Management of Severe Cochlear Implant Infections—35 Years Clinical Experience

Objective: Infectious complications occurring in cochlear implant (CI) recipients is of potentially major impact. A better understanding of severe infections in this cohort is necessary. Design: Single-center, retrospective cohort study. Level of Evidence 2B. Setting: Single-center, retrospective cohort study at a tertiary referral hospital. Participants and interventions: We included all patients who received a CI at our institution between 1983 and end of 2018 (4,622 implantations). Main Outcomes: Prevalence, incidence, risk factors, and functional outcomes in severe implant infections. Results: There was an overall prevalence of 0.65% of severe CI infections. The cumulative incidence decreased after the year 2000, with lower infection rates with newer implant models. Patients with local risk factors were more susceptible to implant infection. In most patients, delayed re-implantation was successful. Speech-perception after re-implantation was comparable to pre-revision performance. Conclusions: Modified implant design and improved surgical technique has led to a decrease in the prevalence and incidence of infected implants. In severe implant infections, active surgical and antimicrobial management is required, to achieve good long-term results

Toward a Better Understanding of Electrocochleography: Analysis of Real-Time Recordings.

OBJECTIVES Real-time electrocochleography (ECochG) has been used as a monitoring tool during cochlear implantation (CI), whereby, amplitude drops have been correlated with postoperative acoustic hearing results. However, no consensus has been reached as to how a single event of an amplitude drop should be characterized. The aim of this study was to identify ECochG events that predict loss of hearing 1 month after surgery. DESIGN Fifty-five patients were included in this prospective cohort study. Real-time ECochG measurements were performed during CI electrode insertion. Single ECochG events were characterized according to their amplitude loss and slope steepness. RESULTS Using receiver operating characteristic analyses, the most efficient cut-off criterion for a relative hearing loss of 25% was an amplitude loss of 61% at a fixed slope steepness of 0.2 µV/sec. Three-quarters of our population had at least one such event during implantation. Most events occurred shortly before full insertion. With increasing number of events, median residual hearing thresholds deteriorated for all frequencies. Larger amplitude drops trended toward worse hearing preservation. Signal recovery after an ECochG event could not be correlated to acoustic hearing outcomes. CONCLUSIONS Our data suggest that amplitude drops exceeding 61% of the ongoing signal at a slope steepness of 0.2 µV/sec are correlated with worse acoustic hearing preservation. Clearly defined ECochG events have the potential to guide surgeons during CI in the future. This is essential if a fully automated data analysis is to be employed or benchmarking undertaken

Real Time Monitoring During Cochlear Implantation: Increasing the Accuracy of Predicting Residual Hearing Outcomes.

OBJECTIVES Real-time electrocochleography (rt-ECochG) is a method to detect intracochlear potential changes during cochlear implantation (CI). Steep amplitude drops of the cochlear microphonic (CM) signal (so called "ECochG events") have been correlated with worse residual hearing outcomes. However, the sensitivity and specificity of monitoring CM amplitude on its own are too low to use it as a biomarker. The aim of this article was to establish if additional signal components would help to better predict postoperative hearing outcomes. DESIGN AND SETTING Single-center, prospective cohort study at a tertiary referral hospital. PARTICIPANTS AND INTERVENTIONS Between 2017 and 2020, we included 73 adult patients receiving a lateral wall cochlear implant electrode. During electrode insertion, rt-ECochG measurements were performed. MAIN OUTCOMES We calculated a multiple regression analysis for patients with one ECochG event. The dependant variable was the relative acoustic hearing result 4 weeks after surgery. Independent variables were CM latency, a ratio of the auditory nerve neurophonic to the CM (the ANN/CM index) as well as CM signal recovery. RESULTS The change of the ANN/CM index linearly correlated with acoustic hearing outcomes 4 weeks after surgery. Adding this factor led to a statistically significant increase in the variance accounted for by the regression model. CONCLUSIONS When monitoring the implantation process with rt-ECochG, prediction of postoperative hearing thresholds is improved by addition of the ANN/CM index to a model that includes CM amplitude fluctuation

Trans-mastoid plugging of superior semicircular canal dehiscence: long-term follow-up.

