Comparison Between Plastic and Metallic Biliary Stent Placement for Preoperative Patients with Pancreatic Head Cancer: A Systematic Review and Meta-Analysis.

BACKGROUND: Optimal preoperative biliary drainage for patients with pancreatic cancer before pancreatoduodenectomy remains unclear. This study aimed to investigate the comparison of efficacy and safety between a metallic stent (MS) and a plastic stent (PS). METHODS: Comparative studies on the use of MS and PS for pancreatic cancer before pancreatoduodenectomy were systematically searched using the MEDLINE and Web of Science databases. Pre- and postoperative data also were extracted. Random-effects meta-analyses were performed to compare post-endoscopic retrograde cholangiopancreatography (ERCP) complications as well as intra- and postoperative outcomes between the two arms of the study, and pooled odds ratios (ORs) or mean differences (MDs) were calculated with 95 percent confidence intervals (CIs). RESULTS: The study analyzed 12 studies involving 683 patients. Insertion of MS was associated with a lower incidence of re-intervention (OR, 0.06; 95% CI 0.03-0.15; P < 0.001), increased post-ERCP adverse events (OR, 2.22; 95% CI 1.13-4.36; P = 0.02), and similar operation time (MD, 18.0 min; 95% CI -29.1 to 65.6 min; P = 0.46), amount of blood loss (MD, 43.0 ml; 95% CI -207.1 to 288.2 ml; P = 0.73), and surgical complication rate (OR, 0.78; 95% CI 0.53-1.15; P = 0.21). The cumulative stent patency rate after 3 months was higher in the MS group than in the PS group (70-100 % vs 30.0-45.0 %). CONCLUSION: For biliary drainage in patients with pancreatic cancer during this era of multidisciplinary treatment, MS use might be the first choice because MS provides a more durable biliary drainage and a similar risk of postoperative outcomes compared with PS.

Preoperative predictive factors for positive peritoneal cytology results in patients with pancreatic ductal adenocarcinomas: a retrospective study.

BACKGROUND: The clinical importance of positive peritoneal cytology results in patients with pancreatic ductal adenocarcinomas remains controversial. We evaluated the prognosis of these patients and the predictive preoperative risk factors for positive peritoneal cytology results. METHODS: We retrospectively reviewed patients who underwent curative-intent surgery at our institution between May 2010 and June 2020. Preoperative risk factors for positive peritoneal cytology results were identified using logistic regression analysis. A scoring model was constructed using the total number of significant independent predictors for positive peritoneal cytology results. RESULTS: Of 233 patients, 18 (7.7%) had positive peritoneal cytology results. The recurrence-free survival and cancer-specific survival were markedly worse in patients with positive peritoneal cytology results than in those with negative peritoneal cytology results (recurrence-free survival: 6.0 months vs. 16.6 months, p = 0.050; cancer-specific survival: 19.4 months vs. 47.5 months, p = 0.034). Tumor location (odds ratio: 3.760, 95% confidence interval: 1.099-11.818, p = 0.023), tumor size > 25 mm (odds ratio: 3.410, 95% confidence interval: 1.031-11.277, p = 0.046), preoperative serosal invasion (odds ratio: 5.193, 95% confidence interval: 1.099-24.531, p = 0.038), and preoperative carcinoembryonic antigen level > 5.6 ng/mL (odds ratio: 3.816, 95% confidence interval: 1.248-10.667, p = 0.019) were identified as significant independent predictive factors. Our predictive model's optimal cutoff and positive predictive values for positive peritoneal cytology results were 3 and 27.9%, respectively. CONCLUSIONS: The indications for curative-intent surgery should be considered carefully in patients with high-risk factors for positive peritoneal cytology results.

Standardized upfront Glissonean approach and liver hanging maneuver reduces bile leakage from the hepatic hilum in living donors.

