NurseWeek

Doctors grow new jawbone for 9-year-old

By Tim Bergling
Health24News
September 6, 2000


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Washington (H24N). A 9-year-old Michigan boy born without a full jawbone has a new face to look forward to, thanks to the new use of an existing technique to heal broken bones.

Doctors used a technique called distraction osteogenesis to make a new jawbone for Ryan Dewald, who was born with almost half his jawbone and one jaw joint missing, a condition known as hemifacial microsomia. In distraction osteogenesis, doctors attach a device called a distractor, an adjustable rod connected by two sets of pins, to each side of a broken bone. The rod has a gear that allows doctors to keep moving one side a little farther away from the other, causing bone to grow in the gap between.

"You cut the bone, and when you cut it, it wants to heal," said Steven Buchman, a plastic surgeon who led the effort. "If you fool the body by moving those two cut surfaces away from each other slowly, almost like a clock moving every day, you’ll fool the body into making new bone."

Previously the technique had only been used successfully to treat fractures of large bones, or to repair existing facial bones. Ryan’s case is only the second time doctors have used the method to grow bone where there was none before, by slicing a tiny portion off of Ryan’s malformed jawbone and attaching it to the distractor. Ryan’s doctors and parents were able to adjust the device, half a millimeter at a time, by turning a key attached to the mechanism through Ryan’s cheek.

The result? As much as 35 centimeters of new bone and a joint, and an entirely new structure for Ryan’s face. Buchman is confident enough new bone will be in place by early fall, when the distractor will be removed. Buchman says there’s a lot more to learn about the technique, namely, just how much bone can be grown. That question may be answered in lab tests.

Experts say some form of hemifacial microsomia takes place in about one in every 3,000 births, making it the second most common facial birth defect. There’s no known cause for the defect, and scientists don’t believe it’s linked to any behavior by the child’s mother. They say evidence exists that the condition may be genetic.