Velopharyngeal anatomy and maxillary advancement.

This study was undertaken to evaluate the radiographic changes in the static velopharyngeal mechanism following total maxillary advancement. Records of 21 patients treated for maxillary retrusion were evaluated. Two groups were present: 13 non-cleft patients and 8 cleft-lip patients. The findings demonstrate an anatomical change in the velopharyngeal mechanism following total maxillary advancement. A similar change occurred in both groups; however, the magnitude is differed. The angle of the soft palate to hard palate increased with surgery (2 degrees per mm. advancement noncleft and 1 degree per mm. cleft). An increase in soft palate length was also seen (.5mm. per mm. advancement non-cleft and .4 mm. per mm. cleft). A pharyngeal need ratio prediction method was established (pharyngeal depth/soft palate length). A ratio of .68--.84 in this study was observed. A ratio greater than one was found to indicate probable velopharyngeal incompetence.