Medical Devices Designed for Children

by Food and Drug Administration (FDA)

Designing a rib-replacement device for children was the easiest part of a 15-year medical crusade by Texas orthopedic surgeon Robert C. Campbell. Finding a company willing to make the device was the difficult part.

The device had to be implantable, expandable, and effective in helping children overcome lung-constricting spine deformities as they grew to reach skeletal maturity. And at the time, only one child stood to benefit from the titanium rib, suggesting limited, if any, financial incentive for the manufacturer.

Today, more than 300 children are breathing, moving, and walking with newfound hope after approval of the Vertical Expandable Prosthetic Titanium Rib (VEPTR) by the Food and Drug Administration in 2004.

Medical devices such as the VEPTR help reduce the burden of illness and injury and improve the quality of life for countless children. But the titanium rib is one of only a few devices made exclusively with the special needs of children in mind. That's because pediatric medical devices, those that treat or diagnose diseases and conditions from birth through age 21, are a challenge to design and develop. In fact, doctors often are forced to use medical devices approved to treat adults on children by making them smaller, or by mechanically modifying them to fit smaller bodies. And that widespread practice, doctors say, can be risky.

"There's a whole category of devices that you just can't shorten the length of the catheter and fix the problem for a child," says Jon S. Abramson, M.D., chairman of the department of pediatrics at Wake Forest University. "The biochemistry of a child is different from an adult."

For example, Abramson says that the active lifestyle of infants, children, and adolescents markedly affects medical devices. Some types of plastic found on playgrounds can scramble the programming of a device called a cochlear implant that allows people who are deaf to hear. And infections can be triggered by "pediatric-specific considerations," he says, such as urine contamination from a catheter placed in a diapered baby's stomach and groin area. Infections in children can lead to delayed recovery, permanent disability, and sometimes death.

While children may experience many of the same diseases and conditions as adults, kids have fundamental differences in body size, activity level, and growth over time that require special attention when it comes to medical devices. These concerns include changes in body structures and functions that occur throughout childhood, as well as the higher heart and respiratory rates and weaker respiratory muscles characteristic of children. In addition, children potentially require a medical device with a longer lifespan than those developed for adults. Concerns include device longevity and prolonged exposure to implanted materials.

Experts recognize that there is little market value for pediatric devices and that there are barriers to clinically studying their use in children. Similarly, doctors have been concerned about prescribing drugs for kids that have been tested only in adults. These types of concerns translate into little incentive for manufacturers to specifically target children with properly designed and adequately tested medical devices. Compared with drugs, devices present additional challenges due to the range of technology they incorporate and their varying applications.

"We need to know what kinds of problems exist where people have to jury-rig devices because they aren't available for kids," says Dianne Murphy, M.D., Director of the FDA's Office of Pediatric Therapeutics (OPT).

Rather than avoiding pediatric device development because of the challenges, experts say it's more important to build the foundation and resources needed to encourage device development. Murphy says this includes having a better understanding of which devices are most needed by doctors, encouraging and conducting more clinical studies in children, and improving the tracking of pediatric devices to uncover side effects.

For example, until recently, paramedics and cardio-pulmonary resuscitation students were instructed by the International Liaison Committee on Resuscitation (ILCOR) to not use automated external defibrillators (AEDs) on children younger than 8. According to the American Academy of Pediatrics (AAP), some concerns were that the machines could not identify a shockable pediatric heart rhythm accurately, and that the energy dose delivered would be too large for a small patient.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.