Amputations and Prosthetics

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Common Causes:

1. Congenital deformity
   1. Happens prior to birth
   2. Person is born without the limb or with an incomplete limb.
2. Traumatic amputation
   1. Limb is severed during trauma, such as a car accident, work related accident, etc.
   2. Additional surgical amputation may be necessary depending on the amount of damage sustained to the remaining limb.
3. Surgical amputation
   1. Removal of limb determined to be necessary due to infection, cancer, or other diseases.
   2. Limb or part of limb surgically removed at an adequate distance above the diseased area.

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Types/Levels of Amputations

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Pain

Different pain syndromes can present after amputation. Each type of pain rarely exists in isolation and frequently contribute to one another.

1. Stump/Residual pain
2.  Phantom limb pain

1. Stump Pain / Residual Pain

The immediate aftermath of limb amputation in the first postoperative days is dominated by surgical wound pain. This pain is readily identifiable and confined to the surgical site. Surgical stump pain is often described as sharp, aching, and severe. Acute stump pain would be expected to resolve in the first few weeks after amputation, however, ∼10% of patients will go on to experience persistent stump pain.

Causes of persistent stump pain
• Infection
• Wound breakdown
• Arterial insufficiency
• Osteomyelitis
• Bone spur
• Hematoma
• Stump neuroma
• Poorly fitting prosthesis

Stump neuroma – cause of residual pain
A neuroma is a collection, or bundle, of nerve endings that forms under the skin of your residual limb. Neuromas take time to develop and are not usually seen in the first few weeks after amputation. Features suggestive of neuroma formation include a focal point of pain at the stump, spontaneous pain, and localized sensory changes. It can become very sensitive, especially if the tangle is pressing against your prosthesis.

2. Phantom Limb Pain

Phantom limb pain is the most widely known post-amputation pain syndrome. Phantom limb pain is typically felt in the distal extremity of the absent limb. Pain characteristics vary but are often described as being cramping, burning, or shooting in nature. It is not uncommon to observe that if a patient experiences severe pain in a limb before operation then the same pain will be experienced after removal of that limb. Phantom pains are usually episodic occurring in short bouts ranging from a few seconds to many hours. It is the minority of patients who have severe and unremitting phantom pain.

Phantom Limb Pain vs Phantom Limb Sensation

• Phantom limb pain– pain or discomfort felt to be coming from the missing limb or body part

• Phantom limb sensation – sensation or perception of movement coming from the missing limb or body part.
A phantom limb sensation is a non-painful perception of the continued presence of an amputated limb. Patients may report phenomenon from the missing limb such as tingling or itching. These non-painful phenomena are termed phantom sensations. The phantom limb may also be felt to be in a different position, shape or size to the missing limb.

Amputation Management – Pre prosthetic Phase

This phase of treatment manages the healing process of the amputated limb, prepares the limb for prosthetic use, and helps the patient adapt to physical and emotional changes.

General considerations

1. Provide the patient with emotional support.
    a. Depression due to loss of limb, decreased function, loss of work or leisure roles
    b. Phantom limb sensation/ phantom limb sensation/ residual limb pain.
2. Manage hygiene and wound healing at the amputation site.
3. Desensitize limb to touch and pressure in preparation for prosthetic use.
4. Assist to shrink and shape limb in preparation for prosthetic use.
5. Special considerations apply when fitting prostheses for children with congenital deformities – please see separate chart.

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Treatment Techniques– Pre-prosthetic Phase

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Types of Prostheses- Upper Extremity

Body Powered – Body motion is used to apply tension on the control cable to activate the terminal device and elbow unit.

 

Cosmetic or Passive – has no functional parts and is made to look like the remaining limb as much as possible, including the color.

 

 

Myoelectric– uses EMG signals to activate electric components embedded inside the prosthetic socket that are in contact with the patient’s skin. The components pick up EMG signals as the muscles contract. The signals are amplified and relayed to the electrical terminal device, wrist unit, and/or elbow unit.

