Chris needed a seating system that managed his
spasticity, to enable him to achieve his potential
for switch access.
By Michelle L. Lange, O.T.R., Chery 1 McDonald, P.T.,
and Joe Marcoux
hristopher Rakestraw is a
very interactive, social 16year-old who has spastic
quadriparetic cerebral palsy
with mixed athetosis. A
high school junior mainstreamed in a regular class,
he communicates only by eye gaze.
This often results in others underestimating him, although his cognitive
level has been tested at above average.
Chris has high muscle tone throughout, which mainly manifests itself in
patterns of extension and adduction.
His movements are generally uncontrolled or random, or limited to stereotypical reflex patterns, such as an
asymmetrical tonic neck reflex to either
side. His vision and hearing are normal,
but he is dependent for all of his selfcare, transfers, mobility and communication needs. He very much wishes to
be more independent.
In February 1994, Chris was
referred to the Assistive Technology
Clinics (ATC) at The Children’s
Hospital in Denver for assessment in
the areas of switch access, powered
mobility, communication, computer
use and environmental controls. The
ATC Team is comprised of rehabilitation physicians, physical therapists, an
occupational therapist, a rehabilitation
engineer, speech pathologists and a
learning specialist.
When Chris first came to the ATC,
he had no means of independent mobility and no successful switch access. He
was seated in an Invacare Ride-Lite
5000 manual chair and a linear seating
system with an antithrust seat, lateral
chest supports and hip guides. The
ATC team decided to begin by determining an appropriate seating system
for Chris, as the foundation for access
to other technologies.
During a routine visit to the
Rehabilitation Clinic, Chris was
referred to the hospital’s Seating and
Mobility Clinic, as he was obviously
outgrowing his linear seating system.
Due to his significant collapse into posterior pelvic tilt with accompanying
kyphosis- which had never been man-
Photos by Diane Huntress
22
TeamRehab Report
A Custom Fit
Chris is receiving
ongoing diagnostic
therapy to work on
access to a computer
and the DynaVox
communication device.
ed to facilitate distal control for
access. An SSO is often recommended
for clients with orthopedic deficits,
such as scoliosis or a dislocated hip.
Chris’s spine is straight when his
pelvis is positioned correctly and he
has at least 90 degrees of flexion at his
hips and knees, so he required little in
the way of drastic contours in an SSO.
However, he did require secure, total
body support to help manage his muscle tone and extraneous movement.
After discussing these factors with the
family, the team decided an SSO
would best meet Chris’s seating needs.
An SSO is fabricated by placing
the client on a prone form, which is
usually tilted so that the head is lower
than the hips. A space in the form
allows the head to hang down so that
the cervical area is neutral and a shelf
aged well in previous linear systems-a customized,
supports the knees for adjustment of the pelvic posicontoured seating system, the Sitting Support Orthosis
tion, as possible.
(SSO), was recommended.
A bag of polystyrene beads is placed on top of the
An SSO is a custom-molded plastic shell, mounted
client and all of the air is then evacuated. This form is
filled with plaster, creating a positive of the client’s
on a block of foam. The first SSO was fabricated nearly 20 years ago; today, these
pelvis and back. The hardened
seating systems are made by Chris required secure, total positive is corrected, as needed,
specialists in several cities
and the resulting plastic shell is
body support to help
throughout the United States.
vacuum-formed and mounted on
a foam base. The plastic shell is
Chris' SSO was to be made by
manage his muscle tone
Joe Bieganek, an orthotist and
then modified for the client to
extraneous movement.
create an intimate fit with the
seating specialist at Rehab
Designs of Colorado (RDC), a
body, providing adequate suprehab technology supplier. From this point on, all four
port, optimal positioning and maximum comfort. This
groups-the seating clinic, the ATC, RDC and Chris’
shell can also be vented to allow for air flow.
family-would be working together as a team to
The SSO is lightweight (between five and six pounds)
and one complete unit, allowing it to be easily removed
design an appropriate seating system to help Chris
meet the following functional goals: independent
from a wheelchair and placed on another surface such as
mobility and communication, computer access to
the floor or a dining room chair. Head supports, lateral
allow written output for school and other needs, and
supports or other components may be incorporated into
independent control over his environment.
the plastic shell or attached separately as needed.
A unique and critical feature of the SSO is that the
Custom Seating
plastic shell can be modified for body changes and
When an SSO is recommended as a seating system,
growth. This is accomplished by altering the foam
several questions are considered: How successful have
padding or by actually heating the plastic shell and directother seating systems been in terms of optimal posily modifying the mold. The seat depth and back height
tioning, function and comfort? Is a more versatile,
can actually be increased by welding on plastic extenportable seat needed? Is the client still growing or
sions. A five-year survey by Gillette Children’s Hospital
expected to continue making orthopedic changes? Will
in Minnesota followed 76 children between the ages of
all the caregivers working with the client position him
three and 14 years, all of whom were fitted with SSOs.
or her correctly each time the client is seated?
