Consider the three legs dog. Maybe you own one, or have seen them in the park or in one of the billion of Dodo videos about their. Unbalanced yet resilient, they evoke a sort of flattering sympathy on our part, humans, unmatched by the typical quadruped dog.
“People are drawn to specially disabled pets,” says René Agredano, co-founder of the Pet Amputation Assistance website. Tripawds. “I think the appeal is that we just want to help them. We just want to make sure they have an equal chance to have happy lives. “
More and more, this desire to help is manifested in the form of prostheses, especially in cases where the animal has lost more than one limb. Animals with artificial limbs have become quite a kind of feel good videos of their own. A cat with bionic hind legs. A wheeled turtle. The clips are doing the rounds on Facebook, where they add a touch of feel-good optimism to the otherwise austere deluge that is your news feed. 3d printing propelled the industry forward. Printed dentures can be lightweight, affordable, and endlessly customizable. Doctors Crafts beaks for birds. High school students build artificial dog paws in their free time.
But not all pet prosthetics are created equal. And some vets and members of the tripod community fear that the proliferation of easy-to-craft accessories has unintended consequences for the creatures that wear them.
Dogs can lose a limb for a variety of reasons. Perhaps they were born with an abnormal limb, or were hit by a car, or developed a cancerous growth that required amputation. A common quip among tripod enthusiasts is that “dogs have three legs and a spare.” This is true, up to a point. Dogs adapt remarkably well to limb loss, explains Theresa Wendland, who specializes in animal sports medicine and rehabilitation. Colorado Veterinary Specialist Group. But complications can arise when the animal makes up for what is missing. In older dogs and dogs with arthritis or other mobility issues, putting extra weight on the remaining limbs can be a big problem.
“It really has an impact on their spinal mobility,” says Wendland. “They have to change the range of motion of their other limbs. They have to move forward in a very artificial way. “
Prosthetics, if done right, can restore this range of motion. But as the heart melts to see a three-legged dog return to racing on all fours, building a proper puppy paw is not easy. Wendland, who works with the orthopedic and prosthetic company OrthoPets to help dogs adjust to their new limbs, says it’s a complex process that takes time and technical know-how.
As with human prostheses, an animal prosthesis must be individually adapted to the morphology of the wearer. This means taking into account the size, weight, height, posture and gait of the animal. (A kit for a doberman is not suitable for a dachshund.) To do this, orthopedists must study the animal’s movements and try to mold a limb that will synchronize with the others. Although techniques vary, a standard process is to make a plaster cast, design the prosthesis from photos and videos, and then build it with durable thermoplastics and metal. From there, they tweak the finer details by hand until it works with the animal. The process can take weeks.
There is also the question of how many members to replace. The ideal place to put a prosthesis, says Wendland, is as low on the limb as possible. But if the whole limb is gone and there is no obvious point to attach a prosthesis, it becomes much more difficult.
One leg in the air
3D printing has long been hailed as a manufacturing revolution in many industries, prostheses among them. And now a New Jersey-based design company called Dive Design thinks it’s the solution for full limb replacement. He partnered with a company called Bionic animals which builds exactly what its name implies: accessibility technology for pets. Derrick Campana, who runs Bionic Pets, has a long history of making handmade pet prosthetics. (He even has a show about it called The Paw Magician, aired on Brigham Young University TV.) About a year ago, he invited Dive Design directors Alex Tholl and Adam Hecht to his lab in Virginia to see how he could improve the process.
“The need to develop full limb prosthetics was a constant recurring issue,” says Tholl. The limbs Campana had built used too many resources and required too much work to be manageable. Further, Tholl says, “With the waste involved, it just didn’t make financial sense. For us, this is where the wheels started to turn.