Mandibular lengthening with an implanted motor-driven device: preliminary study in sheep

Distraction osteogenesis with external or intraoral devices is an establish ed method for lengthening human mandibles. In this preliminary study in thr ee sheep a newly designed, fully implantable electromechanical device for m andibular lengthening was used. After osteotomy, the device was screw fixed to the mandible, and the power and control unit was inserted subcutaneousl y in the neck region. After a healing period of five days, the device was a ctivated magnetically, allowing calibrated distraction steps of 0.04 mm/h, resulting in a total of 1.0 mm/day, Over a period of 14 days, a maximum man dibular lengthening of 13.6 mm could be achieved without transmucosal activ ation. Depending on stability of the screw fixation, membranous and/or cart ilaginous bone formation was observed in the callus by radiological and his tological evaluation. Further experimental research is ongoing to prove the clinical usefulness of this device.