Congenital Anomalies of the Inner Ear

1984 ◽  
Vol 93 (4_suppl) ◽  
pp. 110-118 ◽  
Author(s):  
Isamu Sando ◽  
Tetsuo Takahara ◽  
Akira Ogawa

This study investigated congenital anomalies occurring in the inner ear, with particular attention to their features, localizations, and frequencies. Seventy-seven human temporal bones obtained from 53 individuals, aged one day to 39 years, each of whom had anomalies of the external ear, middle ear, and/or inner ear, were used for this study. The temporal bones had been removed at autopsy, fixed, dehydrated, embedded in celloidin, and sectioned horizontally or vertically at 20 μm. Every tenth horizontal section or every 20th vertical section was stained with hematoxylin and eosin, mounted, and studied under a light microscope. There were 206 inner ear anomalies (117 in the vestibular system, 79 in the cochlea, 10 in the internal auditory meatus) in the 51 bones studied. Fifty-four different features of anomalies were present at 33 different locations in the inner ear. The most frequent anomalies observed were shortened cochlea (23 bones), enlarged vestibule (17 bones), wide cochlear aqueduct (16 bones), absence of lateral semicircular canal (14 bones), and large osseous lateral semicircular canal (10 bones). The most common site of inner ear anomalies was thus the lateral semicircular canal, which was involved in 46 of the 206 anomalies observed; the anomalies in this organ were variable in type. The implications of inner ear anomalies are discussed as they relate to fetal development, inner ear dysfunction, and clinical interpretation of polytomographic studies.

2020 ◽  
Vol 13 (3) ◽  
pp. 255-260 ◽  
Author(s):  
Sang Hyun Kwak ◽  
Min Ki Kim ◽  
Sung Huhn Kim ◽  
Jinsei Jung

Objectives. The aim of the present study was to evaluate audiologic and vestibular functions in patients with lateral semicircular canal (LSCC) dysplasia/aplasia.Methods. We conducted a retrospective study of a patients with LSCC dysplasia and aplasia at tertiary referral center. The subjects included 15 patients with LSCC dysplasia or aplasia, with or without combined inner ear anomalies. Medical history, temporal bone computed tomography scans, pure-tone audiograms, and vestibular function test results were analyzed.Results. LSCC anomaly was identified in 15 patients (20 ears). Nine patients had unilateral LSCC dysplasia only and showed a mean pure-tone average of 45.5±28.7 dB, while three patients (33.3%) among them had normal hearing. Six patients had bilateral LSCC dysplasia/aplasia combined with other inner ear anomalies and profound bilateral hearing loss. Notably, only four out of 15 patients (26.7%) had dizziness symptoms. On caloric test, patients with isolated LSCC dysplasia showed a 51.8%±29.3% level of canal paresis (eight out of nine patients showed anomalies), whereas patients with bilateral LSCC dysplasia/aplasia presented bilateral vestibular loss. One patient with isolated LSCC underwent video-head impulse test; horizontal canal gain decreased to 0.62 (17% asymmetry) and anterior canal gain was 0.45 (52.6% asymmetry), whereas posterior canal gain was normal.Conclusion. Bilateral LSCC dysplasia/aplasia is comorbid with other inner ear anomalies and presents as profound bilateral hearing loss and vestibulopathy. In contrast, isolated unilateral LSCC dysplasia presents as ipsilateral horizontal canal paresis. Hearing function in isolated LSCC dysplasia is usually, but not always, impaired with varying severity.


Author(s):  
Varun Kannan ◽  
Brandon Tran

AbstractSeveral known genetic causes of sensorineural deafness are associated with dysplasia of inner ear structures, including the cochlea and labyrinth. Here, we present a child with Barakat syndrome and sensorineural hearing loss, found to have multiple inner ear anomalies including partial duplication of the posterior limb of the left lateral semicircular canal. To our knowledge, duplication of the semicircular canal has not previously been reported. This finding expands our understanding of the range of anatomical variations observed in congenital inner ear malformations, and further characterizes the phenotypic manifestations of Barakat syndrome.


1979 ◽  
Vol 88 (2) ◽  
pp. 198-204 ◽  
Author(s):  
Larry E. Davis ◽  
George T. Nager ◽  
Richard T. Johnson

Pathological and virological studies were performed on temporal bones of 23 hamsters which developed tumors subsequent to neonatal inoculation of simian virus 40 (SV40). Four to five months after viral inoculation, 22 hamsters developed undifferentiated sarcomas in the subcutaneous space adjacent to the temporal bone. Nine tumors invaded the temporal bone, occasionally extending to the subarachnoid space but not to the inner ear. Choroid plexus papillomas developed in four animals, with one tumor demonstrating invasion of the cochlear aqueduct, internal auditory canal, and cochlear modiolus. Cells grown from a sarcoma and a choroid plexus papilloma contained tumor antigen and established that the tumors were SV40 virus induced.


1981 ◽  
Vol 89 (5) ◽  
pp. 836-840
Author(s):  
George Roffman ◽  
Richard W. Babin

Despite a great deal of anatomic and physiologic data in animals, controversy still exists over whether or not the perilymphatic space in man is directly connected to the intracranial space via a patent cochlear aqueduct or other fluid channel. Human physiologic data are limited, indirect, and conflicting. Anatomic and pathologic data have heretofor been inadequate for answering the question convincingly. The temporal bones of a 19-year-old woman with central nervous system lymphoblastic leukemia are discussed. The passive-appearing movement of lymphoblasts between cerebrospinal fluid and perilymphatic spaces suggests both a functionally patent cochlear aqueduct and alternate pathways.


