Prosthesis_1_ by welcomegong3

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									                                 1-Prosthesis


Definition: A device used to replace an absent body part whether due to
trauma, disease or congenitally absent ones.
Prosthesis of the upper limb may be cosmetic, functional or combination
of both.


- Arm function to place hand in adequate position to fulfill a particular
task.
- Hand tasks:
        1- Manipulative tasks.
        2- express feeling.
        3- Explore environment.
- No prothesis can replace all function satisfactory. Selection is based in
specific requirement of the amputee.
Types of prosthesis & control systems:
   1- Cosmetic:
This is the simplest and lightest type available.
For transradial (forearm = below elbow) it consists of
1- Foam filled glove with                       2- Wired fingers
                     3- Fitted to a self- suspending socket.
2) No control system required
For higher levels:
1) There is a need for a prosthetic elbow joint.
2) An endoskeletal system is used that consists of:
        a) Same hand as above (attached to)
        b) Foam covered tube forearm.
        c) Upper arm section attached to the socket.
      d) socket may be:
             1- Simple figure of eight appendage for suspension.
             2- Self suspending socket.
Advantage of this prosthesis
It provides best cosmetic replacement but with minimal functional benefit
e.g.: Holding objects steady or carrying things over forearm.
N.B: Individually sculpted silicon hands are available which are
excellent cosmetically but expensive and not strong enough for any
practical daily tasks.
II) Functional U.L. Prostheses:
A) Body powered:
      This prosthesis is the simplest functional prostheses. Body
movement is harnessed to control the terminal device (and elbow). A set
of appendages harness the body movement:
Example (1) biscapular protraction, (2) shoulder flexion (and elbow
extension = in cases of transradial amputation) are used to control
terminal device.
(2) Shoulder depression, extension, internal rotation, & abduction operate
the elbow lock in trans humeral amputation.
This type of prosthesis is a working tool & it is functional rather than
attempting to be cosmetic
(B) Electric Powered:
Idea: A battery – operated motor moves the hand and/or gripper, wrist
or elbow by either.
   1- Myo-electric control.
   2- Servo control.
   3- Switch control.
Rechargeable batteries are mounted within the prosthesis and delivered
with charger.
1- Myo-electric control:
    Electrodes pick up microvolts of electricity produced by
        contractions in the muscles of the residual limb.
    Signals are amplified and thereafter they activate the motor.
    In operating hand there may be 2 electrodes; one on extensor
        muscles and one of flexor muscles groups for opening & closing
        the hand respectively.
    Alternatively a single site placement for voluntary opening &
        automatic closing can be used.
    Wrist movement can be controlled myo-electrically using 2 site
        system.
    An electric elbow lock can be activated be a single site placement.
2) Servo Mechanisms:
        The same movements used to control body powered prosthesis, can
operate an electric hand but with less shoulder girdle movement. Where
mechanical energy is transmitted into electric energy to operate the
device motor(s).
3) Switch control:
Using harness or touch pads to control electric devices in different ways.
N.B.:
Electrically powered prosthesis are not recommended for primary
amputee's because they are:
(a) Heavy                  (b) require close fitting socket.
(c) More complex to operate & care for.
They can be considered 6 months post amputation when edema has
completely resolved, and the amputee has enough experience with either
body powered or cosmetic prosthesis.
Terminal devices
   - Used to replace the task of the hand,
   - It may be cosmetic or functional / passive or active.
The most commonly used active functional device is the split hook:
    It consists of once static – one movable new.
    Grip in achieved by elasticated bands holding the two jaws
      together, and can be increased by increasing number of bands.
    The device is activated by harness attached to the lever of the
      moving jaw as residual limb moves, harness pulls the jaw open,
      providing good proprioceptive feed back.
If cosmoses are important, a cosmetic hand can be provided: (Cosmetic
hand see above).
If patient seeks combination between cosmoses and function, same device
as above is used but with mechanical hand  same shape as the human
hand and body power pulling the thumb and fingers apart. But it has some
disadvantages, as it is harder to operate than the split hook, has poorer
grip, bulky & making precision difficult. However it is helpful if an
amputee not demands high level of manipulative skill from the prosthesis.
Terminal devices with special tasks:
   - Active: pliers – tweezers (using operating cord).
   - Passive: hammer, fishing red holder tool holder.
2-Prosthetic joints:
Wrist unit:
A cylindrical wrist unit either hand or electrically operated to provide
360° rotation, allow positioning of the terminal device in adequate
supination/ pronation range for the required task. Usually wrist units have
a disconnect facility allow change of terminal device.




