Anomalous Mechanical and Electrical Interplay in a Covalent Organic Framework Monolayer Membrane.

Ion transport through nanoconfinement, driven by both electrical and mechanical forces, has drawn ever-increasing attention, due to its high similarity to stress-sensitive ion channels in biological systems. Previous studies have reported only pressure-induced enhancement in ion conductance in low-permeable systems such as nanotubes, nanoslits, or single nanopores. This enhancement is generally explained by the ion accumulation caused by the capacitive effect in low-permeable systems. Here, we fabricate a highly permeable COF monolayer membrane to investigate ion transport behavior driven by both electrical and mechanical forces. Our results show an anomalous conductance reduction activated by external mechanical force, which is contrary to the capacitive effect-dominated conductance enhancement observed in low-permeable nanopores or channels. Through simulations, we uncovered a distinct electrical-mechanical interplay mechanism that depends on the relative rate between the ion diffusion from the boundary layer to the membrane surface and the ion transport through the membrane. The high pore density of the COF monolayer membrane reduces the charge accumulation caused by the capacitive effect, resulting in fewer accumulated ions near the membrane surface. Additionally, the high membrane permeability greatly accelerates the dissipation of the accumulated ions under mechanical pressure, weakening the effect of the capacitive layer on the streaming current. As a result, the ions accumulated on the electrodes, rather than in the capacitive layer, dominating the streaming current and giving rise to a distinct electrical-mechanical interplay mechanism compared to that in low-permeable nanopores or channels. Our study provides new insights into the interplay between electrical and mechanical forces in ultra-permeable systems.

A Risk-Prediction Platform for Acute Kidney Injury and 30-Day Readmission After Colorectal Surgery.

INTRODUCTION: Few known risk factors for certain surgical complications are prospectively analyzed to ascertain their influence on outcomes. Health systems can use integrated machine-learning-derived algorithms to provide information regarding patients' risk status in real time and pair this data with interventions to improve outcomes. The purpose of this work was to evaluate whether real-time knowledge of patients' calculated risk status paired with a stratified intervention was associated with a reduction in acute kidney injury and 30-d readmission following colorectal surgery. METHODS: Unblinded, retrospective study, evaluating the impact of an electronic health record-integrated and autonomous algorithm-based clinical decision support tool (KelaHealth, San Francisco, California) on acute kidney injury and 30-d readmission following colorectal surgery at a single academic medical center between January 1, 2020, and December 31, 2020, relative to a propensity-matched historical cohort (2014-2018) prior to algorithm integration (January 11, 2019). RESULTS: 3617 patients underwent colorectal surgery during the control period and 665 underwent surgery during the treatment period; 1437 historical control patients were matched to 479 risk-based patients for the study. Utilization of the risk-based management platform was associated with a 2.5% decrease in the rate of acute kidney injury (11.3% to 8.8%) and 3.1% decrease in rate of readmissions (12% to 8.9%). CONCLUSIONS: In this study, we found significant reductions in postoperative acute kidney injury (AKI) and unplanned readmissions after the implementation of an algorithm based clinical decision support tool that risk-stratified populations and offered stratified interventions. This opens up an opportunity for further investigation in translating similar risk platform approaches across surgical specialties.

Deep Learning-Based Risk Model for Best Management of Closed Groin Incisions After Vascular Surgery.

BACKGROUND: Reduced surgical site infection (SSI) rates have been reported with use of closed incision negative pressure therapy (ciNPT) in high-risk patients. METHODS: A deep learning-based, risk-based prediction model was developed from a large national database of 72,435 patients who received infrainguinal vascular surgeries involving upper thigh/groin incisions. Patient demographics, histories, laboratory values, and other variables were inputs to the multilayered, adaptive model. The model was then retrospectively applied to a prospectively tracked single hospital data set of 370 similar patients undergoing vascular surgery, with ciNPT or control dressings applied over the closed incision at the surgeon's discretion. Objective predictive risk scores were generated for each patient and used to categorize patients as "high" or "low" predicted risk for SSI. RESULTS: Actual institutional cohort SSI rates were 10/148 (6.8%) and 28/134 (20.9%) for high-risk ciNPT versus control, respectively (P < 0.001), and 3/31 (9.7%) and 5/57 (8.8%) for low-risk ciNPT versus control, respectively (P = 0.99). Application of the model to the institutional cohort suggested that 205/370 (55.4%) patients were matched with their appropriate intervention over closed surgical incision (high risk with ciNPT or low risk with control), and 165/370 (44.6%) were inappropriately matched. With the model applied to the cohort, the predicted SSI rate with perfect utilization would be 27/370 (7.3%), versus 12.4% actual rate, with estimated cost savings of $231-$458 per patient. CONCLUSIONS: Compared with a subjective practice strategy, an objective risk-based strategy using prediction software may be associated with superior results in optimizing SSI rates and costs after vascular surgery.

