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Introduction: Emergency department (ED) visits after surgery represent a significant cost burden on the healthcare system. Furthermore, many ED visits are related to issues of healthcare delivery services and may be avoidable. Few studies have assessed the reasons for ED visits after colorectal surgery. The main objectives of this study were to: (1) identify the reasons why patients presented to the ED within 30 postoperative days and (2) determine if these visits were potentially preventable., Methods: A retrospective chart review was conducted on elective major colorectal surgery cases performed in a single center between 01/2017 and 07/2019. Data collected included demographics, medical history, intraoperative details, postoperative complications, ED visits within 30 postoperative days, and readmissions. Each ED visit was assessed by two reviewers and graded on a scale adapted from the New York University ED algorithm. The gradings were: (1) non-emergent, (2) emergent but treatable in an ambulatory setting, (3) emergent/ED-care required but preventable if timely outpatient care was available, and (4) emergent/ED-care required and non-preventable. Grades 1-3 were deemed potentially preventable. Logistic regression identified independent predictors of potentially preventable visits., Results: Six hundred and twenty five patients were included in the final analysis. 110 (17.6%) patients presented to the ED within 30 days. The most common cause of ED visit were ileus/small bowel obstruction (SBO) (16.4%), superficial wound infection (15.5%), genitourinary issues (10.9%), and non-infectious gastrointestinal issues (nausea, malnutrition, diarrhea, high output stomas) (10.9%). After review, 51.8% of visits were considered potentially preventable (Grade 1-3). The most common causes of preventable ED visits were superficial wound infection (24.6%), non-infectious gastrointestinal issues (19.3%), and minor bleeding (14.0%). Creation of a new stoma was the only independent risk factor for potentially preventable ED visits (OR 2.14, 95%CI 1.03-4.47)., Conclusion: Approximately half of ED visits within 30 days of discharge were potentially preventable. These findings indicate a need to improve access to outpatient care to reduce preventable ED visits after elective colorectal surgery., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Strong nonlinearity of a self-resonant radio-frequency (rf) superconducting-quantum-interference-device (SQUID) meta-atom is explored via intermodulation (IM) measurements. Previous work in zero dc magnetic flux showed a sharp onset of IM response as the frequency sweeps through the resonance. A second onset at higher frequency was also observed, creating a prominent gap in the IM response. By extending those measurements to nonzero dc flux, different dynamics are revealed, including dc flux tunability of the aforementioned gaps and enhanced IM response near geometric resonance of the rf SQUID. These features observed experimentally are understood and analyzed theoretically through a combination of a steady-state analytical modeling and a full numerical treatment of the rf SQUID dynamics. The latter in addition predicts the presence of chaos in narrow parameter regimes. The understanding of intermodulation in rf SQUID metamaterials is important for producing low-noise amplification of microwave signals and tunable filters.

Background: Surgery for low rectal cancer can be associated with severe bowel dysfunction and impaired quality of life. It is important to determine how patients value the trade-off between anorectal dysfunction versus abdominoperineal resection. Therefore, the objective was to determine patients' preferences for treatment for low rectal cancer., Methods: Ambulatory patients without colorectal cancer at a single high-volume academic colorectal referral center from September 2019 to March 2020 were included. Patients with prior stoma or malignancy were excluded. Participants were presented with a hypothetic scenario describing a low rectal cancer. A threshold task identified preferences for functional and oncologic outcomes for sphincter preservation versus abdominoperineal resection., Results: A total of 123 patients were recruited. Patients preferred abdominoperineal resection over sphincter preservation if there were more than a mean of 6.7 (standard deviation 4.0) daily bowel movements, 1.9 (standard deviation 2.6) daily episodes of stool incontinence, and 6.5 (standard deviation 3.2) gas incontinence. Abdominoperineal resection was preferred over sphincter preservation in 38% if daily activities were altered owing to fecal urgency. Patients were willing to accept a 10% (interquartile range, 5-25) absolute increase in risk of margin involvement with sphincter preservation to avoid abdominoperineal resection. Abdominoperineal resection was the preferred option overall for 18% of patients., Conclusion: An important proportion of patients would prefer abdominoperineal resection over sphincter preservation owing to the impairments in anorectal function associated with sphincter preservation. The decision to perform sphincter preservation or