• 산업공학
• /
• 제18권2호
• /
• pp.184-192
• /
• 2005

In recent research there has been intense interest in understanding how real option valuation (ROV) approaches might usefully complement conventional discounted cash flow (DCF) techniques. However, investment decision makers in a real world have been worried about adopting the ROV approaches mainly because of difficulty in technically understanding the theory of the ROV approaches as indicated by many researchers. With this difficulty in mind, we propose the opportunity cost model as another discrete-time model to value a deferral option. The main advantage of observing a real options value in terms of the opportunity cost concept is to provide a technique for practitioners to estimate a wide range of real options values without sticking to a financial option modelling. The fundamental ground for developing the opportunity cost model proposed in this paper lies in the work of dissecting the structure of the real options value into three categories: capital gain, expected opportunity loss, and expected opportunity gain. At the end of the paper, we will present a short illustrative example to demonstrate the applicability of the model.

• Journal of Chest Surgery
• /
• 제53권4호
• /
• pp.191-199
• /
• 2020

Surgeons recommend dissecting lymph nodes in the thorax, abdomen, and neck during surgery for esophageal cancer because of the possibility of metastasis to the lymph nodes in those areas through the lymphatic plexus of the esophageal submucosal layer. Extensive lymph node dissection is essential for accurate staging and is thought to improve survival. However, it can result in several complications, including chyle leakage, which refers to continuous lymphatic fluid leakage and can occur in the thorax, abdomen, and neck. Malnutrition, fluid imbalance, and immune compromise may result from chyle leakage, which can be potentially life-threatening if it persists. Therefore, various treatment methods, including conservative treatment, pharmacological treatment such as octreotide infusion, and interventions such as thoracic duct embolization and surgical thoracic duct ligation, have been applied. In this article, the risk factors, diagnosis, and treatment methods of chyle leakage after esophagectomy are reviewed.

• Molecules and Cells
• /
• 제45권10호
• /
• pp.673-684
• /
• 2022

The past two decades have witnessed an upsurge in the appreciation of adipose tissue (AT) as an immunometabolic hub harbouring heterogeneous cell populations that collectively fine-tune systemic metabolic homeostasis. Technological advancements, especially single-cell transcriptomics, have offered an unprecedented opportunity for dissecting the sophisticated cellular networks and compositional dynamics underpinning AT remodelling. The "re-discovery" of functional brown adipose tissue dissipating heat energy in human adults has aroused tremendous interest in exploiting the mechanisms underpinning the engagement of AT thermogenesis for combating human obesity. In this review, we aim to summarise and evaluate the use of single-cell transcriptomics that contribute to a better appreciation of the cellular plasticity and intercellular crosstalk in thermogenic AT.

• Journal of Chest Surgery
• /
• 제57권1호
• /
• pp.99-102
• /
• 2024

This article presents a straightforward hybrid arch technique for treating residual type B aortic dissecting aneurysms following type A repair (replacement of the ascending aorta) that employs a frozen elephant trunk (FET) straight vascular prosthesis. The debranch-first method involves only cutting and sewing the previous ascending graft, inserting the FET from zone 0, and debranching the arch vessels using a trifurcated graft. This technique is less invasive as it eliminates the need to manipulate the dissected distal arch aneurysm. We successfully applied this technique to 3 patients, with no instances of in-hospital death, stroke, or paraplegia. The debranch-first technique, combined with zone-0 FET insertion, simplifies the redo repair of residual type B aortic dissection.

• Journal of Cerebrovascular and Endovascular Neurosurgery
• /
• 제25권2호
• /
• pp.208-213
• /
• 2023

Flow-diverting stents (FDSs) have proven advantageous for the treatment of large, fusiform, and dissecting aneurysms that are otherwise difficult to treat. Retreatment strategies for recurrent large or giant aneurysms after FDSs are limited to overlapping implantation of an additional FDS or definitive occlusion of the parent vessel. We report a recurrent giant aneurysm that was initially treated with an FDS with coils and was successfully treated with an additional FDS. Visual symptoms due to the mass effect of the recurrent aneurysm were completely resolved, and follow-up digital subtraction angiography revealed complete obliteration of the aneurysm. Additional FDS implantation for the retreatment of incompletely occluded aneurysms after the initial FDS treatment may be feasible and safe. Further studies are required to validate these results.