Biliary complications after hepatectomy in living donors have yet to be eradicated. We hypothesized that a standardized upfront Glissonean approach and liver hanging maneuver (GH) would prevent mechanical and thermal injuries to the hilar plate of the remnant liver by determining the point of bile duct division and the final destination of hepatectomy preceding liver parenchymal transection (safety) and facilitate liver transection deep within the parenchyma and allow maximum length of hilar structures (rationality). GH was implemented in 2016 and its incidence of bile leakage was retrospectively compared against the conventional technique. GH comprises six steps: (1) development of the retrohepatic avascular plane between the right hepatic vein (RHV) and the middle hepatic vein (MHV) and isolation of the hepatic vein(s); (2) isolation of the right or left Glissonean pedicle with the corresponding Glissonean pedicles of the caudate lobe; (3) for right liver grafts and left liver grafts with the caudate lobe, passage of the tape for the liver hanging maneuver along the retrohepatic avascular plane and above the hilar plate, and for left liver grafts without the caudate lobe and for left lateral section grafts, passage of the tape from between the RHV and the MHV, along the Arantius ligament, and to the right of the umbilical portion; (4) liver transection; (5) isolation of hilar structures; and (6) graft procurement. Until 2020, 62 consecutive living donors underwent GH (success rate, 100%). The incidence of bile leakage from the hepatic hilum (0%) was significantly lower than that among 59 donors who underwent the conventional technique in 2011-2015 (9%; p = 0.01). In conclusion, GH is highly effective in reducing bile leakage from the hepatic hilum in living donors.

Immunovascular classification of HCC reflects reciprocal interaction between immune and angiogenic tumor microenvironments.

BACKGROUND AND AIMS: Immune cells and tumor vessels constitute important elements in tumor tissue; however, their detailed relationship in human tumors, including HCC, is still largely unknown. Consequently, we expanded our previous study on the immune microenvironment of HCC and analyzed the relationship among the immune microenvironment, inflammatory/angiostatic factor expression, angiogenic factor expression, and tumor vessel findings, including vessels encapsulating tumor clusters (VETC) and macrotrabecular-massive (MTM) patterns. APPROACH AND RESULTS: We classified HCC into four distinct immunovascular subtypes (immune-high/angiostatic [IH/AS], immune-mid/angio-mid [IM/AM], immune-low/angiogenic [IL/AG], and immune-low/angio-low [IL/AL]). IH/AS, IM/AM, and IL/AG subtypes were associated with decreasing lymphocytic infiltration and increasing angiogenic factor expression and VETC/MTM positivity, reflecting their reciprocal interaction in the tumor microenvironment of HCC. IL/AG subtype was further characterized by CTNNB1 mutation and activation of Wnt/ß-catenin pathway. IL/AL subtype was not associated with increased lymphocyte infiltration or angiogenic factor expression. Prognostically, IH/AS subtype and VETC/MTM positivity were independently significant in two independent cohorts. Increased angiogenic factor expression was not necessarily associated with VETC/MTM positivity and poor prognosis, especially when inflammatory/angiostatic milieu coexisted around tumor vessels. These results may provide insights on the therapeutic effects of immunotherapy, antiangiogenic therapies, and their combinations. The potential of evaluating the immunovascular microenvironment in predicting the clinical effect of these therapies in nonresectable HCC needs to be analyzed in the future study. CONCLUSIONS: HCC can be classified into four distinct immunovascular subtypes (IH/AS, IM/AM, IL/AG, and IL/AL) that reflect the reciprocal interaction between the antitumor immune microenvironment and tumor angiogenesis. In addition to its clinicopathological significance, immunovascular classification may also provide pathological insights on the therapeutic effect of immunotherapy, antiangiogenic therapy, and their combination.

Risk Assessment of Liver Transplantation After Kasai Portoenterostomy in Children and Adults.

