[Clinical views of cases with discontinuity of the ossicular chain]

It is well known that reconstruction for discontinuity of the ossicular chain, without inflammatory disease, has a good prognosis. Eleven cases of congenital ossicular chain malformation without ossicular fixation and 6 cases of ossicular chain injury due to the head trauma or an earpick , were treated surgically. The method of reconstruction and the prognoses, according to short-term and long-term follow up, were studied in these 17 cases. The following results were obtained: 1) In almost all cases, the pure tone audiograms were flat or slightly rising types, and the mean air conductive hearing loss was about 60 dB. Only 2 cases showed the falling type with conductive hearing loss. Connective tissue was observed at the incudo-stapedial joint intraoperatively in these two cases. 2) Mean hearing improvement was in 31.8 dB in the low frequency region (125, 250, 500 Hz), 22.7 dB in the middle frequency region (500, 1000, 2000 Hz), and 12.9 dB in the high frequency region (2000, 4000, 8000 Hz), within 3 weeks after operation, in all 17 cases. 3) No clear changes in hearing level were seen postoperatively, for the four periods evaluated; 1-3 weeks, 1-3 months, 4-6 months and over 7 months in all cases. 4) The cases in whom the reconstruction was performed between the incus and stapes, especially the foot plate of the stapes, showed poor hearing recovery. 5) There was no relation between hearing recovery and the prostheses used in reconstructions. However, it was thought that pieces of the patient's own cartilage or bone should be used whenever possible.