Middle ear injury through the external auditory canal: a review of 44 cases

We performed a retrospective review of 44 patients with middle ear injury incurred through the external auditory canal. Twenty-two of the 44 patients had presented to our center within 1 month of their injury (early group), and 22 presented later (delayed group); the mean interval from the time of the trauma to presentation was 6 days in the early group and 7 years in the delayed group. The causes of injury were penetrating trauma (70% of cases), thermal insults (20%), and explosive and nonexplosive blasts (9%). Purulent otorrhea, cholesteatoma, and ossicular discontinuity were more common in the delayed group. Otologic surgery was required in 9 early-group patients (41%) and in all 22 delayed-group patients (100%). Two patients in the early group developed a dead ear. The mean pure-tone averages (PTAs) at presentation were 30.7 and 52.2 dB in the early and delayed groups, respectively; after management, the corresponding mean PTAs were 21.0 and 42.5 dB. The respective mean air-bone gaps in the two groups were 14.6 and 28.2 dB at presentation and 8.0 and 17.2 dB after management. We conclude that middle ear injury incurred as a result of trauma sustained through the external auditory canal is associated with considerable morbidity. Patients who present in a delayed fashion have significantly poorer hearing at presentation and after management. Patients who do not develop a dead ear generally derive benefit from reconstruction of the middle ear sound-conduction mechanism.