Otospongiosis and sodium fluoride. A blind experimental and clinical evaluation of the effect of sodium fluoride treatment in patients with otospongiosis

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.

Review of Pharmacotherapy for Tinnitus

Various medications are currently used in the treatment of tinnitus, including anesthetics, antiarrhythmics, anticonvulsants, antidepressants, antihistamines, antipsychotics, anxiolytics, calcium channel blockers, cholinergic antagonists, NMDA antagonists, muscle relaxants, vasodilators, and vitamins. To date, however, no medications have been specifically approved to treat tinnitus by the US Food and Drug Administration (FDA). In addition, medicines used to treat other diseases, as well as foods and other ingested materials, can result in unwanted tinnitus. These include alcohol, antineoplastic chemotherapeutic agents and heavy metals, antimetabolites, antitumor agents, antibiotics, caffeine, cocaine, marijuana, nonnarcotic analgesics and antipyretics, ototoxic antibiotics and diuretics, oral contraceptives, quinine and chloroquine, and salicylates. This review, therefore, describes the medications currently used to treat tinnitus, including their mechanisms of action, therapeutic effects, dosages, and side-effects. In addition, this review describes the medications, foods, and other ingested agents that can induce unwanted tinnitus, as well as their mechanisms of action.

Magnetic resonance imaging in the evaluation of clinical treatment of otospongiosis: a pilot study

OBJECTIVES

To evaluate the applicability of magnetic resonance imaging (MRI) as a method for monitoring the activity of otospongiotic lesions before and after clinical treatment.

STUDY DESIGN

Prospective, randomized, controlled, double-blind study.

SETTING

One single tertiary care institution in a large, cosmopolitan city.

METHODS

Twenty-six patients (n = 42 ears) with clinical, audiometric, and tomographic diagnosis of otosclerosis were enrolled. If computed tomography (CT) demonstrated active lesions, these patients underwent MRI to detect otospongiotic foci, seen as areas of gadolinium enhancement. Patients were divided into 3 groups and received treatment with placebo, sodium alendronate, or sodium fluoride for 6 months. After this period, clinical and audiometric evaluations and a second MRI were performed. Each MRI was evaluated by both a neuroradiologist and an otolaryngologist in a subjective (visual) and objective (using specific eFilm Workstation software) manner.

RESULTS

Otospongiosis was most predominantly identified in the region anterior to the oval window, and this site was reliable for comparing pre- and posttreatment scans. The patients in the alendronate and sodium fluoride groups had MRI findings that suggested a decrease in activity of otospongiotic lesions, more relevant in the alendronate group. These findings were statistically significant for both subjective and objective MRI evaluations.

CONCLUSIONS

MRI shows higher sensitivity than clinical or audiometric assessment for detecting reduction in activity of otospongiosis. The objective MRI evaluation based on software analysis was the most accurate method of monitoring clinical treatment response in otospongiosis.

Third-generation bisphosphonates for treatment of sensorineural hearing loss in otosclerosis

OBJECTIVE

To evaluate hearing outcomes in patients treated with third generation bisphosphonates for otosclerosis-related sensorineural hearing loss (SNHL).

HYPOTHESIS

Otosclerosis is a disease of abnormal bone remodeling in the otic capsule. In recent years, third generation bisphosphonates, with more powerful anti-resorptive properties and increased bone affinity, have demonstrated effectiveness in the treatment of osteoporosis and other metabolic bone diseases. We hypothesized that newer generation bisphosphonates, such as risedronate and zoledronate, would be effective in slowing the progression of SNHL in patients with otosclerosis.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary referral center, ambulatory care.

INTERVENTIONS

Risedronate or zoledronate administration.

MAIN OUTCOME MEASURES

Bone conduction pure tone threshold averages (PTAs) and word recognition (WR) scores were examined for each ear before and after bisphosphonate treatment. Criteria for significant change were defined as greater than 10 decibels in PTA or between 4% and 18% in WR based on binomial variance.

RESULTS

All 10 patients had audiometric progression of SNHL in the pretreatment monitoring interval and 12 ears met criteria for significant progression. All 10 patients (19 ears) showed at least no significant progression of SNHL (i.e., stabilization) at an average follow-up of 13 months. Two patients (3 ears) showed improvement by defined audiometric criteria. There were no major complications.

CONCLUSION

Treatment with zoledronate or risedronate stabilized progressive SNHL related to otosclerosis in this small group of patients. Further evaluation of third-generation bisphosphonate treatments is warranted.

