Parastomal Hernia Repair.

Parastomal hernias (PHs) are common and contribute to significant patient morbidity. Despite 45 years of evolution, mesh-based PH repairs continue to be challenging to perform and remain associated with high rates of postoperative complications and recurrences. In this article, the authors summarize the critical factors to consider when evaluating a patient for PH repair. The authors provide an overview of the current techniques for repair, including both open and minimally invasive approaches. The authors detail the mesh-based repair options and review the evidence for choice of mesh to use for repair.

Laparoscopic Common Bile Duct Exploration.

This article describes advances that are leading to a resurgence in surgeon interest and adoption of laparoscopic common bile duct exploration, making an innovation out of an old technique.

Radiologic-pathologic correlation of lesions in resected liver specimens with an ex vivo MRI-compatible localization device.

OBJECTIVE: Liver lesion characterization is limited by the lack of an established gold standard for precise correlation of radiologic characteristics with their histologic features. The objective of this study was to demonstrate the feasibility of using an ex vivo MRI-compatible sectioning device for radiologic-pathologic co-localization of lesions in resected liver specimens. METHODS: In this prospective feasibility study, adults undergoing curative partial hepatectomy from February 2018 to January 2019 were enrolled. Gadoxetic acid was administered intraoperatively prior to hepatic vascular inflow ligation. Liver specimens were stabilized in an MRI-compatible acrylic lesion localization device (27 × 14 × 14 cm3) featuring slicing channels and a silicone gel 3D matrix. High-resolution 3D T1-weighted fast spoiled gradient echo and 3D T2-weighted fast-spin-echo images were acquired using a single channel quadrature head coil. Radiologic lesion coordinates guided pathologic sectioning. A final histopathologic diagnosis was prepared for all lesions. The proportion of successfully co-localized lesions was determined. RESULTS: A total of 57 lesions were identified radiologically and sectioned in liver specimens from 10 participants with liver metastases (n = 8), primary biliary mucinous cystic neoplasm (n = 1), and hepatic adenomatosis (n = 1). Of these, 38 lesions (67%) were < 1 cm. Overall, 52/57 (91%) of radiologically identified lesions were identified pathologically using the device. Of these, 5 lesions (10%) were not initially identified on gross examination but were confirmed histologically using MRI-guided localization. One lesion was identified grossly but not on MRI. CONCLUSIONS: We successfully demonstrated the feasibility of a clinical method for image-guided co-localization and histological characterization of liver lesions using an ex vivo MRI-compatible sectioning device. KEY POINTS: • The ex vivo MRI-compatible sectioning device provides a reliable method for radiologic-pathologic correlation of small (< 1 cm) liver lesions in human liver specimens. • The sectioning method can be feasibly implemented within a clinical practice setting and used in future efforts to study liver lesion characterization. • Intraoperative administration of gadoxetic acid results in enhancement in ex vivo MRI images of liver specimens hours later with excellent image quality.

Machine learning principles applied to CT radiomics to predict mucinous pancreatic cysts.

PURPOSE: Current diagnostic and treatment modalities for pancreatic cysts (PCs) are invasive and are associated with patient morbidity. The purpose of this study is to develop and evaluate machine learning algorithms to delineate mucinous from non-mucinous PCs using non-invasive CT-based radiomics. METHODS: A retrospective, single-institution analysis of patients with non-pseudocystic PCs, contrast-enhanced computed tomography scans within 1 year of resection, and available surgical pathology were included. A quantitative imaging software platform was used to extract radiomics. An extreme gradient boosting (XGBoost) machine learning algorithm was used to create mucinous classifiers using texture features only, or radiomic/radiologic and clinical combined models. Classifiers were compared using performance scoring metrics. Shapely additive explanation (SHAP) analyses were conducted to identify variables most important in model construction. RESULTS: Overall, 99 patients and 103 PCs were included in the analyses. Eighty (78%) patients had mucinous PCs on surgical pathology. Using multiple fivefold cross validations, the texture features only and combined XGBoost mucinous classifiers demonstrated an area under the curve of 0.72 ± 0.14 and 0.73 ± 0.14, respectively. By SHAP analysis, root mean square, mean attenuation, and kurtosis were the most predictive features in the texture features only model. Root mean square, cyst location, and mean attenuation were the most predictive features in the combined model. CONCLUSION: Machine learning principles can be applied to PC texture features to create a mucinous phenotype classifier. Model performance did not improve with the combined model. However, specific radiomic, radiologic, and clinical features most predictive in our models can be identified using SHAP analysis.

