BACKGROUND AND OBJECTIVES: High-resolution computed tomography provides an excellent method for examination of the middle ear, inner ear anatomy and pathologic changes in the temporal bones. The purpose of this study was to get various measurements of the external auditory canal and temporal bones, and to compare the changes with age and sex. MATERIALS AND METHOD: The various measurements by CT of the external ear canal of normal 50 ears were done. RESULTS: The obtained results were as follows: 1) In both male and female group, the distance from the medial end of EAC to bony-cartilage junction, the distance from medial end of EAC to the lateral end of cartilage, the distance from the superior wall to the inferior wall (coronal EAC isthmus) and the distance from anterior wall to the posterior wall (axial EAC isthmus) increased significantly with age (p<0.05). 2) Compared with the female group, the male group had longer distance from the posterior tympanic plate to the sinus tympani with age (p<0.05). 3) Compared with male group, the female group had longer distance from the posterior EAC wall to the Sigmoid sinus and from the EAC superior wall to the tegmen tympani with age (p<0.05). 4) In both male and female groups, the anterior and inferior angles increased and the posterior and superior angles decreased with age (p<0.05). CONCLUSION: Computed tomographic evaluation can give us to information to operate external ear, middle ear, and inner ear surgery.
Cartilage ; Colon, Sigmoid ; Ear ; Ear Canal* ; Ear, External ; Ear, Inner ; Ear, Middle ; Female ; Humans ; Male ; Temporal Bone*

The feasibility of virtual otoscopy (VO) imaging was evaluated in five dogs with experimentally induced otitis media, two control dogs, and two canine patients with otitis media. VO images of the tympanic cavity and ossicles were generated with commercially available software using raw computed tomography (CT) data. Eight out of 10 ears inoculated with pathogen exhibited obvious clinical signs associated with otitis externa. CT images revealed soft tissue density material occupying the tympanic bulla compatible with otitis media in three dogs with experimentally induced otitis media and two patients. No remarkable features were observed on the radiographs. Four different VO views (ear canal, tympanic bulla, eustachian tube, and ossicular chain) were created. Promontory, cochlea window, tympanic, and septum bulla as well as ossicles were easily and clearly distinguished except for the incus and stapes of the clinical patients. VO images were not more suitable than images created with conventional CT for accurately diagnosing otitis media in this study. However, it appears that VO could be more feasible for assessing the complex structure of the inner ear in dogs with fluid-filled tympanic cavities since fluid accumulation within the tympanic bulla did not affect the evaluation of bony tissue in the middle ear on VO images.
Animals ; Blister ; Cochlea ; Dogs ; Ear ; Ear, Inner ; Ear, Middle ; Eustachian Tube ; Incus ; Otitis Externa ; Otitis Media ; Otoscopy ; Stapes

BACKGROUND AND OBJECTIVES: Locacorten Vioform (Novartis UK) is frequently prescribed for otomycosis. Its component, Clioquinol, also has anti-bacterial properties. Up to this point, its ototoxic potential has not been evaluated. Our objective aims to evaluate Locacorten Vioform’s potential ototoxicity when applied directly to the middle ear cavity. MATERIALS AND METHODS: We performed an experimental prospective animal study in our animal research center with 20 Hartley guinea pigs divided into 2 groups. The first group (experimental) was treated with Locacorten Vioform in one ear and with a physiologic saline solution in the other. The second group (positive control) was treated with concentrated gentamycin in one ear and physiologic saline in the other. Auditory brainstem response measurements were obtained before and after three sets of injections. Statistics were analyzed using a variance analysis with repeated measures. The histological state of cochlear outer hair cells was compared between the two groups using scanning electron microscopy. RESULTS: Average hearing loss in ears treated with Locacorten Vioform was 32.1 dB, compared with a 2.5 dB average loss in the saline-treated ears. Ears treated with gentamycin lost an average of 33.0 dB. There were clinically and statistically significant differences between the two ears of the guinea pigs in both groups (p < 0.001). Scanning electron microscopy revealed severe pericochlear and cochlear inflammation and ossification in the Locacorten Vioform-treated ears. Gentamycin caused significant destruction of outer hair cell architecture. CONCLUSIONS: Locacorten Vioform induces a hearing loss similar to that caused by gentamycin when applied directly to the middle ear of a guinea pig model. Electron microscopy indicates a pericochlear and cochlear inflammatory reaction with ossification.
Animal Experimentation ; Animals ; Clioquinol ; Ear ; Ear, Middle ; Evoked Potentials, Auditory, Brain Stem ; Gentamicins ; Guinea Pigs ; Guinea ; Hair ; Hair Cells, Auditory, Inner ; Hair Cells, Auditory, Outer ; Hearing Loss ; Inflammation ; Microscopy, Electron ; Microscopy, Electron, Scanning ; Otomycosis ; Prospective Studies ; Sodium Chloride

