Dynamics in Endolymphatic Hydrops & Symptoms in Meniere's Disease After Endolymphatic Duct Blockage, Preliminary Results

Hydrops regression after vestibular denervation - longitudinal magnetic resonance study in patients with severe Meniere's disease treated with vestibular neurectomy

OBJECTIVES

The aim was to evaluate endolymphatic hydrops in patients with severe Ménière's disease (MD) before and after vestibular neurectomy to verify if vestibular denervation results in hydrops regression.

METHODS

Magnetic resonance imaging was performed after intravenous gadolinium injection in twenty patients with unilateral definite MD before and after the vestibular neurectomy. Clinical symptoms and audiovestibular tests were evaluated. Follow-up intervals ranged from 18 to 35 months after the surgery.

RESULTS

Endolymphatic hydrops were visualized in all patients in the preoperative scans. After the vestibular neurectomy, all patients presented a complete resolution of vertigo episodes. Regression of the endolymphatic hydrops was observed in 35% and 15% of cases analyzing cochlea and vestibule, respectively. In 71.43% of patients with utricular herniation into the lateral semicircular canal, withdrawal of the hernia was visualized. Asymmetrical contrast enhancement in the cochlea regressed in 17.64% of cases. Analyzing all the parameters collectively, in 60% of patients, partial regression of at least one of the radiological signs was confirmed in the follow-up examination. No progression of the endolymphatic hydrops was visualized after the surgery in either the cochlea or the vestibule.

CONCLUSIONS

Vestibular neurectomy is an effective treatment, eliminating vertigo attacks and improving the quality of life in patients with MD. Magnetic resonance imaging of the inner ear allows visualization of changes in endolymphatic hydrops degree after treatment. Regression of the endolymphatic hydrops after vestibular neurectomy suggests that vestibular denervation may effectively halt the progression of the endolymphatic space dilatation and result in hydrops regression.

Efficacy of endolymphatic duct blockage in treating Ménières disease

OBJECTIVES

Ménière's disease (MD) is an idiopathic inner ear disorder characterized by recurrent episodes of episodic rotational vertigo, fluctuating hearing loss, tinnitus, and a feeling of ear stuffiness. Endolymphatic sac (ES)-related surgery is used primarily in patients with MD who have failed to respond to pharmacologic therapy. Endolymphatic duct blockage (EDB) is a new procedure for the treatment of MD, and related clinical studies are still scarce. This study aims to investigate the dynamic changes in endolymphatic hydrops (EH) and the long-term surgical outcomes in MD patients undergoing EDB, and to evaluate the impact of different types of ES on the surgical efficacy.

METHODS

A retrospective analysis was conducted on 33 patients with refractory MD who underwent EDB. Based on the morphology of their endolymphatic sacs, patients were divided into a normal-type group (n=14) and an atrophic-type group (n=19). The frequency of vertigo symptoms, hearing, vestibular function, and the dynamic changes of gadolinium-enhanced MRI of the inner ear were compared were compared before and after surgery between the 2 groups.

RESULTS

Compared with the atrophic-type group, the patients in the normal-type group had a higher rate of complete vertigo control, better cochlear and vestibular function, and a lower endolymph to vestibule volume ratio (all P<0.05). In addition, 7 patients in the normal-type group were found to have reversal of EH, while no reversal of EH was detected in the atrophic-type group after surgery.

CONCLUSIONS

The response to EDB treatment varies between normal and atrophic MD patients, suggesting that the 2 pathological types of endolymphatic sacs may have different underlying mechanisms of disease.

Meniere's Disease Patients with Distinct Sac Pathoanatomic Findings React Differently to Endolymphatic Duct Blockage

OBJECTIVES

To explore the possible difference in response to endolymphatic duct blockage (EDB) treatment in patients with Meniere's disease (MD) with distinct pathoanatomic characteristics of the sac.

METHODS

In a total of 24 patients with MD receiving EDB treatment, the dynamics of the vertigo attack, hearing, vestibular function, and endolymph hydrops (EH) before surgery and 40 months following surgery in patients with normoplastic extraosseous portion of endolymphatic sac (eES) were compared with that in patients with atrophic eES.

