Monitoring Cochlear Nerve Action Potential for Hearing Preservation in Medium/Large Vestibular Schwannoma Surgery: Tips and Pitfalls.

The diagnosis of large vestibular schwannomas (VS) with retained useful hearing has become increasingly common. Preservation of facial nerve (FN) function has improved using intraoperative EMG monitoring, hearing preservation remains challenging, with the recent use of cochlear nerve action potential (CNAP) monitoring. This prospective longitudinal series of VS with useful hearing operated on using a retrosigmoid approach included 37 patients with a mean largest extrameatal VS. diameter of 25 ± 8.7 mm (81% of Koos stage 4). CNAP was detected in 51% of patients, while auditory brainstem responses (ABR) were present in 22%. Patients were divided into two groups based on the initial intraoperative CNAP status, whether it was present or absent. FN function was preserved (grade I-II) in 95% of cases at 6 months. Serviceable hearing (class A + B) was preserved in 16% of the cases, while 27% retained hearing with intelligibility (class A-C). Hearing with intelligibility (class A-C) was preserved in 42% of cases when CNAP could be monitored in the early stages of VS resection versus 11% when it was initially absent. Changes in both the approach to the cochlear nerve and VS resection are mandatory in preserving CNAP and improve the rate of hearing preservation.

Recurrent Benign Paroxysmal Positional Vertigo in DFNB16 Patients with Biallelic STRC Gene Deletions.

OBJECTIVE: Deletions of STRC gene (DFNB16) account for 12% of isolated congenital mild to moderate hearing loss (HL). In mice, the stereocilin protein, encoded by STRC , is present in the vestibular kinocilium embedded in the otoconial membrane of the utricular macula. Despite this, effects on vestibular function have not been widely investigated. The aim of this study was to investigate the prevalence of benign paroxysmal positional vertigo (BPPV) in a cohort of DFNB16 patients. STUDY DESIGN: Observational descriptive epidemiological study. SETTING: Single-center study, in a tertiary referral center. PATIENTS: Older than 5 years, with a genetic diagnosis of HL related to biallelic STRC gene deletions, diagnosed between 2015 and 2021. INTERVENTION: Patients or their parents were interviewed to determine whether they had experienced vertigo or episodes of BPPV. MAIN OUTCOME MEASURE: Criteria were at least five acute episodes of rotatory vertigo, each lasting less than 1 minute, episodes triggered by changes in specific head position, and an absence of neurological symptoms. RESULTS: Sixty-four patients having mild (33%) to moderate (66%) HL were included. Median age was 15 years (range, 6-48 yr). Prevalence of BPPV was 39% (25 of 64). Median age of first onset was 13 years (range, 3-18 yr). CONCLUSIONS: This study showed recurrent BPPV and early age of onset in patients with biallelic STRC gene deletions. BPPV may be associated with the HL phenotype in patients with STRC gene deletions. It is important to inform patients and families of this potential risk such that appropriate management can be proposed.

Features of Mild-to-Moderate COVID-19 Patients With Dysphonia.

INTRODUCTION: To explore the prevalence of dysphonia in European patients with mild-to-moderate COVID-19 and the clinical features of dysphonic patients. METHODS: The clinical and epidemiological data of 702 patients with mild-to-moderate COVID-19 were collected from 19 European Hospitals. The following data were extracted: age, sex, ethnicity, tobacco consumption, comorbidities, general, and otolaryngological symptoms. Dysphonia and otolaryngological symptoms were self-assessed through a 4-point scale. The prevalence of dysphonia, as part of the COVID-19 symptoms, was assessed. The outcomes were compared between dysphonic and nondysphonic patients. The association between dysphonia severity and outcomes was studied through Bayesian analysis. RESULTS: A total of 188 patients were dysphonic, accounting for 26.8% of cases. Females developed more frequently dysphonia than males (P = 0.022). The proportion of smokers was significantly higher in the dysphonic group (P = 0.042). The prevalence of the following symptoms was higher in dysphonic patients compared with nondysphonic patients: cough, chest pain, sticky sputum, arthralgia, diarrhea, headache, fatigue, nausea, and vomiting. The severity of dyspnea, dysphagia, ear pain, face pain, throat pain, and nasal obstruction was higher in dysphonic group compared with nondysphonic group. There were significant associations between the severity of dysphonia, dysphagia, and cough. CONCLUSION: Dysphonia may be encountered in a quarter of patients with mild-to-moderate COVID-19 and should be considered as a symptom list of the infection. Dysphonic COVID-19 patients are more symptomatic than nondysphonic individuals. Future studies are needed to investigate the relevance of dysphonia in the COVID-19 clinical presentation.

