The relationship between frontal sinusitis and localization of the frontal sinus outflow tract: a computer-assisted anatomical and clinical study.

OBJECTIVE To evaluate the relationship between frontal sinusitis and the localization of the frontal sinus outflow tract medial or lateral to the superior attachment of the uncinate process (UP). DESIGN A retrospective anatomical and clinical study. SETTING An ear, nose, and throat clinic in işli Etfal Teaching and Research Hospital, Istanbul, Turkey. PATIENTS Paranasal sinus computed tomographic scans of 486 sides of the frontal sinuses (hereafter referred to as sides) of 243 patients who had chronic sinusitis were evaluated. In 125 sides (26%), the superior attachment of the UP could not be identified. In the remaining 361 sides (74%), the prevalence of superior attachment of UP types and the presence of frontal sinusitis in each side were recorded. Localization of the frontal sinus outflow tract was determined according to the superior attachment of the UP. Drainage of the frontal sinus to the middle meatus (medial to the superior attachment of the UP [types 1-3]) was classified as group 1, and drainage of the frontal sinus to the ethmoid infundibulum (lateral to the superior attachment of the UP [types 4-6]) was classified as group 2. RESULTS Frontal sinusitis was found in 125 (35%) of 361 sides. The distribution of frontal sinusitis was 97 (41%) of 237 in group 1 and 28 (23%) of 124 in group 2. Group 1 drainage had a statistically significant presence of frontal sinusitis (chi(2) = 12.11; P<.001). The prevalence of superior attachment of UP types was 63% for type 1/2, 3% for type 3, 12% for type 4, 14% for type 5, and 8% for type 6. CONCLUSIONS Frontal sinus outflow tract, which is medial to the superior attachment of the UP, is more common than the lateral one. There is a statistically significant relation between the presence of frontal sinusitis and the frontal sinus outflow tract, which is medial to the superior attachment of the UP.