Fluoride therapy for cochlear otosclerosis? an audiometric and computerized tomography evaluation

Conservative Otosclerosis Treatment With Sodium Fluoride and Other Modern Formulations: A Systematic Review

Otosclerosis, also known as otospongiosis, is a primary osteodystrophy of the otic capsule of the inner ear and one of the leading causes of deafness in adults. The rationale for medical therapy for otospongiosis is to slow down and eventually stop the phase of bone resorption. Conservative treatments include sodium fluoride (NaF), bisphosphonates, and other modern medicines. A systematic review of the existing and published articles and books until April 2021 has been conducted in Medscape, Google Scholar, PubMed, and other databases using appropriate terms. According to the results of the research, the administration of NaF for a period of at least six months stabilizes hearing thresholds (HTs), improves vestibular symptoms, and delays the worsening of tinnitus. The administration of bisphosphonates for a period of at least six months showed significant percentage differences in the improvement of hearing loss, dizziness, and tinnitus remission. In the already existing double-blind studies that were evaluated, groups of patients treated with bisphosphonates for at least 24 months showed greater stabilization of the mean air and bone conduction thresholds than groups of patients treated with a placebo. The new modern medications have not yet been widely administered clinically to draw useful conclusions, although the test results of some of their use are quite encouraging.

Effects of otosclerosis and stapedotomy on vestibular-evoked myogenic potentials

OBJECTIVE

Limited data are available on the effects of otosclerosis and otosclerosis surgery on the utricle and saccule. This study aimed to determine the effect of otosclerosis and stapedotomy on vestibular-evoked myogenic potentials.

METHODS

This retrospective study included 16 otosclerosis patients and 18 controls. Thirty-two ears of 16 patients with otosclerosis were divided into 2 groups based on whether the ear had been operated on or not. All patients and subjects underwent 500 Hz air- and bone-conducted ocular and cervical vestibular-evoked myogenic potentials testing.

RESULTS

Overall comparison of response rates showed a significant difference among the groups. Further statistical tests showed that this difference arose from differences between both operated and unoperated groups and the control group, for air-conducted cervical and ocular vestibular-evoked myogenic potentials.

CONCLUSION

Otosclerosis and stapedotomy may affect the elicitability of vestibular-evoked myogenic potentials. Otosclerosis is associated with lower response rates for air-conducted ocular and cervical vestibular-evoked myogenic potentials, regardless of whether operated on. Having been operated on does not significantly increase the response rate of air-conducted vestibular-evoked myogenic potentials.

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: Incidence of Positive Findings on High-Resolution Computed Tomography and Their Correlation to Audiological Test Data

Objectives:

Computed tomographic (CT) scanning with slices of 1 mm or more has not been sufficient to demonstrate otosclerotic foci in most cases to date.

Methods:

We investigated the validity of CT scans with a 0.5-mm cubical scan technique, with and without planar reconstruction, and correlated these findings with audiological data. Forty-four temporal bone CT scans from 30 patients with conductive or mixed hearing loss were evaluated.

Results:

Otosclerotic foci were visualized in 74% of the cases. With reconstruction at the workstation, the sensitivity increased to 85%. Whereas in fenestral otosclerosis a correlation was found between the size of the focus and the air-bone gap, no correlation was seen between the size of the focus and bone conduction thresholds with cochlear involvement. Otosclerotic foci in patients treated with sodium fluoride were smaller than those in patients without treatment. This finding may indicate a beneficial effect of sodium fluoride on otosclerotic growth.

Conclusions:

High-resolution CT scans are a valid tool that can be used to confirm, localize, and determine the size of clinically suspected otosclerotic foci.

Etiologic diagnosis of sensorineural hearing loss in adults

OBJECTIVE: To determine the etiology of adult-onset sensorineural hearing loss.

