Learning Objectives: Use of Codacs

Objective: Implantable hearing aids have become a valid option for the therapy of various forms of hearing loss. Codacs Direct Acoustic Cochlear Implant System is the first vibratory implant available for patients with MHL. By directly coupling sound energy into the perilymph, a very high maximum power output (MPO) is achieved over a broad frequency range. Via a conventional stapedotomy, the vibratory energy of the electromagnetic actuator is transferred directly to the perilymph through the oval window.

Patients and Methods: Patients with different etiologies of MHL were implanted:

Otosclerosis: n = 29

Tympanosclerosis: n = 4 (1 with subtotal petrosectomy)

Chronic otitis media: n = 15 (12 with subtotal petrosectomy)

In cases with intact posterior canal wall the implantation was done through the posterior tympanotomy. Stapes footplate was perforated and the stapes prosthesis was fixed at the long process of the incus. In cases with canal wall down and chronic otitis media there was a two-step procedure with subtotal petrosectomy and optimal fat obliteration followed by Codacs implantation six month afterwards. Pre- and postoperative bone and air conduction thresholds and word recognition scores were recorded preoperatively with fitted hearing aid (only 32 of the reported patients were able to use a hearing aid before implantation or subtotal petrosectomy) and postoperatively over time.

Results: Bone conduction thresholds showed no significant change over all in the implanted group. In few patients with mobile footplate some loss of bone conduction was observed. The mean free field thresholds were 43 +/−7 dB (0.5–4 kHz) and the monosyllabic word score was 67 % at 65 dB presentation level compared to conventional hearing aids with 24 %. Speech intelligibility in noise was 2.1 dB SNR in the OLSA Matrix test (S0N0) three month after activation.

Conclusion: Codacs provides an effective treatment for patients with MHL.