1
|
Fleet A, Nikookam Y, Radotra A, Gowrishankar S, Metcalfe C, Muzaffar J, Smith ME, Monksfield P, Bance M. Outcomes following cochlear implantation with eluting electrodes: A systematic review. Laryngoscope Investig Otolaryngol 2024; 9:e1263. [PMID: 38855776 PMCID: PMC11160184 DOI: 10.1002/lio2.1263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 02/22/2024] [Accepted: 04/25/2024] [Indexed: 06/11/2024] Open
Abstract
Objectives To establish audiological and other outcomes following cochlear implantation in humans and animals with eluting electrodes. Methods Systematic review and narrative synthesis. Databases searched (April 2023): MEDLINE, EMBASE, CENTRAL, ClinicalTrials.gov, and Web of Science. Studies reporting outcomes in either humans or animals following cochlear implantation with a drug-eluting electrode were included. No limits were placed on language or year of publication. Risk of bias assessment was performed on all included studies using either the Brazzelli or Systematic Review Centre for Laboratory animal Experimentation (SYRCLE) assessment tools. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement. Results Searches identified 146 abstracts and 108 full texts. Of these, 18 studies met the inclusion criteria, reporting outcomes in 523 animals (17 studies) and 24 humans (1 study). Eluting electrodes included dexamethasone (16 studies), aracytine (1 study), nicotinamide adenine dinucleotide (1 study), the growth factors insulin-like growth factor 1 (IGF1) and hepatocyte growth factor (HGF) (1 study), and neurotrophin-3 (1 study). All included studies compare outcomes following implantation with an eluting electrode with a control non-eluting electrode. In the majority of studies, audiological outcomes (e.g., auditory brainstem response threshold) were superior following implantation with an eluting electrode compared with a standard electrode. Most studies which investigated post-implantation impedance reported lower impedance following implantation with an eluting electrode. The influence of eluting electrodes on other reported outcomes (including post-implantation cochlear fibrosis and the survival of hair cells and spiral ganglion neurons) was more varied across the included studies. Conclusions Eluting electrodes have shown promise in animal studies in preserving residual hearing following cochlear implantation and in reducing impedance, though data from human studies remain lacking. Further in-human studies will be required to determine the clinical usefulness of drug-eluting cochlear implants as a future treatment for sensorineural hearing loss.
Collapse
Affiliation(s)
- Alex Fleet
- Department of Clinical Neurosciences, Addenbrooke's Health CampusUniversity of CambridgeCambridgeUK
| | - Yasmin Nikookam
- Department of Ear, Nose and Throat SurgeryUniversity Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Mindelsohn WayEdgbastonBirminghamUK
| | - Anshul Radotra
- The Royal Wolverhampton NHS Trust New Cross HospitalWolverhamptonUK
| | - Shravan Gowrishankar
- Department of Clinical Neurosciences, Addenbrooke's Health CampusUniversity of CambridgeCambridgeUK
| | | | - Jameel Muzaffar
- Department of Clinical Neurosciences, Addenbrooke's Health CampusUniversity of CambridgeCambridgeUK
- Department of Ear, Nose and Throat SurgeryUniversity Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Mindelsohn WayEdgbastonBirminghamUK
| | - Matthew E. Smith
- Department of Clinical Neurosciences, Addenbrooke's Health CampusUniversity of CambridgeCambridgeUK
| | - Peter Monksfield
- Department of Ear, Nose and Throat SurgeryUniversity Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Mindelsohn WayEdgbastonBirminghamUK
| | - Manohar Bance
- Department of Clinical Neurosciences, Addenbrooke's Health CampusUniversity of CambridgeCambridgeUK
| |
Collapse
|
2
|
Dhanasingh A, Nielsen SB, Beal F, Schilp S, Hessler R, Jolly C, Hochmair I. Cochlear implant electrode design for safe and effective treatment. Front Neurol 2024; 15:1348439. [PMID: 38756216 PMCID: PMC11096578 DOI: 10.3389/fneur.2024.1348439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 04/09/2024] [Indexed: 05/18/2024] Open
Abstract
The optimal placement of a cochlear implant (CI) electrode inside the scala tympani compartment to create an effective electrode-neural interface is the base for a successful CI treatment. The characteristics of an effective electrode design include (a) electrode matching every possible variation in the inner ear size, shape, and anatomy, (b) electrically covering most of the neuronal elements, and (c) preserving intra-cochlear structures, even in non-hearing preservation surgeries. Flexible electrode arrays of various lengths are required to reach an angular insertion depth of 680° to which neuronal cell bodies are angularly distributed and to minimize the rate of electrode scalar deviation. At the time of writing this article, the current scientific evidence indicates that straight lateral wall electrode outperforms perimodiolar electrode by preventing electrode tip fold-over and scalar deviation. Most of the available literature on electrode insertion depth and hearing outcomes supports the practice of physically placing an electrode to cover both the basal and middle turns of the cochlea. This is only achievable with longer straight lateral wall electrodes as single-sized and pre-shaped perimodiolar electrodes have limitations in reaching beyond the basal turn of the cochlea and in offering consistent modiolar hugging placement in every cochlea. For malformed inner ear anatomies that lack a central modiolar trunk, the perimodiolar electrode is not an effective electrode choice. Most of the literature has failed to demonstrate superiority in hearing outcomes when comparing perimodiolar electrodes with straight lateral wall electrodes from single CI manufacturers. In summary, flexible and straight lateral wall electrode type is reported to be gentle to intra-cochlear structures and has the potential to electrically stimulate most of the neuronal elements, which are necessary in bringing full benefit of the CI device to recipients.
