Intratympanic gentamicin in bilateral Menière's disease

Intratympanic Treatment in Menière's Disease, Efficacy of Aminoglycosides Versus Corticosteroids in Comparison Studies: A Systematic Review

OBJECTIVE

To compare the functional outcomes and complications of intratympanic gentamicin (ITG) versus intratympanic corticosteroids (ITC) in Menière's disease.

DATA SOURCES

An electronic search was conducted in the Cochrane Library, PubMed, and Embase databases on February 3, 2019. Articles written in English, Dutch, German, French, or Turkish language were included.

STUDY SELECTION

Study inclusion criteria were: 1) patients diagnosed with definite Menière's disease according to the criteria of the American Academy of Otolaryngology-Head and Neck Surgery, 2) treated with ITG or ITC in a comparison study, and 3) reported subjective and objective outcomes concerning Menière's disease.

DATA EXTRACTION

The quality of eligible studies was assessed according to an adjusted version of the Cochrane Risk of Bias tool. The extracted data were study characteristics (study design, publication year, and number of relevant patients), patient's characteristics (sex and age), disease characteristics (uni or bilateral and duration of Menière's disease), treatment protocol, and different therapeutic outcomes (vertigo, tinnitus, aural fullness, and hearing loss).

DATA SYNTHESIS

A total of eight articles were included for data extraction and analysis. For subjective outcomes, ITG was slightly favored compared to intratympanic corticosteroids. This was significant only in three studies (p < 0.05). For objective outcomes and complications, no significant differences were seen.

CONCLUSIONS

The result of this systematic review shows some benefit of ITG over ITC for subjective outcomes and no difference regarding objective outcomes or complication rate. However, this superiority of ITG is rather weak. Both interventions can be effectively and safely used in controlling Menière's disease in acute situations.

Fluctuating Sensorineural Hearing Loss

BACKGROUND

Several otologic conditions can present with fluctuating sensorineural hearing loss, including Ménière's disease, autoimmune inner ear disease, and enlarged vestibular aqueduct. Although these 3 etiologies vary greatly, distinguishing between these conditions at initial presentation can be challenging. Furthermore, initial treatment of these conditions is often similar. In this review, we discuss historical and current perspectives on diagnosis and treatment of these conditions.

SUMMARY

A literature search was performed regarding fluctuating hearing loss, and current treatment of these etiologies of fluctuating hearing loss was summarized. Immediate measures at the onset of acute hearing loss include corticosteroid therapy, while preventative and chronic therapies, which can limit disease severity and frequency, vary based on the specific condition treated. Key Messages: Fluctuating hearing loss can represent a range of pathologies, but the precise etiology may not be clear at initial presentation. Timely treatment and long-term follow-up, along with appropriate diagnostics, are necessary to optimize long-term hearing.

Surgical Management of Special Cases of Intractable Meniere's Disease: Unilateral Cases with Intact Canals and Bilateral Cases

If a clinician seeks to allow patients with vertigo to return to work as soon as possible, it is very important to determine the appearance of vestibular symptoms during convalescence just after treatment, as well as the long-term results. Apprehensive patients with vertigo may undergo severe psychological torment if treatment requires long-term rest in bed before they can return to daily life. In this paper, we observed postoperative vestibular symptoms (subjective sensation and objective nystagmus) in 50 patients with intractable Meniere's disease, including cases from our previous preliminary report, during the period of convalescence just after endolymphatic sac drainage and steroid instillation surgery (EDSS). All symptoms were eliminated within 8 days after EDSS. There was no significant difference in the duration of any vestibular symptoms between bilateral (n = 8) and unilateral cases (n = 42). This result indicates that EDSS could be as safe a treatment for bilateral Meniere's disease as for unilateral disease. In unilateral cases with intact semicircular canal function (n = 17), postoperative evoked vestibular sensation, positional, and positioning (Dix-Hallpike) nystagmus disappeared significantly earlier than in those with canal paresis (n = 25). This result indicates that EDSS could keep the vestibular peripheral function of patients with unilateral Meniere's disease with intact canals quite stable after surgery. Therefore, EDSS could be recommended as an initial, less-invasive surgical treatment for intractable Meniere's disease, especially in unilateral cases with intact canals and in bilateral cases.

What is Menière's disease? A contemporary re-evaluation of endolymphatic hydrops

Menière's disease is a chronic condition with a prevalence of 200-500 per 100,000 and characterized by episodic attacks of vertigo, fluctuating hearing loss, tinnitus, aural pressure and a progressive loss of audiovestibular functions. Over 150 years ago, Prosper Menière was the first to recognize the inner ear as the site of lesion for this clinical syndrome. Over 75 years ago, endolymphatic hydrops was discovered as the pathologic correlate of Menière's disease. However, this pathologic finding could be ascertained only in post-mortem histologic studies. Due to this diagnostic dilemma and the variable manifestation of the various audiovestibular symptoms, diagnostic classification systems based on clinical findings have been repeatedly modified and have not been uniformly used in scientific publications on Menière's disease. Furthermore, the higher level measures of impact on quality of life such as vitality and social participation have been neglected hitherto. Recent developments of high-resolution MR imaging of the inner ear have now enabled us to visualize in vivo endolymphatic hydrops in patients with suspected Menière's disease. In this review, we summarize the existing knowledge from temporal bone histologic studies and from the emerging evidence on imaging-based evaluation of patients with suspected Menière's disease. These indicate that endolymphatic hydrops is responsible not only for the full-blown clinical triad of simultaneous attacks of auditory and vestibular dysfunction, but also for other clinical presentations such as "vestibular" and "cochlear Menière's disease". As a consequence, we propose a new terminology which is based on symptomatic and imaging characteristics of these clinical entities to clarify and simplify their diagnostic classification.

