Umbilical Cord Mesenchymal Stromal Cell-Derived Exosomes Rescue the Loss of Outer Hair Cells and Repair Cochlear Damage in Cisplatin-Injected Mice.

Umbilical cord-derived mesenchymal stromal cells (UCMSCs) have potential applications in regenerative medicine. UCMSCs have been demonstrated to repair tissue damage in many inflammatory and degenerative diseases. We have previously shown that UCMSC exosomes reduce nerve injury-induced pain in rats. In this study, we characterized UCMSC exosomes using RNA sequencing and proteomic analyses and investigated their protective effects on cisplatin-induced hearing loss in mice. Two independent experiments were designed to investigate the protective effects on cisplatin-induced hearing loss in mice: (i) chronic intraperitoneal cisplatin administration (4 mg/kg) once per day for 5 consecutive days and intraperitoneal UCMSC exosome (1.2 µg/µL) injection at the same time point; and (ii) UCMSC exosome (1.2 µg/µL) injection through a round window niche 3 days after chronic cisplatin administration. Our data suggest that UCMSC exosomes exert protective effects in vivo. The post-traumatic administration of UCMSC exosomes significantly improved hearing loss and rescued the loss of cochlear hair cells in mice receiving chronic cisplatin injection. Neuropathological gene panel analyses further revealed the UCMSC exosomes treatment led to beneficial changes in the expression levels of many genes in the cochlear tissues of cisplatin-injected mice. In conclusion, UCMSC exosomes exerted protective effects in treating ototoxicity-induced hearing loss by promoting tissue remodeling and repair.

Sudden Otovestibular Dysfunction in 3 Metastatic Melanoma Patients Treated With Immune Checkpoint Inhibitors.

Immune-related adverse events have been described in 86%-96% of high-risk melanoma patients treated with immune checkpoint inhibitors (ICI), while in 17%-59% of cases these are classified as severe or even life-threatening. The most common immune-related adverse events include diarrhea, fatigue, hypothyroidism, and hepatitis. Bilateral uveitis and unspecific vertigo have been described in 1% of cases, respectively, in the pivotal studies of ICIs, but the affection of the vestibule-cochlear system has not been reported before. In this case series, we present 3-stage IV melanoma patients with sudden onset of otovestibular dysfunction (hearing loss and vestibulopathy), partly combined with uveitis because of ICIs. We describe detailed diagnostic work-up and therapeutic interventions and discuss possible pathogenic mechanisms of this rare and disabling event.

Bilateral Hearing Loss and Unilateral Cochlear Ossification in a Patient With Chronic Myelogenous Leukemia.

Bilateral sensorineural deafness and unilateral cochlear ossification have rarely been described in patients with chronic myeloid leukemia (CML). A 21-year-old man presented to a hospital with right-sided sudden hearing loss and tinnitus. He was diagnosed with CML. Five days later, sudden hearing loss appeared in the other ear. Abnormality of the right-sided inner ear structure was revealed by preoperative magnetic resonance imaging; honeycomb-like cochlear ossification was observed during cochlear implant surgery in the right ear. The patient's auditory performance exhibited significant improvement after bilateral cochlear implantation in our hospital. Hematological disorders must be considered in patients with sensorineural hearing loss. Cochlear implantation is feasible in patients with CML who exhibit sensorineural deafness, but cochlear ossification should be carefully evaluated by means of preoperative imaging examinations.

Cochlear Patency after Translabyrinthine and Retrosigmoid Vestibular Schwannoma Surgery.