abdominoperineal resection should consider how the patients' value functional outcomes with a low anastomosis., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: The aim of this study is to examine the interaction between preoperative anemia and perioperative transfusions with postoperative morbidity and mortality among patients undergoing gastrectomy for cancer., Materials and Methods: The American College of Surgeons National Surgical Quality Improvement Program database was queried from 2005 to 2016. Restricted cubic splines modeled the nonlinear relationship between preoperative hematocrit (Hct) and 30-day overall morbidity, sepsis, and mortality. Preoperative Hct was categorized based on cut points for the three models. Multiple regression modeling examined the interactive effect of preoperative anemia and postoperative transfusion on surgical outcomes., Results: Among 9936 included patients, complication incidence was 38.9% (sepsis 12.7%; mortality 6.0%). Preoperative Hct cut points were identified at 29 and 42. Hct <29 was associated with higher risk of morbidity (OR 2.47, 95%CI 2.10-2.93). Postoperative transfusion was associated with lower risk of morbidity for Hct <29 (OR 0.56, 95%CI 0.43-0.73) but increased risk between 29 and 42 (OR 1.59, 95%CI 1.21-2.08). Similar relationships were found for sepsis and mortality., Conclusions: Preoperative Hct <29 is associated with an increased risk of surgical complications after gastrectomy for cancer and perioperative transfusions appear to be beneficial for Hct <29 only. There may be a role for better optimization of red cell mass among high-risk patients before gastrectomy for cancer., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objectives: Organ-sparing endoscopic submucosal dissection (ESD) is an acceptable treatment strategy for superficial neoplastic lesions of the esophagus and stomach. The adoption of this technique has lagged in North America compared with Asia, and we sought to report on our experiences with ESD for upper GI neoplasia., Methods: A prospectively entered database of all patients undergoing endoscopic resection of esophageal and gastric neoplasia at McGill University from 2009 to 2019 was queried for those who received ESD., Results: A total of 103 consecutive ESDs were identified from 2009 to 2019. Seventy-one (69%) patients were male and the median age was 72 (range: 38-90). Sixty-one (59%) cases were esophageal and 42 (41%) gastric. Forty-nine (48%) were performed in the endoscopy suite under local sedation only. Perforation occurred in 9 patients (7 esophageal and 2 stomach), of which 3 required operative repair. Histology was principally invasive carcinoma (79, 77%), with 17 (16%) dysplastic lesions (e.g., HGD), 1 (1%) neuroendocrine tumor, and 7 (7%) benign lesions. En bloc resection was achieved in 90 (87%), and the complete resection rate was 74 (72%), with 51 (50%) of procedures fulfilling the criteria for curative resection. At medium of 23-month (2-199) follow-up of these 51 curative resections, one case of recurrent carcinoma was found at follow-up and was managed with repeat endoscopic resection. Non-curative ESDs were found 45 (R1 resection = 29: risk of lymph node metastasis = 16), 21 had active surveillance, and 24 were resected., Conclusion: ESD is a viable, effective, and safe therapeutic and staging modality for superficial lesions of the stomach and esophagus.

Introduction: C-reactive protein may predict anastomotic complications after colorectal surgery, but its predictive ability may differ between laparoscopic and open resection due to differences in stress response. Therefore, the objective of this study was to perform a systematic review and meta-analysis on the diagnostic characteristics of C-reactive protein to detect anastomotic leaks and infectious complications after laparoscopic and open colorectal surgery., Methods: A systematic review was performed according to PRISMA. Studies were included if they reported on the diagnostic characteristics of postoperative day 3-5 values of serum C-reactive protein to diagnose anastomotic leak or infectious complications specifically in patients undergoing elective laparoscopic and open colorectal surgery. The main outcome was a composite of anastomotic leak and infectious complications. A random-effects model was used to perform a meta-analysis of diagnostic accuracy., Results: A total of 13 studies were included (9 for laparoscopic surgery, 8 for open surgery). The pooled incidence of the composite outcome was 14.8% (95% CI 10.2-19.3) in laparoscopic studies and 21.0% (95% CI 11.9-30.0) for open. The pooled diagnostic accuracy characteristics were similar for open and laparoscopic studies. However, the C-reactive protein threshold cutoffs were lower in laparoscopic studies for postoperative days 3 and 4, but similar on day 5., Conclusions: The diagnostic characteristics of C-reactive protein in the early postoperative period to detect infectious complications and leaks are similar after laparoscopic and open colorectal surgery. However, thresholds are lower for laparoscopic surgery, suggesting that the interpretation of serum CRP values needs to be tailored based on operative approach.

