Active Middle Ear Implants in Patients Undergoing Subtotal Petrosectomy: Long-Term Follow-up

Objective In 2009, we had introduced the active middle ear implant (aMEI) round window coupling in patients undergoing a subtotal petrosectomy and reported our first results. In the current study, we evaluated the long-term firmness of the vibranting floating mass transducer (FMT) within the round window niche, the long-term audiologic results and the patient's perspective of wearing the speech processor over time. Patients and Intervention Of 10 patients, 6 female and 1 male patients (age range from 30 to 71 yr) had undergone subtotal petrosectomy with aMEI round window vibroplasty and were available for a long-term follow-up. Indications were recurrent or chronic ear infections with preserved inner ear function and inability for ossicular chain reconstruction. A thin piece of fascia was placed between the FMT and the round window membrane once the round window niche had been enlarged by drilling. The operative cavity was filled with fat and a muscle flap in all cases. Main Outcome Measures Audiologic evaluations included pre- and postoperative pure-tone audiometry, Freiburger syllable and numeric tests. All patients underwent preoperative computed tomographic (CT) scans and magnetic resonance imaging (MRI) examination. Postoperative follow-up included CT scans at 1 and preferentially 3 to 5 years to confirm the correct positioning of the FMT and the complete removal of the underlaying pathology. Subjective benefit was rated by the Glasgow Hearing Aid Benefit Profile. Results There were no immediate postoperative complications. CT scans confirmed the correct and durable positioning of the FMT. Audiometric tests revealed a stable and adequate functional gain in all patients with limited adjustments over time. Subjective rating reached a high satisfaction score, and all patients remained long-term implant users. One patient developed a skin necrosis over the implant because of excessive pressure exerted by the retaining magnet of the headpiece. Revision was performed using local skin flaps with preservation of the functioning implant. Conclusion Our radiologic, audiometric, and subjective data show stable long-term results of round window vibroplasty in patients undergoing subtotal petrosectomy, and we continue to recommend this treatment option instead of another mastoid revision procedure.