Background: It is well known that Eustachian Tube (ET) plays a crucial role in maintaining middle ear aeration and atmospheric pressure. Usually inflammatory middle ear chronic disease is related to ET dysfunction due to poor tympanic ventilation. Although middle ear aeration is certainly related to ET function, other anatomic factors play an important role in ventilation of these spaces. Actually epitympanum aeration is strictly dependent to the ventilation pathways; if the tensor fold and the lateral incudo-malleal fold are complete the only ventilation pathway to the epitympanum is through the tympanic isthmus. In such cases when an isthmus blockage occurs the ventilation of epitympanum may be impaired and the only gas exchange would comes from the mucosa of mastoid cells. This scenario describe a selective epitympanic disventilative syndrome, possibly not related to ET impairment.

With introduction of the endoscope in middle ear surgery, anatomy of middle ear spaces has become wider and clearer due to a better magnification and to the possibility to look “behind the corner” and to better understand the ventilation pathways, particularly in patients with retraction pockets.

Materials and methods: From December 2008 to December 2015, 470 tympanoplasty were performed with exclusive endoscopic approach; All patients candidate to ear surgery underwent to high resolution CT-scan, audiometric and impedenzometric evaluations. Inclusion criteria in our study were patients affected by not-self cleansing attic retraction pocket. Subjects affected by a disease of the epitympanic compartments (not self cleansing retraction pockets of the attic; epitympanic cholesteatoma) and with type A tympanogram were included in present study.

Exclusion criteria: subjects affected by a disease involving the protympanic, the mesotympanic and the retrotympanic region, or patients who previously underwent middle ear surgery.