Artificial limb
484630
223873609
2008-07-06T07:46:14Z
117.201.64.65
/* Cost */
[[Image:Army prosthetic.jpg|right|thumb|300px|A United States soldier demonstrates [[table football]] with two [[Transradial Prostheses|transradial prosthetic]] limbs.]]
An '''artificial limb''' is a type of [[prosthesis]] that replaces a missing [[Limb (anatomy)|extremity]], such as arms and legs. The type of artificial limb used is determined largely by the extent of an [[amputation]] or loss and location of the missing extremity. Artificial limbs may be needed for a variety of reasons, including disease, accidents, and [[congenital defects]]. A congenital defect can create the need for an artificial limb when a person is born with a missing or damaged limb. Industrial, vehicular, and war related accidents are the leading cause of amputations in developing areas, such as large portions of [[Africa]]. In more developed areas, such as [[North America]] and [[Europe]], disease is the leading cause of amputations.<ref name="one">[http://www.bmj.com/cgi/content/full/323/7315/732#SEC2 "Science, Medicine, and the Future: Artificial Limbs"], [[BMJ]], 29 September 2001. Retrieved 11 February 2007.</ref> Cancer, infection and [[Cardiovascular disease|circulatory disease]] are the leading diseases that may lead to amputation.<ref name="two">[http://www.uihealthcare.com/depts/medmuseum/wallexhibits/body/histofpros/histofpros.html "History of Prostheses"], [[University of Iowa]], 5 June 2006. Retrieved 11 February 2007.</ref>
==History==
[[Image:Goetz-eiserne-hand.jpg|thumb|The iron prosthetic hand worn by [[Götz von Berlichingen]] from 1508 (1861 etching).]]
[[Image:MWP Sowinski.JPG|thumb|right|Wooden leg of Gen. [[Józef Sowiński]]; from early 19th century]]
An artificial limb is '''mythologically referred''' to in the [[Rigveda]], the "iron leg" given to [[Vishpala]] by the [[Ashvins]]. The first specimen discovered archaeologically, known as the [[Roman Capua Leg]], was found in a tomb in Capua, Italy, dating to [[300 BC]], and was made of copper and wood.<ref name="Cairo_Toe">[http://news.bbc.co.uk/2/hi/health/6918687.stm "Cairo toe earliest fake body bit"], BBC News, 27 July 2007. Retrieved 27 July 2007.</ref> Two artificial toes found on Egyptian mummies are even older, dating to 1295–664 BC; these are being tested (as of July 2007) to determine whether they could have been used in life.<ref name="Cairo_Toe"/> [[Armorer]]s in the 15th and [[16th century|16th centuries]] made artificial limbs out of iron for soldiers who lost limbs. Over the next several centuries, craftsmen began to develop artificial limbs from wood instead of metal because of the lighter weight of the material.
In the 19th century, artificial limbs became more widespread due to the large number of amputees from wars such as the [[Napoleonic Wars]] in Europe and the [[American Civil War]]. In the latter, a [[Confederate States of America|Confederate]] soldier, [[J.E. Hanger]], who had himself suffered the war's first [[amputation]] (see [[Battle of Philippi (West Virginia)|Battle of Philippi]]) founded what was for a time the world's largest artificial limb factory.
Technology improved primarily for two reasons: the availability of government funding and the discovery of [[anesthetics]]. After [[World War II]], the Artificial Limb Program was started in 1945 by the [[United States National Academy of Sciences|National Academy of Sciences]]. This program helped improve artificial limbs by promoting and coordinating [[Scientific method|scientific research]] on prosthetic devices.
In recent years, a great deal of emphasis has been placed on developing artificial limbs that look and move more like actual human limbs. Advances in [[biomechanical]] understanding, through the combined work of [[medical doctor|doctors]] and [[engineer]]s, the development of new [[plastic]]s, and the use of [[computer aided design]] and [[computer aided manufacturing]] have all contributed in the development of more realistic artificial limbs.<ref name="two">[http://www.uihealthcare.com/depts/medmuseum/wallexhibits/body/histofpros/histofpros.html Exhibits Throughout the Hospital: The Medical Museum: University of Iowa Health Care:<!-- Bot generated title -->]</ref><ref name="three">[http://www.madehow.com/Volume-1/Artificial-Limb.html "Artificial Limb"], How Products are Made, 2007. Retrieved 11 February 2007.</ref>
==Types==
[[Image:Wtcrun-001.jpg|right|thumb|A [[United States Marine Corps|United States Marine]] with bilateral prosthetic legs leads a formation run.]]
