Does the Rigid External Distraction Device Allow for Long-Term Control of Maxillary Pitch in Cleft Maxillary Distraction?

Abstract

ObjectiveIt has been reported that the rigid external distraction (RED) device is unable to intentionally alter the maxillary pitch following consolidation (short term). The purpose of this study is to assess the long-term ability of RED to intentionally control the maxillary pitch.DesignRetrospective cohort study.SettingInstitutional practice.PatientsA retrospective cohort of 40 patients with cleft maxillary hypoplasia meeting the inclusion criteria.Main outcome measuresCephalometric changes and alteration in palatal plane angle.MethodsCephalometric analysis was completed standardized lateral cephalograms. Predistraction and long-term follow-up variables were compared via a paired t test.ResultsThe mean age at surgery of 12.2 ± 3.7 years. Through distraction osteogenesis, the mean change in the angles sella-nasion-A-point angle, sella-nasion-B point angle, and A-point-nasion-B-point angle were 4.8 ± 5.9, 2.4 ± 3.5, and 2.4 ± 5.4, respectively. The mean change in the palatal plane angle was -2.1 ± 4.7. The mean change in the vertical position of the anterior nasal spine and posterior nasal spine in relation to the Frankfort horizontal were -0.7 ± 4.0 mm and 0.9 ± 4.1 mm, respectively. The mean percent of maxillary advancement relative to maxillary length was 28.0 ± 12.1%.ConclusionThis study documents the long-term findings of RED in a cleft lip and palate population. Despite the design of the RED device to allow for a clockwise rotation of the maxilla, a persistent counterclockwise rotation of the maxilla was found. This study demonstrates that RED reliably allows for long-term horizontal lengthening of the maxilla but does not predictably allow for control of the maxillary occlusal plane.