Relationship Between Cochlear Lateral Wall Changes and Endolymphatic Hydrops in Otitis Media.

OBJECTIVES: Despite otitis media and various disease processes being associated with endolymphatic hydrops (EH), an exact explanation of the pathophysiology has yet to be reported. This study aimed to investigate the changes in the cochlear lateral wall structures and their potential correlation with the presence and severity of cochlear EH in acute and chronic otitis media cases. The investigations were conducted in both chinchilla animal model and human temporal bone specimens. METHODS: We studied a total of 15 chinchilla and 25 human temporal bones from our collection, which were categorized into acute otitis media, chronic otitis media (COM), and control groups. Through quantitative analysis, we measured the area of cochlear lateral wall structures and observed the presence and the degree of EH using light microscopy. RESULTS: No significant changes were determined in the area of the spiral ligament (p > 0.05) across the species. However, a significant (p < 0.05) decrease in the mean area of the stria vascularis in the basal turn was identified in COM groups compared to controls of both species. Chinchilla model additionally exhibited pathology extending to the lower mid turn. A negative correlation was found between the mean strial area and the severity of EH in both the animal model and human samples. CONCLUSIONS: COM associated with significant changes in the stria vascularis that may lead to significant increase in the degree of EH. The presented animal model exhibited parallel findings with human samples, suggesting its viability as a valuable model for future studies. LEVEL OF EVIDENCE: N/A Laryngoscope, 2024.

Cochlear Otosclerosis and Secondary Hydrops (Ménière's Syndrome).

ABSTRACT: This article discusses a case of cochlear otosclerosis leading to secondary hydrops and near-complete hearing loss. Histopathological examination revealed advanced multifocal otosclerosis in both temporal bones, with specific focus on cochlear invasion and significant bone resorption. The severity of the case ruled out surgical intervention due to the risk of further hearing loss. The article emphasizes the challenges in managing otosclerosis-related hydrops and highlights the potential use of advanced imaging techniques for diagnosis. The study underscores the complexity of otosclerosis-induced hearing loss, contributing to the understanding of this pathology and its impact on auditory function.

Middle Ear Ossicular Joint Changes in Type 2 Diabetes Mellitus: A Histopathological Study.

OBJECTIVES: Although previous research has indicated inner ear changes in diabetes mellitus (DM) patients, no prior study has explored the middle ear, particularly the ossicles and their joints, in DM patients. This study aimed to investigate whether type 2 DM is associated with middle ear changes, specifically affecting the ossicular chain and joints. METHODS: This study included 47 ears from 25 patients with DM (male = 13, female = 12, age: 51.0 ± 20.5) and age- and sex-matched controls (male = 10, female = 10, age: 54.8 ± 15.9) (sex; p = 1.000, Age; p = 0.991). Otopathological evaluations of the auditory ossicles and incudomalleolar joint (IMJ) were performed using light microscopy. RESULTS: In the IMJ of DM cases, malleus hyalinized cartilage (Malleus hC) and incus hyalinized cartilage (Incus hC) were significantly increased compared with control cases (Malleus hC; DM, 34.17 ± 9.71 µm vs. control 21.96 ± 4.16 µm, p < 0.001) (Incus hC; DM 35.11 ± 10.12 µm vs. control 22.42 ± 4.368 µm, p < 0.001). In addition, bone-line distance was significantly longer than in DM cases than control cases (DM 266.72 ± 59.11 µm vs. control 239.81 ± 35.56 µm p = 0.040). On the other hand, joint discus distance was longer in the control group than in DM cases (DM 96.84 ± 36.80 µm vs. Control 113.63 ± 23.81 µm, p = 0.001). CONCLUSIONS: This study reveals a notable increase in the hyalinized cartilage layer and bone-line distance accompanied by reducing joint discus distance within the IMJ in DM cases. These findings suggest that DM may influence microjoints, such as the IMJ, and potentially impact auditory function. EVIDENCE LEVEL: N/A Laryngoscope, 134:2871-2878, 2024.

The role of motor proteins in photoreceptor protein transport and visual function.

