Intratympanic gentamicin for Meniere's disease: short- and long-term follow-up of two regimens of treatment

A Randomised Controlled Trial Comparing Intratympanic Gentamicin with Methylprednisolone in Meniere's Disease with Good Hearing

A randomized prospective parallel group trial was done to compare the efficacy of intratympanic low dose gentamicin with methylprednisolone in treating intractable unilateral Meniere's disease with serviceable hearing.

STUDY DESIGN

Randomised prospective parallel group trial.

SETTING

Tertiary care centre in South India.

SUBJECTS AND METHODS

Forty patients with unilateral Meniere's disease and serviceable hearing with vertigo following 6 months of conservative therapy were enrolled between November 2018 and March 2020. Twenty patients were administered with one dose of intratympanic Gentamicin (40 mg/ml) and the other half were given intratympanic Methylprednisolone (40 mg/ml, 4 injections given on alternate days). Pure tone audiogram, speech discrimination score, number of vertigo episodes, dizziness handicap inventory, tinnitus handicap inventory and functional scores were compared before treatment, 3 months later and up to 24 months. There was no significant difference between the two treatments with regard to short term as well as long term DHI scores, THI scores, Functional level score and average pure tone audiogram of patients. In patients with unilateral Meniere's disease who have good hearing, one dose of Gentamicin had equivalent effect to that of four doses of Methylprednisolone in vertigo and tinnitus control, hearing preservation and quality of life.

Low Dose Intratympanic Gentamicin in Ménière’s Disease

Intratympanic gentamicin has become an accepted standard of care for Ménière's disease. But there still exists controversies regarding the dosing protocol as well as the drug concentration for optimum control of vertigo and hearing preservation. To determine if 20 mg of intratympanic gentamicin administered once a month for a maximum of 2 months can alleviate intractable vertigo caused by definite Ménière's disease with hearing preservation. Once diagnosed with definite Ménière's disease as per AAO-HNS criteria, the patient was given 0.5 ml of 40 mg/ml intratympanic gentamicin. Follow-up was done at 1-month and 6-month post-treatment. If at 1-month review patient continued to have vertigo one more dose of intratympanic gentamicin was administered. Thirty-two patients were included in the study. Seventeen patients (53.1%) received one dose and 15 patients (46.9%) received two doses of intratympanic injection. We achieved an effective vertigo control of 59.4% and complete vertigo control rate of 53.1%. Worsening of symptoms was noted in 1 patient. Hearing was preserved in all patients except for one. Among the patients who attained effective vertigo control, 72.2% had dead labyrinth at 6-month cold caloric status. A single injection of 20 mg intratympanic gentamicin can alleviate intractable vertigo caused by definite Ménière's disease with hearing preservation. Non-responders may be given a second dose after one month. Intratympanic gentamicin is a simple, cheap treatment that can be carried out in an out-patient setting.

The Physiologic Role of Corticosteroids in Menière's Disease: An Update on Glucocorticoid-mediated Pathophysiology and Corticosteroid Inner Ear Distribution

: There are multiple treatment options for Ménière's disease (MD), including dietary modifications, aminoglycoside therapy, and surgery. All have limitations, ranging from limited effectiveness to permanent hearing loss. Corticosteroids have long been used to manage MD due to their relative efficacy and tolerability, but the exact mechanism for disease alleviation is uncertain. Until recently, the precise distribution and role that glucocorticoid receptors play in inner ear diseases have remained largely uninvestigated. Several studies propose they influence mechanisms of fluid regulation through ion and water homeostasis. This review will provide an update on the basic science literature describing the activity of endogenous glucocorticoids and exogenous corticosteroids in the inner ear and the relevance to MD, as well as early clinical trial data pertaining to the application of novel technologies for more effective administration of corticosteroids for the treatment of MD.

Menière's Disease and Caloric Stimulation: Some News from an Old Test

OBJECTIVES

The aim of the present study was to improve the instrumental diagnosis of assessing Menière's disease (MD) if the frequency and slow-phase velocity (SPV) of the thermally induced nystagmus analyzed through the caloric vestibular test (CVT) showed different alterations in relationship with an increasing severity of the cochlear involvement.