PURPOSE: To determine the computed tomographic (CT) findings of atresia and stenosis of the external auditory canal (EAC), and to describe associated abnormalities in surrounding structures. MATERIALS AND METHODS: We retrospectively reviewed the axial and coronal CT images of the temporal bone in 15 patients (M:F=8:7; mean age, 15.8 years) with 16 cases of EAC atresia (unilateral n=11, bilateral n=1) and EAC stenosis (unilateral n=3). Associated abnormalities of the EAC, tympanic cavity, ossicles, mastoid air cells, eustachian tube, facial nerve course, mandibular condyle and condylar fossa, sigmoid sinus and jugular bulb, and the base of the middle cranial fossa were evaluated. RESULTS: Thirteen cases of bony EAC atresia (one bilateral), with an atretic bony plate, were noted, and one case of unilateral membranous atresia, in which a soft tissue the EAC. A unilateral lesion occurred more frequently on the right temporal bone (n=8, 73%). Associated abnormalities included a small tympanic cavity (n=8, 62%), decreased mastoid pneumatization (n=8, 62%), displacement of the mandibular condyle and the posterior wall of the condylar fossa (n=7, 54%), dilatation of the Eustachian tube (n=7, 54%), and inferior displacement of the temporal fossa base (n=8, 62%). Abnormalities of ossicles were noted in the malleolus (n=12, 92%), incus (n=10, 77%) and stapes (n=6, 46%). The course of the facial nerve was abnormal in four cases, and abnormality of the auditory canal was noted in one. Among three cases of EAC stenosis, ossicular aplasia was observed in one, and in another the location of the mandibular condyle and condylar fossa was abnormal. In the remaining case there was no associated abnormality. CONCLUSION: Atresia of the EAC is frequently accompanied by abnormalities of the middle ear cavity, ossicles, and adjacent structures other than the inner ear. For patients with atresia and stenosis of this canal, CT of the temporal bone is essentially helpful in evaluating these associated abnormalities.
Colon, Sigmoid ; Constriction, Pathologic* ; Cranial Fossa, Middle ; Dilatation ; Ear Canal* ; Ear, Inner ; Ear, Middle ; Eustachian Tube ; Facial Nerve ; Humans ; Incus ; Mandibular Condyle ; Mastoid ; Retrospective Studies ; Stapes ; Temporal Bone*

Teratomas are the tumor derived from the three germ cell layers. Teratomas presented in the middle ear and eustachian tube are extremely rare. Eustachian tube teratoma extends either up to the middle ear, external ear, and mastoid or down to the nasopharynx. Tumors extending up to the middle ear usually present with recurrent ear drainage and rarely present with facial palsy. Our patient underwent transoral removal of pedunculated nasopharyngeal mass prior to excision of the ear canal mass. This lesion could be suspected as a "dumb-bell" teratoma involving the nasopharynx, eustachian tube, the middle ear and the external ear canal. This case demonstrates the importance of ear examination when managing nasopharyngeal lesions that originate from the eustachian tube and middle ear, even if the patient is an infant. We report a case of eustachian mature teratoma in a female child.
Child ; Drainage ; Ear ; Ear Canal ; Ear, External ; Ear, Middle ; Eustachian Tube* ; Facial Paralysis ; Female ; Germ Cells ; Humans ; Infant ; Mastoid ; Nasopharynx ; Teratoma*

