Eun Sang Dhong

Vascular complications of hyaluronic acid fillers and the role of hyaluronidase in management

Skin necrosis following the inadvertent arterial injection of hyaluronic acid (HA) is a serious complication. It is not clear whether or not subcutaneous injections of hyaluronidase decrease skin necrosis in HA-induced vascular complications. We had four cases of HA-induced vascular complications, two of which were treated with hyaluronidase the next day. All of the patients had skin necrosis and scarring. We performed an animal study with rabbit ears in which HA filler was injected into the auricular arteries of both ears. Five rabbits each received a subcutaneous injection of 750 IU of hyaluronidase 4 and 24 h after the filler injection. The hyaluronidase-treated ears in the 4-h intervention group had significantly smaller necrotic areas (p<0.05), while the 24-h intervention group had no differences in the area of necrosis. Hyaluronidase reduced the vascular complications of HA fillers when used early, but there was no benefit to hyaluronidase injection after 24 h.

Correlation of high-resolution ultrasonographic findings with the clinical symptoms and electrodiagnostic data in carpal tunnel syndrome

There are several different imaging methods that are helpful in the diagnosis of carpal tunnel syndrome, including traditional radiography, computed tomography (CT), and magnetic resonance imaging (MRI). CT and MRI offer the advantage of providing direct visualization of the structural abnormality of the carpal tunnel and median nerve, but both of these modalities are expensive and time-consuming. Recently, high-resolution ultrasonography has been reported to be effective in the study of the musculoskeletal system. The authors designed a case–control study to assess the diagnostic value of high-resolution ultrasonography. Forty-eight patients, for a total of 96 hands, whose diagnosis was confirmed by self-administered questionnaire and electrodiagnostic tests, underwent high-resolution ultrasonographic studies. The authors compared the sonographic findings with the electromyographic data and the patients’ severity scores on the self-questionnaires. Proximal swelling of the median nerve at the entrance to the carpal tunnel was found to correlate with the nerve conduction data. Also, compression of the median nerve under the transverse carpal ligament was found to correlate with the subjective symptoms. Although ultrasonography is not an ideal method of diagnosis for carpal tunnel syndrome, it may be helpful for estimating the symptom severity and nerve conduction deficit.

Postoperative morphologic analysis of carpal tunnel syndrome using high-resolution ultrasonography.

The authors evaluated the morphologic changes that follow division of the transverse carpal ligament in patients with carpal tunnel syndrome (CTS) using high-resolution ultrasonography. Ten patients, for a total of 20 hands, underwent high-resolution ultrasonographic studies before the operation and 8 months after the operation. They were all diagnosed with bilateral idiopathic CTS. The authors evaluated the configuration of the median nerve and carpal tunnel at 3 different levels of the wrist: the distal radiocarpal joint level, the pisiform level, and the hook of hamate level. The median nerve gained in thickness to a remarkable extent at 2 distal levels after the operation. The change in morphology of the carpal tunnel at these 2 distal levels was obvious, but the cross-sectional area of the carpal tunnel was increased significantly only at the hook of hamate level. The transverse diameters of the carpal tunnel were not significantly changed. As mentioned, the authors found that the median nerve gained significantly in volume at the distal part of the carpal tunnel postoperatively, and the volumetric increase in the carpal tunnel appears to have resulted from an anterior displacement of newly formed transverse carpal ligament, rather than from a widening of the bony carpal arch.

In Vivo Evaluation of Mixtures of Uncultured Freshly Isolated Adipose-Derived Stem Cells and Demineralized Bone Matrix for Bone Regeneration in a Rat Critically Sized Calvarial Defect Model

Although many studies have suggested that human adipose tissue contains pluripotent stem cells, a few reports are available on stromal vascular fraction (SVF). In the present study, we evaluated the bone formation capacities of SVF. We implanted uncultured freshly isolated adipose-derived stem cells combined with demineralized bone matrix (DBM) to induce bone regeneration in a critically sized rat calvarial defect model. We used DBM (DBX(®)) and/or poly(70L-lactide-co-30DL-lactide) copolymer PLA as a scaffold. Fifty white rats were randomized to 5 different groups (n=10): (1) control, (2) DBM, (3) DBMu2009+u2009SVF, (4) DBM + PLA, and (5) DBM + PLAu2009+u2009SVF groups. After acquiring SVF, an 8-mm critically sized calvarial defect was made in each rat. Specimens were harvested at 8 weeks postimplantation and evaluated radiographically and histologically. New bone formation was qualified by hematoxylin and eosin staining and anti-osteocalcin antibody (OC4-30) immunostaining of calvarial sections. Amounts of mineralization were determined by radiodensitometric analysis. In gross appearance, the DBM +u2009SVF and DBM + PLA +u2009SVF groups showed more abundant bone formation than the other groups. Radiodensitometric evaluations revealed that significant intergroup differences were observed according to the Kruskal-Wallis (rank) test (P=0.030<0.05). The 5 groups show different amounts of filling of bone defects (control: 13.48%; DBM: 39.94%; DBM +u2009SVF: 57.69%; DBM + PLA: 24.86%; DBM + PLA +u2009SVF: 42.75%). Histological evaluation revealed that there was abundant new bone formation in the DBM +u2009SVF and DBM + PLA +u2009SVF groups. It was found that undifferentiated adipose-derived stem cells in the form of SVF induced new bone formation in rat calvarial defects. Accordingly, SVF offers a practical, promising candidate for regenerative tissue engineering or cell-based therapy.

