The Prevalence of Cochlear Obliteration After Labyrinthectomy Using Magnetic Resonance Imaging and the Implications for Cochlear Implantation

Surgical Outcomes of Simultaneous Cochlear Implantation and Intracochlear Schwannoma Removal

OBJECTIVE

Intracochlear schwannoma is very rare, and complete loss of hearing is inevitable after the removal of this tumor. Here, we discuss cochlear implantation (CI) performed simultaneously with the removal of an intracochlear schwannoma.

STUDY DESIGN

Retrospective single-center study.

SETTING

Tertiary medical institute.

METHODS

Simultaneous CI and intracochlear schwannoma removal were performed in 4 subjects. After subtotal cochleostomy, the tumors were removed meticulously, with preservation of the modiolus. A new slim modiolar electrode (Nucleus CI632) was placed in a manner that hugged the modiolus. The surgical outcomes of functional gain, word recognition score (WRS), sound localization, and hearing in noise and speech intelligibility tests were investigated.

RESULTS

Intracochlear schwannomas were removed successfully from the 4 patients, with no remnant tumor. The mean aided hearing threshold 6 months after surgery was 25.0 ± 1.8 dB, and the mean-aided WRS with a 60 dB stimulus was 36.0 ± 18.8% (range 16%-60%). The Categorical Auditory Performance (CAP) score of the 3 single-sided deafness patients under contralateral ear masking was 7. The CAP score of the patient with bilateral sensorineural hearing loss was 6, which improved from a preoperative score of 0.

CONCLUSION

When an intracochlear schwannoma does not completely invade the modiolus, CI with simultaneous tumor removal can be performed successfully, resulting in good hearing performance. A slim modiolar electrode can be placed stably at the modiolus after schwannoma removal.

Cochlear implantation: an effective modality for hearing restoration following vestibular schwannoma resection

PURPOSE OF REVIEW

Preservation of hearing is one of the tenets of vestibular schwannoma management. In recent years, cochlear implants have been employed with increasing use in patients who have suffered profound sensorineural hearing loss due to the natural history of vestibular schwannoma or due to injury to neurovascular anatomy at time of surgical resection.

RECENT FINDINGS

Cochlear implantation has been found to be an effective modality for hearing restoration following vestibular schwannoma. Simultaneous cochlear implantation has been employed by an increased number of centers around the world and has been shown to provide restoration of open set speech perception and return of binaural hearing. Ongoing use of electrically evoked auditory brainstem response (ABR) has improved our detection of viable cochlear nerves and provided insight into those who would benefit from this procedure. Finally, minimally invasive approaches to the internal auditory canal and intralabyrinthine tumors have been described. These methods frequently employ simultaneous cochlear implantation and have emphasized that hearing preservation remains possible with surgical excision despite the location of the tumor.

SUMMARY

Cochlear implantation is an effective modality for hearing restoration following vestibular schwannoma excision.

Challenges of Cochlear Implantation in Intralabyrinthine Schwannoma Patients: Surgical Procedures and Auditory Outcome

Intralabyrinthine schwannoma (ILS) is a rare benign tumor of the inner ear potentially causing unilateral sensorineural hearing loss and vertigo. This study evaluated the outcome of one surgical session comprising microsurgical ILS resection and cochlear implantation in terms of surgical feasibility, complications, and auditory outcome. Ten clinically and histologically confirmed ILS patients included in this study (three women and seven men; mean age 56.4 ± 8.6) underwent surgery between July 2015 and February 2020. Eight patients had intracochlear tumor location; the remaining two had vestibulocochlear and intravestibular ILS. One of the three following methods was used for tumor removal: an extended cochleostomy, subtotal cochleoectomy, or a translabyrinthine approach. Although negligible improvement was observed in two of the patients, two patients were lost to follow-up, and one opted out from using CI, the speech perception of the five remaining ILS patients improved as per the Freiburg Monosyllable Test (FMT) from 0% before surgery to 45– 50% after the implantation. Our study supports the presented surgical approach’s feasibility and safety, enabling tumor removal and hearing restoration shortly after surgery.