Pancreatic cyst characterization: maximum axial diameter does not measure up.

BACKGROUND: Unidimensional size is commonly used to risk stratify pancreatic cysts (PCs) despite inconsistent performance. The current study aimed to determine if unidimensional size, demonstrated by maximum axial diameter (MAD), is an appropriate surrogate measurement for volume and surface area. METHODS: Patients with cross-sectional imaging of PCs from 2012 to 2013 were identified. Cyst MAD, volume, and surface area were measured using quantitative imaging software. Non-pseudocystic PCs >1 cm were selected for inclusion to assess MAD correlation with volume and surface area. Cysts imaged twice >1 year apart were selected to evaluate volumetric growth rate. RESULTS: In total, 195 cysts were included. Overall, MAD was strongly correlated with volume (r = 0.83) and surface area (r = 0.93). However, cysts 1-2 cm and 2-3 cm were weakly correlated with volume and surface area: r = 0.78, 0.57 and 0.82, 0.61, respectively. Cyst volumes and surface areas varied widely within unidimensional size groups with 51% and 40% of volumes and surface areas overlapping unidimensional size groups, respectively. Estimated changes in volume poorly predicted measured changes in volume with 42% of cysts having >100% absolute percent difference. CONCLUSIONS: Pancreatic cyst volume and surface area may be useful adjunct measurements to risk stratify patients and surveil cyst changes and deserves further study.

Resident Perspectives on Effective Surgical Training: Incivility, Confidence, and Mindset.

OBJECTIVE: Ample evidence exists that one's internal state (e.g., mindset, emotion) impacts one's performance. Both the military and sports organizations have focused on optimizing internal states of their service members and athletes, respectively, to improve performance and wellbeing. The internal states of surgical residents and the factors that influence their internal states have not yet been examined. Our goal is to better understand whether certain internal states are beneficial for resident operative performance, and how to optimize these during surgical training. DESIGN: A 17-question survey, containing both open-ended and multiple-choice questions, was distributed to all (n = 134) surgical residents at the University of Wisconsin. In open-ended questions, recurring themes were identified utilizing content analysis. Recurring themes stated by 25% or more of the respondents are reported. SETTING: Department of Surgery at the University of Wisconsin-Madison. PARTICIPANTS: Surgical residents at the University of Wisconsin. RESULTS: The survey response rate varied between n = 47 (35%) and n = 32 (24%), as not all respondents answered all questions. (1) Effective surgical educators were identified to demonstrate humanism and focus on teaching. (2) Nearly all residents affirmed that certain mindsets help them excel in the OR, including positive and confident mindsets. (3) Nearly all residents affirmed that faculty and senior residents influence their mindsets. (4) Constructive resident mindsets were promoted by positive faculty behaviors and personal preparation, while negative faculty behaviors were identified to stifle constructive mindsets. (5) Factors contributing to favorable OR performance included personal preparation and positive OR environments. (6) Factors contributing to poor OR performance included inadequate preparation and negative interactions with faculty. CONCLUSIONS: Residents near unanimously believe that certain mindsets help them excel, and that faculty impact their mindsets. As teachers, we must strive to better understand how to foster constructive mindsets in residents to optimize learning, performance, and wellbeing.

