The airway resistance of the naso-frontal duct during and after acute frontal sinusitis. A long term follow-up of 49 trephined frontal sinuses

A new pressure flow method for function tests and calculation of the airway resistance in the naso-frontal duct is presented. With this pressure flow technique the function and airway resistance of the naso-frontal duct was tested in 49 patients who were trephined for acute frontal sinusitis. The tests were performed during the primary healing period (0-16 days) and in a long term study 2, 6 and 12 months after operation. The patients were also checked radiologically and clinically. A prolonged healing period (more than 6 days) corresponded significantly to a high incidence of recurrent disease. With this method it is possible to define groups where recurrences might be expected because of impaired function of the naso-frontal duct.