Modern microprocessor built from complementary carbon nanotube transistors.

Electronics is approaching a major paradigm shift because silicon transistor scaling no longer yields historical energy-efficiency benefits, spurring research towards beyond-silicon nanotechnologies. In particular, carbon nanotube field-effect transistor (CNFET)-based digital circuits promise substantial energy-efficiency benefits, but the inability to perfectly control intrinsic nanoscale defects and variability in carbon nanotubes has precluded the realization of very-large-scale integrated systems. Here we overcome these challenges to demonstrate a beyond-silicon microprocessor built entirely from CNFETs. This 16-bit microprocessor is based on the RISC-V instruction set, runs standard 32-bit instructions on 16-bit data and addresses, comprises more than 14,000 complementary metal-oxide-semiconductor CNFETs and is designed and fabricated using industry-standard design flows and processes. We propose a manufacturing methodology for carbon nanotubes, a set of combined processing and design techniques for overcoming nanoscale imperfections at macroscopic scales across full wafer substrates. This work experimentally validates a promising path towards practical beyond-silicon electronic systems.

A genome-wide meta-analysis of palmoplantar pustulosis implicates TH2 responses and cigarette smoking in disease pathogenesis.

BACKGROUND: Palmoplantar pustulosis (PPP) is an inflammatory skin disorder that mostly affects smokers and manifests with painful pustular eruptions on the palms and soles. Although the disease can present with concurrent plaque psoriasis, TNF and IL-17/IL-23 inhibitors show limited efficacy. There is therefore a pressing need to uncover PPP disease drivers and therapeutic targets. OBJECTIVES: We sought to identify genetic determinants of PPP and investigate whether cigarette smoking contributes to disease pathogenesis. METHODS: We performed a genome-wide association meta-analysis of 3 North-European cohorts (n = 1,456 PPP cases and 402,050 controls). We then used the scGWAS program to investigate the cell-type specificity of the association signals. We also undertook genetic correlation analyses to examine the similarities between PPP and other immune-mediated diseases. Finally, we applied Mendelian randomization to analyze the causal relationship between cigarette smoking and PPP. RESULTS: We found that PPP is not associated with the main genetic determinants of plaque psoriasis. Conversely, we identified genome-wide significant associations with the FCGR3A/FCGR3B and CCHCR1 loci. We also observed 13 suggestive (P < 5 × 10-6) susceptibility regions, including the IL4/IL13 interval. Accordingly, we demonstrated a significant genetic correlation between PPP and TH2-mediated diseases such as atopic dermatitis and ulcerative colitis. We also found that genes mapping to PPP-associated intervals were preferentially expressed in dendritic cells and often implicated in T-cell activation pathways. Finally, we undertook a Mendelian randomization analysis, which supported a causal role of cigarette smoking in PPP. CONCLUSIONS: The first genome-wide association study of PPP points to a pathogenic role for deregulated TH2 responses and cigarette smoking.

The association between gender and industry payments to minimally invasive surgeons.

BACKGROUND: It is unknown if there are differential industry payments to surgeons based on gender. This study aims to examine differences by gender for industry relations with minimally invasive surgeons, using speakers at the SAGES Annual Meeting as a proxy for key thought leaders in minimally invasive surgery. METHODS: We queried the Open Payments Database for payments made to US speakers from the 2023 SAGES meeting. All payments from the prior fiscal year prior were collected. The National Provider Identity (NPI) Registry was cross-referenced to determine surgeon's self-reported gender. Industry sponsors were analyzed based on differences in payments made. RESULTS: A total of 305 speakers were assessed, with 175 (57.4%) males and 130 (42.6%) females. Of the 305 speakers, 246 were listed in the OPD. There were 145/175 (82.8%) males who were received general payments, compared to 101/130 (77.6%) females (p = 0.326). The total amount of industry payments was $2,894,287 for males and $1,539,481 for females. Median payments were 2.8X higher for males ($4657, IQR $422-$15,798) than females ($1651, IQR $299-$9005) (p = 0.05). CONCLUSIONS: Despite efforts to decrease gender bias in surgery, there remains a significant and substantial difference in payments towards male and female surgeons via industry relationships. This has potential downstream effects on career development, consulting and research opportunities, and development of new devices.

