More than Mobility
Since the dawn of humankind, people have found the need to replace their missing limbs with ones that look and work like the real thing. For example, in the case of a missing leg, the ability to regain full mobility and independence is a key concern. However, of equal concern are energy expenditure and psychological factors. Studies that compare the amount of energy a person expends when walking on one leg and crutches, to walking on one leg and one prosthetic leg have shown that people expend considerably less energy when walking on a prosthetic. Furthermore, people who are missing a limb have a much better psychological outlook when the limb is replaced by a prosthetic.
Similarly, mobility, energy, and psychology are all factors that affect animals that are missing limbs. While the art and science of designing and building animal prosthetics has been around for a while, many of today’s prosthetics feature advanced designs with space-age materials that allow animals a range of motion and a degree of freedom that was never before possible.
Mangled by Mankind
Perhaps there is no greater handicap for an elephant than to lose a leg. With the average weight of a male elephant being 9,000 to 13,000 pounds, a missing leg results in total instability, which in the wild is akin to certain death. Other than disease, the odds of an elephant losing its leg to anything other than a human-made trap or mine is highly unlikely.
Humankind is to blame for the amputation that Chhouk, a 5-year old bull elephant from Cambodia, experienced. Chhouk was found close to death in the Cambodian jungle with his front foot mangled in a poacher’s trap. The damage was severe and the elephant lost eight inches of its leg. However, Chhouk was lucky that officials from the Phnom Tamao Wildlife Rescue Center got to him before the poachers did. They fed him, slept with him, and nursed him back to health. When they had done everything they could, they turned to the Cambodian School of Prosthetics and Orthotics – a group of specialists who have refined prosthetic designing skills thanks to the terrible legacy of landmines in Cambodia – and made their plea for Chhouk. This was the first time the specialists had attempted anything on this scale, but they were able to utilize their advanced resources to develop an appropriately sized prosthetic leg from plastic resin that is hard and durable on the outside and soft and comfortable on the inside. “Chhouk, with his new leg, has a completely new persona,” said a wildlife official close to the elephant. “He used to be tired and cranky and now he is lively and constantly moving around.” Chhouk is now on his 5th prosthetic leg, due to extensive wear and tear.
In Thailand, Motola, a majestic 50 year-old female elephant was foraging for food in the forest when she stepped on a landmine placed as part of the ongoing Thai-Myanmar conflict. One of her legs was badly mangled and her owners made an attempt to save it, but it eventually had to be amputated. Now at the Friends of the Asian Elephant Hospital in the Mao Yao National Reserve, Motola is on her third prosthetic. After various initial treatments, Motola wore a temporary device to strengthen her leg muscles and tendons; this prepared her for the prosthesis, which is permanent. The artificial leg was made by the Prostheses Foundation, which also manufactures artificial limbs for human amputees. The hospital is the first of its kind in the world and has treated thousands of elephants with diseases and wounds.
Elephants may rule the animal kingdom, but they are not the only animals that can benefit from prosthetics.
Appendages for All
Body mechanics vary wildly from one species to the next. Consequently, specialists in the field of animal prosthetics have to modify their approach to building prosthetics and do so in creative and innovative ways.
For Beauty, an Alaskan bald eagle, specialists were challenged with designing and attaching a prosthetic beak. Beauty was the victim of poachers who had shot off a large portion of her upper beak, leaving her tongue and sinuses dangerously exposed. She was nursed back to health by volunteers at Birds of Prey NW in Idaho and the center’s founder introduced her to guests at speaking engagements. One of the guests turned out to be an owner at Kinetic Engineering Group (KEG), a team of forward-thinking engineers committed to working on innovative projects. He offered to create a prosthetic for Beauty, taking molds of her stump with the same material used to make dental impressions and then scanning the model into a computer to create a highly accurate 3D mesh model. This helped to determine the size and position of the beak replacement, which was then created out of nylon polymer material. The prosthetic was attached with a titanium and gold mount, but is only a temporary fix. KEG is currently working on a beak that will attach permanently and likely require an implant. Before meeting Beauty, KEG had no prior experience with animals or prosthetics – they were driven simply by the fact that this was a worthy cause.
Winter, a bottlenose dolphin, was only a baby when specialists at the Clearwater Marine Center in Florida rescued her. Her tail got caught in a crab trap and soon it fell off. In fact, she not only lost her tail, but also the peduncle that controls the motion of the tail. She could still use her flippers to move and undulate, similar to a shark, but specialists were concerned about long-term damage her spine might incur from such unnatural motion. Hangar Prosthetics stepped in to create a new tail for the dolphin. Similar to the method used on Beauty, they took a mold of Winter’s stump and then took a 3D scan of the mold. With a digital rendering of the stump, a soft silicone plastic sleeve was than created, carved and fit over the stump. The current model does not take into consideration the missing peduncle, but the specialists are working on a way to recreate it for Winter so the full motion of an actual dolphin tail can be recreated.
Winter has been trained to swim with her new temporary tail and she will continue to get new and improved tails throughout her lifespan.
A Heavy Dose of Mercy
Animals sustain a large number of their injuries due to negligent or cruel behavior by humankind. Their fate is then left in the hands of those who have compassion and who are willing to make amends for our cruelty. It should not be underestimated the amount of time, research, trial, and error it takes to retro-engineer a limb, beak, tail, or other prosthetic; nor the amount of additional suffering, anxiety, and pain an animal endures during the early days of prosthesis. The fact remains that if we didn’t inflict such damage in the first place, we wouldn’t have to go to such great lengths to rectify it.