Collapse
|
3
|
Sipari S, Iso-Mustajärvi M, Linder P, Dietz A. Insertion Results and Hearing Outcomes of a Slim Lateral Wall Electrode. J Int Adv Otol 2024; 20:1-7. [PMID: 38454281 PMCID: PMC10895868 DOI: 10.5152/iao.2024.22962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 05/14/2023] [Indexed: 03/09/2024] Open
Abstract
BACKGROUND The clinical outcomes of cochlear implantation vary for several reasons. It is necessary to study the different electrodes and variables for further development. The aim of this study is to report the clinical outcomes of a new slim lateral wall electrode (SlimJ). METHODS Data of 25 cochlear implantations in 23 patients with the SlimJ electrode were retrospectively collected. The insertion results were assessed by image fusion of the preoperative computed tomography (CT), magnetic resonance imaging (MRI), and postoperative cone-beam CT. The hearing outcomes were evaluated by the improvement of speech recognition in noise, measured preoperatively and at follow-up. Postoperative pure-tone thresholds were obtained in cases with preoperative functional low frequency hearing [PTA (0.125-0.5 kHz) ≤ 80 dB HL]. RESULTS The preoperative mean speech reception threshold (SRT) was +0.6 dB signal-to-noise ratio (SNR) (SD ± 4.2 dB) and the postoperative -3.5 dB SNR (SD ± 2.3 dB). The improvements between the preoperative and postoperative SRT levels ranged from 0.0 to 15.1 dB, with a mean improvement of 4.2 dB (SD ± 3.6 dB). Residual hearing in low frequencies (mean PTA(125-500 Hz)) was preserved within 30 dB HL in 70% and within 15 dB HL in 40% of patients who had preoperatively functional low frequency hearing. Mean insertion depth angle (IDA) was 401° (SD ± 41°). We observed scalar translocations from scala tympani to scala vestibuli in 2 ears (9%). CONCLUSION The relatively atraumatic insertion characteristics make the SlimJ array feasible for hearing preservation cochlear implantation. The hearing outcomes are comparable to those reported for other electrodes and devices.
