The Age-Related Orientational Changes of Human Semicircular Canals

OBJECTIVES: Some changes are found in the labyrinth anatomy during postnatal development. Although the spatial orientation of semicircular canals was thought to be stable after birth, we investigated the age-related orientational changes of human semicircular canals during development. METHODS: We retrospectively studied the computed tomography (CT) images of both ears of 76 subjects ranged from 1 to 70 years old. They were divided into 4 groups: group A (1-6 years), group B (7-12 years), group C (13-18 years), and group D (>18 years). The anatomical landmarks of the inner ear structures were determined from CT images. Their coordinates were imported into MATLAB software for calculating the semicircular canals orientation, angles between semicircular canal planes and the jugular bulb (JB) position. Differences between age groups were analyzed using multivariate statistics. Relationships between variables were analyzed using Pearson analysis. RESULTS: The angle between the anterior semicircular canal plane and the coronal plane, and the angle between the horizontal semicircular canal plane and the coronal plane were smaller in group D than those in group A (P<0.05). The JB position, especially the anteroposterior position of right JB, correlated to the semicircular canals orientation (P<0.05). However, no statistically significant differences in the angles between ipsilateral canal planes among different age groups were found. CONCLUSION: The semicircular canals had tendencies to tilt anteriorly simultaneously as a whole with age. The JB position correlated to the spatial arrangement of semicircular canals, especially the right JB. Our calculation method helps detect developmental and pathological changes in vestibular anatomy.

The anatomic relationship around the horizontal segment of petrous internal carotid artery: a study based on reconstructed computed tomography angiography.

PURPOSE: The anatomic relationship around the horizontal segment of petrous internal carotid artery (ICA) is complicated. Relative researches on human patients using radiographic technique are scarce. It is essential to get adequate anatomic knowledge about this region for performing some bypass procedures. METHODS: Using the independent software Mimics, we prospectively studied the 0.45-mm-thick computed tomography angiography (CTA) images of 29 patients (58 sides). All patients' middle cranial fossa and related critical anatomic structures were reconstructed in 3D. Some measurements were established on the multiplanar reconstructed images, including the distance from foramen ovale and foramen spinosum to the petrous ICA; the distance from the lumen of cochlea to the edge of trigeminal impression and petrous ICA; and the length of the horizontal segment of petrous ICA. RESULTS: The horizontal segment of petrous ICA was surrounded by the trigeminal impression, the cochlea and the auditory tube spatially. On the multiplanar reconstructed CTA images, the average distances from foramen ovale and foramen spinosum to the petrous ICA were 4.1 mm and 5.8 mm, respectively; the average distance from the lumen of cochlea to the edge of trigeminal impression and petrous ICA were 8.2 mm and 2.0 mm, respectively; and the mean length of the horizontal segment of petrous ICA was 15.8 mm. CONCLUSIONS: Our results indicate adequate and reliable anatomic information can be obtained using reconstructed CTA on an individualized basis.

Morphological changes associated with low-tone hearing loss in guinea pig models of early endolymphatic hydrops / 生理学报

The present study was to explore the functional and morphological changes in cochleas of guinea pig models of early endolymphatic hydrops. Thirty albino guinea pigs were randomly divided into three groups: control, 4-week model and 8-week model groups. For each group, n = 10. Model groups were operated on the right ears to result in endolymphatic hydrops with the method of slight destruction of endolymphatic sac and duct from extradural posterior cranial fossa approach, and the animals in control group were sham operated. Electrocochleogram recorded by trans-tympanic approach and auditory brainstem response (ABR) were tested in preoperative model groups, control group, 4-week model group and 8-week model group to assess the hearing changes. Histologic morphometry was used to quantify hydrops by testing scala media area (SMA) ratio. Scanning electron microscope was used to assess the changes of cochlea hair cells. The results showed that the summating potential/compound action potential (SP/AP) ratio of electrocochleogram in 4-week model group (0.33 ± 0.14) and 8-week model group (0.43 ± 0.14) increased significantly, compared with that in control group (0.07 ± 0.06). The maximum SMA ratio in 4-week model group (2.64 ± 0.10) and 8-week model group (3.54 ± 0.13) increased significantly, compared with that in control group (1.06 ± 0.08). The results of maximum SMA ratio correlated with SP/AP ratio of electrocochleogram (r = 0.86). The results of hearing threshold of ABR revealed that the operated ears of model groups were higher than the preoperative results at frequencies of 2 kHz and 4 kHz. And the damage of cochlea hair cells in operated ears occurred in apical and subapical turns. These results suggest the increased SP/AP ratio of electrocochleogram can indicate early endolymphatic hydrops. There is low-tone hearing loss in guinea pig models of early endolymphatic hydrops, and it may be associated with the abnormalities of the stereocilia among the outer hair cells in operated ears which occurs in apical and subapical turns.

Analysis of correlation between congenital auricular deformities and middle ear malformations / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To explore the potential value of knowing the relationship between congenital auricular deformities and middle ear malformations.</p><p><b>METHODS</b>A total of 86 patients with congenital auricular deformities and middle ear malformations, including 51 males and 35 females, were admitted from January 2008 to December 2009 to the Eye Ear Nose and Throat Hospital of Fudan University. Fifty-eight patients had unilateral deformities (R:L = 34:24), while 28 were bilateral. One hundred and fourteen ears with congenital auricular deformities were included. High-resolution CT (HRCT) data was obtained from each patient. The auricular deformities were classified into three grades using the Marx H classification system. The modified Jahrsdoerfer grading system was used to score the malformations using HRCT data. The correlation between the grades of auricular deformities and scores of middle ear malformations was analyzed using Spearman rank correlation analysis.</p><p><b>RESULTS</b>The Marx H grades of congenital auricular deformities were 12 patients with grade I, 25 patients with grade II and 77 patients with grade III, while their corresponding Jahrsdoerfer scores were 7.8 ± 2.4, 6.8 ± 2.6 and 6.0 ± 2.8, respectively. The statistical analysis suggested a trend of negative correlation between the Marx H grades of auricular deformities and the Jahrsdoerfer scores of middle ear malformations (r = -0.2386, P = 0.0106).</p><p><b>CONCLUSION</b>There was a trend to a negative correlation between congenital auricular deformities and middle ear malformations.</p>

Three-dimensional morphological measurements of the utricle, saccule and stapes footplate / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To determine the optimal drill area on the footplate with the 3D measurements of the stapes and the vestibular end organs.</p><p><b>METHODS</b>Four temporal bones were extracted from the fresh cadavers and undecalcified polymer-embedded. After serially sectioning, image processing and the 3D precisely reconstruction, a local Cartesian coordinates was established in which the tympanic surface of the footplate was supposed to be XY plane and the Z coordinate axis passed through the central point of the footplate and was vertical to the XY plane. The configurations of the utricle and saccule were delineated quantitatively, and then any distance between one point on the surface of the footplate and another point on the surface of the utricle or saccule and its orientation can be measured.</p><p><b>RESULTS</b>There was a "V" shaped cleft between the utricle and the saccule. The angle of the" V" shaped cleft was 50.31 +/- 19.90 (17.00 - 68.00) degrees. The apex of the cleft directed anterosuperiorly and approached the footplate center, while beneath the posteroinferior part of the footplate was an open and deep area. The vertical distance from the center point of the footplate to the vestibular end organs was (2.20 +/- 0.548) mm, the maximum of 3.0 mm and the minimum of 1.6 mm.</p><p><b>CONCLUSIONS</b>The posterior and inferior quadrant of the footplate may be the optimal drill area for the fenestra.</p>