Ronald
Garcia, MD
Home PM&R Links Topics in PM&R PM&R Key Reference Articles
Motorized
Wheelchairs and Scooters
A.
Importance
and prevalence of wheelchair use
1.
In 1992,
there were 1,072,000 wheelchair users in the US (4.2 per 1000 population)
2.
75% of
wheelchairs are manually propelled.
B.
Safety
1.
Long-term
use of wheelchairs can result in chronic or repetitive stresses- for instance,
on shoulders, peripheral nerves, and skin.
2.
Each year
there are 50 wheelchair-related deaths and over 36,000 wheelchair related
injuries that lead to emergency room visit. About 75% of deaths and injuries
occur because the user tips over or fall from their chair.
C.
Purposes of
wheelchair and seating prescription
1.
Maximization
of efficient and independent mobility.
2.
Prevention/minimization
of deformity or injury
3.
Maximization
of independent functioning.
4.
Projection
of healthy, vital, attractive "body image".
5.
Minimization of short-term and long-term equipment
cost.
D.
General
Considerations in Wheelchair Selection
1.
Diagnosis
2.
Clinical
picture
3.
Living
situation
4.
Family
involvement
5.
Funding
6.
Previous
experience of patient/caregiver with wheelchair
E.
Energy
Considerations in Wheelchair Use
1.
Energy
consumption of wheelchair use is lowest on flat, hard surface. Carpeting, rough
terrain and even small inclines or slopes greatly increase the energy cost of
mobility.
2.
Lightweight
chairs require less energy to propel.
3.
Narrower
tires/casters have less rolling resistance on flat, hard surface but requires
much more force through uneven surfaces and are not suited for outdoor use.
F.
Basic types
of wheelchairs and their characteristics
1.
Rigid
frame- Nonfolding; commonly used in institutions; used in sports chairs
2.
X-frame-
Common folding wheelchair
3.
User-propelled-
User propels chair
4.
Assistant
propelled- Assistant pushes chair, usually large wheels are placed forward (or
has 4 small wheels); commonly used in institutions.
5.
Motorized-
Various types of battery-powered scooters or chairs available
6.
Standard
weight- Usual configuration
7.
Ultra-lightweight-
For specially active individuals
8.
Sports
chair- For specific events
9.
Adult
chair- Usual configuration
10. Pediatric chair- Various sizes available
11. Standing frame- Allows user to gain
height; motorized and non-motorized units available
12. Non-reclining- Usual configuration
13. Reclining- Useful in patients with
hypotension and for pressure relief, though some units increase shear forces on
sacrum
14. Non-tilting- usual configuration
15. Tilting- Useful in high-tone patients,
for pressure relief, for pulmonary posture changes.
II.
Manual
Wheelchair and Components
A.
Indications
1.
Physical
limitations not compatible with ambulation
2.
Need for
increased independence at work and school
3.
Poor
endurance/distance walking
B.
Frames
1.
Rigid- More
stable and energy efficient; difficult to transport
2.
Folding-type-
compact transport; heavier, more energy use
C.
Wheels and
Tires
1.
Types of
wheels
a.
Mag wheel-
durable, low maintenance; heavier
b.
Spoked
wheel- lighter; greater maintenance, less durable
2.
Types of
tires
a.
Hard rubber
b.
Pneumatic
c.
Pneumatic
with flat-free inserts
3.
Wheel/Axle
positioning
a.
Up and down
adjustments- vary height of chair; raising axle lowers seat height and rear
stability, raises forward stability, tilts the wheelchair backward, and causes
a cambered wheel to toe out.
b.
Forward and
back wheel/axle adjustments- Alter the stability of the chair
i.
Forward
adjustment- chair will tip more easily backward; desirable for paraplegics who
do "wheelies" to negotiate curbs; undesirable for bilateral lower
limb amputees.
ii.
Back
adjustment- raises rear stability, decreases ease of doing wheelies, lengthens
wheelbase, and increases rolling resistance and downhill-turning tendency.
4.
Camber- the
angle that results when the distance between the tops of the rear wheels is
less than the distance between the bottoms.
a.
Provides a
natural angle for the arms to address the wheels during propulsion; increases
stability, allows for tighter turning radius.
b.
Results in
greater wear and tear on the wheels and tires and results in a wider chair.
D.
Handrims
1.
Large
diameter- easy to propel; less distance per stroke
2.
Small
diameter- greater distance per stroke; more force required
3.
Thick-
easier to grip; more weight and width
4.
Knobby-
easier to push; more weight and width
E.
Casters-
small wheels typically found on the front of the chair; smaller casters are
suited for rapid maneuverability and are often used in sports chair; larger
wheels are easier to use on rough terrain, although on smooth, level surfaces
they increase rolling resistance.
F.
Seats and Back- standard is sling upholstery
or hammock-style which provide little support; solid seat usually placed on top
to increase support. Adding a seat cushion will raise seat height.
1.
Seat
cushion
a.
Foam- good
stability, low cost; pressure relief not optimal
b.
Coated,
contoured foam- excellent stability, cleanability, durability; expensive, can
cause heat build-up.
c.
Gel-filled-
good pressure relief, cleanability, and heat dissipation; expensive
d.
Contoured
foam with gel insert- good pressure relief, stability, cleanability,
durability; expensive, heat build-up
e.