BACKGROUND: Rods and cones are photoreceptor neurons in the retina that are required for visual sensation in vertebrates, wherein the perception of vision is initiated when these neurons respond to photons in the light stimuli. The photoreceptor cell is structurally studied as outer segments (OS) and inner segments (IS) where proper protein sorting, localization, and compartmentalization are critical for phototransduction, visual function, and survival. In human retinal diseases, improper protein transport to the OS or mislocalization of proteins to the IS and other cellular compartments could lead to impaired visual responses and photoreceptor cell degeneration that ultimately cause loss of visual function. RESULTS: Therefore, studying and identifying mechanisms involved in facilitating and maintaining proper protein transport in photoreceptor cells would help our understanding of pathologies involving retinal cell degeneration in inherited retinal dystrophies, age-related macular degeneration, and Usher Syndrome. CONCLUSIONS: Our mini-review will discuss mechanisms of protein transport within photoreceptors and introduce a novel role for an unconventional motor protein, MYO1C, in actin-based motor transport of the visual chromophore Rhodopsin to the OS, in support of phototransduction and visual function.

Diversity of the cochlear and vestibular pathologies in human temporal bones of newborns infected with cytomegalovirus.

Hypothesis: Human temporal bones of newborns with congenital cytomegalovirus (cCMV) infection can be characterized by diverse cochlear and vestibular histopathologies associated with the variability in sensorineural hearing loss (SNHL) and vestibular dysfunction in these newborns. Background: Only a small number of studies on the cochlear and vestibular pathologies in human temporal bones with cCMV infection have been previously reported. Methods: Cochleovestibular histopathologies were evaluated in 4 temporal bones from 3 infants with cCMV infection by light microscopy. Results: In one available temporal bone of the infant in Case 1, no cytomegalic cells were found. Large areas of cellular and non-cellular structures were observed in the scala tympani of the perilymphatic space; however, there was no obvious loss of cochlear or vestibular hair cells. In Case 2, cytomegalic cells, a loss of vestibular hair cells, and a loss of nerve fibers were observed only in the area of dark cells in the vestibular labyrinth of the left temporal bone. No cytomegalic cells were found in the right temporal bone of the same infant; however, there was a loss of outer hair cells in the organ of Corti and hypervascularity in the stria vascularis. The one available temporal bone of the infant in Case 3 showed cytomegalic cells and a loss of hair cells in both cochlear and vestibular parts of the inner ear. Conclusions: Human temporal bones of newborns with cCMV demonstrate diverse cochleovestibular histopathologies. This diversity is consistent with the variable SNHL and vestibular dysfunction reported in infected newborns.

Otopathologic Abnormalities in CHARGE Syndrome.

OBJECTIVE: To perform an otopathologic analysis of temporal bones (TBs) with CHARGE syndrome. STUDY DESIGN: Otopathologic study of human TB specimens. SETTING: Otopathology laboratories. METHODS: From the otopathology laboratories at the University of Minnesota and Massachusetts Eye and Ear Infirmary, we selected TBs from donors with CHARGE syndrome. These TBs were serially sectioned at a thickness of 20 µm, and every 10th section was stained with hematoxylin and eosin. We performed otopathologic analyses of the external ear, middle ear (middle ear cleft, mucosal lining, ossicles, mastoid, and facial nerve), and inner ear (cochlea, vestibule, internal auditory canal, and cochlear and vestibular nerves). The gathered data were statistically analyzed. RESULTS: Our study included 12 TBs from 6 donors. We found a high prevalence of abnormalities affecting the ears. The most frequent findings were stapes malformation (100%), aberrant course of the facial nerve (100%) with narrow facial recess (50%), sclerotic and hypodeveloped mastoids (50%), cochlear (100%) and vestibular (83.3%) hypoplasia with aplasia of the semicircular canals, hypoplasia and aplasia of the cochlear (66.6%) and vestibular (91.6%) nerves, and narrowing of the bony canal of the cochlear nerve (66.6%). The number of spiral ganglion and Scarpa's ganglion neurons were decreased in all specimens (versus normative data). CONCLUSIONS: In our study, CHARGE syndrome was associated with multiple TB abnormalities that may severely affect audiovestibular function and rehabilitation.

Temporal Bone Pathology Secondary to Head Trauma-A Human Temporal Bone Study.

