Management of far advanced otosclerosis in the era of cochlear implantation.

OBJECTIVE: To evaluate issues pertaining to cochlear implantation in patients with far advanced cochlear otosclerosis. STUDY DESIGN: Prospective cohort. SETTING: Tertiary care referral center. PATIENTS: Eight adult patients (18 years of age or older) referred for management of profound hearing loss, the cause of which was determined to be otosclerosis. INTERVENTION: Cochlear implantation with multichannel cochlear implant device. MAIN OUTCOME MEASURES: Benefit from cochlear implant as measured by CID sentence scores, incidence and management of facial nerve stimulation, and technical issues pertaining to cochlear implantation in this patient population. RESULTS: All patients demonstrated significant improvement in auditory function as measured by performance on CID sentence scores and ability to engage in telephone conversation. Facial nerve stimulation was present in two of eight patients and was managed with deactivation of the stimulating electrodes. Ossification in the basal turn of the cochlea, detected on preoperative computed tomography, necessitated placement of the electrode into the scala vestibuli in two patients and use of a thinner electrode (Nucleus 24) in a third patient. CONCLUSION: Patients with profound hearing loss secondary to otosclerosis derive excellent benefits from cochlear implantation. Surgical implantation may be complicated by ossification of the cochlea, which can be detected on preoperative computed tomography. Electrode activation may be complicated by facial nerve stimulation, which can be addressed with programming strategies.

Tinnitus suppression in patients with cochlear implants.

OBJECTIVE: To determine the degree of tinnitus suppression provided by currently available multichannel cochlear implants and to determine factors that can influence this process. STUDY DESIGN: Prospective cohort. SETTING: Tertiary-care referral center. PATIENTS: Thirty-eight adult patients (18 years of age or older) with severe-to-profound hearing loss and tinnitus who met criteria for cochlear implantation. INTERVENTION: Cochlear implantation with a multichannel cochlear implant device. MAIN OUTCOME MEASURES: Patients rated the intensity of their tinnitus using a semiquantitative scale before and after cochlear implantation. These data were analyzed to determine the significance of the reduction of tinnitus after implantation. Tinnitus levels after implantation were also analyzed to determine whether the level of speech recognition, patient gender, or the implant type influenced the degree of tinnitus reduction. RESULTS: Statistical analysis revealed a significant reduction in tinnitus intensity in patients using cochlear implants, with 35 of 38 patients (92%) experiencing a reduction in tinnitus intensity. All multichannel implants studied afforded similar degrees of tinnitus suppression. The degree of tinnitus reduction was not correlated with speech recognition, as measured by CID Everyday Sentence scores. Female patients had significantly greater degrees of tinnitus before implantation, but both male and female patients demonstrated similar levels of tinnitus after implantation. No patient experienced greater levels of tinnitus after implantation. CONCLUSION: All currently available multichannel cochlear implant devices provide effective and similar levels of tinnitus suppression when activated. Exacerbation of tinnitus as a result of cochlear implantation does not represent a significant risk. The mechanisms by which cochlear implants exert tinnitus suppression are, as yet, unclear.

Facial nerve stimulation from cochlear implants.

OBJECTIVE: To evaluate the incidence of facial nerve stimulation from cochlear implants and to better define the segment of nerve being stimulated and the causes of stimulation. STUDY DESIGN: Retrospective patient case review and a temporal bone dissection study. SETTING: A tertiary care setting. PATIENTS: All patients given a cochlear implant at the Hospital of the University of Pennsylvania. This encompassed only adult patients. INTERVENTION: All patients had surgical insertion of either a 3M single channel, Nucleus 22-channel, or CLARION multichannel cochlear implant. MAIN OUTCOME MEASURES: Demonstration of facial nerve stimulation with a cochlear implant and determination of affected electrodes; measurement of electrode location and distances between the labyrinthine segment of the facial nerve and the cochlea in temporal bone dissections: and determination of the relationship between the labyrinthine facial nerve and the cochlea using computed tomography evaluation. RESULTS: The overall incidence of facial nerve stimulation using all three devices was 14% (8 of 58). Otosclerosis and otosyphilis appear to be predisposing conditions to stimulation. The mid-cochlear electrodes, located near the labyrinthine facial nerve, appear to cause stimulation of the VIIth nerve most commonly. Computed tomographic evaluation of the bone between the labyrinthine fallopian canal and the cochlea may provide some indication of potential facial nerve problems. CONCLUSION: Facial nerve stimulation from the use of cochlear implants is more prevalent in patients with otosclerosis and otosyphilis. The labyrinthine segment of the facial nerve is the most likely area being stimulated in most patients. Preoperative computed tomographic evaluation may be beneficial in determining the possibility of this problem.