• Archives of Plastic Surgery
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• v.37 no.4
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• pp.385-390
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• 2010

Purpose: The purpose of this study is to demonstrate the usefulness of the high resolutional ultrasonographic features in patients with foreign body. Methods: From September 2007 to August 2009, we retrospectively reviewed high resolutional ultrasonogram using 5~12 MHz linear transducer of 13 patients presenting with inflammation after foreign body injection. They were referred for complications after foreign body injection. Injected foreign bodies were 4 silicone, 4 paraffin, 2 artecoll, and 3 unknown. We treated them with foreign body removal (7), foreign body removal and corrective plastic surgery (4), and conservative treatment with antibiotics and steroid injection (2). Results: High resolutional ultrasonography well demonstrated the existence of foreign body and it's overall size, location within the tissue layer, and vascularity. Comparison between preoperative and postoperative ultrasonographic findings was useful not only to evaluate the prognosis but also to plan the treatment. These ultrasonographic findings aided in precise assessment of the contour and location of the foreign body and led to an accurate surgery. We were able to acquire various information in order to set a detailed plan for the operation which in turn, led to a precise, successful surgery. After the treatment, complication did not occur in 12 patients, except 1 patient. But this patient was also treated after reoperation. Postoperative high resolutional ultrasonography shows almost foreign body removed and inflammation disappeared. Conclusion: Considering the usefulness of highresolution ultrasonography in foreign body injection, highresolution ultrasonography would be necessary for both the patient and the doctor. Preoperative and postoperative high resolutional ultrasonography is highly accurate, safe, inexpensive and easy. It can be a useful modality in foreign body after plastic surgery.

• Archives of Plastic Surgery
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• v.44 no.5
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• pp.370-377
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• 2017

Background Composite grafts are frequently used for facial reconstruction. However, the unpredictability of the results and difficulties with large defects are disadvantages. Adipose-derived stem cells (ADSCs) express several cytokines, and increase the survival of random flaps and fat grafts owing to their angiogenic potential. Methods This study investigated composite graft survival after ADSC injection. Circular chondrocutaneous composite tissues, 2 cm in diameter, from 15 New Zealand white rabbits were used. Thirty ears were randomly divided into 3 groups. In the experimental groups (1 and 2), ADSCs were subcutaneously injected 7 days and immediately before the operation, respectively. Similarly, phosphate-buffered saline was injected in the control group just before surgery in the same manner as in group 2. In all groups, chondrocutaneous composite tissue was elevated, rotated 90 degrees, and repaired in its original position. Skin flow was assessed using laser Doppler 1, 3, 6, 9, and 12 days after surgery. At 1 and 12 days after surgery, the viable area was assessed using digital photography; the rabbits were euthanized, and immunohistochemical staining for CD31 was performed to assess neovascularization. Results The survival of composite grafts increased significantly with the injection of ADSCs (P<0.05). ADSC injection significantly improved neovascularization based on anti-CD31 immunohistochemical analysis and vascular endothelial growth factor expression (P<0.05) in both group 1 and group 2 compared to the control group. No statistically significant differences in graft survival, anti-CD31 neovascularization, or microcirculation were found between groups 1 and 2. Conclusions Treatment with ADSCs improved the composite graft survival, as confirmed by the survival area and histological evaluation. The differences according to the injection timing were not significant.

• Archives of Plastic Surgery
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• v.40 no.5
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• pp.597-602
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• 2013

