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Biomedical subjects

K Hwang

Publications and source records attributed to K Hwang.

At least 19 recordsLinked to original sources
PubMed2002

Skin thickness of Korean adults.

Skin thickness varies considerably between different races and age-groups, between men and women, and between different regions of the body surface. A few authors reported the skin thickness of different regions of the body, but no detailed study have been performed on Asian. We performed 452 biopsies on 28 different regions of the normal skin of Korean men and women. The specimens were stained with hematoxylin-eosin and measured microscopically. The thickness of the skin (epidermis plus dermis) ranged from 521 to 1977 microm; the eyelid, prepuce, and inguinal skin was thinnest (521-626 microm), and the back was thickest (1977 microm). The thickness of the epidermis varied from 31 to 637 microm; skin thickness in the prepuce, eyelid, supraclavicular region, postauricular region, and axilla ranged from 31 to 71 microm; the buttock, dorsum of the hand, and dorsum of the foot were relatively thick (138-189 microm); the palm and sole were thickest (601-637 microm). The thickness dermis varied from 469 to 1942 microm; skin thickness in the eyelid, prepuce, inguinal region, and postauricular region ranged from 469 to 645 microm; the buttock, chest, and anterior neck were relatively thick (1318-1586 microm); the back was thickest (1942 microm). The epidermis accounted for 3.7-16.8% of the entire skin in most regions, except in the palm and sole (40.6-44.6%). Thickness data may be useful in harvesting full- or split-thickness skin grafts.

Adolescent↗
PubMed2001

Congestion of right liver graft in living donor liver transplantation.

BACKGROUND: Left liver graft from a small donor will not meet the metabolic demands of a larger adult recipient. One solution to this problem is to use a right liver graft without a middle hepatic vein (MHV). However, the need for drainage from the MHV tributaries has not yet been described. METHODS: Five right liver grafts without a MHV were transplanted in patients including two hepatitis B virus-cirrhosis, two fulminant hepatic failure and one secondary biliary cirrhosis. The graft weight ranged from 650 to 1,000 g, corresponding to 48 to 83% of the standard liver volume of the recipients. RESULTS: Two of five recipients were complicated with severe congestion of the right median sector immediately after reperfusion, followed by prolonged massive ascites and severe liver dysfunction. One of the patients died of sepsis with progressive hepatic dysfunction 20 days after the operation. CONCLUSIONS: Preservation and reconstruction of the MHV tributaries is recommended to prevent congestion of the right liver graft without MHV.

Body Weight↗
PubMed2001

Pretarsal fat compartment in the lower eyelid.

It is generally accepted that there are three infraorbital fat regions in the lower eyelid; medial, central, and lateral compartments. However, removing only the fat in the lateral compartment does not remove the bulge just below the eyelashes, which is caused by another fat pad. The aim of this study was to describe the anatomy of the pretarsal fat compartment and to demonstrate its clinical implications in lower lid blepharoplasty. Ten cadavers (total 20 lower eyelids) were studied. A skin-muscle flap was reflected to expose the soft pretarsal structures. A small stab incision was made on the lateral portion of the sac containing fat on the tarsus. Methylene blue dye was injected into the sac. Specimens were fixed and sagittal sections in four different planes were prepared for histological analysis. The injected dye remained within the sac and demarcated it as a pear or cone shaped structure. This encapsulated fat compartment sits on the lateral half of the tarsal plate above the lateral compartment fat. Auxillary or submuscular fat is well known. This study, however, designates the pretarsal fat as "encapsulated" in a compartment instead of being unbound. We have named it the "pretarsal fat compartment." Histologically, orbital septal fibers separate "pretarsal fat" from lateral infraorbital fat. It is recommended that fat in the pretarsal fat compartment be removed during lower lid blepharoplasty in order to alleviate the bulge or knoll of the skin just below the lower eyelashes.

Adipose Tissue↗
PubMed2001

The emergence of erythromycin-resistant Streptococcus pyogenes in Seoul, Korea.

