Effect of maxillary distraction osteogenesis on velopharyngeal function: A pilot study

Objective. The purpose of this study was to examine preoperative and postoperative changes of velopharyngeal function in cleft patients who underwent maxillary distraction osteogenesis using the Rigid External Distraction System. Study design. Six cleft patients followed for a minimum of 12 months after maxillary distraction were examined. Plain and contrast lateral-cephalograms were obtained preoperatively and postoperatively, and speech evaluation was performed by the same authorized speech therapist at the same time points. Results. The mean distraction amount at the anterior nasal spine was 11.7 mm (range, 7.4 mm - 15.0 mm). Both the nasopharyngeal depth and velar length increased after maxillary distraction, but the need ratio (nasopharyngeal depth/velar length) also increased after distraction. Although scores for velopharyngeal closure dropped a few points after maxillary distraction, the rating for hypernasality remained unchanged in all patients but the patient whose distraction amount was 15.0 mm. Conclusion. These results suggest that maxillary distraction of less than 15 mm may not markedly affect velopharyngeal function in cleft patients.