The Decline of Small Practice in Colorectal Surgery: Practice Consolidation From 2015-2022.

INTRODUCTION: Physicians have gravitated toward larger group practice arrangements in recent years. However, consolidation trends in colorectal surgery have yet to be well described. Our objective was to assess current trends in practice consolidation within colorectal surgery and evaluate underlying demographic trends including age, gender, and geography. METHODS: We performed a retrospective cross-sectional study using the Center for Medicare Services National Downloadable File from 2015 to 2022. Colorectal surgeons were categorized by practice size and by region, gender, and age. RESULTS: From 2015 to 2022, the number of colorectal surgeons in the United States increased from 1369 to 1621 (+18.4%), while the practices with which they were affiliated remained relatively stable (693-721, +4.0%). The proportion of colorectal surgeons in groups of 1-2 members fell from 18.9% to 10.7%. Conversely, those in groups of 500+ members grew from 26.5% to 45.2% (linear trend P < 0.001). The midwest region demonstrated the highest degree of consolidation. Affiliations with group practices of 500+ members saw large increases from both female and male surgeons (+148.9% and +86.9%, respectively). New surgeons joining the field since 2015 overwhelmingly practice in larger groups (5.3% in groups of 1-2, 50.1% in groups of 500+). CONCLUSIONS: Colorectal surgeons are shifting toward larger practice affiliations. Although this change is happening across all demographic groups, it appears unevenly distributed across geography, gender, and age. New surgeons are preferentially joining large group practices.

Medicare Reimbursement in Colorectal Surgery: A Growing Problem.

BACKGROUND: Medicare reimbursement rates have decreased across various specialties but have not yet been studied in colorectal surgery. OBJECTIVE: This study aimed to analyze Medicare reimbursement trends in colorectal surgery. DESIGN: Observational study. SETTING: The Centers for Medicare and Medicaid Services' Physician Fee Schedule was evaluated for reimbursement data for the 20 most common colorectal surgery procedures from 2006 to 2020. MAIN OUTCOME MEASURES: Inflation-adjusted annual percentage change, compound annual growth rate, and total percentage change were the outcome measures. A subanalysis was performed comparing the changes in reimbursement between 2006 to 2016 and 2016 to 2020 because of legislative changes that went into effect in 2016. RESULTS: During the study period, the inflation-unadjusted mean Medicare reimbursement rate for the 20 most common colorectal surgery procedures increased by +15.6%. This rise was surpassed by the inflation rate of +31.3%. Consequently, the inflation-adjusted reimbursement rate decreased by -11%. The adjusted reimbursement rates decreased the most at -33.8% for a flexible colonoscopy with biopsy and increased the most at +45.3% for a diagnostic rigid proctosigmoidoscopy. Annual percentage change was -0.79%, and the compound annual growth rate was -0.98%. There was an accelerated decrease in annual reimbursement rates from 2016 to 2020 at -2.23% compared to 2006 to 2016 at -0.22% ( p = 0.03). The only procedure that had an increase in adjusted reimbursement rate from 2016 to 2020 was the injection of sclerosing solution for hemorrhoids. LIMITATIONS: Only Medicare reimbursement data were analyzed. CONCLUSIONS: Medicare reimbursements for colorectal surgery procedures are decreasing at an accelerating rate. Although this study is limited to Medicare data, it still presents a representation of overall reimbursement changes because Medicare policies have a ripple effect in the commercial insurance market. It is vital to understand the financial trends to be able to structure future patient care teams and to advocate for the sustainability of colorectal surgery practices in the United States. See Video Abstract at http://links.lww.com/DCR/C136 . REEMBOLSO DE MEDICARE EN CIRUGA COLORRECTAL UN PROBLEMA CRECIENTE: ANTECEDENTES: Las tasas de reembolso de Medicare han disminuido en varias especialidades, pero aún no han sido estudiado en cirugía colorrectal.OBJETIVO: Analizar las tendencias de reembolso de Medicare en cirugía colorrectal.DISEÑO: Estudio observacional.CONTEXTO: Se evaluó el programa de tarifas médicas de los Centros de Servicios de Medicare y Medicaid para obtener datos de reembolso de los 20 procedimientos más comunes en cirugía colorrectal entre los años 2006 y 2020.PRINCIPALES MEDIDAS DE RESULTADO: Variación porcentual anual ajustada por inflación, tasa de crecimiento anual compuesta y variación porcentual total. Se realizó un subanálisis comparando los cambios en el reembolso entre los años 2006 a 2016 y 2016 a 2020 debido a los cambios legislativos que entraron en vigencia en 2016.RESULTADOS: Durante el período de estudio, la tasa media de reembolso de Medicare sin ajuste por inflación para los 20 procedimientos más comunes en cirugía colorrectal aumentó en +15,6 %. Esta suba fue superada por la tasa de inflación del +31,3%. En consecuencia, la tasa de reembolso ajustada por inflación disminuyó un -11%. Lo máximo que disminuyeron las tasas ajustadas de reembolso fue a -33,8% para una colonoscopia flexible con biopsia y aumentaron más a +45,3% para una proctosigmoidoscopia rígida de diagnóstico. El cambio porcentual anual fue -0,79% y la tasa de crecimiento anual compuesto fue -0,98%. Hubo una disminución acelerada en las tasas de reembolso anual de 2016 a 2020 a -2,23 % en comparación con 2006 a 2016 a -0,22% ( p = 0,03). El único procedimiento que tuvo un aumento en la tasa de reembolso ajustada de 2016 a 2020 fue la inyección de solución esclerosante para las hemorroides.LIMITACIONES: Solo se analizaron los datos de reembolso de Medicare.CONCLUSIONES: Los reembolsos de Medicare por procedimientos en cirugía colorrectal están disminuyendo a un ritmo acelerado. Aunque este estudio se limita a los datos de Medicare, aún presenta una representación de los cambios generales en los reembolsos, ya que las pólizas de Medicare tienen un efecto dominó en el mercado de seguros comerciales. Es fundamental comprender las tendencias financieras para poder estructurar futuros equipos de atención de pacientes y abogar por la sostenibilidad de las prácticas de cirugía colorrectal en los Estados Unidos. Consulte Video Resumen video en https://links.lww.com/DCR/C136 . (Traducción-Dr. Osvaldo Gauto ).

