Pediatrics Series

Crumbling Walls

Understanding the Challenges of Mobilizing Clients with Osteogenesis Imperfecta

Osteogenesis ImperfectaTo understand osteogenesis imperfecta (OI) — a condition commonly referred to as brittle bone disease — first picture the walls inside your home.

“In a basic wall, for it to stand up, you have to have certain-size studs, and they have to be a particular number of inches apart so that wall will stand,” explains Mary Beth Huber, director of program services for the Osteogenesis Imperfecta (OI) Foundation. “To that you attach your wallboard, your mineral.”

Think of those wall studs as collagen, the most prevalent protein in the human body, responsible for giving bones structure.

Some people with OI have normal collagen, but they have only a third or half as many “studs” in their walls as they need, Huber says. Therefore, when you attach mineral to those studs, the walls are likely to fall.

That is an apt metaphor for type 1 OI, which accounts for 50 percent of all cases and manifests with mild symptoms including bone fragility, some fractures and minimal limb deformities, according to the OI Foundation.

In other types of OI, the collagen, or wall stud, is simply not as sturdy as it should be. Huber says these wall studs are constructed of a material more akin to balsa wood than 2x4s.

Genetic abnormalities cause these changes in the body’s production of collagen. Eleven types of OI have been identified based on different genetic mutations (of which there are hundreds) as well as the severity of symptoms — ranging from mild to moderate to severe, according to the OI Foundation.

“The part that we always encourage people to understand is that OI is so variable,” Huber says.

The Collagen Challenge

While OI does cause a fragile skeleton with frequent broken bones or fractures, those symptoms describe only half the story.

“All collagen-rich tissues are affected,” Huber says. “So additional symptoms include loose joints, low muscle strength, and weak tendons and ligaments. Shoulders and elbows may dislocate. Bone deformity and significant short stature are seen in the moderate and severe forms. Additional symptoms include respiratory complications, fatigue, hearing loss, dentinogenesis imperfecta and other oral cavity problems.”

Respiratory complications tend to be the most serious, and those with more severe forms of OI might experience a shortened lifespan because of related respiratory issues.

“Lung tissue contains a significant amount of type I collagen,” says Petra Harvey, health educator for the OI Foundation. “All people with OI have some degree of respiratory compromise and are at risk for serious respiratory infections. Scoliosis and ribcage deformities make respiratory problems more severe.”

Plotting a Course for OI

Many people with OI live long, full lives that include careers, community involvement and children.

The good prognosis brings its own challenges, however, as orthopedists and other healthcare providers must make decisions to plan for the long term. Harvey lists the following as the top considerations to accommodate a longer lifespan:

  • Helping children relearn motor skills aft er rodding surgery or a lengthy cycle of fractures and immobilization.
  • Managing fatigue and chronic pain.
  • Dealing with scoliosis (the most frequent progressive deformity) and hip and knee problems possibly caused by awkward walking gait.
  • Recognizing that fractures are most common from childhood to puberty and again aft er menopause, and that tendon, ligament and muscle injuries increase during teen and early adult years.
  • Planning for differences in stature, as people with severe OI might be in the 3-foot to 4-foot range as adults.

In many cases, OI is first suspected around the time toddlers begin walking. A clinical evaluation helps rule out other conditions, and a DNA analysis confirms the diagnosis, Huber says.

The OI Foundation estimates that OI occurs in one in 15,000 births and that 30,000 to 50,000 people of all ages are currently living with OI in the United States. Approximately 90 percent of OI cases are inherited directly from an aff ected parent or caused by spontaneous mutation.

Depending on the severity of OI, treatment might include repairing fractures and surgery (rodding) to reinforce long bones or reduce bone curves/deformities, physical and occupational therapy, lifestyle management strategies including mobility equipment, and bone-building drugs such as bisphosphonates, growth hormones and teriparatide.