Collapse
Affiliation(s)
- Sini Sipari
- Department of Otorhinolaryngology, Kuopio University Hospital, Kuopio, Finland
- Department of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Matti Iso-Mustajärvi
- Department of Otorhinolaryngology, Kuopio University Hospital, Kuopio, Finland
- Department of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Pia Linder
- Department of Otorhinolaryngology, Kuopio University Hospital, Kuopio, Finland
- Department of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Aarno Dietz
- Department of Otorhinolaryngology, Kuopio University Hospital, Kuopio, Finland
- Department of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| |
Collapse
|
4
|
Geiger S, Iso-Mustajärvi M, Nauwelaers T, Avci E, Julkunen P, Linder P, Silvast T, Dietz A. Automatic electrode scalar location assessment after cochlear implantation using a novel imaging software. Sci Rep 2023; 13:12416. [PMID: 37524776 PMCID: PMC10390550 DOI: 10.1038/s41598-023-39275-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 07/22/2023] [Indexed: 08/02/2023] Open
Abstract
As of today, image-based assessment of cochlear implant electrode array location is not part of the clinical routine. Low resolution and contrast of computer tomography (CT) imaging, as well as electrode array artefacts, prevent visibility of intracochlear structures and result in low accuracy in determining location of the electrode array. Further, trauma assessment based on clinical-CT images requires a uniform image-based trauma scaling. Goal of this study was to evaluate the accuracy of a novel imaging software to detect electrode scalar location. Six cadaveric temporal bones were implanted with Advanced Bionics SlimJ and Mid-Scala electrode arrays. Clinical-CT scans were taken pre- and postoperatively. In addition, micro-CTs were taken post-operatively for validation. The electrode scalar location rating done by the software was compared to the rating of two experienced otosurgeons and the micro-CT images. A 3-step electrode scalar location grading scale (0 = electrode in scala tympani, 1 = interaction of electrode with basilar membrane/osseous spiral lamina, 2 = translocation of electrode into scala vestibuli) was introduced for the assessment. The software showed a high sensitivity of 100% and a specificity of 98.7% for rating the electrode location. The correlation between rating methods was strong (kappa > 0.890). The software gives a fast and reliable method of evaluating electrode scalar location for cone beam CT scans. The introduced electrode location grading scale was adapted for assessing clinical CT images.
Collapse
Affiliation(s)
- S Geiger
- Advanced Bionics, European Research Center, Hannover, Germany.
| | - M Iso-Mustajärvi
- Department of Otorhinolaryngology, Kuopio University Hospital, Kuopio, Finland
| | - T Nauwelaers
- Advanced Bionics, European Research Center, Hannover, Germany
| | - E Avci
- Advanced Bionics, European Research Center, Hannover, Germany
| | - P Julkunen
- Department of Technical Physics, University of Eastern Finland, Kuopio, Finland
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
| | - P Linder
- Department of Otorhinolaryngology, Kuopio University Hospital, Kuopio, Finland
| | - T Silvast
- SIB Labs, Dempartment of Technical Physics, University of Eastern Finland, Kuopio, Finland
| | - A Dietz
- Department of Otorhinolaryngology, Kuopio University Hospital, Kuopio, Finland
| |
Collapse
|
5
|
Saoji AA, Graham MK, Adkins WJ, Koka K, Carlson ML, Neff BA, Driscoll CLW, Fitzpatrick DC. Multi-Frequency Electrocochleography and Electrode Scan to Identify Electrode Insertion Trauma during Cochlear Implantation. Brain Sci 2023; 13:brainsci13020330. [PMID: 36831873 PMCID: PMC9954676 DOI: 10.3390/brainsci13020330] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/27/2023] [Accepted: 02/10/2023] [Indexed: 02/17/2023] Open
Abstract
Intraoperative electrocochleography (ECOG) is performed using a single low-frequency acoustic stimulus (e.g., 500 Hz) to monitor cochlear microphonics (CM) during cochlear implant (CI) electrode insertion. A decrease in CM amplitude is commonly associated with cochlear trauma and is used to guide electrode placement. However, advancement of the recording electrode beyond the sites of CM generation can also lead to a decrease in CM amplitude and is sometimes interpreted as cochlear trauma, resulting in unnecessary electrode manipulation and increased risk of cochlear trauma during CI electrode placement. In the present study, multi-frequency ECOG was used to monitor CM during CI electrode placement. The intraoperative CM tracings were compared with electrode scan measurements, where CM was measured for each of the intracochlear electrodes. Comparison between the peak CM amplitude measured during electrode placement and electrode scan measurements was used to differentiate between different mechanisms for decrease in CM amplitude during CI electrode insertion. Analysis of the data shows that both multi-frequency electrocochleography and electrode scan could potentially be used to differentiate between different mechanisms for decreasing CM amplitude and providing appropriate feedback to the surgeon during CI electrode placement.