HYPOTHESIS/BACKGROUND: We hypothesize that following head trauma there is a difference in temporal bone (TB) pathology in cases with and without skull fracture. Although conductive, sensorineural, mixed hearing loss, and TB pathology following head trauma have been reported, to our knowledge, there are no studies that have compared the pathology of the TB in cases with and without skull fracture. METHODS: We analyzed 34 TBs from donors who had a history of head trauma (20 with skull fracture and 14 without fracture), and 25 age-matched controls without clinical or histological evidence of otologic disorders. We documented the presence and location of TB fracture, ossicular injury, and cochlear hemorrhage and evaluated the loss of spiral ganglion cells and sensory hair cells, damage to the stria vascularis, and the presence of endolymphatic hydrops. RESULTS: We found a significant loss of outer hair cells in the upper basal, lower, and upper middle turns of the cochlea (p = 0.009, =0.019, =0.040, respectively), a significant loss of spiral ganglion cells (p = 0.023), and cochlear hemorrhage predominantly in the basal turns secondary to head trauma. Interestingly, these findings were significantly observed in TBs from donors with a history of head trauma without skull fracture. CONCLUSION: The greatest damage was to the cochlear basal turn. Our findings suggest that head trauma may result in tonotopic high frequency sensorineural hearing loss. TBs from donors with skull fracture have less pathologic changes than those without.

Formations of Host Fibers and Bacteria in Human Temporal Bones With Otitis Media.

HYPOTHESIS: In temporal bones with otitis media, fibrin and neutrophil extracellular traps (NETs) form a fibrous network with bacteria, which is involved in growth of bacterial clusters/biofilms and chronicity of disease. BACKGROUND: NETs and fibrin are important in host defense against pathogens; however, their role in otitis media is not well understood. METHODS: Eight human temporal bones with serous otitis media, 30 with serous-purulent otitis media, 7 with mucoid otitis media, 23 with mucoid-purulent otitis media (OM), 30 with purulent OM, and 30 with chronic otitis media were selected based on histopathologic findings. Fibrous material with bacteria was detected with hematoxylin-eosin, Gram-Weigert, and propidium iodide stains; and its composition was analyzed with immunohistochemistry. RESULTS: Extensive formations of fibrous material with bacteria were observed in 30% of temporal bones with serous-purulent otitis media, 29% with mucoid otitis media, 50% with mucoid-purulent OM, 57% with purulent OM, and 67% of temporal bones with histological evidence of chronic otitis media. Some of these formations showed large bacterial clusters or biofilms. Immunohistochemical analysis showed that fibrous structures were composed of fibrin or NETs. CONCLUSIONS: Formations of fibrous material with bacteria were detected in human temporal bones with different types of otitis media. Inflammatory cells were observed mostly in areas with low presence of fibrous structures. The network of fibrous material seems to prevent clearance of bacteria by phagocytic cells and thus influences growth of bacterial clusters or biofilms. Fibrin and NETs may be important for the recurrences and chronicity of disease, and contribute to clogging of tympanostomy tubes in children.

Three-Dimensional Analysis of Round Window Membrane in the Chinchilla Model with Acute Otitis Media Induced with Streptococcus Pneumoniae 7F.

OBJECTIVE: The purpose of this study was to investigate the morphological changes of round window membrane (RWM) in chinchillas with Streptococcus pneumoniae (S. pneumoniae) serotype 7F induced acute otitis media (AOM) by two dimensional (2D) and three dimensional (3D) measurements. METHODS: Temporal bone specimens taken from 12 chinchillas were divided into two groups. The control group consisted of healthy animals that were injected with intrabullar saline. The subjects in the experimental group were induced with AOM by intrabullar injection of S. pneumoniae 7F. The 2D and 3D measurements of RWM were compared between the groups. RESULTS: Dramatic changes were noted in the RWM of the experimental group compared to the control group. The thickness [mean ± standard deviation (SD)] of the RWM was significantly (p<0.05) increased in the experimental group compared to the control group by 2D measurements taken at three different points of RWM. Moreover, 3D measurements revealed that the volume (mean ± SD) of RWM was significantly (p=0.009) increased in the experimental group. CONCLUSION: The results of our study, which indicated significant change in RWM in both 2D and 3D measurements, may shed light on the relationship between AOM and inner ear diseases. Based on our results, we recommend evaluating 3D analyses of RWM, which provide useful data, to better understand the changes in the membrane.

Mucopolysaccharidosis Type I: Current Treatments, Limitations, and Prospects for Improvement.

