• 대한조선학회논문집
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• 제35권1호
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• pp.61-71
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• 1998

본 논문에서는 2차원 공간에서의 탄성 또는 탄소성응력파를 받는 구조부재의 동적 파괴거동을 다룬다. 이러한 문제에 대한 지배방정식은 운동방정식과 탄소성 구성방정식에 대한 증감식으로 구성된 쌍곡선 편미분 방정식으로 나타나고, 이를 풀기 위해 유한차분법을 기초로 한 Zwas방법이 도입된다. 또한 탄소성문제의 동적거동을 나타내기 위해 응력공간내 탄소성 loading path가 소성항복 현상을 모델링하는데 제안된다. 이러한 계산결과를 바탕으로 탄성체의 균열선단의 동적응력확대계수가 계산되어지고, 탄소성체에 대한 소성영역의 형상의 시간이력을 보여준다.

• Archives of Plastic Surgery
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• 제48권3호
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• pp.338-343
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• 2021

Purpura fulminans is a serious condition that can result in severe morbidity in the pediatric population. Although autologous skin grafts remain the gold standard for the coverage of partial- to full-thickness wounds, they have several limitations in pediatric patients, including the lack of planar donor sites, the risk of hemodynamic instability, and the limited graft thickness. In Singapore, an in-house skin culture laboratory has been available since 2005 for the use of cultured epithelial autografts (CEAs), especially in burn wounds. However, due to the fragility of CEAs, negative-pressure wound therapy (NPWT) dressings have been rarely used with CEAs. With several modifications, we report a successful case of NPWT applied over a CEA in an infant who sustained 30% total body surface area full-thickness wounds over the anterior abdomen, flank, and upper thigh secondary to purpura fulminans. We also describe the advantages of using NPWT dressing over a CEA, particularly in pediatric patients.

• Archives of Plastic Surgery
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• 제50권2호
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• pp.194-199
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• 2023

Moderate soft-tissue defects need stable coverage, ideally with tissue of similar characteristics and low donor site morbidity. We propose a simple technique for the coverage of moderate skin defects in the limbs. It allows intraoperative transformation of a propeller perforator flap (PPF) into a keystone design perforator flap (KDPF) in cases of unsatisfying perforator vessel or in cases of unpredictable intraoperative events. Between March 2013 and July 2019, nine patients with moderate soft-tissue defects (mean defect size 4.5 × 7.6 cm) in the limbs (two on the upper limbs and seven on the lower limbs) were covered using this technique. We performed four PPFs and five KDPFs. The mean follow-up was 5 months. There was one complication, partial distal tip necrosis in a PPF located in the leg, which healed by secondary intention within 3 weeks. The donor site was closed directly in all cases. No functional impairments were noted regardless of the perforator flap utilized. This technique enables us to employ flexible surgical strategies and allows us to make adjustments based on the patient's vascular anatomy.

• Archives of Plastic Surgery
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• 제47권2호
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• pp.135-139
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• 2020

Background This study aimed to determine the magnitude of volume reduction of the latissimus dorsi (LD) muscle after treatment using only postoperative radiotherapy (PORTx) in patients who underwent immediate breast reconstruction using an extended LD musculocutaneous (eLDMC) flap after partial mastectomy. Methods We retrospectively reviewed 28 patients who underwent partial mastectomy and an eLDMC flap, received only PORTx, and underwent chest computed tomography (CT) 7 to 10 days after surgery and 18±4 months after the end of radiotherapy, from March 2011 to June 2016. The motor nerve to the LD was resected in all patients. One plastic surgeon performed the procedures, and the follow-up period was at least 36 months (mean, 46.6 months). The author obtained LD measurements from axial CT views, and the measurements were verified by an experienced radiologist. The threshold for statistical significance was set at P<0.05. Results A statistically significant decrease in the LD volume was found after the end of PORTx (range, 61.19%-80.82%; mean, 69.04%) in comparison to the measurements obtained 7 to 10 days postoperatively (P<0.05). All cases were observed clinically for over 3 years. Conclusions The size of an eLDMC flap should be determined considering an average LD reduction of 69% after PORTx. Particular care should be taken in determining the size of an eLDMC flap if the LD is thick or if it occupies a large portion of the flap.

