will GENERALLY make a much nicer wound with a steel scalpel than someone else with an obsidian scalpel - having said that I have seen terrible looking scars as a result of beautifully performed surgery because there are factors beyond the control of any surgeon. I have also seen beautiful scars from "badly performed" "home surgery" attempts because the pt was fortunately a very good healer.

Bill

 

[Chiro75]

Bill, you're right, of course, but I believe the report I saw was one of a surgeon who needed surgery himself, so he knapped the obsidian tools for his surgeon, and they thought that they were fantastic and figured the healing was better. Of course every patient and every condition is different, but I assume the surgeons also knew what they're talking about.

 

[billf]

The one I read about ( can't find a link right now) was Errett Callahan, who is a MASTER knapper - I've seen some of his stuff. He had a rotator cuff repair, with the skin incision made with a blade he made for his surgeon, and results were beautiful!
I do about 150 rotator cuff surgeries per year, using the same scalpel types, same incision spot, same suture etc. Most heal great, but about 5/yr or so get keloided and look bad - often in African Americans or Hispanic patients, but not always. There are also about 10/year where I can barely even find the scar after 6 mos, even though I know exactly where it is. Individual variability trumps "tools" every time! While it is true that a sharper blade cuts easier, unless one develops a way to slice"between" the cells, there is no such thing as "atraumatic" surgery.

Eye surgeons use thin diamond scalpels that are awesome, but again they are cutting tissue that is not very tough. As far as the "1 molecule" thick edge - nice idea, show me the evidence!

Bill

 

[Chiro75]

Ah, now that you mention it that's the same guy. I read the thing years ago, so my mind was muddled! Are orthopedists getting into using lasers much for surgery, or does it not create the type of incision a scalpel will (does a surgical laser cauterize as it cuts?)? I've been interested in cold lasers for the type of stuff that we chiropractors deal with pretty regularly, so my mind is on lasers of all kinds these days... Just curious...