Do it for the Children: Designing Medical Devices for Pediatric Patients

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By Matt Skoufalos

For more than 30 years, surgeon Alvin Crawford worked to help thousands of children with pediatric orthopedic conditions and spinal deformities correct congenital issues and reach their growth potential. He’s the founding director of the spine center that bears his name at Cincinnati Children’s Hospital Medical Center, a professor emeritus at the University of Cincinnati College of Medicine, and an innovator in surgical techniques and implantable medical devices that serve a pediatric population.

Working in this area of expertise for so long has given Crawford an authoritative perspective on the distinct and specific needs of designing technology for use by pediatric patients, as well as allowing him to witness the unfolding of those plans along a decades-long timeline as he follows his patients to skeletal maturity. Designing for children, Crawford said, is contingent upon a handful of particular needs, most of them centered on the fact that unlike adult patients, they grow and change. That means designing “for their current as well as their potential sizes.”

“In pediatrics, it’s a continuous learning process; almost all kids present to you differently,” he said. “The most important difference between the adult and the child is that you can’t injure their potential to grow. You’re trying to pre-empt any particular danger that could occur to the child as they’re being treated; you want to see how their growth and development continues. It’s not a one-size-fits-all.”

Far from being a one-size-fits-all approach, many medical devices that are commonly used in the treatment of children may be custom-developed because an out-of-box solution simply doesn’t exist. In some instances, physicians are required to modify existing products for use by children; in others, they may be called upon to develop custom solutions to congenital issues that are specific to the cases they see.

Managing hip, foot, and spine issues to help children develop along a normal timeline has led Crawford to contribute to the design of devices that are adjustable over 10 to 15 years; skeletal maturity is about 13, 14 in girls and up to 17 in boys, he said. He’s seen patients on a much longer timeline than many other health care specialists might; has seen them transition through different developmental phases in their lives. Some of that is because he’s done the bulk of his work in the same general geographic area for much of his career, and “[being] in one place for a long time [has] given me the opportunity to see things that one wouldn’t normally,” Crawford said.

But it’s also given him the opportunity to evolve his approach to treatment and care of pediatric patients because he’s learned from them as they’ve grown. Another of the biggest takeaways after years of designing for kids: the safety factor “is altogether different” for children than adults.

“Children like to experiment,” Crawford said; “they like to do stuff. You can’t have a device that hurts them when they get out of the bounds that you put them into. Whether it’s radiologic or mechanical, there has to be automatic safeguards so that if a child starts to manipulate it, it shuts off.”

Manufacturers will stress-test devices in consultation with clinicians, but their repetitive and mechanical external approaches are meant to simulate conditions that are sometimes very different than those inside the human body. (Even models generated from simulations with animal models have their own safety constraints, Crawford said.) However, as children grow and develop, updating implanted devices accordingly used to require multiple surgeries in the same areas of the body, exposing children to the risks of infection and repetitive stresses on growing tissue. Innovations that have shown promise in limiting complications from surgery include implantable devices that can be externally adjusted once installed.

“Nothing is easy, but in terms of the spine, we put devices like growing rods for scoliosis,” Crawford said. “Getting underneath the skin repeatedly, you can let bacteria in, making it subject to infections and wear and tear, whereas a magnetically controlled growing rod for spinal deformity is a tremendous advance.

In a scoliosis patient, you can perform the definitive procedure when they reach skeletal maturity.”

Of course, as Crawford points out, “there’s nothing that a kid can’t destroy, and that’s why it’s important to image them.” Designing technologies that are able to be scanned safely to monitor children’s growth is a key consideration; this can mean working with a variety of materials that can stand up to the “potential effects of the child wanting to be a normal child; running, playing, and so forth” as well as those of routine diagnostic scans, he said.

“What’s required of imaging is making sure we can follow [growth], and imaging is the only way we can do it,” Crawford said. “We can do it with ultrasound to decrease [the impact of ionizing] radiation as much as possible.”

