Kang-Jae Shin

Quantitative Analysis of the Cochlea using Three-Dimensional Reconstruction based on Microcomputed Tomographic Images

The aim of this study was to provide data on various dimensions of the normal cochlea using three‐dimensional reconstruction based on high‐resolution micro‐CT images. The petrous parts of 39 temporal bones were scanned by micro‐computed tomography (CT) with a slice thickness of 35 μm. The micro‐CT images were used in reconstructing three‐dimensional volumes of the bony labyrinth using computer software. The volumes were used to measure 12 dimensions of the cochlea, and statistical analysis was carried out. The dimensions of cochleae varied widely between different specimens. The mean height and length of the cochlea were 3.8 and 9.7 mm, respectively. The angle between the basal and middle turns was slightly larger in males than in females, while none of the other 11 dimensions differed significantly between males and females. The cochlear accessory canals were observed in about half of the cases (51.3%). Correlation analysis among measured items revealed positive correlations among several of the measured dimensions. The present study could investigate the detailed anatomy of the normal cochlea using high‐resolution imaging technologies. The results of the present study could be helpful for the precise diagnosis of congenital cochlear malformations and for producing optimized cochlear implants. Anat Rec, 296:1083–1088, 2013.

A morphometric study of the semicircular canals using micro-CT images in three-dimensional reconstruction.

It is generally accepted that the three semicircular canals are set at right angles to each other and the lateral semicircular canal is smaller than the anterior and posterior semicircular canals. Precise knowledge of the size and spatial relationships of the semicircular canals is vital, and so the 40 petrous parts of the temporal bones were scanned by micro‐CT at a slice thickness of 35 µm. The micro‐CT images were used in reconstructing three‐dimensional models of the bony labyrinth using computer software. Various dimensions of the semicircular canals were measured using the software, and statistical analysis was performed. The anterior semicircular canal was slightly wider than the posterior semicircular canal, and their heights were similar. The radius of curvature of the lateral semicircular canal was 20% smaller than those of the anterior and posterior semicircular canals. The angles between the three canals were not exactly 90 degrees: they were 92.1, 84.4, and 86.2 degrees between the anterior and posterior, anterior and lateral, and posterior and lateral semicircular canals, respectively. We obtained high‐resolution images of the semicircular canals using three‐dimensional reconstruction software, and these were used to precisely measure the angles between the semicircular canals and the area of the distorted circle formed by each semicircular canal. Anat Rec, 296:834–839, 2013.

Three-dimensional study of the facial canal using microcomputed tomography for improved anatomical comprehension.

The aims of this study were to determine the various dimensions of the normal facial canal and to identify the spatial relationships between the facial canal and its adjacent structures using microcomputed tomography (micro‐CT) imaging and three‐dimensional (3D) reconstruction. The petrous parts of 54 temporal bones were scanned using micro‐CT with a slice thickness of 35 μm. The serial micro‐CT images were used to reconstruct 3D volumes of the facial canal and the bony labyrinth with the aid of computer software. These volumes were used to measure 31 dimensions of the facial canal and its spatial relationships with adjacent structures. The length of the meatal segment, the tympanic segment, and the mastoid segment were significantly larger in males than in females (p < 0.05). The narrowest portions of the facial canal were immediately lateral to the meatal foramen in the labyrinthine segment and the midpoint of the tympanic segment. The distance between the origin of the canal for the chorda tympani nerve and midpoint of the stylomastoid foramen was 35.3% of the length of the mastoid segment, and the angle between the tympanic segment and the lateral semicircular canal was 16.3°. The angle between the mastoid segment and the canal for the chorda tympani nerve could be classified into two groups: <180° and >180°. These findings represent supplemental data for improving the detailed understanding of the facial canal anatomy. Anat Rec, 297:1808–1816, 2014.

Location of the inferior oblique muscle origin with reference to the lacrimal caruncle and its significance in oculofacial surgery

Purpose To identify the location of the inferior oblique muscle (IOM) origin with reference to the lacrimal caruncle in order to facilitate safer oculofacial surgery by preventing morbidity associated with IOM injury. Methods Thirty-seven intact orbits of 20 embalmed Asian cadavers were dissected. The location of the medial border of the IOM origin was determined with respect to the apex of the lacrimal caruncle. In addition, the size of the IOM origin and the anteroposterior distance from the inferior orbital rim to the anterior border of the IOM origin were measured. Results The IOM origin was located at a mean distance of 1.2 mm lateral and 11.2 mm inferior to the apex of the lacrimal caruncle. In half of the orbits, the IOM origin was situated just on the vertical line through the apex of the lacrimal caruncle. The mean length and width of the IOM origin were 4.3 and 2.7 mm, respectively. The mean anteroposterior distance from the inferior orbital rim to the IOM origin was 1.9 mm. Conclusions The lacrimal caruncle is easily identifiable and a reliable external landmark for prediction of the IOM origin. The IOM origin is located approximately where the vertical line through the apex of the lacrimal caruncle intersects the inferior orbital rim. The findings of this anatomical study of the exact location of the IOM origin can help to improve the safety of oculofacial surgery.

Morphological and morphometric study of the androgenetic alopecic scalp using two- and three-dimensional analysis comparing regional differences.

Androgenetic (male‐type) alopecia (AGA) is caused by genetic and androgenetic effects. The progression of baldness results in smaller hair papillae, thinner hair and a shortened hair cycle. Alopecia occurs mainly in the frontal region and, to a lesser extent, in the occipital region.

Emerging Points of the Supraorbital and Supratrochlear Nerves in the Supraorbital Margin With Reference to the Lacrimal Caruncle: Implications for Regional Nerve Block in Upper Eyelid and Dermatologic Surgery.