Clostridium difficile infection in the USA: incidence and associated factors in revision total knee arthroplasty patients.

INTRODUCTION: Revision total knee arthroplasty (TKA) procedures performed secondary to periprosthetic joint infection (PJI) are associated with significant morbidity and mortality. These poor outcomes may be further complicated by postoperative infection requiring antibiotics. However, antibiotic overuse may suppress patients' bacterial flora, leading to Clostridium difficile infection (CDI). Therefore, we aimed to study the: (1) incidence; (2) costs; and (3) risk factors associated with CDI in revision TKA patients. METHODS: The National Inpatient Sample database was queried for individuals diagnosed with PJI who underwent revision TKA between 2009 and 2013 (n = 83,806). Patients who developed CDI during their inpatient stay were identified (n = 799). Logistic regression analysis was conducted to assess the association between hospital- and patient-specific characteristics and the development of CDI. RESULTS: The incidence of CDI after revision TKA was 1.0%. These patients were older (mean age 69.05 vs. 65.52 years), had greater LOS (median 11 vs. 5 days) and greater costs ($30,612.93 vs. 18,873.75), and experienced higher in-hospital mortality (3.6 vs. 0.5%; p < 0.001 for all) compared to those without infection. Patients with CDI were more likely to be treated in urban, not-for-profit, medium/large hospitals in the Northeast or Midwest (p < 0.05 for all) and to have underlying depression (OR 4.267; p = 0.007) or fluid/electrolyte disorders (OR 3.48; p = 0.001). CONCLUSION: Although CDI is rare following revision TKA, it can have detrimental consequences. We demonstrate that CDI is associated with longer LOS, higher costs, and greater in-hospital mortality. With increased legislative pressure to lower healthcare expenditures, it is crucial to identify means of preventing costly complications.

