LEWISTON – Most of his patients won’t use their artificial arms and legs to run a marathon or break a world record in swimming, but prosthetist Kevin Carroll knows that some will – and they’ll help all the rest.

“We learn so much working with the athletes, about how they function at the extremes,” said Carroll, a board-certified prosthetist and orthotic designer. “We come up with advances and technologies to help them, and that same technology finds its way into everyday orthotics. And that helps more people.”

Carroll, vice president for Hanger Prosthetics and Orthotics, will be seeing patients Wednesday at the Lewiston branch, 675 Main St., to evaluate their prosthetic limbs.

“It’s just like going to the dentist regularly,” he said. “Most of the time they just need to be reassured that what they’re doing is working. But we have found devices that have failed, like a joint in a knee that broke. They might not even realize that’s the case.”

It’s part of a regular tour Carroll makes to Hanger affiliates throughout the country. He spent part of last week in West Virginia, then traveled to Pennsylvania before returning home to Florida for the weekend. He’ll continue his tour in Maine with stops in Bangor and Lewiston.

It’s an opportunity for area amputees to be seen by a renowned expert. Carroll regularly works with soldiers, Olympic-caliber athletes and has even designed a replacement tail-fluke for an injured dolphin. He just returned from helping amputee athletes at the Beijing Paralympic Games.

But those are not bulk of his patients.

“Most people, if they lose a limb, it’s due to complications from diabetes,” Carroll said Wednesday. “It’s a gradual injury that worsens or a problem that goes untreated.”

Amputations are most common in the lower half of the body, in the legs and feet, since those are normally covered in shoes, socks and pants.

“If it’s on your hand, people might notice and mention it,” he said. “It is easier to ignore if nobody else can see it.”

But Carroll said that working with the extreme cases – the soldiers, the athletes and the dolphin – have helped refine the technology. Winter, the dolphin, has helped develop new ways to attach prosthetic limbs, for example.

Winter was a 4-year-old Atlantic bottlenose dolphin in 2005 when she was caught in a crab trap. She was taken to the nearby Clearwater Marine Aquarium in Florida and treated, but lost the fluke on her tail to her injuries. That’s the horizontal fin on the back of a dolphin’s tale that powers its swimming strokes.

Winter adapted, and learned to swim with side-to-side strokes, but that was damaging her spine. Carroll came in as part of a group to design a prosthetic tail-fluke. Since then, she’s been through 15 versions, each more refined than the last.

“Imagine the force that goes into the body, developing that thrust,” he said. “That’s what we had to design to withstand, and we had to do it without injuring the skin.”

Winter’s first artificial tail was attached to her by a rubber-like tube. That’s evolved into a cup, lined with a special gel, held in place by suction.

“We call it ‘Winter Gel,’ although we probably need a better name,” he said. It’s designed to support and guide the artificial limb while protecting and cushioning the skin. Doctors have started using the gel in the latest generation of orthotics.

And Carroll said Winter has been helpful in other areas.

“In one particular case, I had a soldier who said that if a dolphin can do it, why not him?” Carroll said. “He lost one leg below the hip, the other below the knee and an arm. And he was just sitting in a wheelchair. But now he’s up on prosthetics, and they all rely on that same material.”