• Journal of Korean Neurosurgical Society
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• 제40권1호
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• pp.16-21
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• 2006

Objective : Young neurosurgeons need to focus on the mortality and morbidity of aneurysmal neck clipping to develop a personal experience with an initial series. Methods : Total 88 aneurysms from 75 patients who underwent neck clipping by the same operator from 2001 to 2004 were reviewed. Patients were divided into three groups : first year [Group I], second year [Group II], and third year [Group III] in each group. Location of aneurysm, age, Fisher grade, Hunter-Hess grade [H-H grade], postoperative Glasgow outcome scale [GOS], and complications related to surgical procedures were evaluated with Chi-square and logistic regression analyses. Results : Fourteen patients had complications related to surgery [18.7%]. The major causes of mortality and morbidity related to surgery were cerebral infarction, hemorrhage and brain swelling due to intraoperative rupture, brain retraction and vasospasm. Among the 4 cases of mortality were 2 patients in Group I, 1 patient in Group II and 1 patient in Group III, and location of aneurysms were 2 internal carotid artery[ICA] and 2 posterior communicating artery[PCoA] aneurysms. There were 4 morbidity and new neurological deficits in Group I, 4 in Group II and 2 in Group III. Although mortality and morbidity during the learning curve had a statistical significance in H-H grade, age [>60 years old], and aneurysm location [especially ICA aneurysm] as variables, mortality mainly occurred in ICA and PCoA aneurysms. Conclusion : Experienced supervision or endovascular approach should be considered for the treatment of ICA and PCoA aneurysms during the learning curve.

• Biomaterials and Biomechanics in Bioengineering
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• 제2권2호
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• pp.111-125
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• 2015

For engineers, generating a mesh in porous media (PMs) sometimes represents a smaller computational load than generating realistic stent geometries with computer fluid dynamics (CFD). For this reason, PMs have recently become attractive to mimic flow-diverter stents (FDs), which are used to treat intracranial aneurysms. PMs function by introducing a hydraulic resistance using Darcy's law; therefore, the pressure drop may be computed by test sections parallel and perpendicular to the main flow direction. However, in previous studies, the pressure drop parallel to the flow may have depended on the width of the gap between the stent and the wall of the test section. Furthermore, the influence of parameters such as the test section geometry and the distance over which the pressure drops was not clear. Given these problems, computing the pressure drop parallel to the flow becomes extremely difficult. The aim of the present study is to resolve this lack of information for stent modeling using PM and to compute the pressure drop using several methods to estimate the influence of the relevant parameters. To determine the pressure drop as a function of distance, an FD was placed parallel and perpendicular to the flow in test sections with rectangular geometries. The inclined angle method was employed to extrapolate the flow patterns in the parallel direction. A similar approach was applied with a cylindrical geometry to estimate loss due to pipe friction. Additionally, the pressure drops were computed by using CFD. To determine if the balance of pressure drops (parallel vs perpendicular) affects flow patterns, we calculated the flow patterns for an ideal aneurysm using PMs with various ratios of parallel pressure drop to perpendicular pressure drop. The results show that pressure drop in the parallel direction depends on test section. The PM thickness and the ratio of parallel permeability to perpendicular permeability affect the flow pattern in an ideal aneurysm. Based on the permeability ratio and the flow patterns, the pressure drop in the parallel direction can be determined.

• Journal of Korean Neurosurgical Society
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• 제64권1호
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• pp.39-50
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• 2021

Objective : The treatment of large aneurysms of the posterior circulation is complicated and remains challenging. We here analyzed our institutional clinical outcomes of large unruptured aneurysms of the posterior circulation. Methods : This study included 56 patients who presented with a large (>10 mm) unruptured aneurysm of the posterior circulation between 2002 and 2018. Results : There were 18 (32.1%) male and 38 (67.9%) female patients, with a mean age of 53.4 years. The most common location was the vertebral artery, followed by the basilar tip and posterior cerebral artery. The median follow-up duration was 29 months. Eighteen patients (32.1%) were treated by transcranial surgery and 38 (67.9%) were treated by endovascular treatment (EVT). Post-treatment complications occurred in 16 patients (28.6%), with there being no significant difference between the transcranial surgery and EVT groups. Complete obliteration was achieved in 30 patients (53.6%), with there being no statistically significant difference between the transcranial surgery and EVT groups. Recurrence occurred in 17 patients (30.4%), and the rate of recurrence was higher in the EVT group than in the transcranial surgery group (39.5% vs. 11.1%, p=0.03). Forty-four (84%) of 56 patients showed a favorable functional outcome. In saccular aneurysm, EVT was negative predictor of worsening of functional status. Conclusion : Treatment of these aneurysms harbors an inherent high risk of morbidity. No superiority was found between transcranial surgery and EVT in terms of complications and complete obliteration, but transcranial surgery showed a higher treatment durability than EVT.