Atraumatic Insertion of a Cochlear Implant Pre-Curved Electrode Array by a Robot-Automated Alignment with the Coiling Direction of the Scala Tympani.

INTRODUCTION: Electrode array translocation is an unpredictable event with all types of arrays, even using a teleoperated robot in a clinical scenario. We aimed to compare the intracochlear trauma produced by the HiFocus™ Mid-Scala (MS) electrode array (Advanced Bionics, Valencia, CA, USA) using a teleoperated robot, with an automated robot connected to a navigation system to align the pre-curved tip of the electrode array with the coiling direction of the scala tympani (ST). METHODS: Fifteen freshly frozen temporal bones were implanted with the MS array using the RobOtol® (Collin, Bagneux, France). In the first group (n = 10), the robot was teleoperated to insert the electrode array into the basal turn of the ST under stereomicroscopic vision, and then the array was driven by a slow-speed hydraulic insertion technique with an estimated placement of the pre-curved electrode tip. In the second group (n = 5), 3 points were obtained from the preoperative cone-beam computed tomography: the 2 first defining the ST insertion axis of the basal turn and a third one at the center of the ST at 270°. They provided the information to the automated system (RobOtol® connected with a navigation system) to automatically align the electrode array with the ST insertion axis and to aim the pre-curved tip toward the subsequent coiling of the ST. After this, the electrode array was manually advanced. Finally, the cochleae were obtained and fixed in a crystal resin, and the position of each electrode was determined by a micro-grinding technique. RESULTS: In all cases, the electrode array was fully inserted into the cochlea and the depth of insertion was similar using both techniques. With the teleoperated robotic technique, translocations of the array were observed in 7/10 insertions (70%), but neither trauma nor array translocation occurred with automated robotic insertion. CONCLUSION: We have successfully tested an automated insertion system (robot + navigation) that could accurately align a pre-curved electrode array to the axis of the basal turn of the ST and its subsequent coiling, which reduced intracochlear insertion trauma and translocation.

Intraoperative facial nerve electromyography parameters to optimize postoperative facial nerve outcome in patients with large unilateral vestibular schwannoma.

BACKGROUND: Decision-making for large sporadic vestibular schwannomas (VS) resection guided by the intraoperative change in supramaximal facial nerve (FN) amplitude and latency response to optimize post-operative FN outcome. METHODS: Prospectively study of 43 patients, from January to December 2018, of large sporadic VS with preoperative normal FN function at our center. Tumors were removed through retrosigmoid (81%) or translabyrinthine (19%) approaches with FN monitoring. Intraoperative pre- and post-VS resection supramaximal (2 mA) amplitude and latency responses at the proximal FN root were recorded. RESULTS: Total, near-/subtotal VS resections (TR, NTR, STR) were achieved in 51%, 38%, and 11% of tumors, respectively, guided by no more than 40% decrease in supramaximal amplitude. Pre- and post-resection supramaximal amplitude and latency responses were lower and longer, respectively, in NTR+STR than in TR. At day 8, FN function was grade I-II in 77% of patients and grade III-V in 23%, and after 6 months, it was in grade I-II in 95% and grade III in 5%, and there was no significant difference between TR and NTR+STR. Facial palsy occurred in older patients and in the case of severe FN adhesion. At day 8, pre- and post-resection supramaximal amplitude but not latency responses were different between FN grade III-V and grade I-II. Serviceable hearing was preserved in 28% of large VS. CONCLUSIONS: Intraoperative FN monitoring guided VS resection in large VS so that 49% retained some residual tumor. Accordingly, 95% good postoperative FN function and significant hearing preservation were achieved after 6 months.

Metachronous Bilateral Vestibular Schwannomas.