Experimental Observation of Hidden Berry Curvature in Inversion-Symmetric Bulk 2H-WSe_{2}.

We investigate the hidden Berry curvature in bulk 2H-WSe_{2} by utilizing the surface sensitivity of angle resolved photoemission (ARPES). The symmetry in the electronic structure of transition metal dichalcogenides is used to uniquely determine the local orbital angular momentum (OAM) contribution to the circular dichroism (CD) in ARPES. The extracted CD signals for the K and K^{'} valleys are almost identical, but their signs, which should be determined by the valley index, are opposite. In addition, the sign is found to be the same for the two spin-split bands, indicating that it is independent of spin state. These observed CD behaviors are what are expected from Berry curvature of a monolayer of WSe_{2}. In order to see if CD-ARPES is indeed representative of hidden Berry curvature within a layer, we use tight binding analysis as well as density functional calculation to calculate the Berry curvature and local OAM of a monolayer WSe_{2}. We find that measured CD-ARPES is approximately proportional to the calculated Berry curvature as well as local OAM, further supporting our interpretation.

Electron Number-Based Phase Diagram of Pr_{1-x}LaCe_{x}CuO_{4-δ} and Possible Absence of Disparity between Electron- and Hole-Doped Cuprate Phase Diagrams.

We performed annealing and angle resolved photoemission spectroscopy studies on electron-doped cuprate Pr_{1-x}LaCe_{x}CuO_{4-δ} (PLCCO). It is found that the optimal annealing condition is dependent on the Ce content x. The electron number (n) is estimated from the experimentally obtained Fermi surface volume for x=0.10, 0.15 and 0.18 samples. It clearly shows a significant and annealing dependent deviation from the nominal x. In addition, we observe that the pseudo-gap at hot spots is also closely correlated with n; the pseudogap gradually closes as n increases. We established a new phase diagram of PLCCO as a function of n. Different from the x-based one, the new phase diagram shows similar antiferromagnetic and superconducting phases to those of hole doped ones. Our results raise a possibility for absence of disparity between the phase diagrams of electron- and hole-doped cuprates.

Excimers beyond pyrene: a far-red optical proximity reporter and its application to the label-free detection of DNA.

A family of organic chromophores that, like pyrene, forms emissive excimers is reported. Their chemical and photophysical properties are superior to pyrene for the design of chemo- and biosensors. Unlike hydrophobic pyrene, which requires excitation by cell-damaging UV irradiation, these polar dyes absorb strongly in the visible range, and their excimers emit brightly in the red to far-red region of the electromagnetic spectrum. The intensity of the emission signal is greatly increased upon formation of a preassociated dimer that is triggered upon aggregation or crystallization. In demonstration of the potential of this new family of excimer-forming dyes, a probe that is capable of detecting label-free DNA in water down to 10 pM and also doubles as a visualization agent for DNA in gel electrophoresis is reported.

Versatile Mechanically Tunable Hydrogels for Therapeutic Delivery Applications.

Hydrogels provide a versatile platform for biomedical material fabrication that can be structurally and mechanically fine-tuned to various tissues and applications. Applications of hydrogels in biomedicine range from highly dynamic injectable hydrogels that can flow through syringe needles and maintain or recover their structure after extrusion to solid-like wound-healing patches that need to be stretchable while providing a selective physical barrier. In this study, a toolbox is designed using thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) polymeric matrices and nanocelluloses as reinforcing agent to obtain biocompatible hydrogels with altering mechanical properties, from a liquid injectable to a solid-like elastic hydrogel. The liquid hydrogels possess low viscosity and shear-thinning properties at 25 °C, which allows facile injection at room temperature, while they become viscoelastic gels at body temperature. In contrast, the covalently cross-linked solid-like hydrogels exhibit enhanced viscoelasticity. The liquid hydrogels are biocompatible and are able to delay the in vitro release and maintain the bioactivity of model drugs. The antimicrobial agent loaded solid-like hydrogels are effective against typical wound-associated pathogens. This work presents a simple method of tuning hydrogel mechanical strength to easily adapt to applications in different soft tissues and broaden the potential of renewable bio-nanoparticles in hybrid biomaterials with controlled drug release capabilities.