Laparoscopic Heller myotomy with Toupet fundoplication: revisiting GERD in treated achalasia.

INTRODUCTION: With the advent of the laparoscopic era in the 1990s, laparoscopic Heller myotomy replaced pneumatic dilation as the first-line treatment for achalasia. An advantage of this approach was the addition of a fundoplication to reduce gastroesophageal reflux disease (GERD). More recently, Peroral Endoscopic Myotomy has competed for first-line therapy, but the postoperative GERD may be a weakness. This study leverages our experience to characterize GERD following LHM with Toupet fundoplication (LHM+T ) so that other treatments can be appropriately compared. METHODS: A single-institution retrospective review of adult patients with achalasia who underwent LHM+T from January 2012 to April 2022 was performed. We obtained routine 6-month postoperative pH studies and patient symptom questionnaires. Differences in questionnaires and reflux symptoms in relation to pH study were explored via Kruskal-Wallis test or chi-square tests. RESULTS: Of 170 patients who underwent LHM+T , 51 (30%) had postoperative pH testing and clinical symptoms evaluation. Eleven (22%) had an abnormal pH study; however, upon manual review, 5 of these (45.5%) demonstrated low-frequency, long-duration reflux events, suggesting poor esophageal clearance of gastric refluxate and 6/11 (54.5%) had typical reflux episodes. Of the cohort, 7 (15.6%) patients reported GERD symptoms. The median [IQR] severity was 1/10 [0, 3] and median [IQR] frequency was 0.5/4 [0, 1]. Patients with abnormal pH reported more GERD symptoms than patients with a normal pH study (3/6, 50% vs 5/39, 12.8%, p = 0.033). Those with a poor esophageal clearance pattern (n = 5) reported no concurrent GERD symptoms. CONCLUSION: The incidence of GERD burden after LHM+T is relatively low; however, the nuances relevant to accurate diagnosis in treated achalasia patients must be considered. Symptom correlation to abnormal pH study is unreliable making objective postoperative testing important. Furthermore, manual review of abnormal pH studies is necessary to distinguish GERD from poor esophageal clearance.

The posterolateral ligament of the elbow: anatomy and clinical relevance.

BACKGROUND: The posterolateral capsule was recognized in the past as an important structure for elbow stability but was later disregarded. Two recent biomechanical studies demonstrated its role in preventing posterolateral instability, and thus it should be identified as a distinct ligament: the posterolateral ligament (PLL). This study includes 2 parts: an anatomic study of the PLL's footprint and a collection of 5 cases of pathologic lesions of the PLL. METHODS: Six cadaveric upper limbs were assessed. The attachments of the PLL were dissected, the footprints were marked and photographed, and the 2-dimensional area and length were measured. RESULTS: The mean proximal attachment dimensions were a length of 13 mm and an area of 101 mm2, and the mean distal attachment dimensions were 19 mm and 111 mm2, respectively. There were 2 cases of posterolateral elbow pain in professional cricket bowlers, diagnosed radiographically as enthesopathy of the PLL's proximal attachment on the posterior capitellum, probably due to repeated forced hyperextension of the elbow. Both patients were treated by débridement of the posterior capitellum and reattachment of the PLL, with complete resolution of symptoms. In addition, there were 3 cases of clinical posterolateral rotatory instability in young patients. Two athletes had an isolated acute tear of the PLL, and on physical examination, both had positive posterior draw test results but negative pivot-shift test results. Both underwent elbow arthroscopy and repair of the PLL with resolution of symptoms. The third patient had long-standing recurrent elbow instability, following a failed lateral ulnar collateral ligament reconstruction, in the presence of an Osborne-Cotterill lesion. He underwent revision lateral ulnar collateral ligament reconstruction, bone grafting of the bony lesion, and reattachment of the PLL, with complete resolution of symptomatic posterolateral rotatory instability. CONCLUSIONS: The PLL of the elbow has a significant role in the elbow's posterolateral stability. Its footprints were described, and its clinical significance was demonstrated in cases of elbow instability caused by acute ligament tears and elbow pain due to ligament enthesopathy. Surgeons should be aware of this structure and potential pathology related to its injury.