Quality of Life Following Cochlear Implantation in Patients With Menière's Disease

Background: Menière's disease (MD) is a disorder characterized by auditory and vestibular dysfunction that significantly deteriorates patients' quality of life (QoL). In addition to the management of vestibular symptoms, some patients with bilateral hearing loss meet criteria for cochlear implantation (CI).

Objectives: (1) To assess hearing results and QoL outcomes following CI in patients with MD. (2) To compare these results to a matched control group of patients who had undergone CI. (3) To analyse differences in MD patients who have undergone simultaneous or sequential labyrinthectomy or previous neurectomy.

Methods: A retrospective analysis of a study group of 18 implanted patients with MD and a matched control group of 18 implanted patients without MD, who had CI at a tertiary referral center. Hearing and speech understanding were assessed via pure-tone audiometry (PTA) and disyllabic perception tests in quiet. QoL was assessed via the Nijmegen Cochlear Implant Questionnaire (NCIQ), the Glasgow Benefit Inventory (GBI), the Speech, Spatial and Qualities of Hearing Scale (SSQ₁₂), and the Hearing Implant Sound Quality Index (HISQUI₁₉). The impact of MD ablative surgeries was analyzed in the study group (MD group).

Results: Mean pre-operative PTA thresholds were significantly lower in the MD group (103 vs. 121 dB). A significant improvement in hearing outcomes was observed following CI in both groups (p < 0.001), with a maximum Speech Discrimination Score of 64 and 65% disyllables at 65 dB for the MD and control group, respectively. Subjective outcomes, as measured by the NCIQ, GBI, SSQ₁₂, and HISQUI₁₉ did not significantly differ between groups. In the MD group, despite achieving similar hearing results, QoL outcomes were worse in patients who underwent simultaneous CI and labyrinthectomy compared to the rest of the MD group. Post-operative NCIQ results were significantly better in patients who had undergone a previous retrosigmoid neurectomy when compared to those who had undergone only CI surgery in the subdomains “basic sound perception” (p = 0.038), “speech” (p = 0.005), “activity” (p = 0.038), and “social interactions” (p = 0.038).

Conclusion: Patients with MD and severe hearing loss obtain hearing results and QoL benefits similar to other CI candidates. Delayed CI after labyrinthectomy or vestibular neurectomy can be performed with similar or better results, respectively, to those of other cochlear implanted patients. Patients who undergo simultaneous CI and labyrinthectomy may achieve similar hearing results but careful pre-operative counseling is needed.

Surgical Labyrinthectomy and Cochlear Implantation in Menière's Disease

OBJECTIVE

The aim of this study was to analyze the results of labyrinthectomy and cochlear implantation (CI) on hearing, vertigo, and tinnitus and evaluate the adequacy of labyrinthectomy and CI for the treatment of end stage Menière's Disease (MD).

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

Charts of 22 patients undergoing labyrinthectomy and CI in the same ear for intractable vertigo and hearing loss with both preoperatory and postoperatory documentation available, were reviewed.

INTERVENTION(S)

Therapeutic.

MAIN OUTCOME MEASURE(S)

Auditory outcomes were assessed with pure tone and speech audiometry, and compared with the preoperatory audiometric evaluation. Dizziness was graded according to the Dizziness Handicap Inventory Questionnaire (DHI). Tinnitus outcomes were assessed by the tinnitus handicap inventory (THI).

RESULTS

Post-CI pure tone average had a statistically significant improvement (p = 0.035, paired t test). Speech audiometry resulted in a non-statistically significant speech discrimination score variation (p = 0.056, paired t test). Postoperatory THI had a statistically significant variation (p = 0.0001, paired t test). Sixty seven per cent of the patients had complete resolution of the vestibular symptoms in their operated ear, however, patients over 70 years old had significantly more failures as evinced by the postoperative DHI (p = 0.0109, Fisher's exact test).

