Background/Aims: We investigated whether patients with inflammatory bowel disease (IBD) in Korea have an increased risk of hepatitis A virus (HAV) and hepatitis C virus (HCV) infections and sought to identify the risk factors for these infections. Methods: We performed a nationwide population-based study using 2013–2021 data from the Korean National Health Insurance Claims Database. We calculated the incidence rates and standardized incidence ratios (SIRs) of HAV and HCV infections in patients with IBD compared with the overall Korean population. Results: A total of 43,513 patients were included in this study. A total of 317 cases of HAV were identified in 276,007 perdison- years, while 297 cases of HAV developed in the Korean general population. The SIR of HAV in the patients with IBD was 1.07 (95% confidence interval [CI], 0.96–1.19) and the increase of HAV infection in patients with IBD was not statistically significant. A total of 289 cases of HCV infection were identified in 276,538 person-years, while 242 cases of HCV infection developed in the Korean general population. The SIR of HCV in patients with IBD was 1.19 (95% CI, 1.06–1.34) and the increase of HCV infection in patients with Crohn's disease (SIR, 1.63; 95% CI, 1.31–2.04). Corticosteroid use was identified as a risk factor for HAV and HCV infections in patients with IBD. Conclusions HCV showed an increasing trend in Korean patients with IBD, especially those with Crohn's disease. Corticosteroids use is a risk factor for hepatitis in patients with IBD.

Background: s/Aims: Phase angle (PhA), as measured by bioelectrical impedance analysis, provides insights into hydration and nutritional status, making it a prognostic indicator of frailty. While low preoperative PhA has been linked to postoperative complications in cancer patients, its predictive value in individuals undergoing pancreaticoduodenectomy (PD) has not been thoroughly investigated.This study aims to evaluate the clinical utility of preoperative PhA in predicting postoperative complications for patients undergoing PD. Methods: Among 41 patients who underwent PD at Seoul National University Hospital between September and December 2024, 35 were included in the analysis after excluding 6 patients who had concomitant blood vessel or other organ resections. Patients were divided into low (Comprehensive Complication Index [CCI] ≤ 20) and high (CCI > 20) complication groups based on the CCI, derived from the Clavien–Dindo classification. The differences in PhA between the two groups were analyzed, and logistic regression was performed to assess the relationship between PhA and CCI. Results: The mean PhA was significantly lower in the high-CCI group compared to the low-CCI group (5.7° vs. 6.7°, p = 0.025). Multivariate logistic regression analysis indicated that PhA (odds ratio: 0.17; 95% confidence interval: 0.04–0.68; p = 0.012) was an independent predictor of high CCI. A low preoperative PhA was associated with an increased risk of postoperative complications following PD. Conclusions Preoperative PhA may serve as a valuable predictive indicator of postoperative complications after PD, enabling the identification of patients who could benefit from preoperative prehabilitation, including nutritional support.

Purpose: This study evaluated the causes and risk factors for revision surgery after anterior cervical discectomy and fusion (ACDF) for lower cervical degenerative diseases and verified the factors that can reduce the possibility of revision surgery. Materials and Methods: Six hundred and sixty-one patients who underwent ACDF by one of two board-certified orthopedic spine surgeons for lower cervical degenerative diseases between 2004 and 2021 were enrolled in this study. The patients were divided into two groups based on whether or not they had undergone revision surgery. The statistical significance was analyzed for the age, sex, height, weight, body mass index, status of diabetes mellitus, symptoms at presentation (radiculopathy, myelopathy, and myelo-radiculopathy), number of fusion level, graft type, and smoking status of patients in each group to assess the risk factors for revision surgery. For statistical analysis, a Fisher’s exact test, t-test, and chi-square analysis were conducted according to variables. Results: Fifty-two out of 661 (7.9%) patients underwent revision surgery. The revision surgery took place at an average of 66.3 months after ACDF. The reason for revision surgery was adjacent segment disease (ASD) in 28 (53.8%), pseudoarthrosis in 10 (19.2%), hardwarerelated problems in 4 (7.7%), both ASD and pseudoarthrosis in 3 (5.8%), infection in 3 (5.8%) and other segmental disease in 4 (7.7%) of those patients. The need for revision surgery was unaffected by age, sex, height, weight, body mass index, status of diabetes mellitus, symptoms at presentation, and graft type (p>0.05). The statistical significance of revision surgery was confirmed in patients with multisegment fusion level (≥3 levels, p=0.048) and smoking patients (p<0.001). Conclusion Multi-segment fusion should be avoided, and smoking should be ceased during the perioperative period to reduce the risk of revision surgery when considering ACDF for degenerative cervical spine diseases.