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.

Factors Affecting Postural Instability in Ménière’s Disease

Objective

To assess the influence of factors that can affect the postural instability of Ménière’s disease (MD) patients.

Study Design

Case-control study.

Setting

Outpatient clinic in a university hospital.

Subjects and Methods

Fifty-four definite MD patients and 66 controls were included. Two-legged stance tasks were performed in 4 conditions: eyes open with and without foam rubber and eyes closed with and without foam rubber. We examined 6 variables: the velocity of movement of the center of pressure (COP), the envelopment area traced by the movement of the COP, Romberg’s ratio of velocity and area, and the foam ratios of velocity and area. For patients, stepwise multiple regression analyses were performed to explore the relationship between the 6 variables and the following independent variables: gender, age, the presence of abnormal caloric and/or cervical vestibular evoked myogenic potential (cVEMP) responses, the time elapsed since the last vertigo attack, and the disease duration.

Results

The presence of MD had a significantly positive relationship with all 6 of the variables ( P < .05). The presence of abnormal caloric and/or cVEMP responses had a significantly positive relationship with Romberg’s ratio of velocity ( P < .05) and area ( P < .01). The shorter time interval from last vertigo attack to measurement had a significantly positive relationship with the foam ratio of area ( P < .01).

Conclusion

MD patients show poor postural performance, which is affected by the existence of their peripheral vestibular function and the shorter time interval from last vertigo attack to measurement.

The effects of sound conditioning on gentamicin-induced vestibulocochlear toxicity in gerbils

OBJECTIVES/HYPOTHESIS

Recent studies in animal models have shown via physiologic and histologic measures that the administration of exogenous antioxidants is protective against gentamicin-induced oto-vestibulo toxicity. In addition, studies have also shown that sound conditioning increases cochlear antioxidants. The objective of this study is to determine whether sound conditioning provides protection against gentamicin in the cochlear and/or vestibular system.

STUDY DESIGN

: Prospective animal study.

METHODS

Three-month-old gerbils were divided into three groups (A, B, and C). The gerbils in group A were sound conditioned only (n = 2). In group B, the animals received gentamicin on the round window (n = 2). The gerbils in group C were sound conditioned first and later received gentamicin to the round window (n = 2). The animals were ultimately sacrificed and their right cochlea and posterior crista ampullaris were removed, processed, and sectioned. The specimens were analyzed for inner hair cell (IHC) and outer hair cell (OHC) loss and vestibular supporting and sensory hair cell nuclei per micrometer of vestibular epithelium.

RESULTS

The sound-conditioned group (A) had no loss of cochlear hair cells. The gerbils treated with gentamicin only (B) had a 34% decrease of OHCs and 49% decrease of IHCs. The sound-conditioned plus gentamicin-treated group (C) had a 5.5% decrease in OHCs and 12% decrease in IHCs. There were no significant differences with regards to supporting cell nuclei within the posterior crista across all groups. When compared to group A, the gerbils in groups B and C did have a 23 to 42% decrease in the number of sensory cell nuclei per micrometer of vestibular epithelium.

CONCLUSIONS

Sound conditioning does appear to attenuate the effects of gentamicin in the cochlea, although not significantly altering its vestibulotoxicity. An upregulation of cochlear-specific antioxidants is believed to be an important factor. As we had a small sample size, we can only note trends in the data, but future studies with more animals and measurements of antioxidant levels after sound conditioning would be useful to quantify this effect and determine if it can be exploited clinically. Laryngoscope, 2009.

Time course of repeated intratympanic gentamicin for Ménière's disease

OBJECTIVES/HYPOTHESIS

With low-dose and titration protocols, subsequent intratympanic (IT) gentamicin injections are frequently necessary for vertigo control in Ménière's disease. To date, studies have not provided detailed descriptions of the time course of recurrent vertigo and repeated injections. Our objective is to provide such a description with a Kaplan-Meier survival analysis, which may enable accurate predictions of the probability of recurrent vertigo after a given time or number of injections.

STUDY DESIGN

Injections of IT gentamicin were administered for unilateral definite Ménière's disease. One injection (or rarely more) in a 6-week period constituted a "round." Repeat rounds were given when needed for control of recurrent vertigo.

METHODS

We used a Kaplan-Meier method to quantify percentages of patients with control of vertigo over an 8-year period. A separate curve was created for each number of rounds, and failure for each was defined as the need for an additional round.

