Cranial vault moulding by the transcutaneous activation of implanted magnets.

The technique of distraction osteogenesis has not been widely used in the treatment of injuries of the head and face because of the need for external fixators. By using magnetic, rather than mechanical, forces to drive bone movement we hope to expand the applications of the technique to include the treatment of cranial vault deformities. Fifteen immature rabbits were studied. When they were 6 weeks old each had a magnet fixed to their left parietal bone. A head frame was attached and a magnet of either the opposite polarity to, (group 1), or the same polarity as, (group 2), the implanted magnet was mounted on the frame. Five weeks later the rabbits were sacrificed. There were significant differences in parietal skull width and in several measures of skull length between the animals in group 1 and those in group 2. These results demonstrate that, in this model, magnetic forces can be used to modify skull growth.