Peidong Dai

Morphological and positional relationships between the sigmoid sinus and the jugular bulb

The purpose of this study was to determine the quantitative relationships between the positions of the sigmoid sinus (SS) and jugular bulb (JB) and the influence of mastoid pneumatization upon these structures. The investigations were carried out on 116 healthy adult ears based on the axial images of computed tomography (CT). The reference system locating the displacements of the SS and JB was established and the shape and position of the SS and JB were measured. The volume of pneumatization was quantitatively measured based on the serial digital images of CT. The method of partial correlation analysis was used to find the real relationship of two variables from the complicated dependence relationships. There was a tendency for the SS in the males to be situated more laterally and more backwardly, and the JB in the males was situated more laterally with thicker lateral bone wall when compared to the females. When compared to the left side, the SS on the right side tended to protrude more deeply and was situated more laterally and with less thickness of the lateral bone wall. In male, the right SS was situated more anteriorly than the left SS. In female, the right JB was situated more posteriorly than the left JB. There was a tendency for the SS to be situated more medially, to have a thicker lateral bone wall, and to protrude more superficially in the well-pneumatized bones. When the pneumatization was well, the JB tended to be situated more backwards and have a thicker lateral bone wall. However, there was no significant difference of pneumatization between the high JB group and the low JB group. The SS position and JB position changed synchronously in forward–backward or medial–lateral directions. The results suggest that the factors that influence the shape and position of the SS and JB are multiple. The results suggest that the morphological and positional relationships between the SS and the JB are complicated but could be grasped. The development of the cranial base, the temporal bone pneumatization and non-synchronous dural venous development between the right and left sides are considered to contribute to the morphological and positional changes of the SS and JB.

Positional relationship between the facial nerve and other structures of the temporal bone

The quantitative relationships between the position of the mastoid segment of the facial nerve, mastoid pneumatization and the positions of neighbouring structures are undetermined. Using high resolution computed tomography (HRCT), the positions of these structures were measured in 66 normal temporal bones. A new method for measuring the volume of pneumatization in the temporal bone based on the serial digital images of CT was designed. The method of partial correlation analysis was used to find the real relationship of the two variables. The results suggest that the factors that influence the position of the mastoid segment of the facial nerve are complicated and multiple. The development of the cranium including the temporal bone, the temporal bone pneumatization and the variable position of the jugular bulb are considered to be important factors.

Dynamic Analysis of Fluid-Structure Interaction of Endolymph and Cupula in the Lateral Semicircular Canal of Inner Ear

The semicircular canals, composed of lateral, anterior and posterior canals in the inner ear, are the sensors of equilibrium during head rotation movements in the three-dimensional space. Semicircular canals are filled with endolymph confined by the cupula. The study of the relationship between endolymph flow and cupular deformation is important in revealing the semicircular canals biomechanical behavior. To date, there are few studies focusing on the transient endolymph flow and cupular deformation in response to a head rotation motion. The lateral semicircular canal is mainly responsible for the sense of the horizontal rotation movement. In order to figure out the intricate dynamics in the lateral semicircular canal during the head rotation motion, the time evolutions of both endolymph flow and cupular deformation are analyzed in this article by using a fully coupled fluid-structure interaction model. It is shown that the cupular deformation provides cues for understanding the physiology of sensing the head rotation.

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 meta-analysis of the long-term hearing outcomes and complications associated with atresiaplasty.

OBJECTIVE To summarize peer-reviewed literature to evaluate the stability of long-term hearing outcomes with prolonged follow-up, and describe the incidence of complications related to atresiaplasty. DESIGN A literature search of EMBASE, MEDLINE, PubMed, Google Scholar, and Web of Science was performed to identify studies of congenital aural atresia (CAA). STUDY SAMPLE Selected studies were published between 1997 and 2014. The 19 studies covered 964 CAA ears. RESULTS Stenosis and bony regrowth occurred in 14.2% (range from 0% to 30.3%). Lateralization of tympanic membrane (TM) occurred in 7.5% (range from 0% to 18.2%). Facial nerve palsy occurred in 0.5% (range from 0% to 5.0%). Six studies used Air-bone Gap (ABG) to evaluate the short-term and long-term hearing outcomes. The hearing outcomes were performed using meta-analysis, there was no significantly heterogeneity (I(2) = 0%, p = 0.997), and there was a degradation of hearing outcomes with prolonged follow-up (RR = 1.13, 95%CI: 0.98-1.30). CONCLUSION Nearly all studies focus on postoperative stenosis and bony regrowth, but some studies neglect lateralization of TM. Based on available data, which shows a lack of major complications, such as facial nerve palsy, atresiaplasty is a safe procedure. Our meta-analysis indicated that there was a degradation of hearing outcomes with prolonged follow-up.

Hydrodynamic modeling of cochlea and numerical simulation for cochlear traveling wave with consideration of fluid-structure interaction

The cochlea is an important structure in the hearing system of humanity. Its unique structure enables the sensibility to the sound waves of varied frequencies. The widely accepted model of the cochlea is expressed as a long tube longitudinally divided by a membrane named the Basilar Membrane (BM), into two fluid-filled channels. Based on various assumptions for the cochlear fluid and structure, simplified mathematical and mechanical cochlear models were developed to help to understand the mechanism of the complex coupled system in the past decades. This paper proposes a hydrodynamic numerical cochlear model with consideration of the Fluid-Structure Interaction (FSI). In this model, the cochlear lymph is considered as in a Newtonian viscous fluid, and the basilar membrane is modeled as a composite structure. The traveling wave is simulated. Also focusing on the pressure in the fluid field, the results are compared with studies of Peterson and Bogert, where it was assumed that the slow compressive waves are traveling along the BM. Furthermore, the transmitting time of the cochlear traveling wave is also discussed.

A Contour Map of the Ear's Vestibular Apparatus Based on 3D Reconstruction

This article presents a method for developing anatomic contour maps that quantitatively display the vestibular apparatuss 3D spatial configurations. Contour maps are useful tools for determining the appropriate position of the drill and the safe depth and orientation of the installed piston in stapedotomy procedures

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.