[Technical advancements in cochlear implants : State of the art]

Comparison of 96-kV and 120-kV cone-beam CT for the assessment of cochlear implants

BACKGROUND

To compare the diagnostic value of 120-kV with conventional 96-kV Cone-Beam CT (CBCT) of the temporal bone after cochlear implant (CI) surgery.

METHODS

This retrospective study included CBCT scans after CI surgery between 06/17 and 01/18. CBCT allowed examinations with 96-kV or 120-kV; other parameters were the same. Two radiologists independently evaluated following criteria on 5-point Likert scales: osseous spiral lamina, inner and outer cochlear wall, semi-circular canals, mastoid trabecular structure, overall image quality, metal and motion artefacts, depiction of intracochlear electrode position and visualisation of single electrode contacts. Effective radiation dose was assessed.

RESULTS

Seventy-five patients (females, n = 39 [52.0%], mean age, 55.8 ± 16.5 years) were scanned with 96-kV (n = 32, 42.7%) and 120-kV (n = 43, 57.3%) protocols including CI models from three vendors (vendor A n = 7; vendor B n = 43; vendor C n = 25). Overall image quality, depiction of anatomical structures, and electrode position were rated significantly better in 120-kV images compared to 96-kV (all p < = 0.018). Anatomical structures and electrode position were rated significantly better in 120-kV CBCT for CI models from vendor A and C, while 120-kV did not provide improved image quality in CI models from vendor B. Radiation doses were significantly higher for 120-kV scans compared to 96-kV (0.15 vs. 0.08 mSv, p < 0.001).

CONCLUSIONS

120-kV and 96-kV CBCT provide good diagnostic images for the postoperative CI evaluation. While 120-kV showed improved depiction of temporal bone and CI electrode position compared to 96-kV in most CI models, the 120-kV protocol should be chosen wisely due to a substantially higher radiation exposure.

Bilateral simultaneous cochlear implantation is a safe method of hearing rehabilitation in adults

PURPOSE

Bilateral cochlear implantation is an effective treatment for patients with bilateral profound hearing loss. In contrast to children, adults mostly choose a sequential surgery. This study addresses whether simultaneous bilateral CI is associated with higher rates of complications compared to sequential implantation.

METHODS

169 bilateral CI surgeries were analyzed retrospectively. 34 of the patients were implanted simultaneously (group 1), whereas 135 patients were implanted sequentially (group 2). The duration of surgery, the incidence of minor and major complications and the duration of hospitalization of both groups were compared.

RESULTS

In group 1, the total operating room time was significantly shorter. The incidences of minor and major surgical complications showed no statistically significant differences. A fatal non-surgical complication in group 1 was particularly extensively reappraised without evidence of a causal relationship to the chosen mode of care. The duration of hospitalization was 0.7 days longer than in unilateral implantation but 2.8 days shorter than the combined two hospital stays in group 2.

CONCLUSION

In the synopsis of all considered complications and complication-relevant factors, equivalence of simultaneous and sequential cochlear implantation in adults in terms of safety was found. However, potential side effects related to longer surgical time in simultaneous surgery must be considered individually. Careful patient selection with special consideration to existing comorbidities and preoperative anesthesiologic evaluation is essential.

Cochlear Implantation in Hearing-Impaired Elderly: Clinical Challenges and Opportunities to Optimize Outcome

Cochlear implant (CI) overall provides a very good outcome, but speech comprehension outcome in the elderly is more variable. Several clinical factors play an important role. The management of residual hearing, the presence of comorbidities, and especially the progression of cognitive decline seem to be the clinical parameters that strongly determine the outcome of cochlear implantation and need to be discussed prospectively in the consultation process with the elderly hearing impaired. In the context of this review article, strategies for dealing with these will be discussed. Timely cochlear implantation should already be considered by hearing aid acousticians or practicing otolaryngologists and communicated or initiated with the patient. This requires intensive cooperation between hearing aid acousticians and experts in the clinic. In addition, residual hearing and comorbidities in the elderly need to be considered to make realistic predictions about speech comprehension with CI. Long-term aftercare and its different implementations should be discussed preoperatively, so that the elderly person with hearing impairments feels well taken care of together with his or her relatives. Elderly patients with hearing impairments benefit most from a CI in terms of speech comprehension if there is a large cochlear coverage (electrical or acoustic electrical) and the therapy is not hampered by comorbidities, especially cognitive decline.