RESULTS

Of 78 patients, 75 (96%) achieved sufficient vertigo control to avoid ablative surgery, and 42 (54%) required only one round. Thirty-six (46%) required multiple rounds. The probability of needing another round increased with each subsequent one, through four rounds. The median times to the next round after one, two, or three rounds were 148, 118, and 124 days, respectively.

CONCLUSIONS

More than half of patients need only one round of IT gentamicin injections. With each additional round through the fourth one, the probability of additional rounds increases. Nevertheless, the majority (96%) of patients do not need ablative surgery after IT gentamicin.

Is surgical vestibular ablation necessary in disabling peripheral vertigo?

The use of intratympanic gentamicin is an easily performed office procedure for the conservative treatment of the Meniere's disease patient who has failed medical therapy. The procedure provides excellent control for the symptom of vertigo and is one of the most successful methods in the treatment of vertigo due to inner ear disorders. Surgical ablation is no longer necessary for adequate control of vestibular symptoms and that chemical ablation/alteration may replace the need for surgical vestibular ablation in cases of disabling Meniere's disease and other inner ear causes for peripheral vertigo.

Communication between the perilymphatic scalae and spiral ligament visualized by in vivo MRI

We evaluated the transport of Gadolinium-diethylenetriaminepentaacetate-bismethylamide (Gd-DTPA-BMA) through the round window (RW) membrane into the perilymphatic space with 4.7-T MRI in an animal study and 1.5-T MRI in humans. After administration of Gd-DTPA-BMA onto the intact RW membrane of guinea pig, Gd-DTPA-BMA uptake was observed in the basal turn and part of the second turn within 40 min. The scala tympani, scala vestibuli, the fibrous part of the spiral ligament and semicircular canal all showed uptake of Gd-DTPA-BMA. All turns of the cochlea were filled with Gd within 10 min in the perforated RW membrane administration group and within 30 min in the intravenous administration group. In patients who accepted middle ear injection of Gd-DTPA-BMA, uptake was observed within 2 h in the basal turn and semicircular canal. After 12 h the apex did still not show any uptake. Gd-DTPA-BMA is transported from the RW to the semicircular canal, the scala tympani and scala vestibuli without passing the helicotrema.

Intratympanic gentamicin for the treatment of Ménière's disease and other forms of peripheral vertigo

Titration therapy with intratympanic gentamicin offers class A or B control of vertigo in 87% (range, 75%-100%) of patients with unilateral Ménière's disease. The risk of additional hearing loss is about 21% (range,0-37%). Vertigo may recur, however, in nearly one third of patients over time. These recurrences can also be treated by intratympanic gentamicin with a similar risk of hearing loss. The salient effect of intratympanic gentamicin is probably the reduction of vestibular function through damage to hair cells, but a complete ablation of function does not seem to be necessary for vertigo control.

Middle ear instillation of gentamicin and streptomycin in chinchillas: electrophysiological appraisal of selective ototoxicity

The purpose of this study was to investigate selective vestibular ototoxicity of gentamicin and streptomycin in the chinchilla model. In total, 10 chinchillas underwent left middle ear instillation of one of three agents: gentamicin, streptomycin and saline. Electrophysiological data (otoacoustic emissions (OAEs), auditory brainstem evoked response (ABRs), and ice-water electronystagmography were recorded before and after instillation. Animals were sacrificed for temporal bone studies using scanning electron microscopy. Morphological changes in the cochlear and vestibular neuroepithelia were correlated with electrophysiological changes. Widespread ipsilateral cochlear and vestibular neuroepithelial injuries were observed and correlated with loss of OAEs, ABRs and ice-water caloric response. This study provides no evidence of selective vestibular ototoxicity of gentamicin or streptomycin. Morphological damage correlates with, but precedes loss of electrophysiological parameters. Chinchillas, like other small mammals, may not be an ideal model for the study of human ototoxicity.

Efficacy of increased gentamicin concentration for intratympanic injection therapy in Ménière's disease

OBJECTIVES

Update of ongoing case series of intratympanic gentamicin use in intractable Ménière's disease. Comparison of the treatment results of two gentamicin concentrations: 30 mg/ml and 40 mg/ml.

STUDY DESIGN

Retrospective case-matched review of an ongoing protocol.

SETTING

Ambulatory visits in an office setting.

PATIENTS

Eighty-seven patients were included in this study according to the 1995 guidelines of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) for reporting treatment results of Ménière's disease.

INTERVENTION

Intratympanic injection of a buffered gentamicin solution (30 mg/ml) was used in 44 patients (Group 1) in years 1992 to 1995. Stock gentamicin solution (40 mg/ml) was used in 43 patients (Group 2) in years 1996 to 1999. Treatment was titrated for each patient, and the hearing was strictly monitored. The endpoint of treatment was the complete cessation of vertigo spells.

MAIN OUTCOME MEASURES

Hearing results, vertigo control scores, and ice water caloric testing responses were analyzed after 24 months of follow-up. Thirty-two patients from each group were selected for case-matched statistical analysis.

RESULTS

Four or fewer gentamicin injections were used in 70% of Group 1 patients and 96% of Group 2 patients. In Group 1, vertigo control was achieved in 81% of patients, and the hearing remained the same or was improved in 68% of patients. In Group 2, vertigo control was achieved in 72% of patients, and the hearing remained the same or was improved in 81% of patients. Treatment was aborted in four patients of Group 2 for early reversible hearing loss, and 31 of 39 patients (79%) who completed the protocol experienced lasting vertigo control. There was a trend for longer-lasting vertigo control in the Group 2 patients.