INTRODUCTION: Reports of liver transplantation (LT) after Kasai portoenterostomy (KPE) in adult patients with biliary atresia are scarce. The aim of this study was to evaluate the outcomes and investigate the risk factors of LT after KPE in both pediatric and adult patients. METHODS: We retrospectively reviewed a prospective database of patients with biliary atresia who underwent LT after KPE. Eighty-nine consecutive patients were included, and risk factors for in-hospital mortality after LT were assessed. RESULTS: The median age of the patients was 2 y (range, 0-45 y). Forty-six patients (51.7%) had a history of upper abdominal surgery after KPE. The in-hospital mortality rate was 5.6% (5 patients). Of these, 80% of patients with mortality were aged ≥17 y, and all patients with mortality had a history of two or more upper abdominal surgeries. In the univariate and receiver operating characteristic curve analyses, age ≥17 y and the number of previous upper abdominal surgeries ≥2 were identified as possible risk factors. CONCLUSIONS: Our study suggests that older age and multiple previous upper abdominal surgeries are important risk factors for mortality after LT following KPE. We believe that these findings will serve as indications for safe LT in future patients.

Immunovascular microenvironment in relation to prognostic heterogeneity of WNT/ß-catenin-activated hepatocellular carcinoma.

AIM: WNT/ß-catenin-activated hepatocellular carcinoma (W/B subclass HCC) is considered a molecularly homogeneous entity and has been linked to resistance to immunotherapy. However, recent studies have indicated possible heterogeneity in the immunovascular microenvironment in this subclass. We set out to test the hypothesis that specific immunovascular features might stratify W/B subclass HCCs into tumors having distinct aggressive natures. METHODS: In this study, we analyzed 352 resected HCCs including 78 immunohistochemically defined W/B subclass HCCs. The density of tumor-infiltrating CD3+ T cells and the area ratio of vessels encapsulating tumor clusters (VETC) were calculated on tissue specimens. The gene expressions of angiogenic factors were measured by quantitative reverse transcription-polymerase chain reaction. Disease-free survival (DFS) was assessed using multivariable Cox regression analyses. RESULTS: The T-cell density of W/B subclass HCCs was regionally heterogenous within tumor tissues, and focally reduced T-cell density was observed in areas with VETC. VETC-positivity (defined as VETC area ratio greater than 1%) was inversely associated with T-cell infiltration in both W/B subclass and non-W/B subclass HCCs. Fibroblast growth factor 2 (FGF2) gene expression was higher in W/B subclass than in non-W/B subclass HCCs. The VETC-positivity and low T-cell density correlated with increased expression of FGF2 in W/B subclass HCCs. Additionally, VETC-positive HCCs showed significantly shorter DFS in W/B subclass HCCs. CONCLUSIONS: In conclusion, the immune and vascular microenvironments are interrelated and are also correlated with clinicopathological heterogeneity in W/B subclass HCC. These results could inform clinical practice and translational research on the development of therapeutic stratification of HCCs.

Exposure of the hepatic vein trunk via tracing of its branches: a useful surgical procedure for laparoscopic anatomical hepatectomy.

BACKGROUND: Although there are various advantages of laparoscopic liver resection (LLR) over open liver resection, some problems have been reported, such as disorientation and lack of control of bleeding during liver parenchymal dissection. In this study, we discuss a strategy to overcome the disorientation experienced during liver parenchymal dissection, especially in anatomical LLR. TECHNICAL PRESENTATION: This procedure involves hepatic parenchymal dissection from the hepatic vein branch along its trunk to reveal an important landmark in anatomical LLR. Knowing which region of the liver is perfused into each hepatic vein in preoperative 3D simulation allows the tracing of the hepatic vein branch that naturally leads to the hepatic vein trunk. After that, hepatic resection can be easily completed by dissecting the line connected to the other landmarks, the Glisson branch, the root of the hepatic vein, and the liver demarcation line. CONCLUSION: In conclusion, this surgical procedure that traces the branch of the hepatic vein exposes the trunk, which makes it a very useful tool for limited laparoscopic anatomical hepatectomy.

Clinical characteristics and predictive factors of postoperative intra-abdominal abscess after distal pancreatectomy.