CONCLUSIONS

Patients affected by end stage MD or secondary MD, with vertigo and severe hearing loss can successfully undergo labyrinthectomy and CI. Caution should be reserved in elderly patients for a risk of persistent instability. The CI confers significant benefit in hearing rehabilitation and tinnitus suppression.

Cochlear Implantation in Meniere's Disease: A Systematic Review and Meta-Analysis

OBJECTIVES/HYPOTHESIS

Meniere's disease (MD) is a debilitating condition characterized by hearing loss, vertigo, and tinnitus. The objective of this study was to systematically investigate outcomes in MD after cochlear implantation (CoI), with and without labyrinthectomy.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic review of articles in Medline and Embase was performed to identify all studies of patients with MD who underwent CoI. This analysis evaluates outcomes of speech recognition, pure tone audiometry, vertigo, tinnitus, and quality of life.

RESULTS

Of 321 studies identified, 37 were included, involving 216 patients. Mean age at implantation was 61.4 years (range 27-85 years) with average length of follow-up at 1.7 years (range 0-9 years). Forty-four (20.4%) patients underwent labyrinthectomy. Meta-analysis demonstrated significant improvements in audiometric outcomes following CoI. There was a statistically significant improvement in Hearing in Noise Test performance, with a mean difference improvement of 44.7 (95% confidence interval [CI] [8.8, 80.6]) at 6 months and 60.1 (95% CI [35.3, 85.0]) at 12 months. The Freiburger Monosyllabic Test (FMT) and Consonant-Nucleus-Consonant (CNC) also improved significantly, with mean difference improvements of 46.2 (95% CI [30.0, 62.4]) for FMT and 19.3 (95% CI [8.1, 30.4]) for CNC. There was a statistically significant decrease in tinnitus, as measured by a mean difference reduction of 48.1 (95% CI [1.0, 95.2]) in the Tinnitus Handicap Index.

CONCLUSIONS

CoI with and without simultaneous labyrinthectomy is a viable treatment option for patients with MD, yielding high rates of tinnitus suppression and vertigo control. Post-CoI MD patients demonstrate similar postoperative speech perception outcomes to non-MD implant recipients. Laryngoscope, 131:1845-1854, 2021.

Options and strategies for hearing restoration in pediatric neurofibromatosis type 2

PURPOSE

In this article, we will review the mechanisms and natural history of hearing loss in neurofibromatosis type 2 (NF2) and discuss the hearing outcomes with different rehabilitation options.

METHODS

Review of the published literature.

RESULTS

NF2 is a rare autosomal dominant syndrome characterized by vestibular schwannomas and other intracranial and spinal tumors. Bilateral vestibular schwannomas are the hallmark of the disease which occur in 90 to 95% of the patients. As a result, hearing loss will eventually occur in almost all NF2 patients. Deafness can occur from tumor progression or from treatment of vestibular schwannomas and is among the most debilitating aspects of NF2. A number of surgical and non-surgical rehabilitation options are available for these patients including cochlear and auditory brainstem implants. The audiologic outcomes with surgical rehabilitation options have been variable but most patients are able to achieve sound awareness and benefit from auditory cues in lip reading.

CONCLUSION

Early identification and treatment of NF2 patients can help in achieving better hearing outcomes in the pediatric population. An increasing number of NF2 patients are receiving open set word understanding with refinement in surgical techniques.

Evolving Criteria for Adult and Pediatric Cochlear Implantation

The indications for cochlear implantation have gradually expanded as advancements in technology have evolved, resulting in improved audiologic outcomes for both adult and children. There remains a significant underutilization of cochlear implant technology in the United States, and recognition of the potential benefits of cochlear implantation for non-traditional indications is critical for encouraging the evolution of candidacy criteria. Adult cochlear implantation candidacy has progressed from patients with bilateral profound sensorineural hearing loss (SNHL) to include patients with greater degrees of residual hearing, single-sided deafness and asymmetric hearing, and atypical etiologies of hearing loss (eg, vestibular schwannoma, Ménière's disease, and otosclerosis). Indications for pediatric cochlear implantation have similarly evolved from children with bilateral severe to profound SNHL to implanting children at a younger age, including those with residual hearing, asymmetric hearing loss, inner ear malformations, as well as cochlear nerve deficiency. In this editorial, the literature investigating cochlear implantation for nontraditional indications is reviewed with an aim to use the best available evidence to encourage the evolution of candidacy criteria.

