Evidence Of Endolymphatic Hydrops Research Articles

Comparison between 3D-FLAIR and 3D-real IR MRI sequences with visual classification method in the imaging of endolymphatic hydrops in Meniere's disease

BackgroundClinically, the evidence of endolymphatic hydrops (EH) in Meniere's disease (MD) primarily relies on audiological examinations, such as glycerol tests and electrocochleography, to suggest the presence of EH indirectly. However, these techniques lack sensitivity and specificity, and they do not sufficiently assess the degree of EH. This study aims to explore the application of three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) and three-dimensional real inversion recovery (3D-real IR) sequence imaging of EH in MD and to assess the image quality and grading of EH. MethodsThe study included 50 patients with definite MD. The 3D-FLAIR and 3D-real IR sequence images were performed 24 h after bilateral intratympanic injection of gadolinium. The image quality of both sequences was reviewed by two experienced radiologists. The vestibular and cochlear EH grades of both sequences were reviewed by two experienced otologists using a visual grading method. The Cohen's kappa and Pearson tests were used to analyze the data. ResultsThe reliability of image quality between the two radiologists was excellent (0.7 < kappa < 0.9). There were significant statistical differences in the image quality between the 3D-real IR and 3D-FLAIR sequences (p = 0.023 and p = 0.035, respectively). The reliability for the grading of vestibular and cochlear EH between the two otologists was excellent (0.7 < kappa < 0.9). The 3D-real IR sequence detected more severe hydrops than did the 3D-FLAIR sequence (p < 05). ConclusionThe image quality of the 3D-real IR sequence is better than that of the 3D-FLAIR sequence, and there are differences in the vestibular and cochlear EH grades of both sequences. The sensitivity of the 3D-real IR sequence in the cochlea is higher. The method of visual grading can be applied to both technologies when combined with 3D-real IR.

How Often Does Stapedectomy for Otosclerosis Result in Endolymphatic Hydrops?

1) To evaluate the long-term (≥10 year) clinical incidence of endolymphatic hydrops (EH) after stapedectomy for otosclerosis, using low-frequency sensorineural hearing loss (LFSNHL) as a marker for EH. 2) To determine the histologic incidence of EH in human temporal bone specimens (TBS) with a history of stapedectomy for otosclerosis. 3) To determine the histologic incidence of EH in a control group of human TBS. Retrospective review and temporal bone study. Tertiary medical center and temporal bone pathology laboratory. Patients with otosclerosis, human TBS with otosclerosis, and human TBS with presbycusis as the control group. Pure-tone audiometry, temporal bone pathology. 1) LFSNHL, defined as >10 decibel elevation of bone conduction thresholds at 250 and 500 Hz, after correcting for age-related hearing loss (per ISO 7029). 2) Histologic assessment of EH. In patients with otosclerosis, 8 of 110 (7.3%) operated patients versus 3 of 123 (2.4%) nonoperated patients developed LFSNHL (p = 0.08). No patients with LFSNHL had other symptoms of EH. In TBS with otosclerosis, 11 of 93 (11.8%) operated TBS versus 3 of 156 (1.9%) nonoperated TBS had evidence of EH (p <0.001). In the control group of TBS with presbycusis, 9 of 253 (3.5%) had EH. The long-term incidence of LFSNHL, a marker for EH, in patients with otosclerosis was not significantly higher in those who underwent stapedectomy. The histologic incidence of EH, however, was significantly higher in TBS that had undergone stapedectomy compared with nonoperated TBS or a control group of TBS.

Preceding profound deafness and co-factors promote development of endolymphatic hydrops in preliminary patients with delayed endolymphatic hydrops

Conclusion: Profound deafness (PD) is unlikely to be the only cause of endolymphatic hydrops (EH) in patients with delayed endolymphatic hydrops (DEH). Further studies in large patient cohorts are required to determine the etiologic co-factors involved in the development of EH in patients with PD and DEH.Objectives: DEH usually occurs in patients with sustained unilateral PD who then develop episodic vertigo or fluctuating hearing loss. The latency can vary markedly between PD and development of DEH, but the factors affecting inner ear homeostasis and causing EH during this latency period remain unclear. The study aimed to assess the differences in EH and functional status of the inner ear between patients with PD only and those with DEH.Method: Two PD and 10 DEH patients who had developed PD in early childhood were enrolled. Gadolinium-enhanced magnetic resonance imaging of the inner ear was performed in all patients to assess the degree of EH in the vestibule and cochlea.Results: There was no evidence of EH in the affected ears of patients with PD alone. DEH patients, however, showed significant EH in either the cochlea or vestibule, suggesting that EH development and DEH onset were strongly correlated.

Vasopressin in definite Meniere's disease with positive electrocochleographic findings

Conclusion: There was no evidence of a mean raised vasopressin level in 80 subjects suffering from definite Meniere's disease with positive electrocochleographic findings. There was no correlation with stress. The only group with a mildly raised level comprised those who had had a vertigo attack within a day. The most likely cause is nausea, which is the most potent trigger for vasopressin release. Objective: It has been claimed that patients with Meniere's disease have raised vasopressin levels. This has been linked with a long-standing notion that that there is a link between stress and Meniere's disease, so that an increase in vasopressin could trigger a vertigo attack. Methods: Serum vasopressin concentrations were measured in 80 patients with Meniere's disease whose diagnosis was based on conventional symptom criteria plus electrocochleographic evidence of endolymphatic hydrops. Results: The community mean for vasopressin is 2.2 pmol/L (SD = 2.4). For all 80 Meniere's patients the mean vasopressin concentration was 2.1 pmol/L (SD = 1.6), and 2.8 pmol/L (SD = 0.9) when the last attack was within a day.

