Impact of Glissonean Pedicle Approach for Centrally Located Hepatocellular Carcinoma in Mongolia

Approaches to surgical resection of centrally located HCC remain controversial. Traditionally, hemi- or extended hepatectomy is suggested. However, it carries a high risk of postoperative complications in patients with cirrhosis. An alternative approach is Glissonean pedicle transection method. This study was conducted to assess the surgical and survival outcomes associated with central liver resection using the Glissonean pedicle transection. Sixty-nine patients with centrally located HCC were studied retrospectively. They were divided into conventional approach group with hemi- or extended hepatectomy, and Glissonean approach group with multisegmental central liver resection using the Glissonean pedicle transection. Glissonean pedicle transection method has comparable or superior surgical and survival outcomes to conventional hemi- or extended hepatectomy with regard to intraoperative bleeding, complications, hospital stay, and postoperative mortality and survival outcomes in patients with centrally located HCC. The 1-, 3-, and 5-year overall survival rates of the conventional approach group were 74%, 64%, and 55% respectively. For the Glissonean approach group, the 1 and 3-year overall survival rates were 86% and 61%, respectively. Glissonean pedicle transection method is a safe and effective surgical procedure in patients with centrally located HCC.Key words: Centrally located HCC, Glissonean approach, Glissonean pedicle transection, Central hepatectomyHepatocellular carcinoma (HCC) is the first leading cause of cancer-related mortality in both men and women in Mongolia, and its incidence is among the highest worldwide.¹ Surgical resection remains the first-line therapeutic strategy for HCC despite recent advancements in treatment modalities.^2-4 However, underlying liver diseases significantly limit the number of HCC patients eligible for surgical resection. This is especially problematic, where the prevalence of chronic hepatitis B and C is over 10% in the general population, and 86.8% of HCC patients have cirrhosis.⁵ Therefore, refining surgical techniques to preserve as much liver parenchyma as possible could potentially improve treatment prospects for cirrhotic HCC patients, particularly in cases when the tumor is centrally located.Traditionally, hemi- or extended hepatectomy is suggested for the treatment of centrally located HCC.⁶ However, such a major hepatic resection sacrifices a large volume of noncancerous liver parenchyma, which carries a high risk of postoperative liver failure in patients with cirrhotic background.^6-8 Preservation of functioning liver parenchyma to a maximum extent possible is crucial to avoid postoperative liver failure in cirrhotic patients. Therefore, Glissonean pedicle transection method is increasingly considered as an effective alternative to hemi- or extended hepatectomies in such cases.^9-16 Nonetheless, multisegmental central liver resection has not been widely used since its introduction for gallbladder cancer in 1972.^17,18 Conventional central liver resection method is technically demanding, and may require prolonged surgical time in order to dissect and confirm each branch of hepatic artery, portal vein, and bile duct to the anterior section.^19,20 This often results in increased risk of bleeding, bile leakage or parenchymal necrosis, and therefore, central liver resection particularly in cirrhotic patients remains controversial.^21,22 The answer to the dilemma could lie with the Glissonean pedicle transection method, which was introduced in the mid-1980s owing to a better understanding of the surgical anatomy of the liver.^20,23 When using this resection method, Glissonean pedicle supplying the target area is ligated and divided at the hepatic hilum prior to resection without exposing the vessels individually.²³ This simplifies hepatic resection, shortens operation time and reduces intraoperative bleeding.²³⁻²⁵ Our previous experience with using this method for hemihepatectomy has resulted in considerable reduction of blood loss during resection, a major determinant of patient outcome.This approach has allowed the ability to adapt the size of resection to the extent of the tumor and to preserve the maximum amount of liver parenchyma, which is crucial for the prevention of postoperative liver failure especially in patients with cirrhotic background. However, it remains unclear whether central liver resection using the Glissonean pedicle transection improves long-term survival. Therefore, the current retrospective study of patients with centrally located HCC, who underwent either hemi- or extended hepatectomy or multisegmental central liver resection, was conducted to assess the perioperative and long-term outcomes associated with central liver resection using the Glissonean pedicle transection.     