Medawar's Paradox and Immune Mechanisms of Fetomaternal Tolerance.

Brazilian-born British biologist Dr. Peter Medawar played an integral role in developing the concepts of immunologic rejection and tolerance, which led to him receiving the Nobel Prize "for the discovery of acquired immunologic tolerance" and eventually made organ transplantation a reality. However, at the time of his early work in tolerance, a paradox to his theories was brought to his attention; how was pregnancy possible? Pregnancy resembles organ transplantation in that the fetus, possessing paternal antigens, is a semi-allogeneic graft that can survive without immunosuppression for 9 months. To answer this question, Medawar proposed three hypotheses of how a mother supports her fetus in utero, now known as "Medawar's Paradox." The mechanisms that govern fetomaternal tolerance are still incompletely understood but may provide critical insight into how to achieve immune tolerance in organ transplantation. Here, we review current understanding of the immune factors responsible for fetomaternal tolerance during pregnancy and discuss the potential implications for advances in transplantation science.

Specific Growth Rate as a Predictor of Survival in Pancreatic Neuroendocrine Tumors: A Multi-institutional Study from the United States Neuroendocrine Study Group.

BACKGROUND: Pancreatic neuroendocrine tumors (PNETs) are often indolent; however, identifying patients at risk for rapidly progressing variants is critical, particularly for those with small tumors who may be candidates for expectant management. Specific growth rate (SGR) has been predictive of survival in other malignancies but has not been examined in PNETs. METHODS: A retrospective cohort study of adult patients who underwent PNET resection from 2000 to 2016 was performed utilizing the multi-institutional United States Neuroendocrine Study Group database. Patients with ≥ 2 preoperative cross-sectional imaging studies at least 30 days apart were included in our analysis (N = 288). Patients were grouped as "high SGR" or "low SGR." Demographic and clinical factors were compared between the groups. Kaplan-Meier and log-rank analysis were used for survival analysis. Cox proportional hazard analysis was used to assess the impact of various clinical factors on overall survival (OS). RESULTS: High SGR was associated with higher T stage at resection, shorter doubling time, and elevated HbA1c (all P ≤ 0.01). Patients with high SGR had significantly decreased 5-year OS (63 vs 80%, P = 0.01) and disease-specific survival (72 vs 91%, P = 0.03) compared to those with low SGR. In patients with small (≤ 2 cm) tumors (N = 106), high SGR predicted lower 5-year OS (79 vs 96%, P = 0.01). On multivariate analysis, high SGR was independently associated with worse OS (hazard ratio 2.67, 95% confidence interval 1.05-6.84, P = 0.04). CONCLUSION: High SGR is associated with worse survival in PNET patients. Evaluating PNET SGR may enhance clinical decision-making, particularly when weighing expectant management versus surgery in patients with small tumors.

Texture Analysis: An Emerging Clinical Tool for Pancreatic Lesions.

Radiologic characterization of pancreatic lesions is currently limited. Computed tomography is insensitive in detecting and characterizing small pancreatic lesions. Moreover, heterogeneity of many pancreatic lesions makes determination of malignancy challenging. As a result, invasive diagnostic testing is frequently used to characterize pancreatic lesions but often yields indeterminate results. Computed tomography texture analysis (CTTA) is an emerging noninvasive computational tool that quantifies gray-scale pixels/voxels and their spatial relationships within a region of interest. In nonpancreatic lesions, CTTA has shown promise in diagnosis, lesion characterization, and risk stratification, and more recently, pancreatic applications of CTTA have been explored. This review outlines the emerging role of CTTA in identifying, characterizing, and risk stratifying pancreatic lesions. Although recent studies show the clinical potential of CTTA of the pancreas, a clear understanding of which specific texture features correlate with high-grade dysplasia and predict survival has not yet been achieved. Further multidisciplinary investigations using strong radiologic-pathologic correlation are needed to establish a role for this noninvasive diagnostic tool.