MATERIALS AND METHODS

The study retrospectively analyzed the CVT results of 72 patients affected by unilateral "definite MD" according to the 2015 Barany Society Diagnostic Criteria and treated only conservatively.

RESULTS

There were 7 (9.72%) patients in stage 1, 27 (37.50%) in stage 2, 35 (48.61%) in stage 3, and 3 (4.16%) in stage 4. The canal paresis (CP) calculated through the frequency of the thermally induced nystagmus on the affected side increased in more severe stages (p=0.033). Conversely, the CP calculated through the SPV was not significantly different among the stages showing abnormal values even in the early phases of the disease (71% in stage 1, 81% in stage 2, 91% in stage 3, and 100% in stage 4), exclusively on the affected side.

CONCLUSION

Abnormalities of the thermally induced nystagmus on the affected side characterize most patients with MD, but only "SPV" alterations are common in the early stages. An increasing severity of the cochlear involvement progressively reflects also on the "frequency" parameter. Detecting a dissociation between these two parameters could represent an instrumental marker of the early forms of MD. Cite this article as: Cerchiai N, Navari E, Miccoli M, Casani AP. Menière's Disease and Caloric Stimulation: Some News from an Old Test. J Int Adv Otol 2019; 15(3): 442-6.

Intratympanic gentamycine for Ménière's disease: is there a selective vestibulotoxic effect?

Purpose

The aim of our study is to investigate the effectiveness and safety of the treatment, based on vertigo diaries and pure tone audiograms.

Methods

The complete medical documentation of 105 definite patients suffering from Ménière’s disease was analyzed. In the studied group, nine patients were treated with intratympanic gentamycine. Long-term follow-up of the patients was carried out, using vertigo diaries, medical letters, anamnestic data, and pure tone audiograms. Audiometric results and vertigo complaints before and after treatment were contrasted using IBM SPSS V24 software.

Results

Based on our analysis, vertigo attacks appeared significantly less often after gentamycine treatment [p < 0.001; Odds ratio 0.003 (95% CI 0.001–0.012)], which confirms the efficacy of the therapy. Pure tone stages before and after the application of gentamycine were contrasted using the Mann–Whitney U test. When comparing the audiometric results of long-term follow-ups by using the logistic regression, a statistically significant difference was observed between the treated and not treated groups [p = 0.001; Odds ratio 0.141 (95% CI 0.064–0.313)], and based on the survivorship curve hearing impairment was more common in the not treated group which also supports our results. Based on the non-parametric test, there was no significant difference (p = 0.84) between the pure-tone stages of the control group and of those treated with gentamycine.

Conclusion

Our results indicate that intratympanic gentamycine is effective in controlling vertigo attacks, and there is no higher risk for hearing loss than in case of spontaneous progression of the disorder.

On-Demand and Low Dose Intratympanic Gentamicin for Meniere's Disease: A Customized Approach

OBJECTIVE

To evaluate the efficacy of on demand and low dose intratympanic gentamicin (ITG) in patients with intractable Meniere's disease (MD).

STUDY DESIGN

Clinical chart review.

SETTING

Secondary care center.

PATIENTS

Subjects with MD who failed conventional treatment and underwent on demand ITG infiltration from June 2013 to December 2018.

INTERVENTION

0.4 to 0.5 ml of buffered gentamicin were administered through an intratympanic route. A total of 5 mg in case of low dose and 20 mg as a standard dose.

MAIN OUTCOME MEASURES

Vertigo control, Meniere's Disease Functional Level Scale (MDFLS), Dizziness Handicap Inventory (DHI), and pure tone audiometry pre and posttreatment.

