Title: Poster 181: Midface Distraction With an Internal Device in Cleft Palate Patients
Abstract: Maxillary hypoplasia has often to be corrected in patients after cleft palate repair to restore normal jaw function and improve facial aesthetics. This correction is done by orthognathic surgery. In spite of miniplate fixation and bone grafting many studies showed a skeletal relapse in a range of 20-30%. Distraction Osteogenesis (DO) is a relatively recent approach for maxillary advancement, with the hypothesis that slow movement of the maxilla allows easier adaptation of soft tissue and a reduction in skeletal relapse. We used an internal device to correct maxillary hypoplasia in cleft lip and palate patients. Between 2000 and 2006 13 patients were treated with maxillary hypoplasia after cleft lip and palate repair by DO. All patients had a quadrangular Le Fort I osteotomy. We used an internal distractor (Zuerich Pediatric Distractor, KLS Martin). The distraction started after a latency period of 3-5 days with a distraction rate of 1 mm per day until an overcorrection in the sagittal relationship was achieved. The distraction device remained in place for 3-4 months (consolidation phase). During this time orthodontic treatment was continued. The mean age of the patients was 18.8 years (range 14-40 years). Lateral cephalograms were done preoperative, end of DO, before distractor removal, one year later and two years later. Skeletal changes were measured by overlying the X-rays at point A. The maxilla was distracted at point A in average with 7.6mm (5.0-11.5 mm). Before distractor removal point A measured 6.8 mm (4.5-10.0 mm) on average. One year later point A measured 6.9 mm (5.0-10.0 mm) in correlation to the preoperative X-ray. There was found no change after the second year. A relapse of 10% was seen in the consolidation phase of DO. There were no major complications like non-union or failure to achieve an acceptable occlusion. Minor complications like pain and discomfort with the distractor screw were complained in 2 patients. We found a relapse in the consolidation phase of DO. Therefore overcorrection during DO is necessary to take into account the relapse in the consolidation phase. After removal of the distractor device the skeletal situation remained stable. DO may be an alternative to conventional orthognathic surgery in the cleft palate patients for correction of maxillary hypoplasia.