Correlation of electrodiagnostic findings with subjective symptoms in carpal tunnel syndrome

&NA; The records of 138 patients (222 hands) who had been evaluated by preoperative nerve conduction study (NCS) and consecutive self‐administered questionnaires were analyzed to determine diagnostic relations in carpal tunnel syndrome. Hands were categorized into six grades (extreme, severe, moderate, mild, minimal, and negative) according to the three modalities: the NCS data of the median sensory nerve, Symptom Severity Scale score, and Functional Status Scale score. The authors evaluated the correlation, independence, homogeneity, and association among parameters, and found the following: (1) the NCS data correlated more significantly (p < 0.05) and was associated more linearly with Symptom Severity Scale score than the Functional Status Scale score; (2) the choice of modality exerted an influence on grading severities, thus grades varied according to the modalities; and (3) the distribution of patients was not homogenous; there were more extremes in NCS, and more severe scores on the Symptom Severity Scale. Patients rated as one homogeneous severity by NCS data may be interpreted into different severities (from negative to extreme) by self‐administered questionnaires and vice versa. Dhong ES, Han SK, Lee Bl, Kim WK. Correlation of electrodiagnostic findings with subjective symptoms in carpal tunnel syndrome. Ann Plast Surg 2000;45:127‐131

The effects of the number and ratio of repaired arteries and veins on the survival rate in digital replantation.

&NA; From January 1990 to December 1998, 631 consecutive single‐digit replantations were reviewed retrospectively to determine the essential number of vascular anastomoses and the artery‐to‐vein ratio for successful finger replantation. The correlations between the number and the ratio of anastomosed vessels and the survival rate were examined according to the amputated digital levels, and all of the correlated results were compared with each other statistically. In zone I, the survival rate of the digits with a vein repaired was higher than that of digits treated with the external bleeding method. In zone II, repairing more arteries than veins led to venous congestion and resulted in a failure of replantation. Thus, the ratio of an equal or greater number of veins repaired to the arteries repaired was an important factor in successful replantation in zone II, which may be due to the large amount of arterial imput relative to the small volume of venous drainage via small veins in the replanted digit. In zone III, the equal number of arteries and veins repaired was also an important factor in successful replantation. However, unlike zone II, even when more arteries were repaired than veins, venous congestion occurred rarely because the vein in this area was larger, providing sufficient venous drainage. In zone IV, repair of two veins was needed to yield good results. Because the volume of the amputated part in zone IV was larger than in other zones, it was desirable to repair both arteries, even though repairing one artery yielded good results. In conclusion, it is desirable to repair as many vessels as possible to increase the possibility of a good result. However, digital amputations and their conditions for replantation differ. Therefore, the number and ratio of vessels that need to be repaired should be modified and adjusted in each case. Lee B‐I, Chung H‐Y, Kim W‐K, Kim S‐W, Dhong E‐S. The effects of the number and ratio of repaired arteries and veins on the survival rate in digital replantation. Ann Plast Surg 2000;44:288‐294

Facial Soft Tissue Augmentation using Autologous Fat Mixed with Stromal Vascular Fraction

Background Autologous fat grafting evolved over the twentieth century to become a quick, safe, and reliable method for restoring volume. However, autologous fat grafts have some problems including uncertain viability of the grafted fat and a low rate of graft survival. To overcome the problems associated with autologous fat grafts, we used uncultured adipose tissue-derived stromal cell (stromal vascular fraction, SVF) assisted autologous fat grafting. Thus, the purpose of this study was to evaluate the effect of SVF in a clinical trial. Methods SVF cells were freshly isolated from half of the aspirated fat and were used in combination with the other half of the aspirated fat during the procedure. Between March 2007 and February 2008, a total of 9 SVF-assisted fat grafts were performed in 9 patients. The patients were followed for 12 weeks after treatment. Data collected at each follow-up visit included clinical examination of the graft site(s), photographs for historical comparison, and information from a patient questionnaire that measured the outcomes from the patient perspective. The photographs were evaluated by medical professionals. Results Scores of the left facial area grafted with adipose tissue mixed with SVF cells were significantly higher compared with those of the right facial area grafted with adipose tissue without SVF cells. There was no significant adverse effect. Conclusions The subjective patient satisfaction survey and surgeon survey showed that SVF-assisted fat grafting was a surgical procedure with superior results.

Enhancement of bone regeneration using osteogenic-induced adipose-derived stem cells combined with demineralized bone matrix in a rat critically-sized calvarial defect model.