Perspectives of pharmacological treatment in otosclerosis

To review our current knowledge of the pathologic bone metabolism in otosclerosis and to discuss the possibilities of non-surgical, pharmacological intervention. Otosclerosis has been suspected to be associated with defective measles virus infection, local inflammation and consecutive bone deterioration in the human otic capsule. In the early stages of otosclerosis, different pharmacological agents may delay the progression or prevent further deterioration of the disease and consecutive hearing loss. Although effective anti-osteoporotic drugs have become available, the use of sodium fluoride and bisphosphonates in otosclerosis has not yet been successful. Bioflavonoids may relieve tinnitus due to otosclerosis, but there is no data available on long-term application and effects on sensorineural hearing loss. In the initial inflammatory phase, corticosteroids or non-steroidal anti-inflammatory drugs may be effective; however, extended systemic application may lead to serious side effects. Vitamin D administration may have effects on the pathological bone loss, as well as on inflammation. No information has been reported on the use of immunosuppressive drugs. Anti-cytokine targeted biological therapy, however, may be feasible. Indeed, one study on the local administration of infliximab has been reported. Potential targets of future therapy may include osteoprotegerin, RANK ligand, cathepsins and also the Wnt-β-catenin pathway. Finally, anti-measles vaccination may delay the progression of the disease and potentially decrease the number of new cases. In conclusion, stapes surgery remains to be widely accepted treatment of conductive hearing loss due to otosclerosis. Due to lack of solid evidence, the place of pharmacological treatment targeting inflammation and bone metabolism needs to be determined by future studies.

Cochlear otosclerosis

PURPOSE OF REVIEW

The aim of this study is to summarize current advances in research and clinical aspects of cochlear otosclerosis.

RECENT FINDINGS

Recent studies have revealed that otosclerosis is a process of bone remodeling that is unique to the otic capsule only. Even though no obvious bone remodeling is seen in the otic capsule under normal conditions, remodeling starts when some molecular factors trigger the capsule in certain patients who have genetic and/or environmental tendencies.

SUMMARY

Cochlear otosclerosis is defined as otosclerosis located in the otic capsule involving the cochlear endosteum and causing sensorineural hearing loss or mixed-type hearing loss. It has been clearly shown that, when otosclerosis is sufficiently severe to involve the cochlear endosteum, it usually fixes the stapes as well.

The etiology of otosclerosis: a combination of genes and environment

Otosclerosis is a common form of hearing loss characterized by abnormal bone remodeling in the otic capsule. It is a complex genetic disease, caused by a combination of genetic and environmental factors. During the past decade, several attempts have been made to identify factors for otosclerosis. This review provides an overview of the current understanding of the etiology of otosclerosis and describes the genetic and environmental factors that have been implicated in the disease. Environmental factors include fluoride and viral factors, particularly measles. Genetic association studies for otosclerosis have reported several associations of genetic variants that influence the risk of disease, mainly involving bone remodeling pathways, although their individual risk contributions are small. Rare monogenic forms of otosclerosis also exist, which are caused by a mutation in a single gene leading to a clear familial segregation of the disease. Linkage analysis of large otosclerosis families has led to the identification of seven loci, and recently evidence was found that T cell receptor beta is a gene responsible for familial otosclerosis, suggesting an underlying immunological pathway. However, this might also represent an autoimmune process, a hypothesis that is supported by other data as well. In conclusion, a variety of pathways have been identified to be involved in the development of otosclerosis, showing that distinct mechanisms involving both genetic and environmental risk factors can influence and contribute to a similar disease outcome.

Sodium fluoride in otosclerosis treatment: review

OBJECTIVES

To review the current literature on the use of sodium fluoride in the treatment of otosclerosis.

DESIGN

A literature review was conducted, searching the Medline and PubMed database from 1966 to 2009, using the terms 'otosclerosis' and 'fluoride'. Article abstracts were reviewed and relevant full articles acquired.

RESULTS

There has been only one double-blind, placebo-controlled trial of the use of sodium fluoride in otosclerosis patients, and this found a reduced incidence of deterioration in hearing after two years in the treatment group. Several case-control series have described a hearing benefit in the sodium fluoride treated group. Treatment doses vary greatly, and there is no evidence regarding the optimum duration of treatment.

CONCLUSIONS

There is low quality evidence suggesting that sodium fluoride may be of benefit to preserve hearing and reduce vestibular symptoms in patients with otosclerosis.

