A lithium-ion battery is a rechargeable battery that uses the reversible reduction of lithium ions to store energy and is the predominant battery type in many industrial and consumer electronics. The lithium-ion batteries are essential to ensure they operate safely. We conducted an exposure assessment five days after a fire in a battery-testing facility. We assessed some of the potentially hazardous materials after a lithium-ion battery fire. We sampled total suspended particles, hydrogen fluoride, and lithium with real-time monitoring of particulate matter (PM) 1, 2.5, and 10 micrometers (μm). The area sampling results indicated that primary potential hazardous materials such as dust, hydrogen fluoride, and lithium were below the recommended limits suggested by the Korean Ministry of Labor and the American Conference of Governmental Industrial Hygienists Threshold Limit Values. Based on our assessment, workers were allowed to return to work.

Purpose: Renal tumors account for approximately 7% of all childhood cancers. These include Wilms tumor (WT), clear cell sarcoma of the kidney (CCSK), malignant rhabdoid tumor of the kidney (MRTK), renal cell carcinoma (RCC), congenital mesoblastic nephroma (CMN) and other rare tumors. We investigated the epidemiology of pediatric renal tumors in Korea. Materials and Methods: From January 2001 to December 2015, data of pediatric patients (0–18 years) newly-diagnosed with renal tumors at 26 hospitals were retrospectively analyzed. Results: Among 439 patients (male, 240), the most common tumor was WT (n=342, 77.9%), followed by RCC (n=36, 8.2%), CCSK (n=24, 5.5%), MRTK (n=16, 3.6%), CMN (n=12, 2.7%), and others (n=9, 2.1%). Median age at diagnosis was 27.1 months (range 0-225.5) and median follow-up duration was 88.5 months (range 0-211.6). Overall, 32 patients died, of whom 17, 11, 1, and 3 died of relapse, progressive disease, second malignant neoplasm, and treatment-related mortality. Five-year overall survival and event free survival were 97.2% and 84.8% in WT, 90.6% and 82.1% in RCC, 81.1% and 63.6% in CCSK, 60.3% and 56.2% in MRTK, and 100% and 91.7% in CMN, respectively (p < 0.001). Conclusion The pediatric renal tumor types in Korea are similar to those previously reported in other countries. WT accounted for a large proportion and survival was excellent. Non-Wilms renal tumors included a variety of tumors and showed inferior outcome, especially MRTK. Further efforts are necessary to optimize the treatment and analyze the genetic characteristics of pediatric renal tumors in Korea.

Purpose: This study aimed to identify levels of perception and performance of end-oflife care among nurses and to investigate correlations between perception and performance. Methods: This cross-sectional descriptive survey included 321 nurses from a tertiary hospital in Seoul, Korea. The participants had at least 6 months of work experience and had been involved in end-of-life care at least once, in either ward or intensive care unit settings.A structured questionnaire was utilized to assess their perception and performance of endof-life care. Results: The mean score for perception of end-of-life care was 3.23±0.34, while the score for performance of end-of-life care was 3.08±0.34. There was a significant positive correlation between nurses’ perception of end-of-life care and their performance in this area (r=0.78, P＜0.001). Conclusion It is necessary to change perceptions regarding end-of-life care and to develop systematic and standardized education programs including content such as assessing the hydration status of dying patients, evaluating mental aspects such as suicidal ideation, and providing spiritual care for nurses working in end-of-life departments.

