The pathophysiology of otosclerosis: Review of current research

Incidentally Discovered 99mTc-MDP Uptake on Bone Scan in Otosclerosis

Otosclerosis is a poorly understood clinical entity causing progressive conductive hearing loss. Here we present the first known evidence of otosclerosis demonstrating 99mTc-MDP uptake on bone scan. This presents an opportunity to explore the role of nuclear medicine imaging in early detection, staging, and even informing treatment and prognosis of this condition. Laryngoscope, 134:4763-4765, 2024.

Cochlear implantation in otosclerosis: surgical and audiological outcomes between ossified and non-ossified cochlea

AIM

To evaluate (1) Audiological and surgical outcomes in patients with otosclerosis following cochlear implantation. (2) surgical difficulties and outcomes between both groups. (3) Audiological outcomes between both groups.

STUDY DESIGN AND SETTING

Retrospective study conducted at Otology and Skull Base Surgery Center.

SUBJECTS AND METHODS

Data were analyzed from 111 patients with otosclerosis (114 ears) who underwent cochlear implant surgery using the cochlear implant database. Demographic characteristics (age, sex, and operated ear), auditory outcomes, and operative details (extent of cochlear ossification, surgical approach [posterior tympanotomy or subtotal petrosectomy], electrode insertion [partial/complete, scala tympani or vestibuli], and complications) were analyzed Auditory outcomes were assessed over at least one year follow-up period using pure tone audiometry and speech discrimination scores. Patients were divided into two groups (with and without cochlear ossification) to compare auditory outcomes and surgical outcomes.

RESULTS

The mean age of patients with ossified and non-ossified cochlea was 60.04 and 62.22 years respectively. Sixty-five of 114 ears had cochlear ossification, with complete round window involvement in 75.4% of these patients, while the rest had partial or complete basal turn ossification. Subtotal petrosectomy was performed in 63.1% and 28.6% of ossified and non-ossified cochlea respectively while the rest underwent cochlear implantation through posterior tympanotomy. Only one case had scala vestibuli insertion and four had incomplete electrode insertion. Six patients underwent re-implantation due to infection, device failure, and erosion of the posterior canal wall. Auditory outcomes among patients with ossified otosclerosis were slightly better than those without ossification but this difference was not statistically significant.

CONCLUSION

Cochlear implantation for otosclerosis yields excellent auditory outcomes with a low rate of surgical complications, despite the high incidence of cochlear ossification.

Effectiveness of bisphosphonate for alleviating tinnitus associated with otosclerosis: a prospective case-control study

PURPOSE

To investigate the short-term efficacy of third-generation bisphosphonate in the management of tinnitus associated with otosclerosis.

METHODS

A prospective case-control study included 100 patients with otosclerosis-associated bothersome tinnitus. Patients were assigned to two groups: group A (control): 25 patients who planned to receive only complementary supplements, oral vitamin D plus calcium, and group B (case): 75 patients who planned to receive oral bisphosphonate plus routine vitamin D and calcium supplements. Group B was subdivided into B1: 25 patients without any previous intervention, B2: 25 patients with persistent tinnitus for more than 6 months after a previous uncomplicated stapedotomy in the same ear, and B3: 25 patients with persistent tinnitus for more than 6 months after hearing aid fitting. The outcome was tinnitus assessment both subjectively (tinnitus intensity, frequency, and questionnaire) and objectively (tinnitus intensity and frequency).

RESULTS

The female-to-male ratio was 1.6:1 with ages ranging from 40 to 61 years. The baseline revealed no statistically significant differences between the groups. After 6 months, there were statistically significant differences, both objectively and subjectively. The tinnitus questionnaire median (IQR) for group B was 16 (30), whereas control group A had 52 (24). The tinnitus severity median (IQR) for group B was 20 (30), compared to group A's 52 (42). After 6 months, 40% of the cases in group B demonstrated complete improvement, compared to 0% in control group A.

CONCLUSION

We demonstrated significant tinnitus improvement in cases treated with bisphosphonate compared to the control group.

Stochastic modeling of the human middle ear dynamics under pathological conditions

BACKGROUND

Although the dynamics of the middle ear (ME) have been modeled since the mid-twentieth century, only recently stochastic approaches started to be applied. In this study, a stochastic model of the ME was utilized to predict the ME dynamics under both healthy and pathological conditions.

METHODS

The deterministic ME model is based on a lumped-parameter representation, while the stochastic model was developed using a probabilistic non-parametric approach that randomizes the deterministic model. Subsequently, the ME model was modified to represent the ME under pathological conditions. Furthermore, the simulated data was used to develop a classifier model of the ME condition based on a machine learning algorithm.

RESULTS

The ME model under healthy conditions exhibited good agreement with statistical experimental results. The ranges of probabilities from models under pathological conditions were qualitatively compared to individual experimental data, revealing similarities. Moreover, the classifier model presented promising results.

DISCUSSION

The results aimed to elucidate how the ME dynamics, under different conditions, can overlap across various frequency ranges. Despite the promising results, improvements in the stochastic and classifier models are necessary. Nevertheless, this study serves as a starting point that can yield valuable tools for researchers and clinicians.

Surgical decision-making in superior canal dehiscence syndrome with concomitant otosclerosis

OBJECTIVE

The diagnosis and management of Superior Canal Dehiscence Syndrome (SCDS) with concomitant otosclerosis can be a challenge. Otosclerosis can mask SCDS symptoms and stapes surgery may reveal or exacerbate vestibular symptoms. Our aim is to present four cases of SCDS with concomitant otosclerosis and thereby informing the reader about the possibility of this dual occurrence and its implications for treatment.

CASES

Four patients with SCDS and concomitant otosclerosis are presented. Two patients underwent surgical treatment for both SCDS and otosclerosis and two patients opted for conservative management.

OUTCOMES

The main differences between surgically and non-surgically treated cases are the presence of autophony and pressure-induced vertigo and a more severe experience of symptoms in surgically treated cases. Surgically treated cases achieved a sizeable reduction in postoperative air-bone gap and resolution of vestibular symptoms.

CONCLUSION

The subjective severity of symptoms in combination with shared decision-making is key in determining the appropriate treatment plan for SCDS and concomitant otosclerosis.

Endoscopic Versus Microscopic Stapedotomy: A Randomized Clinical Trial

OBJECTIVE

To determine the outcomes and complications of endoscopic versus microscopic stapes surgery in patients with otosclerosis.

STUDY DESIGN

Randomized, single-blinded clinical trial.

METHODS

Patients with otosclerosis who underwent either trans-canal microscopic or endoscopic stapedotomy at a tertiary care hospital were compared. Thirty-two patients were randomly divided into two groups using blocked randomization. Group A consisted of 16 patients who underwent trans-canal microscopic stapedotomy, and group B consisted of 16 patients who underwent trans-canal endoscopic stapedotomy. Postoperative vertigo, ear pain, and complications such as tympanic membrane perforation or chorda tympani nerve injury were evaluated. Three months postoperatively, patients were assessed for dysgeusia and hearing improvement.

RESULTS

The mean pre-operative air-bone gap (ABG) in the microscopic and endoscopic groups was 32.81 ± 6.82 and 30.00 ± 7.96, respectively. The mean improvement in the ABG was 25.45 ± 11.21 dB in the microscopic group and 23.21 ± 10.68 dB in the endoscopic group. Although both techniques showed improvement in auditory outcomes (p-value <0.001), there were no statistical differences between the endoscopic and microscopic groups in the pre-operative, post-operative, and mean improvement of ABG (p-value >0.05). There were no significant differences between the two methods in chorda tympanic nerve injury, vertigo scores, and the mean operating time (p-value >0.05), but the mean pain score was higher in the microscopic group (2.56 ± 1.55 in the microscopic group versus 1.31 ± 0.70 in the endoscopic group) (p-value = 0.003).

