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My name is Alice and I am a Commodity Consultant for MOCC.
Here is some information I have found out about how prostheses are made:
424 B.C. to 1 B.C.
An artificial leg dating to about 300 B.C. was unearthed at Capua, Italy, in 1858. It was made of bronze and iron, with a wooden core, apparently for a below-knee amputee. In 424 B.C., Herodotus wrote of a Persian seer who was condemned to death but escaped by amputating his own foot and making a wooden filler to walk 30 miles to the next town.
History Prosthetics 02The Roman scholar Pliny the Elder (23-79 A.D.) wrote of a Roman general in the Second Punic War (218-210 B.C.) who had a right arm amputated. He had an iron hand fashioned to hold his shield and was able to return to battle.
The Dark Ages (476 to 1000)
The Dark Ages saw little advancement in prosthetics other than the hand hook and peg leg. Most prostheses of the time were made to hide deformities or injuries sustained in battle. A knight would be fitted with a prosthesis that was designed only to hold a shield or for a leg to appear in the stirrups, with little attention to functionality. Outside of battle, only the wealthy were lucky enough to be fitted with a peg leg or hand hook for daily function.
It was common for tradesmen, including armorers, to design and create artificial limbs. People of all trades often contributed to making the devices; watchmakers were particularly instrumental in adding intricate internal functions with springs and gears.
Renaissance (1400s to 1800s)
The Renaissance ushered in new perspectives of art, philosophy, science and medicine. By returning to the medical discoveries of the Greeks and Romans concerning prosthetics, the Renaissance proved to be a rebirth in the history of prosthetics. Prostheses during this period were generally made of iron, steel, copper and wood.
In 1508, German mercenary Gotz von Berlichingen had a pair of technologically advanced iron hands made after he lost his right arm in the Battle of Landshut. The hands could be manipulated by setting them with the natural hand and moved by relaxing a series of releases and springs while being suspended with leather straps.
Around 1512, an Italian surgeon traveling in Asia recorded observations of a bilateral upperextremity amputee who was able to remove his hat, open his purse, and sign his name. Another story surfaced about a silver arm that was made for Admiral Barbarossa, who fought the Spaniards in Bougie, Algeria, for a Turkish sultan.
Mid- to late 1500s
French Army barber/surgeon Ambroise Paré is considered by many to be the father of modern amputation surgery and prosthetic design. He introduced modern amputation procedures (1529) to the medical community and made prostheses (1536) for upper- and lower-extremity amputees. He also invented an above-knee device that was a kneeling peg leg and foot prosthesis that had a fixed position, adjustable harness, knee lock control and other engineering features that are used in today’s devices. His work showed the first true understanding of how a prosthesis should function. A colleague of Paré’s, Lorrain, a French locksmith, offered one of the most important contributions to the field when he used leather, paper and glue in place of heavy iron in making a prosthesis.
The 17th through 19th centuries
In 1696, Pieter Verduyn developed the first nonlocking below-knee (BK) prosthesis, which would later become the blueprint for current joint and corset devices.
In 1800, a Londoner, James Potts, designed a prosthesis made of a wooden shank and socket, a steel knee joint and an articulated foot that was controlled by catgut tendons from the knee to the ankle. It would become known as the “Anglesey Leg” after the Marquess of Anglesey, who lost his leg in the Battle of Waterloo and wore the leg. William Selpho would later bring the leg to the U.S. in 1839 where it became known as the “Selpho Leg.”
In 1843, Sir James Syme discovered a new method of ankle amputation that did not involve amputating at the thigh. This was welcome among the amputee community because it meant that there was a possibility of walking again with a foot prosthesis versus a leg prosthesis.
History Prosthetics 05In 1846, Benjamin Palmer saw no reason for leg amputees to have unsightly gaps between various components and improved upon the Selpho leg by adding an anterior spring, smooth appearance, and concealed tendons to simulate natural-looking movement.
Douglas Bly invented and patented the Doctor Bly’s anatomical leg in 1858, which he referred to as “the most complete and successful invention ever attained in artificial limbs.”
In 1863, Dubois Parmlee invented an advanced prosthesis with a suction socket, polycentric knee and multi-articulated foot. Later, Gustav Hermann suggested in 1868 the use of aluminum instead of steel to make artificial limbs lighter and more functional. However, the lighter device would have to wait until 1912, when Marcel Desoutter, a famous English aviator, lost his leg in an airplane accident, and made the first aluminum prosthesis with the help of his brother Charles, an engineer.
Moving toward modern times
As the U. S. Civil War dragged on, the number of amputations rose astronomically, forcing Americans to enter the field of prosthetics. James Hanger, one of the first amputees of the Civil War, developed what he later patented as the “Hanger Limb” from whittled barrel staves. People such as Hanger, Selpho, Palmer and A.A. Marks helped transform and advance the prosthetics field with their refinements in mechanisms and materials of the devices of the time.
Unlike the Civil War, World War I did not foster much advancement in the field. Despite the lack of technological advances, the Surgeon General of the Army at the time realized the importance of the discussion of technology and development of prostheses; this eventually led to the formation of the American Orthotic & Prosthetic Association (AOPA). Following World War II, veterans were dissatisfied with the lack of technology in their devices and demanded improvement. The U.S. government brokered a deal with military companies to improve prosthetic function rather than that of weapons. This agreement paved the way to the development and production of modern prostheses. Today’s devices are much lighter, made of plastic, aluminum and composite materials to provide amputees with the most functional devices.
In addition to lighter, patient-molded devices, the advent of microprocessors, computer chips and robotics in today’s devices are designed to return amputees to the lifestyle they were accustomed to, rather than to simply provide basic functionality or a more pleasing appearance. Prostheses are more realistic with silicone covers and are able to mimic the function of a natural limb more now than at any time before.
