A recent article offers readers a review of the latest advancements in upper-extremity bionics and the challenges that remain in creating a prosthesis engineered to meet or exceed the abilities of the human arm and hand. The article appears in the June issue of the Journal of the American Academy of Orthopedic Surgeons (JAAOS).

Douglas T. Hutchinson, MD, associate professor of orthopedics at the University of Utah Medical School, and chief of hand surgery at Primary Children’s Medical Center, the Veterans Affairs Medical Center, and Shriners Intermountain Hospital, states in a news release from the American Academy of Orthopedic Surgeons, that during the next 50 years, “I truly believe we will be able to make artificial arms that function better than many injured arms that doctors are saving today.”

The release notes that one of the most commonly used upper-extremity prosthesis is the myoelectric prosthesis, created more than 50 years ago. It is designed to allow residual muscles to act as natural batteries in order to create transcutaneous signals to control the movements of the prosthetic arm and hand. The muscles most often used are the biceps and triceps, which may not naturally translate to the opening and closing of a hand, according to the release.

As a result of these challenges and the inability to “feel” the prosthesis, the wearer reportedly does not achieve fine motor control, the simultaneous use of multiple joints, or full rotation and use of the hand. The prosthesis, the release says, also required a long period of learning and adjustment.

The release reports that the 2014 federal budget for prostheses research is $2.5 billion. Additionally, the US Department of Defense Advanced Research Projects Agency (DARPA) has invested more than $150 million into their Revolutionizing Prosthetics Program, which is intended to create an upper-extremity prosthesis that will function as a normal human arm does, offering full motor and sensory functions.

Hutchinson points out that the program has given way to several advanced upper-extremity prosthesis, “providing function and ease of learning superior to those of conventional myoelectric prostheses.”

Yet, the release states, these prosthetic devices have a long road ahead for effective and broad use in patients. In addition to heaviness, discomfort, and short-life batteries, another reported challenge in the prosthetic research arena is current infection rates with osseous-integrated devices at the prosthesis-skin interface, which remain at 45%. The issue of efficiently and accurately sending brain signals through the muscles and peripheral nerves of the arms and hands rank as another challenge, the release notes, and this may require the creation and use of a wireless device or direct wiring through an osseous-integrated implant.

A combined effort that blends recent advancements in prosthetic devices with breakthroughs in maintaining nerve and muscle function in badly damaged limbs may pave the way to answers, researchers say.

Hutchinson points out that, “Orthopaedic surgeons who do peripheral nerve surgery (hand surgeons) will be part of the team that puts these devices into patients, but perhaps more relevant than that will be the way we treat severe near amputations or complete amputations differently.  In an amputation surgery, we will need to preserve muscles and nerves even more than we already do to make this type of later reconstruction more successful.”

According to the release, the refinement of nerve utilization could also potentially assist in other conditions such as cerebral palsy (CP), chronic nerve pain, and brachial plexus injuries.”

[Source(s): Science Daily, American Academy of Orthopedic Surgeons]