Cochlear Implantation for Single-Sided Deafness: A New Treatment Paradigm

Unilateral severe-to-profound sensorineural hearing loss (SNHL), also known as single sided deafness (SSD), is a problem that affects both children and adults, and can have severe and detrimental effects on multiple aspects of life including music appreciation, speech understanding in noise, speech and language acquisition, performance in the classroom and/or the workplace, and quality of life. Additionally, the loss of binaural hearing in SSD patients affects those processes that rely on two functional ears including sound localization, binaural squelch and summation, and the head shadow effect. Over the last decade, there has been increasing interest in cochlear implantation for SSD to restore binaural hearing. Early data are promising that cochlear implantation for SSD can help to restore binaural functionality, improve quality of life, and may faciliate reversal of neuroplasticity related to auditory deprivation in the pediatric population. Additionally, this new patient population has allowed researchers the opportunity to investigate the age-old question "what does a cochlear implant (CI) sound like?."

Cochlear Patency After Translabyrinthine Vestibular Schwannoma Surgery

OBJECTIVES

To determine the temporal occurrence of fluid signal changes on T2-weighted magnetic resonance imaging (T2MRI) that occur in the cochlear lumen after translabyrinthine surgery.

STUDY DESIGN

Retrospective case control study.

SETTING

Tertiary referral neurotology center.

SUBJECTS AND METHODS

Seventy-one patients were identified who underwent translabyrinthine removal of a vestibular schwannoma between 2010 and 2014; of these 49 were included as they had postoperative T2 MRI at 6, 18, and 48 months available postsurgery. Magnetic resonance imaging scans were scored base on fluid signal changes within the cochlea.

RESULTS

In total, 147 magnetic resonance imaging scans were reviewed on 49 patients. In the cohort analysis 86% of patients showed evidence of fluid signal changes 48 months postoperatively. Ninety-five percent of patients who went on to demonstrate loss of fluid signal at 48 months had already shown changes at 6 months postsurgery. The majority of cochlea signal changes identified at 6 months were minor (72% Grade 1) while at 48 months this had progressed to severe (71% Grade 2 or 3). Of the patients with a normal cochlea at 6 months 78% maintained a normal cochlea to the 48-month scan.

CONCLUSION

Cochlear signal changes suggestive of fibrosis occurred in most patients following translabyrinthine removal of vestibular schwannoma. Given the early onset of cochlear fluid signal changes on T2MRI, and the progression of these changes on subsequence imaging, cochlear implantation would ideally need to be performed either simultaneous to translabyrinthine surgery or as an early second-stage procedure to maximize the chance of a successful electrode insertion, or one can consider a placeholder as well.

Cochlear implantation and auditory brainstem implantation in neurofibromatosis type 2

OBJECTIVES/HYPOTHESIS

To report a series of patients with neurofibromatosis type 2 (NF2), where each patient underwent both cochlear implantation and auditory brainstem implantation for hearing rehabilitation, and to discuss factors influencing respective implant success.

STUDY DESIGN

Retrospective case series.

METHODS

Ten NF2 patients with both cochlear implantations and auditory brainstem implantations were retrospectively reviewed. Speech testing for auditory brainstem implants (ABIs) and cochlear implants (CIs) was performed separately. Scores at last follow-up were obtained for Iowa vowels and consonants, Northwestern University Children's Perception of Speech (NU-CHIPS), and City University of New York (CUNY) sentences.

RESULTS

Mean age at time of implant was 37 years for cochlear implantation and 40 years for auditory brainstem implantation (P = .790, t test). Nine of 10 patients had a CI and ABI on contralateral sides, and one had both devices on the same side. Mean duration of deafness in the implanted ear was 4.3 years for both cochlear implantation and auditory brainstem implantation (P = .491, t test). Follow-up range was 1 to 28 years. CI performance on NU-CHIPS was 32% to 100%, and sound + lip-reading CUNY was 56% to 100%. Four patients experienced an eventual decline in CI function to unusable levels. ABI performance on NU-CHIPS was 40% to 80%, and sound + lip-reading CUNY was 38% to 94%. There was no notable decline in ABI function over time.

