Custom Prosthetic Services Ltd.
   
UPPER EXTREMITY PRODUCTS


There are six basic prosthetic options to consider for the person with an upper extremity amputation:

No Prosthesis

Cosmetic Restoration

Body-Powered Prostheses

Electrically-Powered Prostheses

Hybrid Prosthesis

Activity-Specific Prostheses

Some device types may be more suitable for specific activities than others and some individuals may need several different prosthetic devices to engage in a number of different activities. At Custom Prosthetic Services we emphasize the importance of an Initial Prosthetic Assessment. Our interest is in working with our clients to determine what their functional goals are and how best to achieve them, through the use of appropriate techniques, technology and training. Experienced amputees know that if a prosthesis does not fulfill some personal requirement, it will not be worn.


No Prosthesis

Not every person with an upper extremity amputation is a candidate for a prosthesis. Physical capabilities and limitations can be a factor, as can an individual’s development of techniques to adapt to daily tasks without the use of a prosthesis. Also, earlier unsuccessful fittings, which failed to work adequately or were painful, can contribute to an individual’s decision not to use a prosthesis.

Some upper extremity amputees who have chosen not to wear prostheses in the past have found that the advanced fitting techniques and componentry now available through an experienced Prosthetist can enhance their lives. At Custom Prosthetic Services we use or resources and experience to provide our clients with a wide range of prosthetic devices and up to date technology.
Contact us to discuss your options.


Cosmetic Restoration

Cosmetic restoration, or duplication of the contralateral arm or hand, is a popular prosthetic option. A prosthesis that is similar in appearance to the portion of the limb that was lost or is missing can be fabricated and is capable of simple grasping or carrying activities. A typical passive prosthesis may have a realistic appearance but it is generally non-functional, and rarely provides the ability to grasp items.

Cosmetic restoration, particularly the outermost covering, is typically achieved using one of three materials: flexible latex, rigid PVC, or silicone. These types of prostheses are often lighter weight than other prosthetic options and require less maintenance because they have fewer moving parts than other prosthetic options.

Advantages:

  • Lightweight


  • Minimal harnessing


  • Low maintenance


  • No control cables
Disadvantage:

  • Difficult to perform activities that require bilateral grasping.
Latex Covering

This is the most common material utilized for cosmetic restorations. Latex is usually a thin material that comes in pre-made sizes called gloves to fit over most available prosthetic hands. These hands may be passive, body-powered or electrically powered. A latex glove is most often provided in a solid color that can be enhanced by custom painted details such as freckles, nails, age spots, and knuckles. Partial hand restorations can be made with this material and often utilize a zipper in the palmar surface to allow the patient to easily don and doff but still have the stability and confidence that the prosthesis is firmly attached.

The advantage to this material is that it is fairly lightweight and inexpensive. The disadvantage is that latex easily stains, often permanently. Most wearers replace a latex glove 3-12 times a year due to wear and staining. Some patients also say that it lacks the realism (aesthetic and sensory) offered by other materials.

Rigid PVC

These PVC gloves are available in a variety of colors and sizes. They are solid color core, which is advantageous because if scratched the color is retained. PVC gloves resist some chemicals but can absorb stains and require prompt cleaning if soiled, to prevent permanent marking.

Silicone

Silicone has recently been refined for utilization in upper extremity restorations. Custom silicone restorations require more complex impressions and mold-making techniques but often provide the most realistic and long-lasting restorations. Realism is achieved by the varied texture of silicone, size and shape matching through custom molding, and color duplication utilizing multiple photographs and real-time comparisons of the non-affected hand.

The final product is a cosmetic restoration that often goes unnoticed because it so closely resembles the non-affected hand. The advantages of silicone are that it does not stain like latex or PVC, provides the highest cosmetic restoration quality, and has a longevity of 3 to 5 years. One disadvantage of silicone is that it is heavier than latex and can only be used with certain types of prosthetic hands, specifically those that utilize an endoskeletal design. Silicone is also more expensive and takes longer to fabricate.