CONCLUSIONS

Endoscopic stapes surgery can be a preferable alternative to conventional microscopic stapedotomy, as it yields similar hearing outcomes and lower pain scores.

LEVEL OF EVIDENCE

2 Laryngoscope, 134:2395-2400, 2024.

Are there relationship otosclerosis with serum HE4 and CA125 level? A pilot study

BACKGROUND

HE4 and CA 125 are identified as a potential biomarker for the detection of some diseases with fibrosis.

OBJECTIVES

The purpose of this pilot study was to evaluate the value of human epididymis protein 4 (HE4) and cancer antigen-125 (CA-125) in otosclerosis patients.

MATERIAL AND METHODS

The study population consisted of 60 people (30 otosclerosis patients, 30 control group). We collected blood samples for HE4 and CA-125 levels. Serum HE4 and CA-125 levels were measured by enzyme-linked immunosorbent assay (ELISA). We compared the results between otosclerosis patients and the normal subject. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was performed to evaluate the diagnostic value.

RESULTS

There was no differences in CA-125 level between the otosclerosis (20.3 U/mL [10.4-42.1] and control group (19.3 U/mL [15.3-49.8]) (p > 0.05). HE4 level was significantly higher in the otosclerosis group (60.9 pmol/L [32.1-101.8])] than the control group (25.3 pmol/L [12.4-91.9]) (p < 0.001). The AUC in ROC analysis of HE4 was 0.768 (p < 0.001).

CONCLUSIONS AND SIGNIFICANCE

Serum HE4 level may be a useful biomarker in otosclerosis. Further studies with a larger number of patients are required to confirm our pilot results.

SMARCA4 mutation causes human otosclerosis and a similar phenotype in mice

BACKGROUND

Otosclerosis is a common cause of adult-onset progressive hearing loss, affecting 0.3%-0.4% of the population. It results from dysregulation of bone homeostasis in the otic capsule, most commonly leading to fixation of the stapes bone, impairing sound conduction through the middle ear. Otosclerosis has a well-known genetic predisposition including familial cases with apparent autosomal dominant mode of inheritance. While linkage analysis and genome-wide association studies suggested an association with several genomic loci and with genes encoding structural proteins involved in bone formation or metabolism, the molecular genetic pathophysiology of human otosclerosis is yet mostly unknown.

METHODS

Whole-exome sequencing, linkage analysis, generation of CRISPR mutant mice, hearing tests and micro-CT.

RESULTS

Through genetic studies of kindred with seven individuals affected by apparent autosomal dominant otosclerosis, we identified a disease-causing variant in SMARCA4, encoding a key component of the PBAF chromatin remodelling complex. We generated CRISPR-Cas9 transgenic mice carrying the human mutation in the mouse SMARCA4 orthologue. Mutant Smarca4+/E1548K mice exhibited marked hearing impairment demonstrated through acoustic startle response and auditory brainstem response tests. Isolated ossicles of the auditory bullae of mutant mice exhibited a highly irregular structure of the incus bone, and their in situ micro-CT studies demonstrated the anomalous structure of the incus bone, causing disruption in the ossicular chain.

CONCLUSION

We demonstrate that otosclerosis can be caused by a variant in SMARCA4, with a similar phenotype of hearing impairment and abnormal bone formation in the auditory bullae in transgenic mice carrying the human mutation in the mouse SMARCA4 orthologue.

Brazilian Society of Otology task force - Otosclerosis: evaluation and treatment

OBJECTIVES

To review and provide evidence-based recommendations for the diagnosis and treatment of otosclerosis.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on otosclerosis were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: 1) Diagnosis - audiologic and radiologic; 2) Treatment - hearing AIDS, pharmacological therapy, stapes surgery, and implantable devices - bone-anchored devices, active middle ear implants, and Cochlear Implants (CI).

CONCLUSIONS

The pathophysiology of otosclerosis has not yet been fully elucidated, but environmental factors and unidentified genes are likely to play a significant role in it. Women with otosclerosis are not at increased risk of worsening clinical condition due to the use of contraceptives or during pregnancy. Drug treatment has shown little benefit. If the patient does not want to undergo stapedotomy, the use of hearing aids is well indicated. Implantable systems should be indicated only in rare cases, and the CI should be indicated in cases of profound deafness.

Vertigo Associated with Otosclerosis and Stapes Surgery-A Narrative Review

Otosclerosis is a pathological condition affecting the temporal bone, and is characterized by remodelling of the labyrinthine bone tissue through a dynamic process of osteolysis and osteogenesis. This condition progressively leads to hearing loss, tinnitus, and vertigo. Stapedotomy, a surgical procedure involving the removal of the stapes superstructure and its replacement with a prosthesis, is the treatment of choice to improve hearing in individuals with otosclerosis. However, vestibular dysfunction is a significant complication associated with this procedure, which can occur intraoperatively or postoperatively, ranging from the immediate postoperative period to weeks, months, or even years after surgery. This paper aims to provide a comprehensive review of the most important causes of vertigo associated with otosclerosis and stapes surgery with the goal of minimizing the incidence of this complication. Understanding the underlying factors contributing to vertigo in this context is crucial for the prevention and effective management of vertigo in patients undergoing stapedotomy.

Juvenile otosclerosis and congenital stapes footplate fixation. A systematic review and meta-analysis of surgical outcomes and management

OBJECTIVE

Juvenile Otosclerosis (JO) and Congenital Stapes Footplate Fixation (CSFF) are rare ossicular chain disorders seen in the paediatric population and present with conductive hearing loss. Ongoing controversy exists regarding the role of surgical intervention in JO and CSFF given the poorer hearing outcomes and complications when compared with surgical intervention for adult otosclerosis. The objective of this study is to assess the published data on the surgical outcomes of JO and CSFF in order to guide clinicians and counsel patients on the various medical options for these disease entities.

METHODS

A systematic review of MEDLINE, EMBASE and Cochrane was performed with inclusion criteria of children with JO or CSFF and hearing outcomes following stapes surgery. Studies identified by the search were reviewed and assessed by two independent reviewers in line with the PRISMA guidelines.

RESULTS

464 articles were initially reviewed and 28 articles met inclusion in the systematic review and meta-analysis. A total of 810 ears (473 and 337 cases of JO and CSFF respectively) underwent stapes surgery. Average age at time of surgery for JO and CSFF was 14.3 and 10.2 years old respectively. The mean pre-operative Air-Bone-Gap (ABG) for JO and CSFF was 31.8 ± 5.2 dB and 39.4 ± 10 dB respectively. Following stapes surgery, the mean post-operative ABG for JO and CSFF was 9.6 ± 6 dB and 19.2 ± 12.5 dB respectively. Surgical success rate (defined as ABG <10 dB) was 81% for JO and 41% for CSFF. Mean ABG gain for JO and CSFF was 24.8 dB (95% CI: 18.6-33.1) and 22.6 dB (95% CI: 18.4-27.8) respectively. The reported number of dead ears was 4/473 (0.8%) for JO and 2/337 (0.6%) for CSFF. 23 cases (2.8%) reported sensorineural hearing loss (SNHL) >10 dB.

CONCLUSION

CSFF was associated with poorer hearing outcomes compared to JO, however both entities showed similar improvement in ABG post operatively. Counselling patients and their families on the surgical success rates and complications of JO or CSFF is an important part of the decision making process when deciding between a surgical option or conservative measures such as hearing aids.