Preoperative radiation therapy in the surgical management of gastric and junctional adenocarcinoma: Should lymph node retrieval guidelines be altered?

BACKGROUND: Although surgery remains the cornerstone of gastric cancer therapy, the use of radiation therapy (RT) is increasingly being employed to optimize outcomes. We sought to assess outcomes following use of RT for the treatment of gastric adenocarcinoma. METHODS: Using the National Cancer Data Base (NCDB) from 1998 to 2012, all patients with resected gastric adenocarcinoma were identified. Patients were stratified into four groups based on preoperative therapy: RT alone, chemotherapy only, chemoradiotherapy (CRT), and no preoperative therapy. Overall survival was estimated using multivariate Cox proportional hazards model. Adjusted secondary outcomes include margin positivity, lymph node harvest, LOS, 30-day readmission and mortality. RESULTS: A total of 10 019 patients met study criteria. In the unadjusted analysis, patients undergoing CRT compared to chemotherapy alone had fewer positive margins (7.9% vs 15.9%; P < 0.001), increased negative LNs (54.6% vs 37.7%; P < 0.001) with reduced LN retrieval (mean: 13.5 vs 19.6; P < 0.01). After multivariate adjustment, there was no survival benefit to any preoperative therapy; however, preoperative RT/CRT remained associated with decreased LN retrieval. CONCLUSIONS: The results support previous reports on preoperative RT resulting in decreased margin positivity. This study highlights the need to reconsider practice guidelines regarding appropriate lymphadenectomy in the setting of preoperative RT given reduced LN retrieval.

Solid Pseudopapillary Neoplasm of the Pancreas in Children and Adults: A National Study of 369 Patients.

BACKGROUND: Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare tumor in children, with current evidence limited to single-center studies. We examined treatment and clinical outcomes for pediatric and adult SPN with a national data set. METHODS: The 2004 to 2013 National Cancer Data Base was queried to identify all patients diagnosed with SPN. The cohort was stratified by age (pediatric and adult) defined as below 18 years and 18 years and above, respectively. Baseline characteristics and unadjusted outcomes were compared. RESULTS: We identified 21 pediatric and 348 adult patients with SPN. Both groups displayed similar demographic composition. Patients were commonly female (90.5% [pediatric] vs. 85.9% [adult], P=0.56) and white (66.7% vs. 68.3%, P=0.74). Tumor location was similar between adults and children. Median tumor size was similar between children and adults (5.9 vs. 4.9 cm, P=0.41). Treatment strategies did not vary between groups. Partial pancreatectomy was the most common resection strategy (71.4% vs. 53.1%, P=0.80). Both groups experienced low mortality (0.0% vs. 0.7% at 5 y, P=0.31). CONCLUSIONS: This study provides the largest comparison of pediatric and adult SPN to date. Children with SPN have similar disease severity at presentation, receive similar treatments, and demonstrate equivalent postoperative outcomes compared with their adult counterparts.

Open versus laparoscopic portal lymphadenectomy in gallbladder cancer: is there a difference in lymph node yield?