CONCLUSION

It was concluded that increasing the gentamicin concentration to 40 mg/ml probably produces similar rates of vertigo control as those of the lower dose, at least initially, but requires fewer injections. The higher dose did not increase the risk of hearing loss if treatment was stopped at the first indication of injury. A larger study is needed to confirm the trend of improved long-term hearing results in patients treated with the 40 mg/ml solution.

Comparative cochlear toxicities of streptomycin, gentamicin, amikacin and netilmicin in guinea-pigs

All the aminoglycoside antibiotics now in clinical use are ototoxic. This study was designed to compare the toxic effects of four aminoglycoside antibiotics, streptomycin, gentamicin, amikacin and netilmicin, administered to guinea-pigs systemically (at respective doses of 125 mg/kg, 50 mg/kg, 150 mg/kg or 37.5 mg/kg, twice daily for 1 week) or topically via the transtympanic route (0.25 ml/kg in 4% saline, twice daily for 1 week). Chosen doses were 10-20 times higher than the recommended human dosage. Cochlear damage was observed in all animals that were given systemic and local aminoglycosides. The severity of the cochlear damage was in the order gentamicin, amikacin, streptomycin, netilmicin, with gentamicin being the most toxic. No statistically significant difference between the severity of cochlear damage resulting from the systemic and topical applications was detected.

Chemical and physical labyrinthectomy for Meniere's disease

The use of intratympanic gentamicin is currently a popular and easily performed office procedure for the conservative treatment of the Meniere's disease patient who has failed medical therapy or who is not a candidate for surgical therapy. The procedure provides excellent control for the symptom of vertigo. Despite this success, there remains a significant risk of hearing loss irrespective of administered dose. In the future, antioxidant [42,43] or salicylate therapy may prevent aminoglycoside toxicity [44]. These prophylaxis methods have shown promise in the laboratory. Current methods do not allow for accurate drug delivery to the inner ear. Middle ear mucosal status, round window thickness or adhesion, patency of eustachian tube, and the effect of endolymphatic hydrops on ototoxicity are factors simply out of the control of the operator's hands. Judging by the number of recent articles, intratympanic gentamicin instillation will continue to be an area of interest for the otologist. Users should be encouraged to be consistent and conservative in gentamicin dosing. It is clear that vestibular ablation is not necessary for adequate control of vestibular symptoms and that larger doses may increase the risk of hearing loss. American Academy of Otolaryngology-Head and Neck Surgery guidelines [45] should be used and adhered to for reporting on the treatment of Meniere's disease, so that the literature may be more comparable. In the same light, a prospective standardized trial would be helpful in determining ultimate efficacy and risk to the patient. Transmastoid labyrinthectomy remains the surgical standard for extirpating the offending labyrinth when hearing preservation is not an issue. In appropriate patients, the procedure is a safe and effective method for relieving patients of vertiginous attacks. Most patients tolerate the procedure very well and are able to compensate fairly well over the course of several weeks to months.

[Intra-tympanic gentamicin in the treatment of Ménière's disease: preliminary results ]

In the majority of patients suffering of Ménière's disease, medical treatment is sufficient to control symptoms, albeit, in a small number of them, the high intensity and frequency of vertigo spells makes necessary to adopt more aggressive measures, like intratympanic or general aminoglycoside administration, as well as surgical procedures. We present a prospective and longitudinal descriptive study with the results of intratympanic gentamycin in 24 patients labeled of Ménière's disease in the Otolaryngology Department of "Miguel Servet Hospital" in the last two years, after a follow-up period of more than a year, during which controlled medical treatment had been proved unsuccesfull. We go over the efficacy in terms of frequency of vertigo crisis, audition average, logoaudiometry and functional level. We obtained good results over vertigo control (types A and B of the objective criteria based in the improvement index after treatment) in 16 out of the 24 patients (66.6%), (13 were type A with total absence of crisis and 3 were type B) and an acceptable result (type C) in three of them (12.5.%). In the other five patients (20.83%) results were disappointing (types D and E) compelling to apply surgical treatment. We have tried to evaluate intratympanic gentamycin as an alternative treatment to more aggressive technics and we consider it to be a good option, with a low risk and scarce complications in the no pharmacologically controlled Ménière's disease patients.