STUDY DESIGN AND SETTING: This is a prospective cohort study of 60 adult subjects with bilateral sensorineural hearing loss of no obvious etiology by medical history and physical examination. These patients were evaluated at an academic medical center and underwent evaluation by high-resolution computed tomography of the temporal bone, autoimmune panel, and DNA testing for mutations of both the GJB2 gene and the mitochondrial DNA (1555A>G and 7445A>G).

RESULTS: An etiologic diagnosis was achieved in 6 patients: cochlear otosclerosis, 1 case; dilated vestibular aqueduct, 1 case; a mitochondrial DNA 7445A>G mutation, 3 cases; and a mitochondrial DNA 1555A>G mutation, 1 case.

CONCLUSION: This result underscores the importance of a search for the etiology of a hearing deficit in adult patients. There are specific interventions now available for the management of hearing-impaired patients with cochlear otosclerosis and mitochondrial DNA mutations.

Quantitative assessment of vestibular otopathology in otosclerosis: A temporal bone study

OBJECTIVES/HYPOTHESIS

To determine if peripheral vestibular otopathology is present in human temporal bones with otosclerosis.

STUDY DESIGN

Comparative human temporal bone study.

METHODS

Seventy-four human temporal bones from 46 subjects with otosclerosis (mean age of 61 ± 18 years) and 20 within histologically normal limits from 17 subjects (mean age of 59 ± 14 years) were included in this study. Temporal bones with otosclerosis were divided into those with and without endosteal involvement. Using differential interference contrast microscopy at 1008× magnification, type I and type II vestibular hair cell counts were performed on each vestibular sense organ in which the neuroepithelia was oriented perpendicular to the plane of section. The organ-specific cell densities (cells/0.01 mm(2) surface area) were compared between the groups with and without endosteal involvement, and also compared to counts in the nonotosclerosis control group using Student's t-test.

RESULTS

Mean type I and type II hair cell densities of all vestibular structures in the group with endosteal involvement were significantly lower compared to the group without endosteal involvement. Mean type I and type II hair cell densities of all vestibular structures in the group with endosteal involvement were also significantly lower compared to the control group, but they were not in the group without endosteal involvement compared to the control group.

CONCLUSION

Endosteal involvement of otosclerotic foci is associated with vestibular hair cell loss that may contribute to the vestibular symptoms in otosclerosis.

LEVEL OF EVIDENCE

N/A. Laryngoscope, 126:E118-E122, 2016.

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.

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.

Imaging Evaluation in Otosclerosis: Single Photon Emission Computed Tomography and Computed Tomography

Objectives:

The aim of our study was to demonstrate the utility of diphosphonate bone single photon emission computed tomography (SPECT) in diagnosing otosclerosis and to correlate the findings from SPECT with age, gender, and sensorineural hearing loss. We also evaluated the ability of high-resolution computed tomography (HR-CT) in detecting otospongiotic and otosclerotic foci and correlated the HR-CT findings with the SPECT results.

Methods:

Seventy-three subjects with surgically confirmed otosclerosis underwent SPECT, and 45 of the 73 patients also underwent HR-CT of the petrous bones.

Results:

In the patient sample examined in this study, SPECT demonstrated a sensitivity of 95.2% and a specificity of about 96.7%. By correlating the SPECT findings, we found an inverse relationship between bone radioactivity and age (ie, greater disease activity in younger patients) and a direct relationship between bone radioactivity and the severity of sensorineural impairment in younger patients. In the 45 patients who also underwent HR-CT, the sensitivity of HR-CT (58%) was lower than that of SPECT, and the comparison between SPECT activity and the HR-CT findings (fenestral or retrofenestral type) demonstrated a statistically significant correlation between the morphological finding of bone demineralization (pericochlear foci) and a high uptake index.

Conclusions:

The use of SPECT seems to be highly effective in differentiating normal from pathological petrous bone. It also provides a quantitative evaluation of disease activity and shows a significant correlation with bone demineralization revealed by HR-CT.

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.

[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.