Background The forehead, which occupies about one third of the face, is one of the major determinants of a feminine or masculine look. Various methods have been used for the augmentation of the forehead using autologous fat grafts or alloplastic materials. Methylmethacrylate (MMA) is the most appropriate material for augmentation of the forehead, and we have used an injection-molding technique with MMA to achieve satisfactory results. Methods Under local anesthesia with intravenous (IV) sedation, an incision was made on the scalp and a meticulous and delicate subperiosteal dissection was then performed. MMA monomers and polymers were mixed, the dough was injected into the space created, and manual molding was performed along with direct inspection. This surgery was indicated for patients who wanted to correct an unattractive appearance by forehead augmentation. Every patient in this study visited our clinics 3 months after surgery to evaluate the results. We judged the postoperative results in terms of re-operation rates caused by the dissatisfaction of the patients and complications. Results During a 13-year period, 516 patients underwent forehead augmentation with MMA. With the injection-molding technique, the inner surface of the MMA implant is positioned close to the underlying frontal bone, which minimizes the gap between the implant and bone. The borders of the implant should be tapered sufficiently until no longer palpable or visible. Only 28 patients (5.4%) underwent a re-operation due to an undesirable postoperative appearance. Conclusions The injection-molding technique using MMA is a simple, safe, and ideal method for the augmentation of the forehead.

• Archives of Plastic Surgery
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• v.37 no.3
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• pp.233-238
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• 2010

Purpose: As the use of soft tissue fillers becomes more popular, complications such as foreign body granuloma (FBG) are increasing. We report 120 cases of facial FBG and review the available literatures. Methods: 120 patients of facial FBG in our clinic from Mar. 2003 to Feb. 2008 were complied and analyzed. A retrospective chart review was done and patient satisfaction was evaluated with a questionnaire using 5 score scale. Patients with severe inflammation sign or bizarre deformity underwent surgical excision and those with minimal symptoms or a history of hyaluronic acid injection received injection therapy using hyaluronidase. Results: 100 females and 20 males were observed. The average age was 43.7 years (from 16 to 74). 84 patients received surgical therapy and 36, injection therapy. Deformity of facial contour, foreign body sensation and inflammation sign were the three main chief complaints. 84 patients did not know what the injection materials were. The known materials are as follows: collagen, hyaluronic acid, silicone oil, paraffin. 92 cases were performed by unlicensed practitioners, 29 by physicians. Anatomical site most frequently affected by the foreign body granuloma was the cheek (25.8%), followed by forehead (19.2%), lips (15.8%), nose (9.2%), mentum (8.3%), eyelid and eyebrow (4.3%) and temple (0.8%). In 21 patients (17.5%), FBGs were found on multiple sites. Patients with inflammation sign got the highest satisfaction ($3.19{\pm}0.73$) (p=0.001) among 3 chief complaints. And patient satisfaction was statistically higher in surgical therapy group ($3.43{\pm}0.72$) than in injection therapy group ($2.97{\pm}0.88$) (p=0.003). Conclusion: We suggest that it may be beneficial to tailor the type of treatment for FBG relying on wound state and patient's chief complaints. In surgical therapy, resolute approach is necessary to correct facial deformity definitely and to minimize inflammation. Injection therapy could be another option for those with minimal symptoms or a history of hyaluronic acid injection. To prevent foreign body granuloma, not only plastic surgeons but also other physicians should inject soft tissue fillers with great caution and we should warn the public of disastrous consequences associated with illegal medical practice.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.183-185
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• 1998

In this paper, a magnetic circuit of plastic magnet roller for laser printer is presented. The magnetization direction of plastic magnet is decided by the flux distribution of injection mold during the manufacturing process. The injection mold is designed and analysed to fit the design specification. The experiment showed that the flux distribution of a magnet is good agreement of the given specification.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.217-220
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• 2003

Due to the lighter weight and the higher freedom of design than metals plastics have been spot lighted in a wide number of applications. In the making plastic parts injection-molding process is one of the most general methods. During the injection molding process, filling-packing-cooling process, plastics have exposed to several external stresses and then plastic parts injected have molding effects which are known as anisotropic properties, orientation, and residual stress. Those molding effects are often shown as unexpected phenomena which are warpage, strength decrease, stiffness reduction, etc. In case of glass fiber filed plastics these effects are more significant than the ufilled ones. Therefore the molding effects have to be considered in the parts design using glass fiber reinforced plastics. We have developed the interface program in order to consider the molding effects in structural analyses of plastic parts using Heirarchical structural searching and layer handling in direction of thickness algorithm. The advantages of this program are the freedom of FE mesh between molding and structural analysis, the variable layer to the thickness direction of parts and the conveniences of data transferring and checking