Menière's disease: pathophysiology and treatment

Menière's disease is defined by the association of 4 symptoms: vertigo attacks, fluctuating hearing loss, tinnitus and an auricular plenitude sensation. The pathophysiology is commonly explained by a distension of membranous labyrinth by the endolymph, equally called endolymphatic hydrops. Recent studies also tend to relate the disease to immune mechanisms. The treatment is medical in the majority of patients but there is no international consensus on the management of the different stages of Menière's disease. Regarding the lack of clinical studies clearly demonstrating the effectiveness of a certain therapy or another. the recommendations are usually based on the empirical experience of practitioners and on the observation of a marked amelioration at 2 years of treatment in the majority of patients. The treatment of the acute phase of Menière's disease is basically symptomatic. Vestibular suppressant drugs have a well-established record in controlling acute attacks of vertigo. Most have variable anticholinergic, anti-emetic and vestibular sedative effects. If necessary, the administration of benzodiazepines will help to alleviate anxiety. Long term management of Menière's disease includes a low salt diet, the use of diuretics in the post-crisis phase, and the very common use in Europe of histaminergic agents. Corticosteroids are used in bilateral forms of Menière's disease, particularly if an autoimmune basis is suspected. All authors insist on the interest and the importance of regular follow-up, especially with regard to the psychological status and responsiveness to treatment of the patient. Surgical indications are rare and the least invasive procedures are used first. The choice of the procedure should take into consideration the need to preserve the auditory function of the patient.

Use of the round window microcatheter in the treatment of Meniere's disease

OBJECTIVES/HYPOTHESIS

Transtympanic gentamicin is an increasingly popular treatment for Meniere's disease. The present report examines the 2-year follow-up of our first 27 patients with Meniere's disease treated with the use of microdose gentamicin through the Round Window Microcatheter. We applied the 1995 American Academy of Otolaryngology-Head and Neck Surgery criteria to this patient group to analyze the results of treatment.

STUDY DESIGN

This study is an evaluation of consecutive patients with predetermined data collection on each patient.

METHODS

Patients with confirmed Meniere's disease underwent placement of the Round Window Microcatheter, which was filled with 10 mg/mL gentamicin, after placement into the round window niche was confirmed. Ten milligrams per milliliter of gentamicin was injected into the catheter by hand on two occasions after device placement in the first several patients. The remaining patients had continuous infusion of 10 mg/mL gentamicin at 1microL/h for the next 10 days. The catheter was removed 10 days after placement. All patients underwent an extensive set of hearing and vestibular tests on several occasions before, during, and after treatment.

RESULTS

In the patients in the study, vertigo was eliminated in 92.6%, with 3.7% of patients (1/27) demonstrating a mild permanent threshold shift in hearing. Tinnitus and pressure were significantly reduced in more than 65% of patients. Only one patient demonstrated a reduction of vestibular function after treatment.

CONCLUSIONS

Results of this study on this group of patients indicate that vertigo can be controlled in the long term using microdose gentamicin without a significant reduction in cochlear or vestibular function in most of the patients in our series. Our results are compared with the published literature examining transtympanic injection. In addition, the underlying science supporting this type of treatment is examined.

Microdose gentamicin administration via the round window microcatheter: results in patients with Meniere's disease

Transtympanic gentamicin is becoming increasingly popular in the treatment of Meniere's disease. In this report we examine our experience with the use of microdose gentamicin via the Round Window Microcatheter for the treatment of Meniere's disease. Thirty-six patients were treated with gentamicin administration via the Round Window Microcatheter between July 1997 and August 2000. The patients all underwent 10 days of continuous treatment with a total dose of 2.4-3.75 mg of gentamicin (10 mg/ml). All patients had extensive pre-, intra-, and post-therapy auditory and vestibular testing. In this group, vertigo was eliminated in 89% of the patients, and tinnitus and pressure were significantly reduced in over 60% of the patients. Only one patient suffered a significant hearing loss and, most importantly, in all but one patient vestibular function was improved or normalized after treatment. Round Window Microcatheter-administered microdose gentamicin is an exciting new treatment for Meniere's disease. Preliminary results indicate that vertigo can be controlled without a significant reduction in cochlear or vestibular function in most patients. These results suggest that this therapy may be acting at a non-hair cell site. Our results are compared to the published literature examining transtympanic injection. In addition, the underlying science supporting this type of treatment is examined.

Transtympanic versus sustained-release administration of gentamicin: kinetics, morphology, and function

OBJECTIVES/HYPOTHESIS

Transtympanic gentamicin therapy has become a popular treatment modality for Meniere's disease, but questions regarding the ideal dose of medicine, the best administration paradigm, and the safest treatment end-point remain unanswered. The goal of this study is to examine the inner ear kinetics of transtympanic gentamicin and compare this with the kinetics of sustained-release delivery in a basic science model. In addition, we plan to examine the relationship of these kinetics curves to the effect of the two treatment modalities on inner ear function and morphology. It is hoped that this analysis will help clinicians to better apply local medical therapy to the ear.

STUDY DESIGN

The study is a basic science project designed to examine perilymph gentamicin concentrations, hearing results, and inner ear morphology in an animal model.

METHODS

Gentamicin was applied to the right ear of chinchillas either through a transtympanic approach or in a sustained-release device. The left ear remained untreated as an internal control. At set time points the animals' hearing and balance function was studied and the perilymph was harvested, after which the animal was killed and preserved for histological evaluation. Kinetics curves were constructed for each of the two treatment paradigms and compared with histological and functional outcomes.

