Simulation of rear surface contamination for a simple bluff body

Predicting the accumulation of material on the rear surfaces of square-backed cars is important to vehicle manufacturers, as this progressively compromises rear vision, vehicle visibility and aesthetics. It also reduces the effectiveness of rear mounted cameras. Here, this problem is represented by a simple bluff body with a single sprayer mounted centrally under its rear trailing edge. A Very Large Eddy Simulation (VLES) solver is used to simulate both the aerodynamics of the body and deposition of contaminant. Aerodynamic drag and lift coefficients were predicted to within +1.3% and −4.2% of their experimental values, respectively. Wake topology was also correctly captured, resulting in a credible prediction of the rear surface deposition pattern. Contaminant deposition is mainly driven by the lower part of the wake ring vortex, which advects material back onto the rear surface. This leads to a maximum below the rear stagnation point and an association with regions of higher base pressure. The accumulation of mass is linear with time; the relative distribution changing little as the simulation progresses, implying that shorter simulations can be compared to longer experiments. Further, the rate of accumulation quickly reaches a settled mean value, suggesting utility as a metric for assessing different vehicles

Emergency management in patients with late hemorrhage after pancreatoduodenectomy for a periampullary tumor

The mortality rate due to late hemorrhage after surgery for periampullary tumors is high, especially in patients with anastomotic leakage. Patients usually require emergency intervention for late hemorrhage. In this study patients with late hemorrhage and their outcomes were analyzed. Furthermore, independent predictors for late hemorrhage, the need for emergency intervention, and type of intervention are reported. From a prospective database that includes 1,035 patients who underwent pancreatoduodenectomy for periampullary tumors between 1992 and 2012, patients with late hemorrhage (>24 h after index operation) were identified. Patient, disease-specific, and operation characteristics, type of intervention, and outcomes were analyzed. Emergency intervention was defined as surgical or radiological intervention in hemodynamically unstable patients. Of the 47 patients (4.5 %) with late hemorrhage, pancreatic fistula was an independent predictor for developing late hemorrhage (OR 10.2). The mortality rate in patients with late hemorrhage was 13 % compared with 1.5 % in all patients without late hemorrhage. Twenty patients required emergency intervention; 80 % underwent primary radiological intervention and 20 % primary surgical intervention. Extraluminal location of the bleeding (OR 5.6) and occurrence of a sentinel bleed (OR 6.6) are indications for emergency intervention. The type of emergency intervention needed for late hemorrhage is unpredictable. Radiological intervention is preferred, but if it fails, immediate change to surgical treatment is mandatory. This can be difficult to manage but possible when both radiological and surgical interventions are in close proximity such as in a hybrid operating room and should be considered in the emergency management of patients with late hemorrhag

A Nationwide Comparison of Laparoscopic and Open Distal Pancreatectomy for Benign and Malignant Disease

BACKGROUND: Cohort studies from expert centers suggest that laparoscopic distal pancreatectomy (LDP) is superior to open distal pancreatectomy (ODP) regarding postoperative morbidity and length of hospital stay. But the generalizability of these findings is unknown because nationwide data on LDP are lacking. STUDY DESIGN: Adults who had undergone distal pancreatectomy in 17 centers between 2005 and 2013 were analyzed retrospectively. First, all LDPs were compared with all ODPs. Second, groups were matched using a propensity score. Third, the attitudes of pancreatic surgeons toward LDP were surveyed. The primary outcome was major complications (Clavien-Dindo grade >= III). RESULTS: Among 633 included patients, 64 patients (10%) had undergone LDP and 569 patients (90%) had undergone ODP. Baseline characteristics were comparable, except for previous abdominal surgery and mean tumor size. In the full cohort, LDP was associated with fewer major complications (16% vs 29%; p = 0.02) and a shorter median [interquartile range, IQR] hospital stay (8 days [7-12 days] vs 10 days [8-14 days]; p = 0.03). Of all LDPs, 33% were converted to ODP. Matching succeeded for 63 LDP patients. After matching, the differences in major complications (9 patients [14%] vs 19 patients [30%]; p = 0.06) and median [IQR] length of hospital stay (8 days [7-12 days] vs 10 days [8-14 days]; p = 0.48) were not statistically significant. The survey demonstrated that 85% of surgeons welcomed LDP training. CONCLUSIONS: Despite nationwide underuse and an impact of selection bias, outcomes of LDP seemed to be at least noninferior to ODP. Specific training is welcomed and could improve both the use and outcomes of LDP. (C) 2015 by the American College of Surgeon

A nationwide comparison of laparoscopic and open distal pancreatectomy for benign and malignant disease

Cohort studies from expert centers suggest that laparoscopic distal pancreatectomy (LDP) is superior to open distal pancreatectomy (ODP) regarding postoperative morbidity and length of hospital stay. But the generalizability of these findings is unknown because nationwide data on LDP are lacking. Adults who had undergone distal pancreatectomy in 17 centers between 2005 and 2013 were analyzed retrospectively. First, all LDPs were compared with all ODPs. Second, groups were matched using a propensity score. Third, the attitudes of pancreatic surgeons toward LDP were surveyed. The primary outcome was major complications (Clavien-Dindo grade ≥III). Among 633 included patients, 64 patients (10%) had undergone LDP and 569 patients (90%) had undergone ODP. Baseline characteristics were comparable, except for previous abdominal surgery and mean tumor size. In the full cohort, LDP was associated with fewer major complications (16% vs 29%; p = 0.02) and a shorter median [interquartile range, IQR] hospital stay (8 days [7-12 days] vs 10 days [8-14 days]; p = 0.03). Of all LDPs, 33% were converted to ODP. Matching succeeded for 63 LDP patients. After matching, the differences in major complications (9 patients [14%] vs 19 patients [30%]; p = 0.06) and median [IQR] length of hospital stay (8 days [7-12 days] vs 10 days [8-14 days]; p = 0.48) were not statistically significant. The survey demonstrated that 85% of surgeons welcomed LDP training. Despite nationwide underuse and an impact of selection bias, outcomes of LDP seemed to be at least noninferior to ODP. Specific training is welcomed and could improve both the use and outcomes of LD

