The relationship of middle meatus polyps and development of the middle conchas CT study

Objective: To study the relationship between polyps of middle meatus and the position of the inferior border of the middle concha related to the semilunar hiatus, and to evaluate the diagnostic value of coronal CT scan of the nasal cavity after ephedrine spray by means of comparison of CT images and clinical findings. Methods: The coronal CT studies of 102 cases clinically suspected as sinusitis and/or nasal polyps were included in this study. 1% ephedrine was sprayed in nasal cavity of the patients before CT study and the patient were asked to take supine position with head over extended over 5 minutes. Axial and coronal CT scan was taken with supine position, 2 mm slice thickness and high resolution reconstruction. Observation was focused on contraction of the nasal mucosa and soft-tissue mass of the middle meatus (polyps). The middle concha was divided into 3 types according the position of its inferior border related to the semilunar hiatus: superior-hiatus type (the inferior border of the middle concha superior to the semilunar hiatus), hiatus type (the inferior edge of the middle concha at the level of the semilunar hiatus), inferior-hiatus type (the inferior edge of the middle concha inferior to the semilunar hiatus). Statistic comparing the occurrence of the middle meatus polyps with different middle conchas type and measuring the length of the middle conchas of inferior-hiatus type from the level of the semilunar hiatus to the inferior border were performed. Results: Good and better contraction of the nasal mucosa with clear manifestation of the lesion was seen in 98 of 102 cases. Nasal polyps of middle meatus were diagnosed in 71 sides of nasal cavities of 47 cases and confirmed surgically and/or clinically. 39 superior-hiatus and hiatus middle conchas were found ipsilateral to the polyps (54.9%). Of 204 sides of 102 cases, superior-hiatus type middle conchas was found in 18 sides of nasal cavity with middle meatus polyps in 11 sides (61.1%); hiatus type in 38 sides with middle meatus polyps in 28 sides (73.7%); and inferior-hiatus type in 148 sides with middle meatus polyps in 32 sides (21.6%). The difference was markedly significant statistically. Conclusion: Coronal CT scan after ephedrine spray into the nasal cavity can depict the mass in the nasal cavity better, especially nasal polyps with swollen mucosa. The method is simple and easy to perform. The poorly developed middle concha and the exposed middle meatus may be one of the cause of polyps of middle meatus. It clues on that the middle concha should be preserved as much as possible during the endoscopic sinus surgery, opening the ethmoidal infundibulum and bullas, to decrease post operative recurrence of middle meatus polyps