• 폴리머
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• 제35권3호
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• pp.260-264
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• 2011

생분해성 고분자 스텐트는 상대적으로 향상된 생체적합성 및 낮은 부작용으로 기존의 비분해성 금속 스텐트를 대체하기 위해 이슈가 되고 있다. 기본적으로 오든 스텐트들은 확장된 혈관의 직경을 유지하기 위해 요구되는 기계적 강도, 특히 압축력 또는 팽창력을 가져야만 한다. 따라서 본 연구는 나선형 구조테를 제안하였으며, 측면 압축력과 구조적 인자들과의 관련성에 집중하였다. 실린더의 구조체와 달리, 나선형 구조체의 팽창력은 두께와 길이에 1차승으로 비례하고, 직경은 1.6지승의 반비례 관계를 가지고 있었다. 하지만 간극 사이의 거리는 하중과 관련성을 보이지 않았다. 본 연구에서 얻어진 이러한 함수는 임상 적용 스텐트를 설계하고 제조하는데 기초적인 정보를 제공할 수 있다.

• Journal of Chest Surgery
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• 제43권6호
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• pp.739-742
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• 2010

투석중인 40세의 만성 신부전 환자가 우측 쇄골하정맥 협착증으로 지역병원에서 2개의 스텐트를 삽입하였다. 경과 관찰 중 한 개의 스텐트가 우심실로 이동하면서 삼첨판막 폐쇄부전이 발생하였다. 경피적으로 스텐트 제거를 시도하였으나 실패하여 개흉 성장수술로 제거하면서 삼첨판막 성형술을 시행하여 좋은 결과를 보였기에 보고하고자 한다.

• Journal of Korean Neurosurgical Society
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• 제51권3호
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• pp.155-159
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• 2012

The treatment of bilateral vertebral artery dissecting aneurysms (VADAs) presenting with subarachnoid hemorrhage (SAH) is still challenging. The authors report a rare case of bilateral VADA treated with coil trapping of ruptured VADA and covered stents implantation after multiple unsuccessful stent assisted coiling of the contralateral unruptured VADA. A 44-year-old woman was admitted to our hospital because of severe headache and sudden stuporous consciousness. Brain CT showed thick SAH and intraventricular hemorrhage. Cerebral angiography demonstrated bilateral VADA. Based on the SAH pattern and aneurysm configurations, the right VADA was considered ruptured. This was trapped with endovascular coils without difficulty. One month later, the contralateral unruptured VADA was protected using a stent-within-a-stent technique, but marked enlargement of the left VADA was detected by 8-months follow-up angiography. Subsequently two times coil packing for pseudosacs resulted in near complete occlusion of left VADA. However, it continued to grow. Covered stents graft below the posterior inferior cerebellar artery (PICA) origin and a coronary stent implantation across the origin of the PICA resulted in near complete obliteration of the VADA. Covered stent graft can be used as a last therapeutic option for the management of VADA, which requires absolute preservation of VA flow.

• Clinical and Experimental Pediatrics
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• 제50권9호
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• pp.919-924
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• 2007

폐정맥 협착은 선천적 또는 총 폐정맥 환류 이상 완전교정술 후에 이차적으로 발생한다. 선천적, 후천적 폐정맥 협착은 많은 연구에도 불구하고 예후가 대단히 불량한 것으로 알려져 있다. 저자들은 총 폐정맥 환류 이상 완전교정술 후에 이차적으로 발생한 폐정맥 협착 환아 2명에게 풍선 혈관 성형술 후 협착부가 다시 좁아져서 스텐트 삽입술을 시행하여 증상이 호전되다가 다시 진행성 협착이 발생하여 사망한 2례를 보고하는 바이다.

• Smart Structures and Systems
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• 제8권1호
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• pp.1-15
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• 2011

Cerebral aneurysm is common lesion among adult population. Current methods for treating the disease have several limitations. Inspired by fern leaves, we have developed a new stent, called leaf stent, which can provide a tailored coverage at the neck of an aneurysm and thus prevent the blood from entering the aneurysm. It alone can be used to treat the cerebral aneurysm and therefore overcomes problems existing in current treating methods. The paper focuses on the numerical simulation of the leaf stents. The mechanical behaviour of the stent in various designs has been investigated using the finite element method. It has been found that certain designs provide adequate radial force and have excellent longitudinal flexibility. The performance of certain leaf stents is comparable and even superior to those of the commercially available cerebral stents such as the Neuroform stent and the Enterprise stent, commonly used for stent assisted coiling, while at the same time, providing sufficient coverage to isolate the aneurysm without using coils.