These drugs “will treat to some extent the osteoporosis symptoms, but they do not treat the underlying OI issues. It also addresses only half the problem: It looks at the skeleton, which is a huge deal to have a fragile skeleton, but it doesn’t address any of the other collagen-related issues — muscle, tendon, ligament, lung problems — that go along with OI and are not affected by bone-building medicines that we currently have,” Huber says. “It makes a huge difference, particularly in a child with very severe OI, but it’s not the full answer yet.”

Clinician’s Blueprint: Assessment Insights

Because the diagnosis of OI is so variable, you might be wondering how to prepare for the seating & mobility evaluation. The good news is that when assessing a client with OI you can follow the same course as any other assessment: Pay more attention to the individual in front of you than to the diagnosis on the file.

“Just like with everyone else, we want to know what their goals are, how they want to live their lives and what we can do to help maximize their function in their world,” says Jill Monger, PT, MS, ATP, wheelchair seating & mobility clinic coordinator at Medical University of South Carolina in North Charleston, S.C.

In fact, the real difference lies in the goals of the equipment. “The main thing that’s different with OI is protection, protection, protection,” Monger explains. “The other huge issue is transfers. They’ve got to be able to get in and out of the system without someone lifting them or physically handling them because this puts them at higher risk for fractures.”

That means in addition to providing mobility, you also have to look at creating a safe environment for the child through the chair.

For Monger, achieving these goals involves a two-step process: (1) consider making the equipment a bit larger to create a buffer between the person with OI and his or her surroundings and (2) use power options such as seat elevation and seat-to-floor to add variability and independence in transfers.

However, even clients with the same types of OI can have different goals.

Tamara Kittelson-Aldred, MS, OTR/L, ATP/SMS, who works at Community Medical Center in Missoula, Mont., and is the founder of Eleanore’s Project, has worked with two children with type 1 OI.

One was a young girl in Peru who needed a wheelchair mostly for protection, to prevent falling and fractures, Kittelson-Aldred says. The other was a young boy in Missoula who needed a wheelchair only when he had a fracture. The rest of the time he walked.

Another critical difference in an OI assessment is deciding how much to handle the client. Again, that decision depends greatly on the individual client.

Kittelson-Aldred is typically very hands on when evaluating children with mobility conditions to assess head and trunk control, range of motion, sitting and posture.

“I was able to do that with a type 1 kid that I know, but the little girl with type 3, it was actually the first wheelchair evaluation I have ever done where I have not laid my hands on the child,” she says.

Kittelson-Aldred found out that even the child’s father did not pick her up. What’s more, this particular child had fractured herself when getting upset just by throwing herself around a little.

“I really didn’t want to take that risk to tell you the truth. I would’ve been really careful, but given all of the anxiety about it, I didn’t want to take a chance,” Kittelson-Aldred says. “Basically I had her mother move her in the ways that I wanted to see her move so that I could see what her range of motion was like and see what her head control and her trunk control were like. … And that’s not something that I would ever usually do, but that’s what I did in that situation.”

Monger, on the other hand, does handle children with OI, but says doing so is not without risk.

“I do handle them, and I’m very careful,” Monger says. “But again as a PT who’s been doing this for almost 30 years, I’ve had people break in my hands, whether they’re OI or someone with spinal cord injury who has extreme osteoporosis. It’s not a pleasant experience but also not always avoidable.”

Monger believes that’s a risk you have to take because you can’t build a system that will protect a patient if you don’t know what joints move or what limitations they have. But even Monger is especially careful when it comes to transferring.

“If they can transfer themselves, I’m going to find a way to let them do that,” she says. “Or if they have someone who transfers them on a regular basis, I’m going to have that person transfer them for me.”

Barbara Crume, PT, ATP, a seating & mobility clinic specialist at CarePartners Health Services in Asheville, N.C., also does what she can to minimize the risk of fractures, and that means not giving a manual muscle test.

“I will look at them functionally, what they can do, but I won’t give resistance to their movement,” she says, because of the risk of fracture.

A Case for Manual or Power

Choosing manual or power chairs often depends on the type of OI and the goals for each client. The environment also plays a deciding role.

Crume cites a case of a 2-year-old with type 3 OI who was a prime candidate for a power chair because he already had fractures in his arms.

“I was very concerned for him to even push a manual chair,” Crume says. In addition, the child had some discomfort in his pelvis.

“I thought if we could do a little power chair with tilt he could stay in the chair and tilt back off his bottom and be more comfortable throughout the day,” Crume says. “But I couldn’t do power because (the family) had no means to transport it, and in North Carolina, Medicaid will not cover the cost of a power chair if the family can’t transport the power chair.”

Instead, Crume recommended an ultralightweight, rigid manual chair.

For Monger, the clients who have wanted manual chairs have been very clear about their expectations.

“They don’t always want it to be very light because they don’t want it to feel like it can turn or flip,” she says. “They often actually want a little bit of a heavier chair.”

Even when prescribing power chairs, Crume asks very specific questions about transferring. For example, she recommended a power base with a power seat elevator for a child with type 1 OI who was starting to get fractures in his upper extremities and clavicle. However, the family did not have him use this chair.

“They weren’t able to transfer him the way they were used to transferring him,” Crume says. “This was an unusual case — it turns out the way the dad had to pick him up from behind to support the child’s spine against his own trunk, he could not do it now in the power chair because the back came up too high.”

So when the child was eligible for a new chair, Crume recommended a folding cross-frame power chair. The back post had a hinge so that the frame could fold down.

“It looked like a manual chair but with motors,” she explains. “The dad could release that hinge, fold it down and lift his son up that way.”

Sometimes, however, the case of OI is so severe that a power chair is really the only option.

Kittelson-Aldred has a client who is classified as either a severe type 3 or a type 2 who somehow survived. The girl has no head control and cannot sit up by herself.

“She has a power chair with everything: manual recline, tilt in space, a seat elevator. Her chair can do practically everything but talk because that’s what she needs,” Kittelson-Aldred says.

Making the Right Equipment Choices

When it comes to making equipment choices, there are three important considerations: comfortable seating and positioning, safe transferring and good suspension.

In terms of seating, Monger says that generally people with OI have good core strength, including trunk and head control. So she focuses on client comfort when it comes to seating needs.

Unfortunately, “There’s this precarious balance between them being able to slide on and off the cushion independently and having a cushion that’s soft enough for them to feel comfortable and to have pressure relief,” Monger says.

Power tilt is a good option to bridge this gap by providing a safe transferring surface as well as the comfort and pressure relief the client needs.

Wider and shorter seat depths are another variable for people with OI, Crume says. In one case, Crume positioned a boy with his legs fully out in front and the seat short with his knees bent.

“This gave him a lot more stability and balance to let him long sit in the seat,” she says.

Sometimes Crume even recommends a pediatric seating system on an adult power base because the depth is shorter.

“Adult seats usually start at 16" deep, and these guys might only need 14" deep,” she explains.

For children, the power seat-to-floor option, as found on chairs such as Permobil’s K450MX, are invaluable, especially for preschool-age kids.

“They can get down to the floor, get out of the chair themselves, scoot around on the floor, (have) story time on the floor, whatever, and then get back in by themselves without a caregiver having to pick them up,” Crume says.

This option also raises the chair to help children transfer at varying heights, Monger says.

Because the simple act of touching can cause fractures, minimizing bumping and jarring in a chair is imperative when building a mobility system.

Crume always recommends pneumatic tires to reduce the risk of hairline fractures.

“Most children and their families don’t really keep up with keeping air in the tires, so we usually recommend airless inserts and thus we really stress to these families that it’s very important that you keep the air in the tires. It gives them that suspension,” Crume says. “And we can often recommend Frog Legs [suspension components] on the casters also to help with going over thresholds and reducing impact there too to the front of the chair.”

Monger decides which shock-absorbing components to include by considering whether the chair is manual or power and if the client will self-propel or be pushed. She says shock-absorbing components are more necessary for manual chairs when someone else is pushing. In this situation, the child might encounter more challenging terrain.

“But if they’re a limited self-propeller, they’re probably not going to be going over a lot of the lumps and bumps because they can’t usually do it,” Monger says.

Many of today’s power chairs have good suspension systems built in, so shock-absorbing components are less of an issue.

In addition, an air-filled seating system can help reduce the risk of fractures. Kittelson-Aldred actually designed such a system for her client with type 3 OI.

“We actually created a fairly wide backrest for her that has gentle curves, and we lined it with ROHO cells, air-filled cells that can be inflated or deflated by her parents if they deem necessary,” Kittelson-Aldred says.

This particular system enabled the parents to deflate the air cells to give their daughter some freedom, yet have the option of filling the air cells to build in some protection or to support her when she was in pain or fractured.

Challenges Ahead

Even with the best mobility system, OI has one inherently unavoidable outcome: “They’re going to fracture,” Monger says.

Therefore, mobility equipment needs to help minimize the possibility of fractures and retain some flexibility to accommodate fractures when they do happen, Monger concludes.

The system must allow a leg or arm to be in a different position if it’s in a cast, and “That’s a tough one, especially for those who really, really want to use manual chairs,” Monger says.

Kittelson-Aldred says when someone is in a cast, power tilt can help adjust the client’s orientation, and an infl atable air cell seating system can provide support.

Another thing to consider is how treatment might affect physiological changes down the road. For example, Crume has one client whose long bones had all been rodded, but she later developed a pelvic obliquity and scoliosis.

“It’s a change of condition due to the OI over the years,” Crume says. “So we modified her seating to accommodate and provide pressure distribution for her asymmetries.”

Growth, even though minor, might also affect the mobility system. Monger says for those using power chairs, building in growability is not as much of an issue because she typically puts these children in a bigger base for protection anyway. But it’s a diff erent story for children self-propelling manual chairs.

“If someone is using a performance manual chair that they have to push themselves, the last thing I’m going to do to anybody who is trying to get their arms up on a wheel to self-propel is build it too big because they won’t be able to use it until they grow to that size,” she says. “If it’s a true performance chair that they’re going to try to self-propel, it needs to fit them now.”

Kittelson-Aldred says there is one important difference for building in growability for children with OI:

“I think the thing for kids who have OI is that they’re probably going to tend to not outgrow things as quickly because they’re not going to be as big,” she says.

Despite these challenges, an OI diagnosis is no different from other mobility conditions.

“People overcomplicate things sometimes,” Monger says. “It’s really not that complicated. It’s really all about what everybody else in the world who experiences challenges with mobility needs; they want and need to be as independent as possible and as active as possible in their world.”

OI and Viking Lore

Osteogenesis Imperfecta and the VikingsHistorians believe that Viking Prince Ivan the Boneless might have had osteogenesis imperfecta. He was carried into battle on a shield because he had difficulty walking on his soft legs, according to the OI Foundation Web site.

Search for a Cure

Although OI currently has no cure, research to improve the quality of life for people with this condition is ongoing. Mary Beth Huber, with the OI Foundation, points out the following areas of study:

  • Uncovering details about genetic causes and bone formation.
  • Identifying new targets for treatment, especially drugs.
  • Testing bone-building drugs currently used to treat osteoporosis.
  • Researching stem cell therapies.
  • Learning more about variables in how people with OI walk, including gait analysis laboratories.
  • Examining how OI changes during adulthood via longitudinal natural history studies.

“I think what we’re excited about is that there are initiatives going on in all of these now. It’s not just looking at fracture prevention; it’s not just looking at the genetics,” Huber says.

This article originally appeared in the July 2013 issue of Mobility Management.

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