There are four main types of artificial limbs. These include the [[transtibial prosthesis|transtibial]], [[transfemoral prosthesis|transfemoral]], [[transradial prosthesis|transradial]], and [[transhumeral prosthesis|transhumeral]] prostheses. The type of prosthesis depends on what part of the limb is missing.
===Transtibial Prosthesis===
A [[transtibial prosthesis]] is an artificial limb that replaces a leg missing below the knee. Transtibial amputees are usually able to regain normal movement more readily than someone with a transfemoral amputation, due in large part to retaining the knee, which allows for easier movement.
===Transfemoral Prosthesis===
A [[transfemoral prosthesis]] is an artificial limb that replaces a leg missing above the knee. Transfemoral amputees can have a very difficult time regaining normal movement. In general, a transfemoral amputee must use approximately 80% more energy to walk than a person with two whole legs.<ref name="four">[http://www.abc.net.au/science/slab/leg/default.htm "Getting an Artificial Leg Up"], [[Australian Broadcasting Corporation]], 2000. Retrieved 11 February 2007.</ref> This is due to the complexities in movement associated with the knee.
===Transradial Prosthesis===
A [[transradial prosthesis]] is an artificial limb that replaces an arm missing below the elbow. Two main types of prosthetics are available. Cable operated limbs work by attaching a harness and cable around the opposite shoulder of the damaged arm. The other form of prosthetics available are [[myoelectric]] arms. These work by sensing, via [[electrode]]s, when the muscles in the [[Arm|upper arm]] moves, causing an artificial hand to open or close.
===Transhumeral Prosthesis===
A [[transhumeral prosthesis]] is an artificial limb that replaces an arm missing above the elbow. Transhumeral amputees experience some of the same problems as transfemoral amputees, due to the similar complexities associated with the movement of the elbow. This makes mimicking the correct motion with an artificial limb very difficult.
==Current Technology/Manufacturing==
In recent years there have been significant advancements in artificial limbs. New plastics and other materials, such as [[carbon fiber]], have allowed artificial limbs to be stronger and lighter, limiting the amount of extra energy necessary to operate the limb. This is especially important for transfemoral amputees. Additional materials have allowed artificial limbs to look much more realistic, which is important to transradial and transhumeral amputees because they are more likely to have the artificial limb exposed.<ref name="three">[http://www.madehow.com/Volume-1/Artificial-Limb.html How artificial limb is made - Background, Raw materials, The manufacturing process of artificial limb, Physical therapy, Quality control<!-- Bot generated title -->]</ref>
In addition to new materials, the use of electronics has become very common in artificial limbs. Myoelectric limbs, which control the limbs by converting muscle movements to electrical signals, have become much more common than cable operated limbs. Myoelectric limbs allow the amputees to more directly control the artificial limb. Computers are also used extensively in the manufacturing of limbs. [[CAD/CAM|Computer Aided Design and Computer Aided Manufacturing]] are often used to assist in the design and manufacture of artificial limbs.<ref name="three">[http://www.madehow.com/Volume-1/Artificial-Limb.html How artificial limb is made - Background, Raw materials, The manufacturing process of artificial limb, Physical therapy, Quality control<!-- Bot generated title -->]</ref>
Most modern artificial limbs are attached to the stump of the amputee by belts and cuffs or by [[suction]]. The stump usually fits into a socket on the prosthetic. The socket is custom made to create a better fit between the leg and the artificial limb, which helps reduce wear on the stump. The custom socket is created by taking a plaster cast of the stump and then making a mold from the plaster cast. Newer methods include laser guided measuring which can be input directly to a computer allowing for a more sophisticated design.
