Validation of MLC leaf open time calculation methods for PSQA in adaptive radiotherapy with tomotherapy units.

BACKGROUND: Treatment delivery safety and accuracy are essential to control the disease and protect healthy tissues in radiation therapy. For usual treatment, a phantom-based patient specific quality assurance (PSQA) is performed to verify the delivery prior to the treatment. The emergence of adaptive radiation therapy (ART) adds new complexities to PSQA. In fact, organ at risks and target volume re-contouring as well as plan re-optimization and treatment delivery are performed with the patient immobilized on the treatment couch, making phantom-based pretreatment PSQA impractical. In this case, phantomless PSQA tools based on multileaf collimator (MLC) leaf open times (LOTs) verifications provide alternative approaches for the Radixact® treatment units. However, their validity is compromised by the lack of independent and reliable methods for calculating the LOT performed by the MLC during deliveries. PURPOSE: To provide independent and reliable methods of LOT calculation for the Radixact® treatment units. METHODS: Two methods for calculating the LOTs performed by the MLC during deliveries have been implemented. The first method uses the signal recorded by the build-in detector and the second method uses the signal recorded by optical sensors mounted on the MLC. To calibrate the methods to the ground truth, in-phantom ionization chamber LOT measurements have been conducted on a Radixact® treatment unit. The methods were validated by comparing LOT calculations with in-phantom ionization chamber LOT measurements performed on two Radixact® treatment units. RESULTS: The study shows a good agreement between the two LOT calculation methods and the in-phantom ionization chamber measurements. There are no notable differences between the two methods and the same results were observed on the different treatment units. CONCLUSIONS: The two implemented methods have the potential to be part of a PSQA solution for ART in tomotherapy.

A smoothed corrected score approach for proportional hazards model with misclassified discretized covariates induced by error-contaminated continuous time-dependent exposure.

We consider the proportional hazards model in which the covariates include the discretized categories of a continuous time-dependent exposure variable measured with error. Naively ignoring the measurement error in the analysis may cause biased estimation and erroneous inference. Although various approaches have been proposed to deal with measurement error when the hazard depends linearly on the time-dependent variable, it has not yet been investigated how to correct when the hazard depends on the discretized categories of the time-dependent variable. To fill this gap in the literature, we propose a smoothed corrected score approach based on approximation of the discretized categories after smoothing the indicator function. The consistency and asymptotic normality of the proposed estimator are established. The observation times of the time-dependent variable are allowed to be informative. For comparison, we also extend to this setting two approximate approaches, the regression calibration and the risk-set regression calibration. The methods are assessed by simulation studies and by application to data from an HIV clinical trial.

Using 4D dose accumulation to calculate organ-at-risk dose deviations from motion-synchronized liver and lung tomotherapy treatments.

Tracking systems such as Radixact Synchrony change the planned delivery of radiation during treatment to follow the target. This is typically achieved without considering the location changes of organs at risk (OARs). The goal of this work was to develop a novel 4D dose accumulation framework to quantify OAR dose deviations due to the motion and tracked treatment. The framework obtains deformation information and the target motion pattern from a four-dimensional computed tomography dataset. The helical tomotherapy treatment plan is split into 10 plans and motion correction is applied separately to the jaw pattern and multi-leaf collimator (MLC) sinogram for each phase based on the location of the target in each phase. Deformable image registration (DIR) is calculated from each phase to the references phase using a commercial algorithm, and doses are accumulated according to the DIR. The effect of motion synchronization on OAR dose was analyzed for five lung and five liver subjects by comparing planned versus synchrony-accumulated dose. The motion was compensated by an average of 1.6 cm of jaw sway and by an average of 5.7% of leaf openings modified, indicating that most of the motion compensation was from jaw sway and not MLC changes. OAR dose deviations as large as 19 Gy were observed, and for all 10 cases, dose deviations greater than 7 Gy were observed. Target dose remained relatively constant (D95% within 3 Gy), confirming that motion-synchronization achieved the goal of maintaining target dose. Dose deviations provided by the framework can be leveraged during the treatment planning process by identifying cases where OAR doses may change significantly from their planned values with respect to the critical constraints. The framework is specific to synchronized helical tomotherapy treatments, but the OAR dose deviations apply to any real-time tracking technique that does not consider location changes of OARs.