Genome-wide screen of otosclerosis in population biobanks: 27 loci and shared associations with skeletal structure

Otosclerosis is one of the most common causes of conductive hearing loss, affecting 0.3% of the population. It typically presents in adulthood and half of the patients have a positive family history. The pathophysiology of otosclerosis is poorly understood. A previous genome-wide association study (GWAS) identified a single association locus in an intronic region of RELN. Here, we report a meta-analysis of GWAS studies of otosclerosis in three population-based biobanks comprising 3504 cases and 861,198 controls. We identify 23 novel risk loci (p < 5 × 10-8) and report an association in RELN and three previously reported candidate gene or linkage regions (TGFB1, MEPE, and OTSC7). We demonstrate developmental stage-dependent immunostaining patterns of MEPE and RUNX2 in mouse otic capsules. In most association loci, the nearest protein-coding genes are implicated in bone remodelling, mineralization or severe skeletal disorders. We highlight multiple genes involved in transforming growth factor beta signalling for follow-up studies.

Do CT values change over time and correlate with hearing in the non-surgical ears of otosclerosis patients?

BACKGROUND

High-resolution computed tomography (HRCT) is often used to diagnose otosclerosis.

AIMS/OBJECTIVES

To investigate whether CT values change over time and correlate with hearing in the non-surgical ears of otosclerosis patients.

MATERIALS AND METHODS

32 patients with bilateral otosclerosis who had undergone unilateral stapedectomy were enrolled in the study. HRCT examination and pure tone audiometry were performed before and after the surgery. CT values of different regions of interest (ROIs) were measured manually and the data were collected for analysis.

RESULTS

The CT value of anterior to the inner auditory meatus (AIAM) decreased by 88.5 HU (p < .05), and the changes in CT values in other ROIs showed no statistical difference. Regarding hearing, the value of air bone gap (ABG) increased by 3.6 dB (p = .020), and the average hearing deterioration rate of ABG was 3.1 dB/year. The CT value of the mid-point of the stapes footplate (MPSF) showed a certain correlation with the change of ABG (p < .05).

CONCLUSIONS AND SIGNIFICANCE

The CT value of AIAM may change over time. The overall hearing of non-surgical ears in otosclerosis patients shows a deteriorating trend. Moreover, the changes in the CT value of MPSF may be related to the hearing, which needs further research.

Role of HRCT Temporal Bone in Predicting Surgical Difficulties Encountered in Fenestral Otosclerosis Surgery

To study spectrum of high resolution computed tomography (HRCT) imaging findings in otosclerosis, to predict approximate length of prosthesis required from pre-operative HRCT measurements and to correlate between oval window niche (OWN) height preoperatively and difficulty in introducing foot plate perforator during surgery. A cross sectional study was conducted on 23 patients with a clinical diagnosis of otosclerosis from September 2018 to July 2020. Sensitivity of HRCT in detecting otosclerosis, correlation between pre-operative incudo-stapedial length (ISL) and intra operative prosthesis length, and correlation between OWN height and difficulty in introducing perforator were sought. The mean age of 23 patients studied was 39.9 years with a female preponderance of 56.5%. 17 out of 19 patients with foci of otosclerosis during surgery had HRCT findings of otosclerosis providing a sensitivity of 89.5%. Mean OWN height obtained was 1.29 mm preoperatively and a cut off value of 1.325 mm found using receiver operating characteristic curve method classifying OWN height as narrow or normal. Mean ISL measured pre operatively was 4.25 mm and mean length of prosthesis used was 4.56 mm with significant positive correlation using intraclass correlation coefficient method with correlation coefficient = 0.879. HRCT is an invaluable modality aiding the surgeon to detect otosclerotic foci with high sensitivity, identify thick obliterative otosclerotic foci requiring additional drilling, to predict the length of prosthesis used and to predict difficulties in approaching footplate when OWN height is below 1.325 mm.

Tinnitus and Otosclerosis: An Exploratory Study about the Prevalence, Features and Impact in Daily Life

Introduction  Tinnitus is experienced by a significant part of the patients suffering from otosclerosis. Objective  To assess the prevalence of tinnitus in otosclerosis, its main features, and the impact on the daily life. Methods  Patients diagnosed with otosclerosis in 2019 in a tertiary hospital were enrolled in the study. Demographic data were retrieved and, besides a regular audiometric evaluation, the patients underwent acuphenometry to assess the psychoacoustic measurements (pitch and loudness), and the Tinnitus Handicap Inventory (THI). Results  In total, 66 patients fulfilled the inclusion criteria, with a female predominance (63.6%; n = 42), and a mean age of 48.7 years. The mean air-bone gap was of 26.3 dB. A total of 72.7% complained of tinnitus; it was mostly unilateral, identified in the low frequencies, namely 500 Hz, with median loudness of 7.5 dB. The median score on the THI score was of 37; most patients had a mild handicap (33.3%, n = 16), followed by those with a severe handicap (22.9%; n = 11). The female gender had a statistically significant association with the presence of tinnitus. The THI scores were higher in middle-aged patients (age groups: 40 to 49 and 50 to 59 years), which was statistically significant. No correlation was found between audiometry results and the prevalence of tinnitus or score on the THI. On the other hand, high-pitched tinnitus, compared to low pitched-tinnitus, was associated with larger air-bone gaps. Conclusion  The prevalence of tinnitus in our population was in line with the prevalences reported in the literature. It caused a catastrophic handicap in 22.9% of the patients. High-pitched tinnitus was associated with higher handicap. Nonetheless, the existence of tinnitus and its severity were not associated with the degree of hearing loss.

A Systematic Review of the Effectiveness of Bisphosphonates for Otosclerosis

OBJECTIVE

To systematically review the evidence for the use of bisphosphonate therapy in otosclerosis through clinically relevant outcomes.

DATABASES REVIEWED

MEDLINE, EMBASE, PubMed, and CINAHL databases were searched up to July 12, 2021.

METHODS

RCTs and cohort studies investigating the effect of bisphosphate therapy on adults or children diagnosed with otosclerosis were included. The risk of bias within trials was examined using the ROB2 tool for RCTs, and the ROBINS-I for non-RCTs.

RESULTS

Three studies reported over five publications were included in the systematic review. Data from one RCT at 6 months did not demonstrate any improvement nor deterioration in audiological outcomes in participants treated with Sodium Alendronate. Data from MRI in this group demonstrated improvements in the SI of the otosclerotic foci at the RAOW compared to participants taking placebo. In another RCT, improvements in audiological outcomes were seen at 12 and 24 months in individuals treated with Etidronate Sodium. Long-term data from a retrospective cohort study demonstrated stabilisation of hearing in individuals with otosclerosis and progressive SNHL.

CONCLUSION

There is insufficient evidence to recommend the routine use of bisphosphonates in otosclerosis patients at present. Long-term retrospective data has suggested a role for bisphosphonates in the subset of patients with deteriorating sensorineural hearing loss with the aim of hearing stabilisation. Adequately powered RCTs with long term follow up will be required to evaluate this further.

Update from the 5th Edition of the World Health Organization Classification of Head and Neck Tumours: Tumours of the Ear

In the recently published 5th Edition of the World Health Organisation Classification of Head and Neck Tumours, there are relatively few changes to report in terms of nomenclature in lesions of ear and temporal bone and fewer developments in molecular pathogenesis in comparison to other sites, particularly in sinonasal tract. Ear and temporal bone tumours are rare and biopsy material is limited. As a result, resources in the literature are scarce with few large series, no controlled clinical trials and the approaches to staging and management are not standardised. New entities are difficult to characterise. The number of entries has, however, increased for tumours of the ear and temporal bone (thirteen) compared to the 4th Edition (eleven). Some lesions previously included in the 4th Edition considered to have no site-specific features have been excluded to be discussed elsewhere and other benign lesions that are specific to this site have been included. The tumours and tumour-like entities of ear and temporal bone are discussed here mindful that the chapter in the 5th edition better correlates disease processes with clinical information and imaging and as far as possible standardises nomenclature.