PURPOSE: The postoperative mortality rate of distal pancreatectomy is lower than that of pancreaticoduodenectomy, although persistent complications may occur after distal pancreatectomy. Fluid collection (FC) is frequently observed after distal pancreatectomy; however, FC may occasionally progress to postoperative intra-abdominal abscess (PIAA), which requires conservative or progressive interventional treatment. This study aimed to compare the status between patients with or without PIAA, identify predictive factors for PIAA and clinically relevant postoperative pancreatic fistula, and investigate the clinical characteristics of patients with PIAA with interventional drainage. METHODS: We retrospectively reviewed data of patients who underwent distal pancreatectomy between January 2012 and December 2019 at two high-volume centers, where hepatobiliary-pancreatic surgeries were performed by expert specialist surgeons. Logistic regression analysis was performed to determine the predictive factors for PIAA. RESULTS: Overall, 242 patients were analyzed, among whom 49 (20.2%) had PIAA. The median postoperative period of PIAA formation was 9 (range: 3-49) days. Among the 49 patients with PIAA, 25 (51.0%) underwent percutaneous ultrasound, computed tomography, or endoscopic ultrasound-guided interventions for PIAA. In the univariate analysis, preoperative indices representing abdominal fat mass (i.e., body mass index, subcutaneous fat area, and visceral fat area) were identified as predictive factors for PIAA; in the multivariate analysis, C-reactive protein (CRP) level (continuous variable) on postoperative day (POD) 3 (odds ratio: 1.189, 95.0% confidence interval: 1.111 - 1.274; P < 0.001) was the only independent and significant predictive factor for PIAA. CONCLUSIONS: CRP level on POD 3 was an independent and significant predictive factor for PIAA after distal pancreatectomy.

Long-term outcomes following ABO-incompatible living donor liver transplantation for acute liver failure: a single-center experience of over 20 years.

PURPOSE: Acute liver failure is a life-threatening condition for which ABO-incompatible living donor liver transplantation (ABOi-LDLT) is sometimes the only life-saving treatment option. We reviewed a single-center experience of adult ABOi-LDLT treatment for acute liver failure (ALF). METHODS: Preoperative treatment, immune indices (B cell marker, anti-donor blood-type antibody), and postoperative outcomes were compared between ALF and non-ALF groups. RESULTS: There were 5 and 33 patients in the ALF and non-ALF groups, respectively. The ALF group received higher doses of steroids, underwent more rounds of plasma exchange (PE), and underwent transplantation for ALF with a shorter interval following preoperative rituximab (RTx) administration (median: 2 vs 13 days; P < 0.05) than the non-ALF group. Preoperatively, CD19-positive lymphocytes in the peripheral blood were sufficiently depleted in all of the non-ALF group patients, whereas they were poorly depleted in the ALF group. Postoperatively, neither group suffered anti-donor blood-type antibody titer rebound or antibody-mediated rejection. The ALF group had a comparable 5-year survival rate to the non-ALF group (80.0% vs 77.9%). CONCLUSIONS: Despite the delayed preoperative administration of RTx, the ALF group showed an uneventful immunological response and acceptable long-term survival rate. Thus, ABOi-LDLT seems a viable treatment option for ALF.

Genomic analysis of familial pancreatic cancers and intraductal papillary mucinous neoplasms: A cross-sectional study.

Environmental and genetic factors play a critical role in the pathogenesis of pancreatic cancer, which is likely to follow a multistep process that includes intraductal papillary mucinous neoplasm. The pathogenesis of familial pancreatic cancer has been reported; however, epidemiological characteristics and causative genes remain unclear. This study aimed to determine the relationship between the family history of pancreatic cancer and tumor malignancy and identify novel susceptible germline variants of pancreatic cancer. We performed an epidemiologic study at our institute on a cohort of 668 patients with intraductal papillary mucinous neoplasm and 242 with pancreatic cancer but without associated intraductal papillary mucinous neoplasm stratified by family history of pancreatic cancer. Whole-exome sequencing was conducted for 10 patients from seven families with familial pancreatic cancer and intraductal papillary mucinous neoplasm. We found that patients who had intraductal papillary mucinous neoplasm with positive family history of pancreatic cancer within first-degree relatives were more likely to develop malignancy in a shorter period than those without family history. Duplicate frameshift variants in TET2 c.3180dupG (p.Pro1061fs) and ASXL1 c.1934dupG (p.Gly646fs) in one family and POLN c.1194dupT (p.Glu399fs) in another were identified as pathogenic truncating germline variants which were previously recognised susceptibility genes. Moreover, PDIA2 c.1403C>T (p.Pro468Leu) and DPYSL4 c.926C>A (p.Pro309Gln) were shared in four and two patients, respectively. In particular, PDIA2 was identified as a novel candidate for one of the deleterious variants of familial pancreatic cancer.

