Vertically oriented internal auditory canal in an 8-year-old with hearing loss (original) (raw)
Related papers
Abnormal direction of internal auditory canal and vestibulocochlear nerve
The Journal of Laryngology & Otology, 2004
Several internal auditory canal (IAC) anomalies have been reported. To our knowledge, only one case with an abnormal direction of the IAC has been reported in an infant with Pierre Robin syndrome. In this paper, we present the first report of two non-syndromic cases with abnormal IAC direction.
Morphometric Analysis of the Internal Auditory Canal by Computed Tomography Imaging
Iranian Journal of Radiology, 2012
Many clinical and experimental studies have been done to analyze the anatomical and functional aspects of the internal auditory canal (IAC) in human beings since there are great inter-individual variability and structural variations that may occur regarding the other adjacent structures. Objectives: The purpose of this study was to characterize the morphology of the internal auditory canal (IAC) during development using high resolution computed tomography (CT) and to analyze its dimensions, which will be determined by measuring the nearby areas and structures using a system of digital image processing. Patients and Methods: CT images of the IAC of 110 normal subjects aged 1 to 92 years (mean age, 46.5 years) of both genders were reviewed to determine the shape, area, opening width (OW), longitudinal length (LL), vertical diameter (VD) and distance from the vestibular aqueduct. Results: The shapes observed in children and adults were funnel-shaped (74% and 58.3%, respectively), cylindrical (22% and 30.9%, respectively) and bud-shaped (4% and 10.8%, respectively). The measurements by CT in children were: area= 50.30 mm 2 , OW = 7.53 mm, length = 11.17 mm, VD = 4.82 mm and the distance between the IAC and the vestibular aqueduct (VA) = 12.63 mm. In adults, the measurements were: area = 44.64 mm 2 , OW = 7.10 mm, length = 9.84 mm, VD = 4.47 mm and the distance between IAC and VA = 11.17 mm. Conclusions: CT images showed that the IAC has different shapes and when the measurements obtained for children were compared with those of adults, the parameters that presented statistically significant differences in either gender were length and diameter.
Many clinical and experimental studies have been done to analyze the ana tomical and functional aspects of the internal auditory canal (IAC) in human beings since there are great inter-individual variability and structural variations that may occur regard ing the other adjacent structures. Objectives: The purpose of this study was to characterize the morphology of the internal auditory canal (IAC) during development using high resolution computed tomography (CT) and to analyze its dimensions, which will be determined by measuring the nearby areas and structures using a system of digital image processing. Patients and Methods: CT images of the IAC of 110 normal subjects aged 1 to 92 years (mean age, 46.5 years) of both genders were reviewed to determine the shape, area, open ing width (OW), longitudinal length (LL), vertical diameter (VD) and distance from the ves tibular aqueduct. Results: The shapes observed in children and adults were funnel-shaped (74% and 58.3%, respectively), cylindrical (22% and 30.9%, respectively) and bud-shaped (4% and 10.8%, re spectively). The measurements by CT in children were: area= 50.30 mm 2 , OW = 7.53 mm, length = 11.17 mm, VD = 4.82 mm and the distance between the IAC and the vestibular aque duct (VA) = 12.63 mm. In adults, the measurements were: area = 44.64 mm 2 , OW = 7.10 mm, length = 9.84 mm, VD = 4.47 mm and the distance between IAC and VA = 11.17 mm. Conclusions: CT images showed that the IAC has different shapes and when the measure ments obtained for children were compared with those of adults, the parameters that pre sented statistically significant differences in either gender were length and diameter.
Narrow duplicated internal auditory canal: radiological findings and review of the literature
Pediatric Radiology, 2005
Narrow duplicated internal auditory canal (IAC) is a rare malformation of the temporal bone that is associated with ipsilateral congenital sensorineural hearing loss. This may be an isolated finding or a part of a syndrome. Radiological examination should demonstrate aplasia or hypoplasia of the neural components of the narrow IAC, to guide the surgical approach. We report a 7-year-old boy with Klippel-Feil syndrome with a narrow double IAC with no sensorineural hearing loss but with conductive hearing loss. In this patient, the IAC consisted of two separate narrow bony canals clearly seen on 3D temporal bone CT and one nerve that was delineated on MRI. The contralateral external auditory canal was stenotic and the ossicles were dysplastic.
