• 대한족부족관절학회:학술대회논문집
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• 2008.11a
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• pp.35-36
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.916-919
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• 2004

In this paper, we proposed a new method of pre-operative planning for tibial deformity correction using double hexapod external fixator in pseudoacondroplasia. The 3-D computer graphic model of deformed tibia was reconstructed from 3 mm sliced CT data, and CAD model of double hexapod external fixator was developed. The fixator was composed of 170 mm diameter of three rings and 90 mm of twelve struts. The bone deformities and the osteotomy lines for double osteotomy were measured using X-rays, and the necessary joint values to correct the given deformities were obtained by inverse kinematics analysis. The computer graphic simulation was performed to visualize the deformity correction process and evaluate the analysis result. By examining the pre-op and post-op X-rays, the simulation result was in good agreement with the clinical outcomes.

• Journal of Korean Orthopaedic Sports Medicine
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• v.8 no.2
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• pp.115-120
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• 2009

Purpose: To evaluate the outcomes of three different surgical approaches in treating a distal radius fracture with dorsal communition. Materials and Methods: From April, 2006 to May, 2009, 49 patients over age of 60years old with unstable dorsal communition distal radius fracture were analyzed. We compared maintainability of reduction by radiological follow-up observations and clinical outcomes using Mayo wrist scores. One-Way ANOVA test was performed to examine the statistical correlation between the methods. Results: All three approaches provided satisfactory post-op reduction results. However, follow-up observations showed significant loss of reduction in the external fixation only group compared to the added bone graft group and the volar anatomical locking plate group (P<0.05). Mayo wrist score was indifferent between the three groups. Conclusion: Treatment of a distal radius fracture with severe dorsal communition using an external fixation only appears to be insufficient in maintaining reduction of a cancellous bone defect.

• 전기의세계
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• v.42 no.10
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• pp.25-31
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• 1993

마이크로 장치에 관한 연구를 통하여 개발될 설계 및 제자 기술들은 차후 마이크로 펌프외에도 여러가지 마이크로 센서나 기계요소를 제작하는 데 유효 적절하게 사용될 수 있는 기술들로서, 국내에서도 마이크로머시닝 기반 기술의 노우하우가 축적되어야 한다. 마이크로 펌프는 미세 유량 제어장치, 미생물 조작 장치 등의 제작을 가능하게 하여 고정밀을 요하는 측정 계기와 장치, 치료기구 등에의 응용성이 다양하다. 이로 인하여 공학 및 과학, 의학 분야의 발전에 공헌이 크리라 기대된다.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.531-536
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• 2004

In fracture treatment with external fixators, the inter-fragmentary movements at the fracture site affect the fracture healing process, and these movements are highly related to the stiffness of external fixation systems. Therefore, in order to provide the optimal fracture healing at the fracture site, it is essential to understand the relationship between the stiffness and the system configurations in external fixation system. In this study we investigated the influences of system configuration parameters on the stiffness in the finite element analysis of an external fixation system of a long bone. The system alignment, the geometric and the material non-linearity of the pin, the joint stiffness and the callus formation were considered in the finite element model. In the first, the system stiffness of the developed finite element model was compared with the experiment data for model validation. The consideration of the joint stiffness and nonlinearity of the model improved the system stiffness results. The joint stiffness, the non-alignment of the system decreased the system stiffness while the callus formation increased the system stiffness. The present results provided the biomechanical basis of rational guidelines for design improvements of external fixators and pre-op. planning to maximize the system stiffness in fracture surgery.