RESULTS

The two groups yielded dramatically different kinetics curves. The transtympanic curve had a high peak level at 24 hours with rapid fall-off and almost total elimination by 48 hours, whereas the sustained-release curve was characterized by a long, flat plateau phase with a peak that was approximately one-third that of the transtympanic curve. In addition, the variability seen in perilymph concentrations was significantly higher in the transtympanic group than in the sustained-release group. Immunohistochemical analysis using antibodies against cleaved caspase-3 and cleaved caspase-7 demonstrated early damage in the spiral ganglion of both groups, before any obvious morphological change in the hair cells. The staining was significantly more dense in animals with transtympanic delivery. Cochlear and vestibular hair cell damage was seen at late time points in animals from both groups. Hearing loss (HL) progressed in an orderly fashion in the sustained-release group of animals, with no HL seen in the early time points and universal significant threshold shifts present by 72 hours. In the transtympanic group, the HL was more variable, with significant threshold shifts occurring as early as 4 hours after treatment, but with some animals demonstrating preserved hearing at the 72-hour time point. All animals demonstrated profound HL at the 6-day time point.

CONCLUSIONS

There is a significant difference in the shape and variability of the perilymph kinetics curve when comparing sustained-release delivery to transtympanic delivery of gentamicin. High early peak levels of gentamicin seen with transtympanic therapy may have a profound effect on the spiral ganglion and produce early HL before obvious hair cell damage. Sustained delivery of gentamicin produces universal HL at 72 hours. The reliability of sustained-release delivery to the ear reduces functional and morphological variations between animals.

A review of medical treatment for Ménière's disease

A review of the literature on drug therapy for Ménière's disease was made using Medline to search for all publications between January 1978 and September 1998. A total of 152 publications were identified that specifically dealt with medical treatment for Ménière's disease. Only betahistine and diuretics appear to have proven efficacy in double-blind studies on the long-term control of vertigo. No treatment has a proven beneficial effect on hearing levels or on the long-term evolution of the disease. Recent publications have proposed a role for the intratympanic use of medication, mainly aminoglycosides, for control of vertigo. We conclude this review by proposing a strategy for the medical treatment of Ménière's disease.

Low-dose Oral Methotrexate Management of Patients with Bilateral Ménière's Disease

In this retrospective clinical trial, we evaluated the effectiveness of low-dose oral methotrexate in the management of bilateral Ménière's disease of immune-mediated origin. At our tertiary-care referral center, we evaluated ten men and eight women who had longstanding bilateral Ménière's disease that had been unresponsive to traditional conservative medical management. Sixteen of these patients had steroid-responsive bilateral Ménière's disease. Two patients had contraindications to steroids, but their clinical and laboratory evaluations were consistent with an immune-mediated process.

Patients were treated with 7.5 to 20 mg/week of oral methotrexate. The mean duration of treatment was 16.7 months (range: 8 to 35), with a mean followup of 2 years (range: 9 mo to 5 yr). Changes in clinical symptoms (vertigo, hearing loss, tinnitus, and aural fullness), audiometric changes, and side effects of therapy were evaluated.

Vertigo resolved in 14 patients (78%), was substantially alleviated in three patients (17%), and remained unchanged in one patient (6%). Hearing improved in five patients (28%) and stabilized in seven patients (39%). Tinnitus and aural fullness resolved or was relieved in 11 of 17 (65%) and 13 of 14 (93%) patients, respectively. Side effects were minimal and reversible.

We conclude that low-dose oral methotrexate is effective and safe for treating bilateral Ménierè's disease of immune-mediated origin. In this study, methotrexate alleviated vertiginous symptoms and improved or stabilized hearing in most patients. Low-dose methotrexate can be considered for patients with immune-mediated bilateral Meniérè's disease when long-term treatment is required or when a steroid or cyclophosphamide is contraindicated.

Intratympanic therapy for Ménière's disease. High-concentration gentamicin with round-window protection

Many therapeutic options exist for the management of patients with Ménière's disease. In the last few years, the use of intratympanic gentamicin has been investigated as an alternative treatment to vestibular nerve section or labyrinthectomy. In humans, the concentration of gentamicin used for intratympanic treatment of vertigo ranges from 10 mg/mL to 40 mg/mL, and the number of doses from 2 to 14, with a total administered amount between 6 and 2.400 mg. Here lower doses of gentamicin were used, usually had the lowest incidence of hearing loss, but more injections were needed to ablate vestibular function. The purpose of this study was to evaluate the acute and chronic ototoxic effects of intratympanic high-concentration gentamicin after having obliterated the round-window niche with connective tissue in 11 subjects' ears with Ménière's disease. Intratympanic gentamicin was administered according to a predetermined and fixed schedule consisting of two doses of 0.5 mL gentamicin solution, injected once a week with a drug concentration of 80 mg/mL. The total dose of gentamicin was < or = 80 mg. The charts of the patients were surveyed in accordance with the 1995 AAO-HNS guidelines. Three patients had recurrence of vertigo between 3 and 6 months after the second injection and went on to one additional dose of gentamicin. At 2 years follow-up, 10 patients (91%) had complete and 1 (9%) substantial control of vertigo; 3 subjects (27%) had hearing decreased. Tinnitus disappeared or decreased in 3 patients (27%); eight subjects (73%) reported their aural pressure abolished or decreased. The present study demonstrates that in patients with Ménière's disease, 0.5 mL gentamicin solution, with a concentration of 80 mg/mL (total dose < or = 80 mg), injected intratympanically once a week after having obliterated the round-window niche, permits complete or substantial control of vertigo in two-thirds of cases after two doses and in all subjects after three doses. This vertigo control rate is compared to that observed after vestibular nerve section. Hearing results are not different from those with natural control, with endolymphatic sac surgery, and with vestibular nerve section.