Adjuvant therapy following resection of gastroenteropancreatic neuroendocrine tumors provides no recurrence or survival benefit.

BACKGROUND AND OBJECTIVES: Lack of high-level evidence supporting adjuvant therapy for patients with resected gastroenteropancreatic neuroendocrine tumors (GEP NETs) warrants an evaluation of its non-standard of care use. METHODS: Patients with primary GEP NETs who underwent curative-intent resection at eight institutions between 2000 and 2016 were identified; 91 patients received adjuvant therapy. Recurrence-free survival (RFS) and overall survival (OS) were compared between adjuvant cytotoxic chemotherapy and somatostatin analog cohorts. RESULTS: In resected patients, 33 received cytotoxic chemotherapy, and 58 received somatostatin analogs. Five-year RFS/OS was 49% and 83%, respectively. Cytotoxic chemotherapy RFS/OS was 36% and 61%, respectively, lower than the no therapy cohort (P < .01). RFS with somatostatin analog therapy (compared to none) was lower (P < .01), as was OS (P = .01). On multivariable analysis, adjuvant cytotoxic therapy was negatively associated with RFS but not OS controlling for patient/tumor-specific characteristics (RFS P < .01). CONCLUSIONS: Our data, reflecting the largest reported experience to date, demonstrate that adjuvant therapy for resected GEP NETs is negatively associated with RFS and confers no OS benefit. Selection bias enriching our treatment cohort for individuals with unmeasured high-risk characteristics likely explains some of these results; future studies should focus on patient subsets who may benefit from adjuvant therapy.

Impact of Insurance Status on Survival in Gastroenteropancreatic Neuroendocrine Tumors.

BACKGROUND: Insurance status predicts access to medical care in the USA. Previous studies have shown uninsured patients with some malignancies have worse outcomes than insured patients. The impact of insurance status on patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) is unclear. PATIENTS AND METHODS: A retrospective cohort study of adult patients with resected GEP-NETs was performed using the US Neuroendocrine Tumor Study Group (USNETSG) database (2000-2016). Demographic and clinical factors were compared by insurance status. Patients ≥ 65 years were excluded, as these patients are almost universally covered by Medicare. Kaplan-Meier and log-rank analyses were used for survival analysis. Logistic regression was used to assess factors associated with overall survival (OS). RESULTS: The USNETSG database included 2022 patients. Of those, 1425 were aged 18-64 years at index operation and were included in our analysis. Uninsured patients were more likely to have an emergent operation (7.9% versus 2.5%, p = 0.01) and less likely to receive postoperative somatostatin analog therapy (1.6% versus 9.9%, p = 0.03). OS at 1, 5, and 10 years was significantly higher for insured patients (96.3%, 88.2%, and 73.8%, respectively) than uninsured patients (87.7%, 71.9%, and 44.0%, respectively) (p < 0.01). On Cox multivariate regression analysis controlling for T/M stage, tumor grade, ASA class, and income level, being uninsured was independently associated with worse OS [hazard ratio (HR) 2.69, 95% confidence interval (CI) 1.32-5.48, p = 0.006]. CONCLUSIONS: Insurance status is an independent predictor of survival in patients with GEP-NETs. Our study highlights the importance of access to medical care, disparities related to insurance status, and the need to mitigate these disparities.

Severity of Postoperative Complications From the Perspective of the Patient.

BACKGROUND: Although provider-derived surgical complication severity grading systems exist, little is known about the patient perspective. OBJECTIVE: To assess patient-rated complication severity and determine concordance with existing grading systems. METHODS: A survey asked general surgery patients to rate the severity of 21 hypothetical postoperative events representing grades 1 to 5 complications from the Accordion Severity Grading System. Concordance with the Accordion scale was examined. Separately, descriptive ratings of 18 brief postoperative events were ranked. RESULTS: One hundred sixty-eight patients returned a mailed survey following their discharge from a general surgery service. Patients rated grade 4 complications highest. Grade 1 complications were rated similarly to grade 5 and higher than grades 2 and 3 (P ≤ .01). Patients rated one event not considered an Accordion scale complication higher than all but grade 4 complications (P < .001). The brief events also did not follow the Accordion scale, other than the grade 6 complication ranking highest. CONCLUSION: Patient-rated complication severity is discordant with provider-derived grading systems, suggesting the need to explore important differences between patient and provider perspectives.

