Minimum intraoperative testing battery for cochlear implantation: the international practice trend.

PURPOSE: In cochlear implantation (CI) surgery, there are a wide variety of intraoperative tests available. However, no clear guide exists on which tests must be performed as the minimum intraoperative testing battery. Toward this end, we studied the usage patterns, recommendations, and attitudes of practitioners toward intraoperative testing. METHODS: This study is a multicentric international survey of tertiary referral CI centers. A survey was developed and administered to a group of CI practitioners (n = 34) including otologists, audiologists and biomedical engineers. Thirty six participants were invited to participate in this study based on a their scientific outputs to the literature on the intraoperative testing in CI field and based on their high load of CI surgeries. Thirty four, from 15 countries have accepted the invitation to participate. The participants were asked to indicate the usage trends, perceived value, influence on decision making and duration of each intraoperative test. They were also asked to indicate which tests they believe should be included in a minimum test battery for routine cases. RESULTS: Thirty-two (94%) experts provided responses. The most frequently recommended tests for a minimum battery were facial nerve monitoring, electrode impedance measurements, and measurements of electrically evoked compound action potentials (ECAPs). The perceived value and influence on surgical decision-making also varied, with high-resolution CT being rated the highest on both measures. CONCLUSION: Facial nerve monitoring, electrode impedance measurements, and ECAP measurements are currently the core tests of the intraoperative test battery for CI surgery.

International Consensus Statements on Intraoperative Testing for Cochlear Implantation Surgery.

OBJECTIVES: A wide variety of intraoperative tests are available in cochlear implantation. However, no consensus exists on which tests constitute the minimum necessary battery. We assembled an international panel of clinical experts to develop, refine, and vote upon a set of core consensus statements. DESIGN: A literature review was used to identify intraoperative tests currently used in the field and draft a set of provisional statements. For statement evaluation and refinement, we used a modified Delphi consensus panel structure. Multiple interactive rounds of voting, evaluation, and feedback were conducted to achieve convergence. RESULTS: Twenty-nine provisional statements were included in the original draft. In the first voting round, consensus was reached on 15 statements. Of the 14 statements that did not reach consensus, 12 were revised based on feedback provided by the expert practitioners, and 2 were eliminated. In the second voting round, 10 of the 12 revised statements reached a consensus. The two statements which did not achieve consensus were further revised and subjected to a third voting round. However, both statements failed to achieve consensus in the third round. In addition, during the final revision, one more statement was decided to be deleted due to overlap with another modified statement. CONCLUSIONS: A final core set of 24 consensus statements was generated, covering wide areas of intraoperative testing during CI surgery. These statements may provide utility as evidence-based guidelines to improve quality and achieve uniformity of surgical practice.

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: 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.

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.

Unilateral Cochlear Implants for Severe, Profound, or Moderate Sloping to Profound Bilateral Sensorineural Hearing Loss: A Systematic Review and Consensus Statements.