Surgical Induction of Endolymphatic Hydrops by Obliteration of the Endolymphatic Duct

Surgical induction of endolymphatic hydrops (ELH) in the guinea pig by obliteration and obstruction of the endolymphatic duct is a well-accepted animal model of the condition and an important correlate for human Meniere's disease. In 1965, Robert Kimura and Harold Schuknecht first described an intradural approach for obstruction of the endolymphatic duct (Kimura 1965). Although effective, this technique, which requires penetration of the brain's protective covering, incurred an undesirable level of morbidity and mortality in the animal subjects. Consequently, Andrews and Bohmer developed an extradural approach, which predictably produces fewer of the complications associated with central nervous system (CNS) penetration.(Andrews and Bohmer 1989) The extradural approach described here first requires a midline incision in the region of the occiput to expose the underlying muscular layer. We operate only on the right side. After appropriate retraction of the overlying tissue, a horizontal incision is made into the musculature of the right occiput to expose the right temporo-occipital suture line. The bone immediately inferio-lateral the suture line (Fig 1) is then drilled with an otologic drill until the sigmoid sinus becomes visible. Medial retraction of the sigmoid sinus reveals the operculum of the endolymphatic duct, which houses the endolymphatic sac. Drilling medial to the operculum into the area of the endolymphatic sac reveals the endolymphatic duct, which is then packed with bone wax to produce obstruction and ultimately ELH. In the following weeks, the animal will demonstrate the progressive, fluctuating hearing loss and histologic evidence of ELH.

Meniere's disease: the incidence of hydrops in the contralateral asymptomatic ear.

This study analyzes the incidence of endolymphatic hydrops in the asymptomatic contralateral ear of patients with classic Meniere's disease. A retrospective study of 3000 subjects who underwent electrocochleography (ECOG) from 1988 to 1998. The presence of endolymphatic hydrops was determined by use of ECOG recordings, which were made through a transtympanic recording needle situated in the round window niche. Analysis was made of the 1-kHz toneburst summation potential (SP), and comparison was made between asymptomatic contralateral "Meniere's ears" (n = 144) and asymptomatic normal "control ears" (n = 114). Results demonstrated that more than 10% of the contralateral asymptomatic Meniere's ears have an ECOG recording that is highly suggestive of the presence of endolymphatic hydrops. In contrast, less than 2% of the control population demonstrate abnormal ECOG recordings. Furthermore, 15% of the population of contralateral Meniere's ears lie above the 95th percentile of the control population for 1-kHz tone-burst (100 dB) SP negativity. This study suggests that a high percentage of patients who have what appears to be unilateral Meniere's disease have evidence of endolymphatic hydrops in the contralateral asymptomatic ear. This finding has important clinical relevance for the management of patients in whom destructive surgery is planned and further highlights the importance of electrocochleography in the diagnosis and management of this disease process.

Endolymphatic Mastoid Shunt Surgery in Unilateral Meniere's Disease

One-hundred endolymphatic mastoid shunt operations in patients with classic unilateral Meniere's disease were analyzed. The patients were carefully preselected with a comprehensive protocol of audiovestibular and metabolic investigations. All patients had definitive electrophysiologic evidence of endolymphatic hydrops with an enhanced negative summating potential on transtympanic electrocochleography. The surgical results were analyzed both by the original American Academy of Ophthalmology and Otolaryngology Guidelines (AAOO, 1972), and the more recent modifications of the American Academy of Otolaryngology-Head and Neck Surgery (AA-HNS, 1985). Control of vertigo was achieved in 79% of the patients overall, with 42% sustaining complete control and 37% substantial control. A significant hearing improvement was obtained in 15% of cases, there was no change in 56% of patients, and hearing became worse in 29%. Tinnitus improved following surgery in 35% of patients, was the same in 56%, and worse in 9%. Postoperatively, there was no disability in 42% of the patients, some degree of disability in 50%, and severe disability and inability to sustain gainful employment in only 8%.

Investigation of the physiological basis of summating potential changes in endolymphatic hydrops.

An increase in the ratio of the summating potential to the action potential components of the electrocochleogram is known to be a feature of endolymphatic hydrops. We investigated the value of the SP/AP ratio in response to condensation and rarefaction click stimuli delivered separately. In patients with electrophysiological evidence of endolymphatic hydrops there was found to be a significantly greater SP/AP ratio to condensation clicks than rarefaction clicks. This finding supports the hypothesis that the increased SP/AP ratio in hydrops is due to mechanical asymmetry of the basilar membrane.

Pathology of Méniére's disease. Further studies.

Temporal bone findings are described in a 66-year-old white man with a one and one-half year history of Meniere's syndrome. Unilateral advanced endolymphatic hydrops of the cochlea and saccule, and numerous outpouchings of the utricle and semicircular ampullae were present. There was displacement of the utricle into the perilymphatic space of all the ampullae, as well as retrograde endolymphatic hydrops of most of the crus commune. The endolymphatic duct and intermediate portion of the endolymphatic sac demonstrated a rather straight course to the posterior fossa, with virtually no lateral curving. This same finding, however, was present in the opposite side where there was no evidence of endolymphatic hydrops. The cochlea, on the involved side, demonstrated considerable decrease in spiral ganglion cells and outer and inner hair cells throughout, most severe in the beginning of the basal turn. Degenerative changes were present in all the vestibular sensory receptor areas. Incidental histological otosclerosis of the oval window was found bilaterally. An unusual finding was bilateral focal nodular hyperplasia of the Schwann cells of the facial nerve within the internal auditory canal, with no compression of adjacent nerve trunks. This condition is rare and may simulate true tumors. The etiology here was unassociated with any other neurological disorder and is unexplained.