• Journal of Korean Neurosurgical Society
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• 제61권2호
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• pp.212-218
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• 2018

Objective : Surgical clipping of the cerebral aenurysm is considered as a standard therapy with endovascular coil embolization. The surgical clipping is known to be superior to the endovascular coil embolization in terms of recurrent rate. However, a recurrent aneurysm which is initially treated by surgical clipping is difficult to handle. The purpose of this study was to research the management of the recurrent cerebral aneurysm after a surgical clipping and how to overcome them. Methods : From January 1996 to December 2015, medical records and radiologic findings of 14 patients with recurrent aneurysm after surgical clipping were reviewed retrospectively. Detailed case-by-case analysis was performed based on preoperative, postoperative and follow-up radiologic examinations and operative findings. All clinical variables including age, sex, aneurysm size and location, type and number of applied clips, prognosis, and time to recurrence are evaluated. All patients are classified by causes of the recurrence. Possible risk factors that could contribute to those causes and overcoming ways are comprehensively discussed. Results : All recurrent aneurysms after surgical clipping were 14 of 2364 (0.5%). Three cases were males and 11 cases were females. Mean age was 52.3. At first treatment, nine cases were ruptured aneurysms, four cases were unruptured aneurysms, and one case was unknown. Locations of recurrent aneurysm were determined; anterior communicating artery (A-com) (n=7), posterior communicating artery (P-com) (n=3), middle cerebral artery (n=2), anterior cerebral artery (n=1) and basilar artery (n=1). As treatment of the recurrence, 11 cases were treated by surgical clipping and three cases were treated by endovascular coil embolization. Three cases of all 14 cases occurred in a month after the initial treatment. Eleven cases occurred after a longer interval, and three of them occurred after 15 years. By analyzing radiographs and operative findings, several main causes of the recurrent cerebral aneurysm were found. One case was incomplete clipping, five cases were clip slippage, and eight cases were fragility of vessel wall near the clip edge. Conclusion : This study revealed main causes of the recurrent aneurysm and contributing risk factors to be controlled. To manage those risk factors and ultimately prevent the recurrent aneurysm, neurosurgeons have to be careful in the technical aspect during surgery for a complete clipping without a slippage. Even in a perfect surgery, an aneurysm may recur at the clip site due to a hemodynamic change over years. Therefore, all patients must be followed up by imaging for a long period of time.

• Korean Journal of Radiology
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• 제23권11호
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• pp.1078-1088
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• 2022

Objective: To develop and validate a model using radiomics features from apparent diffusion coefficient (ADC) map to diagnose local tumor recurrence in head and neck squamous cell carcinoma (HNSCC). Materials and Methods: This retrospective study included 285 patients (mean age ± standard deviation, 62 ± 12 years; 220 male, 77.2%), including 215 for training (n = 161) and internal validation (n = 54) and 70 others for external validation, with newly developed contrast-enhancing lesions at the primary cancer site on the surveillance MRI following definitive treatment of HNSCC between January 2014 and October 2019. Of the 215 and 70 patients, 127 and 34, respectively, had local tumor recurrence. Radiomics models using radiomics scores were created separately for T2-weighted imaging (T2WI), contrast-enhanced T1-weighted imaging (CE-T1WI), and ADC maps using non-zero coefficients from the least absolute shrinkage and selection operator in the training set. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic performance of each radiomics score and known clinical parameter (age, sex, and clinical stage) in the internal and external validation sets. Results: Five radiomics features from T2WI, six from CE-T1WI, and nine from ADC maps were selected and used to develop the respective radiomics models. The area under ROC curve (AUROC) of ADC radiomics score was 0.76 (95% confidence interval [CI], 0.62-0.89) and 0.77 (95% CI, 0.65-0.88) in the internal and external validation sets, respectively. These were significantly higher than the AUROC values of T2WI (0.53 [95% CI, 0.40-0.67], p = 0.006), CE-T1WI (0.53 [95% CI, 0.40-0.67], p = 0.012), and clinical parameters (0.53 [95% CI, 0.39-0.67], p = 0.021) in the external validation set. Conclusion: The radiomics model using ADC maps exhibited higher diagnostic performance than those of the radiomics models using T2WI or CE-T1WI and clinical parameters in the diagnosis of local tumor recurrence in HNSCC following definitive treatment.