Loose Coupling between the Voltage Sensor and the Activation Gate in Mammalian HCN Channels Suggests a Gating Mechanism.

Voltage-gated potassium (Kv) channels and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels share similar structures but have opposite gating polarity. Kv channels have a strong coupling (>109) between the voltage sensor (S4) and the activation gate: when S4s are activated, the gate is open to >80% but, when S4s are deactivated, the gate is open <10-9 of the time. Using noise analysis, we show that the coupling between S4 and the gate is <200 in HCN channels. In addition, using voltage clamp fluorometry, locking the gate open in a Kv channel drastically altered the energetics of S4 movement. In contrast, locking the gate open or decreasing the coupling between S4 and the gate in HCN channels had only minor effects on the energetics of S4 movement, consistent with a weak coupling between S4 and the gate. We propose that this loose coupling is a prerequisite for the reversed voltage gating in HCN channels.

Anticarcinogenic impact of extracellular vesicles (exosomes) from cord blood stem cells in malignant melanoma: A potential biological treatment.

Incidence of Malignant Melanoma has become the 5th in the UK. To date, the major anticancer therapeutics include cell therapy, immunotherapy, gene therapy and nanotechnology-based strategies. Recently, extracellular vesicles, especially exosomes, have been highlighted for their therapeutic benefits in numerous chronic diseases. Exosomes display multifunctional properties, including inhibition of cancer cell proliferation and initiation of apoptosis. In the present in vitro study, the antitumour effect of cord blood stem cell (CBSC)-derived exosomes was confirmed by the CCK-8 assay (p < 0.05) on CHL-1 melanoma cells and improve the repair mechanism on lymphocytes from melanoma patients. Importantly, no significant effect was observed in healthy lymphocytes when treated with the exosome concentrations at 24, 48 and 72 h. Comet assay results (OTM and %Tail DNA) demonstrated that the optimal exosome concentration showed a significant impact (p < 0.05) in lymphocytes from melanoma patients whilst causing no significant DNA damage in lymphocytes of healthy volunteers was 300 µg/ml. Similarly, the Comet assay results depicted significant DNA damage in a melanoma cell line (CHL-1 cells) treated with CBSC-derived exosomes, both the cytotoxicity of CHL-1 cells treated with CBSC-derived exosomes exhibited a significant time-dependent decrease in cell survival. Sequencing analysis of CBSC exosomes showed the presence of the let-7 family of miRNAs, including let-7a-5p, let-7b-5p, let-7c-5p, let-7d-3p, let-7d-5p and two novel miRNAs. The potency of CBSC exosomes in inhibiting cancer progression in lymphocytes from melanoma patients and CHL-1 cells whilst causing no harm to the healthy lymphocytes makes it a potential candidate as an anticancer therapy.

Mapping of glutamate metabolism using 1H FID-MRSI after oral administration of [1-13C]Glc at 9.4 T.

Glutamate is the major excitatory transmitter in the brain and malfunction of the related metabolism is associated with various neurological diseases and disorders. The observation of labeling changes in the spectra after the administration of a 13C labelled tracer is a common tool to gain better insights into the function of the metabolic system. But so far, only a very few studies presenting the labeling effects in more than two voxels to show the spatial dependence of metabolism. In the present work, the labeling effects were measured in a transversal plane in the human brain using ultra-short TE and TR 1H FID-MRSI. The measurement set-up was most simple: The [1-13C]Glc was administered orally instead of intravenous and the spectra were measured with a pure 1H technique without the need of a 13C channel (as Boumezbeur et al. demonstrated in 2004). Thus, metabolic maps and enrichment curves could be obtained for more metabolites and in more voxels than ever before in human brain. Labeling changes could be observed in [4-13C]glutamate, [3-13C]glutamate+glutamine, [2-13C]glutamate+glutamine, [4-13C]glutamine, and [3-13C]aspartate with a high temporal (3.6 min) and spatial resolution (32 × 32 grid with nominal voxel size of 0.33 µL) in five volunteers.