Headache in Meniere's disease

OBJECTIVE

We examined headache in 86 patients with severe or moderately severe Meniere's disease (MD) or with Meniere's syndrome (MS) chosen for intratympanic gentamicin treatment. Forty-five patients with vestibular neuronitis (VN) served as a control group.

METHODS

In addition to a clinical examination, the patients filled out a questionnaire concerning their headache.

RESULTS

Altogether 60 MD patients (70%) and 26 VN patients (58%) reported headache. Headache was severe in 35 MD patients (58%), moderate in 16 patients (27%) and slight in nine MD patients (15%), and as a whole more severe than that of the VN patients (P < 0.01). The MD patients exhibited significantly more occipital (P < 0.005) and neck headache (P < 0.005) than the VN patients. Analgesics had been used by 82%, antidepressants by 35%, sumatriptan by 13% and carbamazepine and/or amitriptyline by 12% of the MD patients suffering from headache. Pain relief was reported as good by 27%, satisfactory by 60%, poor by 5% of the MD patients and 8% could not rate the pain relief. In this study migraine was diagnosed in 5 MD patients.

CONCLUSION

It is concluded that MD is associated with headache that can be handicapping, and tricyclic antidepressants with pain alleviating medication is often needed to treat the headache in MD whereas sumatriptan did not alleviate the headache of the non-migraine patients.

Meniere's Syndrome

The primary goals of treatment in Meniere's syndrome are to control attacks of vertigo and, if possible, to arrest the progression of hearing loss. Initial treatment consists of rigid dietary sodium restriction, possibly with the addition of a thiazide diuretic. If disabling attacks of vertigo persist despite sodium restriction, surgical intervention should be considered. Endolymphatic shunting is an option for patients who desire a less invasive surgical remedy, but recurrence of vertigo occurs in about 40% of cases. Vestibular nerve ablative surgery is the definitive surgical treatment for patients with intractable attacks of vertigo who still have useful hearing on the affected side. Labyrinthectomy is a surgical option when there is no serviceable hearing in the damaged ear. Intra-aural gentamicin instillation is an option in carefully selected cases.

Intratympanic gentamicin in Meniere's disease

Ninety-three patients with intractable Meniere's disease were treated with gentamicin (Garamycin 40 mg/ml) administered in 1 to 4 transtympanic injections. The patients were tested at frequent intervals and followed up for 2 years. Before treatment all subjects experienced moderate or severe handicap caused by Meniere's disease. Two years after the treatment, rotatory vertigo was abolished in 81% of subjects, Tumarkin attacks were cured in 60%, and work capacity was severely reduced in 10% and moderately reduced in 17% of subjects. The outcome of the caloric responses did not correlate with the outcome of the treatment. In logistic regression analysis poor outcome of treatment correlated with Tumarkin attacks (odds ratio 5.5), severity of vertigo (odds ratio 3.8) and gait disorders (odds ratio 2.9). The mean hearing level was significantly affected by the treatment (before, 59.1 dB HL; after, 67.9 dB HL). Ten treated ears became deafened. During follow-up 44 subjects were subjected to retreatment, usually after 6 months. Intratympanic gentamicin treatment is a relatively safe and effective way to treat Meniere's disease. The authors recommended starting with 2 injections and renewing the injections if relapse occurs.

Intratympanic gentamicin treatment for Meniere's disease

OBJECTIVES

The purpose of this study was to evaluate the safety and efficacy of a modified intratympanic gentamicin technique in patients with intractable unilateral or bilateral Meniere's disease.

METHODS

A retrospective review of 25 consecutive patients who underwent gentamicin treatment for Meniere's disease was conducted between 1992 and 1996. Two separate delivery systems were used during this study, with the last 13 subjects undergoing placement of the new system (flanged polyethylene tubing).

RESULTS

Follow-up averaged 23 months. Absence of vertigo spells was reported in 88%, and substantial control was achieved in 12%. Four of five patients with bilateral disease achieved complete control. Results for the two delivery systems were not significantly different. Absence of ice-water caloric response was seen in 75% (15 of 20) patients. Clinically significant sensorineural hearing loss occurred in 5 (20%) of 25 ears. Nonserviceable hearing developed in only two (8%) patients.

CONCLUSIONS

Our results support the previously reported efficacy and relative safety of gentamicin infusion therapy for intractable Meniere's disease. Polyethylene tubing may be more advantageous than T-tube delivery because of anatomic concerns in certain patients.

Medical Management of Meniere's Disease

The management of Meniere's disease often creates a formidable clinical challenge. Drugs may be helpful in treating the acute attacks of vertigo, and in more long-term management. These remedies are largely symptomatic and there are few properly controlled studies of their efficacy. A critical overview of the scientific and clinical basis for these various pharmacological agents is discussed.

