Schoenleber, Pratt Fellow, Maps the Growing Human Skull
As children grow, their skulls grow with them. But physicians have lacked a good description of that developmental process, and a reliable way of recognizing early when something goes awry.
Pratt Undergraduate Research Fellow John Schoenleber, a biomedical engineering major from Columbia, Mo., is working with Assistant Professor of Radiology and Biomedical Engineering Srinivasan Mukundan Jr. on a project designed to fill that knowledge gap. His goal is to create a series of quantitative models of the skull that define what constitutes normal development as children grow from birth to age six.
The advance could prove a boon to kids with craniosynostosis, a birth defect characterized by the premature closure of one or more joints between the bones of the skull before brain growth is complete.
“The pediatric skull essentially consists of eight plates,” Schoenleber said. “As the brain grows, those plates expand. Craniosynostosis is a problem where the plates fuse early, causing the skull to bulge backwards to accommodate the growing brain. The effects on health and appearance can be tremendous.”
Without a reliable way of characterizing normal versus abnormal skull development, the initially subtle condition can sometimes go undiagnosed for a time, until symptoms worsen, Schoenleber said. On the other hand, some kids’ misshapen heads correct themselves, without the need of medical treatment, he added.
Schoenleber’s research required him to first pore over CT scans taken of kids who had suffered minor head injuries, in search of those considered normal.
“I had to learn about the structure of CT scans, to find normative ones,” he said. “It’s amazing how quickly you learn. By the end, I noticed even small differences.”
Those normal three-dimensional CT scans where then measured at points across the entire surface of the skull using a computer code created by a previous Pratt Fellow, to create quantitative digital maps of normal skull variation. While his original goal was to characterize five normal skull scans for boys and girls representing 10 different ages, the team soon realized they wouldn’t stop there.
“The skull grows a ton as the brain is growing,” he said. “That’s one of the problems. The database isn’t quite big enough yet to be satisfied.”
In addition to his models’ potential utility in diagnosing abnormalities of the skull, Schoenleber’s mapping database could also serve as a useful tool for surgeons, like pediatric plastic surgeon Jeffrey Marcus of Duke University Medical Center, in their pre-op planning for procedures that require them to literally take apart a malformed skull and put it back together normally.
“Surgeons have to take a skull, cut it into 20 pieces, and eyeball it to make it normal,” Schoenleber said. “There’s no quantitative description of what it should look like.”
Schoenleber is now examining the abnormal scans of kids with one form of craniosynostosis at multiple time points: before surgery, just after surgery and one year after surgery. The goal is to create a more quantitative method for gauging the success of a reconstructive surgery immediately after an operation.
He said their team is also exploring the possibility of working with imaging companies to incorporate protocols into CT scan software that would automate comparison of an individual child’s skull to a database of normal skull scans. Schoenleber said his model might also find use in other arenas: for example, the design of more realistic pediatric crash test dummies, like those under development in the laboratory of Roger Nightingale, an associate professor of biomedical engineering and orthopedic surgery at Duke.
Schoenleber grew up building tree houses and forts in his Missouri hometown and, for him, math and science were always fun. While he had an early interest in medicine, he soon realized that he would rather approach the field from an engineering perspective. After a semester studying abroad in New Zealand, Schoenleber has become an avid traveler, exploring seven countries, including France and Iceland, in the last two years. He plans to develop his business expertise after graduation through a job with a strategic consulting firm.