Extended Noninvasive Glucose Monitoring in the Interstitial Fluid Using an Epidermal Biosensing Patch.

An effective, noninvasive glucose monitoring technology could be a pivotal factor for addressing the major unmet needs for managing diabetes mellitus (DM). Here, we describe a skin-worn, disposable, wireless electrochemical biosensor for extended noninvasive monitoring of glucose in the interstitial fluid (ISF). The wearable platform integrates three components: a screen-printed iontophoretic electrode system for ISF extraction by reverse iontophoresis (RI), a printed three-electrode amperometric glucose biosensor, and an electronic interface for control and wireless communication. Prolonged on-body glucose monitoring of up to 8 h, including clinical trials conducted in individuals with and without DM, demonstrated good correlation between glucose blood and ISF concentrations and the ability to monitor dynamically changing glucose levels upon food consumption, with no evidence of skin irritation or discomfort. Such successful extended operation addresses the challenges reported for the GlucoWatch platform by using a lower RI current density at shorter extraction times, along with a lower measurement frequency. Such a noninvasive skin-worn platform could address long-standing challenges with existing glucose monitoring platforms.

A unique case of Lemierre's syndrome status post blunt cervical trauma.

BACKGROUND: Lemierre's syndrome is a rare but potentially fatal condition. The course is characterized by acute tonsillopharyngitis, bacteremia, internal jugular vein thrombosis, and septic embolization. There have been some cases secondary to penetrating trauma to the neck. Literature review has yielded no cases secondary to blunt neck trauma in the absence of oropharyngeal injury. We aim to shed light on this unique cause of Lemierre's syndrome, so as to raise the index of suspicion for clinicians working up patients with blunt cervical trauma. METHODS: We present a case of a 25-year-old male restrained driver who presented with left neck and shoulder pain with a superficial abrasion to the left neck from the seatbelt who was discharged same day by the Emergency Room physicians. He returned to the Emergency Department two days later with abdominal pain. As a part of his repeat evaluation, a set of blood cultures were sent and was sent home that day. The patient was called back to the hospital one day later as preliminary blood cultures were positive for Gram positive cocci and Gram negative anaerobes. Computerized tomography scan of the neck revealed extensive occlusive left internal jugular vein thrombosis and fluid collections concerning for abscesses, concerning for septic thrombophlebitis. The patient continued to decompensate, developing severe sepsis complicated by disseminated intravascular coagulation. RESULTS: The patient underwent a left neck exploration with en bloc resection of the left internal jugular vein, drainage of abscesses deep to the sternocleidomastoid, and washout/debridement of necrotic tissue. Direct laryngoscopy at the time of surgery revealed no injury to the aerodigestive tract. Wound cultures were consistent with blood cultures and grew Fusobacterium necrophorum, Staphylococcus epidermidis, and Methicillin-resistant staphylococcus aureus. The patient underwent two subsequent operative wound explorations without any evidence of residual infection. The patient was discharged home on postoperative day 13 on a course of antibiotics and aspirin. CONCLUSION: This case illustrates the importance of diagnosis of Lemierre's syndrome after an unconventional inciting event (blunt cervical trauma) and appropriate treatment.

SGLT-2 Inhibitors: A New Mechanism for Glycemic Control.

Glucosuria, the presence of glucose in the urine, has long been regarded as a consequence of uncontrolled diabetes. However, glucose excretion can be induced by blocking the activity of the renal sodium-glucose cotransporter 2 (SGLT-2). This mechanism corrects hyperglycemia independently of insulin. This article provides an overview of the paradigm shift that triggered the development of the SGLT-2 inhibitor class of agents and summarizes the available evidence from clinical studies to date.

Zooming In, Then Out: Why We Must Apply Human-Centered Design to Transform Diabetes Technology.