1997 ◽  
Vol 106 (12) ◽  
pp. 1082-1086 ◽  
Author(s):  
Boo Hyun Nam ◽  
Seong Ki Yoon ◽  
Chan Il Park

Audiologic and histopathologic examinations were made after occlusion of the lateral semicircular canal in eight guinea pigs. The lateral semicircular canal was drilled out, and then the canal lumens were plugged with muscle pieces. After a serial recording of auditory brain stem responses for 2 months, histologic specimens of the temporal bones were prepared in the lateral semicircular canal plane. One animal developed profound hearing loss due to suppurative labyrinthitis. The other seven animals showed no significant threshold elevation during this period. Histopathologic examination revealed that the bone defect on the lateral canal was replaced with newly formed bone; the perilymphatic and endolymphatic spaces maintained their compartmentalization; and the membranous endolymphatic canal healed to form complete blind ducts. These findings suggest that proper management of the injured semicircular canal is important for maintenance of postoperative hearing.


2018 ◽  
Vol 32 (2) ◽  
pp. 58-59
Author(s):  
Nathaniel W. Yang

A 62-year-old man consulted for recurrent episodes of vertigo lasting from seconds to several minutes. The vertigo was variably described as spinning, lateral swaying, and a feeling of being “unsure of his position in space.” These episodes were noted to have begun when the patient was still in his 20’s. Standard pure tone audiometry revealed a mild-to-moderate downsloping mixed hearing loss in the left ear. Bithermal caloric testing indicated the presence of a significant left-sided peripheral vestibular loss. Due to the fact that the vertigo episodes presented relatively early in life, the possibility of a congenital inner ear malformation was considered as a cause for his symptoms.  Computerized tomographic (CT) imaging of the temporal bone was performed. This clearly showed the left horizontal semicircular canal lacking a central bony island. (Figure 1 and 2) The cochlea, superior and posterior semicircular canals, vestibular and cochlear aqueducts, and ossicular chain were grossly normal. A malformation of the horizontal or lateral semicircular canal is one of the most common inner ear malformations, as it is the last vestibular structure to be formed during inner ear embryogenesis. As such, it may occur in isolation or may be associated with other vestibular, cochlear, or middle ear malformations.1,2  Although vertigo and dizziness are symptoms to be expected in such a condition, existing data indicates that it may be totally asymptomatic, or it may also present as a sensorineural, conductive, or mixed type of hearing loss.1,3   Radiologic imaging is of prime importance in diagnosing such conditions, especially when auditory and/or vestibular symptoms manifest early in life. This case perfectly illustrates the need for such studies, as the patient went undiagnosed for more than forty years!             No definitive statements can be gleaned from existing medical literature with respect to treatment. However, in patients with debilitating vestibular symptoms, management with modalities that selectively target the vestibular system, but spare the auditory system, such as vestibular neurectomy and trans-tympanic aminoglycoside therapy appear to be reasonable options.   References   Johnson J, Lalwani AK. Sensorineural and conductive hearing loss associated with lateral semicircular canal malformation. Laryngoscope 2000 Oct;110(10):1673–1679. DOI:10.1097/00005537-200010000-00019 PMID: 11037823   Casselman JW, Delanote J, Kuhweide R, van Dinther J, De Foer B, Offeciers EF. Congenital malformations of the temporal bone. In: Lemmerling M, De Foer B, editors. Temporal bone imaging. Berlin Heidelberg: Springer-Verlag; 2015, pp. 120-154.   Kim CH, Shin JE, Lee YJ, Park HJ. Clinical characteristics of 7 patients with lateral semicircular canal dysplasia. Res Vestib Sci 2012;11(2):64-68.


2002 ◽  
Vol 111 (5) ◽  
pp. 397-401 ◽  
Author(s):  
Shin-Ichi Haginomori ◽  
Makoto Miura ◽  
Isamu Sando ◽  
Margaretha L. Casselbrant

Three temporal bones obtained at autopsy from 2 patients with CHARGE association (Coloboma, congenital Heart disease, Atresia of choanae, mental Retardation and/or central nervous system anomalies, Genital hypoplasia, and Ear anomalies) were examined histopathologically. Both temporal bones from 1 patient showed multiple anomalies in the middle ear, inner ear, and facial nerve. However, the temporal bone obtained from the other patient showed almost normal structures in the inner ear, middle ear, and eustachian tube. These results are different from those of 2 previous reports of temporal bone histopathology regarding CHARGE association. This difference suggests that CHARGE association may arise not from one etiopathogenetic factor, but from complex factors. Special attention to dehiscent facial canal and perilymphatic gusher during otologic surgery in patients with CHARGE association is discussed.


2016 ◽  
Vol 37 (9) ◽  
pp. 1370-1375 ◽  
Author(s):  
Eric M. Sugihara ◽  
Seilesh C. Babu ◽  
Dennis J. Kitsko ◽  
Michael S. Haupert ◽  
Prasad J. Thottam

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