Impact of perioperative blood transfusion on survival in pancreatic neuroendocrine tumor patients: analysis from the US Neuroendocrine Study Group.

BACKGROUND: Packed red blood cell (PRBC) transfusion has been associated with worse survival in multiple malignancies but its impact on pancreatic neuroendocrine tumors (PNETs) is unknown. The aim of this study was to determine the impact of PRBC transfusion on survival following PNET resection. METHODS: A retrospective cohort study of PNET patients was performed using the US Neuroendocrine Tumor Study Group database. Demographic and clinical factors were compared. Kaplan-Meier and log-rank analyses were performed. Factors associated with transfusion, overall (OS), recurrence-free (RFS) and progression-free survival (PFS) were assessed by logistic regression. RESULTS: Of 1129 patients with surgically resected PNETs, 156 (13.8%) received perioperative PRBC transfusion. Transfused patients had higher ASA Class, lower preoperative hemoglobin, larger tumors, more nodal involvement, and increased major complications (all p < 0.010). Transfused patients had worse median OS (116 vs 150 months, p < 0.001), worse RFS (83 vs 128 months, p < 0.01) in curatively resected (n = 1047), and worse PFS (11 vs 24 months, p = 0.110) in non-curatively resected (n = 82) patients. On multivariable analysis, transfusion was associated with worse OS (HR 1.80, p = 0.011) when controlling for TNM stage, tumor grade, final resection status, and pre-operative anemia. CONCLUSION: PRBC transfusion is associated with worse survival for patients undergoing PNET resection.

Evaluating the ACS NSQIP Risk Calculator in Primary Pancreatic Neuroendocrine Tumor: Results from the US Neuroendocrine Tumor Study Group.

BACKGROUND: In a changing health care environment where patient outcomes will be more closely scrutinized, the ability to predict surgical complications is becoming increasingly important. The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) online risk calculator is a popular tool to predict surgical risk. This paper aims to assess the applicability of the ACS NSQIP calculator to patients undergoing surgery for pancreatic neuroendocrine tumors (PNETs). METHODS: Using the US Neuroendocrine Tumor Study Group (USNET-SG), 890 patients who underwent pancreatic procedures between 1/1/2000-12/31/2016 were evaluated. Predicted and actual outcomes were compared using C-statistics and Brier scores. RESULTS: The most commonly performed procedure was distal pancreatectomy, followed by standard and pylorus-preserving pancreaticoduodenectomy. For the entire group of patients studied, C-statistics were highest for discharge destination (0.79) and cardiac complications (0.71), and less than 0.7 for all other complications. The Brier scores for surgical site infection (0.1441) and discharge to nursing/rehabilitation facility (0.0279) were below the Brier score cut-off, while the rest were equal to or above and therefore not useful for interpretation. CONCLUSION: This work indicates that the ACS NSQIP risk calculator is a valuable tool that should be used with caution and in coordination with clinical assessment for PNET clinical decision-making.

Analysis of National Presentations of Surgical Case Series Discussions: What Matters to Surgeons?

