Prostheses

Rudimentary prostheses have been used since antiquity, to replace missing limbs, teeth, etc.; their use and sophistication has increased over time. In addition to the standard artificial limb for every-day use, many amputees or congenital patients have special limbs and devices to aid in the participation of sports and recreational activities.

A prosthesis is an artificial extension that replaces a missing body part. It is part of the field of biomechatronics, the science of fusing mechanical devices with human muscle, skeleton, and nervous systems to assist or enhance motor control lost by trauma, disease, or defect.

An artificial limb is a type of prosthesis that replaces a missing extremity, such as arms or 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.  Inside the body, artificial heart valves are in common use with artificial hearts and lungs seeing less common use but under active technology development. Other medical devices and aids that can be considered prosthetics include artificial eyes, palatal obturator, gastric bands, and dentures.

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. With advances in modern technology, cosmesis, the creation of life-like limbs made from silicone or PVC, has been made possible. Such prosthetics, such as artificial hands, can now be made to mimic the appearance of real hands, complete with freckles, veins, hair, fingerprints and even tattoos. Cosmeses are attached to the body in any number of ways, using an adhesive, suction, form-fitting, stretchable skin, or a skin sleeve.

There are four main types of artificial limbs. These include the transtibial, transfemoral, transradial, and transhumeral prostheses. The type of prosthesis depends on what part of the limb is missing.

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 electrodes, when the muscles in the 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.

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. This is due to the complexities in movement associated with the knee. In newer and more improved designs, after employing hydraulics, carbon fibre, mechanical linkages, motors, computer microprocessors, and innovative combinations of these technologies to give more control to the user.

Other less prevalent lower extremity cases include:

1. Hip disarticulations - This usually refers to when an amputee or congenitally challenged patient has a either an amputation or anomaly at or in close proximity to the hip joint.

2. Knee disarticulations - This usually refers to an amputation through the knee dis articulating the femur from the tibia.

3. Symes - This is an ankle disarticulation while preserving the heel pad.

In the prosthetic industry a trans-tibial prosthetic leg is often referred to as a "BK" or below the knee prosthesis while the trans-femural prosthetic leg is often referred to as an "AK" or above the knee prosthesis.

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.

Further Information Regarding Prostheses

Enhancing Prosthesis of Amputated Legs
In western developed countries the rate of amputations of lower limbs is 17.1 amputations per 100,000 inhabitants - in Spain alone 5,000 such amputations are carried out each year. Currently, the number of persons with amputations of lower limbs is steadily increasing, due to the aging of the population and the increase of peripheral vascular disease.

Prosthetics Costs
How much does "an arm and a leg" really cost? A lower extremity prosthesis (leg) can range in cost from $5,000.00 to $50,000. An upper extremity device (arm) can range from $3,000.00 to $30,000. Why the difference and why not just give everyone the less expensive variation?

Middle Ear Surgery - Ossiculoplasty and Stapedioplasty with Titanium Prostheses
For many years surgical treatment was instituted in middle ear diseases primarily to restore sound conduction, to control infection and to prevent serious complications. Changes in surgical techniques now have made it possible to reconstruct the diseased hearing mechanism in most cases.

What is Prosthetic Parity?
One of the most appropriate and logical applications of legislative parity is in Heath Care, specifically health insurance coverage. Legislative parity in health care means to pass legislation that equalizes insurance benefits.

Increased Freedom for Amputees with Advances in Prosthetic Devices
Prosthetic devices with moveable joints have gone through a number of transformations. Developing from a fairly clumsy mechanical joint to ones with robotic capability, joints have gone from operating using the musculature of the affected limb to being able to directly access electrical impulses from the body of the amputee, or from a computer within the artificial limb itself.

VA Studies Advanced Prosthetic Arm
The Department of Veterans Affairs (VA) has announced a three-year study of an advanced artificial arm that easily allows those with severe limb loss to pick up a key or hold a pencil.