Traumatic Anterior Tibial Artery Pseudoaneurysm: A Case Report.

Introduction: Traumatic pseudoaneurysms of the limbs are rare, with few cases described in vascular literature. Treatment is variable and dependent upon presentation and impact on local anatomy affected. Rapid assessment can be performed with ultrasound and assist in treatment decisions. We describe a case of traumatic anterior tibial artery pseudoaneurysm, which was rapidly identified with point-of-care ultrasound leading to definitive surgical management. Case Report: A 37-year-old female presented to the emergency department for evaluation of right lower extremity pain and swelling following an exercise session with weighted squats and thigh abductor machines. She was found to have an anterior tibial artery pseudoaneurysm on point-of-care ultrasound, later confirmed with formal ultrasound as well as angiography, and was admitted for surgical management. Conclusion: Traumatic pseudoaneurysms can rapidly be differentiated from other mass lesions and contributors to compartment syndrome using point-of-care ultrasound.

Outcomes of a Large Series of Laparoscopic Ventral Hernia Repairs after Liver Transplantation.

BACKGROUND: The hernia defects that develop in liver transplant recipients tend to be complex. Unfortunately, there is a paucity of data to guide post-transplant hernia management. Our goal was to evaluate the outcomes following laparoscopic ventral hernia repair (LVHR) in liver transplant recipients. METHODS: A retrospective review of a prospectively kept database of liver transplant patients at a single tertiary healthcare facility was completed. All patients between 2007 and 2020 who underwent LVHR for a hernia at their transplant incision site were included. The primary outcome studied was hernia recurrence. Secondary outcomes included time-to-hernia repair, complications, and length of stay (LOS). RESULTS: There were 89 patients who met inclusion criteria. 82% were male, mean age was 60 years, and mean body mass index was 30.2 kg/m2. 94.4% were on tacrolimus and 36% on mycophenolate mofetil. Median time-to-hernia repair was 16 months with a mean mesh size of 743 cm2 and length of stay of 3.7 days. None required conversion to an open operation. Postoperative complications included ileus (20.2%), acute kidney injury (11.2%), pneumonia (6.7%), and bleeding requiring re-operation (1.1%). Hernia-related complications included chronic suture site pain (1.1%), seroma requiring intervention (3.3%), surgical site infection (3.3%), nonoperative mesh infection (1.1%), and mesh infection requiring explantation (1.1%). Median follow-up was 23 months. Hernia recurrence occurred in 4.5% and no predictive variables for recurrence were identified. CONCLUSIONS: Although the hernia defects that develop in liver transplant recipients are complex and their comorbidities significant, LVHR can safely and effectively repair these defects with low rates of recurrence and complications.

Short and long-term oncologic outcomes of patients with colon cancer of the splenic flexure.

BACKGROUND: There is currently no consensus on surgical management of splenic flexure adenocarcinoma (SFA). METHODS: Patients undergoing surgical resection for SFA between 1993 and 2015 were identified. Postoperative outcomes were compared between patients who underwent segmental (SR) vs. anatomical resection (AR). RESULTS: One-hundred and thirteen patients underwent SR and 89 underwent AR. More patients in the SR group had open resections, but there were otherwise no differences in demographics or surgical characteristics between the two groups. There were no differences in overall (p = 0.29) or recurrence-free(p = 0.37) survival. On multivariable analysis, increased age (HR 1.04, 1.01-1.07, p = 0.005), higher American Society of Anesthesiology classification (HR 3.1, 1.7-5.71, p < 0.001), and higher tumor stage (HR 8.84, 3.76-20.82, p < 0.001) were predictive of mortality. CONCLUSIONS: Short and long-term outcomes after SR and AR for SFA are not different, making SR a viable option for SFA surgical management.

Tracheostomy in high-risk patients on ECMO: A bedside hybrid dilational technique utilizing a Rummel tourniquet.