RESULTS

Thirty-one patients, 16 women and 15 men with a mean age of 52.81 (22-79) years were included. The number of ITG injections ranged from 1 to 7, with a mean of 2.52 applications per patient. Mean interval between doses was 212.15 (21-1442) days. Average follow-up was 24.03 months. An improvement on MDFLS was seen on 77.4% (n = 24) patients. DHI score improved after gentamicin treatment (mean 55.23 versus 24.06, p ≤ 0.001). Thirty patients (96.8%) reached complete or substantial vertigo control. Only one patient did not achieve control. Hearing was preserved in 43.5% (n = 10) of analyzed audiograms, whereas 17.4% (n = 4) developed hearing loss greater than 20 dB, which was not statistically significant (p = 0.099).

CONCLUSIONS

In our study, on demand and low dose ITG was effective for vertigo control in patients with intractable MD. Individualized therapy is recommended in all patients to minimize vestibular and cochlear toxicity.

A comparison of endolymphatic shunt surgery and intratympanic gentamicin for meniere's disease

OBJECTIVE

To report audiovestibular outcomes following endolymphatic shunt surgery (ELS) and intratympanic gentamicin injections (ITG) in patients with Meniere's disease (MD).

STUDY DESIGN

Retrospective matched cohort study METHODS: Patients with MD refractory to medical management between 2004 and 2017 were reviewed: 44 patients underwent ELS and had outcomes available, while 27 patients underwent ITG and had outcomes available. Mean follow-up durations for the ELS and ITG groups were 39.1 and 43.3 months, respectively. Twenty-six patients from the ELS group and 24 patients from the ITG group were then included in a pretreatment hearing- and age-matched analysis. Main outcome measures were successful control of vertigo, pure-tone average (PTA; 0.5, 1, 2 and 4 kHz), word recognition score (WRS), and treatment complications.

RESULTS

A matched analysis showed vertigo control rates of 73.1% in the ELS group and 66.8% in the ITG group, which were not significantly different (P = .760). The change in PTA following treatment was statistically similar between the ELS group (6.2 dB) and ITG group (4.6 dB) (P = .521), while the change in WRS for the ELS group (+3.9 %) was significantly more favorable than the ITG group (-13.6 %) (P = .046). Chronic post-treatment unsteadiness was reported in 25.0% of the ITG group and was not encountered in the ELS group (P = .009).

CONCLUSION

ELS provided successful vertigo control at least as well as ITG with a lower incidence of audiovestibular complications.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:2455-2460, 2020.

The Degeneration of the Vestibular Efferent Neurons After Intratympanic Gentamicin Administration

Intratympanic gentamicin (ITG) has been used to treat refractory Ménière's disease. Disequilibrium after ITG was still a challenge for some patients, and the underlying mechanism is poorly understood. Our previous study demonstrated that gentamicin distributed in the bilateral vestibular efferent neurons (VEN) after ITG; however, does it lead to VEN damage and cause further disequilibrium in patients following ITG? In this study, we observed severe damaged gentamicin-positive neurons of VEN and severe fractured myelin layer plates around neural fibers when viewed under transmission electron microscopy at day 3 after ITG. At day 30, neurons of VEN presented with relatively normal structures. Compared with the control group, the total number of choline acetyltransferase (CHAT) immunolabeling neurons in bilateral VEN showed a significant decrease both at day 3 and day 30. However, there was no significant difference in the total number of CHAT immunolabeling neurons between day 3 and day 30. It indicates that gentamicin is not only retrogradely transported into bilateral VEN, but also results in the degeneration of VEN after ITG. These findings may be related to patients' disequilibrium symptom after ITG. Furthermore, we speculate that VEN may play a role in vestibular compensation.

Partial Aminoglycoside Lesions in Vestibular Epithelia Reveal Broad Sensory Dysfunction Associated with Modest Hair Cell Loss and Afferent Calyx Retraction

