시스템 구성 인자를 고려한 외고정장치 시스템의 강성 해석

김윤혁,이현근,Kim Yoon Hyuk,Lee Hyun Keun 대한의용생체공학회 2004 의공학회지 Vol.25 No.6

외고정장치를 이용한 골절 치료에서, 골절 부위에서의 절골편간 운동은 골절의 치유과정에 다양한 영향을 미친다고 알려져 있고, 이 미세 운동은 외고정장치-절골편 시스템의 강성과 밀접한 관련이 있다. 그렇기 때문에 최적의 골절 치유 과정을 부여하기 위하여 외고정장치 시스템의 구성 인자와 강성과의 연관성에 대한 이해가 필요하다. 본 연구에서는 장골 골절의 외고정술에 대한 유한요소 해석에서 외고정장치 시스템의 구성인자가 시스템 강성에 미치는 영향을 조사하였다. 이를 위하여, 시스템 정렬, 재료 비선형성, 조인트 유연성 및 가골형성 등을 해석 인자로 선정하였다. 개발된 유한요소 모델은 실험 결과와 유사한 시스템 강성을 나타내었고, 조인트 유연성 및 재료 비선형성의 고려는 시스템 강성 결과를 더욱 정확하게 반영하였다. 시스템 비정렬상태, 조인트 유연성 및 재료 비선형성은 시스템 강성의 감소를, 그리고 골절 부위의 가골형성은 시스템 강성의 증가를 나타내었다. 본 연구 결과는 외고정술시 시스템 강성을 증가시키기 위한 프레임 구성이나 기구 설계 등의 도구로 사용될 수 있을 것으로 기대된다. 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.

역동역학해석 기술을 이용한 보행 중 슬관절 접촉력 예측

김윤혁,박원만,프티탄픙 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.4

이형성 고관절의 선반형성슬 전 · 후에서의 접촉압력 분포의 변화

김윤혁 경희대학교 산학협력기술연구원 2005 산학협력기술연구논문집 Vol.11 No.3

In this study, the change of contact pressure between pre-operative and post-operative hip joint in the shelf operation was analyzed using finite element method. 2D-CT images from femur to pelvis were used to construct the finite element models, and the resultant force in the hip joint was calculated using the 3D expansion of the Ninomiya’s method. The dysplastic hip joint before the shelf operation surgery had lower center-edge angle, which is determined by the femoral head center and the lateral border of acetabulum, and higher contact pressure distribution than the hip joint after the surgery. The surgery recovered the center-edge angle to the normal anatomical range and increased the contact pressure area, thus decreasing the maximum contact pressure by 22 %. The present analysis method provides the biomechanical guideline of the optimal surgical planning to maximize the clinical outcomes in the surgery of hip dysplasia.

공학해석을 위한 의료영상 정보 기반 생체역학 모델링 및 시뮬레이션

김윤혁,Kim, Yun-Hyeok 한국과학기술정보연구원 2006 지식정보인프라 Vol.21 No.-

One-Pot Synthesis of Highly Monodisperse Poly(lactic-co-glycolic Acid) Particles with Controlled Porosity as Efficient Drug Delivery Vehicles

김윤혁,변준형,김병재,이기정,이재승,김태훈 대한화학회 2019 Bulletin of the Korean Chemical Society Vol.40 No.9

Poly(lactic-co-glycolic acid) (PLGA) particles are one of the most widely used biocompatible and biodegradable materials, and have been extensively investigated as drug delivery vehicles. While a number of different types of additives have been used during and after the synthesis of the PLGA particles for the enhancement of their functions, the shape control of the particles and observations of their shape-dependent properties have been rarely reported to date. To overcome the limitations of conventional PLGA particles, including the slow degradation of PLGA and the resultant slow drug release, we synthesized porous PLGA particles with much higher surface area than in previous works. Unlike in previous studies, the porous PLGA particles in this work exhibit distinctive advantages such as a simpler synthetic scheme, improved size monodispersity, and controllable pore size distribution (approximately 1 ?m in diameter). Polyethylenimine (PEI) was chosen as a pore-generating material, which simplified the synthesis process significantly. The performance of the porous PLGA particles was evaluated using doxorubicin (DOX) and the A549 cell line as a drug and target cells of a model system, respectively. Based on the observation of the cell viability, the DOX-loaded porous PLGA particles were determined to be five times more efficient than molecular DOX.

A Laboratory-level Surgical Robot System for Minimal Invasive Surgery (MIS) Total Knee Arthroplasty

김윤혁,Huynh Le Minh 한국정밀공학회 2011 International Journal of Precision Engineering and Vol.12 No.2

Recently, commercially available computer-aided surgical robot systems have been introduced to enable surgeons to improve the accuracy of cutting and alignment in total knee arthroplasty (TKA). The minimal invasive surgery (MIS) in the TKA has been increased since MIS can improve the surgical outcomes such as the recovery time and hospital stay by reducing the incision in surgery. However, current surgical robot systems do not provide the MIS TKA capability. In this study, we developed a laboratory-level surgical robot system to cut the bone from the lateral direction of the knee joint to provide MIS TKA. TKA experiments with saw bones of femur were compared between the conventional approach and the MIS approach. The incision length for the working space of the cutting tool and bone cutting time were decreased in lateral direction bone cutting. In addition, the cutting surface was smoother and the ranges of motion of all six joints were decreased in lateral direction bone cutting. Moreover, the cutting accuracy in terms of the lengths and angles of five cutting planes in femur were smaller in lateral approach than those in conventional approach. Therefore, consideration of bone cutting from the lateral direction in robotic TKA surgery should be necessary to improve the surgical outcomes in knee arthroplasty. The developed surgical robot system could be a platform of various orthopedic robotic surgeries.

유한요소법을 이용한 추적 하중 조건에서의 2 차원 요추 근육 작용 해석

김윤혁,김경수 경희대학교 산학협력기술연구원 2005 산학협력기술연구논문집 Vol.11 No.4

The lumbar spine can support a much larger compressive load if it applies along the follower load path that approximates the tangent to the curve of the lumbar spine compared with the vertical load path. In order to investigate the quantitative role of multisegmental muscles to the generation of follower loading patterns, a mathematical model of the human lumbar spine subjected to a follower load was developed in the frontal plane using the finite element method.

컴퓨터 내비게이션 인공슬관절 수술 후 연령에 다른 대퇴골 골절 위험성

김윤혁,박원만 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5

척추 질환 치료/재활을 위한 노령 척추 CAE 모델 및 의료기기 제품화 기술

김윤혁,박원만 대한기계학회 2015 기계저널 Vol.55 No.3

Recent advances in finite element modeling of the human cervical spine

김윤혁,Batbayar Khuyagbaatar,김경수 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.1

The human cervical spine is a complex structure that is the most frequently injured site among all spinal injuries. Therefore, understanding of the cervical spine injury and dysfunction, and also biomechanical response to external stimuli is important. Finite element (FE) modeling can help researchers to access the internal stresses and strains in the bones, ligaments and soft tissues more realistically, and it has been widely adopted for spine biomechanics research. Although in recent years numerous techniques have been developed, there are no recent literature reviews on FE models of the cervical spine. Our objective was to present recent advances in FE modeling of the human cervical spine in terms of component modeling, material properties, and validation procedures. Model applications and further development are also discussed. The integration of new technologies will allow us to generate more accurate and comprehensive model of the cervical spine, which can increase efficiency and model applicability. Finally, the FE modeling can help to facilitate diagnosis, treatment, and prevention technologies for cervical spine injuries.