Introduction: Treatment delay may have detrimental effects on cancer outcomes. The impact of longer delays on colorectal cancer outcomes remains poorly described. The objective of this study was to determine the effect of delays to curative-intent surgical resection on survival in colorectal cancer patients., Methods: All adult patients undergoing elective resection of primary non-metastatic colorectal adenocarcinoma from January 2009 to December 2014 were reviewed. Treatment delays were defined as the time from tissue diagnosis to definitive surgery, categorized as < 4, 4 to < 8, and ≥ 8 weeks. Primary outcomes were 5-year disease-free (DFS) and overall survival (OS). Statistical analysis included Kaplan-Meier curves and Cox regression models., Results: A total of 408 patients were included (83.2% colon;15.8% rectal) with a mean follow-up of 58.4 months (SD29.9). Fourteen percent (14.0%) of patients underwent resection < 4 weeks, 40.0% 4 to < 8 weeks, and 46.1% ≥ 8 weeks. More rectal cancer patients had treatment delay ≥ 8 weeks compared with colonic tumors (69.8% vs. 41.4%, p < 0.001). Cumulative 5-year DFS and OS were similar between groups (p = 0.558; p = 0.572). After adjusting for confounders, surgical delays were not independently associated with DFS and OS., Conclusions: Treatment delays > 4 weeks were not associated with worse oncologic outcomes. Delaying surgery to optimize patients can safely be considered without compromising survival.

Background: There is increasing evidence to support extended thromboprophylaxis after colorectal surgery to minimize the incidence of postdischarge venous thromboembolic events. However, the absolute number of events is small, and extended thromboprophylaxis requires significant resources from the health care system., Objective: This study aimed to determine the cost-effectiveness of extended thromboprophylaxis in patients undergoing colorectal surgery for malignancy or IBD., Design: An individualized patient microsimulation model (1,000,000 patients; 1-month cycle length) comparing extended thromboprophylaxis (28-day course of enoxaparin) to standard management (inpatient administration only) after colorectal surgery was constructed., Settings: The sources for this study were The American College of Surgeons National Surgical Quality Improvement Project Participant User File and literature searches., Outcomes: Costs (Canadian dollars), quality-adjusted life-years, and venous thromboembolism-related deaths prevented over a 1-year time horizon starting with hospital discharge were determined. The results were stratified by malignancy or IBD., Results: In patients with malignancy, extended prophylaxis was associated with higher costs (+113$; 95% CI, 102-123), but increased quality-adjusted life-years (+0.05; 95% CI, 0.04-0.06), resulting in an incremental cost-effectiveness ratio of 2473$/quality-adjusted life-year. For IBD, extended prophylaxis also had higher costs (+116$; 95% CI, 109-123), more quality-adjusted life-years (+0.05; 95% CI, 0.04-0.06), and an incremental cost-effectiveness ratio of 2475$/quality-adjusted life-year. Extended prophylaxis prevented 16 (95% CI, 4-27) venous thromboembolism-related deaths per 100,000 patients and 22 (95% CI, 6-38) for malignancy and IBD. There was a 99.7% probability of cost-effectiveness at a willingness-to-pay threshold of 50,000$/quality-adjusted life-year. To account for statistical uncertainty around variables, sensitivity analysis was performed and found that extended prophylaxis is associated with lower overall costs when the incidence of postdischarge venous thromboembolic events reaches 1.8%., Limitations: Significant differences in health care systems may affect the generalizability of our results., Conclusions: Despite the rarity of venous thromboembolic events, extended thromboprophylaxis is a cost-effective strategy. See Video Abstract at http://links.lww.com/DCR/A976. COSTO-EFECTIVIDAD DE LA TROMBOPROFILAXIS EXTENDIDA EN PACIENTES SOMETIDOS A CIRUGÍA COLORRECTAL DESDE UNA PERSPECTIVA DEL SISTEMA DE SALUD CANADIENSE:: Cada vez hay más pruebas que apoyen la tromboprofilaxis extendida después de la cirugía colorrectal para minimizar la incidencia de eventos tromboembólicos venosos después del alta hospitalaria. Sin embargo, el número absoluto de eventos es pequeño y la tromboprofilaxis extendida requiere recursos significativos del sistema médico.Determinar la rentabilidad (relación costo-efectividad) de la tromboprofilaxis extendida en pacientes sometidos a cirugía colorrectal por neoplasia maligna o enfermedad inflamatoria intestinal.Un modelo de microsimulación de paciente individualizado (1,000,000 de pacientes; ciclo de 1 mes) que compara la tromboprofilaxis extendida (curso de enoxaparina de 28 días) con el tratamiento estándar (solo para pacientes hospitalizados) después de la cirugía colorrectal.Archivo de usuario participante del Proyecto de Mejoramiento de la Calidad Quirúrgica del Colegio Nacional de Cirujanos Americanos (ACS-NSQIP) y búsquedas bibliográficas.Costos (en dólares Canadienses), años de vida ajustados por la