Mucopolysaccharidosis type I (MPS I) is a lysosomal disease, caused by a deficiency of the enzyme alpha-L-iduronidase (IDUA). IDUA catalyzes the degradation of the glycosaminoglycans dermatan and heparan sulfate (DS and HS, respectively). Lack of the enzyme leads to pathologic accumulation of undegraded HS and DS with subsequent disease manifestations in multiple organs. The disease can be divided into severe (Hurler syndrome) and attenuated (Hurler-Scheie, Scheie) forms. Currently approved treatments consist of enzyme replacement therapy (ERT) and/or hematopoietic stem cell transplantation (HSCT). Patients with attenuated disease are often treated with ERT alone, while the recommended therapy for patients with Hurler syndrome consists of HSCT. While these treatments significantly improve disease manifestations and prolong life, a considerable burden of disease remains. Notably, treatment can partially prevent, but not significantly improve, clinical manifestations, necessitating early diagnosis of disease and commencement of treatment. This review discusses these standard therapies and their impact on common disease manifestations in patients with MPS I. Where relevant, results of animal models of MPS I will be included. Finally, we highlight alternative and emerging treatments for the most common disease manifestations.

Quantitative assessment of cochlear and vestibular ganglion neurons in temporal bones with chronic otitis media.

PURPOSE: In this study, we aimed to determine whether or not COM leads to loss of spiral and Scarpa ganglion neurons. METHODS: From the human temporal bone (HTB) collection at the University of Minnesota we selected human temporal bones with COM, defined as the presence of clinically intractable tissue abnormalities in the middle ear (cholesteatoma, perforation of the eardrum, granulation tissue, fibrosis, tympanosclerosis, and cholesterol granuloma). We also selected HTBs from donors with no ear diseases as controls. We quantitatively analyzed the number of spiral and Scarpa ganglion cells and compared the results obtained in the control and study groups. RESULTS: In both COM and control groups we observed a significant negative correlation between age and number of both spiral (R = -0.632; P < 0.001; 95% CI - 0.766 to - 0.434) and Scarpa ganglion (R = - 0.404; P = 0.008; 95% CI - 0.636 to - 0.051) cells. We did not find any significant differences in the number of spiral ganglion cells (in total or per segment) or in the density of Scarpa ganglion cells (in each vestibular nerve or both) in the COM group as compared with controls (P > 0.05). CONCLUSIONS AND RELEVANCE: Our results did not demonstrate significant loss of cochlear or vestibular peripheral ganglion neuron loss in HTBs with COM as compared with controls.

Cochlear turns measurements in patients with meningitis: A histopathological study.

OBJECTIVE: To demonstrate the cochlear turns area changes among patients with a history of meningitis, through otopatologic study. METHODS: We performed an analysis of the area of the bony cochlear turns and the cochlear lumen of the horizontal sections containing the modiolus and the area of the basal turn at the level of round window, in temporal bones obtained from patients with a history of meningitis and compared to a nondiseased control group. RESULTS: The mean area of the bony walls and the lumen of all cochlear turns are reduced within the meningitis group. Patients who presented a time from the diagnosis of meningitis to death longer than 30 days had a significant reduction in the cochlear turns area, as compared to the control group. CONCLUSION: Future studies may further correlate audiologic outcomes, cochlear volume, and cochlear area among patients with meningitis.

A Structural Analysis of Tympanic Compartments of the Middle Ear in Patients With Down's Syndrome: A Temporal Bone Study.

: Hypothesis: There may be findings peculiar to the temporal bones of children with Down's syndrome (DS). The purpose of this study is to investigate the temporal bone histopathology of the children with DS. BACKGROUND: Otitis media with effusion is a highly prevalent condition with DS. Knowledge of the volume of the tympanic compartments and the area of the tympanic isthmus might be important to find out the pathogenesis of highly prevalent otitis media with effusion in those patients. METHODS: We compared the volume of the epitympanum, mesotympanum, and the areas of the tympanic isthmus and tympanic orifice of eustachian tube in temporal bones from patients with DS. We also investigated the eustachian tube histopathologically. RESULTS: The mean volume of the epitympanum and the mesotympanum was significantly smaller in the DS group than the control group. We found no significant difference in the mean diameter of the protympanic opening and tympanic orifice between the two groups. The mean narrowest area of the aerated and bony tympanic isthmus also was not significantly different between the two groups. An immature development of eustachian tube and cartilage was seen. We found mesenchyme remaining at the epitympanum and/or mesotympanum in all specimens in the DS group, and in five specimens in the control group. CONCLUSION: In the presence of the small middle ear, poorly developed eustachian tube, and tensor muscle, a vicious circle occurs, making otitis media with effusion difficult to resolve.

Cytomegalovirus-induced pathology in human temporal bones with congenital and acquired infection.