Although the effects of aminoglycoside antibiotics on hair cells have been investigated for decades, their influences on the dendrites of primary afferent neurons have not been widely studied. This is undoubtedly due to the difficulty in disassociating pathology to dendritic processes from that resulting from loss of the presynaptic hair cell. This was overcome in the present investigation through development of a preparation using Chinchilla laniger that enabled direct perilymphatic infusion. Through this strategy we unmasked gentamicin's potential effects on afferent calyces. The pathophysiology of the vestibular neuroepithelia after post-administration durations of 0.5 through 6 months was assessed using single-neuron electrophysiology, immunohistochemistry, and confocal microscopy. Hair cell densities within cristae central zones (0.5-, 1-, 2-, and 6-months) and utricle peri- and extrastriola (6-months) regions were determined, and damage to calretinin-immunoreactive calyces was quantified. Gentamicin-induced hair cell loss exhibited a profile that reflected elimination of a most-sensitive group by 0.5-months post-administration (18.2%), followed by loss of a second group (20.6%) over the subsequent 5.5 months. The total hair cell loss with this gentamicin dose (approximately 38.8%) was less than the estimated fraction of type I hair cells in the chinchilla's crista central zone (approximately 60%), indicating that viable type I hair cells remained. Extensive lesions to afferent calyces were observed at 0.5-months, though stimulus-evoked modulation was intact at this post-administration time. Widespread compromise to calyx morphology and severe attenuation of stimulus-evoked afferent discharge modulation was found at 1 month post-administration, a condition that persisted in preparations examined through the 6-month post-administration interval. Spontaneous discharge was robust at all post-administration intervals. All calretinin-positive calyces had retracted at 2 and 6 months post-administration. We found no evidence of morphologic or physiologic recovery. These results indicate that gentamicin-induced partial lesions to vestibular epithelia include hair cell loss (ostensibly reflecting an apoptotic effect) that is far less extensive than the compromise to stimulus-evoked afferent discharge modulation and retraction of afferent calyces (reflecting non-apoptotic effects). Additionally, calyx retraction cannot be completely accounted for by loss of type I hair cells, supporting the possibility for direct action of gentamicin on the afferent dendrite.

Evaluation of the possible protective role of naringenin on gentamicin-induced ototoxicity: A preliminary study

OBJECTIVES

The purpose of this study is to evaluate the possible protective role of naringenin in gentamicin-induced ototoxicity through an audiological, biochemical and histopathological evaluation.

METHODS

This study was conducted on 32 adult male rats that were randomized into 4 groups(control, gentamicin, naringenin + gentamicin, and naringenin). Naringenin was given to the rats via oral gavage in a dose of 50 mg/kg/day during the 14 day study period. Gentamicin was given by the intraperitoneal route in a dose of 120 mg/kg/day. Audiological assessment was performed by the distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) measurements, applied to all rats at the beginning of the study, and also on day 14. Biochemical parameters were calculated on day 14 to evaluate the oxidative and antioxidative status. Their cochleae were removed and examined histopathologically, also on day 14. The cochlea of animals were evaluated with the terminal deoxynucleotidyl transferase-mediated dUTPbiotin nick end labeling (TUNEL) method for apoptosis.

RESULTS

On days 14, DPOAE values and ABR thresholds were preserved in group 3(naringenin + gentamicin) when compared with group 2(gentamicin)(p < 0.008). The total oxidant status values and oxidative stress index values were significantly higher in group 2(gentamicin) than in other groups (p < 0.008). The total antioxidant status value was significantly higher in group 3(naringenin + gentamicin) and group 4(naringenin) than in group 2(gentamicin)(p < 0.008). The number of TUNEL positive cells in both the organ of Corti and the stria vascularis were found to be statistically lower in group 3(naringenin + gentamicin) than in group 2(gentamicin)(p < 0.05).

CONCLUSION

Our study has demonstrated that the ototoxic effect generated by gentamicin could be ameliorated with the concurrent use of naringenin.

Repeated courses of intratympanic dexamethasone injection are effective for intractable Meniere's disease

CONCLUSION

Intra-tympanic dexamethasone injection (ITD) could serve as a first-line intra-tympanic (IT) treatment for Meniere's disease (MD), regardless of hearing level. Even if the response to initial ITD course was unsatisfactory, a repeated course may be beneficial with some patients.

OBJECTIVES

This study examined the effect of repeated courses of ITD administered on demand and investigated the possibility of ITD as an initial IT treatment for medically intractable MD patients.