Importance: Cochlear implants are a treatment option for individuals with severe, profound, or moderate sloping to profound bilateral sensorineural hearing loss (SNHL) who receive little or no benefit from hearing aids; however, cochlear implantation in adults is still not routine. Objective: To develop consensus statements regarding the use of unilateral cochlear implants in adults with severe, profound, or moderate sloping to profound bilateral SNHL. Design, Setting, and Participants: This study was a modified Delphi consensus process that was informed by a systematic review of the literature and clinical expertise. Searches were conducted in the following databases: (1) MEDLINE In-Process & Other Non-Indexed Citations and Ovid MEDLINE, (2) Embase, and (3) the Cochrane Library. Consensus statements on cochlear implantation were developed using the evidence identified. This consensus process was relevant for the use of unilateral cochlear implantation in adults with severe, profound, or moderate sloping to profound bilateral SNHL. The literature searches were conducted on July 18, 2018, and the 3-step Delphi consensus method took place over the subsequent 9-month period up to March 30, 2019. Main Outcomes and Measures: A Delphi consensus panel of 30 international specialists voted on consensus statements about cochlear implantation, informed by an SR of the literature and clinical expertise. This vote resulted in 20 evidence-based consensus statements that are in line with clinical experience. A modified 3-step Delphi consensus method was used to vote on and refine the consensus statements. This method consisted of 2 rounds of email questionnaires and a face-to-face meeting of panel members at the final round. All consensus statements were reviewed, discussed, and finalized at the face-to-face meeting. Results: In total, 6492 articles were identified in the searches of the electronic databases. After removal of duplicate articles, 74 articles fulfilled all of the inclusion criteria and were used to create the 20 evidence-based consensus statements. These 20 consensus statements on the use of unilateral cochlear implantation in adults with SNHL were relevant to the following 7 key areas of interest: level of awareness of cochlear implantation (1 consensus statement); best practice clinical pathway from diagnosis to surgery (3 consensus statements); best practice guidelines for surgery (2 consensus statements); clinical effectiveness of cochlear implantation (4 consensus statements); factors associated with postimplantation outcomes (4 consensus statements); association between hearing loss and depression, cognition, and dementia (5 consensus statements); and cost implications of cochlear implantation (1 consensus statement). Conclusions and Relevance: These consensus statements represent the first step toward the development of international guidelines on best practices for cochlear implantation in adults with SNHL. Further research to develop consensus statements for unilateral cochlear implantation in children, bilateral cochlear implantation, combined electric-acoustic stimulation, unilateral cochlear implantation for single-sided deafness, and asymmetrical hearing loss in children and adults may be beneficial for optimizing hearing and quality of life for these patients.

Hearing Preservation Outcomes for 139 Cochlear Implant Recipients Using a Thin Straight Electrode Array.

OBJECTIVE: To assess the hearing preservation outcomes in a large group of adult cochlear implant recipients implanted with a thin straight electrode array using atraumatic surgical techniques. Factors affecting hearing preservation will be investigated. STUDY DESIGN: Prospective cohort study undertaken at the Royal Victorian Eye and Ear Hospital in Melbourne, Australia from December 2010 to May 2015. SETTING: Tertiary academic hospital. PATIENTS: One hundred thirty-nine adults undergoing cochlear implantation (CI). MAIN OUTCOME MEASURE: Primary outcome measure of interest was pre and postoperative pure-tone audiometry. RESULTS: Median low-frequency hearing change for the whole group of 139 recipients was -22.5 dB at the 3 months postop point. Eighty-six participants had functional preoperative low-frequency hearing (≤70 dB average at 250 and 500 Hz). Of these, 90.7% retained measureable hearing at 3 months postimplant. 39.5% of this original 86 participants retained functional hearing at 3 months postimplant. At 12 months postimplant, those who retained functional hearing at 3 months had no significant change in hearing. The group who lost functional hearing continued to have a significant deterioration in low-frequency hearing. Degree of hearing loss preimplant was identified as a predictor for the preservation of hearing postoperatively. CONCLUSION: Preservation of hearing is possible following atraumatic cochlear implant surgery with a thin straight electrode array. The amount of hearing preserved seems to be variable, and factors related to this variability are not yet known. The results of the present study suggest preoperative low-frequency hearing at or better than 45 dB may be related to preservation of functional hearing.

Anatomic comparison of nasal versus lateral surgical access to the petrous apex.

To compare anatomic access to the petrous apex via the nasal and lateral approaches. Hundred consecutive fine-cut CT temporal bones at the Royal Melbourne Hospital from July 27, 2007 to October 30, 2010 were reviewed. Easy lateral access allowed use of a 4 mm burr past vital structures. Easy nasal access was defined as sphenoid pneumatization to/beyond the posterior sella and laterally beyond the maxillary/vidian nerves. Three patients with petrous apex pathology were also reviewed. Easy lateral and nasal access occurred in 74 (37%) and 79 (39.5%) sides, respectively. Easy nasal and lateral access were not strongly correlated (r = 0.10, P = 0.15). A well-pneumatized mastoid (62.5%) was strongly correlated with a large sphenoid (63%, P < 0.001). Pneumatization of the mastoid corresponds to sphenoid sinus size. However, surgical access to the petrous apex is more determined by proximity of vital structures. Easy surgical access via the nasal or lateral approaches was not strongly correlated. Petrous apex lesions requiring surgery should be considered for both approaches.

