• Journal of Korean Neurosurgical Society
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• 제29권8호
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• pp.1113-1120
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• 2000

Objectives : Despite advance in the surgical treatment of the intracranial aneurysm, we have to be surgical complication. The aim of this report is to evaluate the complication and its management in intracranial aneurysm operation. Methods : We reviewed our exprience with interesting cases of surgical complication of intracranial aneurysm : 1) rebleeding, 2) intra-operative premature rupture, 3) missed aneurysm in angiography, 4) vasospasm. Results : The risk of rebleeding was not related to the patients' initial comdition, but all other intracranial complications occurred significantly more often in patients graded poor compared with patients in good clinical condition. Rebleeding before early surgery remains as major cause of unfavorable outcome. The causes of intraoperative premature ruptures were as follows : 1) dural opening and arachnoid opening(8.3%), 2) hematoma removal(12.5%), 3) brain retraction(16.7%) 4) aneurysm dissection(62.5%). The double suction technique and primary hemostasis using a small piece of cotton or temporary clip resulted in good outcome even in cases with premature rupture. The incidence of missed aneurysm in angiography occurred in 10%. The causes were as thrombosed aneurysm, vasospasm on feeder artery. The most common missed aneurysm is also the most common aneurysm(anterior communicating artery aneurysm). The repeated angiography were documented in missed aneurysm. Balloon angioplasty is superior topapaverine for treatment of proximal vessel vasospasm by viture of a more sustained effect on the vessel. Papaverine can be useful as an adjunct to ballon angioplasty and also for the treatment of distal vessels that are not accessible for ballon angioplasty. Conclusion : The minimization of the complications and active treatment can reduced the mortality and morbidity of ruptured aneurysm patients.

• Journal of Mechanical Science and Technology
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• 제17권9호
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• pp.1380-1387
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• 2003

When a cold HPSI (High pressure Safety Injection) fluid associated with an overcooling transient, such as SGTR (Steam Generator Tube Rupture), MSLB (Main Steam Line Break) etc., enters the cold legs of a stagnated primary coolant loop, thermal stratification phenomena will arise due to incomplete mixing. If the stratified flow enters the downcomer of the reactor pressure vessel, severe thermal stresses are created in a radiation embrittled vessel wall by local overcooling. As general thermal-hydraulic system analysis codes cannot properly predict the thermal stratification phenomena, RG 1.154 requires that a detailed thermal-mixing analysis of PTS (pressurized Thermal Shock) evaluation be performed. Also. previous PTS studies have assumed that the thermal stratification phenomena generated in the stagnated loop side of a partially stagnated primary coolant loop are neutralized in the vessel downcomer by the strong flow from the unstagnated loop. On the basis of these reasons, this paper focuses on the development of a 3-dimensional thermal-mixing analysis model using PHOENICS code which can be applied to both partial and total loop stagnated cases. In addition, this paper verifies the fact that, for partial loop stagnated cases, the cold plume generated in the vessel downcomer due to the thermal stratification phenomena of the stagnated loop is almost neutralized by the strong flow of the unstagnated loop but is not fully eliminated.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2961-2966
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• 2007

When the pressure at the weak spot established at a certain part of a high pressure vessel or piping system exceeds a design pressure, this weak spot is burst, and the pressurized gas emitted through the weak spot will cause a compression wave system. In this connection, in the present study, an experimental study by using a conventional shock tube facility is performed to estimate the effects of the material of diaphragm, curvature radius and thickness of materials on the valve opening time in diaphragm. Pressure sensor having 500kHz in natural frequency is installed at 35mm downstream of the rupture diaphragm to measure the static pressure history of propagating and being accumulated compression wave. 4 kinds of materials are used as diaphragm that is aluminium, copper, stainless steel and zinc. The diaphragm radii of curvature R are ${\infty}$, 120mm and 60, respectively. And the depth for $90^{\circ}$ groove is 0.04mm. It is found that the smaller the tensile strength and elongation of the rupture diaphragm is, the smaller the radius of curvature of the rupture diaphragm is, and for the same conditions the thinner the thickness of the rupture diaphragm is, the shorter the valve opening time becomes. Also, the tensile strength, elongation and the radius of curvature of the rupture diaphragm for the same conditions are smaller, the maximum pressure rise caused by the coalescences of the compression wave is smaller. Finally the pressure ratio is higher, the valve opening time is shortened and gradient of pressure increment is more steepen.