OBJECTIVES: To assess the incidence and onset of cochlear obliteration after translabyrinthine and retrosigmoid vestibular schwannoma surgery. MATERIALS AND METHODS: We retrospectively identified a consecutive series of eighty ears in eighty vestibular schwannoma patients who were treated via a translabyrinthine or retrosigmoid approach by a single neuro-otological surgical team in a tertiary referral center from May 2011 to January 2018. Postoperative, high- resolution T2-weighted turbo spin echo three-dimensional magnetic resonance (MR) images of the posterior fossa were evaluated at the level of the membranous labyrinth and internal auditory canal. Perilymphatic patency of the vestibule, basal, and apical cochlear turns were scored and classified as patent, hypointense, partially obliterated, or completely obliterated. RESULTS: Twenty-five vestibular schwannomas were treated with surgery via a translabyrinthine approach, and fifty-five were treated using a retrosigmoid approach; of these, 8% and 65%, respectively, showed no signs of perilymphatic alterations in the basal or apical turns, while 84% and 20%, respectively, showed partial or complete obliteration in the basal or apical turns with a mean postoperative interval of 127 and 140 days, respectively. All the patients who underwent multiple MR scans and had a completely patent perilymphatic system on the first postoperative scan remained patent during subsequent scans; 16% of the patients showed worsened perilymphatic appearance. The onset of cochlear obliteration occurred within 2-7 months in most translabyrinthine patients. CONCLUSION: These findings may support the need for simultaneous cochlear electrode or dummy implantation in translabyrinthine surgery. Second-stage implantation could be feasible in cases where a retrosigmoid approach is used; however, the implantation should be considered within the initial months to avoid cochlear obliteration. Findings on the first postoperative MR could indicate the need for intensified MR follow-up and may even predict the occurrence of cochlear obliteration.

Pattern of cochlear obliteration after vestibular Schwannoma resection according to surgical approach.

OBJECTIVES/HYPOTHESIS: To investigate the prevalence and course of cochlear obliteration according to microsurgical approach to inform clinical decision making regarding optimal timing of cochlear implantation. STUDY DESIGN: Retrospective radiologic review and chart review. METHODS: Patients who underwent microsurgical resection of vestibular schwannoma (VS) with a minimum of two available postoperative magnetic resonance imaging (MRI) scans were analyzed. The prevalence and timing of cochlear and labyrinthine obliteration was classified using relevant MRI sequences. RESULTS: MRI studies in 60 patients were analyzed: 20 translabyrinthine (TL), 20 retrosigmoid, and 20 middle fossa (MF) cases. The first and last postoperative MRI was obtained a median of 3.4 months (interquartile range (IQR), 3.0-3.7 months) and 35 months (IQR, 27-83 months) after surgery, respectively. At the time of the first postoperative MRI, 21 (35%) patients had partial basal turn obliteration, and none of the patients had complete basal turn obliteration. At the time of the last postoperative MRI, six (10%) patients had partial basal turn obliteration and 17 (28%) patients had complete basal turn obliteration. The pattern of partial or complete basal turn obliteration differed significantly among all three surgical approaches (P < .001). Specifically, the risk of partial or complete obliteration of the basal turn was highest in the TL cohort and lowest in the MF cohort. CONCLUSIONS: The prevalence and timing of cochlear obliteration after VS microsurgery varies significantly according to surgical approach. The risk of early and complete obliteration is highest in the TL group and lowest in the MF cohort. These data may inform clinical decision making regarding optimal timing of cochlear implantation in patients with advanced hearing loss after microsurgical resection. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:474-481, 2020.

Is there a relation between sudden sensorineural hearing loss and white matter lesions?

PURPOSE: Sudden sensorineural hearing loss (SSNHL) has similarities to conditions with vascular etiologies such as myocardial infarction and cerebral stroke. Thus, it could be considered as an early sign of a vascular disease and not only a specific local condition. Chronic hypoperfusion in the brain districts leads to a chronic ischemic damage, called cerebral small vessel disease (CSVD), detectable with brain magnetic resonance imaging (MRI). METHODS: The authors used CSVD to establish the presence of vascular risk factors in individuals with SSNHL and used the Fazekas score scale to classify them. RESULTS: Our study showed that individuals with SSNHL aged between 48 and 60 years have 26% more probability to have a Fazekas score higher than 1 compared to the general population. Individuals younger than 28 years showed a statistically significant negative correlation to have a Fazekas score higher than 0. The higher is the Fazekas score, the less is the probability of hearing recovery. The medium hearing-recovery probability is 46%. This decreases by 16% for every increase of score in the Fazekas scale. In the present study, the recovery probability decreased from 80% in individuals younger than 48 years with a score of 0 to 14% in individuals with a Fazekas scores of 3 and 4. CONCLUSIONS: The authors assessed a higher prevalence of CSVD compared to the general population in patients aged between 48 and 60 years with SSNHL. Moreover, they assessed that the presence of CSVD is related to a decreased probability of recovery, as it has already been demonstrated for stroke.

