• The Journal of Korean Academy of Prosthodontics
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• v.48 no.1
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• pp.28-40
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• 2010

Purpose: The aim of this retrospective study was to provide long-term data about the correlation between multifactorial local factors and the survival of implants. Material and methods: During 19 years (1991 to 2009), 2796 implants were placed in 879 patients. From dental charts and radiographs, the following data were collected: patient's age at implant placement, gender, implant system, surface, length, diameter, location of implant placement, bone quality, primary stability, type of prosthesis. The correlations between these data and implant survival were analyzed. Statistical analysis was performed using Kaplan-Meier survival analysis, Chi-square test, odds ratio. Results: 1. Among the 2796 implants, 150 implants failed that resulted in a cumulative survival rate of 94.64%. The cumulative survival rate of smooth surface implants (91.76%) was lower than rough surface implants (96.02%). 2. Anatomic location, implant surface, diameter of smooth surface implant, primary stability, type of prosthesis, patient's age and gender were significantly associated with implant survival (P < .05). 3. No significant difference in implant survival was found in relation to the following factors: implant length, bone quality, diameter of rough surface implants and type of rough surface according to implant manufacturer (P < .05). Conclusions: Local factors such as anatomic location, implant surface, diameter of smooth surface implant, primary stability and type of prosthesis have a significant effect on implant survival.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.4
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• pp.280-292
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• 2017

Hail is not a frequently occurring weather event, and there are even fewer reports of hail damages to forest stands. Since the 2000s, an increase in hail incidence has been documented in Europe and the United States. In Korea, severe hails occurred in Jeollanam-do province on May 31 and in Gyeongsangbuk-do province on June 1, 2017. Hail size was ranged from 0.5 to 5.0 cm in diameter in Jeollanam-do, and from 1.5 to 3.0 cm in Gyeongsangbuk-do. This study was aimed to analyze the hail damages to forests by species and topography based on damage-categorized maps created by using drones and aerial photographs, and to analyze relationships of the damages with meteorological factors. The total damaged forest area was 1,163.1ha in Jeollanam-do, and 2,942.3ha in Gyeongsangbuk-do. Among the 'severe' damaged area 326.7ha, 91% was distributed in Jeollanam-do, and concentrated in the city of Hwasun which covers 57.2% of the total 'severe' damaged area. The most heavily damaged species was Korean red pine(Pinus densiflora S. & Z.) followed by P. rigida. Most broad-leaved trees species including oaks were recovered without any dead trees found. Liliodendron tulipifera was the most severely damaged in terms of the rate of 'severe' degree individuals which are needed to be checked whether they will die or be recovered. Cause of the death of pines was considered as the combination of physical damage caused by the hail and long-lasting drought with high air temperature that occurred before and after the hail event. No pathogens and insects were found which might have affected to tree deaths. We suggested a dieback mechanism of the pine trees damaged by hail and drought.

• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.152-156
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• 2005

Background: Occlusive complications after arterial revascularization are difficult to treat and have high recurrence rate. This study was performed to establish an effective treatment modality and to evaluate the factors affecting the occlusive complications by analysis of clinical data. Material and Method: During the period of 5 years. 33 patients (55 reoperations) were studied at the Department of Thoracic and Cardiovascular Surgery, Pusan National University Hospital following 173 arterial revascularization surgeries. The clinical characteristics, operating methods, the time intervals of reoperation, used graft, and the results of treatment were evaluated retrospectively. Result: All the patients were men except one and the mean age was 63.5 years old. The mean time internal from first operation to reoperation was 11.9 months. The cause of arterial occlusive diseases were 28 atherosclerosis and 5 Burger's diseases, Associated diseases were Hypertension $(57.6\%)$, Diabetes mellitus $(33.3\%)$, heart failure $(18.2\%)$, and so on. The mean rate of reoperation was 1.67 times and the most common type of first operation was femoro-popliteal bypass grafting $(57.6\%)$. The graft that used revascularization surgery were 25 cases of PTFE and 6 case were Dacron. There was no statistical difference between two groups. The kinds of reoperations were thrombectomy in 20 cases, angioplasty 18 cases, re-bypass surgery in 13 cases, and lumbar sympathectomy in 4 cases. The results of reoperation were 15 cases of functional recovery, 7 cases of limb salvage, 5 cases of above-knee amputation. 3 cases of below-knee amputation and 3 deaths. Conclusion: The main cause of occlusive complications are occlusion of inflow or outflow artery. Treatments were different according to the first operation methods and graft used. The most frequent time of reoperation was within one year after the first operation. We believe that graft surveillance especially during the first year is very important factor in observing the patient. We can look forward to improving limb salvage rate to perform additional treatment such as radiological interventions and lumbar sympathectomy.