Cochlear Implantation in Advanced Otosclerosis: Pitfalls and Successes

Purpose of Review

This review will highlight recent outcome-based evidence guiding decision making for cochlear implantation in advanced otosclerosis, related complications, and technical surgical considerations in otosclerosis and the obstructed cochlea.

Recent Findings

Cochlear implantation in advanced otosclerosis results in consistent, excellent auditory outcomes with improvement in both objective speech recognition scores and subjective quality of life measures. Facial nerve stimulation may occur at higher rates in otosclerosis cochlear implant recipients. Cochlear implantation in the setting of luminal obstruction in osteosclerotic patients may be managed with altered surgical technique to achieve successful auditory improvements. Pre-operative imaging with high resolution CT or MRI may help anticipate intraoperative challenges and post-operative complications in cochlear implantation.

Summary

Cochlear implantation is an established, successful treatment for profound hearing loss in advanced otosclerosis. Surgeon knowledge of outcomes, complications, and potential surgical challenges is important to appropriately counsel patients regarding auditory rehabilitation options in advanced otosclerosis.

Two-handed endoscopic ear surgery: Feasibility for stapes surgery

OBJECTIVE

Endoscopic ear surgery is becoming an increasingly popular approach. Our aim in this study is to evaluate the feasibility of the two-handed endoscopic technique for stapes surgery, which has its own unique steps.

METHODS

Patients who underwent two-handed endoscopic stapes surgery between September 2017 and February 2018 were included in this study. Preoperative and postoperative pure tone averages and air bone gaps, intraoperative complications were recorded. All procedures were performed under hypotensive general anesthesia by the same surgeon using 0° rigid endoscopes of 2.7-mm diameter, 14-cm length with an endoscope holder.

RESULTS

Seven endoscopic two-handed stapes surgery were performed between September 2017 and February 2018. Of these, six patients were operated entirely endoscopically because one patient was found to has perilymph gusher and converted to microscopic surgery. There were no intraoperative tympanic membrane injuries, facial nerve paresis or sensorineural hearing losses. The average preoperative ABG of patients who underwent fully endoscopic surgery was 31.3 dB, and the postoperative ABG closed up to 9.6 dB.

CONCLUSIONS

Adoption of the two-handed technique during endoscopic stapes surgery ensures the surgeon benefits from the advantages of endoscopy while overcoming the disadvantages of the one-handed technique.

Stability of computed tomography densitometry in patients with otosclerosis:a two-year follow-up

Objectives

To quantify the progression of otosclerosis in the unoperated ear between two stapedotomy procedures for patients with bilateral otosclerosis which can help to determine whether a HRCT scan should be re-performed before the second surgery for patients who already received HRCT imaging before the initial surgery.

Methods

35 patients who underwent bilateral stapedotomy were included. Two rounds of HRCT examination and audiometry were performed at the time of the first surgery and second surgery on the ear that was not operated on during the initial surgery. The relationship between the changes in HRCT densitometry and audiometry over time was analyzed.

Results

The second round of HRCT did not add significant information about the changes to the otosclerosis lesions in either the imaging diagnosis or the HRCT density values except for small changes in the HRCT densitometry readings at the area anterior to the inner auditory (P = 0.01). While the changes in HRCT manifestation are small, changes near the fissula ante fenestram (FAF) were still positively correlated with the air bone gap (ABG) of patients (p = 0.031, r = 0.388).

Conclusions

The progression of lesions in otosclerosis is slow resulting in small and insignificant changes to the HRCT features. Therefore, a repeat HRCT evaluations prior to surgery is not necessary for patients who have had a previous HRCT evaluation within 2 years of the operation. The small changes in HRCT manifestation near the FAF were still correlated with negative effects on the ABG which could cause worsened hearing thresholds over this timeframe.

The Stapes in Otosclerosis: Osteoarthritis of an Ear Ossicle

Otosclerosis is a pagetoid proliferation of bone remodeling, vascular proliferation, bone resorption and new bone formation in the tympanic region of the temporal bone. The resulting anklyosis of the stapes footplate as it articulates with the oval window is the most common cause of conductive hearing loss in young to middle aged, predominantly Caucasian individuals. The characteristic histologic features have been well documented by autopsy studies of the temporal bone. Although stapedectomy is the surgical treatment for otosclerosis, the stapes specimen may be submitted for gross examination only or not examined at all. A retrospective study of 73 stapedectomy specimens (2008-2019) not including the stapes footplate. Clinical features from the electronic medical record as well as standard histologic sections from surgical specimens were reviewed. Neither the stapedal head nor crura showed histologic features of otosclerosis. There was mild osteoarthritis affecting the head, possibly as a consequence of persistent ossicular vibration superimposed on the ankylosed rigidity. The most common changes were surface fissuring (65%), cartilaginous erosion (49%) and irregularity of the osteochondral interface (51%). An occasional osteophyte (8%) was observed. The ear ossicles, embryologically analogous to long bones of the extremities, develop via endochondral ossification and exhibit articular surfaces of hyaline cartilage. The present observations suggest that a consequence of otosclerotic ankylosis is osteoarthritis of the stapedal head. In this study, the histological features could not be correlated with the severity of hearing loss or duration of clinical disease.

Cochlear implantation among patients with otosclerosis: a systematic review of clinical characteristics and outcomes

PURPOSE

There have been considerable advancements in cochlear implants in different clinical scenarios; however, their use in patients with otosclerosis remains challenging. This review aimed to investigate the surgical and clinical outcomes of cochlear implantation in patients with otosclerosis.

METHODS

An electronic literature search was performed using four main databases through February 2021 to identify original studies of cochlear implantation in patients with otosclerosis for inclusion in this systematic review. The study protocol was registered with the Prospectively Registered Systematic Reviews and Meta-analyses (reference number: CRD42021234753).

RESULTS

A total of 23 studies including 3162 patients were enrolled. Of these patients, only 392 had otosclerosis and underwent cochlear implantation. The duration of deafness was reported in only eight studies, extending up to 50 years. Far-advanced otosclerosis was observed in 153 patients. A total of 56 patients used hearing aids. Stapedectomy and stapedotomy were performed in 118 and 63 patients, respectively. In three studies, the temporary success of stapedectomy and stapedotomy was 6 (43%) and 5 (71%) patients, respectively. Computed tomography was used as a preoperative assessment tool in most studies (n = 14, 60.9%). Incomplete implant insertion occurred in 17 patients, while facial nerve stimulation occurred in 36 patients after implantation.

CONCLUSION

Cochlear implantation is a relatively safe modality that can provide promising audiological outcomes in patients with otosclerosis. However, several factors, including cochlear ossification, duration of deafness, and previous operations, can affect its outcomes. Further studies with a larger sample population are recommended.

Does stapedotomy improve high frequency conductive hearing?

OBJECTIVES

Stapedotomy is performed to address conductive hearing deficits. While hearing thresholds reliably improve at low frequencies (LF), conductive outcomes at high frequencies (HF) are less reliable and have not been well described. Herein, we evaluate post-operative HF air-bone gap (ABG) changes and measure HF air conduction (AC) thresholds changes as a function of frequency.

METHODS

Retrospective review of patients who underwent primary stapedotomy with incus wire piston prosthesis between January 2016 and May 2020. Pre- and postoperative audiograms were evaluated. LF ABG was calculated as the mean ABG of thresholds at 250, 500, and 1000 Hz. HF ABG was calculated at 4 kHz.

RESULTS

Forty-six cases met criteria. Mean age at surgery was 54.0 ± 11.7 years. The LF mean preoperative ABG was 36.9 ± 11.0 dB and postoperatively this significantly reduced to 9.35 ± 6.76 dB, (P < .001). The HF mean preoperative ABG was 31.1 ± 14.4 dB and postoperatively, this also significantly reduced to 14.5 ± 12.3 dB, (P < .001). The magnitude of LF ABG closure was over 1.5 times the magnitude of HF ABG closure (P < .001). The gain in AC decreased with increasing frequency (P < .001).