One of the biggest problems with the stump and socket attachment is that there is a large amount of rubbing between the stump and socket. This can be painful and can cause breakdown of tissue.<ref name="four">[http://www.abc.net.au/science/slab/leg/default.htm Getting an artificial leg up - Cathy Johnson<!-- Bot generated title -->]</ref>
Artificial limbs are typically manufactured using the following steps:<ref name="three">[http://www.madehow.com/Volume-1/Artificial-Limb.html How artificial limb is made - Background, Raw materials, The manufacturing process of artificial limb, Physical therapy, Quality control<!-- Bot generated title -->]</ref>
#Measurement of the stump
#Measurement of the body to determine the size required for the artificial limb
#Creation of a model of the stump
#Formation of [[thermoplastic]] sheet around the model of the stump – This is then used to test the fit of the prosthetic
#Formation of permanent socket
#Formation of plastic parts of the artificial limb – Different methods are used, including [[vacuum forming]] and [[injection molding]]
#Creation of metal parts of the artificial limb using [[die casting]]
#Assembly of entire limb
==Emerging Technology==
There are several areas of technology that have advanced significantly in recent years and are showing considerable potential. Robotic limbs and direct bone attachment are two new technologies that have made tremendous gains recently.
===Robotic Limbs===
Advancements in the processors used in myoelectric arms has allowed for artificial limbs to make gains in fine tuned control of the prosthetic. The Boston Digital Arm is a recent artificial limb that has taken advantage of these more advanced processors. The arm allows movement in five axes and allows the arm to be programmed for a more customized feel.<ref name="five"> Recently the i-Limb hand, invented in Edinburgh, Scotland, by David Gow has become the first commercially available hand prosthesis with five individually powered digits. The hand also possesses a manually rotatable thumb which is operated passively by the user and allows the hand to grip in precision, power and key grip modes.
[http://www.sigmorobot.com/technology/news/boston_digital_arm.htm "Advanced Signal Processing Dramatically Improves Capability of Artificial Limbs"], SIGMO Technology, 2005. Retrieved 11 February 2007. </ref>
Recently the i-Limb hand, invented in Edinburgh, Scotland, by David Gow has become the first commercially available hand prosthesis with five individually powered digits. The hand also possesses a manually rotatable thumb which is operated passively by the user and allows the hand to grip in precision, power and key grip modes. Raymond Edwards, [[Limbless Association]] Acting CEO, is the first amputee to be fitted with the i-LIMB by the National Health Service in the UK.<ref>http://news.bbc.co.uk/1/hi/sci/tech/7443866.stm</ref> The hand, manufactured by [http://www.touchbionics.com/professionals.php?section=5 "Touch Bionics"] of Scotland, went on sale on 18th July 2007 in Britain for £8,500 (U.S. $17,454)<ref>http://news.nationalgeographic.com/news/2007/07/070719-bionic-hand.html</ref>.
Targeted muscle reinnervation (TMR) is a technique in which [[motor nerve]]s which previously controlled [[muscle]]s on an amputated limb are [[surgery|surgically]] rerouted such that they reinnervate a small region of a large, intact muscle, such as the [[pectoralis major]]. As a result, when a patient thinks about moving the thumb of his missing hand, a small area of muscle on his chest will contract instead. By placing sensors over the reinervated muscle, these contractions can be made to control movement of an appropriate part of the robotic prosthesis.<ref name="six">{{cite journal |author=Kuiken TA, Miller LA, Lipschutz RD, Lock BA, Stubblefield K, Marasco PD, Zhou P, Dumanian GA |title=Targeted reinnervation for enhanced prosthetic arm function in a woman with a proximal amputation: a case study |journal=Lancet |year=2007 |month=Feb |day=3 |volume=369 |issue=9559 |pages=371–80 |pmid=17276777 |doi=10.1016/S0140-6736(07)60193-7}}</ref>
An emerging variant of this technique is called targeted sensory reinnervation (TSR). This procedure is similar to TMR, except that [[sensory nerve]]s are surgically rerouted to [[skin]] on the chest, rather than motor nerves rerouted to muscle. The patient then feels any sensory stimulus on that area of the chest, such as pressure or temperature, as if it were occurring on the area of the amputated limb which the nerve originally innervated. In the future, artificial limbs could be built with sensors on fingertips or other important areas. When a stimulus, such as pressure or temperature, activated these sensors, an electrical signal would be sent to an actuator, which would produce a similar stimulus on the "rewired" area of chest skin. The user would then feel that stimulus as if it were occurring on an appropriate part of the artificial limb.<ref name="six"/>
Recently, robotic limbs have improved in their ability to take signals from [[Human brain|the human brain]] and translate those signals into motion in the artificial limb. [[DARPA]], the Pentagon’s research division, is working to make even more advancements in this area. Their desire is to create an artificial limb that ties directly into the [[nervous system]].<ref name="seven">[http://www.defensetech.org/archives/001478.html "Replacement Arm, Good as New"], DefenseTech.org, 11 April 2005. Retrieved 11 February 2007.</ref>
===Direct Bone Attachment===
Direct bone attachment is a new method of attaching the artificial limb to the body. The stump and socket method can cause significant pain in the amputee which is why the direct bone attachment has been explored extensively. The method works by inserting a titanium bolt into the bone at the end of the stump. After several months the [[osseointegration|bone attaches itself]] to the titanium bolt and an abutment is attached to the titanium bolt. The abutment extends out of the stump and the artificial limb is then attached to the abutment. Some of the benefits of this method include:
*Better muscle control of the prosthetic.