Cochlear patency following translabyrinthine vestibular schwannoma resection: implications for hearing rehabilitation.

OBJECTIVE: To examine when cochlear fibrosis occurs following a translabyrinthine approach for vestibular schwannoma resection, and to determine the safest time window for potential cochlear implantation in cases with a preserved cochlear nerve. METHODS: This study retrospectively reviewed the post-operative magnetic resonance imaging scans of patients undergoing a translabyrinthine approach for vestibular schwannoma resection, assessing the fluid signal within the cochlea. Cochleae were graded based on the Isaacson et al. system (from grade 0 - no obstruction, to grade 4 - complete obliteration). RESULTS: Thirty-nine patients fulfilled the inclusion criteria. The cochleae showed no evidence of obliteration in: 75 per cent of patients at six months, 38.5 per cent at one year and 27 per cent beyond one year. Most changes happened between 6 and 12 months after vestibular schwannoma resection, with cases of an unobstructed cochlear decreasing dramatically, from 75 per cent to 38.5 per cent, within this time. CONCLUSION: The progress of cochlear obliteration that occurred between 6 and 12 months following vestibular schwannoma resection indicates that the first 6 months provides a safer time window for cochlear patency.

Cochlear Erosion due to a Facial Nerve Schwannoma.

Facial nerve schwannomas are rare benign neoplasms. We report a case of a 60-year-old woman who initially presented with vestibular complaints. Magnetic resonance imaging (MRI) revealed a facial nerve schwannoma centered on the right geniculate ganglion extending in the labyrinthine segment. The patient consulted again after 2 months because she developed a sudden and severe right-sided sensorineural hearing loss. MRI showed no progression or pathological enhancement in the membranous labyrinth. A cone beam computed tomography (CT) of the temporal bone was performed and revealed a large erosion at the region of the geniculate ganglion in open communication with the middle turn of the cochlea. This case report demonstrates the importance of CT in facial nerve schwannomas for evaluating the impact on the surrounding structures.

Purinergic Signaling and Cochlear Injury-Targeting the Immune System?

Hearing impairment is the most common sensory deficit, affecting more than 400 million people worldwide. Sensorineural hearing losses currently lack any specific or efficient pharmacotherapy largely due to the insufficient knowledge of the pathomechanism. Purinergic signaling plays a substantial role in cochlear (patho)physiology. P2 (ionotropic P2X and the metabotropic P2Y) as well as adenosine receptors expressed on cochlear sensory and non-sensory cells are involved mostly in protective mechanisms of the cochlea. They are implicated in the sensitivity adjustment of the receptor cells by a K+ shunt and can attenuate the cochlear amplification by modifying cochlear micromechanics. Cochlear blood flow is also regulated by purines. Here, we propose to comprehend this field with the purine-immune interactions in the cochlea. The role of harmful immune mechanisms in sensorineural hearing losses has been emerging in the horizon of cochlear pathologies. In addition to decreasing hearing sensitivity and increasing cochlear blood supply, influencing the immune system can be the additional avenue for pharmacological targeting of purinergic signaling in the cochlea. Elucidating this complexity of purinergic effects on cochlear functions is necessary and it can result in development of new therapeutic approaches in hearing disabilities, especially in the noise-induced ones.

Intracochlear tPA infusion may reduce fibrosis caused by cochlear implantation surgery.