BACKGROUND Blocking the supraorbital nerve (SON) and supratrochlear nerve (STN) by injecting anesthetic distal to the surgical site has the advantage in upper eyelid surgery that avoids obscuring the surgical landmarks and compromising the levator function. OBJECTIVE To identify the emerging points of the SON and STN in the supraorbital margin with reference to the lacrimal caruncle. METHODS Forty-nine orbits from 27 embalmed Korean cadavers were dissected. The lacrimal caruncle and facial midline were used as landmarks. The emerging points of the SON and STN in the supraorbital margin were determined. RESULTS The emerging points of the SON and STN were, respectively, located at 3.0 mm lateral and 3.3 mm medial to the vertical line through the apex of the lacrimal caruncle along the supraorbital margin. The horizontal distances from the facial midline to the emerging points of the SON and STN were 22.8 and 15.2 mm, respectively. CONCLUSION The optimum sites for achieving SON and STN block are, respectively, located approximately 3 mm lateral and 3 mm medial to the vertical line through the apex of lacrimal caruncle along the supraorbital margin. This knowledge will help the surgeon achieve an easy and accurate approach for regional nerve block.

Anatomy of the lateral femoral cutaneous nerve relevant to clinical findings in meralgia paresthetica.

Introduction: Compression of the lateral femoral cutaneous nerve (LFCN), known as meralgia paresthetica (MP), is common. We investigated the topographic anatomy of the LFCN focusing on the inguinal ligament and adjacent structures. Methods: Distances from various bony and soft‐tissue landmarks to the LFCN were investigated in 33 formalin‐embalmed cadavers. Results: The mean distance from the anterior superior iliac spine (ASIS) to the LFCN was 8.8 mm. In approximately 90% of cases, the LFCN lay <2 cm from the medial tip of the ASIS, whereas, in 76% of cases, it was <1 cm away. The mean angle between the inguinal ligament and LFCN was 83.3°. Conclusions: We determined the variability of the location of the LFCN at the boundary between the pelvic and femoral portions. The reported results will be helpful for diagnosis and treatment of MP. Muscle Nerve 55: 646–650, 2017

Topographic relationships between the transverse facial artery, branches of the facial nerve, and the parotid duct in the lateral midface in a Korean population.

BackgroundThe aims of the present study were to clarify the topographic relationships between various structures in the lateral midface and to provide important anatomical information pertinent to face lifting or treatment of damage to the midface structure. MethodsThirty-two fixed cadavers were dissected (23 males and 9 females; mean age, 66.8 years) and 55 sides of midface were used. The transverse facial artery (TFA), zygomatic branch (Zb) and buccal branch (Bb) of the facial nerve, and the parotid duct (PD) were identified. The structures of the lateral midface were measured relative to the zygion and tragion. The vertical average distances from the zygion to each structure increased in the following order: ZB of the facial nerve, TFA, first Bb of the facial nerve, and PD. The horizontal average distance from the tragion to the point of emergence from anterior border of the parotid gland was also measured. ResultsThe TFA was the closest and the third Bb of the facial nerve was the farthest away. The angles between the horizontal line and ZB of the facial nerve, TFA, PD, and first Bb of the facial nerve were +10.4, −2.3, −18.5, and −27.1 degrees, respectively. ConclusionsThese results may be used to establish the precise locations and the courses of the important midface structures, and represent valuable data that may help to prevent complications during surgery for face lifting and reconstruction of the facial nerve and PD.

Centralization or decentralization of facial structures in Korean young adults.

AbstractIt is well known that facial beauty is dictated by facial type, and harmony between the eyes, nose, and mouth. Furthermore, facial impression is judged according to the overall facial contour and the relationship between the facial structures. The aims of the present study were to determine the optimal criteria for the assessment of gathering or separation of the facial structures and to define standardized ratios for centralization or decentralization of the facial structures.Four different lengths were measured, and 2 indexes were calculated from standardized photographs of 551 volunteers. Centralization and decentralization were assessed using the width index (interpupillary distance / facial width) and height index (eyes-mouth distance / facial height). The mean ranges of the width index and height index were 42.0 to 45.0 and 36.0 to 39.0, respectively. The width index did not differ with sex, but males had more decentralized faces, and females had more centralized faces, vertically. The incidence rate of decentralized faces among the men was 30.3%, and that of centralized faces among the women was 25.2%.The mean ranges in width and height indexes have been determined in a Korean population. Faces with width and height index scores under and over the median ranges are determined to be “centralized” and “decentralized,” respectively.

Assessment of Normal Eyeball Protrusion Using Computed Tomographic Imaging and Three-Dimensional Reconstruction in Korean Adults.

ABSTRACT Purpose: The aim of the present study was to assess normal eyeball protrusion from the orbital rim using two- and three-dimensional images and demonstrate the better suitability of CT images for assessment of exophthalmos. Methods: The facial computed tomographic (CT) images of Korean adults were acquired in sagittal and transverse views. The CT images were used in reconstructing three-dimensional volume of faces using computer software. The protrusion distances from orbital rims and the diameters of eyeballs were measured in the two views of the CT image and three-dimensional volume of the face. Relative exophthalmometry was calculated by the difference in protrusion distance between the right and left sides. Results: The eyeball protrusion was 4.9 and 12.5 mm in sagittal and transverse views, respectively. The protrusion distances were 2.9 mm in the three-dimensional volume of face. There were no significant differences between right and left sides in the degree of protrusion, and the difference was within 2 mm in more than 90% of the subjects. Conclusions: The results of the present study will provide reliable criteria for precise diagnosis and postoperative monitoring using CT imaging of diseases such as thyroid-associated ophthalmopathy and orbital tumors.