Technological advances in devices, such as continuous glucose monitors (CGMs) or intermittently scanned continuous glucose monitors (isCGMs), do not necessarily by themselves translate to improved clinical outcomes or quality of life. Human-centered design (HCD) is an accessible, flexible process that could contribute to reducing the gap between current challenges and more optimal future solutions, by continuing to refine crucial considerations, such as usability. Starting with understanding the unmet needs of patients, cultivating novel and different collaborations, and applying humility to humanize technology are three facets underlying this approach. Human-centered design can help expand our perspective to serve as another essential tool to help further refine diabetes technology.

Collaboratively Designing an App for a More Personalized, Community-Endorsed Continuous Glucose Monitoring Onboarding Experience: An Early Study.

BACKGROUND: Acclimating to a new technology device, such as a continuous glucose monitor (CGM), can be challenging. Current resources may not sufficiently answer questions patients living with diabetes (PWD) may have. We asked how we might improve the process to onboard a PWD to CGM. Our specific aims were (1) to develop, employing a co-designing approach, a prototype of an app for facilitating onboarding to CGM and (2) to obtain early feedback on its usability. METHODS: We applied a human-centered design (HCD) approach; this process first seeks to deeply understand the unmet needs and frustrations users face. After wearing a demonstration CGM; observing PWD onboarding with health care professionals (HCPs) in clinic; and interviewing 8 PWD and 2 HCP, we developed, tested, and refined a low-fidelity prototype of a clickable app. With insights from this initial round of feedback, we then created a high-fidelity prototype with 3 key features: (1) individual entry of goals and questions; (2) a daily progress tracker for these goals; and (3) a community portal that facilitates exchange of questions and answers. We used the validated System Usability Scale (SUS) to quantify user feedback. RESULTS: Focus group participants found our early app to be usable and acceptable. Measurement of usability by the SUS yielded a score of 74, which is above average (68) reported for all applications tested, per usability.gov. CONCLUSIONS: Our early prototype app is a more personalized, additional tool that could bridge an information and support gap for patients who are new to CGM. This app could also help PWD on an ongoing basis, by evolving with them to enhance ease and engagement with diabetes self-management.

Surgical stabilization of rib fractures in patients with pulmonary comorbidities.

INTRODUCTION: Prior studies have shown that the surgical stabilization of rib fractures (SSRF) for patients with multiple rib fractures is associated with improved outcomes by restoring chest wall integrity and decreasing time to return to prior functional status. It is unclear if patients with pulmonary comorbidities (PCM) would benefit from this procedure. OBJECTIVE: To compare the difference in morbidity and mortality of patients with multiple rib fractures undergoing SSRF who have underlying PCM to those who do not have PCM. METHODS: We performed a retrospective cohort study of patients with multiple rib fractures using data from the Trauma Quality Improvement Program (January 2015 to December 2018). Patients with penetrating injuries, those who died within the first 24 h, those with substantial head, spine, or abdominopelvic injuries, and those who were pregnant, were excluded. A PCM was defined as chronic lower respiratory disease, active smoking, or morbid obesity. Dichotomous outcomes were adjusted for potential confounders by creating a propensity score for PCM and applying inverse probability weighting. The propensity score accounted for multiple patient-level and hospital level covariates. Continuous outcomes were adjusted for these same covariates using multivariable quantile regression. RESULTS: Of the 4,084 patients who underwent SSRF, 3048 (75%) were males, the median age was 57 years [IQR 47, 66], and 1504 (37%) had at least one PCM. After adjusting for the propensity score, patients with PCM who underwent SSRF had no significant difference in mortality compared to those without PCM (absolute difference, 0.7% [95% CI -0.2, 1.7]). Similarly, there was no significant difference in time on the ventilator (0.6 days [-0.1, 1.4]). Patients with PCM, however, had a statistically significantly longer hospital LOS (0.8 days [0.3, 1.3]) and ICU LOS (0.6 days [0.1, 1.1]), higher risk of tracheostomy (2.7% [0.1, 4.6]) and higher probability of pulmonary complications (2.7% [1.2, 4.2]), compared to those without PCM. CONCLUSION: Among patients with multiple rib fractures who undergo SSRF, having a PCM did not result in a clinically important higher probability of dying or experiencing substantial morbidity. This factor should not exclude patients with PCM from receiving SSRF for multiple rib fractures but the small increased risk in morbidity should be discussed with patients prior to SSRF.