calidad y muertes relacionadas con el tromboembolismo venoso prevenidas en un horizonte temporal de 1 año a partir del alta hospitalaria. Los resultados fueron estratificados por malignidad o enfermedad inflamatoria intestinal.En pacientes con neoplasias malignas, la profilaxis extendida se asoció con costos más altos (+113 $; IC del 95%, 102-123), pero con un aumento de la calidad de vida ajustada por años de vida (+0.05; IC del 95%, 0.04-0.06), lo que resultó en un incremento de relación costo-efectividad de 2473 $/año de vida ajustado por calidad. Para la enfermedad inflamatoria intestinal, la profilaxis extendida también tuvo costos más altos (+116 $; 95% IC, 109-123), más años de vida ajustados por calidad (+0.05; 95% IC, 0.04-0.06) y una relación costo-efectividad incremental de 2475 $/año de vida ajustado por calidad. La profilaxis prolongada evitó 16 (95% IC, 4-27) muertes relacionadas con tromboembolismo venoso por cada 100,000 pacientes y 22 (95% IC, 6-38) por malignidad y enfermedad inflamatoria intestinal, respectivamente. Hubo un 99.7% de probabilidad de costo-efectividad en un límite de disposición a pagar de 50,000 $/año de vida ajustado por calidad. Para tener en cuenta la incertidumbre estadística en torno a los variables, se realizó un análisis de sensibilidad y se encontró que la profilaxis extendida se asocia con menores costos generales cuando la incidencia de eventos tromboembólicos venosos después del alta hospitalaria alcanza 1.8%.Las diferencias significativas en los sistemas de salud pueden afectar la generalización de nuestros resultados.A pesar de la escasez de eventos tromboembólicos venosos, la tromboprofilaxis extendida es una estrategia rentable. Vea el video del resumen en http://links.lww.com/DCR/A976.

Background: Current standards for lymph node harvest in colorectal cancer surgery may be inadequate. Higher lymph node yield may improve survival, but the number of lymph nodes needed to optimize survival is unknown. The objective of this study was to examine the relationship between lymph node yield and overall survival in patients undergoing colectomy for nonmetastatic colon adenocarcinoma., Methods: The 2010 to 2014 National Cancer Database was queried for patients undergoing colectomy for nonmetastatic colon adenocarcinoma. Adjusted restricted cubic splines were used to model the nonlinear relationship between lymph node harvest and overall survival. Cox proportional hazard determined independent predictors of overall survival., Results: A total of 261,423 patients were included. Restricted cubic splines demonstrated that the adjusted improvements in overall survival stabilized after 24 nodes. Patients were divided into: <12, 12 to 23, and ≥24 nodes. On survival analysis, patients with ≥24 nodes had better survival across all N stages compared to other groups (P < .001). Lymph node harvest ≥24 nodes was independently associated with improved overall survival compared to 12 to 23 nodes (hazard ratio 0.82; 95% confidence interval, 0.80-0.85)., Conclusion: Lymph node harvest ≥24 nodes is associated with improved survival in colorectal cancer patients. These data may provide indirect evidence for a more extensive lymphadenectomy for colon cancer., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction: Several grading schemes are available to assess surgical complications, but their relationship with patient-reported outcomes is not well understood. Therefore, our objective was to examine the effect of two complication grading schemas on health-related quality of life in colorectal surgery patients., Methods: An analysis of adult patients undergoing elective colorectal surgery from 2005 to 2013 was performed. Health-related quality of life was measured using the SF-36 preoperatively and at 4 weeks and 8 weeks postoperatively. The 30-day morbidity was classified using Clavien-Dindo grading (I-IV) and the Comprehensive Complication Index (0-100). The main outcomes were the postoperative changes in physical summary scores and mental summary scores. Multivariate logistic and fractional polynomial regression analyses were used to determine the relationship between complication severity and health-related quality of life., Results: A total of 402 patients were included in the study. Overall morbidity was 46%. Patients with complications had lower physical summary scores and mental summary scores at 4-weeks and 8-weeks postoperatively compared with patients without complications (P < .05). On multivariate regression, there was no dose-response relationship between Clavien-Dindo grade and postoperative physical summary scores and mental summary scores. Adjusted changes in the physical summary scores and mental summary scores had a more appropriate, dose-response relationship with the Comprehensive Complication Index scores., Conclusion: In patients undergoing colorectal surgery, there is a more consistent relationship between the Comprehensive Complication Index and postoperative health-related quality of life compared with the Clavien-Dindo classification., (Copyright © 2019. Published by Elsevier Inc.)