Air-filled
villous- excellent pressure relief, cleanability, heat dissipation; expensive
suboptimal seating stability.
f.
Others-
anterior wedge and slight pommel between the thighs useful in spasticity;
lateral supports useful for flaccidity.
2.
Reclining
back- indicated for patients prone to pressure ulcers and orthostatic
hypotension; simple reclining chairs may create shear stress over the back and
sacrum during position changes; add width, weight and bulk to chair and can
make transport difficult. Backrests are commonly tilted back about 8˚ from
vertical.
3.
Tilt-in-space
seats- entire seat and back are tilted posteriorly as a single unit; also
indicated for patients prone to pressure ulcers and orthostatic hypotension;
advantage is this does not create shear stress during movement; also
advantageous for patients with tone or spasticity problems.
4.
Backrest
Height- upper border should be at least 1-2" lower than the inferior angle
of the scapula for users who propel their own wheelchair. Lower backrest permits
greater freedom of upper body and trunk movement. Higher backrest provides more
support and more area for pressure distribution.
5.
Seat depth-
if too short and thighs are unsupported, the area over which forces are
distributed is reduced, thus increasing pressure; if too long, can cause
pressure sores in the popliteal space or the patient may be forced to scoot
forward in a slumped position.
6.
Seat plane
angle- angle of the seat relative to the horizontal (Usually 1-4˚ higher
in front); increasing this may help reduce spasticity and tendency to slide
forward on the seat or lumbar lordosis but may make transfers out of the chair
more difficult and put more pressure on the ischial tuberosities.
G.
Footrests/Legrests-
help provide balance and afford protection to wheelchair user
1.
Fixed and
swing-away footrests
2.
Elevating
footrests- available for situations in which the knee cannot and should not be
flexed; also used to help minimize dependent edema.
H.
Armrest/Laptrays-
helps provide stability and balance by allowing the user to rest the elbows;
also provide point of push-off for weight shifting and pressure relief.
1.
Fixed-
inexpensive, cannot be lost
2.
Removable-
makes transfer easier
3.
Wraparound-
reduces the width of the wheelchair
4.
Desk
Length- allows the user to slide the knees under a desk
5.
Trough
style- holds forearm in place; useful for tetraplegics
6.
Swing-away/flip-up-
makes transfer easier.
7.
Laptrays-
provides larger surface to rest arm and may help prevent pain of shoulder
subluxation
I.
Brakes-
devices that put pressure on the larger wheels to lock them in position
1.
push-to-lock
2.
pull-to-lock
3.
low
mounting- does not interfere with transfer
J.
Grade aids-
"hill holders"; prevent the chair from rolling backward but do not
interfere with forward motion.
K.
Anti-tippers-
useful for patients at risk of falling backward in the wheelchair
L.
Method of
Propulsion
1.
Bimanual
2.
1-arm drive
3.
1 hand, 1
foot
4.
Bipedal
5.
Dependent
III.
Motorized
Wheelchairs and Scooters
A.
Indications
1.
Physical limitation
not compatible with manual wheelchair mobility
2.
Need for
increased independence level at school and work
3.
To improve
self esteem
4.
To increase
efficiency of mobility
5.
To spare
the upper limb joints from premature deterioration
B.
Potential
Disadvantages
1.
Relatively
high cost
2.
Weight
3.
Transportation
difficulty
4.
Maintenance
5.
Technological
dependence
6.
Limited
environmental accessibility
7.
Lack of
physical exercise
C.
General
Considerations for Powered Mobility
1.
Physical
ability
2.
Intelligence
level
3.
Age
4.
Judgment
5.
Perception
6.
Transportability
of device
7.
Reimbursement
8.
Follow-up
availability/maintenance
9.
Family
acceptance
D.
Types
1.
Direct-drive
motorized wheelchair- commonly referred to as "power base chair";
durable and suited for rough terrain
2.
Belt-driven
motorized wheelchair- more stable than direct drive wheelchairs and capable of
attaining greater speed and are more versatile; less durable.
3.
Add-on
power packs- converts manual chair to a motorized chair.
4.
Motorized
scooter- optimally used by a person who can ambulate, transfer and perform most
activities of daily living but who lack the endurance to ambulate for long
distances or to use a manual wheelchair, must avoid overuse of their limbs,
have severe RA, DJD or cardiac disease, MS, motor neuron disease or NMJ
diseases.
E.
Control
Systems
1.
Proportional
or graded response
2.
Non-proportional
(on/off)
IV.
Sizing the
Wheelchair- standard measurements listed below
A.
Seat Width-
1 inch wider than the width of the widest part of the buttocks
B.
Seat
Height- 2 inch higher than the distance from the bottom of the heel to the
popliteal fossa.
C.
Seat Depth-
1 to 2 inches shorter than the distance from the popliteal area to the back of
the buttocks.
D.
Back
Height- 2 inch less than the distance of the bottom of the scapula to the
sitting surface
E.
Armrest
Height- distance form the bottom of the buttocks to the elbow
A.
Seating
System
B.
Communication
System
C.
BFO's
D.
Respiratory
Equipments
E.
Feeding
Equipment
Home PM&R
Links
Topics
in PM&R
PM&R
Key Reference Articles