Transtympanic gentamicin in the treatment of Meniére's disease

Aminoglycosides enable a pharmacological approach, before resorting to surgery, to the treatment of Menière's disease (MD) proving unamenable to routine medical treatment. The staging of MD is an essential preliminary step in the implementation of a specific and personalized treatment with transtympanic gentamicin. The ideal condition is the presence of endolymphatic hydrops with little or no damage to the cochlear and vestibular hair cells. The technical aspects of the method are discussed. In 21 patients with unilateral Menière's disease in various stages, this treatment achieved the regression of vertigo in 86% of cases; hearing was better in 19% of cases, preserved in 62% and worse in 19%; tinnitus regressed totally or partially in 62% of cases; aural fullness also regressed totally or partially in 57% of cases.

Medical treatment of Menière's disease: a review of literature

A review of the literature on drug therapy for Menière's disease was made using the Medline on-line biomedical database to screen publications between January 1978 and April 1995. In total there were only 118 publications in this 17-year period which specifically dealt with medical therapy for Menière's disease. It appears that only betahistine and diuretics have a proven effect in double-blind studies on long-term control of vertigo in Menière's disease. No medical therapy, however, has a proven effect on hearing or long-term evolution of the disease. There are multiple reports, especially in the recent literature, regarding the intratympanal use of aminoglycosides for vertigo control. Based on this literature review and on empirical findings, a strategy for medical treatment of Menière's disease is proposed.

Intratympanic gentamicin for treatment of intractable Meniere's disease: a preliminary report

Topical administration of aminoglycoside antibiotics in the middle ear can achieve "chemical labyrinthectomy" in patients with intractable Meniere's disease. Herein we report our results of intratympanic gentamicin therapy in 21 patients using two different dosing protocols, twice weekly and twice daily (b.i.d.). Both hearing and vertigo outcome were evaluated. Complete control of episodic vertigo was achieved initially in 20 of 21 patients (95.2%). However, 6 of 20 responders (30%) developed relapsing symptoms within 12 months. Retreatment was successful in 75% of these patients. Overall, hearing was preserved or improved in 62% of cases, worse in 24%, and not yet tested in 14%. When the cumulative dose of gentamicin was < or = 4 injections in the first week, only 1 of 14 (7.1%) lost hearing. Intratympanic gentamicin offers better risk/benefit outcome than other invasive therapies for intractable Meniere's disease.

The pharmacological treatment of Menière's disease

The management of Menière's disease often provides a formidable clinical challenge largely because its precise aetiology is unknown. There is no known 'cure' once the condition is established, but drugs may be helpful in treating both the acute attacks of vertigo, and in more long-term management, particularly in the earlier fluctuant stage. These remedies are largely symptomatic and there are few if any properly controlled studies of their efficacy. Suppressant drugs may act centrally at neurotransmitter sites, or peripherally on the labyrinth. Conventional diuretics and osmotically acting agents have been given to reduce the endolymph fluid volume. Histamine analogues directly reduce inner ear fluid pressure mainly by increasing the cochlear blood flow, and are probably the treatment of choice. Otovestibulotoxic drugs given systemically to cause chemical labyrinthine ablation are frequently effective in abolishing attacks of vertigo but often resulted in disabling oscillopsia and ataxia. There is now evidence that local administration by intratympanic injection may well be more efficacious resulting in selective partial end organ ablation. To date innovative immune modifying regimes have not proved helpful.

Quantitative study of vestibulotoxicity induced by gentamicin or cisplatin in the guinea pig

Although aminoglycoside vestibulotoxicity is well established, the question of cisplatin vestibulotoxicity is controversial. The goals of this study were 1. to determine whether cisplatin induces vestibulotoxicity as measured histologically, and 2. to compare the vestibulotoxicity between gentamicin and cisplatin. Guinea pigs' vestibular end-organ hair bundles in control, gentamicin, and cisplatin groups were compared. In the lateral cristae of the cisplatin group, hair bundles decreased 21% on the central apex portion. In the gentamicin group, a slight decrease (17%) of hair bundles on the striola from the utricular maculae was observed, as was severe damage on the entire cristae, especially on the central apex (70%). These results indicate that gentamicin and cisplatin may not influence vestibular function of the otolithic membrane. However, gentamicin may severely damage and cisplatin may slightly damage the crista ampullaris hair bundles.

Effect of intratympanically administered gentamicin on hearing and tinnitus in Menière's disease

We have examined the effect of intratympanic gentamicin on hearing and tinnitus in 69 patients with intractable Menière's disease. Tinnitus was scored from 1 to 4 depending on its severity. The mean pure tone audiometry level before treatment was 57.5 dB and 1 year after treatment 63.5 dB Five subjects became deaf in the treated ear, and in 13 subjects hearing loss was > 10 dB and in 21 subjects 0 10 dB. In 25 subjects significant improvement (> 10 dB) was gained, and in 5 patients. Tinnitus was significantly reduced after treatment with gentamicin. A total of 66 patients had tinnitus before treatment and tinnitus relief was rated as good. Four percent of the subjects had no tinnitus, 30% had slight tinnitus. 27% moderate tinnitus. 18% severe and 8% handicapping tinnitus.