2013
Purpose: Prior studies have associated gross inner ear abnormalities with pediatric sensorineural hearing loss (SNHL) using computed tomography (CT). No studies to date have specifically investigated morphologic inner ear abnormalities involving the contralateral unaffected ear in patients with unilateral SNHL. The purpose of this study is to evaluate contralateral inner ear structures of subjects with unilateral SNHL but no grossly abnormal findings on CT. Materials and methods: IRB-approved retrospective analysis of pediatric temporal bone CT scans. 97 temporal bone CT scans, previously interpreted as ''normal'' based upon previously accepted guidelines by board certified neuroradiologists, were assessed using 12 measurements of the semicircular canals, cochlea and vestibule. The control-group consisted of 72 ''normal'' temporal bone CTs with underlying SNHL in the subject excluded. The study-group consisted of 25 normal-hearing contralateral temporal bones in subjects with unilateral SNHL. Multivariate analysis of covariance (MANCOVA) was then conducted to evaluate for differences between the study and control group. Results: Cochlea basal turn lumen width was significantly greater in magnitude and central lucency of the lateral semicircular canal bony island was significantly lower in density for audiometrically normal ears of subjects with unilateral SNHL compared to controls. Conclusion: Abnormalities of the inner ear were present in the contralateral audiometrically normal ears of subjects with unilateral SNHL. These data suggest that patients with unilateral SNHL may have a more pervasive disease process that results in abnormalities of both ears. The findings of a cochlea basal turn lumen width disparity >5% from ''normal'' and/or a lateral semicircular canal bony island central lucency disparity of >5% from ''normal'' may indicate inherent risk to the contralateral unaffected ear in pediatric patients with unilateral sensorineural hearing loss. ß
Bilateral narrow duplicated internal auditory canal
European Archives of Oto-Rhino-Laryngology, 2008
Internal auditory canal (IAC) anomalies are rare malformations that may include alterations of shape, size or orientation of the IAC. Bilateral duplication of IAC is a very rare malformation and only one case has been described in literature. We report a case of bilateral duplicated IAC together with other inner ear anomalies.
Morphometry of the external auditory canal: Radiological study
Journal of Surgery and Medicine, 2020
Aim: Morphometry of the external auditory canal was not previously studied among the normal population in the literature. In this study we aimed to indicate normal values and age, gender, and side related changes of the external auditory canal of healthy individuals. Methods: Computed Tomography (CT) images of 379 patients were evaluated in this cross-sectional study. Two diameters at three points were measured on sagittal images for each side: First point was at the level of the tympanic membrane where chorda tympani leaves the bony canal. The height (1a) and width (1b) were measured from the ground where the cylindrical view of EAC was most prominent. The second point was at isthmus level, where height (2a) and width (2b) were measured. The third point was the most lateral site of external auditory canal (EAC) at the level of the tympanomastoid suture where height (3a) and width (3b) were measured. Age, gender, and side related changes for each measurement were statistically analyzed. Results: The diameter of each point in each direction was similar between the left and right sides. The median diameter of left 1a was 9.4 mm in males and 9.2 mm in females, which was significantly different. The "a" diameter of each point was higher in males than females for both sides. There was no significant difference between males and females in terms of b diameters. Diameter 1b was higher on the left side compared to the right side for females, while left-right side comparisons for other measurements were similar. None of the diameters differed between the left and right sides for males. Conclusion: Normal measurements of EAC diameters and its age, sex and side related changes are important for surgeons, radiologists, and anatomists. Proper evaluation of EAC is critical for transcanal endoscopic ear surgery and early diagnosis of a pathology impairing the anatomy of EAC on radiologic images.
Narrow, duplicated internal auditory canal
Neuroradiology, 2003
A narrow internal auditory canal (IAC) constitutes a relative contraindication to cochlear implantation because it is associated with aplasia or hypoplasia of the vestibulocochlear nerve or its cochlear branch. We report an unusual case of a narrow, duplicated IAC, divided by a bony septum into a superior relatively large portion and an inferior stenotic portion, in which we could identify only the facial nerve. This case adds support to the association between a narrow IAC and aplasia or hypoplasia of the vestibulocochlear nerve. The normal facial nerve argues against the hypothesis that the narrow IAC is the result of a primary bony defect which inhibits the growth of the vestibulocochlear nerve.
CT and MR imaging of congential abnormalities of the inner ear and internal auditory canal
European Journal of Radiology, 2001
The embryology of the inner ear must be known as many of the inner ear malformations present as a result of the arrest during the various stages of embryology. These malformations are described in this 'embryologic' perspective and specific names for certain malformations are no longer used. Both CT and MR can be used to look at inner ear malformations but often both techniques are complementary. However, CT is preferred when associated middle-or external ear malformations must be excluded. Magnetic resonance is preferred when subtle changes in the membranous labyrinth or abnormalities of the nerves in the internal auditory canal must be visualised. The CT and MR technique must however be adapted as more and more subtle congenital malformations can only be seen when the right technique is used. The heavily T2-weighted gradient-echo or fast spin-echo MR techniques are mandatory if malformations of the inner ear must be excluded. The purpose of this paper is to describe the techniques used to study these patients and to give an overview of the most frequent and important congenital malformations which can be found in the inner ear and internal auditory canal/cerebellopontine angle. : S 0 7 2 0 -0 4 8 X ( 0 1 ) 0 0 3 7 7 -1