High frequencies of erythromycin-resistant streptococci were reported in Japan in the mid-1970s, and in Finland in the late 1980s, related to an increase in the consumption of macrolide antibiotics in these countries. The frequency of erythromycin-resistant Streptococcus pyogenes was reported to be only 2% in 1994, but we know that the susceptibility of the strains to antibiotics had not been tested routinely. We studied the resistance rates of Streptococcus pyogenes to various antibiotics in Seoul, Korea, where antibiotics could be purchased without prescription. From January through December, 1998, 92 isolates of group A streptococci were collected from inpatients and outpatients with pharyngotonsillitis or invasive streptococcal infections, from institutions in five different geographic areas of Seoul; one pediatric clinic, three university hospitals, and one general hospital. All isolates were serotyped by T-agglutination, and minimum inhibitory concentrations (MICs) were determined by agar dilution methods, according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). The most common T-serotype was T12 (44.6%), followed by T4 (19.6%). All the isolates tested were susceptible to penicillin, vancomycin, and cefotaxime. However, 38 isolates (41.3%) were resistant to erythromycin, 32 (34.8%) were resistant to clindamycin, and 48 (52.1%) were resistant to tetracycline. Twenty-seven of 41 isolates serotyped T12 and 3 of 18 isolates serotyped T28 were multiresistant to erythromycin, clindamycin, and tetracycline. Almost half of the isolates obtained from the five different areas in Seoul showed erythromycin resistance in Streptococcus pyogenes. Routine monitoring of antibiotic susceptibility tests and further extensive nationwide surveys are needed to determine the frequency and the extent of the spread of resistant strains in various geographic regions in Korea.

Adolescent↗
PubMed2001

Decussation patterns of the platysma in Koreans.

The importance of the platysma muscle in plastic surgery is well known. During surgery, we have observed that the platysmal fibres do not merely decussate and interlace from each side but that sometimes one side of the muscle overlaps and covers the other side. The aim of this study was to clarify the precise anatomical variations in the decussation and overlapping patterns of the platysma muscle in 70 Korean cadavers. We defined three groups (types I--III) and four patterns (types A--D) according to the length of decussation and the pattern of overlapping, respectively. In 60 specimens (85.7%) we observed decussation and in 10 (14.3%) we did not. In type I there was 0--20 mm of decussating fibres below the mandibular border (43% of specimens). In type II, the decussation of fibres extended over more than 20 mm (43% of specimens). Type III had no decussation (14% of specimens). The proportions of type A (interlacing pattern), type B (right dominant), type C (left dominant) and type D (no decussation) were 41%, 29%, 16% and 14%, respectively. In 45% of the specimens, one side of the platysma covered and overlapped the other side. This is relevant to the removal of the subplatysmal fat in corset platysmaplasty, submental Z-plasty and vertical myectomy of the platysma muscle.

Adult↗
PubMed2001

Could ionizing radiation forestall cauliflower ear?

Repeated trauma to the ear very often results in "cauliflower ear." Many methods have been suggested to prevent an injured ear from demonstrating a cauliflowerlike deformity. The principles of treatment are evacuation of the hematoma, control of the reaccumulation of fluid, and maintenance of the cartilage contour. The authors studied the effect of ionizing radiation on deformed rabbit ears induced by repeated trauma. Twenty ears (10 rabbits) were used in the experiment. The animals were divided into four groups (control, preradiation, low dose, and high dose). Hematoma was produced by pounding the lateral side of the auricle 10 times with a 50-g weight at a height of 15 cm. The thickness of the injured and uninjured sites was measured, and histological analysis was performed for each group. The thickness of the ears of the irradiated groups was significantly less than the control group. The authors think that radiation treatment of repeatedly injured ears could prevent ear deformity, and could possibly be an adjunctive form of management of cauliflower ear in addition to hematoma evacuation and compression therapy.

Animals↗
PubMed2001

An anatomic comparison of the skin of five donor sites for dermal fat graft.

Kim performed more than 3,000 augmentation rhinoplasties using the dermal fat graft. He preferred the sacral area as the donor site over other areas because the dermis is thick and the fat is more compact. The authors conducted a comparative study of the thickness of the epidermis and dermis, and the numbers of fibroblasts and fibrocytes in the dermis of the abdominal wall, groin, lateral gluteal area, gluteal fold, and sacrum of 7 adult cadavers. The sacrum had the thickest epidermis (86.1 +/- 7.8 microm) and dermis (1,510.7 +/- 201.7 microm), and the groin had the thinnest epidermis (57.3 +/- 22.9 microm) and dermis (783.3 +/- 244.5 microm). The dermal thickness of the abdomen, lateral gluteal area, and gluteal fold was 913.3 +/- 271.7 microm, 1,018.7 +/- 305.6 microm, and 1,107.0 +/- 272.6 microm respectively. The sacral dermis was significantly thicker than the other four sites (p < 0.008), and the groin dermis was the thinnest (p < 0.039). The number of fibroblasts and fibrocytes in the sacral area and the gluteal skin folds was significantly higher than the other areas (p < 0.05). The sacral area, gluteal fold, and lateral gluteal region had relatively thicker panniculus adiposus than the abdomen and groin. The panniculus adiposus of the sacral skin was especially well developed and was comprised of several compact layers that were connected by parallel, thick collagen fibers. The authors conclude that the sacral skin is a suitable donor site for dermal grafting because its dermis has more fibroblasts and fibrocytes than the other areas studied, and its dermis is more viable and durable.