• Radiation Oncology Journal
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• 제17권3호
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• pp.217-222
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• 1999

목적 : 근치적 수술 후 국소재발한 자궁경부암 치료에 있어서 방사선치료의 역할 및 치료 결과에 영향을 미치는 인자들을 분석하고자 본 연구를 시행하였다. 대상 및 방법 : 1983년 10월부터 1996년 7월까지 가톨릭대학교 강남성모병원 치료방사선과에서 FlGO병기 I, II 자궁 경부암의 근치적 수술 후 국소재발한 환자 중 방사선치료를 받았던 53명을 대상으로 치료결과에 대한 후향적 분석을 시행하였다. 환자의 연령은 33세에서 69세 사이(중앙값 53세)였으며, 병리조직학적 분류로는 편평상피암이 45명($84.9\%$), 선암이 7명($13.2\%$), 편평상피선암이 1명($1.9\%$)이었다. 수술 후 재발까지의 기간은 2 개월에서 25년 사이로 평균 34.4 개월이었다. 재발한 병소의 위치에 따라서 질 절제단(vaginal stump)이 41명($77.4\%$), 골반외벽(pelvic side wall)이 12명($22.6\%$)이었고, 재발한 병소를 크기에 따라 나누었을 때 3cm 이하인 경우가 43명($81.1\%$), 3 cm보다 큰 경우가 10명($18.9\%$)이었다. 방사선치료는 대부분 환자에서 전골반에 외부 방사선치료를 하루 1.8 Gy의 양으로 주 5회씩 치료하여 $46.~50.4$ Gy까지 치료한 후, 18명($34\%$)에서는 병소부위에 외 부방사선치료를, 24명($45.3\%$)의 환자에서는 강내근접치료를 각각 추가하여 총방사선량 $46.8\~111$ Gy(중앙값 70.2 Gy)까지 치료하였다. 추적조사 기간은 2 개월에서 153 개월 사이(중앙값 35 개월)였다. 결과 : 방사선치료후 초기관해율은 $66\%$ (35/53)이었고, 이 중 6명($17.1\%$)에서 방사선치료후 7 개월에서 116 개월사이(평균 47.7 개월)에 다시 국소재발하여 전체환자의 국소재발율은 $45.3\%$였다. 전체환자의 5년 생존율은 $78.9\%$였으며, 원격 전이율은 $10\%$ (5/50)로 발생부위별로는 폐 2명, 뇌 1명, 원격 임파절 2명이었다. 생존율에 영향을 미치는 인자로는 수술 후 재발까지의 기간(p=0.0055), 재발 병소의 크기(p=0.0039), 방사선치료에 대한 초기반응 유무(p=0.0428) 등으로 분석되었으며, 그 외에 초기 병기, 연령, 조직학적 유형, 재발병소의 위치, 방사선 조사량, 약물치료 유무 등은 영향이 없는 것으로 나타났다(p>0.05). 방사선치료의 합병증은 10명($20\%$)에서 발생하였으나, 대부분 경미하거나 중등도의 하부위장관 또는 비뇨기계, 피부합병증이었고, 한명이 강내 방사선치료 직후 폐전색증으로 사망하였다. 결론 : 근치적 수술 후 국소재발한 자궁경부암 환자에서 방사선치료는 매우 효과적이며, 수술 후 재발까지의 기간, 재발병소의 크기, 방사선치료에 대한 초기반응 등이 예후에 영향을 미치는 인자로 나타났다.