Background: The management of patients with a complete clinical response after neoadjuvant therapy for rectal adenocarcinoma is controversial. Those who advocate for resection point out the inaccuracy of N-staging with current imaging modalities. The objective of this study is to determine the impact of residual nodal involvement after complete tumor regression after neoadjuvant (chemo)radiotherapy., Methods: The 2004 to 2014 National Cancer Database was queried for patients undergoing proctectomy for nonmetastatic rectal adenocarcinoma who had received neoadjuvant (chemo)radiotherapy and with ypT0 on final pathology. Patients were grouped based on pathologic nodal stage: ypT0N- and ypT0N+. The main outcome was 5-year overall survival., Results: There were 5,156 patients with ypT0N- and 527 with ypT0N+. Mean lymph node harvest was similar (ypT0N- 12.2 nodes [standard deviation 9.1] vs ypT0N+ 11.6 nodes [standard deviation 10.3]; P = .086). Patients with ypT0N+ were more likely to have had clinically involved nodes (P < .001) and earlier clinical T-stage (P = .002). Overall survival at 5 years was less for patients with ypT0N+ (80% vs 86%, log-rank P = .014). ypT0N+ was independently associated with worse overall survival (hazard ratio 1.74, 95% confidence interval 1.33-2.28)., Conclusion: Residual nodal involvement despite complete tumor regression was associated with worse 5-year overall survival compared to complete pathologic response. Additional therapy should be considered in the presence of complete clinical tumor regression after neoadjuvant (chemo)radiotherapy., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Fundoplication is performed routinely during laparoscopic repairs of a paraesophageal hernia, but the degree of fundoplication remains controversial. The purpose of this study is to assess postoperative dysphagia and reflux after a Dor versus a Nissen fundoplication in patients undergoing laparoscopic repair of giant paraesophageal hernias., Methods: We performed a retrospective cohort study of all patients undergoing laparoscopic repair of giant paraesophageal hernias with Nissen or Dor fundoplication between January 2012 and December 2017 at a high-volume center, excluding revisional and emergency cases. Primary outcomes were reflux and dysphagia at 1 and 6 months. Severe dysphagia was defined as intolerance to liquids. Balanced cohorts were created using coarsened exact matching., Results: A total of 106 patients were included, and 87 were matched (Dor = 48, Nissen = 58). Baseline characteristics were well balanced between matched groups. Mean follow-up duration was 17.7 months (standard deviation 16.4). The incidence of severe dysphagia at 1 month was less in the Dor group (0 of 48 vs 8 of 58, P = .02) with similar reflux symptoms. There was no difference in severe dysphagia and reflux symptoms at 6 months and at the latest visit., Conclusion: Dor fundoplication is associated with less severe, early postoperative dysphagia. Future studies assessing the relative importance of dysphagia and reflux on quality of life should be conducted to tailor the operative technique and optimize patient satisfaction., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Through experiments and numerical simulations we explore the behavior of rf SQUID (radio frequency superconducting quantum interference device) metamaterials, which show extreme tunability and nonlinearity. The emergent electromagnetic properties of this metamaterial are sensitive to the degree of coherent response of the driven interacting SQUIDs. Coherence suffers in the presence of disorder, which is experimentally found to be mainly due to a dc flux gradient. We demonstrate methods to recover the coherence, specifically by varying the coupling between the SQUID meta-atoms and increasing the temperature or the amplitude of the applied rf flux.