The new Nucleus 5 model cochlear implant: a new surgical technique and early clinical results.

OBJECTIVE: The Nucleus 5 or CI500 series cochlear implants are the new generation of Nucleus(®) cochlear implants. The receiver-stimulator package has a low profile without a pedestal projecting from the medial surface. This study aimed to demonstrate that the new design can facilitate a minimally invasive surgical approach, without the need for tie-down sutures and without a seat drilled for the receiver-stimulator package. METHODS: The surgical technique involved placing the device directly on the surface of the bone in a secure sub-periosteal pocket with a channel drilled for the lead. A well or ramped seat was not drilled and tie-down sutures were not used. Measurements were taken from the transmitting coil to the tragus and the coil to the lobule immediately after implantation, and serially thereafter to document implant position. RESULTS: To date, over 200 implants have been performed with the Nucleus 5 device. In all cases, healing was uneventful without major complications. Of 137 patients with at least 6-week follow-up data, 8% showed a measurement change of greater than 1 cm whereas only 4.4% demonstrated any clinically evident movement. None had any complications relating to migration and none required repositioning of the device. DISCUSSION: The new design can safely be inserted without drilling a well for the receiver-stimulator package. Some early post-operative movement of the package was observed which caused no clinical impact. This modified surgical technique reduces the risk of intracranial complications and reduces operating time.

Planned simultaneous bilateral cochlear implant operations: how often do children receive only one implant?

OBJECTIVE: The aim of this study was to determine the proportion of planned simultaneous cochlear implant operations that do not result in simultaneous cochlear implants on the day of surgery. The frequency with which this occurs has not been reported in the literature, and such information is important for parents' pre-operative decision making. METHODS: A retrospective review was conducted of pediatric cochlear implant operations performed in the period January 2007-July 2010 at the Melbourne Cochlear Implant Clinic. The number of planned simultaneous cochlear implant procedures and the results of these surgeries were catalogued. Reasons for not proceeding with simultaneous cochlear implants as planned were also identified. RESULTS: In the time period examined, there were a total of 50 planned simultaneous cochlear implant operations. Of these planned simultaneous operations, 22% did not result in bilateral cochlear implants on the day of surgery, with all children involved receiving a first-side cochlear implant only. In the majority of cases, the reason for a first-side cochlear implant only was otitis media. CONCLUSION: In the time period examined, a considerable proportion of planned simultaneous cochlear implant operations did not result in simultaneous bilateral implantation on the day of surgery. It is important that the likelihood of this outcome is discussed with families during pre-operative counseling as it may influence their decision making.

Outcomes of the overlay graft technique in tympanoplasty.

BACKGROUND: This audit was undertaken to review the outcomes achieved with the overlay graft technique of tympanic membrane repair in tympanoplasty surgery. METHODS: The charts of all patients who underwent tympanoplasty, in whom an overlay graft technique of temporalis fascia tympanic membrane repair was used, between 1994 and 2007 were reviewed. Information with respect to patient demographics, presence of cholesteatoma or active infection and perforation size was documented. Details of the surgical procedure and clinical outcomes and pre- and post-operative hearing thresholds were recorded in a computer database. RESULTS: A total of 147 overlay graft procedures were performed in 130 patients. Graft failure with reperforation occurred following five procedures, for an overall success rate of 96.6%. Eighty Type 1 tympanoplasty procedures were performed in which one failure occurred for a 98.75% success rate. Overlay grafting was combined with intact canal wall mastoidectomy (ICW) in 38 cases and with modified radical mastoidectomy (MRM) in 17 cases for a success rate of 93.8 and 95%, respectively. Delayed graft healing as a result of infection, problems such as epithelial pearl, blunting and myringitis occurred in 39 cases (26.5%). Thirty-one cases underwent procedures for ossicular chain reconstruction, 21 of which were 2nd stage procedures. Hearing outcomes were significantly better with Type 1 tympanoplasty compared with ICW or MRM procedures. CONCLUSION: This review demonstrates the overlay graft technique of tympanoplasty to be highly successful for tympanic membrane repair, particularly for the more difficult cases such as revision surgery, subtotal perforations and mesotympanic cholesteatoma.

