External nasal valve collapse - a case-control and interventional study employing a novel internal nasal dilator (Nasanita).

BACKGROUND: Nasal alar collapse is a common problem and difficult to assess and treat.

METHODS: In 10 healthy controls and 10 patients with alar collapse, the size of the external nasal valve was analyzed on standardized nasal base photographs during quiet breathing and forced inspiration. A novel internal nasal dilator (Nasanita, Siemens & Co, Germany) was employed to assess the effects of a therapeutic intervention. In addition, active anterior rhinomanometry was performed.

RESULTS: During quiet breathing, the external nasal valves were significantly smaller in patients with alar collapse (0.3 +/- 0.08 cm2) than in controls (0.7 +/- 0.2 cm2; p < 0.001). In heal-thy controls, forced inspiration did not significantly alter the size of the external nasal valve (-1.8% +/- 27.5%; p = 0.84), whereas it significantly decreased the external valve area in patients with alar collapse (-42.1% +/- 26.4%; p = 0.001). The internal nasal dilator significantly increased external valve areas during quiet breathing and forced inspiration and completely abolished alar collapse. Nasal airflow at a transnasal pressure difference of 150 Pa was not correlated with external valve size. Nasal airflow increased significantly after inserting the internal nasal dilator to 1300 +/- 370 ml/s (p < 0.001) in controls and 1300 +/-300 ml/s (p < 0.01) in patients.

CONCLUSION: A small sized external nasal valve appears to be a major causative factor of alar collapse. A novel internal nasal dilator effectively enlarged the external nasal valve, abolished alar collapse and improved nasal airflow.