Background: Thrombocytopenia is a condition where platelet counts are below the normal range (< 150 ×103 /µL), resulting in a higher risk of bleeding and affecting the results of hip arthroplasty. We assessed the impact of preoperative platelet counts on the clinical results of patients who underwent hip arthroplasty. Methods: Between April 2003 and March 2023, 437 patients (451 hips), who had preoperative thrombocytopenia of less than 150 ×103 /µL platelets, underwent hip arthroplasty. Preoperative platelet levels were categorized into severe thrombocytopenia (< 50 ×103 /µL) and non-severe thrombocytopenia (50–149 ×103 /µL). Total blood loss, operation time, requirement of transfusion, amount of transfusion, duration of surgical wound oozing, length of hospital stay, mortality rate at 1 year after surgery, and any complication were compared between the 2 groups. Results: No notable differences were observed in the surgery time or the total amount of blood loss between the groups. The requirement of transfusion and the amount of transfused blood were higher in the severe thrombocytopenia group. Prolonged oozing was found in around 18% in both groups, while periprosthetic joint infections occurred in 3 of the non-severe thrombocytopenia group. No significant difference was noted in the duration of hospital stay (25.6 ± 18.3 days vs. 19.4 ± 16.6 days, p = 0.067) and 1-year mortality (22.2% vs. 11.8%, p = 0.110). Conclusions Hip arthroplasties are safe for patients with low platelet counts and do not lead to prolonged hospital stays. On the other hand, patients with severe thrombocytopenia tend to need blood transfusions more frequently than those with less severe thrombocytopenia.

Background: The Arbeitsgemeinschaft für Osteosynthesefragen (AO) and the Orthopaedic Trauma Association (OTA) classification system for diaphyseal fracture has been recently revised to refine and enhance the accuracy of fracture categorization. This study aimed to investigate the interobserver reliability of the new AO/OTA classification and to compare it with the older version in femoral shaft fractures. Methods: We retrospectively analyzed 139 patients (mean age, 43.8 ± 19.5 years; 92 men and 47 women) with femoral shaft fractures who were treated from 2003 to 2017. Four well-trained observers independently classified each fracture following the previous and revised AO/OTA classification system. We calculated the Fleiss kappa for the interobserver reliability. Results: The previous classification showed the kappa value of 0.580 (95% confidence interval [CI], 0.547–0.613), and the revised version showed 0.528 (95% CI, 0.504–0.552). Both the old and the revised versions showed moderate reliability. Conclusions Our study highlights the moderate interobserver reliability of both the previous and new AO/OTA classification systems for diaphyseal femur fractures. These findings emphasize the importance of standardized systems in clinical decision-making and underscore the need for ongoing education and collaboration to enhance fracture classification.

Purpose: Prognostic Index for Natural Killer Lymphoma (PINK) is the most widely accepted prognostic model for patients withextranodal natural killer/T-cell lymphoma (ENKTL) treated with non-anthracycline–based therapy. We aimed to evaluate the prognostic implications of serum β-2 microglobulin (β2M) in the context of PINK and proposed a new prognostic model. Materials and Methods: A total of 138 patients who were newly diagnosed with ENKTL and treated with non-anthracycline-based chemotherapy were identified. The cut-off value of high serum β2M was calculated by maximal-chi square methods (4.1 mg/L). A new prognostic model incorporating serum β2M into PINK was proposed and validated in an independent validation cohort (n=88). Results: The patients’ median age was 53.5 years (range, 19 to 80 years). Patients with high serum β2M levels had significantly worse overall survival (OS) and progression-free survival (PFS). In multivariate analysis, high serum β2M was an independent adverse prognostic factor for OS. A new PINK-B (Prognostic Index for Natural Killer Lymphoma-serum β-2 microglobulin) model stratifiedpatients into three groups with distinct OS and PFS in the training cohort (3-year OS, 84.1% [95% confidence interval, 75.1 to 94.2], 46.8% [36.1 to 60.8] and 17.6% [6.3 to 49.2] for the low-, intermediate, and high-risk groups, respectively; 3-year PFS, 70.6% [59.4 to 83.8], 35.9% [25.9 to 49.8], and 7.35% [1.1 to 46.7] for the low-, intermediate-, and high-risk groups, respectively). The PINK-B model was further validated in an independent cohort. Conclusion Serum β2M is an independent prognostic factor for ENKTL patients. The new serum β2M-based prognostic model may be useful for identifying ultra-high-risk patients, and it can easily be adopted into daily clinical practice.

Purpose: Tyrosine kinase inhibitors (TKI) targeting vascular endothelial growth factor receptor (VEGFR) signaling pathways have been used for metastatic clear cell renal cell carcinoma (mCCRCC), but resistance to the drug develops in most patients. We aimed to explore the underlying mechanism of the TKI resistance with regard to programmed death-ligand 1 (PD-L1) and to investigate signaling pathway associated with the resistant mechanism. Materials and Methods: To determine the mechanism of resistance, 10 mCCRCC patients from whom tumor tissues were harvested at both the pretreatment and the TKI-resistant post-treatment period were included as the discovery cohort, and their global gene expression profiles were compared. A TKI-resistant renal cancer cell line was established by long-term treatment with sunitinib. Results: Among differentially expressed genes in the discovery cohort, increased PD-L1 expression in post-treatment tissues was noted in four patients. Pathway analysis showed that PD-L1 expression was positively correlated with the mammalian target of rapamycin (mTOR) signaling pathway. The TKI-resistant renal cancer cells showed increased expression of PD-L1 and mTOR signaling proteins and demonstrated aggressive tumoral behaviour. Treatment with mTOR inhibitors down-regulated PD-L1 expression and suppressed aggressive tumoral behaviour, which was reversed with stimulation of the mTOR pathway. Conclusion These results showed that PD-L1 expression may be increased in a subset of VEGFR-TKI–resistant mCCRCC patients via the mTOR pathway.