Elbow joint:
        Several forms of prosthetic elbow joints are in use. Hand operated
joints are commonly used with cosmetic prosthesis. In addition, body
powered elbow joints, used with body powered prostheses, are utilized.
They are operated using operating and elbow lock cords. Operating cord
operates the terminal device when the elbow is locked, while with elbow
unlocked it operates the elbow joint.
Suspension:
        For hand amputation and wrist disarticulation self suspension is
used that depends on hanging the socket to bony prominences, namely
radial and ulnar styloid processes.
        For transradial amputation when using a supra condylar socket, self
suspension is applied using medial and lateral humeral epicondyles for
hanging the prosthesis. When cup socket is utilized a simple figure of
eight appendage suspension id applied.
For transhumeral amputation appendage suspension is utilized.
N.B.:
        In case of transradial amputation cup socket is used when amputee
need carry heavy objects, with very short residual limb, or bilateral
amputation. Supracondylar socket is used with cosmetic and passive
terminal devices.
      In wrist disarticulation supination /pronation is controlled by wrist
unit or by split socket with one section at the wrist and the other at the
distal part of the arm, sparing the forearm to perform movement.




                          Lower Limb Prosthesis
Types of lower limbs prostheses :
      Types of L.L. prostheses depend on different stages after
amputation. There are three types: Immediate post- operative prosthesis,
temporary prosthesis, and definitive prosthesis.


I- Immediate post- operative prosthesis
- Used for young patients, usually after a traumatic injury.
- Consists of rigid dressing (formed of plaster or fiber glass padded with
felt, cotton, or poly urethane), pylon, and foot.
- Pylon is usually made of aluminum, steel or plastic.
- It helps patient to gain psychological support, early walking (with
assitive device 5-12 days post operative) leads to less hospital stay, and
reduce phantom pain.
Disadvantages are the possibility of impaired healing & falls due to early
ambulation.
Contraindication:
   1- History of slow wounds healing.
   2- Extreme obesity.
   3- Excessive preoperative edema.
   4- Lack of 45 days preoperative ambulation.
II – Temporary prostheses:
    It is usually used for 3 to 6 month after amputation.
    It helps early weight bearing, and reduces edema in the residual
      limb stamp.
    The most common type of temporary prosthesis is adjustable
      prosthesis. It consists of a socket, pylon, foot. It can be modified so
      that the foot in moved in medial, lateral, anterior, posterior
      inversion, eversion direction. These adjustments help to correct
      gait deviations, increase energy efficiency, and make walking more
      efficient and cosmetic. Therefore it is used in early stages of gait
      training.
    Temporary prosthesis can be converted to definitive or final
      prosthesis with cosmetic modifications.
IV- Definitive prosthesis
    It is used when limb volume becomes stable.
    It can be applied 3-9 months postoperative.
    Life span 3-5 years.
    Changes are needed when there is
   1- Residual limb atrophy.
   2- Weight gain or loss.
   3- Excessive wear after prosthesis.


                       Designs of L.L. Prostheses
     Endoskeletal (Modular)                         Ex oskeletal
IPOP, temporary, or definitive         Defenitive only used in occupations
                                       that need high durability or dealing
                                       with heat.
                              Components
   1- Socket                          Hard outer cover made of plastic
   2- Pylon made of steel,           laminate.
      aluminum, titanium or           Socket is sculpted or built in.
      carbon (carbon is used with
      flex foot).
   3- Prosthetic foot.
   4- Shock absorbing unit
      bumpers, or springs or fluid
      full) attached socket (above)
      or foot (below)
   5- Finishing : soft foam, or
      prosthetic skin


 3-Prosthetic foot:
It should be:
   1- Providing stable base of support.
   2- Shock ubsorption.
   3- Joint & musch stimulation.
   4- Cosmetic appearance.
Conventional:
1) Articulated:
Single axis:
Have a single metal axis that allows plantar (15 degree) and dorsiflexion (
5-7 degree). Internal keel surrounded by foam-rubber outer lining.
Loaded with dorsiflexion bumper that replaces eccentric contraction of
plantar flexors, and plantarflexion bumper that replaces eccentric
contraction of dorsiflexion. It allows level- floor ambulation but does not
allow for walking on a steep incline.
Multiple- axis foot:
      The multiple axis foot has two joints, a rubber rocker block that
allows dorsiflexion and plantarflexion and a transverse ankle joint that
allows rotation, eversion and inversion. It contains a wood keel and outer
cover of foam rubber. It allows walking on level ground and inclines
II) Non articulated
The solid-Ankle Cushion-Heel
      Consists of wood keel that extends forwards to the toe break and is
surrounded by molded foam. The SACH compressible rubber heel
simulates plantar flexion. At loading response the heel wedge comprises
to simulate plantar flexion.