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.8-13
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• 2015

In this study, we fabricated and characterized a nanostructured surface based on a plastic injection molding with a local mold heating (LMH) system. A metal mold core with a closed packed nano convex array (CVA) was achieved by integrated engineering procedures: (1) master template fabrication by anodic aluminum oxidation (AAO), (2) nickel electroforming (NE) process, and (3) post-processing by precision machining. The nickel mold core was utilized to replicate a surface with a closed packed nano concave-array (CCA) based on injection molding using cyclic olefin copolymer (COC) as a plastic material. In particular, an LMH system was introduced to enhance transcription quality of the nano structures by delaying solidification of molten polymer near the surface of the mold core.

• Archives of Plastic Surgery
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• v.48 no.1
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• pp.10-14
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• 2021

Soft tissue filler injections are widely used due to their immediate effects, predictable results, and high stability. However, as the use of soft tissue filler injections has increased, various complications have been reported. We report a life-threatening complication in a patient who developed sepsis and necrotizing fasciitis. A 45-year-old woman presented with right leg pain and discharge from the labia majora. The patient had received a soft tissue filler injection of unknown composition 1 year earlier and had recently undergone incision and drainage for an inflammatory cystic nodule. Antibiotic treatment was administered for cellulitis, but the infection progressed to necrotizing fasciitis and sepsis. Fasciotomy and intensive care unit treatment improved the systemic infection, but the soft tissue filler injection site did not respond to treatment for 1 month. Thus, the injection site was covered with a pedicled vertical rectus abdominis musculocutaneous flap after wide excision. The area of skin necrosis on the leg was covered with split-thickness skin grafts. Infections occurring after soft tissue filler injections are related to biofilms, and treatment is sometimes difficult. Therefore, although soft tissue filler injections have a favorable safety profile, it is important to be aware of the risk of life-threatening complications.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1206-1209
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• 2005

In recent, injection molding process for features in sub-micron scale is under active development as patterning nano-scale features, which can provide the master or stamp for molding, and becomes available around the world. Injection molding has been one of the most efficient processes for mass production of the plastic product, and this process is already applied to nano-technology products successfully such as optical storage media like DVD or BD which is a large area plastic thin substrate with nano-scale features on its surface. Bio chip for like DNA sequencing may be another application of this plastic substrate. The DNA can be sequenced using order of 100 nm pore structure when making the DNA flow through the pore structure. Agarose gel and silicon based chip have been used to sequence the DNA, but injection molded plastic chip may have benefit in terms of cost. This plastic DNA sequencing chip has plenty of pillars in order of 100 nm in diameter on the substrate. When the usual features in case of DVD or BD have very low aspect ratio, even less than 0.5, but the DNA chip will have relatively high aspect ratio of about 2. It is not easy to injection mold the large area thin substrate with sub-micron features on its surface due to the characteristics of the molding process and it becomes much more difficult when the aspect ratio of the features becomes high. We investigated the effect of the molding parameters for injection molding with high aspect ratio nano-scale features and injection molded some plastic DNA sequencing chips. We also fabricated PR masters and Ni stamps of the DNA chip to be used for molding

• IE interfaces
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• v.15 no.3
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• pp.263-269
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• 2002

The injection molding process is a one of the most efficient techniques for manufacturing plastic parts of complex shape at low cost. In injection molding, molten plastic material is injected into the mold and cooled. Selection of molding conditions greatly affects the quality of molded parts. In this case study, we attempted to optimize the injection molding condition for a cooling filter using Taguchi experimental design methodology. The injection molding experiments were carried out using the Moldflow simulation software.