According to recent evidence, ferroptosis is a major cell death mechanism in the pathogenesis of kidney injury and fibrosis.Despite the renoprotective effects of classical ferroptosis inhibitors, therapeutic approaches targeting kidney ferroptosis remain limited. In this study, we assessed the renoprotective effects of melatonin and zileuton as a novel therapeutic strategy against ferroptosis-mediated kidney injury and fibrosis. First, we identified RSL3-induced ferroptosis in renal tubular epithelial HK-2 and HKC-8 cells. Lipid peroxidation and cell death induced by RSL3 were synergistically mitigated by the combination of melatonin and zileuton. Combination treatment significantly downregulated the expression of ferroptosis-associated proteins, 4-HNE and HO-1, and upregulated the expression of GPX4. The expression levels of p-AKT and p-mTOR also increased, in addition to that of NRF2 in renal tubular epithelial cells. When melatonin (20 mg/kg) and zileuton (20 mg/kg) were administered to a unilateral ureteral obstruction (UUO) mouse model, the combination significantly reduced tubular injury and fibrosis by decreasing the expression of profibrotic markers, such as α-SMA and fibronectin. More importantly, the combination ameliorated the increase in 4-HNE levels and decreased GPX4 expression in UUO mice. Overall, the combination of melatonin and zileuton was found to effectively ameliorate ferroptosis-related kidney injury by upregulating the AKT/mTOR/ NRF2 signaling pathway, suggesting a promising therapeutic strategy for protection against ferroptosis-mediated kidney injury and fibrosis.

Background/Aims: While distal radial artery (DRA) access is increasingly being used for diagnostic coronary angiography, limited information is available regarding DRA size. We aimed to determine the DRA reference diameters of Korean patients and identify the predictors of DRA diameter < 2.3 mm. Methods: The outer bilateral DRA diameters were assessed using a linear ultrasound probe in 1,162 consecutive patients who underwent transthoracic echocardiography. The DRA diameter was measured by the perpendicular angle in the dorsum of the hand, and the average values were compared by sex. DRA diameter < 2.3 mm was defined as unsuitable for routine diagnostic coronary angiography using a 5 Fr introducer sheath. Results: The mean DRA diameters were 2.31 ± 0.43 mm (right) and 2.35 ± 0.45 mm (left). The DRA was smaller in women than men (right: 2.15 ± 0.38 mm vs. 2.43 ± 0.44 mm, p < 0.001; left: 2.18 ± 0.39 mm vs. 2.47 ± 0.45 mm, p < 0.001). The DRA diameter was approximately 20% smaller than the radial artery diameter. A total of 630 (54.2%) and 574 (49.4%) patients had DRA diameter < 2.3 mm in the right and left hands, respectively. Female sex, low body mass index (BMI), and low body surface area (BSA) were significant predictors of DRA diameter < 2.3 mm. Conclusions We provided reference DRA diameters for Korean patients. Approximately 50% of the studied patients had DRA diameter < 2.3 mm. Female sex, low BMI, and low BSA remained significant predictors of DRA diameter < 2.3 mm.

Background/Aims: Endoscopic submucosal dissection (ESD) is a curative treatment modality for early gastric neoplasms; however, ESD can be a time-consuming process. To overcome this pitfall, we developed the one-step knife (OSK) approach, which combines an endoscopic knife and injection needle on a single sheath. We aimed to evaluate whether this approach could reduce the ESD procedure time. Methods: This single-blinded randomized multicenter trial at four tertiary hospitals from June 2019 to June 2020 included patients aged 19 to 85 years undergoing ESD. Patients were randomly assigned to two groups (OSK or conventional knife [CK]). The injection time, total procedure time, resected specimen size, submucosal fluid amount, degree of device satisfaction, and adverse events were evaluated and compared between groups. Results: Fifty-one patients were analyzed (OSK: 25 patients and CK: 26 patients). No baseline differences were observed between groups, with the exception of a higher portion of males in the OSK group. The mean injection time was significantly reduced in the OSK group (39.0 seconds) compared to that in the CK group (87.5 seconds, p<0.001). A decrease of more than 10 minutes in the total procedure time (18.0 minutes vs 28.1 minutes, p=0.055) in the OSK group compared to the CK group was observed. Second-look esophagogastroduodenoscopy revealed two delayed bleeding cases in the OSK group that were easily controlled by endoscopic hemostasis. Conclusions OSK reduced the injection time and showed a decrease in total procedure time compared with the CK approach. OSK can be a feasible tool for ESD, especially in difficult cases.