Quality of life among acoustic neuroma patients managed by microsurgery, radiation, or observation.

OBJECTIVE: The main aim of this study was to examine differences in quality of life (QoL) among acoustic neuroma patients across the management options of microsurgery, radiation, and observation. Additional aims were to describe QoL and investigate management, medical, and demographic factors that predicted QoL in this patient group. STUDY DESIGN: Cross-sectional design, using a postal questionnaire. SETTING: Tertiary referral centers. PATIENTS: Participants included 180 adults diagnosed with, or treated for, a unilateral acoustic neuroma within 5 years of questionnaire distribution. The mean age of participants was 56.5 years, and 107 (59.4%) were female. INTERVENTION(S): Patients' acoustic neuromas were managed with microsurgery, radiation, or observation. MAIN OUTCOME MEASURE(S): Current QoL was measured using the Short Form 12 Version 2 (SF-12), and postmanagement changes in QoL were assessed with the Glasgow Benefit Inventory (GBI). RESULTS: No significant differences in SF-12 scores were found across microsurgery, radiation, and observation patients. However, microsurgery patients reported more deterioration on the GBI general well-being subscale than radiation patients and more improvement in the GBI social support scale than observation patients. Number of symptoms was a consistent predictor of SF-12 and GBI scores. CONCLUSION: This is only the second study to use multivariate statistical techniques and a large sample to examine QoL across the acoustic neuroma management options of microsurgery, radiation, and observation. There were few differences in QoL outcomes across management groups. Number of symptoms was an important factor in current QoL and postmanagement changes in QoL.

Cochlear implantation in neurofibromatosis type 2 after radiation therapy.

OBJECTIVE: To investigate the results of cochlear implantation in patients with neurofibromatosis Type 2 (NF2) who have previously been treated with radiation therapy to the vestibular schwannoma (VS) in their only hearing ear. STUDY DESIGN: A retrospective review of the Melbourne Cochlear implant database was undertaken to identify patients with NF2 undergoing cochlear implantation in whom previous radiation therapy had been performed to control their VS (ipsilateral tumor). Three patients were identified. A case note review was undertaken and data collected on preoperative and postoperative speech perception testing. SETTING: Melbourne Cochlear implant center. RESULTS: All 3 patients were daily cochlear implant users. There was improvement in speech perception scores in 2 cases, with the 3rd case unable, for unrelated medical reasons, to complete postoperative testing. Subjectively, the third patient reported a dramatic improvement in communication and is a daily user of his implant. CONCLUSION: Cochlear implantation results in improved hearing in a select group of NF2 patients who have undergone radiation treatment to control their VS.

Speech detection and localization results and clinical outcomes for children receiving sequential bilateral cochlear implants before four years of age.

The aim of this study was to describe the adaptation to bilateral cochlear implant use and the perceptual benefits demonstrated by 10 children who were successful users of a first implant when a second was received before four years of age. Although one subject rejected the second implant at switch-on, the nine subjects who accepted the device adapted easily to bilateral implant use and developed useful listening skills with the second implant. Tests of localization (left versus right) and speech detection in noise were administered in the unilateral and bilateral conditions, usually after six months experience. All subjects demonstrated some bilateral benefit on speech detection testing (mostly due to a headshadow effect), and the majority localized left versus right. Results suggested that outcomes may be negatively impacted by increased age at the time of second implant switch-on. The majority of the subjects adapted well to bilateral implant use within six months and demonstrated some perceptual benefit and, according to subjective parent reports, improved daily functioning; however, device rejection must be discussed pre-operatively as a possibility.

Laser-assisted stapedotomy with a Nitinol heat-crimping prosthesis: Outcomes compared with a platinum fluoroplastic prosthesis.