*The ability to wear the prosthetic for an extended period of time; with the stump and socket method this is not possible.
*The ability for transfemoral amputees to drive a car.
The main disadvantage of this method is that amputees with the direct bone attachment cannot have large impacts on the limb, such as those experienced during jogging, because of the potential for the bone to break.<ref name="four">[http://www.abc.net.au/science/slab/leg/default.htm Getting an artificial leg up - Cathy Johnson<!-- Bot generated title -->]</ref>
==Cost==
Transradial and transtibial prostheses typically cost between US $6,000 and $8,000. Transfemoral and transhumeral prosthetics cost approximately twice as much with a range of $10,000 to $15,000 and can sometimes reach costs of $35,000. The cost of an artificial limb does recur because artificial limbs are usually replaced every 3-4 years due to [[wear and tear]]. In addition, if the artificial limb has fit issues, the limb must be replaced within several months.<ref name="eight">[http://www.boston.com/business/globe/articles/2005/07/05/cost_of_prosthetics_stirs_debate/ "Cost of Prosthetics Stirs Debate"], [[The Boston Globe]], 5 July 2005. Retrieved 11 February 2007.</ref>
The i-Limb hand, manufactured by Touch Bionics of Scotland, went on sale on 18th July 2007 in Britain for £8,500 (U.S. $17,454)<ref>[8]</ref>.
''[[Jaipur leg|Jaipur Foot]]'', an artificial limb from [[Jaipur]], [[India]], costs about US$ 40.
There is currently an open Prosthetics design forum known as the "Open Prosthetics Project". The group employs collaborators and volunteers to advance Prosthetics technology while attempting to lower the costs of these necessary devices. Visit their site at http://OpenProsthetics.org.
A plan for a low-cost artificial leg, designed by Sébastien Dubois, featured at the 2007 Indernational Design Exhibition award show in Copenhagen, Denmark. It plans to be able to create an energy-return prosthetic leg for US 8 dollars, composed primarily of [[fiberglass]].<ref>[http://www.indexaward.dk/2007/default.asp?id=706&show=nomination&nominationid=163&playmovie=wmv INDEX:2007 INDEX: AWARD<!-- Bot generated title -->]</ref>
==Footnotes==
<references/>
==External links==
*[http://www.chardmuseum.co.uk/Pioneers_in_Artifical_Limbs/ Chard Museum] Display of James Gillingham's work on post WW1 artificial limbs.
*[http://www.oandpcare.org/public/glossary.asp OandPCare.org] has an extensive glossary of terms relating to artificial limbs, prostheses and the field of prosthetics
*[http://www.mtb-amputee.com/ProstheticSuppliers&Manufacturers.htm Prosthetic Suppliers and Manufacturers]
*[http://openprosthetics.org The Open Prosthetics Project]
[[Category:Medical equipment]]
[[Category:Biomedical engineering]]
[[Category:Bioengineering]]
[[Category:Disability]]
[[Category:Prosthetics]]
[[is:Gervilimur]]
[[ja:義肢]]
[[simple:Artificial limb]]
[[nl:Kunstbeen]]