OBJECTIVE To evaluate the long-term outcomes of trans-mastoid plugging of superior semicircular canal dehiscence (SSCD), focusing on complicated cases. METHODS In this cohort study, we included all patients who underwent trans-mastoid plugging of SSCD between 2009 and 2019. We evaluated the symptoms (autophony, sound-/pressure-induced vertigo, disequilibrium, aural fullness and pulsatile tinnitus) before and 1 year after surgery in the medical records. We systematically assessed the current symptoms 6.2 ± 3 years postoperative (range 2.2-12.3 years) using questionnaires sent by post and validated by telephone interviews. We also documented any complications and the need for further procedures. We compared pure tone and speech audiometry before and 1 year after surgery. Finally, the degree of mastoid pneumatisation and mastoid tegmen anatomy were reviewed on preoperative CT scans. RESULTS We included 24 ears in 23 patients. No complications were recorded, and none required a second procedure for SSCD. Following surgery, oscillopsia and Tullio phenomena resolved in all patients. Hyperacusis, autophony, and aural fullness were also settled in all patients except one. Balance impairment persisted to some degree in 35% of patients. No deterioration over the years was reported regarding the above symptoms. On average, bone conduction pure tone average pre- and 1 year postoperative were 13.7 ± 17 and 20.5 ± 18 dB, respectively (P = 0.002). Air bone gaps were reduced from 12.7 ± 8 to 5.9 ± 6 (P = 0.001). Two patients had a significant sclerotic mastoid, three had a prominent low-lying mastoid tegmen, and two had both. Anatomy had no effect on outcome. CONCLUSION Trans-mastoid plugging of SSCD is a reliable and effective technique which achieves long-lasting symptom control, even in cases with sclerotic mastoid or low-lying mastoid tegmen

Real Time Monitoring During Cochlear Implantation

OBJECTIVES Real-time electrocochleography (rt-ECochG) is a method to detect intracochlear potential changes during cochlear implantation (CI). Steep amplitude drops of the cochlear microphonic (CM) signal (so called "ECochG events") have been correlated with worse residual hearing outcomes. However, the sensitivity and specificity of monitoring CM amplitude on its own are too low to use it as a biomarker. The aim of this article was to establish if additional signal components would help to better predict postoperative hearing outcomes. DESIGN AND SETTING Single-center, prospective cohort study at a tertiary referral hospital. PARTICIPANTS AND INTERVENTIONS Between 2017 and 2020, we included 73 adult patients receiving a lateral wall cochlear implant electrode. During electrode insertion, rt-ECochG measurements were performed. MAIN OUTCOMES We calculated a multiple regression analysis for patients with one ECochG event. The dependant variable was the relative acoustic hearing result 4 weeks after surgery. Independent variables were CM latency, a ratio of the auditory nerve neurophonic to the CM (the ANN/CM index) as well as CM signal recovery. RESULTS The change of the ANN/CM index linearly correlated with acoustic hearing outcomes 4 weeks after surgery. Adding this factor led to a statistically significant increase in the variance accounted for by the regression model. CONCLUSIONS When monitoring the implantation process with rt-ECochG, prediction of postoperative hearing thresholds is improved by addition of the ANN/CM index to a model that includes CM amplitude fluctuation

The Importance of Intraoperative Plain Radiographs during Cochlear Implant Surgery in Patients with Normal Anatomy