The average lifetime of the SSO was 37.5 months, with a
In the past, Chris had been seated in linear seats,
range of 11 to 64 months. The survey also found that the
including antithrust seats. These had always allowed a
SSOs required an average of 6.5 hours labor for growth
significant amount of posterior pelvic tilt and did not
adjustment during the lifetime of the seat. (1)
adequately provide the proximal stability that he needHowever, there are some drawbacks to the SSO. It is
and
24 TeamRehab Report
An SSO is fabricated by
placing the client on a prone
form, placing a bag of
polystyrene beads on top and
then evacuating all the air.
Chris in his previous linear,
antithrust seat. Linear
systems were never able to
manage his significant
collapse into posterior pelvic
tilt and accompanying
kyphosis.
costly, particularly when compared with linear seating
systems that are about half the price, or even traditional
molded seats. In addition, making an SSO is a labor-intenChris’s hips still tend to adduct, but all hip abductors he
sive process. The client must be placed correctly into the
has tried in the past have led to skin breakdown.
SSO or else the contours will not lit correctly.
Chris has started using switches to access technoloWeighing all these factors, the team decided that the
gy, although his switch control remains very difficult
SSO would still best meet Chris’ needs. The physician
and tends to fluctuate. He shows good potential for using
wrote a letter of medical necessity and RDC submitted it
the right side of his head, his lateral right forearm, and
to the Colorado Handicapped Children’s Program, which
his lateral right knee for switch access. He is receiving
then funded the seating system at a
ongoing diagnostic therapy to
cost of $3,500.
A unique and critical feature
work on access to a computer
In addition to a new seating sysand the DynaVox communicatem, Chris needed a new manual of the SSO is that the plastic tion device from Sentient
wheelchair. The seating clinic team
believed the tilt-in-space feature of shell can be modified for body sys~~~e Chris could operate a
the Quickie TS would help manage
power wheelchair with single
changes and growth.
Chris’s position by improving his
switch scanning, this is a very
comfort, relieving pressure under his bony pelvis and
tedious and slow method. After discussion with Chris
decreasing fatigue. The Handicapped Children’s Program
and his mother, we decided to instead wait and develop
also funded the chair, which cost $1,800.
three switch sites (which he shows good potential to be
able to use) for forward, left and right directional conPositive Results
trol. And as his use of the DynaVox improves, we will
Chris received the SSO and the Quickie TS in May
most likely recommend environmental control through
1994. Once he was positioned in his SSO, optimal
this device.
alignment was achieved and he demonstrated improved
Meanwhile, Chris’ school is also pleased with his
comfort, fewer total extensor patterns, less extraneous
new system and notes that he eats better. He continues to
movement, more proximal stability and improved
communicate by eye gaze in class, but we anticipate this
motor control.
will soon change when he obtains a DynaVox. In addiChris’ mother states that although the SSO is bigger
tion, his overall independence at school will improve
(due to Chris’ growth) than his previous seating systems,
greatly as his access to technology expands.
m
it is easier to transport because it is so lightweight and all
Footnote:
one piece. Since the plastic shell is well-padded, she
1 Carlson, Marty and French, John Growth Accommodation Study,
believes Chris is more comfortable and relaxed. And
Gillette Children’s Hospital of Mmnesota., 1980-1985.
being more relaxed, she notes, allows him to open his
Michelle L. Lange, O.T.R., has worked at The Children’s
mouth easier for improved eating.
Hospital Assistive Technology Clinics for five years, She evaluAesthetically, too, the SSO has proved a good choice.
ates children and adults with a variety of disabilities for access
The seat is a thin shell conformed to Chris’ body, so that to technology. Cheryl McDonald, P.T., has worked at The
Children’s Hospital for six years, jive of them at the ATC. Her
when he is seated very little of the SSO is visible. As a
area of expertise is seating and mobility.
result, people tend to see him and the seat “disappears.”
The Children’s Hospital, ATC, 1056 E. 19th Avenue,
Denver, CO 80218; 303/861-6250; fax: 303/861-6066,
Finally, Chris now exhibits increased sitting tolerance,
which his team members and family attribute to both the
Joe Marcoax has worked at Rehab Designs of Colorado for
SSO and the tilt feature of the Quickie TS.
more than four years in the areas of seating, mobility and rehaIn the time that Chris has had his new wheelchair
bilitation equipment.
Rehab Designs of Colorado, 5855 Stapleton Drive North Unit
and seating system, some adjustments have been made,
A150, Denver, CO 80216: 303/322-6544; fax: 303/322-6630.
such as placing additional padding under the pelvis.
2 6 TeamRehab Report