Silicone Hand Silicone Fingers
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Body-Powered Prostheses

The body-powered prosthesis is also known as the conventional prosthesis and it has been available for many years. Gross body movements, generally of the shoulders, chest and upper arm, power it. These movements are captured by a harness system, which is attached to a cable that is connected to a terminal device (hook or hand). For some levels of amputation or deficiency an elbow system can be added to provide the patient additional function. The action of the control cable crossing the elbow is often used to drive the motion of the elbow joint.

Prosthetic Arm

For a client to be able to control a body-powered prosthesis he or she must possess at least one or more of the following gross body movements:

  • Glenohumeral flexion (swing the upper arm forward)


  • Scapular abduction or adduction (spread the back out and draw it inwards)


  • Shoulder depression and elevation (move the shoulder up and down)


  • Chest expansion (lift and expand chest)
There are several basic requirements that are generally necessary for a client to be a candidate for a body powered prosthesis:

  • Sufficient residual limb length


  • Sufficient musculature


  • Sufficient range of motion
Advantages:

  • Simple design


  • Highly durable


  • Useful in wet, dirty or dusty environments


  • Positional and control awareness through proprioception (control cable force feedback)


  • Reduced maintenance cost compared to electrically driven prostheses


  • Multiple and readily-changeable terminal device options
Disadvantages:

  • Uncomfortable and restrictive control harness


  • Restricted range of motion and functional envelope (arm positions in which useful work can be done)


  • Not as cosmetic in appearance due to exposed cables and hooks, etc.
There are two types of controls for body-powered hands and hooks, voluntary opening and voluntary closing: Voluntary opening uses elastics or springs to keep the device closed and gives the client grasping control even when the client is relaxed. The tradeoff for this is limited grip force, often less than 6 pounds. Voluntary closing uses elastics or springs to keep the device open and allows the patient to have substantially greater grip force, often over 50 pounds, but does not allow the client to relax without losing grasp.

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Electrically-Powered Prostheses

Electrically powered prostheses use small electric motors to move the prosthetic components. These motors can be found in the terminal device (hand or hook), wrist, and elbow. An electrically powered prosthesis utilizes a rechargeable battery system to power the motors. Because electric motors are used to operate hand function, grip force of the hand is significantly increased, often in excess of 20-32 pounds.
Prosthetic Arm Prosthetic Arm
There are several ways to control this type of prosthesis (control schemes):

  • Myoelectric Control


  • Servo Control


  • Push Button Control


  • Harness switch Control
In most cases a single control scheme is chosen. For the more advanced/ higher-level fittings, several control schemes may be used on the same prosthesis to provide enhanced function.

Myoelectric control utilizes small electrodes resting on the surface of the skin to detect and then have amplified tiny electrical signals emanating from voluntarily controlled muscles, typically in the residual limb. These signals act as ‘switches’ to control specific functions and activities of electric motors associated with the prosthetic terminal devices, wrists, and elbows.

Advantages:

  • Relatively small muscle contractions required


  • Minimal if any harnessing


  • Enhanced cosmetic appearance with silicone or latex covering


  • Better functional control in many body positions


  • Various prosthetic suspension options
Disadvantages:

  • Batteries require charging and other maintenance


  • Higher initialcost system with more expensive repairs


  • Heavier prosthesis, requiring more effective suspension


  • Susceptible to damage in moist environment

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Hybrid Prosthesis

A hybrid prosthesis is generally fabricated for those persons with trans humeral (above elbow) amputations. It is comprised of an electrically powered component (hook/hand, wrist or elbow) together with a body-powered component (hook/hand, wrist or elbow).

Hybrid Prosthetic Arm

Advantages:

  • Weighs less and costs less than prosthesis with electrically powered elbow and hand


  • Ability to simultaneously flex the elbow and operate the wrist or hand
Disadvantage:

  • Similar to respective electrically powered and body powered prostheses

Activity-Specific Prostheses

Some activities require a purpose-built prosthesis due to limitations in performance or susceptibility to damage of other types of prostheses.
Golf Basketball
These types of prostheses are often for recreational purposes and can encompass activities as diverse as music, water-skiing, cycling, fishing, weightlifting, and gymnastics. The only real disadvantage to this prosthetic option is that its specificity limits what other activities can be performed outside of its intended use.


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