Abdomen↗
PubMed2001

Innervation of the lower eyelid in relation to blepharoplasty and midface lift: clinical observation and cadaveric study.

Ectropion or scleral show resulting from weakness of the lower eyelids is not uncommon after lower blepharoplasty or midface lift via blepharoplasty incision. Denervation of the pretarsal orbicularis oculi muscle (OOM) attributes to such complications. The authors analyzed 102 patients who underwent midface lift via lower blepharoplasty incision for the past 3 years and investigated the motor nerve innervation of the lower OOM in 20 cadavers. They encountered two cases of ectropion attributed to the denervation of the pretarsal OOM: one with dry-eye syndrome and scleral show, and the other with a "polar bear-like appearance" (i.e., outer eversion of the lower eyelid). All pretarsal and preseptal OOMs were innervated by five to seven terminal twigs of the zygomatic branches of the facial nerve that approached the muscle at a right angle. The medial portion of the lower OOM was innervated by one to two terminal twigs of the buccal branch, and the middle portion was innervated with two to three twigs of the zygomatic branch. The lateral portion was supplied by the uppermost zygomatic branch, which split into two to four twigs. The mean horizontal distance between the lateral canthus and the zygomatic branch was 2.31 +/- 0.29 cm (range, 1.7-2.7 cm) and the vertical distance was 1.20 +/- 0.20 cm (range, 0.8-1.5 cm). The critical zone was a circle with 0.5-cm radius, and its center was located 2.5 cm inferolaterally (30 deg) from the lateral canthus. It is very important to understand the motor nerve innervation of the lower eyelid and the "critical zone" to avoid postoperative ectropion or weakness of the lower eyelid resulting from paralysis of the pretarsal or preseptal OOM.

Blepharoplasty↗
PubMed2001

Patterns of oculomotor nerve distribution to the levator palpebrae superioris muscle, and correlation to temporary ptosis after blepharoplasty.

Transient diplopia, blepharoptosis, or both conditions are rare postoperative complications of blepharoplasty performed with the patient under local anesthesia. It has been hypothesized that some cases of postoperative diplopia and blepharoptosis could be attributed to the myotoxic effects of local anesthetics to the extraocular muscles and the levator muscle or to the neurotoxic effects of lidocaine. In 30 cadavers, the superior division of the oculomotor nerve was severed en bloc 1.5 cm anterior to the annulus of Zinn with the levator palpebrae superioris (LPS) and the superior rectus muscles. These muscles were detached from their origins, and their attachments to the scleral and tarsal plates were divided respectively. The specimens were treated in guanidine-hydrochloride and Alizarin Red solution, and were dissected under an operating microscope. The nerve branches of the superior division of the oculomotor nerve innervated the proximal third (type I) in 2 of 30 LPS muscles (6.7%), in 8 of 30 muscles (26.7%) extended to the middle third (type II), and reached the distal third (type III) in 20 of 30 muscles (66.7%). The terminal branches ran through the medial third (type IIIa) in 6 of 20 type III LPS muscles (30%), the central third (type IIIb) in 8 muscles(40%), and the lateral third (type IIIc) in 6 muscles (30%). The oculomotor nerve ends that extend forward to the distal third of the LPS muscle (type III) are exposed and vulnerable to local anesthetics and may be numbed during blepharoplasty. If this is so, postoperative blepharoptosis may be caused by transient paralysis of the LPS muscle, and great care should be taken during the injection of local anesthetics near the LPS.

Anesthetics, Local↗
PubMed2001

Le Fort I osteotomy with sparing fracture of lateral pterygoid plate.