Background: Increasing longevity has caused the very old population to become the fastest-growing segment. The number of centenarians (over 100 years old) is increasing rapidly. Fractures in the elderly lead to excessive medical costs and decreased quality of life with socioeconomic burdens. However, little research has thoroughly examined the functional outcomes and mortality of hip fractures in centenarians. Methods: This is a retrospective observational study. Sixty-eight centenarian hip fracture patients were admitted to the 10 institutions from February 2004 to December 2019. Fifty-six patients with 1-year follow-up were finally included. The following data were obtained: sex, age, body mass index, Charlson comorbidity index value on the operation day, Koval’s classification for ambulatory ability, type of fracture, the time interval from trauma to surgery, American Society of Anesthesiologists grade, surgery-related complications, and duration of hospital stay. Postoperative Koval’s classification (at 1 year after surgery) and information about death were also collected. Multivariate analysis was performed to analyze the risk factors affecting mortality 1 year after surgery. Results: Mortality rates were 26.8% at 6 months and 39.3% at 1 year. The 90-day mortality was 19.6%, and one of them (2.1%) died in the hospital. The 1-year mortality rates for the community ambulatory and non-community ambulatory groups were 29% and 52%, respectively. Only 9 (16.1%) were able to walk outdoors 1 year after surgery. The remaining 47 patients (83.9%) had to stay indoors after surgery. Multivariate analysis demonstrated that the pre-injury ambulatory level (adjusted hazard ratio, 2.884; p = 0.034) was associated with the risk of mortality. Conclusions We report a 1-year mortality rate of 39.3% in centenarian patients with hip fractures. The risk factor for mortality was the pre-injury ambulatory status. This could be an important consideration in the planning of treatment for centenarian hip fracture patients.

Background: Osteonecrosis of the femoral head (ONFH) involves young or middle-aged adults, and its incidence is increasing along with increasing use of steroids in the management of organ transplantation and adjuvant therapy for malignant neoplasms. To date, no pharmacological agent has been proven to prevent or retard the progression of ONFH, and surgical procedures including joint preservation procedures and hip arthroplasties are main treatments for the disease. Although ONFH is the most common or second most common disease for hip arthroplasty in East Asian countries, the trend of surgical procedures in this region remains unknown. Thus, we evaluated trends in surgical treatment of the disease in South Korea. Methods: We identified patients with ONFH from the Korean Health Insurance Review and Assessment (HIRA) database, a nationwide medical claims database of South Korea, between January 2007 and December 2018 and calculated the proportions of following surgical procedures at each year: total hip arthroplasty (THA), hemiarthroplasty (HA), core decompression/multiple drilling, femoral osteotomy, and vascularized bone grafting. Results: The total number of procedures increased from 3,824 in 2007 to 6,929 in 2018. Overall, the rate of THA (86%) was far greater than other procedures. From 2007 to 2018, the percentage of THA among the procedures increased from 80% to 91%, while that of joint preservation procedures decreased from 11% to 5%. Conclusions The total number of surgical procedures performed for ONFH increased and the percentage of THA increased, while that of joint preservation procedures decreased from 2007 to 2018 in South Korea.

Objective: This study aimed to evaluate the superimposition accuracy of digital modes for measuring tooth movement in patients requiring anterior retraction after premolar extraction based on the proposed reference regions. Methods: Forty patients treated with bilateral maxillary first premolar extraction were divided into two groups: moderate retraction (< 7.0 mm) and maximum retraction (≥ 7.0 mm). Central incisor displacement was measured using cephalometric superimpositions and three-dimensional (3D) digital superimpositions with the 3rd or 4th ruga as the reference point. The Wilcoxon signed-rank test and linear regression analyses were performed to test the significance of the differences and relationships between the two measurement techniques. Results: In the moderate retraction group, the central incisor anteroposterior displacement values did not differ significantly between 3D digital and cephalometric superimpositions. However, in the maximum-retraction group, significant differences were observed between the anteroposterior displacement evaluated by the 3rd ruga superimposition and cephalometric methods (p < 0.05). Conclusions This study demonstrated that 3D digital superimpositions were clinically as reliable as cephalometric superimpositions in assessing tooth movements in patients requiring moderate retraction. However, the reference point should be carefully examined in patients who require maximum retraction.

For safe thyroidectomy, preservation of the parathyroid gland is mandatory. However, until recently, there has been no reliable method of identifying the parathyroid glands. Thus, the identification of the parathyroid gland has mainly depended on the surgeon’s personal experience. To overcome this limitation, near infrared autofluorescence (NIRAF) imaging technique has been introduced. Many reports support the claim that NIRAF imaging can help surgeons identify the parathyroid gland. However, there have been no reports on the feasibility of NIRAF imaging in detecting the intrathyroidal parathyroid glands that cannot be seen by the naked eye. Recently, we experienced two cases in which intrathyroidal parathyroid glands were identified and auto-transplanted with the use of NIRAF. We would like to share this experience and hope this paper helps thyroid surgeons identify the parathyroid gland more easily which is always a matter of concern.

