Nasal profile changes after maxillary impaction and advancement surgery.

PURPOSE: The profile changes in the nasal tip and columello-labial region that occur after maxillary advancement and impaction surgery were measured to test the hypothesis that a subspinal osteotomy would induce less nasal tip change and would result in a more acute columello-labial angle than a conventional Le Fort I-type osteotomy.

PATIENTS AND

METHODS

The lateral cephalograms of 2 matched groups of 23 advancement/impaction cases with and without subspinal osteotomy were analyzed electronically.

RESULTS

There was no difference in nasal tip elevation and change in nasal tip projection between the 2 groups. The columello-labial angle was, on average, unchanged by the surgery. A linear correlation with a weak clinical relevance could be demonstrated between nasal tip projection and maxillary advancement in the group that was treated without subspinal osteotomy. Such a correlation was not detected for nasal tip elevation in either of the groups. Palatal plane rotation had a significant influence on nasal tip projection but not on tip elevation in both groups. The correlation was strongest in the group treated conventionally. The multiple regression equation with maxillary advancement and rotation as predictors had a r2 of .6071 (nasal tip projection = 0.9 + 0.19 maxillary advancement + 0.18 palatal plane inclination) in this group.

CONCLUSION

The results indicate that the advancing piriform aperture pushing on the alae, and not the nasal spine, is responsible for the increase in nasal tip projection. The subspinal osteotomy is not superior to the conventional Le Fort I-type osteotomy in regard to minimizing nasal tip changes and obtaining control over the columello-labial angle.