CONCLUSIONS

If the cochlear nerve is intact, cochlear implantation can be an effective strategy for hearing rehabilitation in NF2. However, a significant proportion experience a decline in CI performance related to growing vestibular schwannoma or tumor treatment. Auditory brainstem implantation remains the standard option for surgical hearing rehabilitation in NF2, but peak performance is generally lower than that achievable with cochlear implantation.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:2163-2169, 2018.

Recent surgical options for vestibular vertigo

Vertigo is not a well-defined disease but a symptom that can occur in heterogeneous entities diagnosed and treated mainly by otolaryngologists, neurologists, internal medicine, and primary care physicians. Most vertigo syndromes have a good prognosis and management is predominantly conservative, whereas the need for surgical therapy is rare, but for a subset of patients often the only remaining option. In this paper, we describe and discuss different surgical therapy options for hydropic inner ear diseases, Menière's disease, dehiscence syndromes, perilymph fistulas, and benign paroxysmal positional vertigo. At the end, we shortly introduce the most recent developments in regard to vestibular implants. Surgical therapy is still indicated for vestibular disease in selected patients nowadays when conservative options did not reduce symptoms and patients are still suffering. Success depends on the correct diagnosis and choosing among different procedures the ones going along with an adequate patient selection. With regard to the invasiveness and the possible risks due to surgery, in depth individual counseling is absolutely necessary. Ablative and destructive surgical procedures usually achieve a successful vertigo control, but are associated with a high risk for hearing loss. Therefore, residual hearing has to be included in the decision making process for surgical therapy.

Cochlear obliteration following a translabyrinthine approach and its implications in cochlear implantation

The most frequent sequelae following a translabyrinthine approach for vestibular schwannoma resection is complete hearing loss on the affected side. Such patients could benefit from a cochlear implant, provided that two essential requisites are met before surgery: a preserved cochlear nerve and a patent cochlea to accommodate the electrode array. The goal of our study is to determine the prevalence and extent of cochlear ossification following a translabyrinthine approach. Postoperative MRI of 41 patients were retrospectively reviewed. Patients were classified according to the degree of cochlear obliteration into three groups (patent cochlea, partially obliterated cochlea and totally obliterated cochlea). The interval between surgery and the first MRI was studied as well as its relationship with the rate of cochlear ossification. At first postoperative MRI (mean interval of 20 months), 78% of patients showed some degree of cochlear ossification. Differences were found in the time interval between surgery and first MRI for each group, showing a smaller interval of time the patent cochlea group (p > 0.05). When MRI was performed before the first year after surgery, a larger rate of patent cochlea was found (p > 0.05). The present study suggests that cochlear ossification is a time-depending process, whose grounds are still to be defined.

[Treatment and auditory rehabilitation of intralabyrinthine schwannoma by means of cochlear implants - German Version]

BACKGROUND

To date, the therapy of intralabyrinthine schwannoma consists mainly of a wait-and-see approach, completely ignoring auditory rehabilitation. Only a few single-case reports are as yet available on treatment with cochlear implants (CI).

AIM OF THE STUDY

This study aimed to assess the results of auditory rehabilitation after treatment with CI in a series of cases.

MATERIALS AND METHODS

The demographic findings, symptoms, and results of surgical therapy in 8 patients were evaluated in a retrospective analysis.

RESULTS

Prior to surgery, all patients presented with profound hearing loss and tinnitus. Episodic dizziness was reported by 3 patients. Among the patients, 4 had an intracochlear and 3 an intravestibular schwannoma, and a transmodiolar schwannoma was found in 1 patient. A total of 6 patients underwent treatment with CI. The results of auditory rehabilitation are favorable with open-set speech comprehension.