Background/Aims: Real-world, clinical practice data are lacking about sofosbuvir/ ribavirin (SOF/RBV) treatment of Korean patients with hepatitis C virus genotype 2 (HCV GT2) infection. This study investigated the efficacy and safety of SOF/RBV in Korean patients with HCV GT2 infection and clinical factors predicting sustained virological response 12 weeks (SVR12) after the end of SOF/RBV treatment. Methods: A total of 181 patients with HCV GT2 with/without cirrhosis were treated with SOF/RBV for 16/12 weeks. Rapid virological response (RVR) was defined as non-detectable HCV RNA at 4 weeks. Results: The RVR rate was 80.7% (146/181), the end of treatment response rate was 97.8% (177/181) and the SVR12 rate was 92.8% (168/181). Of eight patients with relapse, four did not achieve RVR. Three patients had a history of hepatocellular carcinoma (HCC). Multivariable analysis showed that RVR (p = 0.015) and no previous history of HCC (p = 0.007) were associated with SVR12. Factors significantly contributing to RVR included cirrhosis, creatinine concentration, and pre-treatment HCV RNA level. SVR12 rate was significantly higher in RVR (+) than RVR (–) patients (95.2% vs. 82.9%, p = 0.011) and also significantly higher in patients without than with a history of HCC (94.1% vs. 72.7%, p = 0.008). During treatment, 80/181 patients (44.2%) experienced mild to moderate adverse events, with 32 (17.7%) requiring RBV dose reductions due to anemia. Conclusions SOF/RBV treatment was effective and tolerable in HCV GT2 patients. RVR and no previous history of HCC were positive predictors of SVR12.

Background/Aims: Real-world, clinical practice data are lacking about sofosbuvir/ ribavirin (SOF/RBV) treatment of Korean patients with hepatitis C virus genotype 2 (HCV GT2) infection. This study investigated the efficacy and safety of SOF/RBV in Korean patients with HCV GT2 infection and clinical factors predicting sustained virological response 12 weeks (SVR12) after the end of SOF/RBV treatment. Methods: A total of 181 patients with HCV GT2 with/without cirrhosis were treated with SOF/RBV for 16/12 weeks. Rapid virological response (RVR) was defined as non-detectable HCV RNA at 4 weeks. Results: The RVR rate was 80.7% (146/181), the end of treatment response rate was 97.8% (177/181) and the SVR12 rate was 92.8% (168/181). Of eight patients with relapse, four did not achieve RVR. Three patients had a history of hepatocellular carcinoma (HCC). Multivariable analysis showed that RVR (p = 0.015) and no previous history of HCC (p = 0.007) were associated with SVR12. Factors significantly contributing to RVR included cirrhosis, creatinine concentration, and pre-treatment HCV RNA level. SVR12 rate was significantly higher in RVR (+) than RVR (–) patients (95.2% vs. 82.9%, p = 0.011) and also significantly higher in patients without than with a history of HCC (94.1% vs. 72.7%, p = 0.008). During treatment, 80/181 patients (44.2%) experienced mild to moderate adverse events, with 32 (17.7%) requiring RBV dose reductions due to anemia. Conclusions SOF/RBV treatment was effective and tolerable in HCV GT2 patients. RVR and no previous history of HCC were positive predictors of SVR12.

For safe thyroidectomy, preservation of the parathyroid gland is mandatory. However, until recently, there has been no reliable method of identifying the parathyroid glands. Thus, the identification of the parathyroid gland has mainly depended on the surgeon’s personal experience. To overcome this limitation, near infrared autofluorescence (NIRAF) imaging technique has been introduced. Many reports support the claim that NIRAF imaging can help surgeons identify the parathyroid gland. However, there have been no reports on the feasibility of NIRAF imaging in detecting the intrathyroidal parathyroid glands that cannot be seen by the naked eye. Recently, we experienced two cases in which intrathyroidal parathyroid glands were identified and auto-transplanted with the use of NIRAF. We would like to share this experience and hope this paper helps thyroid surgeons identify the parathyroid gland more easily which is always a matter of concern.