Getting a leg up

3-D printing is helping revolutionize veterinary orthopedics

Photos courtesy Facebook post Nov. 16, 2017, Chi Chi Rescue Dog @ChiChiRescueDog

The use of prosthetics in veterinary medicine is rapidly on the rise, revolutionizing the orthopedic field and enhancing the life of animal patients. While prosthetics have been used in veterinary medicine for more than a decade, the application of these devices in this sector is still relatively new compared to human medicine.

Various factors have spurred this increase. The changing mindset of veterinarians regarding amputation is one of them.

“We have all had the impression that dogs do great on three legs, perhaps because we never had an alternative,” said Patrice Mich, DVM, DABVP, DACVAA, DACVSMR, CCRT, of Wheat Ridge Animal Hospital in Wheat Ridge, Colo. “Amputation is not a benign process.  While it is true most dogs adapt quickly, the long-term effects can be problematic.”

The impact of limb loss may include limited mobility—limb breakdown and chronic neck or back pain, to name a few. Up until now, the profession has come to accept that these are unavoidable consequences, Dr. Mich said. Providing a functional limb can help decrease 
such complications.

This is particularly true in large breed dogs, according to Sherman Canapp, DVM, DACVS, DACVSMR, owner and chief of staff of Veterinary Orthopedic Sports Medicine Group in Annapolis Junction, Md.

“Large breed dogs, especially great Danes and Rottweilers, are so front limb-heavy that if you can preserve a limb, it’s going to be better for the patient long term,” Dr. Canapp said. “You won’t have the compensatory issues and challenges they have with just going for a walk or going up and down the stairs.”

Chi Chi, a golden retriever that was rescued from a dumpster in South Korea in 2016, needed to have all four legs amputated just above each paw. Chi Chi has her own Facebook page where she keeps her fans updated on her progress.

3-D printing, the process of making three-dimensional solid objects from 
a digital file, is also propelling the use 
of prosthetics.

“The cost/barrier of entry for 3-D printing has decreased significantly over the past decade,” said Kyle Snowdon, DVM, DACVS-SA, assistant professor of small animal surgery at the University of Tennessee College of Veterinary Medicine (UTCVM).

A reasonable quality product can be printed on a $300 to $500 machine, he added.

In addition, increased Open Source Software development has made it easier for veterinarians to evaluate various software and convert data from a CT 
or MRI scan into a 3-D model, according to Dr. Snowdon.

“[3D-printing] gives us the opportunity to develop things on a small scale,” said Snowdon, who helped develop a 3-D printing lab at the university. “Traditional manufacturing is expensive and needs to be done in large quantities to offset the upfront cost. [It also] allows us to design implants and tools that better fit our patients.”

Potential patients

Prosthetics can be used for a wide variety of conditions, such as birth defects, injury, or osteosarcoma.

“There are a number of important factors in determining whether an individual patient is a candidate for a device,” Mich said. “A proper diagnosis, biomechanical assessment, and case analysis for appropriateness of prosthesis are required to improve success.”

OrthoPets of Westminster, Colo., works with 20 veterinary rehab clinics on such cases. Prosthetics comprise about 25 percent of the company, orthotics 
75 percent.

“We’re able to help our patients have a longer, active life,” said Amy Kaufmann, CEO of OrthoPets.

The company has worked on more than 15,000 animals (30 species) from around the world, including pets such as Star, a 7-year-old German shepherd, that lost part of her right hind leg at birth, and Naki’o, a red heeler cattle dog, dubbed by media outlets in 2011 to be the first dog to be fitted with a complete set of four prosthetic paws.

The media also recently helped make golden retriever Chi Chi an Internet sensation … she has her own Facebook page keeping the world abreast of her journey with prosthetics.

Chi Chi was rescued from a dumpster in South Korea in 2016, left for dead with wires wrapped around her legs. Due to damaged leg tissue, all four legs had to be amputated just above each paw. She was later flown to the United States through a rescue group where she was then adopted by the Howell family in Phoenix.

