Challenges of modeling current very large lahars at Nevado del Huila Volcano, Colombia

Nevado del Huila, a glacier-covered volcano in the South of Colombia's Cordillera Central, had not experienced any historical eruptions before 2007. In 2007 and 2008, the volcano erupted with phreatic and phreatomagmatic events which produced lahars with flow volumes of up to about 300 million m3 causing severe damage to infrastructure and loss of lives. The magnitude of these lahars and the prevailing potential for similar or even larger events, poses significant hazards to local people and makes appropriate modeling a real challenge. In this study, we analyze the recent lahars to better understand the main processes and then model possible scenarios for future events. We used lahar inundation depths, travel duration, and flow deposits to constrain the dimensions of the 2007 event and applied LAHARZ and FLO-2D for lahar modeling. Measured hydrographs, geophone seismic sensor data and calculated peak discharges served as input data for the reconstruction of flow hydrographs and for calibration of the models. For model validation, results were compared with field data collected along the Páez and Simbola Rivers. Based on the results of the 2007 lahar simulation, we modeled lahar scenarios with volumes between 300 million and 1 billion m3. The approach presented here represents a feasible solution for modeling high-magnitude flows like lahars and allows an assessment of potential future events and related consequences for population centers downstream of Nevado del Huil

Irreversible Electroporation in Pancreatic Cancer

Pancreatic cancer is the deadliest of the gastrointestinal tract with 5-year survival rates of less than 5%. Given common asymptomatic early disease course, most patients (50%) present with an already metastatic disease, while only 20% can undergo potentially curative resection. The remaining 30% present with locally advanced disease, defined as extended vascular encasement, where the risk of surgical therapy often outweighs its benefits. Traditional thermal local ablative modalities (RFA, MWA, or cryotherapy) have the disadvantage that they are not applicable in proximity to vital vascular structures, which are abundant in the peripancreatic region. Irreversible electroporation (IRE) is an emerging non-thermal alternative that induces apoptosis of tumor cells by the delivery of short repetitive impulses of high-voltage electric current. Given its mostly non-thermal modality, IRE is not hampered by a heat-sink effect and is applicable with little risk around vascular structures, bile and pancreatic ducts. Recent research suggests that local tumor destruction through IRE improves overall survival, progression-free survival and quality of life in patients with locally advanced pancreatic cancer

Roux-en-Y Drainage of the Pancreatic Stump Decreases Pancreatic Fistula After Distal Pancreatic Resection

Clinically relevant fistula after distal pancreatic resection occurs in 5-30% of patients, prolonging recovery and considerably increasing in-hospital stay and costs. We tested whether routine drainage of the pancreatic stump into a Roux-en-Y limb after distal pancreatic resection decreased the incidence of fistula. From October 2001, data of all patients undergoing pancreatic distal resection were entered in a prospective database. From June 2003 after resection, the main pancreatic duct and the pancreatic stump were oversewn, and in addition, anastomosed into a jejunal Roux-en-Y limb by a single-layer suture (n = 23). A drain was placed near the anastomosis, and all patients received octreotide for 5-7days postoperatively. The volume of the drained fluid was registered daily, and concentration of amylase was measured and recorded every other day. Patient demographics, hospital stay, pancreatic fistula incidence (≥30ml amylase-rich fluid/day on/after postoperative day 10), perioperative morbidity, and follow-up after discharge were compared with our initial series of patients (treated October 2001-May 2003) who underwent oversewing only (n = 20). Indications, patient demographics, blood loss, and tolerance of an oral diet were similar. There were four (20%) pancreatic fistulas in the "oversewn” group and none in the anastomosis group (p < 0.05). Nonsurgical morbidity, in-hospital stay, and follow-up were comparable in both group

Laparoscopic Appendectomy Outcomes on the Weekend and During the Week are no Different: A National Study of 151,774 Patients