• Journal of Chest Surgery
• /
• 제9권1호
• /
• pp.10-19
• /
• 1976

One hundred and seventy-four patients were treated in this Department since 1956. One hundred and fifteen patients of them were surgically treated. They were classified on the basis of the disease entity as follows; 48 case of thrombo-angiitis obliterance, 8 cases of Leriche syndrome, 12 cases of arterial embolism, 36 arterial aneurysm, 5 arterio-venous fistula, 15 arterial and venous injuries, 8 pulseless diseases, 2 coarctation of aortas, 15 varicose veins, 12 thrombophlebitis, 9 superior venacaval syndromes, 2 inferior vena caval obstructions and Raynaud's diseases. All the cases of the Burger's diseases were males, and half of them were in the fourth decades, 39 cases underwent undergone unilateral or bilateral sympathectomies. All the Leriche syndromes were males aged over fifty. Three cases out of six were suffering from diabetes mellitus. 2 cases underwent aorto-femoral bypass graft with Y-shaped dacrons. And two embolectomies were performed in 2 cases. Eight cases of arterial embolisms among 12 had mitral valvular diseases with auricular fibrillation The most common site of lodgement of emboli was femoral artery. Nine out of 14 underwent embolectomies with Fogarty catheters. There were 14 peripheral arterial aneurysms, 16 thoracic and/or abdominal aortic aneurysms, and 4 dissecting aneurysms. Most frequent cause of peripheral arterial aneurysms were external trauma. Thoracic and abdominal aortic aneurysms were non-traumatic. And four cases of the dissecting aneurysms had significant hypertension and aged over fifty. Among 5 cases of arteriovenous fistulas, 2 cases hand typical Branham's sign, and they were normalized after operation. Eight cases of pulseless disease were females and aged from three to twenty-five. Three out of them were treated surgically using dacron prosthetic grafts, but the results of the surgery were variable and not satisfactory. A case of coarctation of aorta was treated surgically with an excellent result. Fourteen out of 15 varicose veins underwent ligation of the saphenous vein system, exstirpation of the varicose veins, stripping or some combination of these methods. Two cases of superior vena caval syndromes were operated by bypass graft between the left innominate vein and the right auricle. Two cases of inferior vena caval obstructions were operated upon through right atrial route using extracorporial circulation. All the four cases of vena caval obstructions showed excellent results postoperatively. Two cases out of 12 thrombophlebitis underwent thrombectomies. One of two Raynaud's diseases was surgically treated with an excellent result.

• Journal of Korean Neurosurgical Society
• /
• 제44권4호
• /
• pp.228-233
• /
• 2008

Objective : The standard treatment strategy of intracranial aneurysms includes either endovascular coiling or microsurgical clipping. In certain situations such as in giant or dissecting aneurysms, bypass surgery followed by proximal occlusion or trapping of parent artery is required. Methods : The authors assessed the result of extracranial-intracranial (EC-IC) bypass surgery in the treatment of complex intracranial aneurysms in one institute between 2003 and 2007 retrospectively to propose its role as treatment modality. The outcomes of 15 patients with complex aneurysms treated during the last 5 years were reviewed. Six male and 9 female patients, aged 14 to 76 years, presented with symptoms related to hemorrhage in 6 cases, transient ischemic attack (TIA) in 2 un ruptured cases, and permanent infarction in one, and compressive symptoms in 3 cases. Aneurysms were mainly in the internal carotid artery (ICA) in 11 cases, middle cerebral artery (MCA) in 2, posterior cerebral artery (PCA) in one and posterior inferior cerebellar artery (PICA) in one case. Results : The types of aneurysms were 8 cases of large to giant size aneurysms, 5 cases of ICA blood blister-like aneurysms, one dissecting aneurysm, and one pseudoaneurysm related to trauma. High-flow bypass surgery was done in 6 cases with radial artery graft (RAG) in five and saphenous vein graft (SVG) in one. Low-flow bypass was done in nine cases using superficial temporal artery (STA) in eight and occipital artery (OA) in one case. Parent artery occlusion was performed with clipping in 9 patients, with coiling in 4, and with balloon plus coil in 1. Direct aneurysm clip was done in one case. The follow up period ranged from 2 to 48 months (mean 15.0 months). There was no mortality case. The long-term clinical outcome measured by Glasgow outcome scale (GOS) showed good or excellent outcome in 13/15. The overall surgery related morbidity was 20% (3/15) including 2 emergency bypass surgeries due to unexpected parent artery occlusion during direct clipping procedure. The short-term postoperative bypass graft patency rates were 100% but the long-term bypass patency rates were 86.7% (13/15). Nonetheless, there was no bypass surgery related morbidity due to occlusion of the graft. Conclusion : Revascularization technique is a pivotal armament in managing complex aneurysms and scrupulous prior planning is essential to successful outcomes.

