Background: s/Aims: Reported incidence of extrahepatic bile duct cancer is higher in Asians than in Western populations. Korea, in particular, is one of the countries with the highest incidence rates of extrahepatic bile duct cancer in the world. Although research and innovative therapeutic modalities for extrahepatic bile duct cancer are emerging, clinical guidelines are currently unavailable in Korea. The Korean Society of Hepato-Biliary-Pancreatic Surgery in collaboration with related societies (Korean Pancreatic and Biliary Surgery Society, Korean Society of Abdominal Radiology, Korean Society of Medical Oncology, Korean Society of Radiation Oncology, Korean Society of Pathologists, and Korean Society of Nuclear Medicine) decided to establish clinical guideline for extrahepatic bile duct cancer in June 2021. Methods: Contents of the guidelines were developed through subgroup meetings for each key question and a preliminary draft was finalized through a Clinical Guidelines Committee workshop. Results: In November 2021, the finalized draft was presented for public scrutiny during a formal hearing. Conclusions The extrahepatic guideline committee believed that this guideline could be helpful in the treatment of patients.

Purpose: The purpose of this study was to investigate the effects of posterior oblique sling activation on the muscle activities of the gluteus maximus (GM), multifidus (MF), and biceps femoris (BF) during three different prone hip extension exercises in healthy male individuals. Methods: Twenty healthy subjects participated in this study. An electromyography device was used to measure the muscle activities of the GM, MF, and BF. Each subject was asked to perform three different prone hip extensions as follows: [1) Prone hip extension with knee flexion + hip abduction 30°; PHE1, 2) Prone hip extension with knee flexion + hip abduction 30° and shoulder abduction 125°; PHE2, 3) Prone hip extension with knee flexion + hip abduction 30° and shoulder abduction 125° with 1kg loading; PHE3, in random order. A oneway repeated measures analysis of the variance and a Bonferroni post hoc test were used to analyze the results. The statistical signifi-cance was set at α= 0.01. Results: The muscle activity of the GM was significantly different between the three positions (Padj < 0.01). The muscle activity of the GM was significantly greater during PHE3 compared with PHE1 and PHE2 (Padj < 0.01). The BF muscle activity was significantly lower during PHE3 compared with PHE1 and PHE2 (Padj < 0.01). There was no significant difference in the muscle activity of the MF (Padj < 0.01). The ratio of the muscle activity (ratio= GM/BF) during PHE3 was significantly greater compared to PHE1 and PHE2 (Padj < 0.01). Conclusion The GM activity and GM/BF ratio during the PHE3 exercise were significantly greater compared to that during PHE1 and PHE2. Therefore, the PHE3 exercise could be recommended as a selectively effective GM activation exercise while decreasing the muscle activity of the BF.

Purpose: Ankle dorsiflexion is an essential element of normal functions, including walking, activities of daily living and sport activities.The tibialis anterior (TA) muscle functioned as a dorsiflexor and as a dynamic stabilizer of the ankle joint during walking and jumping.This study aimed to compare TA muscle thickness using ultrasonography according to the four different toe and ankle postures for the selective TA strengthening exercise. Methods: This study were recruited 26 (males: 15, females: 11) aged 20-30 years, with no injury ankle and calf in the medical history, had normal dorsiflexion and inversion range of motion (ROM). The thickness of the TA muscle was measured by ultrasonography in the four different toe and ankle postures: 1. Ankle dorsiflexion with all toe extension and ankle inversion (ITEDF); 2. Ankle dorsiflexion with all toe flexion and ankle inversion (ITFDF); 3. Ankle dorsiflexion with all toe extension and neutral position (NTEDF); 4. Ankle dorsiflexion with all toe flexion and neutral position (NTFDF). One-way repeated analysis of variance (ANOVA) and Bonferroni correction were used to confirm the significant difference among conditions. The level of statistical significance was set at α = 0.01. Results: TA muscle thickness with ITFDF was significantly greater than in any other ankle positions, including ITEDF, NTFDF, and NTEDF (p < 0.01). Conclusion Among the four toe and ankle postures, isometric contraction in ITFDF postures showed the greatest increase in thickness of TA rather than ITEDF, NTEDF, and NTFDF postures. Based on these results, ITFDF can be recommended in an efficient way to selectively strengthen TA muscle.