• 대한기계학회논문집A
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• 제28권7호
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• pp.915-922
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• 2004

A stent is small tube-like structure expanded into stenotic arteries to restore blood flow. The stent expansion behaviors define the effectiveness of the surgical operation. In this paper, finite-element method was employed to analyze expansion behaviors and fatigue life of a typical diamond-shaped balloon-expandable stent. Beyond safety considerations, this type of analysis provides mechanical properties that are often difficult to obtain by experiments. Mechanical properties of the stent expansion pressure, radial recoil, longitudinal recoil and foreshortening were simulated using commercial FEM code, ANSYS and fatigue life were estimated using NISAII ENDURE. The FEM results showed that the pressures necessary to expand the stent up to a diameter of 3mm, 4mm and 5mm were 0.75MPa, 0.82MPa and 0.97MPa. The fatigue lifes according to expansion diameter were 114${\times}$10$^{7}$cycles, 714${\times}$$^{6}$cycles and 163${\times}$10$^{6}$cycles. As a result, a finite element model used in this study can simulate expansion behaviors of stents and should be useful to design new stents or analyze actual stents.

• 대한기계학회논문집A
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• 제29권1호
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• pp.156-162
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• 2005

Stouts are frequently used throughout the human body, but the most critical areas are in coronary arteries. They open pathways in vessels and supply blood directly to the heart muscle. To simulate behavior of expansion for the coronary stent by balloon, the commercial finite element code LS-DYNA and ANSYS were used in the analysis. The explicit method is used to analyze the expansion of the stent and the implicit method is performed to simulate the springback that developed in a stent after the balloon pressure has been removed. Finally the experimental results for the expansion of the PS153 stents were compared with the FEM results. The springback was measured with the stents subjected to no external pressure to which stents are subjected in vivo. The simulated results were in good agreement with experimental results. Standard mechanical characteristics such as stress, plastic strains, and springback can be derived from the numerical results. These data can be used to determine maximum expansion diameter without fracture and expansion pressure considering elastic recoil.

• Journal of Veterinary Science
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• 제23권4호
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• pp.58.1-58.10
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• 2022

Background: Laryngeal paralysis is a common idiopathic degenerative neurological disease in older medium-to-large breed dogs, with surgical correction of the obstruction being the treatment of choice. Objectives: This study evaluated the use of laryngeal silicone stents to treat canine laryngeal paralysis in dogs where classic surgical treatment was not accepted by the owners. Methods: Dogs diagnosed with laryngeal paralysis, for which the owners refused arytenoid lateralization surgery as a first-line treatment, were treated with laryngeal silicone stents. Results: Six dogs with bilateral laryngeal paralysis were included in the study. All dogs showed improvement in clinical signs immediately after the procedure. No clinical signs or radiographic changes were noted in four out of six dogs in the follow-up visit performed 1 wk later. One dog was suspected of aspirating water while drinking, but the signs disappeared after repositioning the stent. Another dog had a relapse of stridor due to caudal migration of the stent. This dog underwent arytenoid lateralization surgery because larger stents are not commercially available. At the time of writing, between seven and 13 mon after stent placement, no significant incidents have occurred in four dogs, and all owners report a satisfactory quality of life. Conclusions: Laryngeal silicone stenting is an interesting alternative for treating dogs with acquired laryngeal paralysis when the owners refuse classic arytenoid lateralization surgery. Furthermore, stent placement can be a temporary solution to stabilize these dogs until a permanent surgical treatment can be performed.

• 대한의용생체공학회:의공학회지
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• 제24권1호
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• pp.37-44
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• 2003

본 실험연구에서는 정상유동상태에서 새롭게 설계된 자가팽창성 그래프트 스텐트의 수력학적 성능을 평가하고자 하였다. 코팅 재질이 다른 두 개의 그래프트 스텐트와 한 개의 타이티놀 금속스텐트가 실험에 사용되었으며, 유량이 가자 5, 10, 15 1/min에서 스텐트 전후에서의 압력변화 및 속도분포를 측정하였다. 스텐트 삽입에 의한 압력손실은 유량이 증가함에 지수적으로 증가하였다. 특히 15 1/min의 유량에서 다공성 PTFE 그래프트 스텐트와 TiNi 금속스텐트의 압력손실은 거의 동일하나 PU 그래프트 스텐트는 약 6배 이상의 현저한 증가를 보이고 있다. 스텐트 후류에서의 속도분포는 다공성 PTFE 그래프트 스텐트와 TiNi 금속스텐트는 유량에 관계없이 유사한 형태를 보여주고 있다. 그러나, PU 그래프트 스텐트에서는 특히 유량이 10 1/min 이상에서 속도분포가 비대칭적이고 관 중심에서의 상대적인 낮은 유속을 보여주고 있으며, 결과적으로 벽면전단응력 및 수직응력의 증가론 초래하고 있다. 이와같이 PU 그래프트 스텐트의 상대적으로 낮은 수력학적 성능은 스텐트가 보다 작은 관에 삽입되었을때 코팅재질의 낮은 유연성으로 인하여 스텐트의 표면에 주름이 발생하여 유동단면이 비대칭적으로 되고 벽면의 조도가 증가하며, 관벽과 스텐트와 틈새가 존재하여 제트류가 형성되기 때문으로 해석된다.

• 대한임상약리학회:학술대회논문집
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• 대한임상약리학회 2006년도 제15차 추계학술대회
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• pp.92-92
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• 2006