CONCLUSION

Hearing improvement following stapedotomy is greater at low than high frequencies. Postoperative air bone gaps persist at 4 kHz. Further biomechanical and histopathologic work is necessary to localize postoperative high frequency conductive hearing deficits and improve stapedotomy hearing outcomes.

LEVEL OF EVIDENCE

4, retrospective study.

Classification of Wideband Tympanometry by Deep Transfer Learning with Data Augmentation for Automatic Diagnosis of Otosclerosis

Otosclerosis is a common disease of the middle ear leading to stapedial fixation. Its rapid and non-invasive diagnosis could be achieved through wideband tympanometry (WBT), but the interpretation of the raw data provided by this tool is complex and time-consuming. Convolutional neural networks (CNN) could potentially be applied to this situation to help the clinicians categorize WBT data. A dataset containing 135 samples from 80 patients with otosclerosis and 55 controls was obtained. We designed a lightweight CNN to categorize samples into the otosclerosis and control. Receiver operating characteristic (ROC) analysis showed an area under the curve (AUC) of 0.95 0.011, and the F1-score was 0.89 0.031 (r=10). The performance was further improved by data augmentation schemes and transfer learning strategies (AUC: 0.97 0.010, F1-score: 0.94 0.016, p<0.05, ANOVA). Finally, the most relevant diagnostic features employed by the CNN were assessed via the activation pattern heatmaps. These results are crucial for the visual interpretation of WBT graphic outputs which clinicians use in routine, and for a better understanding of the WBT signal in relation to the ossicular mechanics.

Endoscopic Stapedectomy: Collective Experience From a Large Australian Center

INTRODUCTION

Endoscopic stapes surgery is a technically demanding procedure that is increasing in popularity. Surgical outcomes and complication rates have been demonstrated to be comparable to traditional microscopic techniques. The surgical outcomes for patients undergoing stapes surgery performed by the Sydney Endoscopic Ear Surgery Research Group are presented.

STUDY DESIGN

Retrospective review from prospectively gathered database.

SETTING

Tertiary referral centers.

PATIENTS

A retrospective case review of patients undergoing endoscopic stapes surgery performed by four surgeons between February 2015 and July 2019 was carried out. Sixty nine patients were identified, and assessed for demographics, functional results, and postoperative complications.

INTERVENTION

Endoscopic stapedotomy.

MAIN OUTCOME MEASURE

Postoperative hearing results.

RESULTS

Sixty eight of 69 patients (98.6%) achieved an air-bone gap (ABG) closure of less than 20 dB. Sixty of 69 patients (87%) achieved and ABG closure of less than 10 dB. The average improvement of the ABG over four frequencies achieved was 26.5 dB (range, 0-61). Postoperative complications were infrequent and self-limiting. Six patients experienced dysgeusia without obvious chorda tympani injury, four patients developed short lived vertigo, and two patients experienced tinnitus.

CONCLUSIONS

Endoscopically assisted stapes surgery represents a safe alternative to traditional microscopic techniques, with similar morbidity and audiological outcomes.

Beethoven's death-the result of medical malpractice?

Two different strands of hair taken from Beethoven’s head after his death were examined for heavy metals using scanning electron microscopy (SEM) and laser ablation-ICP-MS (inductively coupled plasma–mass spectroscopy). The results revealed the presence of small lead particles on the surface of Beethoven’s hairs and fluctuating lead levels in hair medulla along the length of the hair due to alternating lead exposure, with an average lead exposure of 100 times the normal value. The time-line attached to the peaks of these fluctuating values correlate with the pneumonia treatment and the paracenteses performed, including the subsequent treatment of the procedure wounds. While the administration of lead-containing drugs and treatments had been proven to resolve the pneumonia, it had simultaneously caused massive liver failure, accelerated by pre-existing cirrhosis. The question as to whether Beethoven’s death was a case of malpractice can only be answered from a forensic point of view ex ante, since the state of the medical knowledge of the time has to be taken into account.

[Hormonal influence on hearing]

BACKGROUND

Hearing loss leads to impairments in communication, social interactions, and cognitive functions. This renders early treatment particularly important. A causal therapy is not yet available. Human and animal studies have shown that certain hormones can have a positive effect on hearing.

OBJECTIVE

This review provides an overview of the effects of various hormones on hearing and describes the potential benefit for future therapeutic approaches.

MATERIALS AND METHODS

A systematic literature review of reviews dealing with the effects of various hormones on hearing in humans and animals published in PubMed between 2015 and 2020 was conducted.

RESULTS

Hormones may mediate antiapoptotic effects on structure-relevant cells of the cochlea and auditory pathway, and may influence hair cell functionality or the electrolyte balance of the endo- and perilymph. Current research focuses on glucocorticoids; the mineral corticoid aldosterone; the sex hormones estrogen, progesterone, and testosterone; the growth hormones GH (growth hormone) and IGF‑1 (insulin-like growth factor 1); thyroid hormones; and insulin. Study results are still inconsistent at this time, but various hormones appear to represent a possible future treatment option for acute hearing loss. Long-term hormone treatment, which would be necessary particularly in the case of age-related hearing loss, does not currently represent a sensible course of action due to the side effect profile of the systemic treatment/lack of practicable topical application options.

CONCLUSION

The mode of action of hormones is complex. Whether they can be used in the future for individualized treatment of patients with acute hearing impairment requires further investigation.

The Prevalence of Internal Auditory Canal Diverticula Is Constant Over a Large Age Range Among Patients Not Imaged for Hearing Loss

OBJECTIVE

The objective of this study is to establish the prevalence of internal auditory canal diverticula spanning all age groups imaged for reasons other than hearing loss and to investigate changes in prevalence with age to determine if it is a finding that develops over time.

METHODS

We retrospectively evaluated 1000 cervical spine computed tomographies obtained in patients age 0-99 years for presence of internal auditory canal diverticula.

RESULTS

A total of 405 patients (208 men; 197 women) were included. Internal auditory canal diverticula were identified in 23 patients (5.7%). No statistically significant association between internal auditory canal diverticula and patient age was found (P = 0.68).

CONCLUSIONS

The prevalence of internal auditory canal diverticula on cervical spine computed tomographies is 5.7%. No change in prevalence was observed with increasing age supporting the hypothesis that internal auditory canal diverticula represent a normal anatomic variant rather than acquired pathology.

Otosclerosis in an Urban Population

OBJECTIVE

To investigate the evolving prevalence of otosclerosis in a large urban population.

METHODS

A retrospective review of patients in a large, urban, public health system was conducted from January 2010 to August 2019 to identify subjects with otosclerosis. Diagnostic testing included audiometry and computed tomography scans. Sex, age at diagnosis, treatment received, race, ethnicity, and country of birth were analyzed for each subject and compared with all eligible patients in the reference population.

RESULTS

A total of 134 patients from a reference population of 672,839 were diagnosed with otosclerosis and analyzed. The otosclerosis patients were predominantly Hispanic (73%), of which the majority were foreign born (87%). The average age at onset was 46 years and 59% were women. The overall prevalence of otosclerosis was 20 of 100,000 patients. The crude prevalence of otosclerosis by ethnicity was 43 of 100,000 for Hispanics, 12.6 of 100,000 for Caucasians, and 3 of 100,000 for African Americans. Within the Hispanic population, the prevalence of otosclerosis was 60 of 100,000 for foreign-born individuals and 16 of 100,000 for those born in the USA (odds ratio [OR] = 3.69, [95% confidence interval [CI], 2.02-6.76], p < 0.0001). Prevalence was not significantly different among Caucasians and US-born Hispanics.