Otosclerosis 2: the medical management of otosclerosis

The rationale for medical therapy for otospongiosis is to slow down and eventually stop the phase of bone resorption. There is some increase in the incidence of stapedial otospongiosis in a low-fluoride area compared with a high-fluoride area. Sodium fluoride treatment has a role to play in preventing the onset and progression of hearing loss in patients suffering from otosclerosis. Sodium fluoride therapy has been shown to have some beneficial effect on dizziness associated with otosclerosis. In view of the possibility of systemic side effects of sodium fluoride therapy, a regular follow up of patients is warranted. Biphosphonates can be used as an alternative treatment to sodium fluoride in cases where the patient is intolerant to sodium fluoride therapy. Hearing aid is also a treatment option, but it does not halt the disease process.

Glucocorticoids Inhibit Diastrophic Dysplasia Sulfate Transporter Activity in Otosclerosis by Interleukin-6

HYPOTHESIS/OBJECTIVE

Otosclerosis is a bone remodeling disorder localized to the otic capsule and associated with inflammation. In vitro, increased activity of the diastrophic dysplasia sulfate transporter (DTDST), which is implicated in bone metabolism, has been reported. Because glucocorticoids modulate the bone turnover and inhibit inflammatory processes, we investigated the effect of dexamethasone (Dex) on interleukin-6 and DTDST in otosclerosis.

STUDY DESIGN

The authors conducted a prospective, case-control study.

MATERIALS AND METHODS

Primary cell cultures were obtained from stapes and external auditory canals in otosclerosis (n = 21) and control patients (n = 18). Assays with [H]Dex evaluated specific binding sites in otosclerotic and control stapes. The effects of Dex (10 to 10 M) and RU486 (10 M), a glucocorticoid antagonist, were studied on DTDST activity by sulfate uptake. IL-6 secretion was measured in culture media before and after Dex (10 M, 24 hours). The effect of IL-6 (10 M, 24 hours) was assessed on DTDST activity in control stapes.

RESULTS

: The number of specific Dex-binding sites was similar in all stapedial cultures. Dex inhibited DTDST activity (19.4 +/- 1.02 vs. 29.4 +/- 3.94 pmol/microg prot/5 minutes) only in otosclerotic stapes. This effect was dose-dependent, antagonized by RU 486 and only observed 24 hours after Dex exposure. Interleukin (IL)-6 stimulated DTDST activity in normal stapes, whereas Dex inhibited IL-6 production only in otosclerotic stapes.

CONCLUSION

Dex inhibits the DTDST activity, at least in part, through a reduction of IL-6 secretion only in otosclerotic cells. This effect is mediated through the glucocorticoid receptors and may lead to the reduction of bone turnover.

Cochlear implantation in 53 patients with otosclerosis: demographics, computed tomographic scanning, surgery, and complications

OBJECTIVES

To collect data from a large number of cochlear implant recipients with otosclerosis and to make an assessment of these patients' clinical characteristics, computed tomographic scans, surgical findings, and complications, and to quantify the occurrence of postoperative facial nerve stimulation.

STUDY DESIGN

Retrospective multicenter study.

PATIENTS

Fifty-three patients with otosclerosis from four cochlear implant centers in the United Kingdom and The Netherlands were reviewed. Sixty surgical procedures were performed in these patients: 57 devices were placed in 56 ears.

RESULTS

The computed tomographic imaging demonstrated retrofenestral (cochlear) otosclerotic lesions in the majority of patients. Although not statistically significant, the extent of otosclerotic lesions on the computed tomographic scan as categorized in three types tends to be greater in patients with rapidly progressive hearing loss, in patients in whom there is surgically problematic insertion of the electrode array, and in patients with facial nerve stimulation. In four patients, revision surgery had to be performed. Twenty of 53 (38%) patients experienced facial nerve stimulation at various periods postoperatively.

CONCLUSION

Cochlear implant surgery in patients with otosclerosis can be challenging, with a relatively high number of partial insertions and misplacements of the electrode array demanding revision surgery. A very high proportion of patients experienced facial nerve stimulation mainly caused by the distal electrodes. This must be discussed with patients preoperatively.

Increased Activity of the Diastrophic Dysplasia Sulfate Transporter in Otosclerosis and Its Inhibition by Sodium Fluoride

HYPOTHESIS

This study investigates the function of the diastrophic dysplasia sulfate transporter (DTDST) in otosclerotic bone and the effect on it of sodium fluoride (NaF).

BACKGROUND

Otosclerosis is a localized bone dystrophy with increased bone turnover. DTDST is implicated in the regulation of the bone turnover.