Loss-of-Function Myeloperoxidase Mutations Are Associated with Increased Neutrophil Counts and Pustular Skin Disease.

The identification of disease alleles underlying human autoinflammatory diseases can provide important insights into the mechanisms that maintain neutrophil homeostasis. Here, we focused our attention on generalized pustular psoriasis (GPP), a potentially life-threatening disorder presenting with cutaneous and systemic neutrophilia. Following the whole-exome sequencing of 19 unrelated affected individuals, we identified a subject harboring a homozygous splice-site mutation (c.2031-2A>C) in MPO. This encodes myeloperoxidase, an essential component of neutrophil azurophil granules. MPO screening in conditions phenotypically related to GPP uncovered further disease alleles in one subject with acral pustular psoriasis (c.2031-2A>C;c.2031-2A>C) and in two individuals with acute generalized exanthematous pustulosis (c.1705C>T;c.2031-2A>C and c.1552_1565del;c.1552_1565del). A subsequent analysis of UK Biobank data demonstrated that the c.2031-2A>C and c.1705C>T (p.Arg569Trp) disease alleles were also associated with increased neutrophil abundance in the general population (p = 5.1 × 10-6 and p = 3.6 × 10-5, respectively). The same applied to three further deleterious variants that had been genotyped in the cohort, with two alleles (c.995C>T [p.Ala332Val] and c.752T>C [p.Met251Thr]) yielding p values < 10-10. Finally, treatment of healthy neutrophils with an MPO inhibitor (4-Aminobenzoic acid hydrazide) increased cell viability and delayed apoptosis, highlighting a mechanism whereby MPO mutations affect granulocyte numbers. These findings identify MPO as a genetic determinant of pustular skin disease and neutrophil abundance. Given the recent interest in the development of MPO antagonists for the treatment of neurodegenerative disease, our results also suggest that the pro-inflammatory effects of these agents should be closely monitored.

Test-retest reproducibility of human brain multi-slice 1 H FID-MRSI data at 9.4T after optimization of lipid regularization, macromolecular model, and spline baseline stiffness.

PURPOSE: This study analyzes the effects of retrospective lipid suppression, a simulated macromolecular prior knowledge and different spline baseline stiffness values on 9.4T multi-slice proton FID-MRSI data spanning the whole cerebrum of human brain and the reproducibility of respective metabolite ratio to total creatine (/tCr) maps for 10 brain metabolites. METHODS: Measurements were performed twice on 5 volunteers using a short TR and TE FID MRSI 2D sequence at 9.4T. The effects of retrospective lipid L2-regularization, macromolecular spectrum and different LCModel baseline flexibilities on SNR, FWHM, fitting residual, Cramér-Rao lower bound, and metabolite ratio maps were investigated. Intra-subject, inter-session coefficient of variation and the test-retest reproducibility of the mean metabolite ratios (/tCr) of each slice was calculated. RESULTS: Transversal, sagittal, and coronal slices of many metabolite ratio maps correspond to the anatomically expected concentration relations in gray and white matter for the majority of the cerebrum when using a flexible baseline in LCModel fit. Results from the second measurements of the same subjects show that slice positioning and data quality correlate significantly to the first measurement. L2-regularization provided effective suppression of lipid-artifacts, but should be avoided if no artifacts are detected. CONCLUSION: Reproducible concentration ratio maps (/tCr) for 4 metabolites (total choline, N-acetylaspartate, glutamate, and myoinositol) spanning the majority of the cerebrum and 6 metabolites (N-acetylaspartylglutamate, γ-aminobutyric acid, glutathione, taurine, glutamine, and aspartate) covering 32 mm in the upper part of the brain were acquired at 9.4T using multi-slice FID MRSI with retrospective lipid suppression, a macromolecular spectrum and a flexible LCModel baseline.