Research Status and Future Development of Cochlear Reimplantation

Cochlear implants are the most successful sensory prostheses worldwide, and they can be useful for patients with severe and profound hearing impairment. However, various complications, including infection, pain, and device failure which is mainly due to falls and trauma, are associated with the use of cochlear implants. Reimplantation is required to replace the initial device in severe complications. Nevertheless, reimplantation can present certain surgical risks and may impose a significant economic and psychological burden on patients and their families; therefore, it requires greater attention and focus. This article presents a review of the literature on cochlear reimplantation and summarizes the current status, knowledge gaps, and future research directions on cochlear reimplantation. Since 1980s, cochlear reimplantation techniques can be considered to be relatively mature; however, some clinical and scientific problems remain unresolved, including the lack of a unified definition of cochlear reimplantation, non-standardized calculation of the reimplantation rat, and insufficient effect assessment. This review highlights the urgent need to establish an international consensus statement on cochlear reimplantation research to standardize the definition, calculation formulas of reimplantation rate, and follow-up systems.

Consistency of Using an Auditory Prosthesis Device Post a Sequentially Implanted Cochlear Implant: Data-Logging Evidence

Objectives

The aim of this study was to explore: 1) the average use of each device in sequentially implanted cochlear implants; 2) whether the inter-implant duration between implants produced any significant difference in the average use of the second implant; and 3) whether wearing hearing aids before the implantation of the second cochlear implant affects its average use.

Materials and methods

The study included 20 participants with bilateral Nucleus 24 implants (Cochlear Corporation, Lone Tree, CO). Data regarding various variables were extracted and then analyzed with IBM SPSS Statistics for Mac, version 23 (IBM Corp., Armonk, NY).

Results

The pediatric group included 14 subjects (average age 7.5 years) while the adult group comprised six subjects (average age 37.5 years). The average use of the second device was 0.9 hours per day more than the first in the pediatric group while it was 1.22 hours per day more in the adult group. We also divided the subjects on the basis of duration between the first and second devices and calculated the average use of each device by them. There was no significant difference (p>0.05). The average use by subjects who did and did not use hearing aids before implantation was also insignificant (p>0.05).

Conclusions

No significant difference between the average use of the first and second implants, between the inter-implant duration of the first and second implants, the average use of the second implant, and between using hearing aids before the implantation of the second device and the average use was observed.

Epidural recordings in cochlear implant users

OBJECTIVE

In the long term it is desirable for CI users to control their device via brain signals. A possible strategy is the use of auditory evoked potentials (AEPs). Several studies have shown the suitability of auditory paradigms for such an approach. However, these investigations are based on non-invasive recordings. When thinking about everyday life applications, it would be more convenient to use implanted electrodes for signal acquisition. Ideally, the electrodes would be directly integrated into the CI. Further it is to be expected that invasively recorded signals have higher signal quality and are less affected by artifacts.

APPROACH

In this project we investigated the feasibility of implanting epidural electrodes temporarily during CI surgery and the possibility to record AEPs in the course of several days after implantation. Intraoperatively, auditory brainstem responses were recorded, whereas various kinds of AEPs were recorded postoperatively. After a few days the epidural electrodes were removed.

MAIN RESULTS

Data sets of ten subjects were obtained. Invasively recorded potentials were compared subjectively and objectively to clinical standard recordings using surface electrodes. Especially the cortical evoked response audiometry depicted clearer N1 waves for the epidural electrodes which were also visible at lower stimulation intensities compared to scalp electrodes. Furthermore the signal was less disturbed by artifacts. The objective quality measure (based on data sets of six patients) showed a significant better signal quality for the epidural compared to the scalp recordings.

SIGNIFICANCE

Altogether the approach revealed to be feasible and well tolerated by the patients. The epidural recordings showed a clearly better signal quality than the scalp recordings with AEPs being clearer recognizable. The results of the present study suggest that including epidural recording electrodes in future CI systems will improve the everyday life applicability of auditory closed loop systems for CI subjects.

[Postoperative legal disputes involving patients with cochlear implants]

BACKGROUND

After the implantation of one or two cochlear implants additional problems often arise concerning the question which further costs have to be covered by statutory insurances or other insurance providers, e.g. within the framework of integration aid.

OBJECTIVE

This article provides an overview of judgments rendered by the German social courts. It was investigated whether and in which cases it is advisable for a patient to go to court, and how long the proceedings may take.

MATERIAL AND METHODS

A search was made for judgments in the two biggest commercial legal databases and in the database of the German social courts, using combinations of the search parameters "Cochlear", "Cochlea", "Implant", and "Implantat". The reviewed judgments were issued between 2002 and 2017.

RESULTS

A total of 13 judgments were found. The results varied according to the specifics of the individual case and 54% of the patients won their cases. The court procedures took between 2 months (starting from the filing of a complaint, date of application in this case unknown), and 6 years and 11 months.

CONCLUSION

This study showed that it is uncertain whether costs that are not caused directly by the surgery or the postoperative treatment will be remunerated. As each case is in principle unique, the results vary. Nevertheless, taking legal action is recommended after thorough consideration in cases where statutory insurances or other providers refuse to meet expenses incurred.