Indocyanine Green Fluorescence Navigation in Liver Surgery: A Systematic Review on Dose and Timing of Administration.

BACKGROUND: Indocyanine green (ICG) fluorescence has proven to be a high potential navigation tool during liver surgery; however, its optimal usage is still far from being standardized. METHODS: A systematic review was conducted on MEDLINE/PubMed for English articles that contained the information of dose and timing of ICG administration until February 2021. Successful rates of tumor detection and liver segmentation, as well as tumor/patient background and imaging settings were also reviewed. The quality assessment of the articles was performed in accordance with the Scottish Intercollegiate Guidelines Network (SIGN). RESULTS: Out of initial 311 articles, a total of 72 manuscripts were obtained. The quality assessment of the included studies revealed usually low; only 9 articles got qualified as high quality. Forty articles (55%) focused on open resections, whereas 32 articles (45%) on laparoscopic and robotic liver resections. Thirty-four articles (47%) described tumor detection ability, and 25 articles (35%) did liver segmentation ability, and the others (18%) did both abilities. Negative staining was reported (42%) more than positive staining (32%). For tumor detection, majority used the dose of 0.5 mg/kg within 14 days before the operation day, and an additional administration (0.02-0.5 mg/kg) in case of longer preoperative interval. Tumor detection rate was reported to be 87.4% (range, 43%-100%) with false positive rate reported to be 10.5% (range, 0%-31.3%). For negative staining method, the majority used 2.5 mg/body, ranging from 0.025 to 25 mg/body. For positive staining method, the majority used 0.25 mg/body, ranging from 0.025 to 12.5 mg/body. Successful segmentation rate was 88.0% (range, 53%-100%). CONCLUSION: The time point and dose of ICG administration strongly needs to be tailored case by case in daily practice, due to various tumor/patient backgrounds and imaging settings.

Examination of the characteristics of long-term survivors among patients with gallbladder cancer with liver metastasis who underwent surgical treatment: a retrospective multicenter study (ACRoS1406).

BACKGROUND: Gallbladder cancer (GBC) with liver metastasis is considered unresectable. However, there have been infrequent reports of long-term survival in patients with GBC and liver metastases. Therefore, we examined the characteristics of long-term survivors of gallbladder cancer with liver metastasis. METHODS: A retrospective multicenter study of 462 patients with GBC (mean age, 71 years; female, 51%) was performed. Although patients with pre-operatively diagnosed GBC and liver metastasis were generally excluded from resection, some cases identified during surgery were resected. RESULT: In patients with resected stage III/IV GBC (n = 193), the period 2007-2013 (vs. 2000-2006, hazard ratio 0.63), pre-operative jaundice (hazard ratio 1.70), ≥ 2 liver metastases (vs. no liver metastasis, hazard ratio 2.11), and metastasis to the peritoneum (vs. no peritoneal metastasis, hazard ratio 2.08) were independent prognostic factors for overall survival, whereas one liver metastasis (vs. no liver metastasis) was not. When examining the 5-year overall survival and median survival times by liver metastasis in patients without peritoneal metastasis or pre-operative jaundice, those with one liver metastasis (63.5%, not reached) were comparable to those without liver metastasis (40.4%, 33.0 months), and was better than those with ≥ 2 liver metastases although there was no statistical difference (16.7%, 9.0 months). According to the univariate analysis of resected patients with GBC and liver metastases (n = 26), minor hepatectomy, less blood loss, less surgery time, papillary adenocarcinoma, and T2 were significantly associated with longer survival. Morbidity of Clavien-Dindo classification ≤ 2 and received adjuvant chemotherapy were marginally not significant. Long-term survivors (n = 5) had a high frequency of T2 tumors (4/5), had small liver metastases near the gallbladder during or after surgery, underwent minor hepatectomy without postoperative complications, and received postoperative adjuvant chemotherapy. CONCLUSIONS: Although there is no surgical indication for GBC with liver metastasis diagnosed pre-operatively, minor hepatectomy and postoperative chemotherapy may be an option for selected patients with T2 GBC and liver metastasis identified during or after surgery who do not have other poor prognostic factors.

