The effect of Le Fort I maxillary impaction on nasal airway resistance.

To evaluate the effect of maxillary superior movement via Le Fort I osteotomy on nasal airway resistance, eleven Caucasian patients whose surgical orthodontic treatment included Le Fort I impaction (range 2 to 8 mm, mean 5.3 mm) were selected. Nasal airway resistance in these patients was determined a few days before and approximately 8 weeks after the Le Fort I surgical procedure. Nasal airway resistance was determined by means of a uninasal active mask rhinomanometric technique. Contrary to the predicted negative effects of maxillary superior movement on nasal airway function, there was a statistically significant improvement in nasal airway resistance (P less than 0.01) after maxillary superior movement. This rather unexpected finding can be explained by examining the effect of maxillary superior movement on the nasal valve area in the anterior nose. The nasal valve area is a teardrop-shaped area bordered by the nasal septum, the caudal end of the upper lateral nasal cartilage, the floor of the nose, and the soft fibrofatty tissue on the lateral aspect of the nose. The apex of the teardrop-shaped area (the angle between the nasal septum and the upper lateral cartilage) is called the nasal valve. In the Caucasian type of nose, the nasal valve accounts for most of the inspiratory resistance to airflow. Maxillary superior movement increases the alar width. It is proposed that this increase in alar width is transmitted at least partially to the nasal valve angle, causing it to widen slightly, paradoxically reducing nasal airway resistance while reducing skeletal intranasal dimensions.