• 한국산학기술학회논문지
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• 제18권8호
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• pp.240-247
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• 2017

자기공명혈관영상(magnetic resonance angiography: MRA)을 이용한 뇌혈관검사가 증가하면서 비파열 동맥류의 발견이 많아졌다. 비파열 동맥류(unruptured intracranial aneurysm: UIA)의 병태생리 이해를 위해 비파열 동맥류의 분포와 관련요인을 아는 것이 도움이 될 것으로 생각한다. 환자군은 건강검진 시 MRA를 시행받은 사람을 대상으로 하였다. 비파열 동맥류의 발생과 위험요인(나이, 성별, 고혈압, 당뇨, 흡연, 음주력, 관상동맥질환)을 크기(3 mm이상 대 3 mm미만)와 다발성 동맥류(단일 대 다발성 동맥류)에 따라 비교하였다. 그리고 위치에 따른 비파열 동맥류 발생 빈도를 비교하였다. 2007년 1월부터 2016년 12월까지 건강검진 센터를 방문하여 건강검진을 받은 사람을 대상으로 하였다. 건강검진을 받은 187166명의 사람 중 18954명이 MRA를 찍었으며, 이 중 367명(1.93%)이 비파열 동맥류를 보였다. 3 mm이상과 3 mm미만의 동맥류를 비교하였을 때 3 mm이상의 동맥류 환자군에서 평균 나이가 유의하게 높았다(3 mm이상 $57.16{\pm}8.47$ 대 3 mm미만 $55.12{\pm}8.19$; p=0.07). 고밀도 지질단백질(high-density lipoprotein)은 3 mm이상의 동맥류 환자군에서 유의하게 높았다(3 mm 이상 $55.95{\pm}16.03$ 대 3 mm미만 $50.85{\pm}13.65$; p=0.007). 고혈압은 다발성 동맥류 환자군에서 의미있게 높은 경향을 보였다(단일 동맥류 399명 중 153명(38.3%) 대 다발성 동맥류 35명 중 19명 (54.3%); p=0.065). 3mm미만의 동맥류는 내경동맥 말단부(34.3%)와 중대뇌동맥 분기부(16.4%)에서 호발하였다(p=0.003). 3 mm이상의 동맥류는 내경동맥 말단부(43.3%)와 중대뇌동맥 분기부(13.4%) 및 앞교통동맥(13.4%)에서 호발하였다(p=0.003). 동맥류는 크기 차이와 단일 혹은 다발성에 따라 서로 다른 위험요인과의 상관성을 보였으나, 두가지 위험요인 모두 혈관의 퇴행성 변화와 혈류역학적 장애가 동맥류 발생의 원인이 될 수 있다는 것을 보여준다.

• Journal of Korean Neurosurgical Society
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• 제29권7호
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• pp.923-928
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• 2000

Objective : The reliability of transcranial doppler sonography(TCD) for predicting delayed ischemic neurologic deficit( DIND) was investigated in patients with aneurysmal subarachnoid hemorrhage(SAH). Methods : The velocity of blood flow through the middle cerebral artery was measured by TCD in 70 patients treated surgically within 72 hours due to ruptured cerebral aneurysm. A correlation between measured maximal mean blood flow velocities and clinical factors including age, hypertension, Hunt-Hess grade, Fisher grade, DIND, and outcome was made. Results : An age-dependent reduction of the measured maximal mean velocities was found(r＝-0.4043, p<0.001). Flow velocities in hypertensive patients were significantly lower than in the normotensive individuals(two-tailed T test, p<0.05). There was no significant difference between the flow velocities and evaluated other clinical factors. When the flow velocities of 14 patients who developed DIND were compared with those of patients without deficits, no significant difference was seen. A significant increase in flow velocities in the days before the onset of DIND was found only in 4 of 14 cases. High flow velocities did not necessarily mean impending neurological deficits : 6 of 70 patients tolerated flow velocities over 160cm/s. Conclusion : We suggest that TCD readings have limited utility for predicting DIND following SAH, especially in older or hypertensive patients. More direct measurements of blood flow are necessary to adequately predict which patients are at high risk of DIND.

