Think of all three legs gos. Maybe you own them or have seen them in the park or in one of the billions of Dodo videos About they. Unequal but resilient, they evoke a kind of dazzling sympathy from humans, which is unmatched by the typical quadruped canine.
“People are attracted to specially adapted pets,” says Rene Agredano, co-founder of the pet amputation support website Tripawds. “I think the attraction is that we just want to help them. We just want to make sure they have the same opportunity to have a happy life. “
Increasingly, this desire to help manifests itself as a prosthesis, especially in cases where the animal has lost more than one limb. Pets with artificial limbs have become a whole genre of videos of their own to feel good. A cat with bionic hind legs. A turtle with wheels. The clips make the rounds on Facebook, where they add a little optimism to the feeling of joy that is in your news feed. 3D printing has propelled the industry forward. Printed prostheses can be lightweight, affordable, and infinitely customizable. Doctors make beaks for birds. High school students build artificial dog paws in their spare time.
But not all pet prostheses are the same. And some veterinarians and people in the tripod community worry that the proliferation of easily workable attachments could cause unwanted consequences for the critters that carry them.
Walking distance
Dogs can lose a limb for several reasons. Maybe they were born with an abnormal limb or were hit by a car or developed cancerous growth that required an amputation. A common joke among tripod lovers is that “dogs have three legs and a spare.” True, up to a point. Dogs adapt remarkably well to the loss of a limb, says Theresa Wendland, who specializes in animal sports medicine and rehabilitation at the Colorado Group of Veterinary Specialists. But complications can arise as the animal makes up for what is missing. In large dogs and with dogs with arthritis or other mobility problems, putting extra weight on the remaining limbs can be a big problem.
“It really affects your spinal mobility,” Wendland says. “They have to change the range of motion of the other limbs. They have to move forward in very unnatural ways. “
The prosthesis, if done well, can restore this range of motion. But as fuzzy as the heart, seeing a three-legged dog run back on all fours, it’s not easy to build a proper puppy leg. Wendland, who works with orthopedic and prosthetic company OrthoPets to help dogs adapt to their new limbs, says it is an involved process that requires time and technical knowledge.
As with human prostheses, an animal prosthesis must be individually tailored to the wearer’s configuration. This means taking into account the size, weight, height, posture and gait of the animal. (A kit for a doberman will not fit in a dachshund.) To do this, orthopedists must study the animal’s movements and try to model one limb that synchronizes with the others. Although the techniques vary, a standard process involves making a plaster mold, designing the prosthesis from photos and video, and then building it with durable thermoplastics and metal. From there, they adjust the details more closely by hand until it works with the animal. The process can take weeks.
There is also the question of how many members need to be replaced. Wendland says the ideal place to put on a prosthesis is as low as possible. But if the whole limb is gone and there is no obvious point in fixing a prosthesis, it will be much more complicated.
A Leg Up
3D printing has long been considered a manufacturing revolution in many industries, including prostheses. And now, a New Jersey-based design company called Dive Design believes it is the solution for replacing integral members. He has partnered with a company called Bionic Pets that builds exactly what its name implies: pet accessibility technology. Derrick Campana, who runs Bionic Pets, has long been building handmade pet prostheses. (He even has a program about it called The magician of the legs, which airs on Brigham Young University TV channel.) About a year ago, he invited Dive Design chiefs Alex Tholl and Adam Hecht to his Virginia lab to see how he could improve the process.
“Something that kept coming up was the need to develop a complete limb prosthesis,” says Tholl. The limbs Campana had been building used too many resources and required too much labor to be manageable. In addition, Tholl says: “With the waste involved, it made no economic sense. For us it was when the wheels started to turn ”.