• Journal of Chest Surgery
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• 제26권1호
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• pp.24-31
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• 1993

The long term clinical results following valve replacement with Hancock and Carpentier-Edwards bioprostheses were compared between tow valve models and between tow groups totaling 249 patients who were discharged after valve replacement from 1976 to 1986. The two groups of patients were treated with nonrandomized fashion. Follow-up was 87% complete. Cummulative duration of follow-up was 1909 patient-years, with maximum follow-up duration of 15 years. The actuarial survival for 122 patients with Hancock valves was 95.2%[\ulcornerstandard deviation] and 84.4% after 5 and 10 years of follow-up, respectively. Comparable figures for 127 patients undergoing valve replacement with Carpentier-Edwards valves were 87.3% and 76.4%, respectively[p=NS]. The probability of freedom from structural valve deterioration after 5 and 10 years of follow-up was 97.2% and 60.6%, respectively, with Hancock valves and 97.2% and 55.7%, respectively, with Carpentier-Edwards valves[p=NS]. Considering all 249 patients, multivariate [Cox model] regression revealed that ejection fraction was only significant predictor of structural valve deterioration. The probability of freedom from thromboembolism after 5 and 10 years of follow-up was 91.3% and 86.4%, respectively, with Hancock valves and 94.2% and 82.5%, respectively, with Carpentier-Edwards valves[p=NS]. Hence more strict control of anticoagulation should be done on patients with left atrial factors. In summary, there were no significant differences in actuarial survival rate and major valve related complications between tow valve models. These results suggests that its use should be confined to older patients or patients with a contraindication of anticoagulation.

• Journal of Medicine and Life Science
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• 제20권2호
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• pp.73-82
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• 2023

Multiple studies have reported on unilateral axillary adenopathy following coronavirus disease 2019 (COVID-19) vaccination, which is currently recognized as a common finding. Here, we present a series of eight adult patients with reactive axillary lymphadenopathy following COVID-19 vaccination, in whom the follow-up ultrasonography (US) showed resolution of a previously noted unilateral axillary adenopathy. From March 2021 to March 2022, 2,599 consecutive women underwent breast US in Jeju National University Hospital. We identified 10 patients with unilateral axillary lymphadenopathy following COVID-19 vaccination detected on the breast US. The 10 patients were recommended for follow-up US. Two patients were lost to follow-up, whereas the remaining eight patients underwent follow-up US, in whom resolution of the unilateral axillary lymphadenopathy was noted. Radiologists should be aware of evolving guidelines for evaluating and managing axillary lymphadenopathy to avoid false positive biopsies. Recent studies on lymphadenopathy following COVID-19 vaccination show that a prolonged duration until resolution is often observed. Therefore, a follow-up US examination at least 12 weeks after vaccination may be reasonable. Furthermore, management guidelines should include a risk-stratified approach considering both vaccination timing and the patient's overall risk of metastatic disease.

• Journal of Korean Neurosurgical Society
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• 제42권4호
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• pp.265-270
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• 2007

Objective : The current literature implies that the use of short-segment pedicle screw fixation for spinal fractures is dangerous and inappropriate because of its high failure rate, but favorable results have been reported. The purpose of this study is to report the short term results of thoracolumbar burst and compression fractures treated with short-segment pedicle instrumentation. Methods : A retrospective review of all surgically managed thoracolumbar fractures during six years were performed. The 19 surgically managed patients were instrumented by the short-segment technique. Patients' charts, operation notes, preoperative and postoperative radiographs (sagittal index, sagittal plane kyphosis, anterior body compression, vertebral kyphosis, regional kyphosis), computed tomography scans, neurological findings (Frankel functional classification), and follow-up records up to 12-month follow-up were reviewed. Results : No patients showed an increase in neurological deficit. A statistically significant difference existed between the patients preoperative, postoperative and follow-up sagittal index, sagittal plane kyphosis, anterior body compression, vertebral kyphosis and regional kyphosis. One screw pullout resulted in kyphotic angulation, one screw was misplaced and one patient suffered angulation of the proximal segment on follow-up, but these findings were not related to the radiographic findings. Significant bending of screws or hardware breakage were not encountered. Conclusion : Although long term follow-up evaluation needs to verified, the short term follow-up results suggest a favorable outcome for short-segment instrumentation. When applied to patients with isolated spinal fractures who were cooperative with 3-4 months of spinal bracing, short-segment pedicle screw fixation using the posterior approach seems to provide satisfactory result.