• 대한의용생체공학회:의공학회지
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• 제21권6호
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• pp.567-573
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• 2000

뇌동맥류는 뇌혈관의 일부가 풍선처럼 부풀어나는 혈관계 질환이며 뇌동맥류의 파열은 사망이나 심각한 후유 장애를 야기한다. 뇌동맥류의 다양한 발생 원인 중 혈관 내부의 혈류의 유동이 중요한 인자로 의심된다. 뇌동맥류의 형성에 미치는 혈류역학적 인자를 규명하기 위해 내경동맥에서 발생한 환자의 내경 동맥류 CT 사진을 이용하여 내경동맥류 모델을 제작하고, 모델 내부의 혈류유동장을 입자영상속도계를 이용하여 측정하였다. 동맥류가 발생한 내경동맥류 모델에서는 동맥류 원위부 목(distal neck)쪽과 반대쪽 내경동맥 벽에서 전단응력이 높게 나타났다. 동맥류 발생에 미치는 혈류역학적 인자를 규명하기 위해 동맥류를 제거한 내경모델을 제작하여 맥동유동에서 내부 유동장을 측정하였다. 심실수축기 동안 휘어진 내경동맥의 바깥쪽 벽에서 혈류의 혈관벽 부딪힘이 관찰되었으며 심실이완기 초반에도 이는 계속 유지되었다. 내경 동맥 내부의 부차적 유동특성을 연구하기 위해 동맥류 발생 위치에서 혈관 축과 수직인 평면의 유동장이 측정되었다. 혈관 단면에서는 휘어진 혈관의 바깥쪽에서 안쪽으로 시계방향의 와류가 형성되었으며, 이로 인해 혈관벽 바깥쪽과 시계방향으로 90도 정도 지역에서 전단응력이 높게 나타났다. 혈류 유동 특성과 동맥류 발생위치를 비교해 보면, 혈류의 혈관벽 부딪힘이 관찰되는 위치와 부차적 유동에 의해 전단응력이 크게 나타난 지역은 동맥류의 발생위치와 일치하였다. 따라서 혈류의 혈관벽 부딪힘과 부차적 유동에 의한 전단력이 동맥류 발생의 혈류역학적 요인으로 의심된다.

• Journal of Korean Neurosurgical Society
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• 제50권1호
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• pp.23-29
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• 2011

Objective : The aim of the study is to determine the efficacy of indocyanine green (ICG) videoangiography for confirmation of vascular anastomosis patency in both extracranial-intracranial and intracranial-intracranial bypasses. Methods : Intraoperative ICG videoangiography was used as a surgical adjunct for 56 bypasses in 47 patients to assay the patency of intracranial vascular anastomosis. These patients underwent a bypass for cerebral ischemia in 31 instances and as an adjunct to intracranial aneurysm surgery in 25. After completion of the bypass, ICG was administered to assess the patency of the graft. The findings on ICG videoangiography were then compared to intraoperative and/or postoperative imaging. Results : ICG provided an excellent visualization of all cerebral arteries and grafts at the time of surgery. Four grafts were determined to be suboptimal and were revised at the time of surgery. Findings on ICG videoangiography correlated with intraoperative and/or postoperative imaging. Conclusion : ICG videoangiography is rapid, effective, and reliable in determining the intraoperative patency of bypass grafts. It provides intraoperative information allowing revision to reduce the incidence of technical errors that may lead to early graft thrombosis.