OBJECTIVE: Publications on histopathology of human temporal bones with cytomegalovirus (CMV) infection are limited. We aim to determine histopathology of the inner ears and the middle ears in human temporal bones with congenital and acquired CMV infections. METHODS: Temporal bones from 2 infants with congenital and 2 adults with acquired CMV infection were evaluated by light microscopy. RESULTS: Two infants with congenital CMV infection showed striking pathological changes in the inner ear. There was a hypervascularization of the stria vascularis in the cochlea of the first infant, but no obvious loss of outer and inner hair cells was seen in the organ of Corti. However, cytomegalic cells and a loss of outer hair cells were found in the cochlea of the second infant. The vestibular organs of both infants showed cytomegalic cells, mostly located on dark cells. There was a loss of type I and type II hair cells in the macula of the saccule and utricle. Loss of hair cells and degeneration of nerve fibers was also seen in the semicircular canals. Both infants with congenital infection showed abundant inflammatory cells and fibrous structures in the middle ear cavity. No evidence of cytomegalic cells and hair cell loss was found in the cochlea or vestibular labyrinth in acquired CMV infection. CONCLUSIONS: In two infants with congenital CMV infection, the cochlea, vestibule, and middle ear were highly affected. Temporal bones of adult donors with acquired viral infection showed histological findings similar to donors of the same age without ear disease.

Histopathology of Inner Ear Malformations: Potential Pitfalls for Cochlear Implantation.

HYPOTHESIS: The presence of bony inner ear malformations may associate with a number of anatomical abnormalities affecting the middle ear structures. Those malformations may create pitfalls and complications for cochlear implantation. BACKGROUND: Inner ear malformations associate with varying degrees of hearing loss, and frequently require cochlear implantation for hearing rehabilitation. Therefore, the abnormalities affecting the middle- and inner-ear structures may increase the risk of surgical complications. METHODS: We examined 38 human temporal bones from donors with bony inner ear malformations. Using light microscopy, we analyzed the presence of abnormalities in the structures of the middle- and inner-ear. RESULTS: Our collection comprises of 38 specimens with inner-ear malformations (cochlear aplasia, n = 3; cochlear hypoplasia, n = 30; incomplete partition, n = 3; isolated vestibular malformation, n = 2). The anatomy of the middle ear was abnormal in most temporal bones with cochlear aplasia, cochlear hypoplasia, and incomplete partition type I (40%-100%). Some of those abnormalities (hypoplastic or obliterated mastoid, 55.2%; aplastic or obliterated round window, 71.0%; aberrant course of the facial nerve, 36.8%) may hinder the access to the round window using the conventional facial recess approach for cochlear implantation. The cochlear nerve and associated bony structures (internal auditory canal and bony canal for cochlear nerve) were normal in 71.0% of all temporal bones with inner ear malformations. CONCLUSION: Each different type of malformation may create specific surgical challenges to surgeons. Comprehensive preoperative imaging is fundamental toward the surgical success of cochlear implants in patients with malformations. Alternatives to circumvent those middle- and inner-ear abnormalities and potential complications are further discussed.

Cochleosaccular (Scheibe) dysplasia in dogs: A temporal bone study.

The objective of this study was to evaluate any otopathologic changes in temporal bone specimens from dogs with deafness related to cochleosaccular (Scheibe) dysplasia (CSD). We used the canine temporal bone collections of the Otopathology Laboratory at the University of Minnesota and of the Massachusetts Eye and Ear Infirmary at Harvard University in Boston. Our morphometric analysis included measuring the areas of the stria vascularis and the spiral ligament and counting the number of spiral ganglion cells. In addition, we noted the presence of the organ of Corti and cochlear hair cells, assessed the location of Reissner's membrane and the saccular membrane, and counted the number of both Type I and Type II vestibular hair cells in the macule of the saccule and vestibular ganglion cells. In the group of specimens from dogs with cochleosaccular dysplasia, we observed generalized degeneration in the cochlea and a significantly decreased number of Type I and Type II vestibular hair cells and vestibular ganglion cells. As hereditary deafness is presently untreatable with known therapeutic methods, dogs with cochleosaccular dysplasia should not be considered for breeding. Future therapeutic approaches, such as stem cell therapies, should be designed to target all the elements of the cochlea in addition to the saccule as it was found that both are affected in dogs with CSD.