DISCUSSION

CI treatment following resection of an intralabyrinthine schwannoma is a promising option for auditory rehabilitation, even in single-sided deafness. This is a new treatment concept in contrast to the wait-and-scan policy. Expectant management appears justified only if the patient still has usable hearing.

Cochlear Implantation in Ménière's Disease With and Without Labyrinthectomy

OBJECTIVE

To investigate outcomes of cochlear implantation (CI) in patients with Ménière's disease (MD) with and without surgical labyrinthectomy.

STUDY DESIGN

Retrospective study.

SETTING

Multiple tertiary referral centers.

SUBJECTS

Thirty one ears from 27 patients (17 men, 10 women, aged 42-84) with CI in ipsilateral MD ear.

INTERVENTION

CI in ears with intact labyrinths (Group 1), CI with simultaneous surgical labyrinthectomy (Group 2), and CI sequential to surgical labyrinthectomy (Group 3).

MAIN OUTCOME MEASURE

Within-subject improvement on Bamford Kowal Bench test or City University of New York open set sentence tests.

RESULTS

Majority of ears achieved excellent open-set speech recognition by 12 months post-CI, irrespective of intervention group. Preoperative details including patient age and sex, implant, MD and previous intervention, and audiological test results did not significantly affect outcomes. Patients with MD undergoing CI only may experience vestibular dysfunction which may cause long-term concerns. Incidental finding was noted of eight ears with fluctuating symptoms in ipsilateral ear during 12-month period post-CI, with five of eight ears showing objective fluctuating impedances and mapping.

CONCLUSION

CI in MD can yield good hearing outcomes in all three groups and this is possible even after a long delay after labyrinthectomy. Bilateral MD patients are complex and prospective quality of life (QoL) measures would be beneficial in being better able to manage the vestibular outcomes as well as the audiological ones.

Cochlear Patency After Transmastoid Labyrinthectomy for Ménière's Syndrome

OBJECTIVE

Labyrinthectomy is considered the "gold standard" in the treatment of intractable vertigo attacks because of Ménière's Disease (MD) but sacrifices all residual hearing. Interest in auditory rehabilitation has lead to cochlear implantation in some patients. Concern remains that the cochlear lumen may fill with tissue or bone after surgery. This study sought to determine the incidence of obliteration of the cochlea after transmastoid labyrinthectomy.

STUDY DESIGN

Retrospective observational study.

SETTING

Tertiary referral center.

PATIENTS

Eighteen patients with intractable vertigo from MD who underwent surgery.

INTERVENTIONS

Transmastoid labyrinthectomy between 2008 and 2013. Cochleas were imaged with unenhanced, heavily T2-weighted magnetic resonance imaging (MRI).

MAIN OUTCOME MEASURE

Presence of symmetrical cochlear fluid signals on MRI.

RESULTS

There was no loss of fluid signal in the cochleas of operated ear compared with the contralateral, unoperated ear in any subject an average of 3 years (standard deviation [SD]: 1.2) after surgery. Five of 18 patients had the vestibule blocked with bone wax at the time of surgery. Blocking the vestibule with bone wax did not change the cochlear fluid signal.

CONCLUSION

The risk of cochlear obstruction after labyrinthectomy for MD is very low. The significance of this finding is that patients with MD who undergo labyrinthectomy will likely remain candidates for cochlear implantation in the labyrinthectomized ear long after surgery if this becomes needed. Immediate cochlear implantation or placement of a cochlear lumen keeper during labyrinthectomy for MD is probably not necessary.

Translabyrinthine vestibular schwannoma resection with simultaneous cochlear implantation

OBJECTIVES

(1) Report a rare case of translabyrinthine resection of a sporadic vestibular schwannoma (VS) and concurrent cochlear implantation (CI). (2) Discuss pre-, intra-, and post-operative considerations in this unique patient population. (3) Describe surgical and audiologic outcomes reported in this population.

METHODS

Case report and review of the literature. PubMed search 'Cochlear Implantation'[Mesh] AND ('Neuroma, Acoustic'[Mesh] OR 'VESTIBULAR SCHWANNOMA'[All Fields] OR 'SCHWANNOMA'[All Fields]) limited to humans and English language. Returned 64 search results, abstracts and references of relevant papers reviewed.