BACKGROUND: Gallbladder cancer (GBC) is the most common biliary tract malignancy. Because it commonly metastasizes via lymphatics, portal lymphadenectomy should be included in oncologic resections. This study aimed to compare the oncologic equivalence of the laparoscopic versus open technique by evaluating lymph node (LN) yield. METHODS: The 2010-2012 National Cancer Data Base identified patients who underwent laparoscopic or open resection of GBC with dedicated lymphadenectomy. LN yield was compared by resection method. Variables associated with LN yield ≥3 were identified. RESULTS: Of 1524 patients identified, 52% were intended to undergo laparoscopic surgery, with 20% of these patients converted to open. Collection of ≥3 LNs following open resection (47%) was higher than for laparoscopic resection (34%), p < 0.001. Operations performed at high-volume (aOR:1.74, p < 0.001) and/or academic centers (aOR:1.70, p = 0.024) had superior LN yield. LN yield was not associated with overall survival (aHR:0.93, p = 0.493). CONCLUSIONS: In this analysis of national data, LN yield following laparoscopic resection for GBC was significantly lower than following open resection. Open resection is more frequently performed at academic centers, possibly to assure adequate oncologic resection. Enforcing consensus guidelines for lymphadenectomy in gallbladder cancer will optimize outcomes as minimally invasive approaches evolve.

Insurance Status, Not Race, is Associated With Use of Minimally Invasive Surgical Approach for Rectal Cancer.

OBJECTIVE: To determine the impact of race and insurance on use of minimally invasive (MIS) compared with open techniques for rectal cancer in the United States. BACKGROUND: Race and socioeconomic status have been implicated in disparities of rectal cancer treatment. METHODS: Adults undergoing MIS (laparoscopic or robotic) or open rectal resections for stage I to III rectal adenocarcinoma were included from the National Cancer Database (2010-2012). Multivariate analyses were employed to examine the adjusted association of race and insurance with use of MIS versus open surgery. RESULTS: Among 23,274 patients, 39% underwent MIS and 61% open surgery. Overall, 86% were white, 8% black, and 3% Asian. Factors associated with use of open versus MIS were black race, Medicare/Medicaid insurance, and lack of insurance. However, after adjustment for patient demographic, clinical, and treatment characteristics, black race was not associated with use of MIS versus open surgery [odds ratio [OR] 0.90, P = 0.07). Compared with privately insured patients, uninsured patients (OR 0.52, P < 0.01) and those with Medicare/Medicaid (OR 0.79, P < 0.01) were less likely to receive minimally invasive resections. Lack of insurance was significantly associated with less use of MIS in black (OR 0.59, P = 0.02) or white patients (OR 0.51, P < 0.01). However, among uninsured patients, black race was not associated with lower use of MIS (OR 0.96, P = 0.59). CONCLUSIONS: Insurance status, not race, is associated with utilization of minimally invasive techniques for oncologic rectal resections. Due to the short-term benefits and cost-effectiveness of minimally invasive techniques, hospitals may need to improve access to these techniques, especially for uninsured patients.

Going the Extra Mile: Improved Survival for Pancreatic Cancer Patients Traveling to High-volume Centers.

OBJECTIVE: This study compares outcomes following pancreaticoduodenectomy (PD) for patients treated at local, low-volume centers and those traveling to high-volume centers. BACKGROUND: Although outcomes for PD are superior at high-volume institutions, not all patients live in proximity to major medical centers. Theoretical advantages for undergoing surgery locally exist. METHODS: The 1998 to 2012 National Cancer Data Base was queried for T1-3N0-1M0 pancreatic adenocarcinoma patients who underwent PD. Travel distances to treatment centers were calculated. Overlaying the upper and lower quartiles of travel distance with institutional volume established short travel/low-volume (ST/LV) and long travel/high-volume (LT/HV) cohorts. Overall survival was evaluated. RESULTS: Of 7086 patients, 773 ST/LV patients traveled ≤6.3 (median 3.2) miles to centers performing ≤3.3 PDs yearly, and 758 LT/HV patients traveled ≥45 (median 97.3) miles to centers performing ≥16 PDs yearly. LT/HV patients had higher stage disease (P < 0.001), but lower margin positivity (20.5% vs 25.9%, P = 0.01) and improved lymphadenectomy (16 vs 11 nodes, P < 0.01). Moreover, LT/HV patients had shorter hospitalizations (9 vs 12 days, P < 0.01) and lower 30-day mortality (2.0% vs 6.3%, P < 0.01) with similar 30-day readmission rates (10.1% vs 9.8%, P = 0.83). Despite more advanced disease, LT/HV patients had superior unadjusted survival (20.3 vs 15.7 months). After adjustment, travel to a high-volume center remained associated with reduced long-term mortality (hazard ratio 0.75, P < 0.01). CONCLUSIONS: Despite an increased travel burden, patients treated at high-volume centers had improved perioperative outcomes, short-term mortality, and overall survival. These data support ongoing efforts to centralize care for patients undergoing PD.

