PROSTHESIS

- Sreetama Das 3rd year, BME

WHAT DOES “PROSTHESIS” MEAN?

a prosthesis (plural: prostheses; from Ancient Greek prósthesis,

"addition, application, attachment") is an artificial device that replaces a missing body part, which may be lost through trauma, disease, or congenital

conditions. 

SORTS AND TYPES

• A person's prosthesis should be designed and assembled according to the patient's appearance and functional needs.

• Craniofacial prostheses include intra-oral and extra-oral prostheses.

• Prostheses of the neck include larynx substitutes, trachea and upper esophageal replacements.

• Somato prosthesis of the torso include breast prostheses which may be either single or bilateral.

History and early layouts Pliny the Elder also recorded the tale of a Roman general, Marcus Sergius whose right hand was cut off while campaigning and had an iron hand made to hold his shield so that he could return to battle.

During the Middle Ages, prosthetic remained quite basic in form. Debilitated knights would be fitted with prosthetics so they could hold up a shield, grasp a lance or a sword, or stabilize a mounted warrior.

Technology and manufacturing• 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.

• 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.

• A myoelectric prosthesis uses electromyography signals or potentials from voluntarily contracted muscles within a person's residual limb on the surface of the skin to control the movements of the prosthesis, such as elbow flexion/extension, wrist supination/pronation (rotation) or hand opening/closing of the fingers.

• Robots can be used to generate objective measures of patient's impairment and therapy outcome, assist in diagnosis, customize therapies based on patient's motor abilities, and assure compliance with treatment regimens and maintain patient's records.

PERFORMANCE CRITERIA

Nonetheless, there are certain elements

of socket and foot mechanics that are invaluable for the athlete, and these are the focus of today’s high-tech prosthetics companies:

• Fit • Energy storage and return • Energy absorption • Ground compliance • Rotation • Weight • Suspension • Cost• Ease of use• Size availability

MATERIALS & PROCESSES USED

1) Acrylics2) Polyurethanes3) Silicone elastomers4) Room- temperature vulcanizing5) High temperature vulcanizing

Evolution of hind limb prosthesis

Artificial limbs are typically manufactured using the following steps:

• Measurement of the stump• Measurement of the body to determine the size required for the artificial

limb• Fitting of a silicone liner• Creation of a model of the liner worn over the stump• Formation of thermoplastic sheet around the model – 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

A few layouts through the eras

RENAISSANCE (14th-17th century)

Continued…

The American civil war (1850’s)

Continued…

The Victorian age ( late 1800’s-early 1900’s)

Continued…

Circa (1930’s)

Getting back to it again

HOW DO THE MYOELECTRIC PROSTHESIS WORK?

The interface

Knee prosthesis…

Total knee replacement consists of three main components: the femoral component, the tibial component, and the plastic spacer (polyethylene). 

Categorizing knee replacement components

• whether the plastic (polyethylene) is fixed securely upon the underlying tibial component or whether it allows rotation upon the tibial component

• The last category has to do with how the metal components are fixed to the underlying bone. Most replacement systems use a special type of cement called methylmethacrylate to bond the metal component to the bones..

• Another category relates to how the posterior cruciate ligament is treated during surgery. If the posterior cruciate ligament is in good condition, some surgeons will retain this ligament and use cruciate retaining (CR) components.

ProsthesisHip

DESCRIPTION

• In a total hip replacement (also called total hip arthroplasty), the damaged bone and cartilage is removed and replaced with prosthetic components.

• The damaged femoral head is removed and replaced with a metal stem that is placed into the hollow center of the femur. The femoral stem may be either cemented or "press fit" into the bone.

• A metal or ceramic ball is placed on the upper part of the stem. This ball replaces the damaged femoral head that was removed.

• The damaged cartilage surface of the socket (acetabulum) is removed and replaced with a metal socket. Screws or cement are sometimes used to hold the socket in place.

• A plastic, ceramic, or metal spacer is inserted between the new ball and the socket to allow for a smooth gliding surface.

What can you do??

With a prosthetic limb?

And here is what you can do…

Body integrity identity disorder

Body integrity identity disorder (BIID, also referred to as amputee identity disorder) is a psychological disorder in which an otherwise healthy individual feels that they are meant to be disabled.

DENTAL PROSTHESIS

A dental prosthesis is an intraoral (inside the mouth) prosthesis used to restore (reconstruct) intraoral defects such as missing teeth, missing parts of teeth, and missing soft or hard structures of the jaw and palate. Prosthodontics is the dental specialty that focuses on dental prostheses.

PROS and CONS There are two main types of prosthetic limbs: battery powered and electric limbs. The disadvantage of a battery powered limb, when compared to an electric limb, is a more mechanical appearance. Many people also find battery powered limbs harder to learn how to use since they require the input of more physical strength. Electric limbs are more costly than battery powered limbs, and they are also heavier. The repair cost is higher than for battery powered limbs.

CONTINUED…•Cochlear implants are effective at increasing a person's hearing level.•A potential advantage of a cochlear implant is that the person may be suitable for jobs that are not appropriate for deaf people.•One potential disadvantage of cochlear implants is that they don't transmit sound the same way an ear does. This means that things sound different and can be difficult to identify.•The cost of a cochlear implant is high.

CONTINUED…•The cost of the procedure(s) is probably the most common disadvantage cited by patients. •Dental Insurance is another disadvantage. Most dental insurance plans don’t cover dental implants, bone grafts, sinus lifts, etc.•Another disadvantage of dental implants is that it requires a surgery. The implant has to be placed into your bone. Surgery is not without risks.

WHY IS IT THAT ONLY HUMANS SHOULD HAVE PROSTHESES?

The future of permanent, fully integrated prosthetic limbs and bionic implants

REFERENCES:• Henry Robert Heather Bigg, Artificial Limbs and the Amputations which Afford the

Most Appropriate Stumps in Civil and Military Surgery (London, 1885)• "How artificial limb is made – Background, Raw materials, The manufacturing

process of artificial limb, Physical therapy, Quality control". Madehow.com.• Sherman, E. David (1964). "A Russian Bioelectric-Controlled Prosthesis: Report of a

Research Team from the Rehabilitation Institute of Montreal" Canadian Medical Association Journal .

• Prosthetics and Orthotics: Lower Limb and Spine - by Ron Seymour • Wikipedia• Discovery channel- “BODY BIZZARE”

THANK YOU FOR WATCHING…

That’s all…