• Journal of Korean Neurosurgical Society
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• 제44권4호
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• pp.199-204
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• 2008

Objective : This study was designed to compare the efficacy of micro-vascular decompression (MVD) and Gamma knife radiosurgery (GKRS) for elderly idiopathic trigeminal neuralgia patients by analyzing the clinical outcome. Methods : In the past 10 years, 27 elderly patients were treated with MVD while 18 patients were treated with GKRS (>65-years-old). We reviewed their clinical characteristics and clinical courses after treatment as well as the treatment outcomes. For patients who were treated with MVD, additional treatment methods such as rhizotomy were combined in some areas. In GKRS, we radiated the root entry zone (REZ) with the mean maximum dose of 77.8 (70-84.3) Gy and one 4 mm collimator. Results : The mean age was 68.1 years for MVD, and 71.1 years for GKS group. The average time interval between first presenting symptom and surgery was 84.1 (1-361) months, and 51.4 (1-120) months, respectively. The mean follow-up period after the surgery was 35.9 months for MVD, and 33.1 months for GKRS. According to Pain Intensity Scale, MVD group showed better prognosis with 17 (63%) cases in grade I-II versus 10 (55.6%) cases in GKRS group after the treatment. The pain recurrence rate during follow up did not show much difference with 3 (11.1%) in MVD, and 2 (11.1%) in GKRS. After the treatment, 2 cases of facial numbness, and 1 case each of herpes zoster, cerebrospinal fluid (CSF) leakage, hearing disturbance, and subdural hematoma occurred in MVD Group. In GKRS, there was 1 (5.6%) case of dysesthesia but was not permanent. Three cases were retreated by GKRS but the prognosis was not as good as when the surgery was used as primary treatment, with 1 case of grade I-II, and 1 case of recurrence. The maximal relieve of pain was seen just after surgery in MVD group, and 1 year after treatment in GKRS group. Conclusion : For trigeminal neuralgia patients with advanced age, MVD showed advantages in immediately relieving the pain. However, in overall, GKRS was preferable, despite the delayed pain relief, due to the lower rate of surgical complications that arise owing to the old age.

• Journal of Chest Surgery
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• 제34권8호
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• pp.604-610
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• 2001

배경: Stanford 제A형(type A) 대동맥 박리증은 상행대동맥이나 대동맥궁의 인조혈관 치환 수술 후에도 남은 대동맥의 가강이 확장되거나 파열의 가능성이 있기 때문에 철저한 추적관리가 필요하다. 연세대학교 세브란스병원에서는 1984년 6월부터 2000년 3월까지 Stanford 제A형의 대동맥박리 수술이 124예 있었다. 수술 후 가강의 확장이나 파열로 재수술한 6예에서 Marfan 증후군과의 관련성 등 원인을 조사하고 재수술의 방법과 결과, 재수술의 위험을 줄일 수 있는 방법 등을 알아보고자 한다. 대상 및 방법: 처음 대동맥 박리로 수술시급성인 경우가 4예 만성이 2예였으며 이중 3예가 Marfan 증후군이였다. 1예를 제외한 모든 환자에서 상행대동맥내에 내막파열이 있어 대동맥판막의 폐쇄부전의 정도에 따라 상행대동맥 인조혈관 치한수술(2례) 또는 Bentall 수술을 시행하였으며(3례) 1예는 여러 개의 가강과의 연결부위가 있는 만성 박리 환자로 Bentall 수술과 더불어 대동맥궁까지 인조혈관으로 치환을 하였다. 재수술은 평균 67.6개월(4개월-14년4개월) 후에 시행하였는데 1예는 만성 하행대동맥 박리 및 동맥류로 1예는 염증성 가성동맥류로 나머지 4예는 급성대동맥 박리로 재수술을 시행하였다. 수술은 하행흉부대동맥만을 치환한 경우가 1예, Hemiarch로 시행한 경우가 1예 그리고 나머지 4예는 원위부 상행대동맥에서 대동맥궁을 포함하여 근위부 또는 중간부위의 하행 흉부대동맥까지 인조혈관으로 치환하였다. 결과: 전체 124예 중 Marfan 증후군이 동반된 경우는 18예였다.