BACKGROUND: Experiments show that the extent of ongoing fibrotic change within the cochlea can be determined by the volume and pattern of bleeding within the first 24 h following cochlear implantation. Tissue-type plasminogen activator (tPA) is effective at reducing thrombus volume when administered both within and external to the systemic circulation. AIMS/OBJECTIVES: To determine if tPA delivered into the scala tympani immediately following implantation will reduce thrombus volume within the lower basal turn of the cochlea. MATERIALS AND METHODS: Guinea pigs were implanted with either 'soft' or 'hard' arrays and administered tPA or saline via an intra-cochlear infusion immediately after implantation. Hearing was checked prior to, and 2 weeks after implantation. Cochleae were then harvested and imaged. RESULTS: Animals implanted with 'soft' arrays had 4.2% less tissue response compared with animals implanted with 'hard' arrays. In animals receiving 'soft' arrays, tPA reduced the volume of tissue response (measured by the percentage of the lower basal turn of the scala tympani occupied by tissue response) compared with saline. CONCLUSIONS AND SIGNIFICANCE: tPA may be effective in reducing the overall volume of tissue response in routine 'soft' cochlear implantation and may have a greater effect in the event of significant surgical trauma.

Association of Tinnitus and Other Cochlear Disorders With a History of Migraines.

Importance: A headache is a symptom of a migraine, but not all patients with migraine have headaches. It is still unclear whether a migraine might increase the risk of cochlear disorders, even though a migraine does not occur concurrently with cochlear disorders. Objective: To investigate the risk of cochlear disorders for patients with a history of migraines. Design, Setting, and Participants: This study used claims data from the Taiwan Longitudinal Health Insurance Database 2005 to identify 1056 patients with migraines diagnosed between January 1, 1996, and December 31, 2012. A total of 4224 controls were also identified from the same database based on propensity score matching. Statistical analysis was performed from January 23, 1996, to December 28, 2012. Main Outcomes and Measures: The incidence rate of cochlear disorders (tinnitus, sensorineural hearing impairment, and/or sudden deafness) was compared between the cohorts by use of the Kaplan-Meier method. The Cox proportional hazards regression model was also used to examine the association of cochlear disorders with migraines. Results: Of the 1056 patients with migraines, 672 were women and 384 were men, and the mean (SD) age was 36.7 (15.3) years. Compared with the nonmigraine cohort, the crude hazard ratio for cochlear disorders in the migraine cohort was 2.83 (95% CI, 2.01-3.99), and the adjusted hazard ratio was 2.71 (95% CI, 1.86-3.93). The incidence rates of cochlear disorders were 81.4 (95% CI, 81.1-81.8) per 1 million person-years for the migraine cohort and 29.4 (95% CI, 29.2-29.7) per 1 million person-years for the nonmigraine cohort. The cumulative incidence of cochlear disorders in the migraine cohort (12.2%) was significantly higher than that in the matched nonmigraine cohort (5.5%). Subgroup analysis showed that, compared with the nonmigraine cohort, the adjusted hazard ratios in the migraine cohort were 3.30 (95% CI, 2.17-5.00) for tinnitus, 1.03 (95% CI, 0.17-6.41) for sensorineural hearing impairment, and 1.22 (95% CI, 0.53-2.83) for sudden deafness. Conclusions and Relevance: In this population-based study, the risk of cochlear disorders, especially for tinnitus, was found to be significantly higher among patients with a history of migraines. This finding may support the presence and/or concept of "cochlear migraine."

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.

[The results of bilateral cochlear implantation in the children who survived meningitis]. / Rezul'taty bilateral'noi kokhlearnoi implantatsii u detei, perenesshikh meningit.