• Journal of Trauma and Injury
• /
• 제18권1호
• /
• pp.70-79
• /
• 2005

Background: Abdominal compartment syndrome has multiple etiologies that are not only related to trauma but also any problem condition in the absence of abdominal injury. To determine whether prevention of the abdominal compartment syndrome after celiotomy for trauma victims justifies the use of temporary abdominal coverage with monofilament knitted polypropylene mesh (Malex mesh) in severely injured patients. Method: Medical records at the Ajou University Medical Center were reviewed for a 32-month period from May 1st, 2002 to December 31st, 2004. Twenty-nine consecutive patients requiring celiotomy who were survived until at the end of celiotomy received temporary abdominal coverage and staged abdominal repairs with Malex mesh. One of them was dissecting aortic aneurysm patient and the others were all trauma victims. Malex mesh prosthesis coverage was used in cases of abdominal compartment syndrome due to excessive fascial tension, severe bowel edema and retroperitoneal hemorrhage or edema followed by staged abdominal repairs. Result: Eighteen of twenty-nine patients were survived. Demographic characteristics, injury severity number of abdominal-pelvic bone injuries, mortality rate, complications, number of operations for permanent closure, required time for permanent closure showed no difference between man and women or child and adult. Except one dissecting aortic aneurysm patient, trauma cases showed $3.24{\pm}0.98$ injury sites. All cases that received temporary abdominal coverage and staged abdominal repairs did not show abdominal compartment syndrome. $10.08{\pm}5.85$ days and $2.27{\pm}0.82$ times of operation required making permanent abdominal closure after temporary abdominal coverage followed by staged abdominal repairs. Most of surviving patients have shown antibiotic-resistant organism and fungus infection. Patients who received permanent closure recovered from infectious problem completely. Conclusion: The use of Malex mesh for temporary abdominal coverage in severely injured patients undergoing celiotomy was effective treatment method.

• Journal of Chest Surgery
• /
• 제30권7호
• /
• pp.686-692
• /
• 1997

저자들은 1994년 2월부터 1995년 8월사이에 본 교실에서 흉부대동맥류로 외과적 치료를 받았던 15 례의 임상성적을 분석하여 수술수기 및 수술결과를 향상시키는 계기로 삼고저 한다. 남자가 9례, 여자 가 6례였으며 평균연령은 55.07$\pm$11.76세였다. 원인질환은 대동맥박리증이 9례, 죽상경화증이 4례, 외 상이 2례이었다. 9례에서 상행 대동맥 및 대동맥궁의 부분 및 완전 치환술을 시행하였으며 3례에서 하행 대동맥 및 흉복부 대동맥치 환술을 시행하였고, 1례에서는 전체 대동백치환술을 시행하였으며, 외 상성 대동맥류 2례에서는 단단문합하였는데 대동맥 박리증 환자에서는 Wheat씨 방법으로 봉합부위를 보강한 후 치환하였다. 9례에서는 정중흉골절개술을, 4례에서는 후외측 흉벽절개술을, 2례에서는 후외 측 흉부절개후 흉복부절개술을 시행하였다. 상행 대동맥 및 대동맥궁을 치환하였던 9례에서는 상대정맥을 통한 역행성 뇌관류를 평균 56.67$\pm$29.25분 동안 시행하였고 하행 대동맥 및 흉복부 대동맥을 치환하였던 3례에서도 고도의 저체온화를 시행하였는데 술후 항구적인 뇌나 척추 신경장애가 발생한 례는 없었다. 술후 외상성 복담즙에 의한 복막염, 다장기 기능부전, 악성고혈압에 의한 잔여 박리성 동 맥류파열로 3례(20%, 3/15)가 사망하였다. 술후 합병증으로는 출혈에 의한 재수술이 4례, 일시적인 의식장애 3례, 늑막삼출 등의 폐 합병증이 3례, 심낭압진 1례 있었다. 타의료기관에서 관찰중인 1례를 제외한 11례를 추적관찰중인데 사망하거나 만기 합병증을 보인 례는 없었다.

• Journal of Chest Surgery
• /
• 제36권6호
• /
• pp.427-430
• /
• 2003

합병증이 있거나 수술의 적응증이 되는 대동맥 질환 사망률과 이환율이 높지만 수술기법이 난해하고 적지 않은 수술부작용이 발생하는 바, 최근 들어 이들 질환을 혈관내 스텐트 삽입술로 치료하려는 시도가 늘어가고 있는 추세인 반면에 적합한 적응증 및 시술 후 발생하는 합병증에 대한 논의는 아직 초기 단계에 있다. 저자들은 하행 대동맥 박리증으로 혈관내 스텐트 삽입술을 시행한 후, 원위부 흉복부 대동맥류가 커져 관류부전의 징후를 보인 환자를 수술적인 방법으로 교정하여 성공하였기에 이를 문헌 고찰과 더불어 보고하는 바이다.