L'objectif de la présente étude était d'évaluer tous changements otopathologiques dans des spécimens d'os temporal provenant de chiens avec surdité reliée à de la dysplasie cochléosacculaire (Scheibe) (DCS). Nous avons utilisé la collection d'os temporal canin du Otopathology Laboratory à l'Université du Minnesota et du Massachusetts Eye and Ear Infirmary de l'Université Harvard à Boston. Notre analyse morphométrique incluait de mesurer les régions de la stria vascularis et du ligament spiral et de compter le nombre de cellules du ganglion spiral. De plus, nous avons noté la présence de l'organe de Corti et des cellules ciliées cochléaires, évalué la localisation de la membrane de Reissner et de la membrane sacculaire, et compté le nombre de cellules ciliées vestibulaires de Type I et Type II dans la macule du saccule et les cellules vestibulaires ganglionnaire. Dans le groupe de spécimens provenant de chiens avec dysplasie cochléosacculaire, nous avons observé une dégénérescence généralisée de la cochlée et une diminution significative du nombre de cellules ciliées de Type I et Type II et ces cellules du ganglion vestibulaire. Étant donné que la surdité héréditaire est présentement non-traitable par des méthodes thérapeutiques connues, les chiens avec de la dysplasie cochléosacculaire ne devraient pas être utilisés pour la reproduction. Des approches thérapeutiques futures, telles que les thérapies avec des cellules souches, devraient être planifiées afin de cibler tous les éléments de cochlée en plus du saccule étant donné qu'il a été démontré que les deux sont affectés chez les chiens avec DCS.(Traduit par Docteur Serge Messier).

Bilateral glomus tympanicum tumors: Human temporalbone study.

To describe human temporal bones with bilateral glomus tympanicum tumors. Patient is 83-year-old black female who no pulsatile tinnitus. The histopathologic characteristics of human temporal bones after death were setting Department of Otolaryngology of University of Minnesota in USA. Histopathologic observation of temporal bones showed bilateral small glomus tympanicum tumors limited to the promontory. Although there was bilateral tinnitus, there was no pulsatile tinnitus, no conductive hearing loss and both of the tympanic membranes were intact. Histopathologic observation of temporal bones after death showed bilateral glomus tympanicum tumors. To our knowledge, this is the first reported case of bilateral glomus tympanicum tumors.

Otopathology in the United States: History, Current Situation, and Future Perspectives.

: Human temporal bone studies have documented the pathophysiologic basis of many pathologic conditions and diseases affecting the ear, contributing to the development of specific clinical knowledge and pathology-oriented treatments. Researchers dedicated to the study of anatomy and histology of the temporal bone emanated from Europe to the United States during the first part of the 20th Century. The first otopathology laboratory was founded in the United States in 1924, at Johns Hopkins University; over time, the otopathology laboratories-considered by some authors as "gold mines" for studying ear diseases-became numerous and very prolific. However, today, only three of the temporal bone laboratories are still running and producing scientific knowledge to the Otology/Neurotology field: the ones at Harvard Medical School, University of Minnesota, and University of California. Molecular biologic assay techniques and new microscopy and computer equipment broadened the possibilities for temporal bone studies; however, the current funding for those laboratories are insufficient to cover the costs for processing and studying human temporal bones. The main objective of this study is to briefly describe the history, current situation, and future perspectives of the otopathology laboratories in the United States.

Structural Analysis of Tensor Tympani Muscle, Tympanic Diaphragm, Epitympanum, and Protympanum in Menière's Disease: a Human Temporal Bone Study.

HYPOTHESIS: We hypothesized that there would be significant anatomic differences of the tensor tympani muscle (TTM), tympanic diaphragm, epitympanum, and protympanum in patients with versus without Menière's disease. BACKGROUND: The effects of tenotomy on Menière's disease suggested it relieves the pressure on the inner ear of the contraction of the TTM and of negative middle ear pressure. METHODS: Using human temporal bones from patients with Menière's disease, two studies were conducted. We examined the presence of otitis media, cholesteatoma, and endolymphatic hydrops, the length, diameter, configuration, the volume of the TTM and tendon, and the area of the tympanic isthmus (Study 1). We examined the presence of otitis media, cholesteatoma and endolymphatic hydrops, and the area and volume of the protympanum (Study 2). RESULTS: In study 1, we observed no significant differences between the two groups. In study 2, we did not observe a small and narrow protympanum in the Menière's disease group. None of the ears in the Menière's or control groups had otitis media or cholesteatoma in either study. We observed hydrops in all the temporal bones of the Menière's disease group and none in the control groups. CONCLUSION: The position, configuration, and size of the tensor tympani muscle and tendon do not seem to play a role in the pathogenesis of Menière's disease. Because the tympanic isthmus and protympanum in Menière's disease are not smaller than controls and that none of the temporal bones had otitis media or cholesteatoma, it is unlikely that there was dysventilation in the middle ear.