Stationary- Attachment Flexible Endoskeletal (SAFE) FOOT
      The SAFE foot keel, is composed of rigid polyurethane plate at an
angle 45 in the sagittal plane to provide eversion and inversion. To elastic
bands extend on the plantar surface that courses the keel to dorsiflex from
mid- to terminal stance. At pre swing the keel releases.

Stored Energy (STEN) Foot
      The keel is subdivided into comprisable and non compressible
segments, a structure that allows energy storage from loading response to
mid swing and release it at push off.
Dynamic Response Feet
                                                               Articulated

College Park True Step Foot
      It has three axes one vertical and two transverse axes. These axes
allow mobility in the three planes of motion. Two bumpers, dorsi- and
plantar flexion bumpers are included. In front there are two split toes of
carbon fibers.
Non- Articulated
Long keel:

Flex foot:
      Two elastic carbon fibers attached to a horizontal carbon foot plate.
Carbon fibers extend to include the pylon.
Springlite
     Similar to flex foot, but consists of one elastic carbon fibers and
one fiber glass filaments surrounded by a soft cover. It is 30% less
expensive than flex foot.
Short Keel

Carbon Copy II
Consists of two carbon fiber deflection plates that return energy during
walking and running. It has a strong keel covered by polyurethane foam.
Seattle Foot
      Has a lifelike appearance. Keel stores energy in mid- to terminal
stance, and it is released at the end of the stance phase.

Sockets
PTB: areas of wt. bearing
   1- Patellar tendon.
   2- Medial flow of medial tibial condyle and antero medial shaft of
      residual tibia.
   3- Mid shaft fibula.
   4- Distal end bearing if tolerated.
Non-weight bearing
   1- Back & distal end fibula
   2- Anterior lateral edges of lateral tibia
   3- Anterior and distal tibial surface.
   4- Tibial tuberosity.
Total surface bearing
Complete weight bearing evenly distributing pressure on the contact
surface.
Depends on:
      Patient skin condition, and residual limb condition.


Suspension:
   1- Supra condylar (medial wedge).
   2- Supra condylar- supra patellar system.
   3- Supra condylar cuff.
   4- Thigh corset.
   5- Waist belt.
   6- Sleeve. (neoprene – wrethane – silic).
   7- Shuttle – pin.
                         Spinal Supports And Braces
      This group of braces can be simply classified into cervical and
trunk supports.
                             I. Trunk Supports
      This is further classified into supportive and corrective spinal
orthoses. Supportive spinal orthoses are either made of soft fabrics and
rigid spinal orthoses.


I) Supportive Spinal Orthoses
A) Soft Supportive Spinal Orthoses:
   1) Elasticon Garment:
   Elasticon garment consists of a cylinder of two-way stretch materials
that extends from the nipple lines to the greater trochanter. Stretch
material is longer anterior than posterior. Two shoulder straps used to
control downwards slide of the garment and adjust its size to subject’s
size. Two thigh pieces that prevents garment to roll up, they extend mid
way between hip and knee joints. Two spiroflex malleable metal bars
extend paraspinally.
     It is helpful in:
         Acute, subacute, and chronic low back strain.
         Advanced lumbar spondylosis.
         Discogenic lesions.
         Post operative disc conditions.
      Elasticon garment has the advantage of reducing lumbar pain while
preserving back mobility.


2) Spinal Belts And Corsets:
        These forms of spinal supports are the most commonly prescribed
types of spinal orthoses. They are usually made of leather or cotton
fabrics of different types (coutil, jean, or canavas). They are reinforced as
necessary with metal strips.
        They are classified according to their size into sacroiliac orthoses
(5-15 cm). A lumbo-sacral orthoses extend to the thoracolumbar junction
(20-40cm in height). Thoracolumbar belts extends to the inferior angle of
the scapula with height of more than 40 cm.
        Belts encircle the pelvis, abdomen, and/or lower chest according to
 its type. Buckles or laces tighten it anteriorly. A fulcrum strap is used to
 fasten and reinforce the belt. This strap passes laterally between iliac
 crest and greater trochanter.
        These forms of supports are utilized in different painful conditions
of the spine.