• Parasites, Hosts and Diseases
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• 제51권6호
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• pp.755-757
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• 2013

Gnathostoma spinigerum can cause subarachnoid hemorrhage (SAH). The detection of specific antibodies in serum against G. spinigerum antigen is helpful for diagnosis of neurognathostomiasis. There is limited data on the frequency of G. spinigerum infection in non-traumatic SAH. A series of patients diagnosed as non-traumatic SAH at the Srinagarind Hospital, Khon Kaen University, Thailand between January 2011 and January 2013 were studied. CT or MR imaging of the brain was used for diagnosis of SAH. Patients were categorized as aneurysmal subarachnoid hemorrhage (A-SAH) or non-aneurysmal subarachnoid hemorrhage (NA-SAH) according to the results of cerebral angiograms. The presence of specific antibodies in serum against 21- or 24-kDa G. spinigerum antigen was determined using the immunoblot technique. The detection rate of antibodies was compared between the 2 groups. Of the 118 non-traumatic SAH patients for whom cerebral angiogram and immunoblot data were available, 80 (67.8%) patients had A-SAH, whereas 38 (32.2%) had NASAH. Overall, 23.7% were positive for specific antibodies against 21- and /or 24-kDa G. spinigerum antigen. No significant differences were found in the positive rate of specific antibodies against G. spinigerum in both groups (P-value=0.350).

• Journal of Korean Neurosurgical Society
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• 제58권4호
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• pp.328-333
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• 2015

Objective : The goal of this study was to assess the effect of high-dose simvastatin on cerebral vasospasm and its clinical outcome after aneurysmal subarachnoid hemorrhage (SAH) in Korean patients. Methods : This study was designed as a prospective observational cohort study. Its subjects were aneurysmal SAH patients who had undergone aneurysm clipping or coiling. They were assigned to 1 of 3 groups : the 20 mg, 40 mg, and 80 mg simvastatin groups. The primary end-point was the occurrence of symptomatic vasospasm. The clinical outcome was assessed with the modified Rankin Scale (mRS) score after 1 month and 3 months. The risk factors of the development of vasospasm were assessed by logistic regression analysis. Results : Ninety nine patients with aneurysmal SAH were treated and screened. They were sequentially assigned to the 20 mg (n=22), 40 mg (n=34), and 80 mg (n=31) simvastatin groups. Symptomatic vasospasm occurred in 36.4% of the 20 mg group, 8.8% of the 40 mg group, and 3.2% of the 80 mg group (p=0.003). The multiple logistic regression analysis showed that poor Hunt-Hess grades (OR=5.4 and 95% CI=1.09-26.62) and high-dose (80 mg) simvastatin (OR=0.09 and 95% CI=0.1-0.85) were independent factors of symptomatic vasospasm. The clinical outcomes did not show a significant difference among the three groups. Conclusion : This study demonstrated that 80 mg simvastatin treatment was effective in preventing cerebral vasospasm after aneurysmal SAH, but did not improve the clinical outcome in Korean patients.

• Journal of Korean Neurosurgical Society
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• 제61권4호
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• pp.458-466
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• 2018

Objective : To compare peri-operative any symptomatic stroke after carotid angioplasty and stenting (CAS), based on the application or absence of a cerebral protection device. Methods : A systematic literature review using PubMed, Embase, and the Cochrane Central was done across an online data base from January 1995 to October 2016. Procedures which were performed due to carotid dissection or aneurysm, procedures using covered stents or conducted in an emergency, were excluded. The primary endpoint was perioperative any symptomatic stroke within 30 days after the procedure. A fixed effect model was used in cases of heterogeneity less than 50%. Results : In the 25 articles included in this study, the number of stroke events was 326 (2.0%) in protected CAS and 142 (3.4%) in unprotected CAS. The use of cerebral protection device significantly decreased stroke after CAS (odds ratio [OR] 0.633, 95% confidence interval [CI] 0.479-0.837, p=0.001). In the publication bias analysis, Egger's regression test disclosed that the intercept was -0.317 (95% CI -1.015-0.382, p=0.358). Regarding symptomatic patients (four studies, 539 CAS procedures), the number of stroke was six (1.7%) in protected CAS and 11 (5.7%) in unprotected CAS. The protective effect against stroke events by cerebral protection device did not have a statistical significance (OR 0.455, 95% CI 0.151-1.366, p=0.160). Conclusion : The use of protection device significantly decreased stroke after CAS. However, its efficacy was not demonstrated in symptomatic patients. Routine use of protection device during CAS should be critically assessed before mandatory use.