Collapse
Affiliation(s)
- Aniket A. Saoji
- Department of Otolaryngology Head and Neck Surgery, Mayo Clinic, Rochester, MN 55905, USA
- Correspondence:
| | - Madison K. Graham
- Department of Otolaryngology Head and Neck Surgery, Mayo Clinic, Rochester, MN 55905, USA
| | - Weston J. Adkins
- Department of Otolaryngology Head and Neck Surgery, Mayo Clinic, Rochester, MN 55905, USA
| | - Kanthaiah Koka
- Department of Research and Technology, Advanced Bionics, Valencia, CA 91355, USA
| | - Matthew L. Carlson
- Department of Otolaryngology Head and Neck Surgery, Mayo Clinic, Rochester, MN 55905, USA
| | - Brian A. Neff
- Department of Otolaryngology Head and Neck Surgery, Mayo Clinic, Rochester, MN 55905, USA
| | - Colin L. W. Driscoll
- Department of Otolaryngology Head and Neck Surgery, Mayo Clinic, Rochester, MN 55905, USA
| | - Douglas C. Fitzpatrick
- Department of Otolaryngology-Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| |
Collapse
|
6
|
Summating Potential as Marker of Intracochlear Position in Bipolar Electrocochleography. Ear Hear 2023; 44:118-134. [PMID: 35894668 DOI: 10.1097/aud.0000000000001259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Cochlear implantation criteria include subjects with residual low-frequency hearing. To minimize implantation trauma and to avoid unwanted interactions of electric- and acoustic stimuli, it is often recommended to stop cochlear implantation before the cochlear implant (CI) reaches the cochlear partition with residual hearing, as determined by an audiogram. For this purpose, the implant can be used to record acoustically evoked signals during implantation, including cochlear compound action potentials (CAP), cochlear microphonics (CMs), and summating potentials (SPs). The former two have previously been used to monitor residual hearing in clinical settings. DESIGN In the present study we investigated the use of intracochlear, bipolar SP recordings to determine the exact cochlear position of the contacts of implanted CIs in guinea pig cochleae (n = 13). Polarity reversals of SPs were used as a functional marker of intracochlear position. Micro computed tomography (µCT) imaging and a modified Greenwood function were used to determine the cochleotopic positions of the contacts in the cochlea. These anatomical reconstructions were used to validate the SP-based position estimates. RESULTS The precision of the SP-based position estimation was on average within ± 0.37 octaves and was not impaired by moderate hearing loss caused by noise exposure after implantation. It is important to note that acute hearing impairment did not reduce the precision of the method. The cochleotopic position of CI accounted for ~70% of the variability of SP polarity reversals. Outliers in the dataset were associated with lateral CI positions. Last, we propose a simplified method to avoid implantation in functioning parts of the cochlea by approaching a predefined frequency region using bipolar SP recordings through a CI. CONCLUSIONS Bipolar SP recordings provide reliable information on electrode position in the cochlea. The position estimate remains reliable after moderate hearing loss. The technique presented here could be applied during CI surgery to monitor the CI approach to a predefined frequency region.
Collapse
|
7
|
Functional Outcomes and Quality of Life after Cochlear Implantation in Patients with Long-Term Deafness. J Clin Med 2022; 11:jcm11175156. [PMID: 36079089 PMCID: PMC9457208 DOI: 10.3390/jcm11175156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/28/2022] [Accepted: 08/30/2022] [Indexed: 11/17/2022] Open
Abstract
Background: Hearing-related quality of life (QoL) after cochlear implantation (CI) is as important as audiological performance. We evaluated the functional results and QoL after CI in a heterogeneous patient cohort with emphasis on patients with long-term deafness (>10 years). Methods: Twenty-eight patients (n = 32 implanted ears, within n = 12 long-term deaf ears) implanted with a mid-scala electrode array were included in this retrospective mono-centric cohort study. Speech intelligibility for monosyllables (SIM), speech reception thresholds (SRT50) and QoL with Nijmegen Cochlear Implant Questionnaire (NCIQ) were registered. Correlation of SIM and QoL was analyzed. Results: SIM and SRT50 improved significantly 12 months postoperatively up to 54.8 ± 29.1% and 49.3 ± 9.6 dB SPL, respectively. SIM progressively improved up to 1 year, but some early-deafened, late implanted patients developed speech understanding several years after implantation. The global and all subdomain QoL scores increased significantly up to 12 months postoperatively and we found a correlation of SIM and global QoL score at 12 months postoperatively. Several patients of the “poor performer” (SIM < 40%) group reported high improvement of hearing-related QoL. Conclusions: Cochlear implantation provides a benefit in hearing-related QoL, even in some patients with low postoperative speech intelligibility results. Consequently, hearing-related QoL scores should be routinely used as outcome measure beside standard speech understanding tests, as well. Further studies with a prospective multi-centric design are needed to identify factors influencing post-implantation functional results and QoL in the patient group of long-term deafness.
Collapse
|