Application of the acquisition of data for outcomes and procedure transfer (ADOPT) method to a hands-on course for teaching extended-view totally extraperitoneal (eTEP) hernia repair to practicing surgeons.

BACKGROUND: After completion of training, practicing surgeons rely on hands-on courses to expand their procedure armamentarium and improve their surgical technique. However, such courses vary in standardized teaching methods. SAGES developed the Acquisition of Data for Outcomes and Procedure Transfer (ADOPT) program as a method of longitudinal instruction utilizing standardized teaching techniques, mentorship, and webinars to cover additional techniques. This study examines the adoption of learned techniques and participant confidence before and after an ADOPT course focused on extended-view totally extraperitoneal (eTEP) hernia repair. METHODS: A hands-on course focused on eTEP hernia repair was conducted with enrollment capped at 10 participants. Pre-course and post-course surveys at 3, 6, and 12 months determined implementation of the learned procedure, case volume, and confidence with eTEP skills. A 5-point Likert scale (1 = not confident at all to 5 = completely confident) assessed confidence levels. Survey responses were summarized using descriptive statistics. RESULTS: Of the 10 participants, 10 (100%) completed the pre-course survey, and 7 (70%) completed at least one post-course survey. Median age was 48.5 years (36,56) with a median of 16 years (2,23) in practice, mostly in the community setting (70%). After the course, 50% had performed an eTEP procedure, and 100% reported considering this technique during surgical planning. Participants reported higher confidence in eTEP-specific skills at three months post-course from pre-course levels. The highest change in confidence was seen for the following skills: accessing the retromuscular/extraperitoneal space for ventral hernia and recognizing when the linea alba has been violated, p < 0.05. CONCLUSION: This study shows that rapid incorporation of learned techniques can be achieved through the ADOPT format. Furthermore, through longitudinal mentorship and a structured hands-on course, the ADOPT course supports practicing surgeons to attain autonomy and confidence even when teaching a relatively technically challenging procedure, such as eTEP.

Type II hiatal hernias: do they exist or are they actually parahiatal hernias?

BACKGROUND: Type II hiatal hernias (HH) are characterized by a portion of the gastric fundus located above the esophageal hiatus adjacent to the esophagus while the gastroesophageal junction (GEJ) remains fixed below the esophageal hiatus. This type of HH has been called the "true" paraesophageal hernia (PEH) because the fundus appears to the side of the esophagus. In our experience, Type II HHs are occasionally identified on radiographic testing, however they are rarely, if ever, confirmed intraoperatively. This led to our question: Does Type II HH exist? METHODS: We searched for evidence of type II HH in three locations: 1. Retrospective review of all first-time PEH repairs (excluding Type I HHs and re-operative cases) performed at the University of Washington Medical Center from 1994 to 2021; 2. Operative videos available on YouTube and WebSurg websites; and 3. Abstracts from the SAGES annual meetings from 2005 to 2021. RESULTS: We found no evidence of Type II HH in any of our three searches. We performed 846 PEH repairs: 760 Type III, 75 Type IV, and 11 parahiatal. Upon website video review, we found only one possible type II hernia, though it too was likely a para-hiatal hernia. No video or case presentations of a type II HH were identified within SAGES annual meeting abstracts. CONCLUSION: Type II HHs do not exist as they are currently defined. Although uncommon, parahiatal hernia can easily be misinterpreted as Type II HH. We should consider changing the hiatal hernia classification system to prevent ongoing clinical confusion.

The environmental impact of surgical telemedicine: life cycle assessment of virtual vs. in-person preoperative evaluations for benign foregut disease.