METHOD

Fifty-one patients who had been diagnosed with definite MD and given course(s) of ITD treatment were included. Vertigo control, pure tone average and functional disability scores were evaluated against the American Academy of Otolaryngology-Head and Neck Surgery guidelines for MD.

RESULTS

Vertigo disappeared or was substantially controlled in 58.8% and 23.5% of the patients, respectively, after the first ITD course. A repeated course further raised the complete vertigo control rate by 15.7% and intra-tympanic gentamycin injection could be postponed or avoided in 78.6% of the patients who required repeated IT treatment. Hearing was unchanged after the first course of ITD (p > .05). No significant differences were detected in the clinical profiles or laboratory findings between patients receiving single course of ITD and those on multiple courses (p > .05).

Translabyrinthine vestibular neurectomy and simultaneous cochlear implant for Ménière's disease

BACKGROUND

Surgical management of Ménière's disease (MD) is recommended in case of medical and intratympanic treatment failures. Translabyrinthine vestibular nerve section has been considered the gold standard for denervation procedures in order to control vertigo attacks, although at the cost of sacrificing residual hearing. To the best of our knowledge, no work has been published with regard to a group of patients submitted to translabyrinthine vestibular neurectomy and simultaneous cochlear implant for MD. The aim of the present study was to assess the effectiveness of translabyrinthine vestibular nerve section and simultaneous cochlear implant in a prospective study.

METHODS

All adult patients (over 18 years of age) with a diagnosis of intractable unilateral definite MD and useless residual hearing function were enrolled after medical and intratympanic treatment failures. Pre- and postoperative otoneurological evaluation concerned: frequency of vertigo attacks, head impulse test and caloric testing, pure tone average and speech perception audiometry in quiet conditions, tinnitus handicap inventory test, functional level scale and rate of vertigo control, dizziness handicap inventory test, and MD patient-oriented severity index. At least 6 months of follow-up were needed to be enrolled in the study.

RESULTS

Four patients were included in the study. Translabyrinthine vestibular nerve section and simultaneous cochlear implant seemed to considerably improve the disabling effects of MD, achieving a good control of vestibular symptoms (mean pre/postoperative vertigo attacks per month: 16.5/0), resolving hearing loss (mean pre/postoperative pure tone average in the affected ear: 86.2/32.5 dB), improving the tinnitus (mean pre/postoperative tinnitus handicap inventory test: 77.2/6), and finally increasing the overall quality-of-life parameters.

CONCLUSIONS

In our preliminary report, translabyrinthine vestibular nerve section and simultaneous cochlear implant showed encouraging results in order to definitively control both vestibular and cochlear symptoms during the same therapeutic procedure.

Assessment of Vestibulo-oculomotor Reflex in Ménière's Disease: Defining an Instrumental Profile

OBJECTIVES

To analyze and compare, in two groups of patients affected by definite Ménière's disease (MD) but treated differently, the Video Head Impulse Test findings especially by putting them in relationship with canal paresis, hearing loss, and duration of the disease.

STUDY DESIGN

Retrospective chart review.

PATIENTS

Seventy patients affected by unilateral definite MD (16 in Group 1 and 54 in Group 2) observed between March 2014 and May 2015 in a tertiary referral center were retrospectively studied and then divided into two groups: Group 1 was previously treated with intratympanic gentamicin, whereas Group 2 underwent only a conservative therapy. Instrumental tests included audiometry, caloric test, and Video Head Impulse Test. All the findings were statistically analyzed; significance was set at p = 0.005.

INTERVENTION

Diagnostic.

MAIN OUTCOMES MEASURES

If MD is treated conservatively the high-frequency vestibulo-oculomotor reflex gain determined with Video Head Impulse Test is normal; it is pathological if MD is treated with gentamicin.

RESULTS

High-frequency vestibulo-oculomotor reflex gain showed a statistically significant reduction in Group 1; at the same time, it showed no correlation in both groups with hearing loss, duration of disease or canal paresis.