• Korean Journal of Radiology
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• 제23권2호
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• pp.159-171
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• 2022

Objective: This study aimed to investigate the impact of baseline values and temporal changes in body composition parameters, including skeletal muscle index (SMI) and visceral adipose tissue area (VAT), measured using serial computed tomography (CT) imaging on the prognosis of operable breast cancers in Asian patients. Materials and Methods: This study retrospectively included 627 Asian female (mean age ± standard deviation [SD], 53.6 ± 8.3 years) who underwent surgery for stage I-III breast cancer between January 2011 and September 2012. Body composition parameters, including SMI and VAT, were semi-automatically calculated on baseline abdominal CT at the time of diagnosis and follow-up CT for post-treatment surveillance. Serial changes in SMI and VAT were calculated as the delta values. Multivariable Cox regression analysis was used to evaluate the association of baseline and delta SMI and VAT values with disease-free survival. Results: Among 627 patients, 56 patients (9.2%) had breast cancer recurrence after a median of 40.5 months. The mean value ± SD of the baseline SMI and baseline VAT were 43.7 ± 5.8 cm²/m² and 72.0 ± 46.0 cm², respectively. The mean value of the delta SMI was -0.9 cm²/m² and the delta VAT was 0.5 cm². The baseline SMI and VAT were not significantly associated with disease-free survival (adjusted hazard ratio [HR], 0.983; 95% confidence interval [CI], 0.937-1.031; p = 0.475 and adjusted HR, 1.001; 95% CI, 0.995-1.006; p = 0.751, respectively). The delta SMI and VAT were also not significantly associated with disease-free survival (adjusted HR, 0.894; 95% CI, 0.766-1.043; p = 0.155 and adjusted HR, 1.001; 95% CI, 0.989-1.014; p = 0.848, respectively). Conclusion: Our study revealed that baseline and early temporal changes in SMI and VAT were not independent prognostic factors regarding disease-free survival in Asian patients undergoing surgery for breast cancer.

• Wind and Structures
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• 제3권3호
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• pp.177-191
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• 2000

This paper presents an approach for evaluating directionality effects for both wind speeds and wind loads in hurricane-prone regions. The focus of this study is on directional wind loads on low-rise structures. Using event-based simulation, hurricane directionality effects are determined for an open-terrain condition at various locations in the southeastern United States. The wind speed (or wind load) directionality factor, defined as the ratio of the N-year mean recurrence interval (MRI) wind speed (or wind load) in each direction to the non-directional N-year MRI wind speed (or wind load), is less than one but increases toward unity with increasing MRI. Thus, the degree of conservatism that results from neglecting directionality effects decreases with increasing MRI. It may be desirable to account for local exposure effects (siting effects such as shielding, orientation, etc.) in design. To account for these effects in a directionality adjustment, the factor described above for open terrain would need to be transformed to other terrains/exposures. A "local" directionality factor, therefore, must effectively combine these two adjustments (event directionality and siting or local exposure directionality). By also considering the direction-specific aerodynamic coefficient, a direction-dependent wind load can be evaluated. While the data necessary to make predictions of directional wind loads may not routinely be available in the case of low-rise structures, the concept is discussed and illustrated in this paper.

• Journal of Gastric Cancer
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• 제10권4호
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• pp.219-225
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• 2010