The objective of the present study was the prospective analysis of the results of bilateral cochlear implantation (CI) in the children presenting with bilateral ossification of the cochlea after they had survived meningitis. A total of 15 patients underwent the surgical intervention. In those exhibiting bilateral ossification of the basal cochlear helix over the 5 mm segment (up to first bend of the cochlear turn) and partial ossification of the second helix (in 6 children), the affected portions were removed with the placement of two choleostomies, the lower one (from the ossified membrane of the cochlear window) and the upper one (toward the second helix). Activation of the speech processors of the CI systems was carried out within 4-6 weeks after surgery. The hearing abilities of the children were evaluated in accordance with the 'Estimation of the auditory perception categories', 'Estimation of the child's apprehension capacity', and 'Analysis of speech intelligibility rating' guidelines. In all the children with ossification over less than 5 mm of the basal cochlear helix, it proved possible to introduce the whole intracochlear electrode grid whereas only half of the electrode array was implanted in the cases of overall ossification of the basal helix. The first results obtained by telemetry and surdopedagogical testing gave evidence of the possibility of identifying various sources of non-verbal and speech stimuli in all the treated children at a small (up to 3 meters) distance.

Cochlear Dysfunction is not Common in Human Meningioma of the Internal Auditory Canal.

HYPOTHESIS: Cochlear dysfunction is not common in human meningioma of the internal auditory canal. BACKGROUND: Meningiomas arising from the cerebellopontine angle and internal auditory canal typically cause hearing loss. Cochlear dysfunction is known to contribute to sensorineural hearing loss induced by vestibular schwannoma, the most common tumor of the internal auditory canal. Detailed cochlear histopathology in meningioma has not been reported. METHODS: Retrospective analysis of cochlear histopathology in five unoperated and five operated meningiomas of the internal auditory canal identified after screening human temporal bone collections from three academic medical centers. RESULTS: While some dysfunction of all analyzed cochlear cell types was identified, a predominant or exclusive loss of hair cells was not observed in any meningioma. Only 14.3% of temporal bones showed significantly more hair cell damage on the side of the tumor when compared with the contralateral ear; cochlear neuronal damage was more prevalent in meningiomas. The incidence of hydrops, perilymphatic precipitate, or endolymphatic precipitate was low. CONCLUSIONS: Substantial cochlear damage in human meningioma of the internal auditory canal is not common. This may explain the anecdotal hearing improvement observed after surgical resection of meningioma. Our findings underline the importance of developing therapeutic strategies to prevent cochlear neuronal degeneration due to tumors of the internal auditory canal.

Delayed-onset haematoma formation after cochlear implantation.

OBJECTIVE: This paper presents our experience on delayed-onset haematoma formation after cochlear implantation, a topic which has not been well discussed in the literature. METHOD: Retrospective case review study. RESULTS: Five children who had undergone cochlear implant surgery at 1.5 to 4 years of age (median, 2.5 years) were studied. The haematoma episodes occurred 2-12 years (median, 6 years) after cochlear implantation. Two patients had recurrent episodes. Two of the seven haematoma episodes were managed by needle aspiration alone, four by incision and drainage alone, and one by both needle aspiration and incision and drainage. Other than one patient with coagulopathy, there were no obvious predisposing factors, including trauma. CONCLUSION: The majority of delayed-onset haematomas occurred without obvious predisposing factors. Needle aspiration can differentiate a haematoma from an abscess or cerebrospinal fluid leakage, and it provides an effective immediate therapeutic solution. However, aseptic techniques are emphasised to minimise the chances of an uncomplicated haematoma converting into a septic one.

Aberrant Internal Carotid Artery in the Tympanic Cavity.

OBJECTIVES: Presence of aberrant internal carotid artery (ICA) in the tympanic cavity is a very rare case and therefore the diagnosis is a challenge. Here, the authors aimed to address the importance of the diagnosis since the intervention to the middle ear and implants is increasing in number and this condition may lead to life-threatening bleeding. METHODS: Between 2012 and 2016, among the patients referred to the authors' Radiology Department from the Department of Otolaringology for the evaluation of the temporal region for various indications, the authors reported this anomaly in 6 patients and multidetector computerized tomography of these 6 patients and magnetic resonance imaging of 2 were assessed in detail. RESULTS: The mean age of the 6 patients was 28.8 and aberrant ICA abnormality was observed in 2 patients bilaterally and 4 patients unilaterally on the right side. In 1 patient ICA was not totally regressed and observed as hypoplastic. In one of the patients, dehiscence was evident between ICA and the cochlea. Moreover, in 1 patient the contralateral ICA was not observed. CONCLUSION: Although rare, aberrant ICA is an abnormality that should be kept in mind by the clinicians and the radiologists, since it leads to abundant bleeding when undiagnosed before the surgical interventions.

