Exploring the new generation of prosthetics

Posted: 11/19/2010

* Web Produced by: Amanda Nembhard

Cheryl Douglas is re-discovering her kitchen skills. The connoisseur of french cuisine lost both arms and both legs to an infection.

She was in the hospital for three months, rehab for eight. Douglas' re-gaining that independence with this bionic hand. On the I-Limb, each finger moves individually, allowing her to grip objects.

Electrodes attached to the end of cheryl's limb pick up signals from her muscles. A computer inside the hand picks up the signals and directs each finger to move.

Researchers at the University of Pennsylvania are taking prosthetics one step farther: Developing one that moves with the power of the mind. Doctor Douglas Smith and his team grew a mini-nervous system. Their plan: Attach electrodes to the mini nervous system. Transplant it into the spinal cord and it will work like an extension cord -- connecting the patient's thoughts to movements. For someone like cheryl new technology means a new outlook on life.

Doing and living without limits. The I-Limb that Cheryl uses weighs several pounds less than a traditional prosthetic hand. It costs about 18-thousand dollars, and is typically covered by insurance.



BACKGROUND: A prosthesis, prosthetic, or prosthetic limb is an artificial device extension that replaces a missing body part. It is estimated that one out of every 200 people in the U.S. has had an amputation.

TRADITIONAL PROSTHETICS: The pylon is the internal frame or skeleton of the prosthetic limb. The pylon must provide structural support and has traditionally been formed of metal rods. In more recent times, lighter carbon-fiber composites have been used to form the pylons. The pylons are sometimes enclosed by a cover, typically made from a foam-like material. The socket is the portion of the prosthetic device that interfaces with the patient's limb, stump or residual limb. Because the socket transmits forces from the prosthetic limb to the patient's body, it must be meticulously fitted to the residual limb to ensure that it doesn't cause irritation or damage to the skin or underlying tissues. The suspension system is what keeps the prosthetic limb attached to the body. The suspension mechanism can come in several different forms. For example, in the case of a harness system, straps, belts or sleeves are used to attach the prosthetic device. For some types of amputations, the prosthetic is able to stay attached just by fitting around the shape of the residual limb. One of the most common types of suspension mechanisms relies on suction. Though most prosthetic limbs have these basic components in some form, each device is unique and designed for a specific type and level of amputation. ( Source: Amputee Coalition Of America)

BIONIC FUTURE: Investigators at the University for Pennsylvania School of Medicine created a new way to make prosthetics. It’s a biological interface that could link a patient's nervous system to a thought-driven artificial limb. The idea is to use regions of undamaged nervous system tissue to provide command signals to drive a device such as an artificial limb. The challenge is for them to have the prosthetic perform naturally. For example: A patient's thoughts could convert nerve signals into movements of a prosthetics, while sensory stimuli, such as temperature or pressure, provide feedback to adapt the movements. Like an extension cord, the non-electrode end of the lab-grown nervous tissue could integrate with a patient's nerves, relaying the signals to and from the electrode side, in turn connecting them to an electronic device. This system may, one day be able to return function to people who have been paralyzed by a spinal-cord injury, lost limb, or in other ways. (Source: Penn Medicine Press release)