Purpose: The long-term survival rate of gastric cancer patients after surgery has recently increased as a result of making an early diagnosis of gastric cancer. Therefore, the incidence of remnant gastric cancer is increasing. This study was performed to evaluate the clinicopathological characteristics and prognosis of patients with remnant gastric cancer. Materials and Methods: From January 2005 to December 2009, twenty-nine patients with remnant gastric cancer and who underwent surgery at Pusan National University Hospital were enrolled in this study. We retrospectively reviewed and analyzed their medical records. We also divided them into two groups: the remnant gastric cancer (RGC)-B group (first operation for benign disease) and the RGC-M group (first operation for malignant disease). Results: The RGC-B group included ten patients and the RGC-M group included nineteen patients. The mean interval between the first and second operations was 17 years. The curative resection rate was 93.1% (27/29). The postoperative complication rate was 20.7% (6/29) and there was no perioperative mortality. Ten (37%) of twenty-seven patients experienced recurrence after curative resection and eight patients (27.6%) expired due to aggravation of remnant stomach cancer. An advanced TNM stage and non-curative resection were the negative prognostic factors for survival for patients with remnant stomach cancer (P=0.0453 and P<0.001). The RGC-M group showed a shorter interval (P<0.001) and the RGC-B group had more advanced TNM stage (P=0.003). Conclusions: Long-term follow-up should be considered not only for patients who undergo an operation for malignant disease, but also for the patients who underwent an operation for benign disease. When remnant gastric cancer is diagnosed, curative resection is essential to improve the survival.

• 한국환경과학회지
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• 제20권5호
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• pp.555-564
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• 2011

This study examines the potential restoration of abandoned channels of the Mangyeong River in South Korea. To analyze the morphological changes and equilibrium conditions, a flow duration analysis was performed to obtain the discharge of 255 m3/s with a recurrence interval of 1.5 year. It is a gravel-bed stream with a median bed diameter of 36 mm. The reach-averaged results using HEC-RAS showed that the top width is 244 m, the mean flow depth is 1.11 m, the width/depth ratio is very high at 277, the channel velocity is 1.18 m/s, and the Froude number is also high at 0.42. The hydraulic parameters vary in the vicinity of the three sills which control the bed elevation. The total sediment load is 6,500 tons per day and the equivalent sediment concentration is 240 mg/l. The Engelund-Hansen method was closer to the field measurements than any other method. The bed material coarser than 33 mm will not move. The methods of Julien-Wargadalam and Lacey gave an equilibrium channel width of 83 m and 77 m respectively, which demonstrates that the Mangyeong River is currently very wide and shallow. The planform geometry for the Mangyeong River is definitely straight with a sinuosity as low as 1.03. The thalweg and mean bed elevation profiles were analyzed using field measurements in 1976, 1993 and 2009. The measured profiles indicated that the channel has degraded about 2 m since 1976. The coarse gravel material and large width-depth ratio increase the stability of the bed material in this reach.

• Archives of Plastic Surgery
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• 제46권5호
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• pp.449-454
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• 2019

Background Most patients with head and neck cancer successfully undergo oncologic resection followed by free or local flap reconstruction, depending on the tumor's size and location. Despite effective curative resection and reconstruction, head and neck cancer patients still face a high risk of recurrence and the possibility of a second primary cancer. Moreover, surgeons hesitate to perform sequential reconstruction following curative resection for several reasons. Few large-scale studies on this subject are available. Therefore, we retrospectively evaluated the outcome of sequential head and neck reconstruction to determine the possible risks. Methods In total, 467 patients underwent head and neck reconstruction following cancer resection at our center from 2008 to 2017. Of these cases, we retrospectively reviewed the demographic and clinical features of 58 who had sequential head and neck reconstruction following resection of recurrent cancer. Results Our study included 43 males (74.1%) and 15 females (25.9%). The mean age at the initial operation was $55.4{\pm}15.3years$, while the mean age at the most recent operation was $59.0{\pm}14.3years$. The interval between the first and second operations was $49.2{\pm}62.4months$. Twelve patients (20.7%) underwent surgery on the tongue, and 12 (20.7%) had procedures on the oropharynx. Thirty-four patients (58.6%) received a sequential free flap reconstruction, and 24 patients (41.4%) were treated using locoregional flaps. No cases of flap failure occurred. Conclusions Our findings suggest that patients who need additional operations with recurrent head and neck cancer could optimally benefit from sequential curative resections and reconstructions.