Sequential monoscopic image-guided motion compensation in tomotherapy stereotactic body radiotherapy (SBRT) for prostate cancer.

PURPOSE: To manage intra-fractional motions, recent developments in tomotherapy enable a unique capability of adjusting MLC/jaw to track the moving target based on the intra-fractional motions detected by sequential monoscopic imaging. In this study, we evaluated the effectiveness of motion compensation with a realistic imaging rate for prostate stereotactic body radiotherapy (SBRT). The obtained results will guide optimizing treatment parameters and image-guided radiation therapy (IGRT) in tomotherapy using this approach. METHODS: Ten retrospective prostate cases with actual prostate motion curves previously recorded through the Calypso system were used in this study. Based on the recorded peak-to-peak motion, these cases represented either large (> 5 mm) or median (≤ 5 mm) intra-fractional prostate motions. All the cases were re-planned on tomotherapy using 35 Gy/5 fractions SBRT regimen and three different jaw settings of 1 cm static, 2.5 cm static, and 2.5 cm dynamic jaw. Two motion compensation methods were evaluated: a complete compensation that adjusted the jaw and MLC every 0.1 s (the same rate as the Calypso motion trace), and a realistic compensation that adjusted the jaw and MLC at an average imaging interval of 6 s from sequential monoscopic images. An in-house 4D dose calculation software was then applied to calculate the dosimetric outcomes from the original motion-free plan, the motion-contaminated plan, and the two abovementioned motion-compensated plans. During the process, various imaging rates were also simulated in one case with unusually large motions to quantify the impact of the KV-imaging rate on the effectiveness of motion compensation. RESULTS: The effectiveness of motion compensation was evaluated based on the PTV coverage and OAR sparing. Without any motion-compensation, the PTV coverage (PTV V100%) of patients with large prostate motions decreased remarkably to 55%-82% when planning with the 1 cm jaw but to a less level of 67-94% with the 2.5 cm jaw. In contrast, motion compensation improved the PTV coverage (>92%) when combined with the 2.5 cm jaw, but less effective, around 75%-94%, with the 1 cm jaw. For OAR sparing, the bladder D1cc, bladder D10cc, and rectum D1cc all increased in the motion-contaminated plans. Motion compensation improved OAR sparing to the equivalent level of the original motion-free plans. For patients with median prostate motion, motion-induced degradation in PTV coverage was only observed when planning with the 1 cm jaw. After motion compensation, the PTV coverage improved to better than 94% for all three jaw settings. Additionally, the effectiveness of motion compensation depends on the imaging rate. Motion compensation with a typical rate of two KV images per gantry rotation effectively reduces motion-induced dosimetric uncertainties. However, a higher imaging rate is recommended when planning with a 1 cm jaw for patients with large motions. CONCLUSION: Our results demonstrated that the performance of sequential monoscopic imaging-guided motion compensation on tomotherapy depends on the amplitude of intra-fractional prostate motion, the plan parameter settings, especially jaw setting, gantry rotation, and the imaging rate for motion compensation. Creating a patient-specific imaging guidance protocol is essential to balance the effectiveness of motion compensation and achievable imaging rate for intra-fractional motion tracking.

AAPM Task Group Report 306: Quality control and assurance for tomotherapy: An update to Task Group Report 148.

Since the publication of AAPM Task Group (TG) 148 on quality assurance (QA) for helical tomotherapy, there have been many new developments on the tomotherapy platform involving treatment delivery, on-board imaging options, motion management, and treatment planning systems (TPSs). In response to a need for guidance on quality control (QC) and QA for these technologies, the AAPM Therapy Physics Committee commissioned TG 306 to review these changes and make recommendations related to these technology updates. The specific objectives of this TG were (1) to update, as needed, recommendations on tolerance limits, frequencies and QC/QA testing methodology in TG 148, (2) address the commissioning and necessary QA checks, as a supplement to Medical Physics Practice Guidelines (MPPG) with respect to tomotherapy TPS and (3) to provide risk-based recommendations on the new technology implemented clinically and treatment delivery workflow. Detailed recommendations on QA tests and their tolerance levels are provided for dynamic jaws, binary multileaf collimators, and Synchrony motion management. A subset of TPS commissioning and QA checks in MPPG 5.a. applicable to tomotherapy are recommended. In addition, failure mode and effects analysis has been conducted among TG members to obtain multi-institutional analysis on tomotherapy-related failure modes and their effect ranking.