• Archives of Plastic Surgery
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• 제35권6호
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• pp.692-697
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• 2008

Purpose: Gluteal perforator flap has evolved to one of the standard tools for coverage of pressure sore. We used this flap to cover the defect adjacent to the buttock. Methods: From September 2004 to August 2006, gluteal perforator flaps were performed in 3 patients with sore and 9 patients with tumor. We made the rule for free style design of the flap. First, the defect should be covered fully regardless of the shape or area. Second, the location of perforators was decided to maximize flap mobility. Third, the donor-site should be closed directly. Results: Successful reconstruction was fulfilled. In 2 cases, initial flap congestion was observed but medical leech was applied and it was resolved. Partial flap loss occurred in one case. Infection was observed in one case. But there were no major complications. Conclusion: Gluteal perforator flap is very good option for the reconstruction of the defects adjacent to the buttock.

• Archives of Plastic Surgery
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• 제49권6호
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• pp.745-749
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• 2022

Background Soft tissue defects of the multiple finger present challenges to reconstruction surgeons. Here, we introduce the use of a lateral arm free flap and syndactylization for the coverage of multiple finger soft tissue defects. Methods This retrospective study was conducted based on reviews of the medical records of 13 patients with multiple soft tissue defects of fingers (n = 33) that underwent temporary syndactylization with a microvascular lateral arm flap for temporary syndactylization from January 2010 to December 2020. Surgical and functional outcomes, times of flap division, complications, and demographic data were analyzed. Results Middle fingers were most frequently affected, followed by ring and index fingers. Mean patient age was 43.58 years. The 13 patients had suffered 10 traumas, 2 thermal burns, and 1 scar contracture. Release of temporary syndactyly was performed 3 to 9 weeks after syndactylization. All flaps survived, but partial necrosis occurred in one patient, who required a local transposition flap after syndactylization release. The mean follow-up was 15.8 months. Conclusion Coverage of multiple finger defects by temporary syndactylization using a free lateral arm flap with subsequent division offers an alternative treatment option.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제36권4호
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• pp.173-177
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• 2014

The present report describe the surgical therapy, clinical course, orthodontic treatment and morphological characteristics of an adenomatoid odontogenic tumor in the maxilla of an 11-year-old patient. The cystic tumor filled the maxillary sinus and involved a tooth. Marsupialization was accompanied by partial enucleation and applied traction to the affected tooth by a fixed orthodontic appliance. Healing was uneventful and no local recurrence was observed during a 1-year period of follow-up control.

• Structural Engineering and Mechanics
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• 제32권1호
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• pp.21-36
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• 2009

An importance sampling method is presented for computing the first passage probability of elasto-plastic structures under stochastic excitations. The importance sampling distribution corresponds to shifting the mean of the excitation to an 'adapted' stochastic process whose future is determined based on information only up to the present. A stochastic control approach is adopted for designing the adapted process. The optimal control law is determined by a control potential, which satisfies the Bellman's equation, a nonlinear partial differential equation on the response state-space. Numerical results for a single-degree-of freedom elasto-plastic structure shows that the proposed method leads to significant improvement in variance reduction over importance sampling using design points reported recently.

• Archives of Plastic Surgery
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• 제36권4호
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• pp.481-484
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• 2009

Purpose: Cleidocranial dysostosis is a rare hereditary disorder affecting bones that develop by intramembranous formation. The typical features include excessive growth of transverse diameter of the skull, hypoplastic clavicles, low height and characteristic facial features. Methods: A 28 years old female patient visited by frontal area depression. The diagnosis was performed by computed tomographic study and radiographic imaging. The patient has widely opened anterior fontanelle, partial fused metopic suture, multiple wormian bone and supernumenary impacted teeth. Under the coronal incision, we exposed depressed frontal area and corrected with Medpor block carving. Results: Postoperatively, frontoparietal skull was aestheticlly improved and she was satisfied with the results. Conclusion: Authors report a case of cleiodocranial dysostosis who has been done correction of abnormal skull shape by Medpor$^{(R)}$ insertion.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.448-451
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• 2005

It was observed that after unloading or removal of the load from the specimen subjected to bending stress, partial or full elastic spring back occurred and considerable stresses have resulted while plastic deformation was considered. ABAQUS is a suite of powerful engineering simulation programs, based on the finite element method. In this paper, it was used as the main tool to analyze elastic and plastic deformations of hi-material metal joint. In the case of elastic deformations, the results were comparable to the theoretical data. Plastic deformations and residual stresses of hi-material metal joint under bending moment were obtained by ABAQUS; where the theory needs to be studied and improved further to verify the results.