Researchers at the University of Michigan Health System are looking at how and why distraction osteogenesis works by studying rats and have found clues to the uneven clinical results. They will present their findings Wednesday at the American College of Surgeons Clinical Congress in Chicago.
Distraction osteogenesis is a method of regrowing bone in which the fractured bone is pulled apart millimeters at a time. As the fracture begins to heal, surgeons tug the bone further apart, tricking the body into thinking it must still work to heal the fracture. The body then begins to grow new bone to fill in the gap.
In two studies, UMHS researchers looked at distraction osteogenesis for reconstruction of the jawbone after radiation therapy. In one, the rats were given a low dose radiation; in the second study, the rats got a high dose of radiation. In both studies, new bone was formed. But looking at the new bone under a microscope revealed that it was of poor quality. There were obvious holes within the tissue and the bone was thin and brittle, showing signs of osteopenia (a precursor to osteoporosis). The high-dose radiation resulted in even lower quality bone.
"Clinical researchers are significantly limited in their ability to analyze their success and failure at the level of the bone. It would be difficult and invasive to take specimens from an actual patient's bone after reconstruction and study the quality and strength. With our rat model, we can cut out the new bone and examine it. We can show that although you can distract, there are some problems with the bone after radiation, and we can determine what those problems ar