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Advantages and Disadvantages of Body-Powered prosthetics:

Advantages:

• Relatively lightweight/durable
• Provides some sensory/proprioceptive feedback
• Cost effective
• Residual limb shape does not need to be definitive in size
• Hook terminal device allows easy visibility of objects
• Can be used outdoors in extreme temperatures and conditions

Disadvantages:

• Needs a harness on the body
• Axillary loop may feel uncomfortable
• Hook terminal device may generate a negative response by others
• Training is required to use terminal device in a variety of positions
• The prosthesis looks “unnatural”

Advantages and Disadvantages of Myoelectric prosthetics

Advantages

• Improved cosmesis
• Increased grip force (up to 25 lbs. in an adult myoelectric hand)
• Minimal or no harnessing
• Ability to use overhead
• Minimal effort needed to control
• Can control more closely, corresponding to human physiologic control

Disadvantages

• Cost of prosthesis $ $ $
• Frequency of maintenance and repair
• Fragile nature of glove and frequency of replacements
• Lack of sensory feedback
• Weighs more than body-powered prosthesis thus requiring greater strength & endurance
• Slowness in responsiveness of electric hand

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Components of Upper Extremity Prostheses

 

Sockets – used to attach the prosthesis to the residual limb	Units – the body of the prosthesis	Terminal Devices – the device used to grasp and hold objects	Control Options – the way the prosthesis is operated
1. Upper arm socket – encases and supports the residual limb. May have a harness or may be self supporting. 2. Forearm socket – encases and supports the residual limb. May have a harness or be self supporting. Design varies depending on the length of the residual limb...	1. Shoulder unit – places and positions an entire prosthetic arm. 2. Elbow unit and hinge – connects the socket to the upper arm with a triceps pad. Hinge is either flexible or rigid. May have an internal or external locking mechanism for positioning of the elbow. 3. Wrist unit – attaches the terminal device to the forearm socket. Designs vary. Can be pre-positioned...	1. Hook – more functional than a hand, less cosmetic. Provides better precision for small objects, better visual feedback, easier to maintain, weights less and costs less. -Voluntary opening hook – hook remains closed by a rubber band until tension on the cable causes the hook to open. Tension on the cable is created by body movement. -Voluntary closing – hook stays open until tension on the cable causes the device to close. Tension must be maintained to hold objects.2. Hand – more cosmetic, less functional than a hook. Can be voluntary opening or voluntary closing... .. ..	1. Body powered – operated by body motion. 2. Externally powered – activated by an external power source. –microswitch – a switch mounted inside the socket and operated by stump contact or muscle activity. -myoelectric – operated by electric signals sent by muscles in the residual limb. 3. Hybrid – operated by a combination of body motion and external power. 4. Passive – cosmetic, for appearances only with no active movement. ..

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Types of Lower Extremity Prostheses

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Components of Lower Extremity Prostheses

Pylon – the structure that attaches the socket to the terminal device. It may be basic, static, or dynamic.

Sock or gel liner – Device placed over the stump to fill the space in-between the stump and the socket and insure a tight fit.

Socket – the direct connection between the residual limb and the prosthesis.

Suspension system – the mechanism used to attach the socket to the residual limb. A variety of methods may be used, including belt straps, suction, and wedges.

Terminal device – the prosthetic foot, which provides a stable, weight-bearing surface and functions as a shock absorber.

