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Molding miracles

Dave Sisson has been designing prosthetics for over four decades, providing amputees and other clients with a very precious gift: freedom.

Dave Sisson, certified prosthetist and orthotist, works on a patient’s prosthetic arm in his laboratory on Madison’s east side.

Dave Sisson, certified prosthetist and orthotist, works on a patient’s prosthetic arm in his laboratory on Madison’s east side.

Photographs by Sarah Maughan

(page 1 of 2)

From the pages of In Business magazine.

Dave Sisson makes body parts.

As macabre as this sounds, his three-person company, Sisson Mobility Restoration Center in Madison, fabricates prosthetic parts and braces for patients missing limbs due to natural causes, disease, or accidents.

Sisson, a Chicago native, is not a doctor. He was introduced to prosthetics in high school after landing a part-time job as a technician. He went on to study prosthetics and orthotics (supportive braces) at the City College of Chicago and worked for many years at the world-renowned Rehabilitation Institute of Chicago (RIC) — now the Midwest Regional Spinal Cord Injury Center — as a senior staff prosthetist, where he worked on some of the most difficult cases, including a trans-lumbar (pelvis) amputee. 

While there, his youngest patient was still in the womb when doctors discovered she was missing an arm.

He also fitted a 10-month-old child with a myoelectric (sensor-based) movable arm. She adjusted to the device in just 15 minutes by reaching for a toy held in front of her. “You can work with an adult for weeks and never get to that point,” Sisson marvels. “All that intelligence can get in the way.”

But since opening his Madison business in 2000, his work has focused mostly on lower-extremity prosthetics, either above or below the knee. His patients tend to be over 45 and missing one leg below the knee due to diabetes or vascular disease.

Upper-extremity amputees (arms, hands) are less common, Sisson says, although a lot of people are missing fingers. “Typically they’re glued back on.”

Sisson and a technician make everything in house. The art is in casting the perfect fit, he says, especially when it comes to weight-bearing areas.

Temporary legs can cost between $4,000 and $7,000, while permanent versions run between $5,000 and $50,000 on average. Insurance coverage, Sisson reports, “is a pendulum that swings back and forth.”

Extremity makeover

Modern prosthetics are made of aluminum pylons, making adjustments and tweaks much easier than the wooden legs of old.

In the company’s laboratory, dozens of feet — or temporary walking aids — in various sizes, shapes, and levels of flexibility are displayed on shelves. At a worktable in the middle of the room, an outstretched arm reaches outward as if begging for a handshake while several detached leg molds are in various stages of production.

“This business is about mold-making and inverse 3-D images,” Sisson says. “I have a pretty good mind for imagining things turned inside out because I’ve done this for 44 years.”

Over a series of fittings, molds are taken of a person’s residual limb to create a perfectly fitted plastic socket. For a prosthetic leg, a gel liner slips over the patient’s skin to create suction. The patient pulls a sock over the liner and inserts their residual limb into the socket. A coupler and metal pin fit through the bottom of the socket, locking the prosthetic leg in place. Aluminum pylons are used so length and fittings can easily be adjusted as a patient grows or shrinks.

Sisson can make a leg in about a week, but fine-tuning will take multiple visits.

A “foot,” measured in centimeters, is attached at the bottom for stability and its placement relative to the patient’s center of gravity is crucial. Twenty-seven centimeters equals a size-10 shoe.

There are artificial legs for everything — riding a bike, swimming, skydiving, and blades for running — but walking, Sisson explains, should be a subconscious activity. “If you change the equipment, you have to think about every step, which is too much effort, in my opinion. Nobody needs that anxiety.”

Function and fit is his first priority. “My personal bias is toward things that don’t require a lot of maintenance, don’t fail catastrophically, and don’t make noise.”

Protective covers made from moldable, flesh-colored foam can be added as a last step in the process to give a metal prosthetic more of a human form, and decorative skins (stars and stripes, John Deere, Harley-Davidson, for example), can also be added on request.


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