This study aimed to clarify the relation between the anatomical variations of the pterygomaxillary region and fracture of the pterygoid plate during Le Fort I osteotomy. We present a secure method to separate maxillary tuberosities from pterygoid plates without injuring the pterygoid plates. Thirty specimens of hemisection of Korean skulls were used for the study. The maxilla was sectioned transversely on the floor of the pyriform aperture and posteriorly to the lateral pterygoid plate with a mechanical saw. The section was 5 to 6 mm above the tooth roots. The pterygomaxillary junction was separated with a curved osteotome in two steps: initially with light tapping of the shallow groove 2 to 3 mm anterior to the pterygomaxillary fissure at a half right angle and then changing the course of forceful tapping to more than 60 degrees. The maxillary tuberosity separated from the medial and lateral pterygoid plates during the procedure was grouped into the "disjunction group" (24 of 30, 80%) and the pterygoid plates fractured were grouped into the "fracture group" (6 of 30, 20%). The thickness of the pterygomaxillary region (T) was significantly greater in the disjunction group than in the fracture group (P = 0.034). The concavity of the pterygomaxillary fissure (C) was significantly deeper in the disjunction group than in the fracture group (P = 0.020). There was no significant difference of width of the pterygomaxillary fissure between the disjunction group and the fracture group (P = 0.169). The thin pterygomaxillary region and less concave pterygomaxillary fissure on the preoperative computed tomography scan draw precautionary attention to vulnerable pterygoid plates fractured in the procedure of Le Fort I osteotomy.

Adult↗
PubMed2001

Deep middle masseteric artery (dMMA) attributed to hemorrhage in resection of masseter muscle and mandibular angle.

This study aimed to investigate pertinent arterial supplies of masseter muscle to prevent fatal hemorrhage in resection of masseter muscle and/or mandibular angle ostectomy. Fifty-three postmortem cadavers of Koreans were used for the work. Color latex was injected into the arteries to outline 17 of 53 specimens. We found that an artery branches off the external carotid artery and enters the masseter muscle at the midpoint of its posterior margin 31 mm above the gonion. We termed this the middle masseteric artery. The middle masseteric artery is divided into superficial and deep branches. The deep branch of the middle masseteric artery travels deep in the muscle close the periosteum of the mandible in 94% of cases. The average diameter is 1.23 +/- 0.26 mm. A small artery with 1.23-mm diameter is enough to cause massive bleeding if severed. The deep branch of the middle masseteric artery is vulnerable in such procedures as resection of the masseter muscle and/or ramus and angle of the mandible.

Adult↗
PubMed2001

Reconstruction of palatal defect using mucoperiosteal hinge flap and pushback palatoplasty.

This article describes a simple, new surgical technique to provide a complete two-layer closure of palatal defect resulting from a surgical complication of trans palatal resection of skull base chordoma. The nasal layer was reconstructed with triangular shape oral mucoperiosteal turn over hinge flap based on anterior margin of palatal defect and rectangular shaped lateral nasal mucosal hinge flaps. The oral layer was reconstructed with conventional pushback V-Y advancement 2-flaps palatoplasty. Each layer of the flaps were secured with two key mattress suture for flap coaptation. This technique has some advantages: simple, short operation time, one-stage procedure, no need of osteotomy. It can close small- to medium-sized palatal defect of palate or wide cleft palate and can prevent common complication of oronasal fistula, which could be caused by tension.

Child, Preschool↗
PubMed2001

Correction of sunken and/or multiply folded upper eyelid by fascia-fat graft.

Sunken and/or multiply folded upper eyelid is one of the common, troublesome complications that can occur after Oriental blepharoplasty. In addition to orbital volume depletion, the traumatic surgical procedure of excessive fat removal might result in a varying degree of adhesion and injury to the orbital septum. Adhesiotomy followed by a restoration of volume is generally believed to be the logical way to correct such deformity. To restore volume and prevent re-adhesion, local tissues of the upper eyelid, free-fat graft, and dermis-fat graft have been used. However, local tissues are usually insufficient because of previous surgery, and the survival rate of grafted fat is often unpredictable. Moreover, the heaviness of the dermis-fat composite makes it a less than satisfactory choice. The authors value the use of free fascia-fat composite grafts for the treatment of such disfigurements. The fascia-fat composite is expected to have a better survival rate than free fat alone and to be lighter than a dermis-fat composite. In addition, the fascia-fat composite is abundant throughout the body and provides anatomical structure more similar to that of the repair site, namely, the damaged orbital septum and fat. The authors prefer the mons pubis, preauricular, and temporal areas for the donor site depending on the status of the damage. They treated 13 patients with sunken and/or multiply folded upper eyelids by fascia-fat composite grafts and obtained satisfactory results.

Adipose Tissue↗
PubMed2000

Nodular fasciitis presenting as a parotid tumour after face lifting.

