Round window stimulation for conductive and mixed hearing loss.

OBJECTIVE: Assess surgical complications, postoperative residual hearing, and speech perception outcomes of placement of a middle ear implant on the round window in conductive and mixed hearing loss cases. STUDY DESIGN: Single-subject, repeated-measures design where each subject served as his or her own control. SETTING: Tertiary referral medical systems. SUBJECTS: Eighteen subjects with either conductive or mixed hearing loss who could not benefit from conventional amplification were enrolled in a clinical trial investigating vibratory stimulation of the round window. INTERVENTION: The floating mass transducer (FMT) was positioned in the round window niche. MAIN OUTCOME MEASURES: Unaided residual hearing, and aided sound field thresholds and speech perception abilities were evaluated preoperatively, and at 1, 3, 6, and 10 months post-activation of the external speech processor. RESULTS: Six subjects experienced complications that either required further medical management or resolved on their own. There was no difference in residual bone conduction thresholds or unaided word discrimination over time. All subjects experienced a significant improvement in aided speech perception abilities as compared to preoperative performance. CONCLUSION: Subjects with conductive and mixed hearing loss with placement of the FMT in the round window niche experienced improved sound field thresholds and speech perception, without compromising residual hearing thresholds. Vibratory stimulation of the round window via a middle ear implant may be an appropriate treatment option for patients with conductive and mixed hearing loss. Additional research is needed on the preferred placement of the FMT, improvement of functional gain, and methods to limit postoperative complications and need for revision surgery.

MRI information for commonly used otologic implants: review and update.

OBJECTIVE: To review information on magnetic resonance imaging (MRI) issues for commonly used otologic implants. DATA SOURCES: Manufacturing companies, National Library of Medicine's online database, and an additional online database (www.MRIsafety.com). REVIEW METHODS: A literature review of the National Library of Medicine's online database with focus on MRI issues for otologic implants was performed. The MRI information on implants provided by manufacturers was reviewed. RESULTS: Baha and Ponto Pro osseointegrated implants' abutment and fixture and the implanted magnet of the Sophono Alpha 1 and 2 abutment-free systems are approved for 3-Tesla magnetic resonance (MR) systems. The external processors of these devices are MR Unsafe. Of the implants tested, middle ear ossicular prostheses, including stapes prostheses, except for the 1987 McGee prosthesis, are MR Conditional for 1.5-Tesla (and many are approved for 3-Tesla) MR systems. Cochlear implants with removable magnets are approved for patients undergoing MRI at 1.5 Tesla after magnet removal. The MED-EL PULSAR, SONATA, CONCERT, and CONCERT PIN cochlear implants can be used in patients undergoing MRI at 1.5 Tesla with application of a protective bandage. The MED-EL COMBI 40+ can be used in 0.2-Tesla MR systems. Implants made from nonmagnetic and nonconducting materials are MR Safe. CONCLUSION: Knowledge of MRI guidelines for commonly used otologic implants is important. Guidelines on MRI issues approved by the US Food and Drug Administration are not always the same compared with other parts of the world. IMPLICATIONS FOR PRACTICE: This monograph provides a current reference for physicians on MRI issues for commonly used otologic implants.