BACKGROUND: Health care accounts for almost 10% of the United States' greenhouse gas emissions, accounting for a loss of 470,000 disability-adjusted life years based on the health effects of climate change. Telemedicine has the potential to decrease health care's carbon footprint by reducing patient travel and clinic-related emissions. At our institution, telemedicine visits for evaluation of benign foregut disease were implemented for patient care during the COVID-19 pandemic. We aimed to estimate the environmental impact of telemedicine usage for these clinic encounters. METHODS: We used life cycle assessment (LCA) to compare greenhouse gas (GHG) emissions for an in-person and a telemedicine visit. For in-person visits, travel distances to clinic were retrospectively assessed from 2020 visits as a representative sample, and prospective data were gathered on materials and processes related to in-person clinic visits. Prospective data on the length of telemedicine encounters were collected and environmental impact was calculated for equipment and internet usage. Upper and lower bounds scenarios for emissions were generated for each type of visit. RESULTS: For in-person visits, 145 patient travel distances were recorded with a median [IQR] distance travel distance of 29.5 [13.7, 85.1] miles resulting in 38.22-39.61 carbon dioxide equivalents (kgCO2-eq) emitted. For telemedicine visits, the mean (SD) visit time was 40.6 (17.1) min. Telemedicine GHG emissions ranged from 2.26 to 2.99 kgCO2-eq depending on the device used. An in-person visit resulted in 25 times more GHG emissions compared to a telemedicine visit (p < 0.001). CONCLUSION: Telemedicine has the potential to decrease health care's carbon footprint. Policy changes to facilitate telemedicine use are needed, as well as increased awareness of potential disparities of and barriers to telemedicine use. Moving toward telemedicine preoperative evaluations in appropriate surgical populations is a purposeful step toward actively addressing our role in health care's large carbon footprint.

Predicting Wrist Posture during Occupational Tasks Using Inertial Sensors and Convolutional Neural Networks.

Current methods for ergonomic assessment often use video-analysis to estimate wrist postures during occupational tasks. Wearable sensing and machine learning have the potential to automate this tedious task, and in doing so greatly extend the amount of data available to clinicians and researchers. A method of predicting wrist posture from inertial measurement units placed on the wrist and hand via a deep convolutional neural network has been developed. This study has quantified the accuracy and reliability of the postures predicted by this system relative to the gold standard of optoelectronic motion capture. Ten participants performed 3 different simulated occupational tasks on 2 occasions while wearing inertial measurement units on the hand and wrist. Data from the occupational task recordings were used to train a convolutional neural network classifier to estimate wrist posture in flexion/extension, and radial/ulnar deviation. The model was trained and tested in a leave-one-out cross validation format. Agreement between the proposed system and optoelectronic motion capture was 65% with κ = 0.41 in flexion/extension and 60% with κ = 0.48 in radial/ulnar deviation. The proposed system can predict wrist posture in flexion/extension and radial/ulnar deviation with accuracy and reliability congruent with published values for human estimators. This system can estimate wrist posture during occupational tasks in a small fraction of the time it takes a human to perform the same task. This offers opportunity to expand the capabilities of practitioners by eliminating the tedium of manual postural assessment.

Detecting subject-specific fatigue-related changes in lifting kinematics using a machine learning approach.

Individual responses to fatigue have been observed in lifting kinematics, suggesting a subject-specific approach is necessary for fatigue identification. One-class support vector machines (OCSVM) may provide an objective method to classify fatigue-related kinematic changes during repetitive lifting. Participants completed a repetitive lifting protocol while motion capture recorded lifting motions. Subject-specific kinematics from participants' first 35% of lifts trained OCSVM decision boundaries. The remaining lifts were separated into test sets and classified against the decision boundary to identify the percentage of outlier lifts within each test set. Spearman's correlation assessed if the test sets' percentage of outlier lifts increased concurrently with participants' rating of perceived exertion (RPE). Significant positive associations were found for participants who demonstrated evidence of fatigue, while no significant associations were found for participants who did not demonstrate evidence of fatigue. These results demonstrate the prospective efficacy of an outlier detection tool for fatigue detection during repetitive lifting.Practitioner Summary: An objective subject-specific fatigue detection method is desired for workplace tasks, such as lifting. An outlier detection machine learning approach was identified when lifting movement patterns changed from baseline throughout a repetitive lifting protocol. Participants who demonstrated an increase in outlier movement patterns had a concurrent increase in self-reported fatigue.

Quantitative T1-relaxation corrected metabolite mapping of 12 metabolites in the human brain at 9.4 T.