RESULTS

A higher prevalence of complete vertigo control, better cochlear and vestibular function, and lower endolymph to vestibule-volume ratio were found in patients with normoplastic eES than in those with atrophic eES. Moreover, the reversal of EH was found in a total of six patients in normoplastic eES group, but no reversal of EH was detected in the atrophic eES group after surgery.

CONCLUSIONS

A difference in response to EDB treatment was shown in the MD patients with normoplastic eES and those with atrophic eES; the reversal of EH was found in the normoplastic eES group, but not in the atrophic eES group after surgery, suggesting two distinct pathologies in the eESs may underlie the pathogenesis of EH in two subgroups of MD patients.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:2761-2769, 2023.

Untargeted Metabolomic Analysis in Endolymphatic Sac Luminal Fluid from Patients with Meniere's Disease

Dysfunction of the endolymphatic sac (ES) is one of the etiologies of Meniere's disease (MD), the mechanism of which remains unclear. The aim of the present study was to explore the molecular pathological characteristics of ES during the development of MD. Metabolomic profiling of ES luminal fluid from patients with MD and patients with acoustic neuroma (AN) was performed. Diluted ES luminal fluid (ELF) samples were obtained from 10 patients who underwent endolymphatic duct blockage for the treatment of intractable MD and from 6 patients who underwent translabyrinthine surgery for AN. ELF analysis was performed using liquid chromatography-mass spectrometry before the raw data were normalized and subjected to subsequent statistical analysis by MetaboAnalyst. Using thresholds of P ≤ 0.05 and variable important in projection > 1, a total of 111 differential metabolites were screened in the ELF, including 52 metabolites in negative mode and 59 in positive mode. Furthermore, 15 differentially altered metabolites corresponding to 15 compound names were identified using a Student's t-test, including 7 significant increased metabolites and 8 significant decreased metabolites. Moreover, two differentially altered metabolites, hyaluronic acid (HA) and 4-hydroxynonenal (4-HNE), were validated to be upregulated in the epithelial lining of the ES, as well as in the subepithelial connective-tissue in patients with MD comparing with that in patients with AN. Among these differentially altered metabolites, an upregulated expression of HA detected in the ES lumen of the patients with MD was supposed to be associated with the increased endolymph in ES, while an increased level of 4-HNE found in the ELF of the patients with MD provided direct evidence to support that oxidative damage and inflammatory lesions underlie the mechanism of MD. Furthermore, citrate and ethylenediaminetetraacetic acid were detected to be decreased substantially in the ELF of the patients with MD, suggesting the elevated endolymphatic Ca2+ in the ears with chronic endolymphatic hydrops is likely to be associated with the reduction of these two chelators of Ca2+ in ES. The results in the present study indicate metabolomic analysis in the ELF of the patients with MD can potentially improve our understanding on the molecular pathophysiological mechanism in the ES during the development of MD.

Correlation of clinical parameters with endolymphatic hydrops on MRI in Meniere's disease

A clinical diagnosis of Ménière's disease (MD) is made based on medical history and audiometry findings. The 1995 American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) guidelines requires histopathological confirmation of endolymphatic hydrops (EH) for a diagnosis of “certain” MD. Symptoms such as dizziness and ear fullness are important diagnostic features; however, the descriptions provided by patients are frequently vague and non-specific. A recently developed magnetic resonance imaging (MRI) protocol to document EH is, therefore, useful for the evaluation of inner ear status in patients with MD. In this study, patients with MD were assessed using MRI and the HYDROPS (HYbriD of Reversed image Of Positive endolymph signal and native image of positive perilymph Signal) protocol to investigate the effectiveness of MRI for visualization of the endolymphatic space in the diagnosis of MD by correlating clinical laboratory parameters with the grade of EH. Of the 123 patients with MD recruited in this study, 80 had definite MD, 11 had probable MD, and 32 had possible MD based on the 1995 AAO-HNS guidelines. The EH grade based on HYDROPS MRI was determined independently by two otorhinolaryngologists and compared with several clinical parameters, including the diagnostic scale of MD (1995 AAO-HNS guidelines), pure tone average (PTA), low tone average (LTA), canal paresis (CP) on the caloric test, and disease duration. Cochlear hydrops and vestibular hydrops were detected in 58 and 80% of 80 definite MD ears, in 33 and 58% of 12 probable MD ears, and in 5 and 27% of 37 possible MD ears, respectively. The proportion of higher hydrops grades increased significantly with grade according to the MD diagnostic scale (p < 0.0001). Both PTA and LTA were significantly higher in patients with hydrops grade 2 than hydrops grade 0 in both the cochlea and the vestibule. CP was significantly higher in patients with grade 2 than grade 0 vestibular hydrops. Disease duration was not associated with hydrops grade. Radiological evaluation of MD using the HYDROPS protocol is useful for evaluation of the extent and severity of EH in the diagnosis of MD based on its pathophysiological mechanism.

