On the “Cutting Edge”
The pros and cons of cast cutters
I was teaching some of our technicians the proper technique for recasting molds the other day, demonstrating both the casting method and removal method. An odd question came up. A new, prospective technician asked why we use a pneumatic cutter instead of the more common electric cutter. From where I stood, it was obvious, but for the sake of this article, let’s start at the beginning.
In our lab we employ several types of cast cutters. Each has its own unique niche in their various duties in our multi-faceted operation. For every job there’s a tool designed to make that job easier and make you more productive at the end of the day. That’s what it’s all about. It’s no different with cast cutters. Of the three basic types; electric, pneumatic and razor; each has its own place, depending on the job at hand.
The oscillating cast saw is born
The first oscillating cast saw was developed in 1947 by Dr.
Homer Stryker, an orthopedic surgeon from
The most common type of cast cutter is the corded, electric, oscillating kind. Made by companies like Stryker, M-Pact, Hebu and American Orthopeadic, this type of cast saw can be found in almost every medical lab and doctors office around the world. Although similar in design and function from their direct relative the “autopsy saw”, they are less heavy duty and are not waterproof, making these “cast saws” less expensive but not as durable.
I generally regard these saws with some degree of distaste, but that’s just me. When I first started working in a lab setting the electric saws were the only type available. And in our central fabrication facility, we put them thought quite a workout. We used these saws to cut though plastic which had been thermoformed around plaster molds. When using them job after job, hour after hour, they tend to heat up quite a bit. In fact, they can get downright hot! This inevitably leads to burned up bearings and motors, not to mention scorched palms.
Electric saws, though usually durable and well built, are best used in clinical settings where dust contamination isn’t much of a factor and in low production plastic fabrication. It bears mentioning that there is also a cordless, battery powered version, but it’s a little too underpowered to consider for industrial usage, in my opinion.
Another downside to the standard electric cutter is an issue of safety. If you’re working in an environment where water is used, it’s not unlike having a toaster near the bathtub, in my opinion. Even if you’re not touching the water a saw may fall into, you’ll surely ruin the saw. Also, although I’ve never heard of this happening, it does stand to reason that volatile fumes (resin and acetone/thinner) might become ignited by sparks generated by the internal mechanism of electric saws. But this is purely speculative.
The Swissex electric
Another type of electric cutter is more of a specialty item. The Swissex line is electric powered, but they’re more portable due to a belt attachable power pack. This frees up the user to move about unhindered and can be used without consideration of where the power outlet is hiding. This feature is all well and good, but there are two other features which make this cutter truly unique.
The most important of these features, as far as most practitioners will be concerned, is the fact that it is the quietest cast saw, by far. You can easily carry on a conversation with your patient while removing their cast. For most adult patients, it’s just a convenience. But to your average pediatric patient, it makes all the difference in the world. Between the scary blade and the scary noise, the standard cast saw can become every child’s nightmare.
Another wonderful feature when using this cast cuter in a clinical setting, particularly in the hospital or surgical unit, is the fact that the Swissex produces little to no airborne dust. Between the design of the oscillating motor and the unique shape of the saw blade, the cut particles are too large to become easily airborne and fall harmlessly to the ground instead of floating into your lungs and becoming a health hazard. This isn’t such a big deal when cutting plaster casts, but can be a major consideration when cutting off the new generation of fiberglass casting tape. Fiberglass has been identified as a cancerous carcinogen and reducing your exposure to it can only be a good thing.
Because they use compressed air instead of electricity, pneumatic cast cutters also require the availability of an air compressor. Trust me, I’ve tried blowing into the input of one of these things with my mouth and I just can’t get that blade to move at all! This limitation relegates their use primarily to the lab, cutting plastic off from plaster models. Fortunately, though, every decent lab has an air compressor.
One thing to consider when using a pneumatic cutter (or any air tool, for that matter) is that they must have an air discharge. Air comes in one end, makes the tool spin, and then the air must be expelled. Because of this, the discharging air may cause plaster dust to fly all over the place. You’ll want to consider some eye protection. You may also want to rethink using it around patients too.
One of the best things about the air powered cast cutter is its cost. It’s about half of what most electric cutters cost. Most electric saws run in the neighborhood of a grand (give or take a hundred) while the pneumatics cost around $500, unless you buy more than one and then you can save about twenty-five bucks on each.
Another advantage to using this type of saw in the lab setting is the fact that it doesn’t heat up with use, as does the electric type. Rather, it tends to run cold with use. This lengthens the life expectancy of the tool and prevents fatigue to the user’s hands. The thicker air line makes it a little more cumbersome, but it’s still the best choice for production work. And remember, as with all air tools, it requires occasional lubrication.
Only useful in cutting off fiberglass casts, and only the thin ones at that, the razor knife is both quiet and efficient. Since no external power is required for its operation, it can be used absolutely anywhere, including underwater. Not that you would ever want to cut off a cast underwater, but you catch my drift.
The razor cast cutter is one that has a hook shape at the blade. It looks a lot like a carpet cutter or gutting knife used in hunting. This protects the patients’ skin from possible slippage and is much easier to use than a standard razor knife. A straight blade razor knife is not recommended. The standard, garden variety razor knife is, in my humble opinion, just not safe to use on patients. I know several orthotists who use a standard knife, with success (so far), but I just can’t see putting the patient in jeopardy of a nasty cut for no reason. Unless you use the hook type, you might want to avoid razor knives.
Another consideration is durability and maintenance. Most of the electric models, while fairly durable, can be very expensive to repair. Sometimes almost as much as it costs to replace it altogether. Due to the simplicity of its design, the pneumatic variety are very inexpensive and easy to completely rebuilt, if need be. In my opinion, with all things being equal (and they’re not), always use a pneumatic if you can get away with it.
So, which type of cast cutter is best? The answer to that question becomes obvious when you look at the question from a distance. For every job there is the perfect tool. If you remove thin, fiberglass casts, you might want to use the hook knife. If you’re working in the ICU or in the field, you might want to use the Swissex. For cutting plastic off of plaster molds, especially in high production, the pneumatic is for you. For the rest of the time, your electric cutter is still the old standard. Use whichever tool is most appropriate for the job at hand. You see, that way you get to have more tools on your bench, and we all know that the best kind of tool to own is more tools.
This is the sidebar for the article.
It is to our great loss that we bid farewell to Scott
Tracewell, who served on OPTAs board for only a few
months. Although he is currently working in an unrelated industry and no longer
eligible for membership, Scotts contribution to technician education has touched
many. Thankfully, OPTA has been able to draw upon the skill, boundless
enthusiasm and energy of Vince Lebbad, RTP of Tech-Master and Professional
O&P, Inc of
Picture named “pneumatic cast cutter”
A Cooper air power “pneumatic cast saw” in action cutting plastic off a mold.
Picture named “Swissex cast cutter”
The Swissex is lightweight, portable and doesn’t create airborne dust.
Picture named “M-Pact cast cutter” (if it’s worth printing)
M-Pact, Stryker and others make various electric cast cutters.
Cooper (Dotco) pneumatic oscillating saw
Abrasive Specialties & Tools, Inc
Swissex Cast cutters
Stryker and M-Pact electric cast cutters
Southern Prosthetic Supply
Stryker, Cooper (Dotco), American Orthopeadic