Keguang Chen

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.

A New Three-Dimensional Template for the Fabrication and Localization of an Autogenous Cartilage Framework during Microtia Reconstruction.

Aims: To assist with the accurate fabrication and localization of a costal cartilage framework for auricular reconstruction, three-dimensional (3D) digital and solid templates including the auricle and guide plate were made for microtia patients. Methods: The computed tomography data of 60 patients with microtia were included. The 3D digital template of the auricle and guide plate on the healthy side was shaped using MIMICS software with graphic image processing and 3D reconstruction technology. The 3D digital template on the affected side was produced by mirror technique and made into a solid template for clinical application. Results: All 60 patients had a good result of the location and the appearance of the constructed auricle. The time of operation was decreased by an average of half an hour. An individualized 3D solid model of the reconstructed auricular template on the affected side was successfully produced and used in auricular reconstruction. Conclusions: The new 3D template of the auricle and guide plate may be a major contribution to the engraving, assembling and localization of the microtia auricle in auricular reconstruction.

Anatomic measurements of the posterior tympanum related to the round window vibroplasty in congenital aural atresia and stenosis patients

Abstract Conclusions With the aggravation of the external auditory canal malformation, the size of extra-niche fossa became smaller, providing concrete data and valuable information for the better design, selecting and safer implantation of the transducer in the area of round window niche. Three-dimensional measurements and assessments before surgery might be helpful for a safer surgical approach and implantation of a vibrant soundbridge. Objectives The aim of this study was to investigate whether differences exist in the morphology of the posterior tympanum related to the round window vibroplasty among congenital aural atresia (CAA), congenital aural stenosis (CAS), and a normal control group, and to analyze its effect on the round window implantation of vibrant soundbridge. Methods CT images of 10 normal subjects (20 ears), 27 CAS patients (30 ears), and 25 CAA patients (30 ears) were analyzed. The depth and the size of outside fossa of round window niche related to the round window vibroplasty (extra-niche fossa)and the distances between the center of round window niche and extra-niche fossa were calculated based on three-dimensional reconstruction using mimics software. Finally, the data were analyzed statistically. Results The size of extra-niche fossa in the atresia group was smaller than in the stenosis group (p < 0.05); furthermore, the size of extra-niche fossa in the stenosis group was smaller than that of the control group (p < 0.05). There was no statistically significant difference of the depth of extra-niche fossa among different groups.

Morphological Characteristics of Round Window Niche in Congenital Aural Atresia and Stenosis Patients.

Objective The aim of this study was to measure the round window niche (RWN) among congenital aural atresia (CAA), congenital aural stenosis (CAS) and control groups and to analyze whether differences exist between them. Methods Computed tomography images of 10 normal subjects (20 ears), 27 CAS patients (30 ears) and 25 CAA patients (30 ears) were analyzed. We measured RWN on the basis of 3-dimensional reconstruction. Results The anterior wall length and the depth of RWN were smaller in control group than those in the CAS group; furthermore, the anterior wall length and the depth of RWN in CAS group were smaller than those in CAA group (P < 0.05). The posterior wall length of RWN was found smaller in the control group than that in both hCAS and CAA groups (P < 0.05). The superior and inferior wall lengths of RWN were found smaller in control group than those in the CAA group (P < 0.05). There were no statistically significant differences in the sizes of the round window membrane and niche opening or the angle between the plane of the RWN opening and the round window membrane plane among all groups. Conclusions The RWN walls lengths and its depth tended to be longer with the aggravation of the aural malformations. Our calculation results may provide some information for a better design and a safer implantation of the floating mass transducer in the area of RWN.

The age-related positional and orientational changes of the human cochlea

Abstract Conclusion: The cochleae of children over 6 years old and adults displaced more outward, backward, and downward in comparison with those of children under 6 years. However, the cochlear orientation does not significantly change during postnatal development. Adjacent structures correlated with the cochlear position. Objective: To test whether the cochlear position and orientation, which are important in cochlea implant surgery, change during postnatal development. Methods: CT images of both ears of 76 human subjects were studied. They were divided into three groups: group A (1–6 years old), group B (7–18 years old), and group C (>18 years old). Results: The distances from the cochlea to the median sagittal and coronal planes in group A were smaller than those in group B and group C (p < 0.05), but the distance from it to the Frankfurt plane in group A was larger than that in group C (p < 0.05). The volume of the temporal bone pneumatization and the positions of the jugular bulb and the intrapetrous internal carotid artery positively correlated with the cochlear position (p < 0.05). There were no statistically significant differences in the angles between the central axis of the cochlea and these coordinate planes among age groups.