High-dose MVCT image guidance for stereotactic body radiation therapy.

PURPOSE: Stereotactic body radiation therapy (SBRT) is a potent treatment for early stage primary and limited metastatic disease. Accurate tumor localization is essential to administer SBRT safely and effectively. Tomotherapy combines helical IMRT with onboard megavoltage CT (MVCT) imaging and is well suited for SBRT; however, MVCT results in reduced soft tissue contrast and increased image noise compared with kilovoltage CT. The goal of this work was to investigate the use of increased imaging doses on a clinical tomotherapy machine to improve image quality for SBRT image guidance. METHODS: Two nonstandard, high-dose imaging modes were created on a tomotherapy machine by increasing the linear accelerator (LINAC) pulse rate from the nominal setting of 80 Hz, to 160 Hz and 300 Hz, respectively. Weighted CT dose indexes (wCTDIs) were measured for the standard, medium, and high-dose modes in a 30 cm solid water phantom using a calibrated A1SL ion chamber. Image quality was assessed from scans of a customized image quality phantom. Metrics evaluated include: contrast-to-noise ratios (CNRs), high-contrast spatial resolution, image uniformity, and percent image noise. In addition, two patients receiving SBRT were localized using high-dose MVCT scans. Raw detector data collected after each scan were used to reconstruct standard-dose images for comparison. RESULTS: MVCT scans acquired using a pitch of 1.0 resulted in wCTDI values of 2.2, 4.7, and 8.5 cGy for the standard, medium, and high-dose modes respectively. CNR values for both low and high-contrast materials were found to increase with the square root of dose. Axial high-contrast spatial resolution was comparable for all imaging modes at 0.5 lp∕mm. Image uniformity was improved and percent noise decreased as the imaging dose increased. Similar improvements in image quality were observed in patient images, with decreases in image noise being the most notable. CONCLUSIONS: High-dose imaging modes are made possible on a clinical tomotherapy machine by increasing the LINAC pulse rate. Increasing the imaging dose results in increased CNRs; making it easier to distinguish the boundaries of low contrast objects. The imaging dose levels observed in this work are considered acceptable at our institution for SBRT treatments delivered in 3-5 fractions.

Laparoscopic sleeve gastrectomy for obesity: can it be considered a definitive procedure?

BACKGROUND: Providing bariatric surgery services to an inner-city population is a challenge. Laparoscopic sleeve gastrectomy (LSG) is an effective operation for morbid obesity with a relatively low complication rate. LSG appears to be a suitable alternative procedure for this group of patients. METHODS: This is a retrospective review and analysis of the experience with 185 consecutive LSGs that had completed at least 6 months follow-up. Eleven conversions from LSG to laparoscopic Roux-en-Y gastric bypass were excluded, leaving 174 patients for outcome analysis. Data collected were patient demographics, body mass index (BMI), comorbid conditions, operating time, length of hospital stay, and perioperative complications. Weight loss and resolution/improvement of comorbidities were analyzed. RESULTS: Mean patient age was 39.58 years and mean BMI was 48.97 kg/m(2). The percentage of patients with BMI > 50 kg/m(2) was 37.94%. Mean excess weight loss (EWL) was 44.76, 55.52, 59.22, and 58.92% at 6, 12, 24, and 36 months, respectively. Six patients (3.24%) lost less than 25% EWL. Thirteen patients (7.02%) regained an average of 13 lb after reaching a plateau. Resolution/improvement of comorbidities was 84% for diabetes mellitus, 49.99% for hypertension, 90% for asthma, 90.74% for obstructive sleep apnea, and 45.92% for gastroesophageal reflux disease symptoms (GERD). The mortality rate was zero in this series. Perioperative complications occurred in 26 patients (14.05%): four staple-line leaks (2.16%), four bleeds (2.16%), four obstructions (2.16%), five vomiting/dehydration (2.70%), six new onset of GERD symptoms (3.24%), two with pneumonia (1.08%), and one with pulmonary embolism (0.54%). CONCLUSION: LSG results in stable and adequate weight loss with resolution/improvement in comorbidities in a high percentage of patients. It can be considered a definitive operation for morbid obesity.