Background: The "weekend effect” is defined as increased morbidity and mortality for patients admitted on weekends compared with weekdays. It has been observed for several diseases, including myocardial infarction and renal insufficiency; however, it has not yet been investigated for laparoscopic appendectomy in acute appendicitis—one of the most prevalent surgical diagnoses. Methods: The present study is based on the Nationwide Inpatient Sample (NIS) from 1999 to 2008. The following outcomes were compared between patients undergoing laparoscopic appendectomy for acute appendicitis admitted on weekdays versus weekends: severity of appendicitis, intraoperative and postoperative complications, conversion rate, in-hospital mortality, and length of hospital stay. Unadjusted and risk-adjusted generalized linear regression analyses were performed. Results: Overall, 151,774 patients were included, mean age was 39.6years, 52.6% (n=79,801) were male, and 25.3% (n=38,317) were admitted on weekends. After risk adjustment, the conversion rate was lower [odds ratio (OR): 0.94, p=0.004, number needed to harm (NNH): 244], whereas pulmonary complications (OR: 1.12, p=0.028, NNH: 649) and reoperations (OR: 1.21, p=0.013, NNH: 1,028) were slightly higher on weekends than on weekdays. Overall postoperative complications (OR: 1.03, p=0.24), mortality (OR: 1.37, p=0.075) and length of hospital stay (mean on weekday: 2.00days, weekends: 2.01days, p=0.29) were not statistically different. Conclusions: The present investigation provides evidence that no clinically significant "weekend effect” for patients undergoing laparoscopic appendectomy exists. Therefore, hospital or staffing policy changes are not justified based on the findings from this large national stud

Rak jelita grubego z potencjalnie resekcyjnymi przerzutami do wątroby: optymalizacja leczenia

Colorectal cancer is a common malignancy and often presents with synchronous or metachronous distant spread. For patients with hepatic metastases, resection is the principal curative option. Liberalization of the indications for hepatic resection has introduced a number of challenges related to the size, distribution, and number of metastases as well as the condition of the future liver remnant. Advances in systemic therapy have solidified its role as both an important adjunct to surgery and also for many patients as a mechanism to facilitate resection. In patients whose disease is marginally resectable as a consequence of the distribution of hepatic lesions that precludes complete resection or out of concern for the future liver remnant, a number of strategies have been advocated, including prehepatectomy systemic therapy, staged surgical approaches, ablative technologies, and preoperative portal vein embolization. It is the purpose of this review to discuss ways in which to optimize the treatment of patients with potentially resectable disease, specifically those who are judged to have “borderline” resectable situations.Rak jelita grubego jest często występującym nowotworem, w którego przebiegu mogą występować synchronicznie lub metachronicznie przerzuty odległe. Podstawową metodę leczenia w przypadku przerzutów do wątroby stanowi chirurgiczna resekcja. Rozszerzenie wskazań do leczenia operacyjnego przerzutów do wątroby przyniosło szereg wyzwań dotyczących wielkości przerzutów, ich lokalizacji i liczby, a także wydolności pozostawionego miąższu narządu. Postęp w leczeniu systemowym ugruntował rolę tej metody zarówno w postępowaniu uzupełniającym po leczeniu chirurgicznym, jak i indukcyjnym ułatwiającym resekcję przerzutów. U chorych z przerzutami o wątpliwej resekcyjności z powodu rozmieszczenia zmian w wątrobie wykluczającego doszczętne wycięcie przy zachowaniu akceptowalnej funkcji pozostawionego miąższu, podejmuje się próby stosowania różnych metod, w tym neoadiuwantowego leczenia systemowego, kilkuetapowych resekcji, a także ablacji i przedoperacyjnej embolizacji żyły wrotnej. W niniejszym opracowaniu przedstawiono strategie optymalizacji leczenia chorych z potencjalnie lub w szczególności z granicznie resekcyjnymi zmianami przerzutowymi w wątrobie

Cholecystectomy Concomitant with Laparoscopic Gastric Bypass: A Trend Analysis of the Nationwide Inpatient Sample from 2001 to 2008

Background: Gallstone formation is common in obese patients, particularly during rapid weight loss. Whether a concomitant cholecystectomy should be performed during laparoscopic gastric bypass surgery is still contentious. We aimed to analyze trends in concomitant cholecystectomy and laparoscopic gastric bypass surgery (2001-2008), to identify factors associated with concomitant cholecystectomy, and to compare short-term outcomes after laparoscopic gastric bypass with and without concomitant cholecystectomy. Methods: We used data from adults undergoing laparoscopic gastric bypass for obesity from the Nationwide Inpatient Sample. The Cochran-Armitage trend test was used to assess changes over time. Unadjusted and risk-adjusted generalized linear models were performed to assess predictors of concomitant cholecystectomy and to assess postoperative short-term outcomes. Results: A total of 70,287 patients were included: mean age was 43.1years and 81.6% were female. Concomitant cholecystectomy was performed in 6,402 (9.1%) patients. The proportion of patients undergoing concomitant cholecystectomy decreased significantly from 26.3% in 2001 to 3.7% in 2008 (p for trend < 0.001). Patients who underwent concomitant cholecystectomy had higher rates of mortality (unadjusted odds ratios [OR], 2.16; p = 0.012), overall postoperative complications (risk-adjusted OR, 1.59; p = 0.001), and reinterventions (risk-adjusted OR, 3.83; p < 0.001), less frequent routine discharge (risk-adjusted OR, 0.70; p = 0.05), and longer adjusted hospital stay (median difference, 0.4days; p < 0.001). Conclusions: Concomitant cholecystectomy and laparoscopic gastric bypass surgery have decreased significantly over the last decade. Given the higher rates of postoperative complications, reinterventions, mortality, as well as longer hospital stay, concomitant cholecystectomy should only be considered in patients with symptomatic gallbladder diseas

