...and One To Grow On!

Creating Seating & Mobility that Fits Today & Tomorrow

• By Laurie Watanabe
• Aug 01, 2010

It’s one of the toughest assignments in assistive technology: Build a seating & mobility system that fits a child and meets his postural needs today, while ensuring the same system, via some tweaking, will meet his needs for several more years.

Working with pediatric clients can be immensely rewarding — is there a greater feeling than helping a kid to become independently mobile for the first time? But working successfully with children and their families requires great communications skills, a talent for sleuthing, and an understanding of the child’s prognosis and future needs...not to mention being able to creatively deal with rogue growth spurts.

How Much Growability?

From a funding source perspective, the purpose of building “growability” into a seating system or wheelchair is to extend its lifespan so the child can continue to use the equipment for a longer time — thus postponing the need for the funding source to buy something new.

From a practical viewpoint, however, there is a limit to how much growth — generally defined as additional seat width, seat depth and seat height — should be built into pediatric seating & mobility.

“Generally, it appears to be good practice to build 3" of depth and 3" of back height growth into the wheelchair system,” says Sharon Pratt, PT, director of education for Sunrise Medical. “Regarding width, there is a lot of controversy. If a child’s method of mobility is hand propulsion, I try to keep within 1-2" maximum of extra width. Ideally, for optimal hand propulsion and shoulder preservation we always want the closest shoulder/hand/wheel relationship possible.”

“When you add growth into a system, you add weight to the system because what you’re really doing is adding hardware for adjustability,” says Jay Doherty, OTR, ATP, clinical education manager at Pride Mobility Products Corp. “It might be moving a backrest forward, it might be moving backcanes to their forwardmost position on a chair.” The additional weight isn’t a huge concern for power chair users “because they’re driving the power chair with a joystick,” Doherty says. “Where it really becomes a major factor is with kids with manual mobility, because when you add growth, you’re adding weight to the chair. These are kids quite often who already have compromised endurance or strength, and so you want to reduce the weight of the chair as much as possible, but still make sure you add that growth. It’s really a balancing act.”

Growability parameters can vary on other types of complex rehab equipment. Nancy Perlich, COTA, ATP, funding specialist at Altimate Medical, says, “On average, we build in 18" of overall height growth into each of our standing frames,” and adds that the standers also are depth adjustable and have growth kits.

How Does Your Client Grow?

Growth, of course, is one of the major challenges facing providers who build pediatric systems. Given that funding sources typically want seating & mobility systems to fit a child for three to five years, providers can be faced with creating a system that will fit a client from infancy through toddlerhood, from first grade through elementary school, or from the start of puberty through most of the teenage years.

While many factors can affect a child’s growth, Pete Cionitti, VP of custom seating, Sunrise Medical, says, “Research has shown that prior to puberty, width at the pelvis will average approximately 3/8" to 1/2" of growth per year. Post-puberty, this rate slows significantly. However, post-puberty there is a tendency for more tissue growth associated with weight gain that can skew this slowing effect.”

Doherty notes that most girls start their major growing between the ages of 8 and 13; boys tend to start a couple of years later and are largely done growing around age 17. “But you also need to look at diagnoses,” he says, noting that some, such as osteogenesis imperfecta, can result in shorter heights.

“You also need to look at family history,” Doherty says. “Generally, you can look at the family and get an idea of how much growth you might be looking at through the puberty years. What’s really tough is when you get mom who’s 5'2" and dad who’s 6'3". Who are they going to take after?”

BL Meyer, manager, Exomotion, notes that growth spurts can also be the result of medical interventions. “We see tremendous growth spurts that can happen from just a simple change in medication,” she says. “Very often they’re tube fed, and a change in diet can bring on a growth spurt that is phenomenal in a short period of time. You’re saying, ‘Wow, what happened?’”

Another challenge: Kids of roughly the same overall height can be longer in one portion of their bodies versus another. Says Meyer, “You may have a child who stands 40" tall, but all of their length may be in the torso. Another child is 40" tall, and all of their length is in the legs.” Those differences can be a challenge when trying to adjust systems for growth.

Dependent vs. Independent Mobility

Another challenge, especially with very young clients, is choosing between dependent mobility — e.g., “stroller”- style chairs pushed by a caregiver — and independent mobility, either a self-propelled manual chair or a power chair.