RESULTS

A 75-year-old male with longstanding history of slowly progressive severe hearing loss and tinnitus presented for evaluation of worsening imbalance, vertigo, and nausea. Workup revealed a 7 mm right intracanalicular mass on MRI concerning for vestibular schwannoma. Audiogram showed bilateral, symmetric, severe-to-profound sensorineural hearing loss, with poor open-set speech comprehension while bilaterally aided. He underwent successful concurrent right translabyrinthine resection of his VS with complete preservation of the cochlear nerve and uncomplicated cochlear implantation.

DISCUSSION

Literature review revealed few previous reports of simultaneous VS and CI. The vast majority of these were in patients with neurofibromatosis Type 2 in whom auditory outcomes were poor. This patient represents one of the few cases of concurrent translabyrinthine tumor removal and CI for a spontaneous VS.

CONCLUSION

Single-stage cochlear implantation and translabyrinthine tumor resection is a feasible and safe option to consider for auditory rehabilitation in rare situations.

Factors Influencing Cochlear Patency after Translabyrinthine Surgery

Objective

To determine predictive factors for cochlear obliteration after translabyrinthine surgery for vestibular schwannoma.

Study Design

Case series with chart review.

Setting

Neurotology referral center.

Subjects and Methods

In total, 345 charts were reviewed, resulting in 103 patients who underwent translabyrinthine surgery between January 2010 and July 2015 and had postoperative magnetic resonance imaging (MRI) for review. Surveillance MRI performed after translabyrinthine resection of vestibular schwannomas was reviewed. Heavily T2-weighted MRI obtained an average of 21.8 months after surgery was reviewed to assess cochlear patency. Tumor size, preoperative audiograms, and MRI cochlear fluid-attenuated inversion recovery (FLAIR) intensity were compared between patients with retained cochlear patency and those without.

Results

Fifty-four percent of patients retained cochlear patency after translabyrinthine surgery. Tumor size did not differ statistically between the 2 groups. There was no statistically significant difference in speech reception thresholds, pure-tone average, or word recognition scores between patent and nonpatent groups. Preoperative MRI FLAIR intensity did not differ between groups.

Conclusions

More than half of patients retain cochlear patency after translabyrinthine vestibular schwannoma surgery. Cochlear patency is required for cochlear implant in patients with unilateral deafness. Preoperative tumor size, hearing performance, and intensity on MRI FLAIR do not predict cochlear patency. To prevent loss of opportunity for cochlear implantation, simultaneous implantation and cochlear lumen keeper placement are options.

Sensitivity of the cochlear nerve to acoustic and electrical stimulation months after a vestibular labyrinthectomy in guinea pigs

Single-sided deafness patients are now being considered candidates to receive a cochlear implant. With this, many people who have undergone a unilateral vestibular labyrinthectomy for the treatment of chronic vertigo are now being considered for cochlear implantation. There is still some concern regarding the potential efficacy of cochlear implants in these patients, where factors such as cochlear fibrosis or nerve degeneration following unilateral vestibular labyrinthectomy may preclude their use. Here, we have performed a unilateral vestibular labyrinthectomy in normally hearing guinea pigs, and allowed them to recover for either 6 weeks, or 10 months, before assessing morphological and functional changes related to cochlear implantation. Light sheet fluorescence microscopy was used to assess gross morphology throughout the entire ear. Whole nerve responses to acoustic, vibrational, or electrical stimuli were used as functional measures. Mild cellular infiltration was observed at 6 weeks, and to a lesser extent at 10 months after labyrinthectomy. Following labyrinthectomy, cochlear sensitivity to high-frequency acoustic tone-bursts was reduced by 16 ± 4 dB, vestibular sensitivity was almost entirely abolished, and electrical sensitivity was only mildly reduced. These results support recent clinical findings that patients who have received a vestibular labyrinthectomy may still benefit from a cochlear implant.