B) Rigid Supportive Spinal Orthoses:
1)      Chair back supports
     It is made of slightly malleable metal, covered by leather or similar
synthetic materials, fastened by buckles in front. The upper part of the
lumbar spine is more completely immobilized than the lower.
It is utilized in cases of severe painful or infectious disorders of the spine
where strong support and relative immobility of the trunk. It is used 4-6
month post operatively following spinal fusion.


2)      The light cast jacket spica
        This is made of light cast bandage. It encircles the chest and
abdomen from the nipple line to the groin. One hip and one thigh are
incorporated as far as the knee.
        This type of support is employed after all lumbar or lumbosacral
spinal fusion operations and is worn for 3 months to produce the highest
possible rate of fusion by almost complete immobilization.
II) Corrective Spinal Orthoses
1) Milwaukee brace
        Milwaukee brace is an active corrective spinal orthosis, used in
treatment of spinal orthosis, to prevent or postpone the need of operation.
Also, it can be used post operatively. In addition it can be used in the
management of ankylosing spondylitis, tuberclosis, or other infections of
the upper thoracic region of the spine.
        It consists of leather pelvic corset that fits firmly around the pelvis.
Metal sidebars are attached to the leather pelvic corset. Two posterior and
one anterior upright extend from the center of these metal sidebars to a
metal neck ring that takes 20 degree inclination anteriorly to avoid
pressure on the throat. In addition the throat has a throat mould anteriorly.
There are two occipital pads that supports the head posteriorly.
        Rib rotation is corrected by a pressure pad located over the rib
prominence. The pressure pad is fixed to a single, broad leather strap.
2)Boston brace
      it is also utilized to treat lumbar and thoracolumbar scoliosis with
apex of the curve below thoracic vertebra number 8. It is prefabricated
from polypropelene (3mm thickness) and padded with foam (7mm
thickness). It is a positive mould of normal torso, which is provided in 20
different sizes to be suitable for almost all scoliosis patients.
                       I. Neck Collars & Supports
1) Temporary Collar
      A double thickness of sponge rubber or felt wrapped round the
neck and enclosed within a length of tubegauz which facilitates typing.
Usually sponge rubber is supplied in form of sheets (20X 40 cm). It is
convenient to fold the sheets and then to trim the margins to form a chin
cut out and two shoulder cut outs in upper and lower margins
respectively.

2) Inflatable Rubber Collar
       It consists of 3 compartments, which can be inflated by a common

air inlet to any desired tension. These compartments are joined by a strip
of rubber, and a flange at either extremity carries laces to adjust
circumference.
      It provides a good degree of support without skin traumas.
However, its major disadvantage is lack of ventilation.

3) Sponge Rubber Collar
      A sheet of sponge rubber specially shaped to avoid pressure under
the clavicles and the end of the chin is enclosed within an envelope of
leather. This provides firmer support than an inflatable collars but again
suffers from lack of ventilation.


4) Thomas Collar
      Made of a thermo- plastic material and padded with sponge rubber
at the upper and lower margins to avoid undue pressure on the jaw and
clavicles. Ventilation holes can be cut in the body of the material.

5) Victoria Collar
      Two strips of spring steel form seven eighths of a circle; these are
suitably padded and connected together by three distance pieces, one in
the center of the curve and one at each extremity. Height of distance
pieces is adjustable to individual neck height.

6) Frame Collar
      In cases where pressure on the neck skin cannot be tolerated, or if
there is neck injuries of wounds that need be supervised, frame collar can
be used. Two shoulder strips of metal are curved around the shoulder.
These two strips are joined together anteriorly and posteriorly at a
triangular mild steel. From the posterior triangle a malleable steel upright
arises from the posterior triangle and end up at an occiptal strip. Another
vertical upright of malleable steel and end up by a chin cup.

7) Doll’s Collar
      This consists of two sheets of thermoplastic material made to a
plaster cast of the upper thorax, neck and lower part of the head. A light
plaster must be applied first, split down either side, removed from the
patient, reassembled and used as a negative for a plaster positive, and the
thermoplastic material must be molded to this. It is then split down each
later margin and suitably padded, the two halves being connected by
leather strips and buckles.

								
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