Magnetic resonance spectroscopic imaging (MRSI) is a non-invasive imaging modality that enables observation of metabolites. Applications of MRSI for neuroimaging have shown promise for monitoring and detecting various diseases. This study builds off previously developed techniques of short TR, 1H FID MRSI by correcting for T1-weighting of the metabolites and utilizing an internal water reference to produce quantitative (mmol kg-1) metabolite maps. This work reports and shows quantitative metabolite maps for 12 metabolites for a single slice. Voxel-specific T1-corrections for water are common in MRSI studies; however, most studies use either averaged T1-relaxation times to correct for T1-weighting of metabolites or omit this correction step entirely. This work employs the use of voxel-specific T1-corrections for metabolites in addition to water. Utilizing averaged T1-relaxation times for metabolites can bias metabolite maps for metabolites that have strong differences between T1-relaxation for GM and WM (i.e. Glu). This work systematically compares quantitative metabolite maps to single voxel quantitative results and qualitatively compares metabolite maps to previous works.

Relaxation-corrected macromolecular model enables determination of 1 H longitudinal T1 -relaxation times and concentrations of human brain metabolites at 9.4T.

PURPOSE: Ultrahigh field MRS has improved characterization of the neurochemical profile. To compare results obtained at 9.4T to those from lower field strengths, it is of interest to quantify the concentrations of metabolites measured. Thus, measuring T1 -relaxation times is necessary to correct for T1 -weighting that occurs in acquisitions for single-voxel spectroscopy and spectroscopic imaging. A macromolecule (MM) simulation model was developed to fit MM contributions to the short TE inversion series used to measure T1 -relaxation times. METHODS: An inversion series with seven time points was acquired with metabolite-cycled STEAM to estimate T1 -relaxation times of metabolites. A short TE was employed in this study to retain signals from metabolites with short T2 -relaxation times and J-couplings. The underlying macromolecule spectrum was corrected by developing a sequence-specific, relaxation-corrected simulated MM model. Quantification of metabolite peaks was performed using internal water referencing and relaxation corrections. RESULTS: T1 -relaxation times for metabolites range from approximately 750 to approximately 2000 ms and approximately 1000 to approximately 2400 ms in gray matter (GM)- and white matter (WM)- rich voxels, respectively. Quantification of metabolites was compared between GM and WM voxels, as well as between results that used a simulated MM spectrum against those that used an experimentally acquired MM spectrum. Metabolite concentrations are reported in mmol/kg quantities. CONCLUSION: T1 -relaxation times are reported for nonsinglet resonances for the first time at 9.4T by use of a MM simulation model to account for contributions from the MM spectrum. In addition to T1 -relaxation times, quantification results of metabolites from GM- and WM-rich voxels are reported.

The Cost of Guideline Adherence: A Multicenter Analysis of the Financial Implications of Adopting the US Multi-Society Task Force Polypectomy Guidelines.

GOAL: The goal of this study was to determine the financial impact of adopting the US Multi-Society Task Force (USMSTF) polypectomy guidelines on physician reimbursement and disposable equipment costs for gastroenterologists in the academic medical center and community practice settings. BACKGROUND: In 2020, USMSTF guidelines on polypectomy were introduced with a strong recommendation for cold snare rather than cold forceps technique for removing diminutive and small polyps. Polypectomy with snare technique reimburses physicians at a higher rate compared with cold forceps and also requires different disposable equipment. The financial implications of adopting these guidelines is unknown. MATERIALS AND METHODS: Patients that underwent screening colonoscopy where polypectomy was performed at an academic medical center (Loma Linda University Medical Center) and community practice medical center (Ascension Providence Hospital) between July 2018 and July 2019 were identified. The polypectomy technique performed during each procedure was determined (forceps alone, snare alone, forceps plus snare) along with the number and size of polyps as well as disposable equipment. Actual and projected provider reimbursement and disposable equipment costs were determined based on applying the new polypectomy guidelines. RESULTS: A total of 1167 patients underwent colonoscopy with polypectomy. Adhering to new guidelines would increase estimated physician reimbursement by 5.6% and 12.5% at academic and community practice sites, respectively. The mean increase in physician reimbursement per procedure was significantly higher at community practice compared with the academic setting ($29.50 vs. $14.13, P <0.00001). The mean increase in disposable equipment cost per procedure was significantly higher at the community practice setting ($6.11 vs. $1.97, P <0.00001). CONCLUSION: Adopting new polypectomy guidelines will increase physician reimbursement and equipment costs when colonoscopy with polypectomy is performed.