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Treatment Techniques – Prosthetic Phase

Technique	Description	Example	Photo or Video
Patient Education	The patient is educated in the following areas: -the parts and functions of his or her prosthesis -how to don and doff the prosthesis -how to care for and maintain the prosthesis -hygiene and skin care for the residual limb	An occupational therapist shows a woman with shoulder disarticulation amputation how to put on and fasten the shoulder unit for her prosthesis	Informative video explaining to patients how occupational therapists will help them select, use and care for a prosthesis.
Prosthetic Evaluation	The prosthesis is evaluated for the following: -compliance with prescription – is the prosthesis what was ordered? -comfort – observe how the prosthesis fits and check for pressure areas. -operation – make sure all components are operating correctly, including the cables and the terminal device -efficiency – check the control system efficiency, tension stability, and the ability of the terminal device to open and close with the elbow flexed in various positions.	An occupational therapist has a man with an elbow disarticulation amputation lift a 10 pound weight with his prosthesis and checks how much displacement occurs at the socket.	Sample upper extremity prosthesis check-out form.
Prosthetic Training	Therapeutic activities and activities of daily living to train the patient in the operation of the prosthesis. -helps the patient develop tolerance for wearing the prosthesis. -application of prosthetic use to ADLs and IADLs is essential.	An occupational therapist works with a child with a congenital upper extremity deformity to use his new above elbow prosthesis to pick up and place toy cars.	A four year old boy works with an occupational therapist on functional table top activities using his new myoelectric prosthesis.

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Prosthesis for Children with Congenital Deformities

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Age	Prosthetic Fitting	Terminal Device and Treatment	Example	Video
About 6 months	First fitting, when infant is able to sit independently. Fitting optional for infants with bilateral upper-limb amelia (absence of limb) or short transverse limb deficiencies (stubs). -infants without arms quickly learn to adapt using their feet. -effect of prosthetics on adapted development a consideration.	No active controls, hook or cosmetic hand as terminal device. Training provided to parents and caregivers in application and use of prosthesis during normal play as well as care for prosthesis. Infant should wear prosthesis at all times when awake except for bathing and swimming. Prosthesis removed when infant asleep.	An infant wears a below elbow prosthesis while bearing weight on the affect limb to crawl.	A family talks about their experiences with upper extremity prosthetics for their daughter, including early first fitting.
About 2 years	Active terminal device introduced when toddler reaches certain developmental milestones:1. Able to follow simple 1-2 step directions. 2. Attention span of 10+ minutes. 3. Demonstrates awareness of terminal device. 4. Holds objects in terminal device and attempts to open it with other hand. 5. Displays interest in activities that requires use of 2 hands. 6. Able to cooperate with parent or therapist.	Active terminal device, manual or myoelectric. -myoelectric preferred if funding is available. Active terminal device integrated into fine motor bilateral activities during play. Facilitation required by parents or therapist. Toddler may not cooperate with structured therapy. Alternate unstructured methods of terminal device use may be used instead.	An occupational therapist teaches a 26 month old toddler to open the terminal device on her upper extremity prosthesis to pick up a plastic toy dish while playing.	A news story tells about a toddler who receives bilateral myoelectric upper extremity prostheses.
Preschool Age (2 1/2 to 4 years)	Adjustments for growth and terminal device settings	Treatment focused on grasp, release, and prehension using terminal device.-specific tasks used to learn grasp and release motions -learned movement incorporated into spontaneous play	A four-year-old uses his terminal device to pick up and carry a toy hammer during pretend play.	A three year old boy demonstrates his new hand prosthesis, made from a 3-D printer.
4 to 5 years	Adjustments for growth and terminal device settings.	Child trained in specific self help skills necessary for school. -opening a milk carton and snack containers or packages -holding paper -opening and closing glue and other bottles -donning and doffing prosthesis without help from an adult -managing outdoor clothing and clothing fasteners	An occupational therapist teaches a four year old girl how to open her package of crackers using her functional hand and her terminal device.	A four year old boy works with an occupational therapist to learn school related tasks using his myoelectric prosthesis.
School Age – 5 years and up	Adjustments for growth, terminal device tension. Different terminal devices for different activities.	Regular therapy no longer necessary-children continue to practice skills to learn to adjust pressure on terminal device for strength of grasp Children may need periodic training for specific activities, such as sports, arts and crafts, etc.	A 7-year-old boy learns how to hold and swing a bat using his prosthesis during t-ball practice.	A girl demonstrates use of a myoelectric prosthesis during a variety of activities.