Perilymphatic fistula after underwater diving: a series of 11 cases.

INTRODUCTION: Onset of cochleovestibular symptoms (hearing loss, dizziness or instability, tinnitus) after a dive (scuba or breath-hold diving) warrants emergency transfer to an otology department. One priority is to investigate the possibility of the development of decompression sickness with a view to hyperbaric oxygen treatment of bubble-induced inner-ear damage. If this injury is ruled out, inner-ear barotrauma should be considered together with its underlying specific injury pattern, perilymphatic fistula. METHODS: We report on a series of 11 cases of perilymphatic fistula following ear barotrauma between 2003 and 2015, eight after scuba diving and three after free diving. All patients underwent a series of laboratory investigations and first-line medical treatment. RESULTS: Seven patients had a perilymphatic fistula in the left ear and four in the right. Eight cases underwent endaural surgical exploration. A fistula of the cochlear fenestra was visualised in seven cases with active perilymph leakage seen in six cases. After temporal fascia grafting, prompt resolution of dizziness occurred, with early, stable, subtotal recovery of hearing in seven. Of six patients in whom tinnitus occurred, this disappeared in two and improved in a further two. Two patients were not operated on because medical treatment had been successful, and one patient refused surgery despite the failure of medical treatment. Median follow-up time was 7.4 years (range 0.3 to 12). CONCLUSION: The diagnosis of perilymphatic fistula is based on clinical assessments and various laboratory findings. When there was strong evidence of this condition, surgery yielded excellent functional outcomes in all patients treated early.

Cochlear obliteration after translabyrinthine vestibular schwannoma surgery.

The objective of the study was to determine the temporal occurrence of cochlear obliteration following translabyrinthine vestibular schwannoma resection. A retrospective chart review, cross-sectional study, and sequential analysis of the time series were performed. The retrospective study included patients undergoing translabyrinthine resection for stage T1-T2 vestibular schwannoma from 2007 to 2010 without prior therapy and postoperative follow-up including MRI of the brain and the cerebellopontine angle. Already 3 months after surgery a radiographic labyrinthine change was observed in 66.7 %, a partial obstruction in 50 %, and an obstruction limited to the saccule in 16.7 %. Only 33.3 % of the patients showed an unchanged inner ear. In consideration of early cochlear obstruction after translabyrinthine vestibular schwannoma resection, temporary follow-up is necessary. Since the indications for cochlear implantation (CI) have been extended, especially concerning patients with single-side deafness, a simultaneous or early second-stage CI after tumour removal should be discussed.

The effect of radiofrequency radiation generated by a Global System for Mobile Communications source on cochlear development in a rat model.

OBJECTIVE: This study aimed to determine the effect of radiofrequency radiation generated by 900 and 1800 MHz Global System for Mobile Communications sources on cochlear development in the rat model. METHODS: Eight pregnant albino Wistar rats were divided into three groups: control, 900 MHz and 1800 MHz. The latter two groups of pregnant rats were exposed to radiofrequency radiation for 1 hour per day starting on the 12th day of pregnancy until delivery. The rats in the control, 900 MHz and 1800 MHz groups gave birth to 24, 31 and 26 newborn rats respectively. Newborn rats in the 900 MHz and 1800 MHz groups were exposed to radiofrequency radiation for 1 hour per day for 21 days after delivery. Hearing evaluations of newborn rats were carried out using distortion product otoacoustic emissions testing. Eight newborn rats were randomly selected from each group for electron microscopic evaluation. RESULTS: Distortion product otoacoustic emission tests revealed no significant difference among the groups, but electron microscopic evaluation revealed significant differences among the groups with regard to the number of normal, apoptotic and necrotic cells. CONCLUSION: The findings indicated cellular structural damage in the cochlea caused by radiofrequency radiation exposure during cochlear development in the rat model.