Reappraisal of liver transplantation for erythropoietic protoporphyria: A deadly combination of disease recurrence and biliary complication.

BACKGROUND: Erythropoietic protoporphyria (EPP) is a rare inherited disorder that causes the accumulation of protoporphyrin in the erythrocytes, skin, and liver. Severe protoporphyric hepatopathy results in liver failure, requiring both liver and bone marrow transplantation as a life-saving procedure and to correct the underlying enzymatic defect, respectively. CASE PRESENTATION: We report a 20-year-old man who underwent split liver transplantation using a right trisegment and caudate lobe graft for EPP-induced liver failure, but succumbed to a deadly combination of early relapse of EPP and subsequent, intractable, late-onset bile leakage from the cut surface of segment 4. EPP recurrence most likely created a high-risk situation for bile leakage from the non-communicating bile ducts of segment 4; therefore, this case shed light on the potential relationship between EPP recurrence and biliary complications. CONCLUSION: Physicians should recognize the potentially rapid and life-threatening progression of protoporphyric hepatopathy that leads to liver failure. For young patients with EPP, LT and sequential BMT should thoroughly be considered by a multidisciplinary team as soon as hepatic reserve deterioration becomes evident. Split liver transplantation should preferably be avoided and appropriate post-transplant management is critical before protoporphyrin depositions to the bile duct and hepatocyte causes irreversible damage to the liver graft.

Reconsideration of operative indications in pancreatic neuroendocrine neoplasms.

BACKGROUND: The incidence of pancreatic neuroendocrine neoplasm (PNEN) has been increasing. Resection is typically indicated for PNEN, regardless of its size; however, the indications for its resection are controversial. This study aimed to evaluate the treatment results of surgical resection of PNEN at our institute. METHODS: In this single-center, retrospective, case-control study, 87 patients who underwent PNEN resection and 17 patients with PNEN who did not undergo surgical resection between 1993 and 2020 were included in this study. Clinical characteristics and outcomes were reviewed and statistically compared. Survival was also estimated for the patients in each cohort. RESULTS: Seventeen patients who underwent resection (20%) had lymph node metastasis. Tumors measuring ≥ 2.0 cm and multiple lesions were identified as independent predictors for lymph node metastasis (odds ratio [OR] 17.3, 95% confidence interval [CI] 3.0-100.0, p = 0.001 and OR 8.7, 95% CI 1.5-52.0, p = 0.018, respectively). There was a significant difference in the survival curves depending on the presence or absence of lymph node metastasis (5-year overall survival 74.7% vs. 94.3%, p < 0.001; 5-year recurrence-free survival: 66.3% vs. 93.6%, p < 0.001). All 17 PNEN cases under observation with a median 8 mm (range 5-23) tumor size for a median of 34 (range 2.4-114) months showed slight morphological change with a median tumor growth rate of 0.15 mm (range 0-3.33) per year. CONCLUSION: Patients with tumors measuring ≥ 2.0 cm have a high probability of lymph node metastasis or recurrence, thereby requiring resection. PNEN measuring < 1.0 cm may be acceptable for observation.

The hypotaurine-taurine pathway as an antioxidative mechanism in patients with acute liver failure.

