Children with spinal cord injury require special seating considerations.

Makayla is a talkative and opinionated 8-year-old girl. Her parents and older sister are deaf and she uses sign language when she is with her family. Two years ago, she was in a motor vehicle accident and has an incomplete C5-6 injury. She is an Asia B and has a tracheostomy. She has frequent pneumonias and has trouble with swallowing thin liquids. Makayla  needed a light weight seating system for mobility that supported her anatomy, preserved her skin integrity, and allowed her to funtion.

SKIN

When considering skin integrity, we first assess the risk as minimal, moderate, or severe. Because Makayla has mobility impairment (she cannot do an effective independent weight shift) and sensory impairment, her skin risk is severe. This means we have to provide an appropriate cushion, a chair with tilt (at least 45°) and a weight-relief program. In cushions, we have to choose between fluid or solid materials, or a combination of the two. Air, flowing gel, or any medium that flows would be considered a fluid/liquid. These materials are often the best for reducing shear and peak pressures. However, by themselves, they are often unstable as a sitting support surface. Foam, nonfluid gel, plastic cells, and similar products that don’t “flow” when you cut them are solids. Solids, being the most stable material, offer the greatest pelvic stability when sitting.

There are also products that combine these two mediums. In these systems, the fluid medium is beneath the bony prominences for the purpose of shear and pressure reduction, and the solid material provides support for the femurs all the way from the trochanters to the back of the knee, encouraging both skin protection and pelvic stability. When thinking about the person who is at the highest level of risk versus the person who is at a moderate level of risk, it is critical to consider the depth of immersion that is offered for the bony prominences, such as the ischium. When one considers the height difference between the ischials and the trochanters, it becomes evident that for a mature pelvis, one would need at least a 2-inch depth of immersion to avoid bottoming out; 11¼2-inch for a child Makayla’s age.

PELVIS

The most important lesson, when considering posture is, respect the anatomy. If we were to sit with all our load on the ischials and/or sacrum, it would be uncomfortable, and it would contribute  to skin integrity issues.

When sitting, with the goal of maximizing surface-contact area and reducing the work involved, common practice is to load the femurs from the trochanters to the back of the knee, the feet, the lumbar-thoracic intersection, and the occiput area if necessary. We also need to capture the pelvis from a posterior lateral aspect if our goal is the stabilize it. This is usually done by supporting the pelvis at approximately the level of the posterior superior illiac spine.

Lastly, be careful with pelvic straps. Lots of pressure across the anterior superior illiac spine in children under 5 years of age may actually lead to deformities as the constant abnormal loading does not allow the pelvis to open (as it does in normal development), and this may contribute to hip subluxation.

By supporting, respecting, and loading the various anatomical structures, we provide stability and balance for function.

SPINE

Stack the vertebra respect the curves. All children with spinal cord injuries are at the highest level of risk for scoliosis. By supporting age-appropriate curves, we may be able to slow down or correct a flexible deformity. We used a few degrees (5°–15°) of tilt to allow the curves to be supported in a contoured system to fight gravity’s effects on the child’s spine. The key is to respect the posterior flare of the sacrum with the pelvis that can achieve a “neutral” position, support the posterior-lateral pelvic area, and load the lumbar/thoracic intersection and thoracic area. If we put a lot of contour behind the lumbar curve, we can actually push the child forward and encourage a collapsed posture.

HEAD

If head control is still a challenge in sitting after the pelvis and the spine have been supported/accommodated, load the occipital (nucal) ledge. Use a headrest that comes under the skull and supports the head against gravity. Make sure that the child can maintain an open airway (slight extension) without a lot of jaw thrust. If posterior support is not enough, using lateral supports on the jaw bone and skull can also help keep the eyes and head in good alignment without having the child work too hard against gravity. Remember that straps are for assisting gravity, not to fight gravity. Straps alone cannot hold a child’s body up against gravity. Anterior strapping can at times be necessary for feeding and other short time activities in conjunction with all of the parameters previously discussed. 

HIPS

Start with a thorough assessment. Make sure that the child is able to tolerate 90° of true hip flexion in the absence of posterior pelvic rotation. The reason this is so important is because most wheelchair seating systems come out of the box configured with a seat-to-back angle of 90°. If the client does not have that range, then the client will be forced to sit with a posterior-rotated pelvis and a compensating “collapsed posture.” By knowing this information before ordering the equipment, a seat-to-back angle other than 90° can be requested. If an antithrust shelf is being used, check that it is not so contoured that it is increasing hip flexion. If it is, then make sure that the child can actually achieve this amount of hip flexion without posterior pelvic rotation and a flattened lumbar spine.