BACKGROUND: Although the surgical case series is a useful study design for surgical disciplines, elements of its presentation have not been standardized with a widely accepted reporting guideline. Hence, case series may not include all components necessary for surgeons to best interpret their results. We aimed to determine core elements of case series through qualitative analysis of discussions after presentations at national meetings. METHODS: Case series with accompanying discussions in three high-impact journals from 2010 to 2015 were analyzed with conventional content analysis. All interrogative sentences were selected for analysis and were classified by a redundant iterative process into descriptive categories and subcategories. RESULTS: Two hundred twenty-one case series were identified, 56 of which included discussion transcripts. Four hundred seventy six unique interrogatives were classified into 4 categories and 13 subcategories. The main categories identified were "Application of Results to Patient Care," "Clarification of Study Methodology," "Facilitation of Author Insight," and "Request for Additional Study-Specific Data." The most frequent subcategories of inquiry pertained to the changes to current standard of care, clarification of study variables, and subgroup data and outcomes. CONCLUSIONS: We determined major themes of inquiry that reflected core elements surgeons use to evaluate case series for relevance and applicability to their own practice. Discussants frequently questioned how the study's results changed the author's standard of care. Specifically encouraging surgical case series authors to comment on changes they made to their practice as a result of their findings would allow the surgical audience to quickly assess potential clinical applicability.

Predictive Value of Chromogranin A and a Pre-Operative Risk Score to Predict Recurrence After Resection of Pancreatic Neuroendocrine Tumors.

INTRO: Chromogranin A (CgA) may be prognostic for patients with neuroendocrine tumors; however, the clinical utility of this test is unclear. METHODS: Patients undergoing resection for pancreatic neuroendocrine tumors (pNET) were selected from the eight institutions of the US Neuroendocrine Tumor Study Group database. Cox regression was used to identify pre-operative variables that predicted recurrence-free survival (RFS), and those with p < 0.1 were included in a risk score. The risk score was tested in a unique subset of the overall cohort. RESULTS: In the entire cohort of 287 patients, median follow-up time was 37 months, and 5-year RFS was 73%. Cox regression analysis identified four variables for inclusion in the risk score: CgA > 5x ULN (HR 4.3, p = 0.01), tumor grade 2/3 (HR 3.7, p = 0.01), resection for recurrent disease (HR 6.2, p < 0.01), and tumor size > 4 cm (HR 4.5, p = 0.1). Each variable was assigned 1 point. Risk-score testing in the unique validation cohort of 63 patients revealed a 95% negative predictive value for recurrence in patients with zero points. DISCUSSION: This simple pre-operative risk scoring system resulted in a high degree of specificity for identifying patients at low-risk for tumor recurrence. This test can be utilized pre-operatively to aid informed decision-making.

Survey of Surgeons' Perspectives of Wound Care Centers and Chronic Wound Care.

Multidisciplinary management of chronic wounds using comprehensive wound centers improves outcomes. With an increasing need for wound providers, little is known about surgeons' roles in wound centers. An online survey of two national surgical organization members covered demographics, wound center characterization, and surgeons' perspectives of wound centers and wound care. Surgeon perspectives were compared by age, gender, and relationship status. Three hundred sixty-four surgeons responded. Respondents were mostly older than 50 years, male, in practice older than 10 years, and used wound centers. Most respondents reported favorable experiences with wound centers but uncertainty about financial details. Most respondents were interested in formal wound care certification and participation in a wound practice, particularly as a transition to the retirement option for older surgeons. Surgeons are interested in pursuing a career focus in wound care. Further efforts are needed to educate surgeons and create a pathway for surgeons to become wound center directors. In a nationwide survey, surgeon perspectives on wound centers and wound specialization were positive, although financial understanding was limited. The importance of this finding is the support of wound care pathways for surgeons.

Expanding the Scope of Evidence-Based Cancer Care.

This article explores how oncology research can be expanded to ensure that research spending results in maximum benefit. The focus has shifted to the value and quality of care, which view cancer care with the perspective of the patient at the center and cover the spectrum of care. Because there is no agreed-upon definition for value in cancer care, we overview various contributions to defining value and quality in oncology. We outline how cancer care costs are measured in the United States and explore outcome measures that have been proposed and implemented to enable us to assess value in oncology.