A nationwide comparison of laparoscopic and open distal pancreatectomy for benign and malignant disease

Background Cohort studies from expert centers suggest that laparoscopic distal pancreatectomy (LDP) is superior to open distal pancreatectomy (ODP) regarding postoperative morbidity and length of hospital stay. But the generalizability of these findings is unknown because nationwide data on LDP are lacking. Study Design Adults who had undergone distal pancreatectomy in 17 centers between 2005 and 2013 were analyzed retrospectively. First, all LDPs were compared with all ODPs. Second, groups were matched using a propensity score. Third, the attitudes of pancreatic surgeons toward LDP were surveyed. The primary outcome was major complications (Clavien-Dindo grade ≥III). Results Among 633 included patients, 64 patients (10%) had undergone LDP and 569 patients (90%) had undergone ODP. Baseline characteristics were comparable, except for previous abdominal surgery and mean tumor size. In the full cohort, LDP was associated with fewer major complications (16% vs 29%; p = 0.02) and a shorter median [interquartile range, IQR] hospital stay (8 days [7-12 days] vs 10 days [8-14 days]; p = 0.03). Of all LDPs, 33% were converted to ODP. Matching succeeded for 63 LDP patients. After matching, the differences in major complications (9 patients [14%] vs 19 patients [30%]; p = 0.06) and median [IQR] length of hospital stay (8 days [7-12 days] vs 10 days [8-14 days]; p = 0.48) were not statistically significant. The survey demonstrated that 85% of surgeons welcomed LDP training. Conclusions Despite nationwide underuse and an impact of selection bias, outcomes of LDP seemed to be at least noninferior to ODP. Specific training is welcomed and could improve both the use and outcomes of LDP

A Nationwide Comparison of Laparoscopic and Open Distal Pancreatectomy for Benign and Malignant Disease

BACKGROUND: Cohort studies from expert centers suggest that laparoscopic distal pancreatectomy (LDP) is superior to open distal pancreatectomy (ODP) regarding postoperative morbidity and length of hospital stay. But the generalizability of these findings is unknown because nationwide data on LDP are lacking. STUDY DESIGN: Adults who had undergone distal pancreatectomy in 17 centers between 2005 and 2013 were analyzed retrospectively. First, all LDPs were compared with all ODPs. Second, groups were matched using a propensity score. Third, the attitudes of pancreatic surgeons toward LDP were surveyed. The primary outcome was major complications (Clavien-Dindo grade >/=III). RESULTS: Among 633 included patients, 64 patients (10%) had undergone LDP and 569 patients (90%) had undergone ODP. Baseline characteristics were comparable, except for previous abdominal surgery and mean tumor size. In the full cohort, LDP was associated with fewer major complications (16% vs 29%; p = 0.02) and a shorter median [interquartile range, IQR] hospital stay (8 days [7-12 days] vs 10 days [8-14 days]; p = 0.03). Of all LDPs, 33% were converted to ODP. Matching succeeded for 63 LDP patients. After matching, the differences in major complications (9 patients [14%] vs 19 patients [30%]; p = 0.06) and median [IQR] length of hospital stay (8 days [7-12 days] vs 10 days [8-14 days]; p = 0.48) were not statistically significant. The survey demonstrated that 85% of surgeons welcomed LDP training. CONCLUSIONS: Despite nationwide underuse and an impact of selection bias, outcomes of LDP seemed to be at least noninferior to ODP. Specific training is welcomed and could improve both the use and outcomes of LDP

Oncological Safety and Potential Cost Savings of Routine vs Selective Histopathological Examination After Appendectomy: Results of the Multicenter, Prospective, Cross-Sectional FANCY Study

Objective: To investigate the oncological safety and potential cost savings of selective histopathological examination after appendectomy. Background: The necessity of routine histopathological examination after appendectomy has been questioned, but prospective studies investigating the safety of a selective policy are lacking. Methods: In this multicenter, prospective, cross-sectional study, inspection and palpation of the (meso)appendix was performed by the surgeon in patients with suspected appendicitis. The surgeon's opinion on additional value of histopathological examination was reported before sending all specimens to the pathologist. Main outcomes were the number of hypothetically missed appendiceal neoplasms with clinical consequences benefiting the patient (upper limit two-sided 95% confidence interval below 3:1000 considered oncologically safe) and potential cost savings after selective histopathological examination. Results: Seven thousand three hundred thirty-nine patients were included. After a selective policy, 4966/7339 (67.7%) specimens would have been refrained from histopathological examination. Appendiceal neoplasms with clinical consequences would have been missed in 22/4966 patients. In 5/22, residual disease was completely resected during additional surgery. Hence, an appendiceal neoplasm with clinical consequences benefiting the patient would have been missed in 1.01:1000 patients (upper limit 95% confidence interval 1.61:1000). In contrast, twice as many patients (10/22) would not have been exposed to potential harm due to re-resections without clear benefit, whereas consequences were neither beneficial nor harmful in the remaining seven. Estimated cost savings established by replacing routine for selective histopathological examination were 725,400 per 10,000 patients. Conclusions: Selective histopathological examination after appendectomy for suspected appendicitis is oncologically safe and will likely result in a reduction of pathologists' workload, less costs, and fewer re-resections without clear benefit