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What Are the Newest Advancements in Canine Prosthetics?

When treating dogs for various ailments, oftentimes, there is a limited range of possible options for treatment. Veterinary medicine lags behind human medicine – humans obviously focus on developing medicines for themselves first and foremost – but there are both novel studies in canine medicine and a trickle-down effect of medicine and treatment on other species.

Unfortunately, sometimes, there's still no alternative to an old-fashioned amputation when it comes to certain problems. Limb removal is usually a response to cancer in that limb – particularly cancer in a location that can't be easily removed without complete loss of limb function – but there are other reasons why the surgery may be recommended as well. For example, severe trauma, unstable fractures, deep infections, and even chronic pain can be good reasons to remove the limb.

After all, if the quality of life with the limb is worse than the quality of life without it, it's an easy choice to make.

Of course, advances in veterinary science are also making inroads for treatment options that can save a limb. So-called "limb-sparing treatments" are growing in popularity and efficacy as novel treatments, particularly for cancers like osteosarcoma, are developed and proven effective.

There's only so much a vet can do, though, and sometimes, an amputation is inevitable.

Why Canine Prosthetics?

Prosthetics in humans are common for two main reasons. The first is that we only have so many limbs. We need both legs to walk, so losing one is a huge limitation. A dog, on the other hand, can usually get around just fine with three limbs and, in some cases, even just two, depending on which two remain.

The second reason is that humans have a much more resonant mental body image. We view ourselves as whole the way we are – body dysphoria excepted – and the loss of a limb is consequently a rough emotional and mental adjustment; it's a loss of self. Dogs, meanwhile, don't have that kind of self-perception. A loss of a limb just means a brief period of adapting to a new normal.

Canine prosthetics are an option in some cases, though. They're useful in cases where, for example, both forelimbs or hindlimbs have to be removed, dramatically hampering mobility. They're also useful in extremity amputations where only a paw is removed, leaving most of a leg intact.

Sometimes, quality of life can be just fine without prosthetics. Other times, simple prosthetics make such a large difference that it's a no-brainer to fit them. Advances in prosthetic technology – some of which are pushing the forefront of human medicine – are being made every year.

Transdermal Osseointegration Prosthetic Technology

One advancement in prosthetic technology that has been developed in dogs before being used significantly in human medicine is orthoses using transdermal osseointegration technology. To break down the science terminology, it's a prosthetic that starts internally and integrates directly into the remaining bone of a limb before passing through the skin to an external fitting for a permanent prosthetic.

In a way, this is similar technology to human dental implants. A titanium rod is inserted into the host bone – the jaw in a human or the limb in a dog – and sticks out of the skin to form a post. This post is then used to attach the rest of the prosthetic. The result is something that fits in place, is sturdy and solid as an extension of existing bone, and a functional limb can be maintained.

The alternative to this technology is typically an exoprosthesis. Exoprosthetics are the kind you think of most typically: something strapped to the stump of a limb, secured in place with a brace or harness.

The biggest challenges of both of these kinds of prosthetics come in terms of a few broad categories.

  • Behavioral. Does the dog have a worse quality of life without the prosthetic than they would with it? Do they have behavioral issues that would make them difficult to work with to fit and test a prosthetic? Are they adapted to live without a limb? Some dogs are also unwilling to accept an artificial limb, no matter how much it would improve their mobility.

  • Temporal. How long has it been since the amputation? Dogs that have only recently had an amputation are much more accepting of a prosthetic than dogs that have long since adapted to life without that limb.

  • Size. Mid-sized dogs are generally the best candidates for prosthetics. Small dogs present challenges relating to downsizing the prosthetic appropriately and are often temperamental. Larger breeds put more weight and stress on the prosthetic, which can cause problems down the line.

  • Extent of the prosthetic. A near-total or total limb removal is typically not a good candidate for most prosthetics because there's nothing there to attach a prosthetic to. The more of the limb that remains – particularly if the knee or elbow remains – the better a candidate the dog is for a prosthetic.

Since every dog is different, and every amputation is different, every prosthetic is different. Building prosthetics to the exact specifications necessary for any given patient is, consequently, one of the biggest roadblocks to providing prosthetics on a wider scale.

Advancements in 3D Printing Technologies

Many people have a picture of 3D printing as a cheap technology used by hobbyists to make fragile plastic sculptures. While this is still true for the smallest and cheapest 3D printers, there is a wide range of developments in 3D printing technology. Many veterinary research institutions have been experimenting with 3D printing concepts for prosthetics for over 20 years now.

One of the best advancements in this technology is the use of CT scans and other medical imaging to build 3D renderings of the limb, and then build renders of prosthetics around those limbs, which can then be precisely manufactured using those renderings.

There have also been significant advancements in terms of the techniques and materials used in 3D printing. Instead of a single piece of rigid plastic, 3D printing can now make use of a variety of different materials and structures. The end result is a prosthetic that can be rigid in some places and flexible in others, breathable across the structure, and soft enough to fit comfortably without irritation.