• Journal of Korean Foot and Ankle Society
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• v.8 no.2
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• pp.182-190
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• 2004

Purpose: To evaluate the clinical feature and the results of the treatment of Lisfranc joint fracture/dislocation with limited open reduction, pin fixation and Ilizarov external fixation. Materials and Methods: From June 2001 to May 2003, six patients with Lisfranc fracture/dislocation were treated. The average periods of follow-up was 23 months. After limited open reduction on the second tarso-metatarsal joint, we performed pin fixation of the above joint. On the other Lisfranc joint fracture/dislocation, closed reduction and the application of Ilizarov external fixator was done. This rigid system produced the early partial weight bearing and joint motion of the injured foot and ankle joint. The parameters used were radiographic evaluation, patient's clinical assesment and the AOFAS midfoot score. Results: We used the Myerson's criterier to evaluate the radiographic result. All cases could be achieved more than nearly anatomical reduction. Three cases of excellent and 3 cases of good result could be obtained in the evaluation of the patient's clinical assesment. The average AOFAS midfoot score was 87.2 ($76{\sim}95$) points. Conclusion: The treatment using Ilizarov external fixation on Lisfranc joint fracture/dislocation can be another useful method.

• Journal of the Korean Orthopaedic Association
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• v.55 no.3
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• pp.193-199
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• 2020

A gamma nail has been used to treat intertrochanteric fractures since 1988. Although such cephalomedullary nails have mechanical advantages over extramedullary fixation devices, such as sliding hip screw, their beneficial effects on treating the Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) 31-A1 and 31-A2 fractures are still controversial. During their 30-year history, many problems have been overcome, and new types of cephalomedullary nails have been introduced in clinical practice. New cephalomedullary nail systems facilitate nailing procedures and enhance the purchase capability of the femoral head by a lag screw. On the other hand, the failure rate still depends on the hands of the orthopedic surgeons. This review article focused on the basic principle of medial support and restoration of a medial buttress during the treatment of trochanteric fractures using a cephalomedullary nail.

• Radiation Oncology Journal
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• v.16 no.2
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• pp.167-175
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• 1998

Purpose : It is not a simple task to achieve the ideal isodose curve with a standard vaginal applicator or sing1e plane needle impant in the paravaginal tissue when primary or recurrent gynecological neoplasms(cervical cancers, vaginal cancers and vulvar cancers) are treated as a boost following external beam radiotherapy. The authors introduce the development and construction of a simple, inexpensive, customized applicator for volume implant to maximize the radiation dose to the tumor while minimizing the dose to the rectum and the bladder. Materials and Methods : Nine patients underwent Ir-192 transperineal interstitial implantation for either recurrent(5 cases) or primary(3 cases) cervical cancers or primary vaginal cancer(1 case) between August 1994 and February 1998 at Ajou university hospital. First 3 cases were performed with a sing1e plane implant guided by digital palpation. Because of inadequate isodose coverage in the tumor volume in first 3 cases, we designed and constructed interstitial vaginal applicator for volume implant to improve tumor dose distribution and homogeneity while sparing the surrounding normal tissue. Our applicators consist of vaginal obturator and perineal template that made of the clear acrylamide and dental mold material$(Provil^{(R)})$. The applicators were customized individually according to the tumor size and its location Both HDR and LDR irradiation were given with these applicators accomodating 6 Fr needles(Microselectron Nucletron). The pretreatment planning prior to actual implant was performed whenever possible. Results : Needles can be inserted easily and evenly into the tumor volume through the holes of templates, requiring less efforts and time for the implant procedure. Our applicators made of materials available from commercial vendors. These have an advantage that require easy procedure, and spend relatively short time to construct. Also it was possible to fabricate applicators to individualize according to the tumor size and its location and to achieve the ideal isodose coverage. We found an accurate needle arrangement and ideal dose distribution through the CT scan that was obtained in 3 cases after needle implant. Three patients with primary cervical and vaginal cancers were controlled locally at final follow up. But all recurrent cases failed to do so. Conclusion : The authors introduce inexpensive, simple interstitial vaginal templates which were self-designed and constructed using materials available from commercial vendors such as acrylanide and dental mold material $(Provil^{(R)})$.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.10a
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• pp.15-15
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• 2003