Stroller-style mobility is often popular with parents because “it’s more of a mainstream-looking piece of equipment, not so different from the general population,” Doherty says. “It’s more acceptable to moms and dads, usually, at that early age.”

Problems can arise, however, when families use their DME benefit to purchase a stroller, then decide when the child is slightly older that they want to give independent mobility a try. “You have to gauge the piece of equipment and really investigate up front with mom and dad: What are their goals and their future goals as well?”

When parents decide on dependent mobility, then change their minds soon thereafter, Doherty says a funding struggle can ensue. “Using their (DME benefit) now can put a hindrance on getting something else a little later on,” he says. “I know with the (New Hampshire) Medicaid I’ve dealt with, they’ve wanted to know that that stroller is going to last a period of time, and that you’re not going to come back in a year and say, ‘Now we want a power wheelchair for the child.’ It’s a Catch-22, because you know (the child) could benefit from a manual wheelchair or a power wheelchair.”

Building a System That Fits & Grows...

Meyer says a wide range of adjustability is crucial to being able to provide the flexibility that a growing child needs.

“It’s important in a growable system that you have seat depth and seat width and then also back height adjustment so that you can kind of customize it,” she says. “Children are all built differently, and what we find requires the most adjustment is the seat depth. The upperleg length from hip to the back of the knee is where you get a variation, where some kids have a very short length there, and you’ve got (other) kids where that is so long.”

She says foot positioning is also crucial, particularly when moving a child into a larger seating & mobility system: “Make sure you can get the leg-length adjustment correct...are their feet going to reach the footplate on that larger system?” If not, Meyer notes, foot drop can become a problem, and if the child is already wearing ankle-foot orthoses to treat foot drop, the effectiveness of the orthoses might be somewhat neutralized.

For children who self propel, it’s important to maintain good propulsion techniques. “The risk of building too much width into the chair will be poor posture and shoulder injury over time,” Pratt says.

And if the child sits too far forward in a manual chair set up with the large wheels in back, “Can they reach the wheel now?” Doherty asks. “They’re not going to have as efficient a wheel stroke (if) their shoulder isn’t in the proper location over the axle.... Quite often when you’re talking about real little ones, maybe a 3-year-old, you might be starting them out with a front-wheel manual configuration, with the larger wheel in front of them so it’s easier to reach. They see it and remember, ‘I can put my hands on that and move my chair.’”

Given typical growth rates, Cionitti says, “We can conclude that a seating system should be 2-3" wider than the hip width including the thickness of any lateral pads, since these sit on top of the cushion. The depth of the seat should be approximately 3" greater than measured sitting depth. Taken together, this should provide three to four years of growth in normal circumstances. Back height growth is less critical as this can be more easily adjusted with less mobility base constraint.”

...and Meets Providers' Needs, Too!

While children’s future needs can be difficult to predict, providers can improve their chances of meeting those needs if they’re familiar with the growability built into a system by its manufacturer.

“It is important for clinicians and parents to understand what’s involved in getting the growth manufacturers say they offer,” Pratt says. “Does it involve built-in growth that’s accessible at any time? Are new parts all that are needed, or is a whole new frame needed?”

“Clinicians, parents and providers should look for specific features in the hardware used to attach the seating system to the mobility base,” Cionitti advises. “The hardware should have three primary features: First, good range of adjustment to allow growth modifications within the envelope of the mobility base, including center of gravity adjustments. Second, ease of removability — most seating systems are often removed from the mobility base, and the ease with which this is accomplished can have an impact on system use and compliance. Third, transittested hardware to provide the best assurance of meeting existing safety standards.”

And while building in huge amounts of growth may seem great to payors, Doherty warns against it. “You don’t want a child to ‘grow into a system,’” he says, “because you’re not providing the support that the child needs then. Poor positioning can lead to orthopedic changes over time. Even if you add growth into the system, you still need to make sure when the child leaves that day, that system is set up so it fits properly.

“Parents should not hear, ‘They’ll grow into the seat cushion. They’ll grow over the next few months, and it’ll fit better.’ That’s the wrong answer.”

This article originally appeared in the Pediatric Handbook August 2010 issue of Mobility Management.