Age-related changes in the morphological relationship between the supratubal recess and the Eustachian tube

OBJECTIVE To study age-related changes in the morphology of the supratubal recess (STR) and its relationship with the Eustachian tube (ET). METHODS Seventy randomly selected computed tomography (CT) images of non-pathological temporal bones of 49 patients were reviewed retrospectively. The patients were grouped according to age into 4 age groups: group A (0-3 years), group B (4-8 years), group C (9-18 years) and group D (19-50 years). Space analytic geometry was assessed to directly calculate the morphology of the STR and the ET. RESULTS In normal temporal bones, the STR was mostly presented with a solitary cell in life. The length of the STR was significantly longer in group C than that in group A (P<0.05). The width of the STR was declined with age and presented with significant difference among age groups (P<0.05). No significant difference was observed in the height of the STR in whole age groups (P>0.05). The aeration of the STR was intimately related with age-related morphological changes in the ET. But the important factors influencing the aeration of the STR were not always the same in different age stages. CONCLUSION The extended length and declined width of the STR with age were mostly related with the prolonging bony part and inwardly bending cartilaginous part of the ET in children and adolescent aged from 0 to 18 years old. In adults aged more than 18 years old, the narrowed caliber of the tympanic orifice of the ET could induce the decline in the width of the STR with age, but unfolded horizontal cartilaginous part of the ET contributed to stable length and height in aeration of the STR.

Position of the Internal Aperture of Vestibular Aqueduct in Patients With Enlarged Vestibular Aqueduct

OBJECTIVE To investigate the position of the internal aperture of vestibular aqueduct and its relationship to hearing level in patients with enlarged vestibular aqueduct (EVA). METHODS The size of the common crus and the position of the internal aperture of vestibular aqueduct were compared among control subjects, EVA patients with and without other inner ear malformations. Auditory steady-state response thresholds were compared between EVA patients with different positions of internal apertures. RESULTS The common crus in EVA patients was shorter than in control subjects (p < 0.05). The internal aperture of the vestibular aqueduct opened solely into the common crus in control subjects, simultaneously into the common crus and vestibule in almost 45% of EVA patients, solely into the common crus, and the vestibule in almost 30 and 25% of EVA patients, respectively. Auditory steady-state response thresholds at 2000 and 4000 Hz were higher in EVA patients whose internal apertures of vestibular aqueducts opened simultaneously into the common crus and vestibule than in those whose internal apertures opened solely into the common crus. CONCLUSION The common crus is shorter in EVA patients than in control subjects. The internal aperture of the vestibular aqueduct opens solely into the common crus in control subjects. It opens simultaneously into the common crus and vestibule in almost half of the EVA patients. The EVA patients whose internal apertures of vestibular aqueducts open solely into the common crus may have better hearing than those whose internal apertures open simultaneously into the common crus and vestibule.

Morphometric Study of the Vestibular Aqueduct in Patients With Enlarged Vestibular Aqueduct

Objective To test whether there are significant differences in the morphologic features of the enlarged vestibular aqueduct (EVA) and its anatomic relationships with adjacent structures between EVA patients with and without other inner ear malformations. Methods The morphology of vestibular aqueduct, volume of vestibule, and anatomic location of facial nerve (FN) were compared among 3 groups. Group A, 18 control subjects; group B, 32 EVA patients without other inner ear malformations; group C, 14 EVA patients with other inner ear malformations. Results The isthmus of the aqueduct and vestibular volume in group C were larger than those in group B (P < 0.05). Positive correlations were identified between the length of the aqueduct and the vestibular volume in groups B and C. The vertical FN segment in group C located more anteriorly than that in groups A and B (P < 0.05). Conclusions Compared with EVA patients without other inner ear malformations, the aqueduct, and vestibule in EVA patients with other inner ear malformations are larger, the vertical FN segment locates more anteriorly.

Morphological Variation of Subarcuate Artery and Canal in Atresia

Objectives: An aberrant subarcuate artery (SAA) and its related canal are infrequent and asymptomatic. The presence of this variation may cause untoward hemorrhages, if accidentally nicked. Therefore, it is important for otologists to be aware of this entity, and its relative anatomy, to avoid any unexpected complication. We present a case of a 7-year-old girl who presented with right-sided microtia with membranous atresia. Methods: High-resolution computed tomographic scan and three-dimensional reconstruction of the temporal bone showed bilateral enlarged SAA. Results: The width of the right-sided bone canal was between 0.76 and 1.33 mm. The left temporal bone showed the same variation, with the width of the canal consistently greater than 1.0 mm, ranging from 1.07 to 1.23 mm in greatest transverse dimension. Conclusions: The variation proposed in microtia was not previously reported in the literature, which may have important implications for the canal reconstruction.