• Journal of Chest Surgery
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• v.39 no.4 s.261
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• pp.281-288
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• 2006

Background: Extracardiac pericardial-flap lateral tunnel Fontan operation has theoretical advantage of growth potentiality of the extracardiac tunnels. The mid-term results of this technique and morphologic change of the lateral tunnel were studied. Material and Method: Clinical data was reviewed in 42 patients who underwent extracardiac pericardial-flap lateral tunnel Fontan operation between November 1993 and December 2004. The age was $2.8{\pm}1.5$ years and the body weight was $12.3{\pm}3.2$ kg. Extracardiac tunnel was constructed using the pedicled pericardium with the base undetached. By reviewing the follow-up cardiac angiograms, the diameter and the cross-sectional area of the lateral tunnel was compared to those of inferior vena cava. Result: There were four operative mortality cases (9.8%) and the causes of death were low cardiac output for all four cases. Postoperatively, five patients had prolonged pleural effusion longer than two weeks and one patient required a permanent pacemaker due to complete heart block. Follow-up was possible in 37 patients and the follow up duration was $3.8{\pm}2.2$ years. During that period, one patient died, of upper gastrointestional bleeding combined with heart failure and one patient died a sudden death of unknown cause. Two patients required reoperation due to subaortic stenosis and anastomosis site stenosis between inferior vena cava and lateral tunnel. In one patient, bradyarrhythmia was anew but there was no thromboembolic complication. The lateral tunnel showed growth in proportion to the size of the inferior vena cava. Conclusion: Extracardiac pericardial-flap lateral tunnel Fontan operation is relatively simple and safe. The mid-term result was favorable and the extracardiac tunnel showed potential for growth.

• Journal of Chest Surgery
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• v.31 no.4
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• pp.339-345
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• 1998

Arrhythmias are common after cardiac surgery and are multifactorial. Intravenous magnesium administration reduces the frequency of ventricular arrhythmias in patient with symptomatic heart failure or acute myocardial infarction. This study was designed to evaluate the role of magnesium in preventing PVCs(premature ventricular contractions) occurred frequently after coronary artery bypass graft(CABG). 50 consecutive patients were prospectively entered into a randomized trial to determine the efficacy of postoperative magnesium therapy on the incidence of cardiac arrhythmias after elective coronary artery bypass graft. The patients underwent coronary angiography, echocardiography, electrocardiography and clinical laboratory study preoperatively. Continuous electrocardiographic monitoring was done and magnesium level was checked 0, 3, 6, 12, 18, 24, 36, 48, 60 and 72 hours postoperatively. Study group of 25 patients were given 4g of magnesium continuously over the first 24 hours and then 2g/24hours from 25 to 72 hours. The clinical characteristics of both groups were similar(p<0.05). The preoperative mean serum magnesium concentration was similar in both study group, 1.59mg/dl and control group, 1.71mg/dl. The mean postoperative serum magnesium concentration in study group elevated significantly over postoperative 12hours through 36hours(p<0.05). The postoperative mean serum magnesium concentration in control group declined and remained significantly depressed over immediate postoperation through 72hours. The mean serum magnesium concentration was significantly greater in the study group compared with the control group over postoperative 3hours through 72hours(p<0.05). There was a significant decrease in the incidence of arrhythmias such as PVCs(p<0.01) which might jeopardize hemodynamics. There were no recognized adverse effects of magnesium Administration. In conclusion, prophylactic magnesium administration seems to lessen the incidence and severity of rrhythmias after coponary artery bypass graft.

• Radiation Oncology Journal
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• v.23 no.2
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• pp.85-91
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• 2005

