[Cause analysis of non dry ear after canal wall down mastoidectomy].

To investigate the possible causes of non dry ear after canal wall down mastoidectomy(CWD).Clinical data of 42 patients undergoing revision CWD in our hospital were analyzed retrospectively,which included history,symptoms,signs,audiological examination,imaging examination, intraoperative findings and postoperative follow-up.All patients underwent CWD and tympanoplasty under general anesthesia.Twenty-six cases were insufficient opened of sinodural angle,36 cases remained mastoid air cell(9 cases is mastoid tip air cell remained),13 cases were inadequate exposured of anterior epitympanic recess, 23 cases were inadequate exposured of posterior tympanum, 25 cases had high facial ridge, posterior facial nerve and labyrinth air cell were 5 cases,3 cases had granulation in round window, 5 cases had dysfunctional eustachian tube, 32 cases had narrow external acoustic meatus. During 3 months,6 months and 1 year follow-up, all 42 cases patients under revision CWD presented with dry ears.Insufficient opened of sinodural angle and mastoid air cell,inadequate exposured of anterior epitympanic recess and posterior tympanum, high facial ridge, narrow external acoustic meatus are all the possible causes of no-dry ear after CWD; As the location of concealment, posterior facial nerve and labyrinth air cell are difficult to clean. The dressing cavity do not be cleaned in time after operation is also the underlying cause of postoperative non-dry ear.