INTRODUCTIONnHuman adipose tissue contains pluripotent stem cells that are similar to bone marrow-derived stem cells. The present study examined whether osteogenic induced adipose-derived stem cells (ASCs) could enhance the osteogenic capacity of demineralized bone matrix and accelerate bone formation in a rat critically-sized calvarial defect model.nnnMATERIALS AND METHODSnForty Sprague-Dawley rats were divided randomly into four groups containing 10 rats per each group (Control, 0.05 cc fibrin glue (25 mg/ml) and 0.05 cc thrombin (130 U/ml); DBX, control + 0.2 g DBX�; ASC, DBX + 1 x 105 ASCs/g; iASC, DBX + 1 x 105 osteogenic-induced ASCs/g). After osteogenic differentiation of ASCs, alkaline phosphatase and von Kossa staining were performed each week to determine the extent of differentiation and mineralization. An 8-mm critical size circular defect was made in the calvarial bone of each rat. The specimens were harvested 8 weeks after implantation, and radiographic and histological evaluations were carried out. New bone formation was quantified by radiodensitometric analysis of the calvarial sections. Statistical analysis was accomplished using a Mann-Whitney test and Kruskal-Wallis test at a significance level of P < 0.05.nnnRESULTSnAlkaline phosphatase and von Kossa staining showed that the osteogenic-induced ASCs yielded higher osteogenic differentiation at 3 weeks. The calvarial defect was filled more in the iASC group compared to the other groups, as demonstrated by the gross appearance of the specimen and radiologic evaluation. The mean radiodensity of the control, DBX, ASC, and iASC group was 16.78%, 39.94%, 25.58%, and 51.31%, respectively, and these were significantly different (P=0.034). Histomorphological evaluation confirmed that new bone formation was accelerated and enhanced by the osteogenic-induced ASCs.nnnCONCLUSIONSnASCs produced greater osteogenic differentiation at 3 weeks. Osteogenic regeneration was accelerated and enhanced in vivo with the osteogenic-induced ASCs, compared to undifferentiated ASCs. Osteogenic-induced ASCs are an excellent and promising candidate for regenerative medicine and tissue engineering application.

Transplantation of Adipose Derived Stem Cells for Peripheral Nerve Regeneration in Sciatic Nerve Defects of the Rat

Tissue engineering approaches for promoting the repair of peripheral nerve injuries have focused on cell-based therapies involving Adipose-derived stem cells (ASCs). The authors evaluated the effects of undifferentiated ASCs and of neurally differentiated ASCs on the regenerating abilities of peripheral nerves. We hope that this would demonstrate the feasibility of using adipose derived stem cells for peripheral nerve regeneration and provide clues regarding the use of adipose- derived stem cells. ASCs were isolated and cultured. Then the cells were cultured with neuronal induction agents for neural differentiation. ASCs and neurally differentiated ASCs were transplanted into sciatic nerve defects. After 12 weeks, the number and diameter of the myelinated fibers were measured and nerve conduction study was done. The extent of regeneration of myelinated fibers in the neurally differentiated ASCs transplanted group was greater than that in the ASCs transplanted group or the control group. However, thickness of myelin sheath and diameter of nerve fibers in the ASCs transplanted group were greater than those in the neutrally differentiated ASCs transplanted group or the control group. Nerve conduction study showed good recovery in the neurally differentiated ASCs transplanted groups. Muscles can atrophy and contract if denervation has started. It would be difficult to recover muscle function even if the nerve was reinnervated. Therefore, although neurally differentiated ASCs were found to have a greater functional effect than non-differentiated ASCs, time constraint is important when considering a method of ASCs transplantation.

Photogrammetric facial analysis of attractive Korean entertainers

BackgroundThe authors have developed a new digital photogrammetric method of facial analysis known as balanced angular and proportional analysis (BAPA). Using BAPA, the authors analyzed the faces of attractive Korean entertainers.MethodsThe BAPA approach involves 28 landmarks and 14 measurements (10 proportional and 4 angular measures). Standardized mean angular values of famous entertainers are referred to as recommended aesthetic mean angles (RAMA) and the mean proportional values as the recommended aesthetic mean proportions (RAMP). In this study, 30 frontal views of famous Korean entertainers (15 men and 15 women) were collected from Internet Web pages, and the data analyzed using V-ceph. A t test (with the significance level set at a p value of 0.05) was performed to analyze male versus female comparisons.ResultsSignificant between-group differences (pxa0<xa00.05) were found for P-lower face, P-eye height, P-lip, P-interangle, and the mandibular contour in the frontal views. Famous Korean female entertainers differ from famous male entertainers. The women have a shorter lower face, larger eyes, smaller lips, and a more slender and oval shape of the mandibular soft tissue contour.ConclusionsThe authors insist that facial analysis should take into consideration racial, ethnic, and gender differences. The BAPA approach is a new practical and simple method for photogrammetric facial analysis. Using the authors’ method, more advanced and automated computer systems for analyzing human faces may be developed.