PURPOSE: To evaluate the CT and MRI findings of the large endolymphatic duct or sac syndrome (LEDS) and its associated anomalies, with clinical features. MATERIALS AND METHODS: We retrospectively reviewed the MR and CT images of 52 ears obtained from 26 patients with LEDS. We reviewed the clinical findings, audiology testing, and treatment results. The degree of hearing loss was classified from normal to profound, based on pure tone audiometry. The largest areas were measured at each endolymphatic duct and analyzed to determine whether a correlation exists with the degree of hearing loss. We also analyzed the differences in measurements between CT and MRI findings. RESULTS: All 26 patients had some degree of sensorineural hearing loss, which resulted in 18 ears to undergo a cochlear implantation. One patient was diagnosed with Cornelia de Lange syndrome. Five patients had a sudden hearing loss onset. Ten ears had incomplete cochlear partitions, whereas 28 ears had enlarged vestibules. All patients had severe to profound hearing loss. We found no statistical correlation between the size of the largest area of the endolymphatic duct and the degree of hearing loss. The mean area of the endolymphatic ducts, as per an MRI examination, revealed slightly greater areas than the CT findings, although the differences were not significant. CONCLUSION: Enlarged vestibules and incomplete partitions of the cochlea were common anomalies associated with LEDS. We found no statistical correlation between the largest area of the endolymphatic duct or sac with the degree of hearing loss.
Audiology ; Audiometry ; Cochlea ; Cochlear Implantation ; Cochlear Implants ; De Lange Syndrome ; Ear ; Ear, Inner ; Endolymphatic Duct ; Hearing Loss ; Hearing Loss, Sensorineural ; Hearing Loss, Sudden ; Humans ; Retrospective Studies

BACKGROUND AND OBJECTIVES: Although the role of aquaporin-2 (AQP2) in the kidney has been well defined, its role in the inner ear remains to be determined. The present study was to investigate the effect of water deprivation on the expression of AQP2 in the inner ear. MATERIALS AND METHOD: Healthy male guinea pigs weighing 250 g were used. The experimental group underwent water restriction and the control underwent water loading with sucrose-containing water for 3 days. Concentrations of plasma arginine-vasopressin (AVP) were determined and electrocochleography (ECoG) recordings were made. An RT-PCR, real-time PCR and Westernblotting analysis were used for quantitative analysis of AQP2 mRNA and AQP2 protein expression. Immunohistochemistry was also used to evaluate the distribution of AQP2 water channel proteins in the inner ear. RESULTS: AQP2 was mainly expressed in the epithelium of endolymphatic sac, spiral limbus, spiral ligament and stria vascularis of scala media. The concentrations of plasma AVP were 9.2+/- 0.8 pg/mL in the experimental group and 0.78+/-0.3 pg/mL in the control. The summation potential/ action potential (SP/AP) ratio in ECoG was markedly increased in the experimental group (0.55 in the experimental and 0.29 in the control). RT-PCR and real time PCR as well as Western blot analysis showed that the level of AQP2 mRNA and protein in the cochlea and endolymphactic sac of the water-deprived group was significantly higher than those in the control group. CONCLUSION: These data suggest that AQP2 is one of the important water channels in fluid homeostasis in the inner ear. Moreover, the volume of endolymphatic space can be increased via AVP-AQP2 system in response to water deprivation.
Action Potentials ; Animals ; Aquaporin 2 ; Aquaporins ; Arginine Vasopressin ; Audiometry, Evoked Response ; Blotting, Western ; Cochlea ; Cochlear Duct ; Ear, Inner ; Endolymphatic Hydrops ; Endolymphatic Sac ; Epithelium ; Guinea ; Guinea Pigs ; Homeostasis ; Humans ; Immunohistochemistry ; Kidney ; Male ; Plasma ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; Spiral Ligament of Cochlea ; Stria Vascularis ; Water Deprivation