The family currently is working toward finding the best fitting prosthetics for Chi Chi. Walking with the help of temporary prosthetics, she is helping cheer up human amputees as a therapy dog.

“[The use of prosthetics] is becoming more of a known thing, by vets and the general public alike, thanks to media attention,” said Andrew Cushing, BVSc, DACZM, assistant professor in zoological medicine at UTCVM. “I’ve had clients ask me about printing prosthetics, based on what they have seen in the news. There’s always so much new information for vets, it’s difficult to keep ahead of the game, but we are always happy to help advise.”

Patches, an endangered black-breasted leaf turtle at Zoo Knoxville in Knoxville, Tenn., received a 3-D printed plastic beak in September 2017 to protect a hole in her nostril from infection and to make it easier to eat.

The 30-year-old female had developed a hole in her nostril in 2016 due to an infection that grew to encompass a portion of her face. After successful treatment with antibiotics, the wound stabilized, but Patches remained susceptible to further infections and had difficulties with food lodging in the area.

Snowdon and Dr. Cushing used CT scans to design the custom mask. The mask was printed using a 3-D printer and fitted to Patches cheek using a screw anchored in dental resin.

The zoo recently reported that she is now eating with ease 
and is expected to continue being a part of the Black-Breasted Turtle Species Survival Plan breeding population.

Patches, a 30-year-old endangered black-breasted leaf turtle at Zoo Knoxville, Knoxville, Tenn., recently received a 3-D printed plastic beak to protect a hole in her nostril from infection and to make it easier to eat. Patches was reportedly doing well at press time and is expected to continue being a part of the Black-Breasted Turtle Species Survival Plan breeding population.
Photo courtesy Zoo Knoxville

A 34-year-old mealy Amazon parrot named Pete may also benefit from a prosthetic. A fox had torn off his foot as he climbed up the side of the backyard aviary.

The short-term goal of closing the wound on Pete’s stump was successful, but there were some long-term complications to take into consideration, according to the University of Pennsylvania School of Veterinary Medicine.

Birds that weigh less than 100 grams tend to do well with one leg. However, once that number increases, birds can experience pain and arthritis in the remaining leg due to the additional weight burden, according to Penn Vet.

“I wanted to see what we could do for Pete with 3-D printing,” said Jonathan Wood, VMD, DACVIM, staff veterinarian in neurology and neurosurgery. “We think about animals that will rehab well and animals that will rehab poorly, similar to people. If there was a parrot that wanted to use what we made for him, Pete seemed to be a good candidate.”

Dr. Wood worked with PennDesign’s Fabrication Lab to design and create the prosthetic. Fourth-year student Gregory Kaiman also assisted.

A few prototypes proved that a prosthetic would indeed be beneficial for Pete, according to PennVet. However, it kept on slipping off when he lifted his leg. At press time, Wood and Kaiman were working on a third design to incorporate a system that securely attaches the prosthetic to Pete’s body.

Moving beyond

3-D printing technology is also used to make custom instruments, custom surgical guides, teaching models, and models that simulate bone for research, according to Snowdon and Cushing.

Prosthetic use in veterinary medicine is on the rise, revolutionizing the orthopedic field and enhancing the life of animal patients.

“The most common use is printing bones prior to surgery for practice and refinement,” Cushing said. “[This allows] us to perfect techniques prior to the real thing and thus produce optimal results and reduce anesthesia time.”

Canapp implements 3-D printing for this use as well, which he said is helping propel orthopedic surgery forward.

When asked what’s new in orthopedics and orthopedic surgery, Canapp noted regenerative medicine, use of stem cells, bioscaffolds, objective gait analysis, and needle scope technology, just to name a few.

“It’s all about holistic and conservative approaches,” he said.

Telemedicine, teletraining, and telecommunication in the veterinary industry also are quickly exploding, according to Canapp.

In the end, it’s about giving pet owners more options. With people viewing their pets more as family members, they are seeking the best in treatments.

“I can speak personally that 65 percent to 75 percent of my case load is from around the country or other countries,” Canapp said. “These are owners willing to travel and think outside the box.”


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