Purpose: This study investigated the muscle activity of the lower trapezius (LT) during three different shoulder flexion exercises. Methods: Twenty-three subjects between 20 and 25 years of age were enrolled. The subjects were asked to perform three different shoulder flexion exercises: 1) shoulder flexion in prone (SFP), 2) shoulder flexion in push-up with a swiss ball (SFPUS) and 3) shoulder flexion in a quadruped position with a swiss ball (SFQPS) in random order. The muscle activity of LT during each shoulder flexion exercise was measured by using surface electromyography. The muscle activity of LT was compared using one-way analysis of variance (ANOVA) and Bonferroni post hoc test among three different shoulder flexion exercises. The statistical significance level was set at α = 0.01. Results: The muscle activity of LT was significantly different among three different shoulder flexion exercises (SFP, SFPUS, and SFQPS).The LT muscle activity with SFQPS exercise was greater than SFP and SFPUS exercises (p < 0.01). There was no significant difference in LT muscle activity between SFP and SFPUS exercises (p > 0.01). Conclusion The LT muscle activity was greater during SFQPS than SFP and SFPUS. Therefore, SFQPS exercise can be recommended for selectively activation of LT muscle.

Purpose: When splitting a liver for adult and pediatric graft recipients, the retained left medial section (S4) will undergo ischemic necrosis and the right trisection graft becomes an extended right liver (ERL) graft. We investigated the fates of the retained S4 and its prognostic impact in adult split liver transplantation (SLT) using an ERL graft. Methods: This was a retrospective analysis of 25 adult SLT recipients who received split ERL grafts. Results: The mean model for end-stage liver disease (MELD) score was 27.3 ± 10.9 and graft-recipient weight ratio (GRWR) was 1.98 ± 0.44. The mean donor age was 26.5 ± 7.7 years. The split ERL graft weight was 1,181.5 ± 252.8 g, which resulted in a mean GRWR of 1.98 ± 0.44. Computed tomography of the retained S4 parenchyma revealed small ischemic necrosis in 16 patients (64.0%) and large ischemic necrosis in the remaining 9 patients (36.0%). No S4-associated biliary complications were developed. The mean GRWR was 1.87 ± 0.43 in the 9 patients with large ischemic necrosis and 2.10 ± 0.44 in the 15 cases with small ischemic necrosis (P = 0.283). The retained S4 parenchyma showed gradual atrophy on follow-up imaging studies. The amount of S4 ischemic necrosis was not associated with graft (P = 0.592) or patient (P = 0.243) survival. A MELD score of >30 and pretransplant ventilator support were associated with inferior outcomes. Conclusion The amount of S4 ischemic necrosis is not a prognostic factor in adult SLT recipients, probably due to a sufficiently large GRWR.

Purpose: The purpose of the current study was to determine the intra- and inter-rater reliability of muscle thickness measurement of the TA using ultrasonography (US) conducted at different inward pressures of approximately 0.5 kg, 1.0 kg, and no pressure control. Methods: Twenty healthy subjects were recruited for this study. Two different examiners measured the thicknesses of the dominant TA of each subject randomly to assess the intra- and inter-rater reliability. The measurement values were analyzed using the intra-class correlation coefficient (ICC) with a 95% confidence interval, standard error of measurement, minimal detectable change, and coefficient of variance. Results: All intra-rater reliability ICC values showed high reliability above 0.9. Inter-rater reliability ICC values showed high reliability above 0.9 with 0.5 and 1.0 kg of inward pressure. In contrast, Inter-rater reliability ICC values showed poor reliability (0.23) with no pressure control of inward pressure. Conclusion The findings showed that maintaining consistent inward pressure is essential for reliable results when the muscle thickness of the TA is measured by different examiners in a clinical setting.

Purpose: Epithelioid hemangioendothelioma (EHE) is a rare borderline vascular tumor. This retrospective, single-center study evaluated the outcomes of hepatic resection (HR) in patients with hepatic EHE. Methods: Over the 10-year period from 2009 to 2018, 11 patients with hepatic EHE underwent HR, accounting for 0.1% of the 11,979 adults who underwent HR at our center. Diagnosis of hepatic EHE was confirmed by immunohistochemical staining for CD34, CD31, and factor VIII-related antigen. Results: The 11 patients included 9 females (81.8%) and 2 males (18.2%) with mean age of 43.5 ± 13.6 years. Preoperative imaging resulted in a preliminary diagnosis of suspected liver metastasis or EHE, with 9 patients (81.8%) undergoing liver biopsy. No patient presented with abnormally elevated concentrations of liver tumor markers. The extents of HR were determined by tumor size and location from trisectionectomy to partial hepatectomy. All patients recovered uneventfully from HR. Five patients showed tumor recurrence, with 4 receiving locoregional treatments for recurrent lesions. The 1-, 3-and 5-year disease-free survival rates were 90.9%, 54.5%, and 54.5%, respectively. Currently, all patients remain alive and are doing well. Univariate analysis on tumor recurrence showed that tumor size ≥ 4 cm was significantly associated with tumor recurrence (P = 0.032), but tumor number ≥ 4 was not related to (P = 0.24). Conclusion Hepatic EHE is a rare form of primary liver tumor often misdiagnosed as a metastatic tumor. Because of its malignant potential, HR is indicated if possible. HR plus, when necessary, treatment of recurrence yields favorable overall survival rates in patients with hepatic EHE.

