Long-term efficacy of triple semicircular canal plugging in the treatment of patients with ipsilateral delayed endolymphatic hydrops.

This study aims to explore the long-term efficacy of triple semicircular canal plugging (TSCP) in the treatment of intractable ipsilateral delayed endolymphatic hydrops (DEH), so as to provide an alternative therapy for this disease. Forty-eight patients diagnosed with ipsilateral DEH referred to vertigo clinic of our hospital between Dec. 2010 and Dec. 2017, were included in this study for retrospective analysis. All patients were followed up for 2 years. Vertigo control and auditory functions were measured and analyzed. Pure tone audiometry, caloric test, and vestibular evoked myogenic potential (VEMP) were performed in two-year follow-up. Forty-five patients who accepted intratympanic gentamicin (26.7 mg/mL) twice given one week apart were selected as a control group. The total control rate of vertigo in TSCP group was 97.9% (47/48) in the two-year follow-up, with complete control rate of 83.3% (40/48) and substantial control rate of 14.6% (7/48). The rate of hearing loss was 22.9% (11/48). The total control rate of vertigo in intratympanic gentamicin group was 80.0% (36/45), with complete control rate of 57.8% (26/45) and substantial control rate of 22.2% (10/45), and the rate of hearing loss was 20.0% (9/45). The vertigo control rate of TSCP was significantly higher than that of intratympanic gentamicin (χ2 = 6.01, p < 0.05). There was no significant difference of hearing loss rate between two groups. (χ2 = 0.12, p > 0.05). TSCP, which can reduce vertiginous symptoms in patients with intractable ipsilateral DEH, represents an effective therapy for this disorder.

Furosemide-loading vestibular evoked myogenic potential testing can suggest developing bilateral involvement of unilateral Meniere's disease.

CONCLUSIONS: Patients with positive results of furosemide-loading vestibular evoked myogenic potential (F-VEMP) testing in the unaffected ears of unilateral Meniere's disease have a high incidence of developing bilateral lesions. OBJECTIVE: To clarify the meaning of positive results of F-VEMP testing of the unaffected ear of patients with unilateral Meniere's disease. METHODS: Twenty-five patients with unilateral Meniere's disease were investigated in this study. The positive group consisted of 6 patients with positive results of F-VEMP testing in the contralateral ear and the negative group consisted of 19 patients with negative results. The incidence of contralateral involvement was compared in both groups by the Kaplan-Meier method. RESULTS: Contralateral involvement was seen in three cases (50%) in the positive group after 2, 12, and 26 months and in three cases (16%) in the negative group after 27, 56, and 78 months. The positive group had a higher incidence of contralateral involvement than the negative group (p = 0.0017, according to a log-rank test).

Decompression effects of erythritol on endolymphatic hydrops.

OBJECTIVE: The effect of the uptake of erythritol with and without the addition of pectin on fecal condition, p-OSM and p-AVP levels, and the endolymphatic volume was investigated to consider the possibility that erythritol is applicable as a therapeutic agent for Meniere's disease. MATERIALS AND METHODS: Two experiments were performed using 100 female Hartley guinea pigs. Experiment 1 was designed to morphologically investigate the influence of the uptake of erythritol with or without the addition of pectin on the endolymphatic volume. Experiment 2 was designed to investigate changes in p-OSM and p-AVP levels after the uptake of erythritol with or without the addition of pectin. RESULTS: (1) Endolymphatic hydrops significantly decreased after the uptake of a mixture of erythritol and pectin, but did not decrease after the uptake of pectin or erythritol (p<0.001). (2) The fecal condition was muddy in all animals with the uptake of erythritol alone, but muddy or very soft feces were not observed in animals with a mixture of pectin and erythritol. p-AVP and p-OSM levels were significantly elevated in animals with the uptake of erythritol alone or a mixture of erythritol and pectin. Notably, the increase in p-AVP and p-OSM levels was significantly more evident in animals with the uptake of erythritol alone (one-way ANOVA, p<0.001). CONCLUSIONS: The addition of pectin almost completely suppressed erythritol-induced diarrhea. Consequently, the secondary elevation of p-AVP and p-OSM due to diarrhea was also reduced. The uptake of a mixture of erythritol and pectin markedly decompressed endolymphatic hydrops, although the uptake of erythritol alone did not. The difference of the decompression effect between animal groups with the uptake of erythritol alone and a mixture of erythritol and pectin seemed to be attributable to the difference of p-AVP levels due to diarrheal state.