Is There an Age Cutoff for Intracranial Pressure Monitoring?: A Propensity Score Matched Analysis of the National Trauma Data Bank.

BACKGROUND: Despite mostly favorable past evidence for use of intracranial pressure monitoring (ICPM), more recent data question not only the indications but also the utility of ICPM. The Fourth Edition Brain Trauma Foundation guidelines offer limited indications for ICPM. Evidence supports ICPM for reducing mortality in patients with severe traumatic brain injury (TBI) and cites decreased survival in elderly patients. METHODS: All patients ≥ 18 years of age with isolated TBI, head Abbreviated Injury Scale (AIS) ≥ 3, and a Glasgow Coma Scale (GCS) ≤ 8 between 2008 and 2014 were included from the National Trauma Data Bank. Exclusion criteria were head AIS = 6 and death within 24 hours. Patients with and without ICPM were compared using TBI-specific variables. Patients were then matched via propensity-score matching (PSM), and the odds ratio (OR) of death with ICPM was determined using logistic regression modeling for 8 different age strata. RESULTS: A total of 23,652 patients with a mean age of 56 years, median head AIS of 4, median GCS of 3, and overall mortality of 29.2% were analyzed. After PSM, ICPM was associated with death beginning at the age stratum of 56-65 years. Intracranial pressure monitoring was associated with survival beginning at the age-group 36-45 years. DISCUSSION: Based on a large propensity-matched sample of TBI patients, ICPM was not associated with improved survival for TBI patients above 55 years of age. Until level 1 evidence is available, this age threshold should be considered for further prospective study in determining indications for ICPM.

When New York City was the COVID-19 pandemic epicenter: The impact on trauma care.

BACKGROUND: During early spring 2020, New York City (NYC) rapidly became the first US epicenter of the COVID-19 pandemic. With an unparalleled strain on health care resources, we sought to investigate the impact of the pandemic on trauma visits and mortality in the United States' largest municipal hospital system. METHODS: We conducted a retrospective multicenter cohort study of the five level 1 trauma centers in NYC's public health care system, New York City's Health and Hospitals Corporation. Clinical characteristics, mechanism of injury, and mortality of trauma patients presenting during the early pandemic (March 1, 2020, to May 31, 2020) were compared with a similar period in the previous 2 years. To account for important patient and hospital-level confounding variables, we created a propensity score for treatment and applied inverse probability weighting. RESULTS: In March to May 2020, there was a 25% decrease in median number of monthly trauma visits (693 vs. 528; p = 0.02) but a 50% increase (15% vs. 22%; p = <0.001) in patients presenting for penetrating injuries, compared with the same period for 2018 and 2019. Injured patients with COVID were significantly more likely to die compared with those without COVID-19 (10.5% vs. 3.6%; p < 0.001). Overall, there was no significant difference in mortality for non-COVID-injured New Yorkers cared for in 2020 compared with 2018 and 2019. Less severely injured non-COVID patients (Injury Severity Score, <15), however, were significantly more likely to die compared with this same subgroup in 2018 and 2019 (adjusted relative risk, 2.7 [95% confidence interval, 1.5-4.7]). CONCLUSION: Despite a decline in overall trauma visits during the early part of the COVID pandemic in NYC, there was a significant increase in the proportion of penetrating mechanisms. Less-injured non-COVID patients experienced an increase in mortality in the early pandemic, possibly from a depletion of human and hospital resources from the large influx of COVID patients. These data lend support to the safeguarding of trauma system resources in the event of a future pandemic. LEVEL OF EVIDENCE: Prognostic and Epidemiologic; Level III.

Hyper-Realistic Advanced Surgical Skills Package with Cut Suit Simulator Improves Trainee Surgeon Confidence in Operative Trauma.