This paper makes persuasive demonstrations on some problems about the human ear sound transmission principle in existing physiological textbooks and reference books, and puts forward the authors' view to make up for its literature. Exerting the knowledge of lever in physics and the acoustics theory, we come up with an equivalent simplified model of manubrium mallei which is to meet the requirements as the long arm of the lever. We also set up an equivalent simplified model of ossicular chain--a combination of levers of ossicular chain. We disassemble the model into two simple levers, and make full analysis and demonstration on them. Through the calculation and comparison of displacement amplitudes in both external auditory canal air and internal ear lymph, we may draw a conclusion that the key reason, which the sound displacement amplitude is to be decreased to adapt to the endurance limit of the basement membrane, is that the density and sound speed in lymph is much higher than those in the air.
Acoustics ; Ear Canal ; Ear Ossicles ; physiology ; Ear, Inner ; physiology ; Humans ; Lymph ; Models, Anatomic ; Sound

Circling mouse (C57BL/6J-cir/cir) deleted the transmembrane inner ear (Tmie) gene is an animal model for human non-syndromic recessive deafness, DFNB6. In circling mouse, hair cells in the cochlea have degenerated and hair bundles have become irregularity as time goes on. Tmie protein carries out a function of the mechanoelectrical transduction channel in cochlear hair cells. Myosin7a (MYO7A) protein has key roles in development of the cochlear hair bundles as well as in the function of cochlear hair cells. To find whether Tmie protein interacts with MYO7A proteins in the cochlea postnatal developmental stage, we investigated expression of the MYO7A proteins in the cochlear hair cells of circling mice by western blot analysis and whole mount immunofluorescence at postnatal day 5 (P5). The expression of MYO7A showed statistically significant increase in the cochlea of C57BL/6J-+/cir and C57BL/6J-cir/cir mice than that of C57BL/6J-+/+ mice. The MYO7A intensity of the cochlear hair cells also increased in C57BL/6J-+/cir and C57BL/6J-cir/cir mice compared with those of C57BL/6J-+/+ mice. Taken together, the results indicate that Tmie protein may have an important role with MYO7A protein in the development and maintenance of the stereociliary bundles during postnatal developmental stage of the cochlea.
Animals ; Blotting, Western ; Cochlea ; Deafness ; Ear, Inner ; Fluorescent Antibody Technique ; Hair ; Hair Cells, Auditory* ; Humans ; Mice* ; Models, Animal

BACKGROUND AND OBJECTIVES: Temporal bone is a complicated structure anatomically. Highresolution computed tomography (HRCT) provides a good method for examination of the middle ear, inner ear anatomy and pathologic changes in the temporal bones. The purpose of this study is to evaluate the relations of facial nerve and other structures in temporal bone and factors influencing access to posterior tympanotomy according to the age, sex and degree of temporal bone pneumatizaton. SUBJECTS AND METHOD: A total of 133 ears of temporal bone computer tomograph (TBCT) were analyzed. We measured the distances and angle between important surgical landmarks, and compared the data according to the age, sex and mastoid pneumatization. RESULTS: We presented the angle between the posterior wall of external auditory canal and the facial nerve with the index for facial nerve preservation in posterior tympanotomy. This angle is 10.05 degrees other indices are not related statistically. CONCLUSION: This results may enable preoperative assessment and provide background knowledge to prevent facial nerve injury when performing a posterior tympanotomy.
Ear ; Ear Canal ; Ear, Inner ; Ear, Middle ; Facial Nerve ; Facial Nerve Injuries ; Mastoid ; Temporal Bone