A New Approach to Orthotic Management


Rehabilitation Engineering Program, University of Tennessee, Memphis, Tennessee. This article presents an orthotic management system for preschool-age myelodysplastic and similarly disabled children. As in the past, the challenge has been to mold these children physically and mentally to function in society by developing their remaining potential to the utmost. Naturally it is expected that these children will progress more quickly when interrelating with their peers as much as possible. However, their physical disability, in particular their inability to be mobile for short or long distances, is a deterrent.

At this point I do not think it is necessary to review the physiological and psychological importance of the benefits of assisted mobility for these children. Our orthotic system deals with children who have approached the sitting stage of development (approximately 8 to 12 months of age), or who should be sitting but cannot because of their neurological involvement. This system can be used throughout the preschool era ending at the approximate age of 6 years. At that time another form of orthotic management must be applied because of limitations which will become apparent later in this article.

At the Rehabilitation Engineering Program in Memphis, which is jointly administered by the Crippled Children's Hospital School and the University of Tennessee, we have undertaken a project involving preschool spina bifida patients and similarly disabled children and their parents. This project consists of a mobility system which is comprised of two main devices: a plastic upright positioner ( Figure 1 ) and a base equipped with wheels ( Figure 2 ). Both are heat formed from ABS plastic. The plastic upright positioner or PUP can be easily converted to a sitting position ( Figure 3 ) by changing the relationship of the thoracic and pelvic sections. The combined weight of these two devices is 7.25 kg, of which 2kg is the standing device. The base is equipped with a fold-out handle which is permanently attached because we know from experience that anything which is removable from a device usually becomes permanently removed. The common parental response is, "Gee, I just can't understand what could've happened to it." The handle can be folded into the base during hand propulsion by the patient in the sitting position, allowing short-distance travel (e.g., room to room), or it can be folded out in the upright wheeling position, thereby affording a greater range for transportation which is directly controlled by the parents (e.g., shopping).

The base is fabricated to accept the pelvic section of the PUP, securely retain- ing it by a spring-loaded pull-pin and hook. This total unit allows four main modes of use: crutchless standing, independent sitting ( Figure 3 ), mobility during sitting ( Figure 4 ), and mobility during standing ( Figure 5 ). Crutchless standing frees the hands and, of course, allows the child to participate in ADL activities at table level. In the sitting position the foot pods and the pelvic section produce three-point stabilization to give more support to those who require it. Mobility during sitting can be achieved by positioning the PUP on the wheeled base. By swiveling the wheels into the forward position, mobility is achieved during standing. Intermittent stopping is achieved in the upright wheeling position simply by tilting the base forward to rest on two posts permanently attached to the base. Steps no longer present the problem encountered with most four-wheeled devices, which have a large base that makes them bulky and awkward when ascending and descending stairs. Automobile transportation is simplified, since the mother simply detaches the base from the already standing PUP by use of the pull-pin, places the base in the hack of the vehicle, and positions the child beside her, seated, with a safety belt. Incorporating these capabilities through two simple devices achieves much better acceptance by the child and parent, and it no longer becomes a major operation to take the child on an outing.

The fabrication of these two devices involves vacuum forming 6-mm (`i-in.) ABS plastic over hard plaster or epoxy molds. The standing device comes in three different sizes to accommodate a large percentage of children. The wheeled base will accept all three sizes of the pelvic component. Both standing device and base can be formed from two 76 cm x 76 cm x 6 mm (30 in. x 30 in. x ‘i in.) sheets of ABS. During thermal forming, a "F' configuration on the hip section of the mold produces a receptacle which will accept the thoracic component in the two positions, sitting and standing. Similarly, tubular aluminum stock is placed on the mold to produce the foot-pod receptacles. By pretrimming and fabricating the main component parts, pelvic, thoracic, and foot pods, the patient can be measured for his device. The correct width of pelvic components actually can be selected by placing the patient supine and fitting the device directly to him. Measurements are then taken from the pelvic section to the feet and also to the thoracic section. From these measurements the aluminum bars and tubes are cut to length and permanently assembled, ready for final fitting.

A good, comprehensive physical therapy program is necessary to increase coordination of the child's remaining functional muscles and to familiarize the child with the device and its modes of use. Falling, swivel walking, swing-to walking with a walker or crutches, removing and donning his standing device-just as much as the child is capable of achieving -should he taught. This training gives the child a good, healthy attitude toward assistive devices, which he or she will inevitably have in some form as the years pass by.

A disadvantage of this system is the inability to flex the knees in the sitting position. However, children at this age and small stature will not need to bend at the knees to sit in most places. Obviously, this limitation becomes a problem for older school-age children, and something new is definitely needed. As with all rigid standing devices, there is a problem with mobility it is cumbersome. There is still a need for a walker, crutches, or some other form of supportive aid.

The foot pods can be altered by the orthotist in many ways for each child. For instance, in the initial stages of standing he may want the foot pods to be flat on the floor. Later he may wedge them to reduce friction for the ambulating child. Slight abduction of the hips increases the stability of lax hip musculature. It is also a simple matter to accommodate knee-flexion contractures and leg-length discrepancies. Children who need extra support are controlled during sitting. The device is quick and easy to put on. The thoracic section can be placed either anteriorly or posteriorly, depending on the extent and level of neurological involvement. Often a large deformity on the back will necessitate placement of the thoracic section anteriorly. One of the main advantages is the ability to fit a large percentage of these children quickly with prefabricated component plastic parts. Unfortunately, the management of these children becomes more difficult as they get older and heavier.

The next phase of the project will be concerned with the development of concepts and devices which will permit the continuing management of children as they become older and have wider-ranging rehabilitation needs.