Purpose : This study was conducted to analyze treatment outcome and prognostic significance of World Health Organization (WHO)-defined thymic epithelial tumor (TET) subtype and to assess optimal radiation target volume in patients receiving surgery and adjuvant radiation therapy with TET. Materials and Methods: The record of 160 patients with TET, who received surgical resection at the Samsung medical Center, from December 1994 to June 2004, were reviewed. 99 patients were treated with postoperative radiation therapy (PORT). PORT was recommended when patients had more than one findings among suspicious Incomplete resection or positive resection margin or Wasaoka stage $II\~IV$ or WHO type $B2\~C$. PORT peformed to primary tumor bed only with a mean dose of 54 Gy. The prognostic factor and pattern of failure were analyzed retrospectively. Results : The overall survival rate at 5 years was $87.3\%$. Age (more than 60 years $77.8\%$, less than 60 years $91.1\%$; p=0.03), Wasaoka stage (I $92.2\%$, II $95.4\%$, III $82.1\%$, IV $57.5\%$; p=0.001), WHO tumor type (A-Bl $96.0\%$, B2-C $82.3\%$; p=0.001), Extent of resection (R0 resection $92.3\%$, R1 or 2 resection $72.6\%$, p=0.001) were the prognostic factors according to univariate analysis. But WHO tumor type was the only significant prognostic factor according to multivariate analysis. Recurrence was observed in 5 patients of 71 Masoka stage I-III patients who received grossly complete tumor removal (R0, R1 resection) and PORT to primary tumor bed. Mediastinal recurrence was observed In only one patients. There were no recurrence within irradiation field. Conclusion : WHO tumor type was the important prognostic factor to predict survival of patients with TET. This study suggest that PORT to only primary tumor bed was optimal. To avoid pleura- or pericardium-based recurrence, further study of effective chemotherapy should be investigated.

• Radiation Oncology Journal
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• v.22 no.4
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• pp.265-270
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• 2004

Purpose: To evaluate the effectiveness of postoperative radiation therapy in cervical cancer patients and define the prognostic factors to affect survival rates. Materials and Methods: Eighty one patients with cervical cancer who were treated with postoperative radiation therapy following surgery at our institution between May 1992 and April 2000 were retrospectivelv analyzed. Forty two patients had stage IB disease, 17 had stage IIA disease, and remaining 22 had stage IIB disease, respectively. Histological examination revealed 76 squamous cell carcinoma and 5 adenocarclnoma. Sixty one patients were noted to have stromal invasion greater than 8 mm and 20 patients were noted to have stromal invasion 7 mm or less. Sixteen patients had parametrial invasion and 65 patients did not. Positive vaginal resection margin was documented in only eight patients and positive lymphovascular invasion was in twelve patients. All of the patients were treated with external beam radiation therapy alone. Majority of the patients were treated with 4 field brick technique to encompass whole pelvis. Total of 5,500 cGy was delivered to the primary surgical tumor bed. Minimum follow up period was four years. Results: Actuarial disease free survival rates for entire group of the patients were 95% and 89% at 2 and 5 years, respectively Five year disease free survival rates for patients with stage IB, IIA, and IIB disease were 97%, 87% and 70%, respectivelv. Local recurrences were documented in 5 patients. Cumulative local failure rate at 3 years was 6% Five year disease free survival rates for patients with stromal invasion greater than 8 mm and 7 mm or less were 88% and 92%, respectively (p>0.05). Five year disease free survival rate for patients with parametrial invasion was significantly lower than those with no invasion (72% vs 92%, p<0.05). Also there was significantly lower survival in patients with positive vaginal resection margin, compared with patients with negative resection margin (64% vs 94%, p<0.05). However, lymphovascular invasion was not a statistically significant prognostic factor Parametrial invasion and positive surgical resection margins were noted to be significant prognostic factors. Conclusions: Postoperative radiation therapy appears to be beneficial in controlling local disease in cervical cancer patients with high pathologic risk factors. Parametrial invasion and positive resection margins were noted to be significant prognostic factors to affect survival and more effective treatment should be investigated in these patients.

• Radiation Oncology Journal
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• v.28 no.2
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• pp.85-90
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• 2010

Purpose: To evaluate the rate of tumor response, local control, and treatment-related complications after hypofractionated radiotherapy for recurrent hepatocelluar carcinoma (HCC) less than 5 cm in size. Materials and Methods: Among the HCC patients who were treated by radiotherapy (RT) between 2006 and 2007 after the failure of previous treatment, a total of 12 patients were treated with hypofractionated RT. The criteria for hypofractionated RT was as follows: 1) HCC less than 5 cm, 2) HCC not adjacent to a critical organ, 3) HCC without portal vein tumor thrombosis, and 4) less than 15% of normal liver volume that irradiated 50% of the prescribed dose. Hypofractionated RT was performed with 50 Gy delivered in 10 fractions, at a rate of 5 fractions per week. The evaluation of tumor response was determined by CT scans performed at 3 months after the cessation of RT, followed by the evaluation of toxicity by Common Terminology Criteria for Adverse Events version 3.0. The median follow-up period after radiotherapy was 18 months. Results: A complete response (CR) was achieved in 5 of 12 lesions (41.7%) at CT performed at 3 months after the cessation, whereas the overall complete response was observed in 7 of 12 cases (58.3%). In-field local control rate was sustained in 83.3% of patients. All patients developed intra-hepatic metastases except for 2 patients. The overall survival rate was 90.0% at 1 year and 67.5% at 2 years, respectively. Three patients developed Grade 1 nausea during RT and 1 patient showed a progression of ascites after RT. There was no grade 3 or greater treatment-related toxicities. Conclusion: Hypofractionated RT for small-sized HCC as a salvage therapy showed a 58.3% CR rate and 83.3% of local control. Fifty Gy administered in 10 fractions of partial liver irradiation is considered as a tolerable dose that does not cause severe complications.