CONCLUSION

Otosclerosis in the studied population was most common among Hispanic patients, though it was strongly influenced by country of birth. The "imported" otosclerosis cases are best explained by environmental influence rather than ethnic susceptibility. This discrepancy is likely due to variance in measles immunization rates among North and Central American countries before 1990.

Uncovering the secreted signals and transcription factors regulating the development of mammalian middle ear ossicles

The mammalian middle ear comprises a chain of ossicles, the malleus, incus, and stapes that act as an impedance matching device during the transmission of sound from the tympanic membrane to the inner ear. These ossicles are derived from cranial neural crest cells that undergo endochondral ossification and subsequently differentiate into their final functional forms. Defects that occur during middle ear development can result in conductive hearing loss. In this review, we summarize studies describing the crucial roles played by signaling molecules such as sonic hedgehog, bone morphogenetic proteins, fibroblast growth factors, notch ligands, and chemokines during the differentiation of neural crest into the middle ear ossicles. In addition to these cell-extrinsic signals, we also discuss studies on the function of transcription factor genes such as Foxi3, Tbx1, Bapx1, Pou3f4, and Gsc in regulating the development and morphology of the middle ear ossicles.

The Rise and Fall of Otosclerosis: A Population-based Study of Disease Incidence Spanning 70 Years

OBJECTIVE

Although it is commonly held that otosclerosis has become increasingly uncommon over recent decades, no population-based data exist to characterize this trend. Moreover, because most large epidemiologic databases within the United States primarily include cancer data, even the modern incidence of otosclerosis is unknown. The chief objective of the current work was to characterize the trend in the incidence of otosclerosis over 70 years using the unique resources of the Rochester Epidemiology Project.

STUDY DESIGN

Population-based study.

PATIENTS

Residents of Olmsted County, Minnesota diagnosed with otosclerosis.

MAIN OUTCOME MEASURE

Disease incidence from 1950 to 2017.

RESULTS

From 1950 to 2017, 614 incident cases of otosclerosis were identified. The incidence rose from 8.9 per 100,000 person-years in the 1950s to a peak of 18.5 from 1970 to 1974. From this peak, the incidence significantly declined to 6.2 per 100,000 person-years by the early-1990s and reached a nadir of 3.2 from 2015 to 2017 (p<0.001). From 1970 to 2017, age at diagnosis (p = 0.23) and the proportion of bilateral cases (p = 0.16) did not significantly change; pure-tone average at diagnosis did not clinically appreciably change over the study period (median difference <5 dB across decades, p = 0.034).

CONCLUSIONS

The incidence of otosclerosis drastically declined since the early-1970s. Historically considered one of the most common causes of acquired hearing loss, the low modern incidence of otosclerosis renders it legally a "rare disease" within the United States. These trends require consideration when determining trainee case requirements and developing practice guidelines.

Rising Incidence of Sporadic Vestibular Schwannoma: True Biological Shift Versus Simply Greater Detection

OBJECTIVE

The incidence of sporadic vestibular schwannoma (VS) has increased significantly over recent decades. The rising incidence of VS has been largely attributed to the increasing use of magnetic resonance imaging (MRI), especially with regard to incidentally diagnosed tumors. However, no study to date has directly investigated this supposed etiology beyond the observation that VS incidence rates have risen in the post-MRI era. Therefore, the primary objective of the current study was to characterize the incidence of head MRIs over the previous two decades in Olmsted County, Minnesota and compare this trend to the incidence of asymptomatic, incidentally diagnosed VS over the same time period.

STUDY DESIGN

Population-based incidence study.

SETTING/PATIENTS

Using the unique resources of the Rochester Epidemiology Project, procedure codes for head MRIs and diagnostic codes for VS among residents of Olmsted County, Minnesota between Jan 1, 1995 and Dec 31, 2016 were retrieved. Incidence rates of head MRI and incidentally diagnosed VS were calculated on a per-year basis.

RESULTS

A total of 43,561 head MRIs among 30,002 distinct persons were identified from 1995 to 2016. The incidence of head MRI significantly increased between 1995 and 2003 (p < 0.001), but remained stable between 2004 and 2016 (p = 0.14). Over the same time interval, 25 cases of incidentally diagnosed VS were identified. The incidence of asymptomatic VS increased over time from 0.72 per 100,000 person-years between 1995 and 1999 to 1.29 between 2012 and 2016 (p = 0.058). No plateauing of incidence rates was observed in incidental tumors over the study period. The size of incidentally diagnosed tumors did not change over the study period (p = 0.93), suggesting that the increasing incidence of asymptomatic tumors is not explained by improved diagnostic capability of more recent MRI studies.

CONCLUSIONS

Despite the plateauing of head MRI incidence rates after 2004, the incidence of asymptotic, incidentally diagnosed VS continued to increase. Our findings suggest that there may be additional contributory etiologies for the rising incidence of VS beyond greater detection alone.

Effect of CO2 laser for the management of primary otosclerosis: A protocol for systematic review and meta-analysis

BACKGROUND

This study will explore the effect and safety of CO2 laser (COL) for the management of patients with primary otosclerosis (PO).

METHODS

The following electronic databases will be searched from inception to the present: PUBMED, EMBASE, The Cochrane Library, Web of Science, PsycINFO, Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, VIP, WANGFANG, and China National Knowledge Infrastructure. No language limitation will be applied. All relevant randomized controlled trials using COL to treat patients with PO will be included. Two researchers will identify studies, collect data and evaluate the risk of bias of each included study independently. Any different views between 2 researchers will be resolved by a third researcher via discussion. Data analysis will be carried out using RevMan 5.3 software.

RESULTS

This study will evaluate the effect and safety of COL for the treatment of PO through hearing gain, tinnitus severity, incidence of intraoperative, health-related quality of life, other morbidities, and adverse events.

CONCLUSION

This study will provide evidence for the effect and safety of COL in patients with PO.

STUDY REGISTRATION NUMBER

INPLASY202040110.

Otosclerosis: Experience With Stapes Surgery

Introduction Otosclerosis is a disorder in which the footplate of the stapes is replaced by an abnormal bone, thereby affecting sound transmission to the inner ear at the level of the oval window. The solution to this condition is to reestablish this mechanism back to normal via the ossicular chain to the inner ear. The aim of stapes surgery is to improve the hearing level to thresholds appropriate enough to obviate the need for hearing aid. The hearing improvement achieved after surgery often lasts for many years. The purpose of the current study was to review our experience and find out the rate of success related to hearing outcomes after stapedotomy. Methods The patients who were operated for otosclerosis between January 2000 and December 2010 at Aga Khan University Hospital, Karachi, Pakistan were included in the study. The charts were reviewed to collect clinical data regarding stapes surgery. The values of speech reception threshold (SRT) were recorded, and the preoperative and postoperative means were compared with a t-test. The bone conduction (BC) and air conduction (AC) thresholds were evaluated at 0.5 kHz, 1.0 kHz, 2.0 kHz, and 3.0 kHz. The preoperative and postoperative means of air-bone gap (AB-gap) were compared with a t-test. The descriptive frequency was calculated to evaluate postoperative AB-gap in individual patients; patients were grouped with a difference of 10 dB of AB-gap. The SPSS Statistics software (IBM, Armonk, NY) was used for statistical analysis. Results A total of 46 patients were included in the study. There were 15 males and 31 females. The mean age was 35 years (range: 20-56). Thirty-three patients had bilateral otosclerosis; two patients had surgery for both ears, taking the total number of ears operated to 48. The mean preoperative AB-gap was 39, while the mean postoperative AB-gap was 11. The means were compared with a t-test and a p-value of <0.05 was considered significant. The means of preoperative and postoperative SRT were 56.25 and 24.27 respectively. Both means were compared with a t-test, and a p-value of <0.05 was considred significant. Postoperatively, 34 ears had AB-gap of 10 dB (70.8%), 11 (22.9%) had within 20 dB, and three (6.3%) had within 30 dB. Conclusions The success rate related to hearing outcomes in patients operated for otosclerosis was excellent and comparable to that found in the current literature. The wide AB-gap noticed in the majority of our patients may represent a delayed presentation to otolaryngologists, which requires further evaluation.