CONCLUSION

High-frequency vestibulo-oculomotor reflex is naturally preserved even in late stage MD if the patient has been treated conservatively; the dissociation between Caloric Test and Video Head Impulse Test findings could be considered an instrumental hallmark of MD. Gentamicin significantly reduces high-frequency vestibulo-oculomotor reflex gain: this reduction can be taken into account when determining the effectiveness of an ablative treatment.

It is 2015: What are the best diagnostic and treatment options for Ménière’s disease?

Ménière’s disease (MD) is a common cause of recurrent vertigo. Its pathophysiology is still unclear and controversial. The most common histological finding in postmortem temporal bone studies of patients is endolymphatic hydrops (EH). However, not all cases of hydrops are associated with MD and it may represent the end point of various etiologies. The diagnostic criteria for MD have undergone changes during the past few decades. A recent collaboration among specialty societies in United States, Europe and Japan has given rise to a new set of guidelines for the diagnosis and classification of MD. The aim is to develop international consensus criteria for MD that would help improve the quality of data collected from patients. The diagnosis of MD can be difficult in some cases as there is no gold standard for testing. Previous use of audiometric data and electrocochleography are poorly sensitive as screening tools. Recently magnetic resonance imaging as a diagnostic tool for identifying EH has gained popularity in Asia and Europe. Vestibular evoked myogenic potentials are also used but lack specificity. Finally, the treatment for MD has improved with the introduction of intratympanic treatments with steroids and gentamicin as well as less invasive treatment with the Meniett device.

Menière's disease

Menière's disease (MD) is a chronic multifactorial disorder of the inner ear characterized by episodic vestibular symptoms associated with sensorineural hearing loss, tinnitus, and aural pressure. Epidemiologic and genomic evidence supports a genetic susceptibility with multiple biochemical pathways involved, including the endocrine system, innate immune response, and autonomic nervous system. Allergens, infectious agents, vascular events, or genetic factors could modify inner-ear homeostasis and trigger MD. The diagnosis of MD is based on clinical criteria and requires the observation of an episodic vertigo syndrome associated with low- to medium-frequency sensorineural hearing loss and fluctuating aural symptoms (hearing loss, tinnitus, and/or fullness) in the affected ear. Headache is also found during the attacks and bilateral involvement is found in 25-40% of cases. Audiologic and vestibular assessment is recommended to monitor the clinical course. The treatment of MD is symptomatic to obtain relief of vestibular episodes and preventive to limit hearing loss progression. Treatment options include sodium restriction, betahistine, intratympanic gentamicin, or steroids and eventually surgery, such as cochlear implantation.

Surgery for vertigo: 10-year audit from a contemporary vertigo clinic

OBJECTIVE

To present the profile of patients undergoing surgical treatment for vertigo at a contemporary institutional vertigo clinic.

STUDY DESIGN

A retrospective analysis of clinical charts.

METHODS

The charts of 1060 patients, referred to an institutional vertigo clinic from January 2003 to December 2012, were studied. The clinical profile and long-term outcomes of patients who underwent surgery were analysed.

RESULTS

Of 1060 patients, 12 (1.13 per cent) were managed surgically. Of these, disease-modifying surgical procedures included perilymphatic fistula repair (n = 7) and microvascular decompression of the vestibular nerve (n = 1). Labyrinth destructive procedures included transmastoid labyrinthectomy (n = 2) and labyrinthectomy with vestibular nerve section (n = 1). One patient with vestibular schwannoma underwent both a disease-modifying and destructive procedure (translabyrinthine excision). All patients achieved excellent vertigo control, classified as per the American Academy of Otolaryngology - Head and Neck Surgery 1995 criteria.

CONCLUSION

With the advent of intratympanic treatments, surgical treatments for vertigo have become further limited. However, surgery with directed intent, in select patients, can give excellent results.

Quercetine attenuates the gentamicin-induced ototoxicity in a rat model

OBJECTIVES

The aim of this study is to evaluate the protective role of quercetin in gentamicin-induced ototoxicity through an auditory brainstem response (ABR) test and a histopathological evaluation of the cochlea.