Cognitive Analysis of Educational Games: The Number Game

We analyze the cognitive strategies underlying performance in the Number task, a Math game that requires both arithmetic fluency and mathematical creativity. In this game all elements in a set of numbers (for instance, 2, 5, 9) have to be used precisely once to create a target number (for instance, 27) with basic arithmetic operations (solution: [5−2] × 9). We argue that some instances of this game are NP complete, by showing its relation to the well-known Partition problem. We propose heuristics based on the distinction in forward and backward reasoning. The Number Game is part of Math Garden, a popular online educational platform for practicing and monitoring math skills using innovations in computerized adaptive testing. These educational games generate enormous amounts of rich data on children's cognitive development. We found converging evidence for the use of forward proximity heuristics in the data of Math Garden, consisting of more than 20 million answers to 1,700 items. Item difficulties and the structure of correct answers were analyzed.     

Genetic and antigenic characterization of H5 and H7 avian influenza viruses isolated from migratory waterfowl in Mongolia from 2017 to 2019

Virus Genes - The circulation of highly pathogenic avian influenza viruses (HPAIVs) of various subtypes (e.g., H5N1, H5N6, H5N8, and H7N9) in poultry remains a global concern for animal and public...     

HIV/AIDS related knowledge and risk behaviors among female sex workers in two major cities of Mongolia

The prevalence of HIV/AIDS in Mongolia is still low. Only 29 HIV/AIDS cases have been registered in Mongolia with a population of 2.6 millions, as of April, 2007. In all of the cases the infection has been sexually transmitted and almost 90.0% of total HIV/AIDS cases have been detected since 2005. Past studies conducted in Mongolia indicated that sexually transmitted infections (STIs) had been spreading rapidly among high risk groups, which highlights an urgent need for prevention mainly targeting these groups. This study was conducted to evaluate HIV/AIDS related knowledge/behaviors, as well as to assess the prevalence of HIV and syphilis among female sex workers (SWs) in two major cities of Mongolia. A total of 342 sex workers (199 females from Darkhan and 143 females from Ulaanbaatar city) with the mean age of 25.8 years participated in the study. In Darkhan, HIV/AIDS related knowledge of SWs was higher (99.0%) and the prevalence of syphilis was lower (3.5%) than in Ulaanbaatar (88.8% and 36.0%, respectively). No new HIV cases among the female SWs have been detected despite high syphilis rates (17.4%) among the study subjects. Although condom useat last sex with paying clients was high (92.3%), the rate was low with non-paying, non-regular sex partners (56.9%). These findings indicated that despite relatively good HIV/AIDS related knowledge, high risk sexual behaviors were still common among the female SWs.     

Genetic and virulence characterization of classical swine fever viruses isolated in Mongolia from 2007 to 2015

Classical swine fever (CSF), a highly contagious viral disease affecting domestic and wild pigs in many developing countries, is now considered endemic in Mongolia, with 14 recent outbreaks in 2007, 2008, 2011, 2012, 2014, and 2015. For the first time, CSF viruses isolated from these 14 outbreaks were analyzed to assess their molecular epidemiology and pathogenicity in pigs. Based on the nucleotide sequences of their 5′-untranslated region, isolates were phylogenetically classified as either sub-genotypes 2.1b or 2.2, and the 2014 and 2015 isolates, which were classified as 2.1b, were closely related to isolates from China and Korea. In addition, at least three different viruses classified as 2.1b circulated in Mongolia. Experimental infection of the representative isolate in 2014 demonstrated moderate pathogenicity in 4-week-old pigs, with relatively mild clinical signs. Understanding the diversity of circulating CSF viruses gleans insight into disease dynamics and evolution, and may inform the design of effective CSF control strategies in Mongolia.