GPER-1 and sex-hormone levels in patients with otosclerosis

OBJECTIVE

Otosclerosis is a widespread disease but the etiopathogenesis is still not fully understood. Hormonal factors especially estrogens are accused in recent years. The study aimed to evaluate the levels of G-protein associated membrane estrogen receptor-1 (GPER-1) and sex-hormones in patients with otosclerosis.

SUBJECT AND METHODS

The study included 60 people (30 otosclerosis patients, 30 control group). Serum sex-hormone (estradiol, progesterone, prolactin and total testosterone) and GPER-1 levels were measured in otosclerosis patients and compared with the normal population. For the otosclerosis group, air conduction and bone conduction thresholds and air-bone gaps were viewed from audiograms and the relationships between hearing and GPER-1 or sex-hormone levels were also investigated.

RESULTS

Sex-hormone levels were not different between the groups. GPER-1 level was significantly lower in the otosclerosis group [3.1353 (0.76-8.21) ng/mL] than the control group [5.4773 (0.96-20.31) ng/mL] (p =0.017). Differential diagnosis with ROC analysis for the GPER-1 level was also significant (p=0.017). GPER-1 level was significantly lower for the females than the males in the otosclerosis group (p=0.043). Serum estradiol, progesterone, and prolactin levels were significantly higher (p=0.02, p =0.029 and p=0.019 respectively) and the GPER-1 level was significantly lower (p= 0.04) in the female patients compared to the female controls. There was no statistically significant relationship between GPER-1 or sex-hormone levels and hearing parameters.

CONCLUSION

GPER-1 level was lower in the otosclerosis patients compared to healthy volunteers and also lower in females than males in the patient group. Female sex-hormone levels were higher and GPER-1 level was lower in the female patient group than the female control group. Neither GPER-1 nor sex-hormone levels were not predictive of hearing levels. These findings indicate that sex-hormones especially estrogen and GPER-1 might have a potential role in the etiopathogenesis of otosclerosis. This is the first study in the literature that investigates the GPER-1 values in otosclerosis.

Immune-Mediated Control of a Dormant Neurotropic RNA Virus Infection

Genomic material from many neurotropic RNA viruses (e.g., measles virus [MV], West Nile virus [WNV], Sindbis virus [SV], rabies virus [RV], and influenza A virus [IAV]) remains detectable in the mouse brain parenchyma long after resolution of the acute infection. The presence of these RNAs in the absence of overt central nervous system (CNS) disease has led to the suggestion that they are viral remnants, with little or no potential to reactivate. Here we show that MV RNA remains detectable in permissive mouse neurons long after challenge with MV and, moreover, that immunosuppression can cause RNA and protein synthesis to rebound, triggering neuropathogenesis months after acute viral control. Robust recrudescence of viral transcription and protein synthesis occurs after experimental depletion of cells of the adaptive immune response and is associated with a loss of T resident memory (T_rm) lymphocytes within the brain. The disease associated with loss of immune control is distinct from that seen during the acute infection: immune cell-depleted, long-term-infected mice display severe gait and motor problems, in contrast to the wasting and lethal disease that occur during acute infection of immunodeficient hosts. These results illuminate the potential consequences of noncytolytic, immune-mediated viral control in the CNS and demonstrate that what were once considered "resolved" RNA viral infections may, in fact, induce diseases later in life that are distinct from those caused by acute infection.IMPORTANCE Viral infections of neurons are often not cytopathic; thus, once-infected neurons survive, and viral RNAs can be detected long after apparent viral control. These RNAs are generally considered viral fossils, unlikely to contribute to central nervous system (CNS) disease. Using a mouse model of measles virus (MV) neuronal infection, we show that MV RNA is maintained in the CNS of infected mice long after acute control and in the absence of overt disease. Viral replication is suppressed by the adaptive immune response; when these immune cells are depleted, viral protein synthesis recurs, inducing a CNS disease that is distinct from that observed during acute infection. The studies presented here provide the basis for understanding how persistent RNA infections in the CNS are controlled by the host immune response, as well as the pathogenic consequences of noncytolytic viral control.

The CaV1.2 L-type calcium channel regulates bone homeostasis in the middle and inner ear

Bone remodeling of the auditory ossicles and the otic capsule is highly restricted and tightly controlled by the osteoprotegerin (OPG)/receptor activator of nuclear factor kappa-Β ligand (RANKL)/receptor activator of nuclear factor kappa-Β (RANK) system. In these bony structures, a pathological decrease in OPG expression stimulates osteoclast differentiation and excessive resorption followed by accrual of sclerotic bone, ultimately resulting in the development of otosclerosis, a leading cause of deafness in adults. Understanding the signaling pathways involved in maintaining OPG expression in the ear would shed light on the pathophysiology of otosclerosis and other ear bone-related diseases. We and others previously demonstrated that Ca2+ signaling through the L-type CaV1.2 Ca2+ channel positively regulates OPG expression and secretion in long bone osteoblasts and their precursor cells in vitro and in vivo. Whether CaV1.2 regulates OPG expression in ear bones has not been investigated. We drove expression of a gain-of-function CaV1.2 mutant channel (CaV1.2TS) using Col2a1-Cre, which we found to target osteochondral/osteoblast progenitors in the auditory ossicles and the otic capsule. Col2a1-Cre;CaV1.2TS mice displayed osteopetrosis of these bones shown by μCT 3D reconstruction, histological analysis, and lack of bone sculpting, findings similar to phenotypes seen in mice with an osteoclast defect. Consistent with those observations, we found that Col2a1-Cre;CaV1.2TS mutant mice showed reduced osteoclasts in the otic capsule, upregulated mRNA expression of Opg and Opg/Rankl ratio, and increased mRNA expression of osteoblast differentiation marker genes in the otic capsule, suggesting both an anti-catabolic and anabolic effect of CaV1.2TS mutant channel contributed to the observed morphological changes of the ear bones. Further, we found that Col2a1-Cre;CaV1.2TS mice experienced hearing loss and displayed defects of body balance in behavior tests, confirming that the CaV1.2-dependent Ca2+ influx affects bone structure in the ear and consequent hearing and vestibular functions. Together, these data support our hypothesis that Ca2+ influx through CaV1.2TS promotes OPG expression from osteoblasts, thereby affecting bone modeling/remodeling in the auditory ossicles and the otic capsule. These data provide insight into potential pathological mechanisms underlying perturbed OPG expression and otosclerosis.