BACKGROUND: Adequate exposure to operative trauma is not uniform across surgical residencies, and therefore it can be challenging to achieve competency during residency alone. This study introduced the Cut Suit surgical simulator with an Advanced Surgical Skills Package, which replicates traumatic bleeding and organ injury, into surgery resident training across multiple New York City trauma centers. METHODS: Trainees from 6 ACS-verified trauma centers participated in this prospective, observational trial. Groups of 3-5 trainees (post-graduate year 1-6) from 6 trauma centers within the largest public healthcare network in the U.S. participated. Residents were asked to perform various operative tasks including rescucitative thoracotomy, exploratory laprotomy, splenectomy, hepatorrhaphy, retroperitoneal exploration, and small bowel resection on a severely injured simulated patient. Pre- and post-course surveys were used to evaluate trainees' confidence performing these procedures and quizzes were used to evaluate participants' knowledge acquisition after the simulation. RESULTS: One hundred twenty-three surgery residents participated in the evaluation. 68% of participants agreed that the simulation was similar to actual surgery. After the simulation, the percentage of residents reporting being "more confident" or "most confident" in independently managing operative trauma patients increased by 42% (P < .01). There was a significant increase in the proportion of residents reporting being "more confident" or "most confident" managing all procedures performed. Post-activity quiz scores improved by an average of 20.4 points. DISCUSSION: The Cut Suit surgical simulator with ASSP is a realistic and useful adjunct in training surgeons to manage complex operative trauma.

A slit method to determine the focal spot size and shape of TomoTherapy system.

PURPOSE: To obtain accurate x-ray source profile measurements using a slit-collimator, the slit-collimator should have a narrow width, large height, and be positioned near the source. However, these conditions may not always be met. In this paper, the authors provide a detailed analysis of the slit measurement geometry and the relationship between the slit parameters and the measured x-ray source profile. The slit model allows the use of a shorter and more easily available slit-collimator, while accurate source profile measurements can still be obtained. METHODS: Measurements were performed with a variety of slit widths and/or slit to source distances. The relationship derived between the slit parameters and the measured profile was used to determine the true focal spot profile through a least square fit of the profile data. The model was verified by comparing the predicted profiles at a variety of slit-collimator parameters with the measured results on the TomoTherapy Hi-Art system. RESULTS: Both the treatment beam and the imaging beam were measured. For treatment mode, it was found that a source consisting of one Gaussian with a 0.75 mm full-width-half-maximum (FWHM) and 72% peak amplitude and a second Gaussian with a 2.27 mm FWHM and 18% peak amplitude matched measurement profiles. The overall source profile has a FWHM of 0.93 mm, but with a higher amplitude in the tail region than a single Gaussian. For imaging mode, the source consists of one Gaussian with a 0.68 mm FWHM and 82% peak amplitude and a second Gaussian with a 1.83 mm FWHM and 18% peak amplitude. The overall source profile has a FWHM of 0.77 mm. CONCLUSIONS: Our study of the focal spot measurement using slit-collimators showed that accurate source profile measurements can be achieved through fitting of measurement results at different slit widths and source-to-slit distances (SSD). Quantitative measurements of the TomoTherapy linac focal spot showed that the source distribution could be better described with a model consisting of two Gaussian components rather than a single Gaussian model as assumed in previous studies.

Do surgical emergencies stay at home? Observations from the first United States Coronavirus epicenter.

BACKGROUND: During the coronavirus disease 2019 pandemic, New York instituted a statewide stay-at-home mandate to lower viral transmission. While public health guidelines advised continued provision of timely care for patients, disruption of safety-net health care and public fear have been proposed to be related to indirect deaths because of delays in presentation. We hypothesized that admissions for emergency general surgery (EGS) diagnoses would decrease during the pandemic and that mortality for these patients would increase. METHODS: A multicenter observational study comparing EGS admissions from January to May 2020 to 2018 and 2019 across 11 NYC hospitals in the largest public health care system in the United States was performed. Emergency general surgery diagnoses were defined using International Classification Diseases, Tenth Revision, codes and grouped into seven common diagnosis categories: appendicitis, cholecystitis, small/large bowel, peptic ulcer disease, groin hernia, ventral hernia, and necrotizing soft tissue infection. Baseline demographics were compared including age, race/ethnicity, and payor status. Outcomes included coronavirus disease (COVID) status and mortality. RESULTS: A total of 1,376 patients were admitted for EGS diagnoses from January to May 2020, a decrease compared with both 2018 (1,789) and 2019 (1,668) (p < 0.0001). This drop was most notable after the stay-at-home mandate (March 22, 2020; week 12). From March to May 2020, 3.3%, 19.2%, and 6.0% of EGS admissions were incidentally COVID positive, respectively. Mortality increased in March to May 2020 compared with 2019 (2.2% vs. 0.7%); this difference was statistically significant between April 2020 and April 2019 (4.1% vs. 0.9%, p = 0.045). CONCLUSION: Supporting our hypothesis, the coronavirus disease 2019 pandemic and subsequent stay-at-home mandate resulted in decreased EGS admissions between March and May 2020 compared with prior years. During this time, there was also a statistically significant increase in mortality, which peaked at the height of COVID infection rates in our population. LEVEL OF EVIDENCE: Epidemiological, level IV.