Adjuvant Radiotherapy in the Treatment of Invasive Intraductal Papillary Mucinous Neoplasm of the Pancreas: an Analysis of the Surveillance, Epidemiology, and End Results Registry

Background: Management and outcomes of patients with invasive intraductal papillary mucinous neoplasm (IPMN) of the pancreas are not well established. We investigated whether adjuvant radiotherapy (RT) improved cancer-specific survival (CSS) and overall survival (OS) among patients undergoing surgical resection for invasive IPMN. Methods: The Surveillance, Epidemiology, and End Results (SEER) registry was used in this retrospective cohort study. All adult patients with resection of invasive IPMN from 1988 to 2007 were included. CSS and OS were analyzed using Kaplan-Meier curves. Unadjusted and propensity-score-adjusted Cox proportional-hazards modeling were used for subgroup analyses. Results: 972 patients were included. Adjuvant RT was administered to 31.8% (n=309) of patients. There was no difference in overall median CSS or OS in patients who received adjuvant RT (5-year CSS: 26.5months; 5-year OS: 23.5months) versus those who did not (CSS: 28.5months, P=0.17; OS: 23.5months, P=0.23). Univariate predictors of survival were lymph node (LN) involvement, T4-classified tumors, and poorly differentiated tumor grade (all P<0.05). In the propensity-score-adjusted analysis, adjuvant RT was associated with improved 5-year CSS [hazard ratio (HR): 0.67, P=0.004] and 5-year OS (HR: 0.73, P=0.014) among all patients with LN involvement, though further analysis by T-classification demonstrated no survival differences among patients with T1/T2 disease; patients with T3/T4-classified tumors had improved CSS (HR: 0.71, P=0.022) but no difference in OS (HR: 0.76, P=0.06). Conclusion: On propensity-score-adjusted analysis, adjuvant RT was associated with improved survival in selected subsets of patients with invasive IPMN, particularly those with T3/T4 tumors and LN involvemen

Discrete Improvement in Racial Disparity in Survival among Patients with Stage IV Colorectal Cancer: a 21-Year Population-Based Analysis

Purpose Recently, multiple clinical trials have demonstrated improved outcomes in patients with metastatic colorectal cancer. This study investigated if the improved survival is race dependent. Patients and Methods Overall and cancer-specific survival of 77,490 White and Black patients with metastatic colorectal cancer from the 1988–2008 Surveillance Epidemiology and End Results registry were compared using unadjusted and multivariable adjusted Cox proportional hazard regression as well as competing risk analyses. Results Median age was 69 years, 47.4 % were female and 86.0 % White. Median survival was 11 months overall, with an overall increase from 8 to 14 months between 1988 and 2008. Overall survival increased from 8 to 14 months for White, and from 6 to 13 months for Black patients. After multivariable adjustment, the following parameters were associated with better survival: White, female, younger, better educated and married patients, patients with higher income and living in urban areas, patients with rectosigmoid junction and rectal cancer, undergoing cancer-directed surgery, having well/moderately differentiated, and N0 tumors (p<0.05 for all covariates). Discrepancies in overall survival based on race did not change significantly over time; however, there was a significant decrease of cancer-specific survival discrepancies over time between White and Black patients with a hazard ratio of 0.995 (95 % confidence interval 0.991–1.000) per year (p=0.03). Conclusion A clinically relevant overall survival increase was found from 1988 to 2008 in this population-based analysis for both White and Black patients with metastatic colorectal cancer. Although both White and Black patients benefitted from this improvement, a slight discrepancy between the two groups remained