The liver has been thought to protect against oxidative stress through mechanisms involving reduced glutathione (GSH) that consumes high-energy phosphor-nucleotides on its synthesis. However, hepatoprotective mechanisms in acute liver failure (ALF) where the phosphor-nucleotides are decreased in remain to be solved. Liver tissues were collected from patients with ALF and liver cirrhosis (LC) and living donors (HD) who had undergone liver transplantation. Tissues were used for metabolomic analyses to determine metabolites belonging to the central carbon metabolism, and to determine sulfur-containing metabolites. ALF and LC exhibited a significant decline in metabolites of glycolysis and pentose phosphate pathways and high-energy phosphor-nucleotides such as adenosine triphosphate as compared with HD. Conversely, methionine, S-adenosyl-l-methionine, and the ratio of serine to 3-phosphoglycerate were elevated significantly in ALF as compared with LC and HD, suggesting a metabolic boost from glycolysis towards trans-sulfuration. Notably in ALF, the increases in hypotaurine (HTU) + taurine (TU) coincided with decreases in the total amounts of reduced and oxidized glutathione (GSH + 2GSSG). Plasma NH3 levels correlated with the ratio of HTU + TU to GSH + 2GSSG. Increased tissue levels of HTU + TU vs total glutathione appear to serve as a biomarker correlating with hyperammonemia, suggesting putative roles of the HTU-TU pathway in anti-oxidative protective mechanisms.

Spatial-light-modulator-based optical-fiber joint switch for few-mode multicore fibers.

To realize simplified cost-efficient optical networks with routing flexibility and scaling potential, a spatial-light-modulator-based optical-fiber joint switch for few-mode multicore fibers is proposed herein, which can route all spatial channels together as a unit. Numerical simulations and experiments were performed, and the results show that the signal paths for a 6-mode 19-core fiber can be simultaneously switched to the target output ports using the proposed method, and the mode-field patterns of the diffracted light can be maintained after joint switching. Further, the maximum port crosstalk can be reduced considerably from -11.6 to -25.1 dB by changing the position of the output port in the proposed method.

Indication for resection and possibility of observation for intraductal papillary mucinous neoplasm with high-risk stigmata.

BACKGROUND/OBJECTIVES: According to the revised international intraductal papillary mucinous neoplasm (IPMN) guidelines (2017), the indication for surgery is based on risk classification. However, some IPMNs with high-risk stigmata (HRS) can be observed for long periods without resection. Hence, we need to reconsider the risk stratification, and this study aimed to propose a novel risk stratification for HRS-IPMNs. METHODS: We enrolled 328 patients diagnosed with IPMN using endoscopic ultrasound between 2012 and 2019. We compared clinicopathological features between HRS and worrisome features (WF) and evaluated outcomes of HRS-IPMN. RESULTS: Fifty-three patients (HRS 38, WF 15) underwent resection at initial diagnosis and 275 patients were observed. Following observation for 30 months, 22 patients (17 HRS, 5 WF) underwent resection. Analysis of resected IPMNs (n = 75) revealed that HRS had dominantly pancreatobiliary mucin subtype. Pancreatobiliary-type IPMN had larger nodule sizes and lymphatic invasion and high recurrence with poor prognosis. Seventy-four patients were diagnosed with HRS, 55 underwent resection, and 19 continue to be observed. The resected group had larger nodule sizes (median 8 mm vs. 5 mm; P = 0.060), whereas the observed group had more main pancreatic duct (MPD) dilation (median 10 mm vs. 5 mm; P = 0.005). In the resected HRS group, only patients with MPD dilation ≥10 mm (n = 10) had no recurrence but had a favorable prognosis compared with those nodule size ≥5 mm (n = 45). CONCLUSIONS: Large nodule size may be associated with pancreatobiliary subtype and poor prognosis; however, patients with MPD dilation ≥10 mm with nodule size <5 mm did not require resection.

Clinical impact of intraoperative bile leakage during laparoscopic liver resection.

