The contribution of selective dysventilation to attical middle ear pathology.

Epitympanic primary cholesteatoma represents a challenge for ENT surgeons. Its exact pathogenesis is still unknown because of the very complex anatomy of this region. Until now, only a few authors have described this region and tried to hypothesize the causes that could lead to cholesteatoma genesis. We hypothesize the existence of a selective dysventilation of the epitympanic region based on the presence of various mucosal folds occluding air ventilation from the middle ear to the epitympanum, through the epitympanic isthmus, causing a negative epitympanic pressure and consequently cholesteatoma formation. All the anatomic findings were obtained with the aid of 0° and 45° angled surgical endoscopes. From our findings, patients affected by an epitympanic cholesteatoma often have a total isthmus blockage that completely isolates the whole epitympanum from the middle ear, causing a deficit of oxygenation of the mucosa that normally should be guaranteed by the Eustachian tube and which always works physiologically in these patients. This is confirmed by the tympanogram test where we observed how the pressure at the level of the tympanic cavity was normal, whereas the epitympanic pressure was selectively negative. In conclusion, selective epitympanic dysventilation syndrome consists of the concomitant presence of a series of complete or incomplete epitympanic diaphragms and ME isthmus blockage causing negative epitympanic pressure, and leading to the formation of a retraction pocket or cholesteatoma associated with normal Eustachian tube function.