치과재료에 사용되는 금속재료는 주로 스테인리스강, 타이타늄, Ni-Ti, Co-Cr등과 같은 특수합금이 주로 사용되고 있다. 이들 재료는 치과 보철물과 교정재료 및 충전재료로 주로 사용되고 있으며 그 외 치과에서 사용되는 기기나 기구에도 많이 활용되고 있다. 특히 치과 보철물을 사용하여 치료를 원하는 환자가 최근에 급격히 증가하면서 임플란트 고정체와 나사 등을 이용한 치료법의 연구와 개발이 필요하게 되어 세계적으로 연구와 투자가 활발히 진행되고 있다. 그러나 재료의 설계나 합금의 설계 및 제품의 설계상의 문제로 인하여 생체조직과 결합하는데 많은 문제점이 임상적으로 발생되고 있다. 즉 임플란트 표면의 생체적합성부여, 고정체와의 결합시 파절이나 풀림현상, 골에 고정체로 사용하는 나사의 강도와 내마모성문제 등이 개선되어야 할 문제점으로 남아있다. 또한 총의치에 사용되는 자석 어태치먼트의erosion-corrosion문제, 교정선의 탄성 과 마모저항문제 등은 앞으로 계속적인 연구를 행하여야할 과제로 남아있다. 또한 국소의치에서 사용되는 frame은 정밀주조법을 통하여 제조하며 주조상의 결함 등으로 인한 클라스프의 파절 문제점이 발생되고 있다. 따라서 본 연구에서는 치과재료로 사용되는 임플란트 고정체, 나사, 교정용 선등의 문제점을 고찰하고, 지금까지 이루어진 연구를 중심으로 최적의 개선 조건을 찾고자하였다. 최근첨단소재 및 금속재료를 사용하여 치과재료 합금을 설계할 수 있는 연구가 활발히 진행된다면 수입에 의존하고 있는 고가의 치과재료를 값이 싼 고성능의 제품으로 대체할 수 있는 효과가 클 것으로 생각된다.>$\rho$$\sub$0/=1.8 %. As t$\sub$Co/ increases, a transition from the regime of co-existence of superparamagnetic and ferromagnetic behaviors to ferromagnetic behavior was observed. Tunneling barrier called "decay length for tunneling" for the films having the thickness of Co layer from 1.4 to 1.6 nm was measured to be ranged from 0.004 to 0.021 ${\AA}$$\^$-1/.문에 기업간 관계를 연구하는 측면에서는 탐험적 연구성격이 강하다. 더 나아가 본 산업의 주된 연구가 질적이고 기업내부만을 연구했던 것에 비교하면 시초적이라고 할 수 있다. 또한 관계마케팅, CRM 등의 이론적 배경이 되고 있는 신뢰와 결속의 중요성이 재확인하는 결과도 의의라고 할 수 있다. 그리고 신뢰는 양사 간의 상호관계에서 조성될 수 있는 특성을 가진 반면, 결속은 계약관계 초기단계에서 성문화하고 규정화 할 수 있는 변수의 성격이 강하다고 할 수가 있다. 본 연구는 복잡한 기업간 관계를 지나치게 협력적 측면에서만 규명했기 때문에 많은 측면을 간과할 가능성이 있다. 또한 방법론적으로 일방향의 시각만을 고려했고, 횡단적 조사를 통하고 국내의 한 서비스제공업체와 관련이 있는 컨텐츠 공급파트너

• Journal of the Korean Arthroscopy Society
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• v.4 no.2
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• pp.148-153
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• 2000

Purpose : This study was conducted to analyze the results of arthroscopic ankle arthrodesis and to verify the advantages of the technique compared to open ankle arthrodesis. Materials and Methods : Between October 1992 and August 1996, the arthroscopic ankle arthrodesis had been performed in five patients(six ankle joints): two patients with seropositive rheumatoid arthritis(one patient surgically treated bilaterally), two with osteoarthritis and one with tuberculous arthritis. There were one man and 4 women. Average age was 48 years ranging from 38 to 65 years. Follow up period was average 45 months(range, $12\~80$). Results : All patients were successfully treated with ankle joint arthrodesis under arthroscopic control. The mean time to fusion was 10 weeks(range, $6\~15$). There was a $100\%$ fusion rate without any complication. Conclusion : The arthroscopic ankle arthrodesis was successful in all cases with less morbidity and short hospital stay. It was technically feasible with excellent predictability.