OBJECTIVE: To assess the hearing outcomes achieved with a Nitinol heat-crimping prosthesis when used with a laser-assisted stapedotomy for otosclerosis. STUDY DESIGN: Prospective assessment of 50 stapedotomies performed in 48 patients. Data collected included audiological results and duration of hospital admission. Outcomes were compared with a previously reported series of 66 stapedotomies performed in 59 patients. SETTING: Tertiary referral center and private practice. RESULTS: In the Nitinol group, hearing was improved in all cases (100%). The air-bone gap (ABG) was closed to within 10 dB in 48 (96%). This group's results are significantly better (P < or = 0.01) than those of the platinum fluoroplastic group, in whom ABG was within 10 dB in 74 percent. CONCLUSION: Laser-assisted stapedotomy, under local anesthesia with sedation, using a Nitinol heat-crimping prosthesis is a safe, well-tolerated technique with which excellent audiological results can be achieved.

Indications for and outcomes of mastoid obliteration in cochlear implantation.

OBJECTIVE: To review the indications, efficacy, and long-term outcomes of mastoid obliteration in cochlear implant surgery. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Seventeen patients who underwent a mastoid obliteration procedure to facilitate the insertion of a cochlear implant between 1978 and 2005. INTERVENTION: Mastoid obliteration procedure before cochlear implantation. MAIN OUTCOME MEASURES: Revision rate of the mastoid obliteration and cochlear implantation, postoperative audiometric scores (consonant-nucleus-consonant words/phonemes, Central Institute for the Deaf sentences, City University New York sentences in quiet and in noise), and incidence of complications. RESULTS: There were 17 patients with a median age of 60 years (range, 3-79 yr). Eight patients required mastoid obliteration for active chronic suppurative otitis media before cochlear implantation. Another 8 patients had existing mastoid cavities requiring obliteration (modified radical [n = 5] and fenestration cavities [n = 3]). A single patient with a sclerotic mastoid and an anterior sigmoid sinus underwent obliteration because of inadequate surgical access. The technique of obliteration was radical mastoidectomy with eustachian tube occlusion, blind sac closure of the external auditory canal, and cavity obliteration with either temporalis muscle flap (n = 15) or abdominal fat (n = 2). Cochlear implantation and mastoid obliteration were performed as a two-stage procedure in 10 patients and as a single-stage procedure in 7. Two patients required revision of the mastoid obliteration. At follow-up, all patients had stable obliterated cavities. Fifteen patients obtained significant improvement in speech discrimination scores, whereas 2 patients obtained some benefit from the cochlear implant through the perception of environmental sounds. CONCLUSION: For patients with chronic suppurative otitis media or existing mastoid cavities, the obliteration with temporalis muscle or abdominal fat is an effective technique to facilitate safe cochlear implantation.

Effects of vestibulo-ocular reflex exercises on vestibular compensation after vestibular schwannoma surgery.

OBJECTIVE: To assess vestibular function in a large group of vestibular schwannoma patients so that we could determine whether simple vestibular exercises speed vestibular dysfunction recovery after tumor removal surgery. STUDY DESIGN: A prospective investigation of the vestibular dysfunction experienced by patients in the first 12 weeks after surgery. SETTING: Vestibular investigation unit at a tertiary referral institution. PATIENTS: Sixty-five patients with identified vestibular schwannoma referred for preoperative vestibular investigations. Thirty-two men and 33 women, with a mean age 51 years (range, 24-77 yr). INTERVENTIONS: There were 27 control patients, 30 exercise patients, and 8 patients that had balance physiotherapy. Exercise patients began simple vestibulo-ocular reflex gaze stabilization exercises 3 days after surgery. MAIN OUTCOME MEASURES: Postoperative vestibular function testing was performed at 2 to 3, 6 to 7, and 10 to 12 weeks after surgery. Objective measurements of vestibular compensation status were as follows: spontaneous nystagmus and sinusoidal harmonic acceleration asymmetry and gain values. Dizziness Handicap Inventory questionnaires were used to assess subjective perceptions. RESULTS: The main findings were reduced dispersion in vestibulo-ocular reflex asymmetry at 2 to 3 weeks, reduced mean in asymmetry at 6 to 7 weeks, less dizziness/imbalance according to the Dizziness Handicap Inventory questionnaire, and that preoperative caloric tests did not predict postoperative severity of vestibular systems. CONCLUSION: This large study provided unique evidence that a program of simple vestibular exercises and education can speed the rate of compensation after vestibular schwannoma surgery.