I have often made the mistake of increasing hip flexion to decrease extension tone, only to find that the child struggles even more and my seating is even less effective. This is usually because a hip has begun migrating out of the socket (actebaulum), and the child is uncomfortable with hip flexion and scoots forward or rotates the pelvis to open the hip.

The hip does not finish forming when the child is born. The growth plate is open, and the femoral head is floating on cartilage. The femoral neck is almost straight, and there is no angle (anteversion/retroversion). The acetabulum is very shallow. It is through weight-bearing and active muscle contraction (gluteus medius is the key muscle here) that the femoral neck begins to angle and rotate and the acetabulum deepens. For a child with spinal cord injury, the bone is most likely osteopenic, and the integrity of the hip may be compromised and prone to subluxation or dislocation. The best way to maintain the structure and joint integrity, as well as bone density is to have the child participate in an electromyography-assisted activity program. Some studies are being conducted on this using a body-weight-support harness over a treadmill. The initial data looks promising. For now, the best evidence-based approach would be a passive standing program. The child should be placed in a stander for 60–90 minutes every day; the time can be broken up into three 20-minute increments.

For our case study, 8-year-old Makayla had some use of her arms. To encourage strengthening of her accessory-breathing muscles, we chose a stander with large wheelchair-type wheels that she could push. Makayla also enjoyed the freedom of moving around her classroom and keeping up with her friends. For a child with a higher or more complete injury, a few companies make standers that drive like power wheelchairs. You can use a joystick or switches.

KNEES

Makayla, like many children with spinal-cord injuries who spend most of their time sitting and have mild to moderate spasticity, has tight hamstrings. While it may seem enticing to try to stretch the hamstrings while she is in the chair through the use of elevating leg rests, this is not acceptable. Never use elevating leg rests to stretch tight hamstrings. The child will merely externally rotate and flex to avoid the pain. Elevating leg rests can’t even help with edema unless they are combined with tilt so that the feet are elevated above the level of the heart. The best approach for Makayla will be to wear long leg splints or knee immobilizers (with her ankle-foot orthoses on) while she sleeps. Research has shown that it takes 6 hours to adequately stretch spastic muscles. The hamstrings are two-joint muscles. They are best stretched when the hip is flexed and the knees are extended. A long leg sitter proved helpful for Makayla to stretch her hamstrings during the day. We had to start gently, allowing lots of knee flexion and stopping external rotation. Some kids may even need to start with a bit of knee flexion and hip extension to tolerate this position.

FEET

Choosing the right footrest/foot plate can be like playing darts in the dark. The shoe may look great—flat and well-supported—but inside, the foot may be twisted and plantar-flexed. The secret is to look at the child barefoot or in their brace, and make the footrest/foot plate, angles, and orientation match their foot/ankle/knee alignment rather than making their foot look like the foot plate. When ordering the chair, get an angle-adjustable and rotational foot plate so that you can angle it in space and accommodate whatever comes along.

Using the TOILET

When Makayla does her bowel and bladder program, we need to make sure that she is provided with adequate support and postural alignment, adequate cushioning to preserve skin integrity, and the ability to facilitate function (self-catherization and privacy while waiting for elimination). The same principles as for wheelchair seating apply here. Footrests at the correct angle and orientation are essential so the feet can be loaded. Most children need to lean forward in order to have a successful bowel movement. A tray (upper-extremity support) may be key to helping the child relax enough and still lean forward.

BATHING

There are two approaches here: active versus passive sitting. If the child wants to play in the tub, they need to be sitting upright. Some bath supports allow this. If you choose this approach, a wrap-around-trunk support and a well-placed piece of dycem can allow for function and access to the areas that want to be washed.

If you pick a bath chair that allows the child to lay almost flat on their back, make sure the material has some give and is not damaging to the child’s skin.

Ginny Paleg in an NDT-certified pediatric  physical therapist in Silver Springs, Md. She splits her time between the Montgomery County Infants and Toddlers Program and teaching continuing education programs. She can be reached at ginny@paleg.com.