Medical Devices Needed for Children

By Carol Rados

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.

A recent advisory statement from ILCOR, however, says that newer AED models may be used on children older than 1. An AED is made child-capable by attaching smaller pads that deliver smaller energy doses. And the pediatric pads are clearly marked and packaged in a different color from the adult pads. The user, however, must decide which pads--adult or pediatric--to connect to the person in need. The electrode plug on the pediatric model is shaped like a bear.

Fostering the development of more medical devices designed just for kids is part of a law requiring the FDA to report to Congress major barriers to the development of pediatric devices. To do this, the FDA has sought comments from consumers, researchers, health care practitioners, the device industry, and professional and trade associations on the needs for such devices. Those who have an interest, such as the AAP, the Elizabeth Glaser Pediatric AIDS Foundation, and AdvaMed, have played host to a series of related meetings to discuss doctors' most urgent device needs and potential solutions to the barriers to bringing more pediatric devices to market.

Comments represented by the various groups surrounding the lack of device availability for kids and the barriers to development were economic, clinical, and regulatory.

The cost of developing pediatric medical devices, for example, has been reported as the most significant barrier to their development. This challenge included not only the limited size of the device market, or need for the device, but also the return on the investment required to develop and test pediatric devices, which usually falls below the profit goals of most medical device companies. Companies sell far fewer devices for use in children than in adults, for example, yet both pediatric and adult devices may require extensive and costly testing to meet the FDA's approval standards. Liability issues, concerns about lack of patent exclusivity, and lack of health care reimbursement also were raised.

The clinical barriers to pediatric device development include the belief that pediatric trials are unethical and that there is limited enrollment in such trials by prevalence of disease or condition, a reluctance of parents to enroll their children, and concerns about exposure to additional testing, such as X-rays and blood samples.

The regulatory barriers include a need for more device-specific guidance for both new devices and modifications to existing devices, and frequent size changes requiring additional regulatory activity, retooling, and remanufacturing.

The FDA determined from the comments that it was too early to recommend substantive policy, regulatory, or legislative changes involving the regulation of pediatric devices. Rather, the agency believes that to successfully foster device development, the next step is to conduct a needs assessment, with the help of interested people and organizations, to determine the unmet device needs in children. This assessment should not only provide a better understanding of the unmet pediatric device needs, but it should also help identify the barriers and potential solutions to encouraging pediatric device development.

According to Joanne R. Less, Ph.D., Associate Director for Clinical Research and Government Affairs in the FDA's Center for Devices and Radiological Health (CDRH), the agency is committed to supporting the development and availability of safe and effective pediatric medical devices, and is striving to do so without increasing the risk to children, putting an undue burden on industry or the agency, or delaying device approvals for adults.

"We want to help make more pediatric devices available but not at the expense of safety or effectiveness," Less says.

To further this effort, CDRH issued several guidances that focused on pediatric device issues. One guidance, for example, describes the types of safety and effectiveness data needed to support marketing of pediatric devices and the protection measures that should be followed when children are involved in clinical trials of medical devices. CDRH also recently established a pediatric steering committee to help coordinate pediatric-related issues within the Center, as well as within the FDA's OPT.

In its report to Congress and through ongoing efforts, the FDA stressed the importance of using children's hospital networks to: help identify the problems occurring because of a lack of pediatric devices, facilitate adverse events reported with the use of devices, and develop clinical study sites for children. The FDA plans to improve communication about pediatric devices between health care providers, manufacturers, and patients with the help of its Pediatric Advisory Committee, its pediatric steering committee, and other offices within the FDA.

Doctors agree. "I think we should make the point that there's an ethical responsibility to assure that we have safe and effective devices for use in children for the various diseases they have," Abramson says.

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