Purpose: When splitting a liver for adult and pediatric graft recipients, the retained left medial section (S4) will undergo ischemic necrosis and the right trisection graft becomes an extended right liver (ERL) graft. We investigated the fates of the retained S4 and its prognostic impact in adult split liver transplantation (SLT) using an ERL graft. Methods: This was a retrospective analysis of 25 adult SLT recipients who received split ERL grafts. Results: The mean model for end-stage liver disease (MELD) score was 27.3 ± 10.9 and graft-recipient weight ratio (GRWR) was 1.98 ± 0.44. The mean donor age was 26.5 ± 7.7 years. The split ERL graft weight was 1,181.5 ± 252.8 g, which resulted in a mean GRWR of 1.98 ± 0.44. Computed tomography of the retained S4 parenchyma revealed small ischemic necrosis in 16 patients (64.0%) and large ischemic necrosis in the remaining 9 patients (36.0%). No S4-associated biliary complications were developed. The mean GRWR was 1.87 ± 0.43 in the 9 patients with large ischemic necrosis and 2.10 ± 0.44 in the 15 cases with small ischemic necrosis (P = 0.283). The retained S4 parenchyma showed gradual atrophy on follow-up imaging studies. The amount of S4 ischemic necrosis was not associated with graft (P = 0.592) or patient (P = 0.243) survival. A MELD score of >30 and pretransplant ventilator support were associated with inferior outcomes. Conclusion The amount of S4 ischemic necrosis is not a prognostic factor in adult SLT recipients, probably due to a sufficiently large GRWR.

Purpose: The purpose of the current study was to determine the intra- and inter-rater reliability of muscle thickness measurement of the TA using ultrasonography (US) conducted at different inward pressures of approximately 0.5 kg, 1.0 kg, and no pressure control. Methods: Twenty healthy subjects were recruited for this study. Two different examiners measured the thicknesses of the dominant TA of each subject randomly to assess the intra- and inter-rater reliability. The measurement values were analyzed using the intra-class correlation coefficient (ICC) with a 95% confidence interval, standard error of measurement, minimal detectable change, and coefficient of variance. Results: All intra-rater reliability ICC values showed high reliability above 0.9. Inter-rater reliability ICC values showed high reliability above 0.9 with 0.5 and 1.0 kg of inward pressure. In contrast, Inter-rater reliability ICC values showed poor reliability (0.23) with no pressure control of inward pressure. Conclusion The findings showed that maintaining consistent inward pressure is essential for reliable results when the muscle thickness of the TA is measured by different examiners in a clinical setting.

Purpose: The purpose of this study was to compare the influence of external scapular stabilization on the isometric strength of shoulder flexor muscle in subjects with and without scapular winging and conditions with and without external scapular stabilization. Methods: A total of 30 subjects with and without scapular winging were enrolled. Two groups were classified using clinical and diagnostic tests to divide the groups with and without scapular winging (15 with scapular winging 15 without scapular winging). The isometric strength of the shoulder flexor was measured using a tensiometer. The isometric strength was evaluated in the sitting position with and without an external scapular stabilization. The external scapular stabilization was provided with the examiner’s hand to fix scapular winging during shoulder flexion. The changing value was calculated to determine the isometric strength difference between shoulder flexion with and without the external scapular stabilization in each group. The changing value between isometric strength of shoulder flexor with and without scapular winging was compared using the independent t-test. Statistical significance was set at 0.05. Results: In the group with scapular winging, the shoulder flexor isometric strength in the sitting position was greater with an external scapular stabilization than without an external scapular stabilization (p < 0.05). There was no significant difference in the shoulder flexor isometric strength in the subjects without scapular winging between conditions with or without an external scapular stabilization (p > 0.05). Conclusion The external scapular stabilization in the individuals with scapular winging may increase shoulder flexor isometric strength in the sitting position.