When designing for imaging patients, the principal focus for medical device manufacturers is creating technology that relies upon the lowest possible radiation dose without sacrificing image quality. But when those patients are children, different considerations come into play.

Some technologies are designed to keep them comfortable — and, most importantly, still — during imaging procedures. Virtual reality (VR) units can help soothe a young patient, and environmental controls for adjusting the sensory experience of an imaging study can, too. Other approaches are centered on accelerating the speed of a procedure, limiting the amount of time a child is asked to sit for a study and therefore the occurrence of motion artifacts. Some advances in the sensitivity of non-ionizing systems, like ultrasound, are showing greater detail in infant vascular systems. And the revolution in 3D printing technology is allowing surgery pre-planning and custom modeling to take much of the guesswork out of incredibly complicated procedures.

But for all those improvements, said Mario Pistilli, Director of Imaging and Imaging Research at Children’s Hospital of Los Angeles, there’s still a major concern: how to pay for them.

“It’s unpalatable to talk about money,” Pistilli said; “the fact is, we have to be able to survive. They’re injecting cash to get [these technologies] developed on the front end, but if it’s not reimbursed on the back end, it doesn’t help. You can’t adopt everything that doesn’t pay, so you have to be very smart in how you do that.”

Asking billing codes to catch up with emerging technologies is a tall order; as Pistilli said, “If there’s not reimbursement, it’s hard to get it off the ground.” The best hope for many emerging devices is to show the return on investment that potentially pricey innovations can yield in terms of patient throughput, customer growth, and partnerships with deep-pocketed educational or private institutions.

Entrepreneur Tim Moran of Cleveland, Ohio, is the founder of both PediaVascular, a medical device company that developed and markets FDA- and CE-approved pediatric angiography catheters, and of PediaWorks, a pro bono consulting and advocacy nonprofit that advances the research and development of additional pediatric medical technologies. In addition to putting his specialty catheters on the market, Moran is an advocate for the expansion of the field of pediatric medical devices, which he said is underserved by medical device manufacturers who don’t see enough financial potential in making products for a small patient group.

“Typically, the hurdle for a big company is a market size of a couple hundred million at a minimum,” Moran said. “Even if a product might be profitable, they haven’t hit that revenue threshold. For some companies, it’s a great niche business, but all the development costs are still there. If you’re not getting some sizable grant funding, you’re not going to make it.”

The biggest medical device companies typically don’t look at the pediatric space outside of the neonatal intensive care unit (NICU), Moran said, which results in the off-label use of other, FDA-approved processes; what he describes as “physicians acting like MacGuyver, manipulating these devices themselves.”

“Kids are not just small adults,” Moran said. “Their anatomy is different and the structure is different; getting access to it is too.”

Pediatric patients may account for less than 10 percent of all medical device use, Moran estimated, and there’s a significant need among them for medical devices tailored to their anatomy and needs. Without a considered approach to getting those technologies to market, however, a viable business model can be elusive.

“You can’t do the standard approach,” Moran said; “You can’t build up a big, fixed-cost structure, as you would typically. This really has to be done from an outsourced, bare-bones structure. You don’t need a full-time team to get this stuff to market.”

PediaVascular products “are in every pediatric cath lab in the U.S., and we sell direct,” Moran said. Even so, the market size is so small that the business doesn’t justify having more than himself and a part-time employee to do that work. This might be antithetical to the way traditionally built corporations operate, but the pediatric medical device market also has gained another bit of support from the U.S. Food and Drug Administration (FDA) that helps level the playing field.

In 2009, FDA established the Pediatric Device Consortia (PDC) Grants program, an offshoot of its Office of Orphan Products Development, which is mandated to “advance the evaluation and development of products (drugs, biologics, devices, or medical foods) that demonstrate promise for the diagnosis and/or treatment of rare diseases or conditions.”

