Ostial resistance. Its variations and correlations to the patency test results.

Resistance measurement is a simple and practical mean of testing ostial function. The present study showed that the results of measuring the ostial resistance varied according to the amount of antral secretion. For that reason the postirrigational mean resistance is about 1/5 of the highest mean resistance in acute maxillary sinusitis. The average ostial resistance in healthy persons is 2.5 cm of water and in acute maxillary sinusitis at diagnostic puncture, 13.0 cm of water, and at the end of treatment, 3.3 cm of water. There are discrepancies between the results of resistance measuring and patency tests in 10-30% of cases. It is difficult to say whether these are due more to faults in the measuring techniques of the resistance or the patency. As an ostial function test, resistance measuring is quantitative and the testing of patency qualitative.