Engineering the Bionic Person

While many engineers solve problems pertaining to a device or mechanism, it’s not often someone successfully re-engineers the human body, making huge steps in what many engineers and scientists have long dreamed of designing: a bionic person.

But for Dr. Todd Kuiken, 48, director of the Neural Engineering Center for Artificial Limbs at the Rehabilitation Institute of Chicago (RIC), that’s exactly what he’s doing.

And while he’s at it, he’s also making huge strides in changing the way the world looks at prosthetics and those who wear them.

For more than 25 years, Kuiken, a self-described physician scientist who holds doctorates in both medicine and biomedical engineering from Northwestern University, has been mastering a novel technique he developed called Targeted Muscle Reinnervation (TMR). It involves the transfer of residual nerves from an amputated upper limb to unused muscle and skin near the amputation area. Essentially, nerves that at one time went to the amputated arm are re-wired and connected to a non-injured pectoral muscle in the chest. The re-directed nerves then grow into the muscle and the nerve signals are re-directed to the arm via surface electrodes.

This allows patients to control the prosthetic arm by merely thinking about their actions, allowing patients to have much more natural movement of the prosthetic.

“Like other industry-changing events — Ford with automotive, the Wright brothers with aviation and even Gates with technology — Todd’s contributions to the rehab community will help mold the future of that very small group,” says Troy Farnsworth, vice president of the Upper Extremity Prosthetics Program at Hanger Prosthetics and Orthotics, the largest provider of prostheses in the U.S.

Kuiken’s procedure is the first major advancement in prosthetics since World War II. He first performed TMR surgery in 2001 on Jesse Sullivan, a then 56-year-old power lineman from Tennessee who had been electrocuted and lost both his arms. After the surgery, when Sullivan’s nerves grew into his muscle, he regained motor function. Soon, the team discovered he also began to feel nerve sensations, which, according to Kuiken, was a surprise and an added bonus. The development has led to other projects in which Kuiken is devising ways to help patients have more sensory feeling, including vibration and temperature.

With the advent of TMR it became possible for Sullivan to go from using a three-motor prosthetic arm to a six-motor arm. Before TMR, prosthetic arms were only built with three motors. With a six-motor arm, patients have greater motion in the shoulder and forearm area and are able to use several parts of the prosthesis simultaneously.

Kuiken publicly unveiled Sullivan and the success of his procedure in 2005 and continues to further its development.

Kuiken and his invention now play a major part in DARPA’s Revolutionizing Prosthetics 2009 program, a DARPA-funded project organized and led by Johns Hopkins University Applied Physics Lab. and aims to engineer the world’s most advanced prosthetic arm.

Kuiken, who is married and has two young sons, is also an associate professor in the departments of physical medicine and rehabilitation and electrical and computer engineering at Northwestern. He also holds the post of associate dean, representing RIC at the Northwestern University Feinberg School of Medicine.

Kuiken, whose colleagues repeatedly call him selfless and modest, insists the most advanced prosthetic arm to date is a collaborative effort.

“On my own I’ve accomplished a little, but with my clinical and research colleagues, I’ve done a lot,” he says.

“His depth of knowledge, his practical manner and his energy are an inspiration,” says Kevin Englehart, Ph.D., P.Eng., professor of electrical and computer engineering and associate director, Institute of Biomedical Engineering at the University of New Brunswick, who knows Kuiken through extensive research collaborations. “He is the first to celebrate contributions of others with whom he works, ahead of himself.”

Kuiken plans to continue his commitment to changing prostheses through neuroscience and to further sensory development and hopes to use similar techniques to help artificial legs and computerized knees.

“Trying to make people better is our goal, not intellectual properties,” he says. “Our passion is to make a difference.”