Five regional consortia work with inventors who have an idea for a pediatric medical device, whether through market research, internal design work, or competitive grant awards. They contract with outside experts to support the business development and research that a larger, private corporation might provide from its own resources, and which is invaluable to smaller, developmental-stage companies. For most private enterprises, it’s a marked change in the way they’re used to dealing with FDA.

Pediatric medical devices represent “a large number of needs that are not adequately met by device manufacturers for a variety of reasons,” including the cost and the risk of conducting pediatric trials for patients with significant diseases, said pediatric cardiologist Robert Levy.

Because the market won’t take on the challenge of making pediatric-specific medical devices, manufacturers are “throwing the burden on the physicians who take care of those children” to use off-label items in their work, Levy said. Leveraging the resources of the Pennsylvania Pediatric Medical Device Consortium (PPMDC), for which Levy is the principal investigator and chair of the clinical and scientific advisory committee, helps foster the development of various kinds of pediatric devices to resolve these issues.

“The off-the-shelf equipment just isn’t there,” Levy said. “We’ve now assisted more than 100 different organizations. Some of them have been startup companies; some have been universities trying to roll out their technology.”

Having the FDA’s official support helps a lot, he said. The PPMDC oversight committee is composed of current or former executives from throughout the medical device community, including representatives from the ADVAMED pediatric division, venture capitalists, and former regulatory experts. In the time since its inception, the agency has brought nearly 20 projects to market, and others are in trials. Five large grants are awarded annually, and five early-stage concepts are handed over to a local design group, Archimedic, which helps them flesh out the next stages.

“We stay in touch with everybody,” Levy said. “We’re always reviewing other ideas of in-kind support. We have a regulatory specialist who’s under contract to us as a consultant; many of the people we talk to, we connect with him.”

Others can benefit from consulting with the consortium, which also supports companies’ pre-submission product meetings with FDA. PPMDC members often conference-call into those meetings to provide a pediatric perspective for the discussion. The grassroots process is a different one from which many medical devices are developed, but so far, it’s yielded encouraging dividends in a critical area of need, Levy said.

“The approval process is still rigorous, but it makes it somewhat easier for companies to get into it,” he said. “It’s really exciting, and I think progress is being made.”

As technology progresses to FDA approval, prototyping for pediatric devices increases the sample size required for adoption. Proving that use error is unlikely among pediatric patients requires studying children’s interactions with the devices as well as those of adults. The testing isn’t that different, but children tend to make different kinds of mistakes “because of all of the obvious differences between children and adults,” said Stephen Wilcox, principal of the Philadelphia, Pennsylvania-based Design Science.

Aside from children’s ability to unintentionally damage technology by using it in contraindicated ways, designing for young people means considering the developmental differences between children and adults.

“The way the testing unfolds is not necessarily that different, but the nature of the errors is different, which means that the design implications of the errors we observe is different,” he said. “The problem that all of us have in product development is that we always think the person we’re designing for is going to be more like us than they actually are. The challenge for us is to look at it more from the point of view of the person who’s going to use the device and not let our knowledge and biases drive the information.”

When designing for children, Wilcox points out that it’s hard for adults to remember what kids don’t know; “what all of us didn’t know at a certain age.” Sometimes designers will struggle to explain how something works, “and sometimes the kid just won’t get it, whereas that would be rare with an adult,” he said. That’s a clue for designers that they’ve either got to rethink the design or really restrict the age of use.

“If there are procedures, we’ve got to imagine how easy it is for a young child to remember the procedure so it’s not error-prone; particularly not in a way that it’s dangerous,” he said.

“Often an adult’s involved, so you’re really designing for children and parents, and much of the time, the parent’s are going to use [the device] in sometimes unpredictable ways, too.”

Regardless of the work that it takes to innovate pediatric-specific devices, the financial cost of doing so, or the time involved in honing it to perfection, the moral mandate to care for the most vulnerable patients is one that cannot be overlooked. ICE

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