Characteristics and outcomes of patients undergoing paraesophageal hernia repair with selective use of biologic mesh.

BACKGROUND: The use of biologic mesh in paraesophageal hernia repair (PEHR) has been associated with decreased short-term recurrence but no statistically significant difference in long-term recurrence. Because of this, we transitioned from routine to selective use of mesh for PEHR. The aim of this study was to examine our indications for selective mesh use and to evaluate patient outcomes in this population. METHODS: We queried a prospectively maintained database for patients who underwent laparoscopic PEHR with biologic mesh from October 2015 to October 2018, then performed a retrospective chart review. The decision to use mesh was made intraoperatively by the surgeon. Recurrence was defined as the presence of > 2 cm intrathoracic stomach on postoperative upper gastrointestinal (UGI) series. RESULTS: Mesh was used in 61/169 (36%) of first-time PEHRs, and in 47/82 (57%) of redo PEHRs. Among first-time PEHRs, the indications for mesh included hiatal tension (85%), poor crural tissue quality (11%), or both (5%). Radiographic recurrence occurred in 15% of first-time patients (symptomatic N = 2, asymptomatic N = 3). There were no reoperations for recurrence. Among redo PEHRs, the indication for mesh was most commonly the redo nature of the repair itself (55%), but also hiatal tension (51%), poor crural tissue quality (13%), or both (4%). Radiographic recurrence occurred in 21% of patients (symptomatic N = 4, asymptomatic N = 1). There was 1 reoperation for recurrence in the redo-repair group. CONCLUSIONS: We selectively use biologic mesh in a third of our first-time repair patients and in over half of our redo-repair patients when there is a perceived high risk of recurrence based on hiatal tension, poor tissue quality, or prior recurrence. Despite the high risk for radiologic recurrence, there was only 1 reoperation for recurrence in the entire cohort.

The impact of socioeconomic status on telemedicine utilization during the COVID-19 pandemic among surgical clinics at an academic tertiary care center.

BACKGROUND: The COVID-19 pandemic caused many surgical providers to conduct outpatient evaluations using remote audiovisual conferencing technology (i.e., telemedicine) for the first time in 2020. We describe our year-long institutional experience with telemedicine in several general surgery clinics at an academic tertiary care center and examine the relationship between area-based socioeconomic measures and the likelihood of telemedicine participation. METHODS: We performed a retrospective review of our outpatient telemedicine utilization among four subspecialty clinics (including two acute care and two elective surgery clinics). Geocoding was used to link patient visit data to area-based socioeconomic measures and a multivariable analysis was performed to examine the relationship between socioeconomic indicators and patient participation in telemedicine. RESULTS: While total outpatient visits per month reached a nadir in April 2020 (65% decrease in patient visits when compared to January 2020), there was a sharp increase in telemedicine utilization during the same month (38% of all visits compared to 0.8% of all visits in the month prior). Higher rates of telemedicine utilization were observed in the two elective surgery clinics (61% and 54%) compared to the two acute care surgery clinics (14% and 9%). A multivariable analysis demonstrated a borderline-significant linear trend (p = 0.07) between decreasing socioeconomic status and decreasing odds of telemedicine participation among elective surgery visits. A sensitivity analysis to examine the reliability of this trend showed similar results. CONCLUSION: Telemedicine has many patient-centered benefits, and this study demonstrates that for certain elective subspecialty clinics, telemedicine may be utilized as the preferred method for surgical consultations. However, to ensure the equitable adoption and advancement of telemedicine services, healthcare providers will need to focus on mitigating the socioeconomic barriers to telemedicine participation.