• Journal of Korean Neurosurgical Society
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• 제65권4호
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• pp.531-538
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• 2022

Objective : Anterior communicating artery (Acom) aneurysm is one of the most common intracranial aneurysms, constituting approximately 30-35% of all aneurysm formation in the brain. Anatomically, the H-complex (the anatomic morphology of both A1 to A2 segments) is thought to affects the nature of the Acom aneurysm due to its close relationship with the hemodynamics of the vessel. Therefore, we investigated the relative risk factors of aneurysmal rupture, especially focusing on H-complex morphology of the Acom. Methods : From January 2016 to December 2020, a total of 209 patients who underwent surgery, including clipping and coiling for Acom aneurysm in our institution were reviewed. There were 102 cases of ruptured aneurysm and 107 cases of unruptured aneurysm. The baseline morphology of aneurysms was investigated and the relationship between the H-complex and the clinical characteristics of patients with Acom aneurysms was assessed. Results : Of the 209 patients, 109 patients (52.1%) had symmetrical A1, 79 patients (37.8%) had unilateral hypoplastic A1, and 21 patients (10.0%) had aplastic A1. The hypoplastic A1 group and the aplastic A1 group were grouped together as unilateral dominancy of A1, and were compared with the symmetrical A1 group. There was no significant difference in demographic characteristics and radiological findings of Acom aneurysms between two groups. However, when dichotomizing the patients into ruptured cases and unruptured cases, unilateral dominance of the A1 segment was associated with aneurysmal rupture with statistical significance (p=0.011). Conclusion : These results suggest that the unilateral dominance of the A1 segment does not have a significant effect on the morphology of Acom aneurysms, but contributes to aneurysmal rupture. Thus, we can better understand the effects of hemodynamics on Acom aneurysm.

• 한국항공우주학회지
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• 제38권6호
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• pp.605-611
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• 2010

정지궤도위성인 통신해양기상위성은 2010년 발사 예정인데, 관련된 일련의 성능 시험중에는 수백 기압의 헬륨 가스로 채워진 추진계 탱크의 고압 내구 시험도 포함되어 있다. 이 논문에서는 시험 시스템에 최악의 사고가 일어날 경우를 대비하여 그 위험도를 계산하여 보았다. 두 가지 시나리오가 있는데, 첫째는 310 기압의 헬륨 탱크가 현재의 시험챔버에서 일시에 파열하는 경우, 둘째는 116 기압의 감압된 헬륨 탱크가 방탄유리로 보호되고 있는 방에서 파열하는 경우를 가정해 보았다. 폭발파 전파 이론과 전산 수치 모사를 통하여, 제한된 공간에서 반사되는 파동의 역학을 매우 복잡한 비정상 유동 물리에 대하여 분석하였다.

• Journal of Chest Surgery
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• 제10권1호
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• pp.82-89
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• 1977

A rupture of a dissecting aneurysm of the aorta is life threatening disease and calls for emergency surgical treatment. The author recently experienced one case of ruptured dissecting aneurysm of the descending thoracic aorta complicated with left hemothorax who was recovered after emergency operation of Aug. 11, 1976. The patient was a 43 years old farmer with known hypertension [260/120] for 20 years but without any venereal disease and had experienced sudden throbbing chest pain. Chest film and aortogram revealed this case ruptured aneurysm of descending thoracic aorta complicated with left hemothorax. In this case, large dissecting aneurysm extend from proximal part of left subclavian artery below diaphragm and involved with 3.0 and 4.0cm sized elliptical rupture in proximal part of descending thoracic aorta. And so, neither fenestration procedure nor replacement of dacron artificial vessel was suitable for this case. Finally, only the rupture site of aneurysm was treated by covering with fibrous pleura and teflon patch. The post-operative management of this case was planned to control hypertension with antihypertensive drugs. The follow-up was possible up to date about 2months. The patient has been doing well with ordinary activities except mild chest discomfort.