Evaluation of the effect of dexamethasone in experimentally induced endolymphatic hydrops in guinea pigs.

PURPOSE: The aim of this study was to investigate the audiological and histopathologic effects of dexamethasone in the treatment of experimentally induced endolymphatic hydrops. MATERIALS AND METHODS: Thirty mature, male guinea pigs weighing 400 +/- 50 g were operated on to induce experimental endolymphatic hydrops in their right ear. Left ear served as control. Subjects were separated into control and dexamethasone groups, with the latter receiving dexamethasone 5 mg/(kg d) intraperitoneally for 10 days. Electrocochleography and auditory brainstem response were applied to all subjects at preoperation, on the second postoperative day and also on the 15th postoperative day in animals that lived for a long time. The histopathologic examination of the inner ear in all animals was done at the end of the study. RESULTS: The summating potential and the ratio of the summating potential to the action potential measured on the second postoperative day were found to be increased in both groups, but more significantly in the control one. When the left and right ears were compared, significant difference was found in the control group; however, no significant difference was found between the ears in the dexamethasone group. Histopathologic examination revealed varying degrees of hydrops in the control group, but showed only normal findings or minor changes in the dexamethasone group. CONCLUSIONS: Dexamethasone can prevent the audiological and histopathologic findings of experimentally induced endolymphatic hydrops. However, these results must be supported by clinical and experimental studies designed with a large number of subjects.

Frequency dynamics shift of vestibular evoked myogenic potentials in patients with endolymphatic hydrops.

OBJECTIVE: To measure the frequency dynamics of the vestibular evoked myogenic potential in patients with endolymphatic hydrops. STUDY DESIGN: A prospective study. SETTING: A university hospital. SUBJECTS: The endolymphatic hydrops group consisted of 28 affected ears of patients with definite unilateral Ménière's disease and a control group of 36 ears of 20 healthy volunteers. INTERVENTIONS: Vestibular evoked myogenic potentials generated by tone bursts at 250, 500, 700, 1,000, 1,500, 2,000, and 4,000 Hz were measured in both groups. Vestibular evoked myogenic potentials were also measured after furosemide administration in six patients in the endolymphatic hydrops group. MAIN OUTCOME MEASURE: The frequency sensitivity of vestibular evoked myogenic potential, as evaluated by p13-n23 normalized amplitude. RESULTS: Peak amplitudes were noted at 500 Hz in the control group and at 1,000 Hz in the endolymphatic hydrops group. After furosemide loading, peak amplitude shifted to a lower frequency in four of six ears. CONCLUSION: The peak amplitude of vestibular evoked myogenic potentials in the endolymphatic hydrops group was at a higher frequency than in the control group. The frequency of the saccule (nu) should be proportional to radical(tau/sigma), where tau is the tension of membrane and sigma is its density. We advocate the hypothesis that the shift in frequency dynamics of vestibular evoked myogenic potential in patients with endolymphatic hydrops originates from the morphologic features of the saccule, analogous to an expanded balloon.

Effect of isosorbide on distortion-product otoacoustic emissions and endocochlear DC potential in experimentally induced hydropic ears.

The effects of isosorbide on distortion-product otoacoustic emissions (DPOAEs) and endocochlear DC potential (EP) were examined in experimentally induced endolymphatic hydropic ears and untreated control ears using 20 albino guinea pigs. DPOAEs and EP in the hydropic ears decreased after obliteration of the endolymphatic duct and sac. The administration of isosorbide restored DPOAEs to the normal level, whereas EP was further reduced. In control ears there was no significant change in DPOAEs and EP after the administration of isosorbide. The results obtained in the present study indicate that the effect of isosorbide on DPOAEs is different from that on EP, and the recovery of DPOAEs in hydropic ears is not a secondary phenomenon due to the recovery of EP.

Immediate and long-term effects of daily glycerol administration on guinea pig hydropic ears.

Oral administration of glycerol at 0.5 g/kg and 1.0 g/kg body weight in the guinea pig with experimentally induced hydrops provoked no obvious modifications of the CAP audiogram within a 3-h recording session. Daily administration of glycerol at the same dose level during a 4-month period did not modify the deterioration of CAP thresholds although some limited beneficial effect was detected for some animals after 8 weeks of treatment.