Objective: Traditionally, critically ill patients requiring prolonged mechanical ventilation benefit from a long-term airway, thus necessitating tracheostomy. The widespread application of extracorporeal membrane oxygenation (ECMO) has exponentially increased in recent years, creating a new subset of patients necessitating tracheostomy with significantly increased bleeding risk. We present a hybrid dilational tracheostomy technique utilizing a Rummel tourniquet developed at our institution to mitigate bleeding risk in patients on ECMO necessitating long-term airway. Methods: A total of 24 patients on ECMO underwent bedside hybrid dilational tracheostomy with utilization of a Rummel tourniquet from 06/2020 to 01/2022 at our institution. These patients were followed longitudinally and evaluated for postoperative bleeding. Particular attention was paid to anticoagulation regimens pre- and post-operatively. Results: The primary outcome of the study, postoperative bleeding, was observed in four of the 24 study participants (16.67 %). Each of these complications were managed with tightening of the Rummel tourniquet and application of hemostatic packing agents; no operative interventions were required. Anticoagulation was held for a mean time of 4.33 h preoperatively and 5.2 h postoperatively. Conclusions: Our data support this hybrid tracheostomy technique with the addition of a Rummel tourniquet to be a safe and effective adjunct for perioperative hemostasis in high-risk patients necessitating tracheostomy while on ECMO. While this technique was initially developed for critically ill COVID-19 patients, we believe it can be applied to all patients on ECMO to help mitigate perioperative bleeding risk.

Capturing the often-elusive diagnosis of idiopathic myointimal hyperplasia of mesenteric veins.

Only 50 cases of idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) have been reported since 1991 when it was first described. This rare etiology for chronic colonic ischemia is often debilitating to the patient's quality of life, and no effective medical treatment is available. IMHMV is frequently confused with inflammatory bowel disease because the most common presenting symptoms include abdominal pain, diarrhea, and hematochezia. Surgical resection is curative; however, the diagnosis is rarely reached preoperatively. In the present report, we have described the seventh patient with a diagnosis of IMHMV before surgery and included a literature review to help clinicians recognize this condition.

Direct observation of kink evolution due to Hund's coupling on approach to metal-insulator transition in NiS2-xSex.

Understanding characteristic energy scales is a fundamentally important issue in the study of strongly correlated systems. In multiband systems, an energy scale is affected not only by the effective Coulomb interaction but also by the Hund's coupling. Direct observation of such energy scale has been elusive so far in spite of extensive studies. Here, we report the observation of a kink structure in the low energy dispersion of NiS2-xSex and its characteristic evolution with x, by using angle resolved photoemission spectroscopy. Dynamical mean field theory calculation combined with density functional theory confirms that this kink originates from Hund's coupling. We find that the abrupt deviation from the Fermi liquid behavior in the electron self-energy results in the kink feature at low energy scale and that the kink is directly related to the coherence-incoherence crossover temperature scale. Our results mark the direct observation of the evolution of the characteristic temperature scale via kink features in the spectral function, which is the hallmark of Hund's physics in the multiorbital system.

Exploring the Effect of Post-mastectomy complications on 5-year survival.

BACKGROUND: Ramifications of postoperative complications on long-term survival after mastectomy are uncertain. METHODS: Overall complications (Clavien-Dindo Grades I-IIIB) and wound complications were analyzed using the Kaplan-Meier method for impact on 5-year overall (OS) and disease-free survival (DFS). RESULTS: A total of 378 patients underwent mastectomy alone (157, 41%) or mastectomy with reconstruction (221, 59%) for Stage I-III disease with a median follow-up of 5 years. Postoperative complications occurred in 186 patients (49%), requiring non-surgical (I/II = 83, 22%) or surgical (IIIa/IIIb = 103, 27%) management. Wound complications occurred in 140 patients (37%). Reconstruction was associated with a higher rate of complication (P < 0.001). Postoperative complications after mastectomy (with or without reconstruction) did not significantly affect OS or DFS. Wound complications also showed no significant effect on OS or DFS following mastectomy alone, or mastectomy with reconstruction. CONCLUSIONS: Postoperative complications after mastectomy, with or without reconstruction, bear no significant impact on 5-year survival.