BACKGROUND: Despite the increasing number of laparoscopic liver resection (LLR) procedures, postoperative bile leakage (POBL) remains a major complication. We occasionally experienced intraoperative bile leakage (IOBL) during LLR and managed it within the restrictions of laparoscopic surgery. However, there have been no reports about IOBL in LLR. We therefore investigated the impact of IOBL on postoperative outcomes and its predictive factors. METHODS: We reviewed 137 patients who underwent LLR from April 2016 to March 2019 at our institute and assigned them to IOBL-positive or IOBL-negative groups. We compared clinicopathological characteristics and perioperative outcomes. Patients were further divided into four groups according to IOBL pattern, and the frequency of POBL in each was calculated. Predictors of IOBL were identified using multivariate logistic regression analysis. RESULTS: There were 30 and 107 patients in the IOBL-positive and IOBL-negative groups, respectively. In the IOBL-positive group, operative time and postoperative hospital stays were significantly longer (P < 0.001). The frequency of POBL was significantly higher in the IOBL-positive group (P = 0.006). The IOBL-positive group was divided into two subgroups: IOBL from the transected parenchyma (IOBL-TP, n = 18) and from the main Glissonean pedicle (IOBL-mGP, n = 12). The IOBL-negative group was divided into two subgroups: bile staining in the mGP (BS-mGP, n = 9) and no change (NC, n = 98). POBL occurred in 11% (n = 2/18) of patients with IOBL-TP, 25% (n = 3/12) of those with IOBL-mGP, 11% (n = 1/9) of those with BS-mGP, and 1% (n = 1/98) of those with NC. Age, diabetes mellitus, indocyanine green retention rate, and Glissonean approach were predictors of IOBL (P < 0.05). CONCLUSIONS: IOBL was relatively common during LLR and resulted in a higher incidence of POBL. Depending on the predictive factors, IOBL must be promptly identified and appropriately managed.

Clinical Impact of Portal Vein Distance on Computed Tomography for Postoperative Pancreatic Fistula after Pancreatoduodenectomy.

BACKGROUND: Pancreatic fistulas remain a significant concern after pancreatectomy owing to the associated high risk of mortality and high costs. It is not possible to perform preoperative risk stratification for all patients. This study aimed to evaluate the usefulness of the measurement of portal vein (PV) distance as a predictive indicator of pancreatic fistula development after pancreatoduodenectomy and compare it with the usefulness of other indicators such as body mass index (BMI), and abdominal fat area. METHODS: Patient characteristics, preoperative laboratory data, radiographic findings, and their association with pancreatic fistula development after pancreatoduodenectomy were analyzed for 157 patients who underwent resection during 2011-2017. Clinically relevant postoperative pancreatic fistulas (CR-POPF) were defined as Grade B or C fistulas based on the International Study Group of Pancreatic Surgery (ISGPS) 2016 consensus. RESULTS: CR-POPF developed in 38 patients (24.2%). Multivariate logistic regression indicated that PV distance and BMI were potential candidates for predictive models for pancreatic fistula development, and small pancreatic duct diameter, diabetes mellitus development, and pathology of non-pancreatic cancers were independent factors for CR-POPF. When comparing the two risk models (PV distance- and BMI-based models), the PV distance-derived risk model was compatible to the BMI-based stratification models (area under the curve 0.831 vs. 0.830). CONCLUSIONS: PV distance was confirmed to be a useful risk predictor for CR-POPF. This research highlighted the efficacy of abdominal thickness measurement, which is simple and easily applicable in the clinical setting.

Efficacy of the Milan criteria as a prognostic factor in patients with colorectal liver metastases.

PURPOSE: This study aimed to apply the principles of the "Milan criteria" to patients undergoing hepatic resection for CRLM and to evaluate the efficacy of prognostic factors. METHODS: The medical records of consecutive patients who underwent curative resection for CRLM from April 2007 to April 2019 were retrospectively reviewed. Time to aggressive treatment failure (TATF) was defined as the time interval from the initial surgery until the first unresectable recurrence or recurrence that could only be treated with doublet or lower dose chemotherapy, or death. The risk factors associated with recurrence-free survival (RFS), TSF, TATF, and overall survival (OS) were evaluated. RESULTS: On univariate analysis, the Milan criteria significantly predicted long-term OS, TATF, TSF, and RFS. Moreover, the Milan criteria were able to stratify patients with CRLM into distinct prognostic groups with regard to long-term OS, TATF, TSF, and RFS. CONCLUSIONS: Milan criteria, a simple index, are a factor contributing to all the survival time and are a very important factor in discussing the prognosis of CRLM.