Although malpositioning of the cochlear implant (CI) electrode array is rare in patients with normal anatomy, when occurring it may result in reduced hearing outcome. In addition to intraoperative electrophysiologic tests, imaging is an important modality to assess correct electrode array placement. The purpose of this report was to assess the incidence and describe cases in which intraoperative plain radiographs detected a malpositioned array. Intraoperative anti-Stenver’s view plain X-rays are conducted routinely in all CI surgeries in our tertiary center before awakening the patient and breaking the sterile field. Data of patients undergoing 399 CI surgeries were retrospectively analyzed. A total of 355 had normal inner ear and temporal bone anatomy. Patients with intra or extracochlear malpositioned electrode arrays demonstrated in the intraoperative X-ray were described. There were four cases of electrode array malposition out of 355 implantations with normal anatomy (1.1%): two tip fold-overs, one extracochlear placement and one partial insertion. All electrodes were reinserted immediately; repeated radiographs were normal and the patients achieved good hearing function. Intraoperative plain anti-Stenver’s view X-rays are valuable to confirm electrode array location, allowing correction before the conclusion of surgery. These radiographs are cheaper, faster, and emit much less radiation than other imaging options, making them a viable cost-effective tool in patients with normal anatomy

Slim, Modiolar Cochlear Implant Electrode: Melbourne Experience and Comparison With the Contour Perimodiolar Electrode.

OBJECTIVE To describe the tip fold over rate, scalar localization, and speech perception outcomes of the CI532 Slim Modiolar Electrode. PATIENTS AND INTERVENTION All patients receiving the CI532 implant before June 2018. MAIN OUTCOME MEASURES Outcome measures for adults patients include pre- and postoperative speech perception, operative report details, electrode position as determined by X-ray and cone beam computed tomography. Comparison made with previous experience with the Contour perimodiolar electrode (CI512). In the pediatric population tip fold-over rate, measured by intraoperative X-ray, was the exclusive outcome. RESULTS One hundred twenty-five CI532 devices were implanted in adults and 69 in children. Electrode tip fold-over occurred in eight adults cases and none among children (4.1%). Cone beam CT scans of 120 out of 125 adult patients confirmed scala tympani (ST) position in all but one case where the electrode had been placed into scala vestibuli. There were no translocations from ST to scala vestibuli. This compares favorably with the CI512 translocation rate of 17%. Speech perception outcomes demonstrated good performance with mean preop phoneme scores of 16.2% (±13) increasing to 64.2% (±14) and 71.6 (±16) 3 and 12-months postop, respectively. Compared with a matched group of CI512 recipients, CI532 recipient phoneme scores were significantly higher 3 and 12-months postop by 4 and 7%, respectively. CONCLUSION The slim modiolar, CI532 electrode has provided very reliable ST position with a low rate of tip fold over. A trend toward better speech perception scores in CI532 compared with CI512 was observed

Electrical Impedance as a Biomarker for Inner Ear Pathology Following Lateral Wall and Peri-modiolar Cochlear Implantation.

OBJECTIVES/HYPOTHESIS Spikes in cochlear implant impedance are associated with inner ear pathology after implantation. Here, we correlate these spikes with episodes of hearing loss and/or vertigo, with a comparison between lateral wall and peri-modiolar electrode arrays. METHODS Seven hundred seventy recipients of Cochlear's slim-straight, lateral wall electrode (CI422), or peri-modiolar (CI512) electrode were investigated for impedance spikes. Impedance fluctuations were defined as a median rise of ≥ 4 kΩ across all intracochlear electrodes from baseline measurements taken 2 weeks after switch-on. Medical records were analyzed from 189 of the 770 patients. RESULTS The slim straight, lateral wall electrode was found to spike in impedance at a significantly higher rate than the peri-modiolar array (17% vs 12%). The peri-modiolar electrode tended to spike in impedance earlier than the slim-straight electrode. Impedance spikes were found to significantly correlate with medical events (hearing loss, vertigo, or tinnitus). Overall, in the "spike" group, 42 of 75 patients (56%) demonstrated a clinical event during the impedance spike, whereas 26 of 114 patients (22%) of the "non-spike" group had a clinical event. This significant difference existed with both implant types. CONCLUSION These results demonstrate a small, but significant increase in impedance spikes in lateral wall electrodes, and support the relationship between spikes in cochlear implant impedances and postoperative inner-ear events, including the loss of residual hearing and vertigo. Monitoring cochlear implant impedance may be a method for early detection, and so the prevention, of these events in the future