MATERIALS AND METHODS

Primary cultures of cells were obtained from the stapes and external auditory canal (EAC) of 26 patients with otosclerosis and from nine control patients. Sulfate uptake was quantified under basal conditions and with NaF. The NaF signaling pathways were investigated using forskolin and verapamil.

RESULTS

The relative initial rates of sulfate uptake and the apparent Vmax values were: otosclerotic stapes > EAC > control stapes = control EAC. The sulfate uptake by the otosclerotic stapes was correlated with the loss of sensorineural hearing. The amounts of DTDST mRNA (RNase protection assay) in the four subgroups did not differ. NaF (10(-6)M, 1 hr) inhibited sulfate uptake by the otosclerotic stapes and EAC cells but not by control samples.

CONCLUSION

The authors believe that whether the increased DTDST activity is a cause or an effect of otosclerosis, it appears to be a specific target for NaF treatment.

[Possible benefits of calcitonin in the treatment of otosclerosis]

This study shows the results obtained after treatment with intranasal calcitonin in 23 patients (36 ears) suffering from otosclerosis. 19.4% showed a hearing improvement upper of 10 dB. The gain was 32 dB in air conduction thresholds and 23 dB. In bone conduction. Tinnitus disappeared in 25% of cases suffering from tinnitus. Calcitonin tolerance was good, 8.7% of patients reported migraine. Authors recommended additional studies in order to evaluate the efficacy of this drug in the treatment of otosclerosis.

Pathophysiology of otosclerosis

OBJECTIVE

To review current knowledge of the pathophysiology of otosclerosis and to review hypotheses for the amelioration of this disease.

DATA SOURCES

Review of the literature and experimental observations by the authors.

CONCLUSIONS

Otosclerosis is a localized disease of bone remodeling within the otic capsule of the human temporal bone. Unlike other similar bone diseases, it does not occur outside of the temporal bone. These lesions seem to begin by resorption of stable otic capsule bone in adults, followed by a reparative phase with bone deposition. There are clearly genetic factors that lead to this disease, but measles virus infection and autoimmunity also may play contributing roles. Surgical correction of the conductive hearing loss is highly effective, but nonsurgical intervention has not yet been shown to prevent or slow the disease. Of the factors that may inhibit this process, fluorides, cytokine inhibitors, and bisphosphonates, third-generation bisphosphonates appear to hold the most promise.

Etidronate for the Neurotologic Symptoms of Otosclerosis: Preliminary Study

The efficacy of etidronate, a Bisphosphonate, was assessed as a treatment for the inner ear symptoms of otosclerosis in a retrospective case review of 896 patients diagnosed with otosclerosis, with primary complaints of dizziness, hearing loss, tinnitus or Meniere's syndrome. The diagnosis of otosclerosis was based on small-pixel computed tomography of the temporal bones. Of the 896 patients placed on an etidronate protocol, 545 were followed for more than six months and were analyzed. The symptomatic response to etidronate, as well as audiologic and computerized rotary chair results were used in the assessment. Patients who were previously on sodium fluoride were separately analyzed. In this preliminary study etidronate appeared to be an effective treatment for the neurotologic symptoms of otosclerosis. Prospective blinded efficacy studies of the bisphosphonates in the treatment of otosclerosis should be undertaken.

CT screening for temporal bone abnormalities in idiopathic bilateral sensorineural hearing loss

Bilateral sensorineural hearing loss can be caused by a variety of temporal bone abnormalities including primary cochlear otosclerosis, local and systemic bony diseases and some metabolic conditions. These may be identified using computerized tomography (CT), with attenuation recordings taken across the cochlear capsule (CT densitometry). Eighty patients with bilateral sensorineural hearing loss were screened over a period of six and a half years using this technique, and only three cases (3.8 per cent) of treatable disease were detected. Positive yields may be increased by screening selected cases with other clinical or biochemical stigmata of temporal bone disease.

Electromagnetic stimulation as a treatment of tinnitus: a pilot study

This paper reports the results of a study to determine whether pulsed electromagnetic stimulation, applied over the mastoid bone, caused an improvement in the level of tinnitus in long-standing tinnitus sufferers. Fifty-eight patients from the Liverpool Tinnitus Association volunteered to take part in a double-blind placebo controlled trial. Active and placebo devices were randomly allocated to these patients on their first visit. At the end of one week of treatment, each patient noted whether their tinnitus had completely disappeared, was improved, unchanged or made worse by the treatment Forty-five per cent of the patients who completed the trial were improved by the active device, but only 9% by placebo (P = 0.0013, Mann-Whitney test). We suggest that electromagnetic stimulation may be an effective treatment in some tinnitus sufferers.