Perhaps the biggest ongoing innovation isn't even advancements in the technology or the materials; it's advancements in knowledge and use. As more and more labs and practices adopt the use of 3D printing, rendering, and scanning, the ability to design and print these prosthetics grows. It's no longer in the realm of a single specialist with a miles-long order sheet for the whole country; it's now much more widespread and available.

That also means one huge benefit: it's getting cheaper. While prosthetics will never be entirely inexpensive, the fact that they can be made much more readily, using more readily available materials and techniques, using technology that costs thousands rather than hundreds of thousands of dollars, using skills that are trainable rather than obscure, all combines to make it much more affordable to the average pet owner. Many businesses, like Bionic Pets, for example, are also bringing customized prosthetics to a more affordable range.

3D printing is also a huge benefit to pets in developing nations, where more conventional prosthetics are simply unavailable. 3D printing designs can be made and adapted readily, and the materials are much more available and less expensive than the alternatives.

Developing Full Limb Prostheses

A challenge in traditional prostheses is full limb support. With a total limb amputation, transdermal osseointegration prostheses can't be done because there's no bone to support the prosthetic. Similarly, limb-extension prosthetics aren't possible with no limb to attach to.

While many dogs are perfectly capable of adapting to life on three legs, it does present challenges, particularly if the amputation happens early in their lifetime. Over time, lopsided support can mean torsional stress on the spine, which can develop into a variety of problems later on in life.

Full limb prosthetics are being developed with increasingly supportive structures and effective shapes. The simplest design typically involves a large, soft cradle to wrap around the shoulder, with a straight support and a wheel that allows for enhanced mobility. While these prosthetics still don't have the complete range of motion or control as a limb would, the additional support can make a huge difference when it comes to spinal stress.

This is another area where 3D printing is making huge strides. Previously, the amount of waste and labor involved in producing a single full-limb prosthetic for a dog was financially untenable. Now, it's dramatically easier and more affordable.

Growing Risks with Prosthetics

The increased ease of producing prosthetics is, unfortunately, coming with an increased risk. Specifically, 3D printing is more and more accessible at regional maker spaces and even home printer setups, and the software necessary to design a prosthetic – and the models already mostly developed – are readily available.

This leads people to frequently believe they can print their own prosthetics or, in some cases, open up their own bootstrapped prosthetics business.

While this increased accessibility isn't necessarily a bad thing, the fact remains that the design needs to be fully customized so it doesn't cause problems, and more importantly, the materials used to create the prosthetic need to be high quality. While something like a wheeled cart for a dog missing both forelimbs is easy, a full-limb prosthetic or even a partial exoprosthetic is tantalizingly within reach without recognizing the potential pitfalls.

These risks are likely to drop as more specialized software is developed and better-quality materials become more readily available. However, there's a middle region between inaccessible and commonplace where the risks and potential harm are high.

The most common problems with these kinds of prosthetics are to the surface where they contact the dog; ill-fitting prosthetics and prosthetics made with sharp edges and abrasive materials can cause skin irritation and ulceration. In extreme cases, this can cause significant enough damage or an infection that can necessitate further surgery. And, of course, there's always the risk that the prosthetic will simply break.

Nerve Connectivity Advancements

One development in prosthetics is entirely within human prosthetics development, at least for now, and that's connections to the nervous system. Cutting-edge developments in prosthetics are enabling thought-controlled limbs and even a return of partial sensation through neuroprosthetics.

For the time being, this technology isn't being used in canine prosthetics. It's much harder to develop and gain feedback from a dog that can't communicate what it feels, after all. However, it's possible that in the future, nerve-connected prosthetics might enable more robust control over a limb and enable feedback that helps with the overall mobility of a dog missing a limb. For now, though, this is largely unexplored territory.

Ongoing Developments in Canine Prosthetics

As time marches on, so too does the progress of medical science, both for humans and for animals. Novel developments and the steady progression of existing technologies will continue, and that's something you can bet on.

One thing that technology can't do for us, though, is make the decisions on when and how a limb needs to be removed. That will always be the realm of trained veterinarians and specialists. In other words, that's your job and ours.

Fortunately, we're here to help. If you have a tricky case like osteosarcoma, an injury, or other trauma, and you need a second opinion to validate that you're making the right decision, we're more than happy to help. All you need to do is sign up for our consultations; then, when you need assistance, simply send us the information you have on the case. We'll send you back a report of our analysis and recommendations, and you can go from there.

As a vet, you have a lot on your shoulders, from routine examinations to emergency care to end-of-life for beloved pets, and all of that can lead to stress and burnout in your own life. Why not offload some of that stress to us? And, if you need counseling on your own stress and burnout, we offer that as well. After all, if you burn out entirely and quit the field, you can't help any more patients, and that's the worst outcome.

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