Cochlear implantation in far-advanced otosclerosis: hearing results and complications

Severe forms of otosclerosis known as far-advanced otosclerosis (FAO) can lead to severe to profound sensorineural hearing loss and can justify cochlear implantation. Because of the pathophysiology of otosclerosis, patients implanted for FAO may experience an increased rate of complications, such as facial nerve stimulation or electrode dislocation, and may have poorer hearing outcomes than expected. This retrospective study aimed to compare cochlear implantation hearing outcomes, surgical difficulties and complications in FAO patients versus non-FAO patients. Moreover, we evaluated whether high resolution computed tomography (CT scan) findings were predictive of perioperative problems, complications and hearing outcomes. FAO patients were diagnosed based on medical history, examination and CT scan. Thirty-five ears from FAO patients were compared to 38 control ears. Audiometric results were assessed at least 12 months after implantation by pure tone average, speech reception threshold, monosyllabic and disyllabic word recognition score (WRS) and Central Institute for the Deaf (CID) sentences test. Complications and surgical difficulties were compiled. CT scan findings were categorised within 3 grades of otosclerotic extension. No significant difference was found between FAO and non-FAO hearing outcomes, except that monosyllabic WRS were lower for FAO patients, especially those who underwent previous stapedotomy. Facial nerve symptomatology occurred in 8.6% of FAO patients; among these, one required explantation-reimplantation surgery. 86% of FAO implanted patients had retrofenestral extension on CT. These were associated with poorer disyllabic WRS (51% vs 68%, p < 0.05) than those with only fenestral involvement. Although not significant, high grade of severity on CT tended to be associated with surgical difficulties and complications. Cochlear implantation in FAO patients is an effective treatment technique. Though the overall complication rate is low, it tends to be higher in cases of severe extension on CT. Patient counselling should be adjusted accordingly.

Wideband tympanometry and absorbance measurements in otosclerotic ears

OBJECTIVES

This study aimed to assess absorbance using a thorough analysis of individual points of its plot in ears with intraoperatively confirmed otosclerosis. To the best of our knowledge, until recently no analyses have been performed that concerned the shape of an absorbance plot and a detailed analysis of its individual points. This study is the first to undertake such an issue.

METHODS

A total of 77 otosclerotic ears were included in the study. Pure tone audiometry, low frequency tympanometry, and wide band tympanometry including absorbance were performed preoperatively. The average patients' age in the group was 43.49 years (standard deviation = 10.44). Individual points of absorbance plot were thoroughly analyzed. Parameters were analyzed, such as resonance frequency; number of peaks; maximum absorbance (Height); and plot Width at the following Heights: 1/3, 1/2, and 2/3 (Width1/3, Width1/2, Width2/3, respectively), as well as associated absorbance parameters and frequencies.

RESULTS

Data analysis revealed five different types of absorbance plots. Numerous statistically significant differences regarding the parameters of individual points of the plots were found among the distinguished types.

CONCLUSIONS

There are five types of absorbance plots in otosclerotic ears: type I, characterized by two distinct peaks, closely resembling normal ear absorbance plot; type II with a single distinct peak reaching high values of absorbance; type III with reduced absorbance for frequencies <2000 Hz; type IV with reduced absorbance for all frequencies; and type V with reduced absorbance for frequencies >2000 Hz. Absorbance measurements may play an important role in the diagnostics of otosclerosis; however, further research is necessary in this area.

LEVELS OF EVIDENCE

4 Laryngoscope, 129:E365-E376, 2019.

Significance of internal auditory canal diverticula in ears with otosclerosis

BACKGROUND

Diverticula in the internal auditory canal (IAC) have been reported in ears with otosclerosis.

OBJECTIVE

We evaluated hearing levels and vascular activity in ears with otosclerosis with and without IAC diverticula and clarify the significance of IAC diverticula.

MATERIALS AND METHODS

Sixty-one ears from 54 patients who underwent stapes surgery for otosclerosis [fenestral (48 ears) and retrofenestral (13 ears) groups] were included in the present study. Preoperative hearing levels on pure tone audiometry (PTA) and intraoperative measurements of blood flow were compared between the groups.

RESULTS

A total of 24 of 61 ears (39.3%) showed IAC diverticula, significantly higher than the frequency in ears without otosclerosis (3.7%). No significant differences in air- and bone-conduction thresholds on PTA were evident between ears with and without IAC diverticula in each group. Ears without IAC diverticula tended to show higher blood flow in the area anterior to the oval window than ears with IAC diverticula, but the difference was not significant.

CONCLUSIONS

The incidence of the IAC diverticula in otosclerosis was significantly higher than in cases without otosclerosis. The existence of IAC diverticula was not evidently related to the severity of the disease from the perspective of hearing level and vascular activity.

Stapes surgery in patients with a small air-bone gap

The objective of this study was to determine hearing outcomes in patients undergoing stapes surgery with a preoperative air-bone gap (ABG) <21.25 dB. Patients with a unilateral or bilateral preoperative ABG <21.25 dB undergoing primary stapes surgery were identified from a database of all stapes surgeries performed in a tertiary center over 15 years. A total of 254 ears met the inclusion criteria. The primary outcome measure was the degree of closure of the preoperative ABG. A secondary outcome measure was improvement in bone-conduction thresholds at 4 kHz. All patients underwent stapes surgery under local anesthesia. Ossicular reconstruction was achieved using a SMart 360 nitinol fluoroplastic piston (Gyrus ACMI, Inc.; Southborough, Mass.), and complete posterior crurotomy was performed with a KTP laser. Hearing was assessed with clinical voice testing immediately postoperatively and with pure-tone audiometry at 6 weeks postoperatively. A total of 248 ears (97.6%) demonstrated ABG closure to <10 dB. Bone-conduction thresholds showed an increase in 114 (44.9%), no change 74 (29.1%), and a decrease in 66 (26.0%). There is a slight increase in the risk of stapes mobilization in ears with a small ABG when compared to those with larger ABGs; however, this can be overcome by using a laser-assisted technique in combination with good surgical experience. The benefit in terms of hearing aid avoidance and the restoration of symmetrical hearing is both achievable and significant for the patient.

Impact of Imaging in Management of Otosclerosis

The use of imaging in otosclerosis for diagnosis, preoperative assessment, and follow-up has the potential to give the clinician an additional tier of patient evaluation and validation of diagnosis. Before stapes surgery, imaging may help avoid unnecessary middle ear explorations in nonotosclerotic cases, prevent potential complications, and assist in appropriate patient counseling regarding management expectations. Postoperatively, following unsuccessful air-bone gap closure in stapes surgery or conductive hearing deterioration following initial successful closure of the air bone gap, imaging can be used to determine the prosthesis position in the middle ear.

Otosclerosis: An update on diagnosis and treatment

Otosclerosis is a complex and progressive disease of pathological bone remodeling that affects the otic capsule of the temporal bone, resulting in hearing loss. Although traditional diagnostic methods are still used, improvements in technology and research have paved the way for additional diagnostic techniques and advancements. The traditional treatment of otosclerosis, stapes surgery, is now being augmented or replaced by innovations in hearing aid technology and cochlear implants. Earlier diagnosis of otosclerosis can occur through understanding of the cause, risk factors, and current diagnostic testing.

Pedigree Analysis and Audiological Investigations of Otosclerosis: An Extended Family Based Study

Background and Objectives

To analyse the audiometric profile and the pedigree of a large family with otosclerosis to understand the inheritance pattern and its implication in clinical management of the disease.

Subjects and Methods

Pedigree analysis was performed on the basis of family history and audiometric tests. Pure tone audiometry, tympanometry, and acoustic reflexes were evaluated for the family members. Audiometric analysis was also carried out for the individuals who have already underwent corrective surgery at the time of study.

Results

Out of 112 family members, 17 were affected individuals, and 11 of them were surgically confirmed. Hearing loss (HL) started unilaterally and progressed to bilateral form. Otosclerosis was presented in early 20’s in the first and second generations but it was delayed to mid-late 30’s in the fourth generation. An affected female was diagnosed with otosclerosis during her pregnancy. Though the disease was familial, a mother of four affected offspring in this family did not develop otosclerosis until she died at the age of 84.

Conclusions

The five-generation family, which was analysed in the present study, exhibited autosomal dominant inheritance of otosclerosis with reduced penetrance. Bilateral HL and pregnancy-aggravated otosclerosis were observed in this family. It was found for the first time that the age of onset of the disease delayed in the successive generations. The current study indicated the importance of detailed pedigree analysis for better clinical management of otosclerosis.