Anatomic Variants on Computed Tomography in Congenital Aural Atresia and Stenosis

OBJECTIVES: To quantitatively analyzing the anatomic variants on temporal computed tomography (CT) in congenital external auditory canal stenosis (EACS), congenital aural atresia (CAA), and normal ear structure. METHODS: Through a retrospective study, we analyzed 142 temporal high-resolution CT studies performed in 71 microtia patients. The following 6 parameters were compared among the three groups: Marx classification, medial canal diameter, vertical facial nerve (VFN) anterior displacement, tegmen mastoideum position, tympanic cavity volume, and malleus-incus joint or malleus-incus complex (MIC) area. RESULTS: The results showed that the microtia distributions in the Marx classification in these three groups were significantly different, as 86% (31 of 35) of ears with major microtia (third-degree dysplasia) had an atresia, and in 54.8% (23 of 42) of the minor microtic (first-degree or second-degree) ears, the bony or cartilaginous part of the external auditory canal was stenotic. Measurement data also showed that the potential medial canal diameter of the atresia group was obviously shorter than that of the stenosis group. The VFN anterior displacement and temporomandibular joint backward-shift together lead to medial canal diameters in ears with atresic canals that is smaller than those with stenotic canals. The tegmen mastoideum position was not significantly different between the three groups. CONCLUSION: The mal-development of the external auditory canal is significantly associated with auricle and middle ear developmental anomalies. Compared with CAA ears, EACS have better development of the auricle, canal, tympanic cavity and MIC and relatively safer surgical operation except for the position of the tegmen mastoideum and the VFN.

Relationship between 3-d reconstruction of regenerated fibers and functional recovery after mastoid segment of facial nerve was repaired / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To explore the relationship between three-dimensional (3-D) reconstruction of regenerated fibers and functional recovery after mastoid segment of facial nerve was repaired with either end-to-end anastomosis or autogenous great auricular nerve grafting.@*METHOD@#Thirty healthy adult New Zealand white rabbits were randomly divided into two groups: one was end-to-end anastomosis group and another was autogenous great auricular nerve grafting group. Only mastoid segment of right facial nerve of each animal was dissected and the contralateral nerve was as a control. Electromyogram (EMG) were recorded from 5 animals of each group at the 30th d, 90th d and 120th d after operation. After that the nerves were extracted, fixed, decalcified and embedded in paraffin. Samples was sectioned serially at 6 microm and stained with special trichrome stain. All the imagines were imported into Mimics software to reconstruct the 3-D model.@*RESULT@#The significant differences were found in the regenerate fibers on 30 th d,and were found in amplitude of EMG on 30 th d and 90 th d. The image of 3-D reconstruction showed that the myelin sheath were thickening, connected from proximal to the distal gradually after repair.@*CONCLUSION@#The 3-D reconstruction of regenerated nerve fibers partly conformed to the functional recovery after facial nerve trunk was repaired. The functional recovery of facial nerve was related with both the quantity and the quality of regenerated nerve fibers.

Quantitative positioning of facial nerve based on three-dimensional CT image reconstruction of temporal bone / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To explore a set of quantitative methods to determine the position of the facial nerve based on three-dimensional CT reconstruction of temporal bone structures on personal computer, which can provide a series of important parameters for ear and the lateral skull base surgery.@*METHOD@#The internal structures of temporal bone were reconstructed based on a set of axial CT images of adult patients, the complicated relationship and their morphologic characteristics were clearly presented by using Able Software 3D-DOCTOR. The precise measurement of some parameters between facial nerve and its adjacent structures could easily be processed with the software. Based on all obtained data, the relationship of facial nerve and its adjacent structures were effectively summarized and analyzed.@*RESULT@#Three-dimensional images, including the facial nerve, tympanic anulus, auditory ossicles, chochleariform process, pyramidal eminence, internal auditory, the cochlea, semicircular canal, jugular fossa and carotid artery in the temporal bone, were reconstructed. Some parameters obtained from measuring the distance or angle between the facial nerve and its adjacent structures in the three-dimensional models had some extent regularity, which were benefit to design surgical approach and determine the position of facial nerve during relevant operation.@*CONCLUSION@#CT 3D reconstruction can accurately display the detailed internal structures anatomy of the temporal bone and their quantitative spatial relationships.