Cause of posterior canal wall retraction after surgery from the viewpoint of mastoid conditions.

Objective: To determine the relationship between preservation of the mastoid mucosa during ear surgery and retraction of the attic or posterior wall of the external auditory canal (EAC) and mastoid aeration after surgery.

Methods: Retraction of the posterior EAC wall and mastoid aeration were evaluated after surgery in 48 individuals (50 ears) with cholesteatoma, adhesive otitis media, or chronic suppurative otitis media, in whom the posterior bony EAC walls were removed with or without preservation of mucosa and reconstructed with soft tissues alone (EAC skin and temporal fascia) during surgery.

Results: Postoperative computed tomography showed that in ears with notable retraction of the posterior EAC wall appearing like an open mastoid cavity, there was no air in the mastoid, whereas in ears with no or only slight retraction there was computed tomographic evidence of mastoid aeration. Second, notable retraction of the posterior EAC wall occurred in a significantly smaller percentage of ears in which at least the epitympanic mucosa had been able to be preserved during surgery than in those that had undergone removal of all mucosa (mastoidectomy).

Conclusions: These results indicate that 1) preservation of epitympanic mucosa during surgery is an important factor for prevention of retraction of the posterior EAC wall and for reaeration of the mastoid after surgery, and 2) the intact canal wall technique seems to be indicated whenever at least the epitympanic mucosa can be preserved, and when no mucosa can be preserved the canal wall down procedure seems to be indicated.