INTRODUCTION OF AN INTRAORAL BONE-LENGTHENING DEVICE

Distraction osteogenesis, initially described in the enchondral bones of the axial skeleton,(1,2,6,8) has has been applied recently to the m embranous bone of the craniofacial skeleton. Preliminary studies on th e canine mandible(3,4) led to the first clinical trials in 1989 of bon e lengthening involving the human mandible.(5) Thus far the technique has been applied unilaterally in the treatment of hemifacial microsomi a and bilaterally in patients with Nager syndrome, Treacher Collins sy ndrome, and developmental micrognathia. The main criticism of the tech nique has been the residual scars along the cheek. The currently avail able devices are sufficiently large to require a skin incision along t he mandible to permit their application. As with devices used on the l ong bones of the extremity, this device lies externally, and the half- pins cut through the skin during active expansion. In order to avoid e xternal scars, we have investigated the use of a miniaturized bone len gthener (Howmedica Corp., Rutherford, N.J.) that is suitable for intra oral placement along the buccal surface of the mandible (Fig. 1 and Ta ble I).