Nodular fasciitis, a benign, pseudosarcomatous proliferative lesion of the soft tissue, is frequently misinterpreted as a sarcoma, both clinically and microscopically. Lesions associated with the parotid gland have been very rarely reported. We report a case of nodular fasciitis mimicking a parotid tumour after a facelift. We performed histological and immunohistochemical study and CT scan for it is difficult to make a differential diagnosis. We confirmed the final diagnosis as intraparotid nodular fasciitis. Superficial parotidectomy was performed because of initial pathological misdiagnosis reported as a dermatofibroma. The subsequent diagnosis was confirmed to be nodular fasciitis on the basis of immunohistochemical study. There was no recurrence after follow-up to 18 months. Proper diagnosis of nodular fasciitis in the parotid region and early recognition of its benign nature are necessary to differentiate it from other various benign and malignant tumours of the parotid gland.

Diagnosis, Differential↗
PubMed2000

Histomorphometry of parietal bones versus age and race.

Surgeons are used to obtaining bone grafts of calvaria, which are abundant and available. The outer table of the parietal bone can be split, usually at the level of the diploic interstice, with an osteotome. Inadvertently violating the inner table and the dura leads some surgeons to avoid using the outer table in the elderly. Sullivan and Smith measured the thickness of the outer tables, diploe, and inner table of 37 cadavers (average age, 59 years) and found each layer to be well preserved distinctly. However, they suggested that calvaria become brittle in patients older than 50 years of age. The current authors hypothesized that diploic composition is not changed, even in the elderly. The thickest part of the parietal bone of 49 Koreans and 30 whites were acquired, and undecalcified slides were made. Via light microscopy, using the National Institutes of Health image, the following measurements were made: the thickness of the parietal bone (PT), outer table (OT), diploe (DT), and inner table (IT); trabecular bone volume percent (TBV); trabecular thickness (TT); and trabecular separation (TS). There was no significant difference in the thickness of the OT, DT, and IT of the PT, TBV, TT, and TS among different ages. The PTs of women were thicker than men's. The PTs of whites were significantly thicker than Koreans'. This study disclosed that the DT is not different among varying age groups and is not sclerosed in the persons older than 80 years, and the OT of these individuals is not brittle. Thus, surgeons do not need to hesitate when taking the OT of the PT in older patients. However, the selection of the site is attentive to PT. The thickest posteromedial part of the PT is favorable and safe as a donor.

Adolescent↗
PubMed2000

Brachycephaly and external pressure.

Browsing through some literatures, I happened to find out some records on the rite of imitation of the child's head to brachycephaly. In 1976, two skulls showing extraordinary forms were excavated out of an ancient tomb at Yean village of Daedong township in Kimhae County in Kyungnam Province, the Republic of Korea. The deformation in Yean village is judged to be an intentional frontal flattening. The frontal bone of deformed individuals is remarkably flattened by a primary deforming force. The parietal bone expands laterally and superoposteriorly as a major compensatory growth. The lambdoid or occipital flattening induced by the counterforce is light and unstable. In the facial skeleton, the maxilla shifts downward as a minor compensatory growth. These findings might be substantially correspondent to the custom in the southern area of Korea in the 4th century A.D. paragraphed by Han chuan of Wei-dynasty record, History of the Three Kingdoms. It described that the people gave a pressure onto the child's forehead with stones in order to mold it for preference. Flatheaded meant "free" among the Chinook and Salish tribes of American Indians. Babies of slaves were denied the year-long beauty treatment--a board tied to the infants' padded skull--that permanently flattened the foreheads of tribal members. Referring to these records, I presume that brachycephaly can be induced by direct extrinsic pressure at least until the soft infant's head gets hard.

Culture↗
PubMed2000

Interface between titanium miniplate/screw and human calvaria.

This study demonstrates interfacial changes of titanium miniplate/screw with normal calvaria and nonvascularized calvarial bone graft ensued from craniectomy in a 53-year-old female. In 18 months after operation, a right parietal bone containing an L-shaped miniplate with screws, 5 mm long and 2 mm in external diameter, was harvested, fixed, and embedded in methylmetacrylate. Fifteen micrometer thick sections were made by an EXAKT cutting-grinding system (Exakt Company, Hamburg, Germany), and reviewed under the bright field light microscope. The mean of the bone-contacting surface ratio (BCSR) in six screwed bone was 64.1%; 69.3% in normal bone, and 60.4% in grafted bone. The trabecular bone areas in 10 x 5 mm (50 mm2) rectangular area of diploe surrounding the screws was 43.02 mm2; 45.25 mm2 in normal calvaria; and 41.82 mm2 in grafted bone. The mean Ca/P peak-height ratio of the plated and screwed calvaria was 1.47 in a 9 mm wide zone around each screw; 1.37 in normal calvaria; and 1.51 in grafted calvaria. We concede that the effect of direct contact of titanium with screws onto the bone is as much as an osseous integration (osseointegration).

Bone Plates↗