Purpose: To evaluate the audiological effectiveness of Bonebridge implantation in patients with bilateral congenital malformation of the external and middle ear.
Methods: Twenty-eight cases [17 boys and 11 girls; median age, 12 years (range 8-36 years)] had unilateral Bonebridge implantation. Audiological tests were performed preoperatively and postoperatively, and included the pure-tone audiometry test, speech discrimination score (SDS), and evaluation of the unaided and aided hearing thresholds in sound fields. For the group of patients aged > 12 years, Mandarin Speech Test Materials were used to determine the SDS. For the other cases, the Mandarin Lexical Neighborhood Test was used. The daily life efficacy was assessed using the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire postoperatively. The t and t' tests were used in the statistical analyses.
Results: The hearing threshold with the Bonebridge improved by 25-35 dB HL, compared to that of the unaided condition. The SDS of patients aged > 12 years improved by about 50%; the SDS also improved by 10-20% in the three patients aged < 12 years. According to the APHAB, the mean Bonebridge scores of ease of communication, background noise, and reverberation decreased by 60.3 ± 15.7, 50.2 ± 11.1, and 59.4 ± 7.8, respectively, compared to the preoperative scores, and the Bonebridge score of aversiveness was higher (69.8 ± 10.8) than the unaided score.
Conclusions: The audiological effectiveness of the Bonebridge was significant and noticeable in bilateral congenital malformation of the external and middle ear. The Bonebridge can be an alternative and effective solution for those patients to improve hearing.
Keywords: Bilateral; Bone-conduction hearing aids; Bonebridge; Congenital malformation; External and middle ear; Transcutaneous bone-conduction implant.