• Hip & pelvis
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• 제35권1호
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• pp.40-46
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• 2023

Purpose: A variety of short Exeter stems designed specifically for use in performance of total hip arthroplasty (THA) in primary and revision settings have recently been introduced. Some have been used 'off label' for hip reconstruction. The aim of this study is to report clinical and radiological results from the Exeter V40 125 mm stem in performance of primary THA and revision THA. Materials and Methods: This study had a retrospective design. Insertion of 58 (24 primary, 34 revision) Exeter V40 125 mm stems was performed between 2015 and 2017. The minimum follow-up period was two years. Assessment of the Oxford hip score (OHS), EuroQol-5 Dimension (EQ-5D), and radiological follow-up was performed at one and two years. Results: In the primary group, the preoperative, mean OHS was 13.29. The mean OHS was 32.86 and 23.39 at one-year and two-year post-surgery, respectively. The mean EQ-5D-3L scores were at 0.14, 0.59, and 0.35, preoperatively, at one-year follow-up and two-year follow-up, respectively. In the revision group, the mean preoperative OHS was 19.41. The mean OHS was 30.55 and 26.05 at one-year and two-year post-surgery, respectively. The mean EQ-5D-3L scores were 0.33, 0.61, and 0.48 preoperatively, at one-year follow-up and two-year follow-up, respectively. No progressive or new radiolucent lines were observed around any stem at the time of the final follow-up in all patients in both groups. Conclusion: Encouraging results regarding use of Exeter V40 125 mm stems have been reported up to two years following surgery in primary and revision THA settings.

• Korean Journal of Radiology
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• 제21권9호
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• pp.1027-1035
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• 2020

Objective: To assess the appropriate follow-up interval, and rate and timepoint of cancer detection in women with Breast Imaging Reporting and Data System (BI-RADS) 3 lesions on screening ultrasonography (US) according to the type of institution. Materials and Methods: A total of 1451 asymptomatic women who had negative or benign findings on screening mammogram, BI-RADS 3 assessment on screening US, and at least 6 months of follow-up were included. The median follow-up interval was 30.8 months (range, 6.8-52.9 months). The cancer detection rate, cancer detection timepoint, risk factors, and clinicopathological characteristics were compared between the screening and tertiary centers. Nominal variables were compared using the chi-square or Fisher's exact test and continuous variables were compared using the independent t test or Mann-Whitney U test. Results: In 1451 women, 19 cancers (1.3%) were detected; two (0.1%) were diagnosed at 6 months and 17 (1.2%) were diagnosed after 12.3 months. The malignancy rates were both 1.3% in the screening (9 of 699) and tertiary (10 of 752) centers. In the screening center, all nine cancers were invasive cancers and diagnosed after 12.3 months. In the tertiary center, two were ductal carcinomas in situ and eight were invasive cancers. Two of the invasive cancers were diagnosed at 6 months and the remaining eight cancers newly developed after 13.1 months. Conclusion: One-year follow-up rather than 6-month follow-up may be suitable for BI-RADS 3 lesions on screening US found in screening centers. However, more caution is needed regarding similar findings in tertiary centers where 6-month follow-up may be more appropriate.

• 한국초등과학교육학회지:초등과학교육
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• 제35권1호
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• pp.123-135
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• 2016

Interest is one of the important factors in science education. The purpose of this study was to investigate factors affecting the follow-up interest of elementary school students on topics of 'Small Organisms' World'. The follow-up interests of the students on the topic were grouped into three categories; the developed-expanded-deepened (EDD), the simply expanded and maintained (SEM), and the stoped or decreased (SD) types. Each types had specific distinguishing features. Through the examination of students' responses and the in-depth interviews, the factors affecting on the follow-up interests of the students were analyzed. The factors were classified into two types of the external factor and the internal one. While the external factors were mainly related to the instructional materials used in science class and teaching methods, the internal factors were related to the desire for knowing, prior knowledge, students' experience and attitude toward the topics of science. In relation to the types of the follow-up interests, these factors were affected by different causes. The EDD type was most affected by internal factors, such as desire for knowing and prior knowledge. The SEM type was shown to be most affected by external factors, such as instructional materials. The SD type was mainly influenced by external factors, such as teaching methods. From the analysis of internal factors, it was revealed that the attitude and the prior knowledge about the topic are related with the follow-up interests. There was a positive relationship between the levels of science attitude and science knowledge. The students who had EDD type had a higher level of attitude and knowledge. However, there were some students who had higher level of scientific knowledge with SD type. The results of in-depth interviews showed that they were influenced by negative perceptions about science and stress on their grades. In conclusion, each follow-up interest type were caused by the external factors contained in the processes of the science class and the internal ones associated with the individual features and were influenced by the science class. So, the teacher should help the students be able to have the EDD type of follow-up interest which is persisted even after the completion of the science curriculum. For this, when the teachers design science curriculum and plan lesson, they should consider both internal and external factors significantly influencing the students' follow-up interests.

