By: Annie Hu
In recent years, the artificial limbs of science fiction have become a reality. Thanks to the innovation of scientists from across many fields, it has become possible to create highly functional replacements (prosthetics) for missing limbs that allow the user to perform daily tasks like walking, eating, and dressing, with a degree of functionality never before seen. These exciting advances are made possible by new technologies and breakthroughs in prosthetic developments, such as the use of better materials, as well as computers that can receive neuron signals, and have revolutionized the field of prosthetics. It’s almost like science fiction!
Prosthetics evolved primarily as a way to replace limbs lost to injury or sickness, such as after amputation. Originally, prostheses were made from iron, steel, copper, and wood which made them heavy and unwieldy. Ambroise Paré, a French Army surgeon in the 1500s who is regarded as the father of amputation surgery and prosthetic design, introduced many modern amputation techniques and designed several of the first prosthetics. He invented a knee prosthetic that fastened to the wearer with an adjustable harness and attached to an immobile and stable artificial leg. With wars that followed, the need for prosthetics came into the limelight, as more and more people sought ways to restore the functionality of their lost limbs. Advances in technology led to new and better materials for prosthetics, as iron, steel, and copper were replaced by more comfortable and lighter materials like aluminum, plastic, and composite materials. Along with these material advancements, researchers have begun to look into biomechanics, the study of the mechanics of human motion, in order to find ways to return greater functionality by learning how the body naturally creates movement. With a better understanding of the physics and biology of movement, researchers have been able to develop prosthetics that enable people to perform simple yet biomechanically complex tasks.
Other advances in prosthetics focus on the body’s natural electrical signals. Scientists have discovered that even when limbs are amputated, the brain still sends signals to the missing limbs, though they are no longer there to receive them. This is because there are still nerves present at the end of missing limbs. One example of current research in prosthetics is centered around finding ways to channel the signals from working nerves near the site of amputation to a prosthetic capable of picking up the signals. By recreating the electric signals sent by neurons inside a prosthetic, essentially recreating the nervous system of a living limb, it could move and function the way the actual limb would. Limbs that work by using signals from a person’s muscles or brain to facilitate movement are called bionic limbs. Bionics is defined as the study of mechanical systems, particularly those that function like our living systems. The creation of modern bionic limbs involves the collaboration of researchers in many different fields, including electronics, biotechnology, computing, and nanotechnology. Using tools and concepts from each of these disciplines, researchers seek to recreate the interaction of the body’s systems behind the thinking, responding, and doing that go into even our smallest movements. There are different techniques and procedures in developing bionic limbs that are currently being explored. One example of new advances in bionics includes a surgery known as targeted muscle reinnervation. This surgery reattaches nerves into the muscle tissues of the remaining limb to maximize control and facilitate further electronic signaling. Brain impulses from the reattached neurons are then linked to a computer in the limb itself. This results in more efficient movement in a limb that picks up on the messages of the brain in order to work for its user.
There are many other examples of modern prosthetic technologies. One such technology is the development of myoelectric limbs, which use an electronic system in order to control movement. Myoelectric limbs utilize electronic sensors to detect muscle activity at the end of the limb and facilitate the user’s movement, as opposed to bionic limbs, which detect brain activity. These signals are then sent to microprocessors, which are used to facilitate movement. By making muscle movement more pronounced, the wearer can control the strength of the movement. Another example of modern prosthetic technology is osseointegration, which involves attaching a synthetic implant to a living bone in order to promote greater stability and make the limb more comfortable and natural to the user.
The possibilities of using these new technologies to help restore functionality to missing limbs are huge. Modern prosthetics and all the different technologies as well as research that goes into making a limb work are especially exciting, because though we’ve made great advances, there is still much more to discover on the way to fully recreating a biological structure and its ease of function. Modern prosthetics not only help people with missing limbs, but also helps us to understand how our bodies function to carry out even the simplest of tasks, and all the intricate connections and complex interactions that go into our living motions.
Images: Annie Hu