Ketorolac Use for Pain Management in Trauma Patients With Rib Fractures Does not Increase of Acute Kidney Injury or Incidence of Bleeding.

INTRODUCTION: Ketorolac is useful in acute pain management to avoid opiate-related complications; however, some surgeons fear associated acute kidney injury (AKI) and bleeding despite a paucity of literature on ketorolac use in trauma patients. We hypothesized that our institution's use of intravenous ketorolac for rib fracture pain management did not increase the incidence of bleeding or AKI. METHODS: Rib fracture patients aged 15 years and above admitted between January 2016-June 2018 were identified in our trauma registry along with frequency of bleeding events. AKI was defined as ≥ 1.5x increase in serum creatinine from baseline measured on the second day of admission (after 24 hours of resuscitation) or an increase of ≥ .3 mg/dL over a 48-hour period. Patients receiving ketorolac were compared to patients with no ketorolac use. RESULTS: Two cohorts of 199 control and 205 ketorolac patients were found to be similar in age, gender, admission systolic blood pressure (SBP), injury severity score, intravenous radiocontrast received, and transfusion requirements. Analysis revealed no difference in frequency of AKI using both definitions (8% vs. 7.3%, P = .79) and (19.6% vs. 15.1%, P = .24), respectively, or bleeding events (2.5% vs. 0%, P = .03). Logistic regression demonstrated that ketorolac use was not an independent predictor for AKI but age and admission SBP < 90 were. CONCLUSION: Use of ketorolac in this cohort of trauma patients with rib fractures did not increase the incidence of AKI or bleeding events.

Prolonged use of spinal precautions is associated with increased morbidity in the trauma patient.

BACKGROUND: Patients who experience traumatic spine injuries remain in spinal precautions (SP) to minimize the risk of devastating cord injury while awaiting definitive management. This study examines the incidence of pneumonia (PNA), urinary tract infection (UTI), deep vein thrombosis (DVT), or pulmonary embolism (PE) in this population. STUDY DESIGN: From 2014 to 2016, 344 patients aged 18 and older with spinal column injuries were identified in a prospectively-collected registry at an urban, level 1 trauma center. After exclusion criteria, 330 patients were reviewed and the following were analyzed: demographics, duration of SP, time to intervention, and rates of PNA, UTI, and DVT or PE. Those patients kept in SP for ≤ 72 h ("prolonged") were compared to patients maintained in SP for > 72 h ("early"). RESULTS: Mean age was 54.6 years (SD, 21.7), median Injury Severity Score (ISS) 10 (IQR, 5-17). The median SP was 4.0 (IQR, 3.0-6.0) days. Fifty-eight (17.6%) patients underwent fixation and 170 (51.5%) received a brace. 102 (30.9%) patients initially awaiting a brace were cleared after MRI. 93 (28.2) patients suffered one of the tracked complications; 51 (15.5%) developed PNA, 35 (10.6%) UTI, 23 (7.0%) DVT, and 5 (1.5%) PE. Rate of overall complications between patients with SP ≤ 72 h versus patients with SP > 72 h was statistically significant (20.5% vs 34.6%, p = 0.005) as was the incidence of UTI (14.5 vs 6.0, p = 0.012). CONCLUSION: Prolonged SP (>72 h) is associated with increased rates of immobility-associated morbidities. