Full-body cast crash testing

Feb 16, 2007

Children with medical conditions requiring full-body casting present parents with potentially dangerous transportation options. Researchers are working on a "cure" for the problem.

Engineering a "cure" for a potentially dangerous situation, Dr. Patrick Atkinson, associate professor of Mechanical Engineering, and Dr. Julie Zielinski, M.D., M.S. orthopedic surgery resident at McLaren Regional Medical Center, are researching the safest way to transport children immobilized in full-body casts.

Atkinson and Zielinski came up with the idea to study the implications of transporting a child immobilized by a cast in a child safety restraint after both heard anecdotal information about how parents dealt with the problem of transporting children after orthopedic procedures to correct hip dysplasia or dislocation, broken limbs and other conditions related to the lower extremities.

"It makes it very difficult, if not impossible, to put a child in a car seat when they are in a full-body cast," said Atkinson. "Some parents ride home with the child in the arms of one of the parents or they lay the child in the back seat and use the adult seat belts to hold the child in case of accident, and some try to get them in the car seat using the car seat in ways it wasn't designed to be used," he added.

"Parents are already apprehensive about their child's welfare because of the casting and or surgery," said Atkinson, "this transportation problem just adds to their stress." This added stress can last between four weeks to six months, depending on the nature of the orthopedic condition and rate of healing and the number of doctor's visits required.

"We are testing all the scenarios in the Kettering Crash Safety Center," Atkinson said, "using 20 different crash tests including front and side impact and varying sizes and models of car seats." The testing is currently one-of-a kind. Similar testing was done in the 1980s, but was conducted using dolls instead of crash dummies.

Atkinson and Zielinski put full-body casts on infant and child-sized crash test dummies that have diagnostic instrumentation that indicates potential and probable injuries. "The dolls used in the 1980s did not have diagnostic instrumentation," said Atkinson, "and technology has improved dramatically in terms of analysis capabilities and how car seats are designed. It was time to run more tests."


Paul Gratsch, associate controller in the Business Office at Kettering, was on hand during some of the crash testing. Gratsch's daughter Haley, now 7, was put in full-body casts twice, at eight months and again at five years old, to correct a displastic hip. Fortunately the hospital provided the family with information on how to install and use their existing car seat to its full advantage.

"The University of Michigan Hospital did a great job of training us in the hospital room," said Gratsch, "but they didn't follow us out to the parking lot and when we got there it felt like it was all new, like we were seeing it for the first time," he said, admitting it was stressful and frustrating.

"Not all hospitals have a uniform policy on how to work with families in this situation," said Atkinson."

Approximately 2,000 children per year in the U.S. are immobilized in full-body casts. This medical procedure is commonly used because "you can't tell a child not to be weight bearing on a limb," said Zielinski. "It's better for their recovery if they are put in a cast from chest to toes to keep them off the limb and to promote healing," she added.

There is a car seat designed for use with a child in a full body cast, the Hippo car seat by Britax. "It is a wonderfully designed product, but you cannot buy it at a traditional car seat retailer, you have to know where to go to find it," said Atkinson.

What sounds like a solution to the whole issue actually has some built-in stumbling blocks. The seat is not widely publicized so most parents don't know to ask for it and many hospitals don't know it exists. Additionally, the price tag is a healthy $495, beyond some parent's financial reach. "There are local companies like Wright and Filippis, a medical supply company, that can order it," said Atkinson, but parents have to know it's available to ask for it."

Based on initial observations from the crash testing, Atkinson said that in a nut shell the long term solution centers on education. Educating parents on the resources available like the Hippo car seat or at minimum how to correctly utilize their existing car seat, educating doctors to consider modifying the cast position at the time they put the cast on and educating hospital personnel who discharge the patient to give parents discharge instructions for transportation.

"The physician may be able to bias the position of the cast on the child so it is clinically beneficial to the child but will also work best with the car seat," Atkinson said.

Their initial findings are in keeping with car seat use in general - it is better to use a car seat than not. "How you transport your child in a cast does matter," said Atkinson, "we're finding the probability of injury is directly related to how you fasten your child in a car. We saw drastically different levels of injury based on how we restrained the child dummy," Atkinson said.

The initial crash test showed there is less injury if the child is in a car seat and more injury if parents just use vehicle seat belts. And even though vehicle seat belts are not as good as a car seat, it is better to use them than for a parent to hold a child on their lap.

"As a certified car seat checker I was using the regular car seat to the maximum limit to fit the child crash dummy into it with a cast," said Atkinson, "I'm afraid the average parent who doesn't have car seat checker training would have given up long before I did."

"The Hippo seat is an important resource because you can't get some kids wearing casts into a car seat at all. The Hippo provides a way to transport kids when they are cast."

One issue that caught Atkinson and Zielinski by surprise was that the cast caused breathing difficulties when the dummy was in the car seat. "This concerns us beyond crash testing," said Atkinson, "our recommendation would be that an adult ride in the back seat with the child to monitor breathing during transportation."

Upon completion of testing, Atkinson and Zielinski will publish their data worldwide so parents can use the information to improve how they transport children during the upwards of four weeks to six months they are in a cast.

According to Zielinski, a child in a full-body cast is required to visit the doctor approximately five times before the cast is removed, forcing parents to make decisions about their child's safety for every trip. Sometimes the surgery is performed by a pediatric specialist whose office may be an hour or more away from the family's home, increasing the risk to an unrestrained or poorly restrained child because of a longer drive. Zielinski said some pediatric orthopedic surgeries are done at Shriner's hospitals and can require families to drive five to six hours for a one way visit.

Zielinski originally earned an undergraduate degree in Bio-mechanical Engineering and a master's degree in Mechanical Engineering prior to attending medical school, so the Crash Safety Center was familiar territory for her. Her work with Atkinson is one rotation of her orthopedic surgical residency through McLaren Regional Medical Center.

Written by Dawn Hibbard