• Radiation Oncology Journal
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• v.29 no.1
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• pp.44-52
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• 2011

Purpose: To evaluate the outcomes and prognostic factors of postoperative radiotherapy (PORT) for patients with pathological stage III non-small-cell lung cancer (NSCLC) at a single institution. Materials and Methods: From 2000 to 2007, 88 patients diagnosed as having pathologic stage III NSCLC after curative resection were treated with PORT. There were 80 patients with pathologic stage IIIA and eight patients with pathologic stage IIIB in the AJCC 6th staging system. The majority of patients (n=83) had pathologic N2 disease, and 56 patients had single station mediastinal LN metastasis. PORT was administered using conventional technique (n=76) or three-dimensional conformal technique (n=12). The median radiation dose was 54 Gy (range, 30.6 to 63 Gy). Thirty-six patients received chemotherapy. Radiation pneumonitis was graded by the Radiation Therapy Oncology Group system, and other treatment-related toxicities were assessed by CTCAE v 3.0. Results: Median survival was 54 months (range, 26 to 77 months). The 5-year overall survival (OS) and disease free survival (DFS) rates were 45% and 38%, respectively. The number of metastatic lymph nodes was associated with overall survival (hazard ratio, 1.037; p-value=0.040). The 5-year locoregional recurrence free survival (LRFS) and distant metastasis free survival (DMFS) rates were 88% and 48%, respectively. Multiple stations of mediastinal lymph node metastasis was associated with decreased DFS and DMFS rates (p-value=0.0014 and 0.0044, respectively). Fifty-one relapses occurred at the following sites: 10 loco-regional, 41 distant metastasis. Grade 2 radiation pneumonitis was seen in three patients, and symptoms were well tolerated with anti-tussive medication. Grade 2 radiation esophagitis was seen in 11 patients. There were no grade 3 or more severe complications associated with PORT. Conclusion: Our retrospective data show that PORT for pathological stage III NSCLC is a safe and feasible treatment and could improve loco-regional control. The number of metastatic lymph nodes and stations of mediastinal lymph node metastasis were analyzed as prognostic factors. Furthermore, efforts are needed to reduce distant metastasis, which is a major failure pattern of advanced stage NSCLC.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.425-431
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• 1998

Purpose : We retrospectively analyzed the impact of subpleural lesions of early stage non-small cell lung cancer on the patterns of failure to support selection of postoperative adjuvant therapy. Methods and Materials : The study included 91 patients who underwent surgery for early stage non-small cell lung cancer at Dong-A University Hospital from Dec 1990 to Sep 1996. Twenty five patients were excluded due to postoperative mortality (four patients, 4.4$\%$) and stage III (21 patients). Of 66 patients, 22 patients were subpleural lesions (15 patients in stage I, and seven patients in stage II). Postoperative adjuvant radiation therapy was given to seven patients with T2Nl disease. The median follow-up duration was 29.5 months (range; 8-84 months). Results : The overall survival rate was 69.5$\%$ at 3 years. For all patients who presented with (22 patients) and without (44 patients) subpleural lesions, 3-year overall survival rates were 35.5$\%$ and 84.6$\%$, respectively (p=0.0017). For stage I patients who presented with (15 patients) and without (29 patients) subpleural lesions, 3-year overall survival rates were 33.1$\%$ and 92.3$\%$, respectively (p=0.001). For stage II patients who presented with (7 patients) and without (15 patients) subpleural lesions, 3-year overall survival rates were 53.3$\%$ and 45.7$\%$, respectively (p=0.911). For patients with T2N0 disease (34 patients) who presented with (11 patients) and without (23 patients) subpleural lesions, 3-year overall survival rates were 27.3$\%$ and 90.3$\%$, respectively (p=0.009). Conclusion : These observations suggest that the subpleural lesion play an important role as a prognostic factor for early stage non-small cell lung cancer. Especially for T2N0 disease, patients with subpleural lesions showed significantly lower survival rate than those without that.