Source: A BRIEF HISTORY OF PROSTHETICS
The typical prosthetic device consists of a custom fitted socket, an internal structure (also called a pylon), knee cuffs and belts that attach it to the body, prosthetic socks that cushion the area of contact, and, in some cases, realistic-looking skin. Prosthetic limb manufacture is currently undergoing changes on many levels, some of which concern the choice of materials.
A prosthetic device should most of all be lightweight; hence, much of it is made from plastic. The socket is usually made from polypropylene. Lightweight metals such as titanium and aluminum have replaced much of the steel in the pylon. Alloys of these materials are most frequently used. The newest development in prosthesis manufacture has been the use of carbon fiber to form a lightweight pylon.
Certain parts of the limb (for example, the feet) have traditionally been made of wood (such as maple, hickory basswood, willow, poplar, and linden) and rubber. Even today the feet are made from urethane foam with a wooden inner keel construction. Other materials commonly used are plastics such as polyethylene, polypropylene, acrylics, and polyurethane. Prosthetic socks are made from a number of soft yet strong fabrics. Earlier socks were made of wool, as are some modern ones, which can also be made of cotton or various synthetic materials.
Physical appearance of the prosthetic limb is important to the amputee. The majority of endoskeletal prostheses (pylons) are covered with a soft polyurethane foam cover that has been designed to match the shape of the patient's sound limb. This foam cover is then covered with a sock or artificial skin that is painted to match the patient's skin color.
The Manufacturing Process
Prosthetic limbs are not mass-produced to be sold in stores. Similar to the way dentures or eyeglasses are procured, prosthetic limbs are first prescribed by a medical doctor, usually after consultation with the amputee, a prosthetist, and a physical therapist. The patient then visits the prosthetist to be fitted with a limb. Although some parts—the socket, for instance—are custom-made, many parts (feet, pylons) are manufactured in a factory, sent to the prosthetist, and assembled at the prosthetist's facility in accordance with the patient's needs. At a few facilities, the limbs are custom made from start to finish.
Measuring and casting
1. Accuracy and attention to detail are important in the manufacture of prosthetic limbs, because the goal is to have a limb that comes as close as possible to being as comfortable and useful as a natural one. Before work on the fabrication of the limb is begun, the prosthetist evaluates the amputee and takes an impression or digital reading of the residual limb.
2. The prosthetist then measures the lengths of relevant body segments and determines the location of bones and tendons in the remaining part of the limb. Using the impression and the measurements, the prosthetist then makes a plaster cast of the stump. This is most commonly made of plaster of paris, because it dries fast and yields a detailed impression. From the plaster cast, a positive model—an exact duplicate—of the stump is created.
Making the socket
3. Next, a sheet of clear thermoplastic is heated in a large oven and then vacuum-formed around the positive mold. In this process, the heated sheet is simply laid over the top of the mold in a vacuum chamber. If necessary, the sheet is heated again. Then, the air between the sheet and the mold is sucked out of the chamber, collapsing the sheet around the mold and forcing it into the exact shape of the mold. This thermoplastic sheet is now the test socket; it is transparent so that the prosthetist can check the fit.
4. Before the permanent socket is made, the prosthetist works with the patient to ensure that the test socket fits properly. In the case of a missing leg, the patient walks while wearing the test socket, and the prosthetist studies the gait. The patient is also asked to explain how the fit feels; comfort comes first. The test socket is then adjusted according to patient input and retried. Because the material from which the test socket is made is thermoplastic, it can be reheated to make minor adjustments in shape. The patient can also be fitted with thicker socks for a more comfortable fit.
5. The permanent socket is then formed. Since it is usually made of polypropylene, it can be vacuum-formed over a mold in the same way as the test socket. It is common for the stump to shrink after surgery, stabilizing approximately a year later. Thus, the socket is usually replaced at that time, and thereafter when anatomical changes necessitate a change.
Fabrication of the prosthesis
6. There are many ways to manufacture the parts of a prosthetic limb. Plastic pieces—including soft-foam pieces used as liners or padding—are made in the usual plastic forming methods. These include vacuum-forming (see no. 3 above), injecting molding—forcing molten plastic into a mold and letting it cool—and extruding, in which the plastic is pulled through a shaped die. Pylons that are made of titanium or aluminum can be die-cast; in this process, liquid metal is forced into a steel die of the proper shape. The wooden pieces can be planed, sawed, and drilled. The various components are put together in a variety of ways, using bolts, adhesives, and laminating, to name a few.
7. The entire limb is assembled by the prosthetist's technician using such tools as a torque wrench and screwdriver to bolt the prosthetic device together. After this, the prosthetist again fits the permanent socket to the patient, this time with the completed custom-made limb attached. Final adjustments are then made.”
More recently there has been a move to 3D print prosthetic hands which allows people to put tailor their own design.
“Open Bionics is thrilled to announce the next generation of bionic hands.
From the Marvel Universe, hot out of Tony Stark’s workshop, the Iron Man hand.
Artwork designed in collaboration with Lucasfilm’s ILMxLAB and inspired by Lightsabers, the Star Wars lightsaber hand.
Inspired by Queen Elsa from Disney’s Frozen, the Snowflake hand.
Now kids can get excited about their prosthetics. They won’t have to do boring physical therapy, they’ll train to become heroes. They’re not just getting medical devices, they’re getting bionic hands inspired by their favorite characters. The Walt Disney Company is generously donating the time of its creative teams and providing royalty free licenses. More designs coming soon!”