Clinical results of percutaneous implants in the temporal bone.

The bone-anchored hearing aid is an alternative to the conventional bone-conduction hearing aid, without the disadvantages of pressure pain or skin irritation and with direct sound transmission to the skull. The bone-anchored hearing aid is coupled to a percutaneous titanium implant, which is placed in the mastoid process in two surgical stages. We analyzed the clinical results of 68 percutaneous implants in 65 patients. After a follow-up period of 8 to 45 months, 97% of the implants were anchored in the bone. In 86% of the implants, no potentially dangerous skin reactions occurred. The occurrence of skin reactions was not time dependent. Movement of the skin, thick skin, and poor skin condition around the implant were related to the onset of skin reactions. This study showed that the percutaneous titanium implant forms a stable link between the bone-anchored hearing aid and the skull.

The super-bass bone-anchored hearing aid compared to conventional hearing aids. Audiological results and the patients' opinions.

Twelve patients with severe mixed hearing loss (PTA ranging from 70 to 108 dB HL) were provided with the percutaneous 'super-bass HC 220' bone-anchored hearing aid (BAHA) to replace their former hearing aid. Five had previously worn an air-conduction hearing aid (behind-the-ear type, BTE) which could no longer be used because of recurrent otorrhoea; the others had previously worn a conventional (transcutaneous) bone-conduction hearing aid (CBHA) which had caused serious complaints, such as headaches or skin irritation. Free-field speech audiometry in the subgroup of patients who used to wear a CBHA revealed that the maximum intelligibility score with the BAHA was equal to or better than that obtained with the CBHA (range from 0 to +27%). In three of the five patients who used to wear a BTE, the speech scores were poorer with the BAHA than with the BTE (range from -13 to -40%). For the remaining two patients, the difference in scores was 0 and +10%. In conclusion, speech recognition with the BAHA HC220 in the patients with severe mixed hearing loss was comparable to, or better than, that with a CBHA. Compared to an air-conduction hearing aid, the results may be considerably poorer. The results of the questionnaire were in good agreement with the measurements and support the conclusions.