• 대한족부족관절학회지
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• 제11권2호
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• pp.154-159
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• 2007

Purpose: The purpose of the present study is to evaluate the proximal metatarsal chevron osteotomy outcomes for moderate to severe hallux valgus more than seven year follow up. Materials and Methods: Between 1996 and 1998, hallux valgus 61 cases were evaluated. The follow up period was more than seven years. The clinical review analyzed by the hallux metatarsophalangeal-interphalangeal scale of the American Orthopedic Foot and Ankle Society, radiologic review by the hallux valgus angle, first and second intermetatarsal angle. Complication also evaluated. Results: Clinically, preoperative AOFAS score was average 43 points (range; $16{\sim}60$ points) which significantly improved to 88 points (range; $61{\sim}100$ points) at last follow up periods. Radiologically, the mean preoperative, postoperative, last follow up hallux valgus angle was $34^{\circ}$, $5.2^{\circ}$, $10.9^{\circ}$. The mean preoperative, postoperative, last follow up intermetatarsal angle was $15.3^{\circ}$, $3.3^{\circ}$, $5.3^{\circ}$. Postoperative angle change were no statistical significance (p>0.05). Complication were hallux varus 6 cases, metatarsophalangeal joint arthritis 2 cases, recurrence 1 case. Conclusion: Proximal metatarsal chevron osteotomy shows satisfactory outcome for moderate to severe hallux valgus more than seven year follow up.

• 대한기계학회논문집A
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• 제36권7호
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• pp.759-768
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• 2012

본 논문은 이차하중을 받는 고온 구조물의 $C(t)$-적분 예측을 위한 탄성추종 계수를 결정하는 기법을 제시한다. 이차하중을 받는 구조물의 과도 크리프 상태의 크리프 균열 진전률은 $C(t)$를 이용하여 정량화할 수 있다. 이차하중을 받는 구조물에서 발생할 수 있는 탄성추종 현상은 응력 완화를 방해하므로, 탄성추종 현상이 증가하면 $C(t)$와 크리프 균열 진전률이 증가한다. Ainsworth 와 Dean 은 참조응력법에 기반하여 $C(t)$ 예측식을 제시하였는데, 이 식을 계산하기 위해서는 탄성추종 계수가 필요하다. 본 연구에서 고온 균열 구조물의 크리프에 의한 탄성추종 계수를 결정하는 방법을 제시하였다. 소성-크리프 유사성을 이용하여 탄소성 유한요소해석으로 크리프 탄성추종 계수를 결정할 수 있다. 유한요소해석을 이용하여 이 탄성추종 계수 결정법을 검증하였다.

• 한국항해학회지
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• 제5권2호
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• pp.49-58
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• 1981

One of the main purposes of the marine gyrocompass follow-up system is to preserve the sensitive part from the wandering error due to the frictional or torsional torque around the vertical axis. This error can be diminished through the rapid follow-up action, which minimizes the relative azimuthal angular displacement between the sensitive and follow-up parts and shortens the duration of the same displacement. But an excessive rapidity of the follow-up action would result in a sustained oscillation to the system. Therefore, to design a new type of the follow-up system, the theoretical annlysis of the problems concerned should be studied systematically by introducing the control theory. This paper suggest a concrete procedure for the optimal adjustment of the gyrocompass follow-up system, utilizing the mathematic model and the stability informations formerly investiaged by the author. For theoptimal determination of the adjustable paramfter K, the performance index(P.I.), ITSE(Intergral of the Time multiplied by the Squared Error) is proposed, namely, P.I. = $\int_{0}^{\infty} t \cdot e^{2}(t)dt$ where t is time and e(t) means control error. Then, the optimal parameter minimizing the performance index is calculated by means of Parseval's theorem and numerical computation, and the validity of the obtained optimal value of the parameter Ka is examined and confirmed through the simulations and experiments. By using, the proposed method, the optimal adjustment can be performed deterministically. But, this can not be expected in the conventional frequency domain analysis. While the Mps of the original system vary to the extent of from 0.98 to 46.27, Mp of the optimal system is evaluated as 1.1 which satisfies the generally accepted frequency domain specification.

• Clinics in Shoulder and Elbow
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• 제24권3호
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• pp.166-171
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• 2021

Background: This study aims to compare the clinical outcomes of steroid injections during the rehabilitation period after arthroscopic rotator cuff repair (ACRC). Methods: Among patients who underwent ARCR, 117 patients who met the inclusion and exclusion criteria were enrolled. Pain and range of motion (ROM) recovery at the 3-, 6-, and 24-month follow-up visits and functional outcome at the 24-month follow-up were compared between 45 patients who received ultrasound-guided subacromial steroid injection at postoperative week 4 or 6 and 72 patients who did not. Functional outcome was assessed using the American Shoulder and Elbow Surgeons (ASES) score and Constant score. Healing of the repaired tendon and retear were observed at the 6-month follow-up via magnetic resonance imaging (MRI) or computed tomography (CT) arthrography. Results: At the 3-month follow-up, the steroid injection group showed lower visual analog scale scores than the control group (p<0.05) and showed faster recovery of forward flexion and internal rotation (p<0.05). From the 6-month follow-up, the two groups did not show differences in pain and ROM, and the ASES score and Constant score also did not significantly differ at the 24-month follow-up. The two groups did not differ in retear rate as determined by MRI or CT arthrography at the 6-month follow-up. Conclusions: This study demonstrated that ultrasound-guided subacromial steroid injection at 4 or 6 weeks after ARCR leads to quick pain reduction and ROM recovery until 3 months after surgery. Therefore, subacromial steroid injection is speculated to be an effective and relatively safe method to assist rehabilitation.