Opiate Pain Medication Consumption in Cigarette Smokers following Total Hip Arthroplasty.

Purpose The purpose of the present study was to assess perception of pain and pain management in smokers versus nonsmokers who received a total hip arthroplasty (THA). Methods Patients who underwent THA from 2010 to 2016 were propensity score matched 1:1 based on race, body mass index, age, and sex. This yielded 124 smokers and 124 nonsmokers. Pain intensity was quantified using area under the curve for visual analog scale pain scores. Opioid consumption was determined using a morphine milliequivalent (mEq) conversion algorithm. An independent samples t -test and Chi-square analysis was conducted to assess continuous and categorical variables respectively. Results Smokers experienced a nonsignificantly increased pain intensity (198.1 vs. 185.7; p = 0.063). Smokers demonstrated significantly higher opioid consumption in both immediate postoperative (65.9 vs. 59.3 mEq; p = 0.045) and 90 days postoperative periods (619.9 vs. 458.9 mEq; p = 0.029). Conclusion Our study demonstrated a nonsignificantly increased pain intensity, and (in both the immediate and 90 days postoperative periods) a significantly higher opioid consumption following THA in patients who smoke cigarettes. This may be due to a relatively small effect size, warranting the need for larger prospective studies. Nevertheless, arthroplasty surgeons should encourage preoperative smoking cessation and alternative nonopioid analgesics to smoking patients receiving THA. Level of Evidence This is a level III, retrospective cohort study.

Spectroscopic Studies on the Metal-Insulator Transition Mechanism in Correlated Materials.

The metal-insulator transition (MIT) in correlated materials is a novel phenomenon that accompanies a large change in resistivity, often many orders of magnitude. It is important in its own right but its switching behavior in resistivity can be useful for device applications. From the material physics point of view, the starting point of the research on the MIT should be to understand the microscopic mechanism. Here, an overview of recent efforts to unravel the microscopic mechanisms for various types of MITs in correlated materials is provided. Research has focused on transition metal oxides (TMOs), but transition metal chalcogenides have also been studied. Along the way, a new class of MIT materials is discovered, the so-called relativistic Mott insulators in 5d TMOs. Distortions in the MO6 (M = transition metal) octahedron are found to have a large and peculiar effect on the band structure in an orbital dependent way, possibly paving a way to the orbital selective Mott transition. In the final section, the character of the materials suitable for applications is summarized, followed by a brief discussion of some of the efforts to control MITs in correlated materials, including a dynamical approach using light.

Mutational patterns in chemotherapy resistant muscle-invasive bladder cancer.

Despite continued widespread use, the genomic effects of cisplatin-based chemotherapy and implications for subsequent treatment are incompletely characterized. Here, we analyze whole exome sequencing of matched pre- and post-neoadjuvant cisplatin-based chemotherapy primary bladder tumor samples from 30 muscle-invasive bladder cancer patients. We observe no overall increase in tumor mutational burden post-chemotherapy, though a significant proportion of subclonal mutations are unique to the matched pre- or post-treatment tumor, suggesting chemotherapy-induced and/or spatial heterogeneity. We subsequently identify and validate a novel mutational signature in post-treatment tumors consistent with known characteristics of cisplatin damage and repair. We find that post-treatment tumor heterogeneity predicts worse overall survival, and further observe alterations in cell-cycle and immune checkpoint regulation genes in post-treatment tumors. These results provide insight into the clinical and genomic dynamics of tumor evolution with cisplatin-based chemotherapy, suggest mechanisms of clinical resistance, and inform development of clinically relevant biomarkers and trials of combination therapies.

A highly selective fluorescent ESIPT probe for the dual specificity phosphatase MKP-6.

A highly selective fluorescent probe for a protein tyrosine phosphatase (PTP) was designed by a simple phosphorylation of the 2-(2'-hydroxyphenyl)benzothiazole (HBT) chromophore: upon selective enzymatic hydrolysis, an excited-state intramolecular proton transfer (ESIPT) occurs, resulting in a large Stokes shift.