Bilateral vestibular schwannoma (BVS) is the hallmark of neurofibromatosis type 2 (NF2), both of them being present at diagnosis. We report four cases of metachronous BVS, a contralateral intracanalicular vestibular schwannomas (VS) being visible 2 to 13 years after resection of a unilateral VS. NF2 workup was negative except in one case where two NF2 gene mutations were found in tumor analysis. These cases raise the questions of whether the contralateral VS occurred by chance and how to manage it on the only hearing ear. Otologists should be aware of this rare eventuality for decision making of the first unilateral VS. Laryngoscope, 131:E250-E254, 2021.

Management of sporadic vestibular schwannoma with contralateral nonserviceable hearing.

OBJECTIVES/HYPOTHESIS: To outline a possible decision-making process for sporadic vestibular schwannoma (VS) with contralateral nonserviceable hearing at diagnosis. STUDY DESIGN: Retrospective case series. METHODS: Diagnosed VS was studied in a tertiary referral center from 1995 to 2013. RESULTS: Twenty-eight patients were included, with a mean follow-up of 6.9 years (range = 0.5-20 years). Ten were stage 1, 10 were stage 2, five were stage 3, and three were stage 4. Ipsilateral hearing levels were A (n = 3), B (n = 10), C (n = 7) and D (n = 8) American Academy of Otolaryngology-Head and Neck Surgery classification. Contralateral hearing levels were C (n = 11) and D (n = 17). Initial VS management included surveillance (n = 12) or surgery (n = 16), and four patients were later treated with surgery (n = 3) or stereotactic irradiation (n = 1). Hearing was improved by hearing aids and/or etiological treatment (n = 8), restored by contralateral (n = 15) or ipsilateral (n = 4) cochlear implants (CIs), or ipsilateral auditory brainstem implants (ABIs) (n = 3). Finally, 18 CIs were active daily; 14 of them presented high or moderate benefit with mean open-set dissyllabic word scores (WRS) of 58.1% and sentence recognition scores (SRS) of 69.7%, but only one ABI was still active (WRS of 70% and SRS of 87% with lip reading). CONCLUSIONS: When early removal of VS was not necessary, contralateral CI or etiological treatment for hearing loss might be recommended initially. Ipsilateral CI is proposed, whereas VS should be operated on if previous hearing restoration was not successful. ABI should be reserved for the rare cases where a contralateral CI could not be implanted or the cochlear nerve was sectioned during VS removal. LEVEL OF EVIDENCE: 3 Laryngoscope, 130:E407-E415, 2020.

NF2-Related Intravestibular Schwannomas: Long-Term Outcomes of Cochlear Implantation.

OBJECTIVE: Intravestibular schwannomas (IVS) are uncommon tumors in Neurofibromatosis type 2 (NF2) and are mainly associated with multiple internal auditory meatus (IAM) and cerebellopontine angle (CPA) tumors. They usually induce profound hearing loss which can be rehabilitated by cochlear implantation (CI). The aim of this study was to analyze the long-term outcomes of CI during the unpredictable evolution of NF2 disease. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Three adults with neurofibromatosis type 2 and intravestibular schwannomas, and who were cochlear implant recipients. INTERVENTIONS: Periodic radiologic follow-up, tumor resection, and hearing rehabilitation. MAIN OUTCOME MEASURES: Audiological evolution, tumor evolution, surgical outcome, cochlear implant outcome. RESULTS: Three NF2 patients (mean age at diagnosis, 26.3 ±â€Š3.2 yr) were identified with IVS in the period between 2000 and 2017. IVS were first observed by serial MRI and profound hearing loss occurred in this ear after 4 ±â€Š1.5 years of follow-up. IVS were removed via a translabyrinthine approach, and ipsilateral cochlear implantations were simultaneously performed. In two patients, large contralateral CPA tumors had previously been removed without hearing preservation, whereas in the third patient, a small, growing contralateral VS was excised via a retrosigmoid approach 6 months after IVS removal/cochlear implantation with serviceable hearing preservation. In all cases, CI provided good hearing outcomes. In two cases, hearing outcomes were even better for more than 5 years when ipsilateral intracanalicular vestibular schwannomas were removed in either the same or subsequent procedures. CONCLUSIONS: Rehabilitation of hearing with CI provides a favorable long-term outcome in patients with NF2-related IVS which could be altered by the occurrence of other intracanalicular and/or CPA NF2-related tumors.