Adjuvant Chemotherapy After Preoperative Chemoradiation Improves Survival in Patients With Locally Advanced Rectal Cancer.

BACKGROUND: Practice guidelines differ in their support of adjuvant chemotherapy use in patients who received preoperative chemoradiation for rectal cancer. OBJECTIVE: The purpose of this study was to evaluate the impact of adjuvant chemotherapy among patients with locally advanced rectal cancer who received neoadjuvant chemoradiation and surgery. DESIGN: This was a retrospective study. Multivariable Cox proportional hazard modeling was used to evaluate the adjusted survival differences. SETTINGS: Data were collected from the National Cancer Database. PATIENTS: Adults with pathologic stage II and III rectal adenocarcinoma who received neoadjuvant chemoradiation and surgery were included. MAIN OUTCOME MEASURES: Overall survival was measured. RESULTS: Among 12,696 patients included, 4023 (32%) received adjuvant chemotherapy. The use of adjuvant chemotherapy increased over the study period from 23% to 36%. Although older age and black race were associated with a lower likelihood of receiving adjuvant chemotherapy, patients with higher education level and stage III disease were more likely to receive adjuvant chemotherapy (all p < 0.05). At 7 years, overall survival was improved among patients who received adjuvant chemotherapy (60% vs. 55%; p < 0.001). After risk adjustment, the use of adjuvant chemotherapy was associated with improved survival (HR = 0.81 (95% CI, 0.72-0.91); p < 0.001). In the subgroup of patients with stage II disease, survival was also improved among patients who received adjuvant chemotherapy (68% vs 58% at 7 y; p < 0.001; HR = 0.70 (95% CI, 0.57-0.87); p = 0.002). Among patients with stage III disease, the use of adjuvant chemotherapy was associated with a smaller but persistent survival benefit (56% vs 51% at 7 y; p = 0.017; HR = 0.85 (95% CI, 0.74-0.98); p = 0.026). LIMITATIONS: The study was limited by its potential for selection bias and inability to compare specific chemotherapy regimens. CONCLUSIONS: The use of adjuvant chemotherapy among patients with rectal cancer who received preoperative chemoradiation conferred a survival benefit. This study emphasizes the importance of adjuvant chemotherapy in the management of rectal cancer and advocates for its increased use in the setting of neoadjuvant therapy. See Video Abstract at http://link.lww.com/DCR/A428.

Gallbladder abnormalities in children with metachromatic leukodystrophy.

BACKGROUND: Metachromatic leukodystrophy (MLD) is a lysosomal storage disease that leads to neurological deterioration and visceral involvement, including sulphatide deposition in the gallbladder wall. Using our institution's extensive experience in treating MLD, we examined the incidence of gallbladder abnormalities in the largest cohort of children with MLD to date. METHODS: We conducted a retrospective review of all children with MLD, adrenoleukodystrophy (ALD), or Krabbe disease who underwent hematopoietic stem cell transplantation (HSCT) at our institution between 1994 and 2015. Baseline characteristics and unadjusted outcomes were compared using the Kruskal-Wallis test for continuous variables and Pearson χ2 test for categorical variables, with significance defined as P < 0.05. RESULTS: In total, 87 children met study criteria: 29 children with MLD and 58 children with ALD or Krabbe disease. Children with MLD were more likely to demonstrate gallbladder abnormalities on imaging, both before HSCT (41.4% versus 5.2%, P < 0.001) and after HSCT (75.9% versus 41.4%, P = 0.002). Consequently, a larger proportion of children with MLD underwent surgical or interventional management of biliary disease (10.3% versus 3.4%, P = 0.03). CONCLUSIONS: Children with MLD have a significantly greater incidence of gallbladder abnormalities than children with other lysosomal storage diseases. Biliary disease should be considered in children with MLD who develop abdominal pain, and cholecystectomy should be considered for persistent, symptomatic gallbladder abnormalities.