Up-Regulated Expression of Interferon-Gamma, Interleukin-6 and Tumor Necrosis Factor-Alpha in the Endolymphatic Sac of Meniere's Disease Suggesting the Local Inflammatory Response Underlies the Mechanism of This Disease

Background

Immune mediated inflammatory changes affecting the endolymphatic sac (ES) may underlie the pathology of Meniere's disease (MD). The aim of the present study was to explore the differentially expressed cytokines in ES luminal fluid (ELF) of patients with MD, and the correlation between the expression of cytokines in the ELF with that in the serum was determined by quantitatively analyzing the cytokines in human ELF and serum.

Methods

Human ELF, serum and ES tissues were collected from patients with unilateral MD and patients with acoustic neuroma (AN) during surgery. The Simoa Cytokine 6-Plex Panel kit was used to analyze the levels of cytokines in the ELF and blood samples of the patients. Immunohistochemistry and immunofluorescence were subsequently used to validate the relative expression levels of the cytokines in MD.

Results

Significant differences were identified in the expression levels of interferon-γ (IFN-γ) (P < 0.001), interleukin (IL)-6 (P = 0.008) and tumor necrosis factor-α (TNF-α) (P = 0.036) in the luminal fluid of the ES comparing between the MD and AN groups. By contrast, the levels of IFN-γ, IL-10, IL-12p70, IL-17A, IL-6 and TNF-α in the serum of the MD group were not significantly different from those of either the AN group or healthy control subjects. In addition, no significant correlations in the expression levels of cytokines compared between the ELF and serum were found for the patients in either the MD or the AN group. Finally, the detection of positive expression of TNF-α, IL-6 and IFN-γ in the epithelial cells of the majority of ES specimens from patients with MD confirmed the up-regulated expression of these cytokines in the ES of patients with MD.

Conclusions

The identification of up-regulated expression levels of TNF-α, IL-6 and IFN-γ in the ELF in the present study has provided direct evidence for an increased immunologic activity in the microenvironment of the ES in patients with unilateral MD, may suggest the local inflammatory response underlies the mechanism of this disease.

A comparison of endolymphatic duct blockage, endolymphatic sac drainage and endolymphatic sac decompression surgery in reversing endolymphatic hydrops in Meniere's disease

Background

To explore the differences between endolymphatic duct blockage, endolymphatic sac drainage and endolymphatic sac decompression surgery in the reversal of endolymphatic hydrops (EH) in patients with intractable Meniere’s disease (MD).

Methods

A total of 27 MD patients receiving endolymphatic duct blockage surgery (n = 10), endolymphatic sac drainage surgery (n = 9) and endolymphatic sac decompression surgery (n = 8) underwent gadolinium-enhanced inner ear magnetic resonance imaging (MRI) scans prior to, 2 weeks after and at > 12 months following surgery.

Results

In the group with endolymphatic duct blockage, the second MRI revealed no changes in EH, whereas the third MRI revealed a reversal of vestibular EH in 3 patients and a downgrading of cochlear hydrops in 2 of these 3 patients, who presented with an improvement in their hearing and complete control of vertigo. In the group with endolymphatic sac drainage, the second MRI showed a reversal of EH in 4 patients, and no changes in EH in the remaining 5 patients, whereas the third MRI showed that those 4 patients who presented with a reversal of EH at the second MRI stage remained unchanged except a recurrence of vestibular hydrops in 1 patient. All 4 patients exhibited a complete control of vertigo, but hearing improved in 1, worsened in 1 and remained unchanged in 2. In the group with endolymphatic sac decompression, both the second and third MRI examination revealed no reversal of EH.

Conclusions

The present study has shown that both endolymphatic duct blockage surgery and endolymphatic sac drainage surgery have the potential to reduce EH in certain MD patients, but none of the patients receiving endolymphatic sac decompression surgery showed reversal of their EH.

Graphical Abstract