METHODS

In this study, 48 female adult Sprague-Dawley rats aged 20-22 weeks and weighing 200-250g were used. An ABR test was carried out on all rats prior to drug administration, after which, the rats were divided into four groups of 12 animals each. Drug administration was gentamicin 120mg/kg plus ethanol in group one; gentamicin 120mg/kg plus quercetin 15mg/kg in group two; quercetin 15mg/kg in group three; and ethanol in group four. The drugs were administered intraperitoneally once a day for two weeks, and the ABR test was repeated after drug administration. Subsequently, the rats were sacrificed and their cochleae were dissected and examined histopathologically.

RESULTS

There was no significant difference between the pre-treatment ABR measurement values of the groups. However, a significant increase was detected in the ABR values in the group of rats that were administered gentamicin plus ethanol, while no statistically significant increase was found in the ABR values in the groups administered with gentamicin plus quercetin; quercetin alone; and ethanol alone. The number of TUNEL positive cells in the inner and outer hair cells in the Corti organ was found to be fewer, and Caspase 3 and 9 expressions were found to be weaker in the group receiving gentamicin plus quercetin than in the group receiving gentamicin plus ethanol.

CONCLUSIONS

Auditory function was detected to be significantly protected and apoptotic cells were found to be decreased when quercetin was administered together with gentamicin. From these results it was concluded that quercetin, a powerful antioxidant, attenuates ABR thresholds and histopathological lesions in the cochlea in gentamicin-induced ototoxicity in rats.

Single intratympanic gentamicin injection in Ménière's disease: VOR change and prognostic usefulness

OBJECTIVE

Assess angular vestibular-ocular reflex (VOR) changes after treatment with intratympanic gentamicin (ITG) for Ménière's disease (MD) and impact on short-term follow-up.

DESIGN

Prospective study.

METHODS

Patients submitted to ITG for unilateral MD. The gain VOR and the presence of compensatory saccades elicited by rapid head impulses were measured using the video head impulse test (vHIT).

RESULTS

The study included 31 subjects (mean age: 59 years). Functional Level Scale (FLS) distributions were 35,5% (FLS3); 32,2% (FLS4); and 32,2% (FLS5). Mean follow-up was 21 ± 7 months. Multiple injections were needed in nine patients. VOR gain in the treated ear was significantly reduced in all subjects and for all the semicircular canals (paired samples t test; P < 0,05). Gain averages after treatment were 0,61 (superior); 0,69 (horizontal); and 0,47 (posterior). A horizontal canal VOR gain superior to 0,80 after treatment was associated with the need for a second gentamicin injection (Chi-square; P = 0,003). Gain asymmetry between the symptomatic and asymptomatic ear (GASM) was increased after treatment. The rate of vestibular function reduction was 47,9%; 26,0%; and 35,8% for the superior, horizontal, and posterior canals, respectively. According to the receiving operator characteristic curve, the amount of change in GASM must be greater than 7 in order to predict the avoidance of a second procedure (area under the curve [AUC] horizontal canal = 0,861) and the amount of vestibular function reduction in the pathologic ear in patients with a controlled disease must be greater than 17,8% (AUC horizontal canal = 0,843).

CONCLUSIONS

When evaluated with the vHIT, intratympanic gentamicin changes in VOR seem to foresee short-term control of vertigo attacks.

LEVEL OF EVIDENCE

4.

Intratympanic Therapies for Menière's disease

There are multiple treatment options to consider when managing patients with Menière's disease. When conservative measures fail to control symptoms of Menière's disease, escalation of interventions may be required. Targeted drug delivery to the round window with intratympanic injections allows for local application of high concentrations of medications, largely avoiding systemic side effects. Intratympanic steroids have been shown to be effective at controlling vertigo symptoms, with less robust control rates than those seen with the use of intratympanic gentamicin. Dosing strategies have been modified over time to limit the potential for intratympanic gentamicin-induced ototoxicity. The introduction of intratympanic steroids coupled to a polymer designed for sustained round window drug application, may potentially afford improved duration of symptom control. This review evaluates the recent literature over the last year involving intratympanic therapies for Meniere's disease.