Bioactive glass granules for mastoid and epitympanic surgical obliteration: CT and MRI appearance.

PURPOSE: To evaluate the appearance of mastoid and epitympanic obliteration using S53P4 bioactive glass (BG) granules in high-resolution computed tomography (HRCT) and MRI. MATERIALS AND METHODS: Patients undergoing mastoid and epitympanic obliteration between May 2013 and December 2015 were prospectively included in an uncontrolled clinical study. All patients underwent a temporal HRCT scan 1 year after surgery, aimed at evaluating the attenuation, homogeneity, and osseointegration of the BG granules, as well as the ventilation of the middle ear and the volume of the obliterated paratympanic spaces. If a cholesteatoma was found during surgery, additional MRI, including at least pre- and post-contrast T1-weighted, T2-weighted, and axial non-echo-planar diffusion-weighted (DW) sequences, was performed 1 year after surgery, to study the normal signal of the BG granules and the presence of residual cholesteatoma and/or other temporal bone pathologies. RESULTS: Seventy cases were included. On 1-year HRCT, the mean attenuation of the BG granules was 888.34 ± 166.10 HU. The obliteration was found to be mostly homogeneous with partial osseointegration. The appearance of the BG granules having a low-intensity signal in T2-weighted imaging and DW MRI was always different from the appearance of cholesteatoma. A longer follow-up has shown no attenuation or signal modification of the BG granules compared with the 1-year imaging. CONCLUSION: Radiological follow-up of patients operated on with mastoid and epitympanic obliteration using BG granules is effective using both HRCT and MRI. A cholesteatoma and/or other potential complications could easily be detected due to the specific radiological appearance of the BG granules. KEY POINTS: • The appearance of mastoid and epitympanic obliteration by S53P4 bioactive glass (BG) granules on high-resolution computed tomography (HRCT) scans was homogeneous with an attenuation significantly higher than the attenuation of cholesteatoma and lower than mastoid bone attenuation. • The granules have a low-intensity signal on non-echo-planar diffusion-weighted sequences and on T2-weighted images and present contrast enhancement allowing the differential diagnosis with cholesteatoma and effective for the detection of other underlying temporal bone pathologies. • The volume and radiological appearance of the obliteration appear to be stable with time.

Preoperative Assessment of Cervical Vestibular Evoked Myogenic Potentials (cVEMPs) Help in Predicting Hearing Preservation After Removal of Vestibular Schwannomas Through a Middle Fossa Craniotomy.

OBJECTIVE: To determine whether cervical vestibular evoked myogenic potentials (cVEMPs) are predictive of hearing preservation in patients undergoing vestibular schwannoma removal through middle fossa craniotomy approach. STUDY DESIGN: Retrospective case study. SETTING: Tertiary referral center. PATIENTS: Eighteen patients who underwent a middle fossa craniotomy for vestibular schwannoma (stage I or II of Koos classification) with attempted hearing preservation from January 2008 to February 2016 were retrospectively reviewed. INTERVENTION: Pre-surgical cVEMPs test, videonystagmography (caloric test), and magnetic resonance imaging (MRI) as well as a pre- and post-surgical audiometry test. MAIN OUTCOME MEASURES: cVEMPs parameters including amplitude asymmetry ratio (AR), P13, and N23 latencies and peak-to-peak amplitude between P13 and N23 waves were calculated. Hearing data were classified according to the AAO-HNS hearing classes. The nerve of origin of the tumor was specified during surgery and the largest tumor diameter was measure on MRI axial plane on T2-CISS weighed images. RESULTS: Preoperative amplitude asymmetry ratio was lower (n = 15, Mann-Whitney U test, p < 0.001) in the group with postoperative hearing preservation (n = 11) compared with the group with postoperative hearing preservation failure (n = 4). The positive predictive value of an AR less than 24% to assess postoperative hearing preservation is 91.6%. Tumor size and localization were not correlated with cVEMPs, nor with caloric testing in this group of small-sized intracanalicular vestibular schwannomas. CONCLUSIONS: Our data suggest that cVEMPs may help predict hearing preservation outcome in vestibular schwannoma surgery via the middle fossa craniotomy approach.