抄録
Since distraction osteogenesis is considered to be a so-called low stress treatment, it is applied also to growing children with maxillofacial deformity. In particular, maxillary distraction has been performed for children with cleft lip and palate often accompanying maxillary deficiency. However, in Japan, there are no reports comprehensively describing the treatment results of maxillary distraction for growing children with cleft lip and palate. The rigid external distraction (RED) system is a typical external device used for maxillary distraction. This review describes the maxillary change on CT images, the hard and soft tissue changes on the profile, and the change of velopharyngeal function after maxillary distraction using the RED system. These examinations revealed that bone formation in the distraction gap was accomplished 6 months after the maxillary distraction, and the postoperative change of the maxilla also tended to reduce simultaneously. However, over the long term after the distraction, reduction of overjet and overbite, and occlusal stability due to mandibular growth were observed. The movement amount of the hard tissue in the distraction was significantly more than that in the conventional surgery. However, the movement ratio of the soft to hard tissue in the distraction was equal to or more than that in the conventional surgery. Although there were no children who had undergone a very large distraction of more than 15 mm, no deterioration of the velopharyngeal function was observed in any of the cases. One of the problems of maxillary distraction in childhood is that it is very difficult to determine the treatment goal because mandibular growth is still progressing. The other problem is that it is difficult to use bone-borne appliances for the maxillary distraction because permanent tooth-germs exist in the maxilla. For the same reason as the latter, bone plate osseointegration after the distraction for reduction of the relapse and early removal of the distraction device is also difficult. In the present review, maxillary distraction of children was performed up to the level of catching up the mandible at the treatment point in time without overcorrection. This was because improvement of the masticatory function was considered to be more important than jaw morphology for growing children. Although it is very difficult to examine how maxillary distraction to catch up the mandible affects the subsequent mandibular growth in relation to improvement of the occlusal and masticatory functions, this problem should be solved when performing maxillary distraction for cleft children in the future.
