Objective: To evaluate the safety and effectiveness of coupling an active middle ear implant to the short process of the incus in subjects with meatal pathologies.
Study design: Retrospective study.
Setting: Tertiary referral center.
Patients: Twelve patients suffering from either congenital aural atresia or acquired meatal fibrosis.
Intervention: Implantation of an active middle ear implant with coupling of the actuator to the short process of the incus.
Main outcome measures: Evaluation of the air conduction and bone conduction hearing thresholds pre- and postoperatively, aided warble-tone hearing thresholds, unaided and aided speech recognition in quiet and noise. Questionnaires on subjective benefit and quality of life.
Results: Mean unaided postoperative air conduction and bone conduction thresholds did not vary significantly from preoperative values (p = 0.55 and 0.082, respectively). The mean functional gain amounted to 42.1 ± 8.8 dB, the mean aided sound field threshold of the implanted ear was 28.6 ± 8.6 dB. No significant difference in functional gain but a close to significant difference in postoperative aided thresholds (p = 0.053) were found between subjects with congenital atresia and acquired fibrosis. Subjective benefit assessed by the global score of the Abbreviated Profile of Hearing Aid Benefit questionnaire revealed an improvement of 31 to 42%.
Conclusion: Coupling of the actuator to the short process of the incus is a safe and clinically promising procedure in cases where the standard application to the long process is not feasible. In pure conductive hearing loss the benefit is comparable to long incus process coupling, whereas in mixed hearing loss slightly worse results were observed.