• Journal of Korean Neurosurgical Society
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• 제29권12호
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• pp.1584-1591
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• 2000

Objective : Until now, it has been little known about the biological mechanisms associated with the genesis, growth, and rupture of intracranial aneurysm. This study was performed to investigate and understand a part of these mechanisms. Materials and Methods : Immunohistochemical stains for angiogenesis growth factors(basic fibroblast growth factor (bFGF) and vascular endothelial growth factor(VEGF)) and selected vascular wall matrix proteins(alpha smooth muscle actin(${\alpha}SMA$) and collagen Type IV) were performed in fixed sections from a normal circle of Willis artery which was taken from the autopsy specimen as a control vessel and 17 aneurysmal wall specimens which was taken during surgical clipping of aneurysms. The staining intensity and distribution of immunoreactivity to angiogenesis growth factors and selected wall matrix proteins in control vessel and aneurysmal wall were examined and compared with each other. The difference of staining intensity according to the size of aneurysm was also investigated. Results : There was no immunoreactivity to bFGF and VEGF in the control vessel. bFGF immunoreactivity was exhibited in 15 of 17 aneurysm specimens around smooth muscle cells within the media of aneurysm. VEGF immunoreactivity was also exhibited in all aneurysm specimens in patches or diffusely affecting all layers of the aneurysmal wall. The degrees of intensity of bFGF and VEGF immunoexpression were proportionate roughly to the size of aneurysm. Strong immunoexpression of both factors were noticed in large aneurysm. A regularly arranged and defined band of immunoreactivity of ${\alpha}SMA$ was noticed in the media of the control vessel, whereas diffuse, faint, irregularly arranged ${\alpha}SMA$ was noticed in the aneurysmal wall. A regularly defined band of collagen Type IV immunoreactivity was also noticed in the subendothelium of the control vessel, whereas diffuse disorganized immunoreactivity of collagen Type IV was noticed in the entire wall of the aneurysm. Conclusion : These results indicate substantial evidences of abnormal expression of angiogenesis factors and changes of selected vascular wall matrix proteins in the wall of intracranial aneurysm. The unbalanced changes of angiogenesis factors and vascular wall matrix proteins in the wall of aneurysm may be one of the biological mechanisms for the growth and rupture of aneurysm.

• Journal of Yeungnam Medical Science
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• 제35권1호
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• pp.121-126
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• 2018

Coronary spasm generally occurs in patients with minimal atherosclerotic plaque lesion, and it has a rather favorable prognosis. However, in some cases, coronary spasm may induce myocardial infarction and even sudden cardiac death (SCD). Here, we report a case in which multi-vessel intractable coronary vasospasm suddenly occurred in a diffuse atherosclerotic lesion after percutaneous coronary intervention (PCI) in a patient with aborted SCD. We identified the characteristics of the spasm portion in intravascular ultrasound (IVUS) images and conducted percutaneous cardiopulmonary bypass support-PCI with stenting as treatment. Intima and media thickening and a large attenuated plaque burden with rupture were identified in IVUS images at the obstructive spasm portion.

• Journal of Trauma and Injury
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• 제18권2호
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• pp.172-174
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• 2005

Trauma of the vascular structure is not poplular event. In obstructive atherosclerotic vascular disease, we sometimes have needed bypass surgery. The long length subcutaneous prosthetic vascular graft are vulnerable to injury. But prosthetic vessel rupture after trauma has been rare report. A 68-year-old man was referred to Department of Emergency of the Gyeongsang National University Hospital. After he had had a blunt trauma, he found a newly appearing pulsating mass of 10 cm diameter on his right chest wall. The lesion had a turbulent blood flow in the cavity of the mass by ultrasonographic finding. The lesion was a rupture of superficial prosthetic vascular graft under the skin.

• 한국정밀공학회지
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• 제22권9호
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• pp.179-187
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• 2005

The characteristics of blood flow and the interaction between the blood vessel and blood flow play important roles in plaque cap rupture and the growth of atherosclerosis which may lead directly to a heart attack or a stroke. In this study, carotid arteries with different stenoses have been numerically simulated to investigate the wall shear stress(WSS) and the elastic motion of the vessel. Blood flow has been treated as physiological, laminar and incompressible flow. To model the shear thining behavior of the blood, the Carreau-Yasuda model has been employed but the viscoelasticity of blood has not been considered. The results show that the WSS of $severe(75\%)$ stenosis is much higher than those of $25\%\;and\;50\%$ stenosis in the region of stenosis. With the increase in the stenosis thickness, the expansion ratio of the center of the stenosis decreases while the expansion ratio of the upstream region of the stenosis increases.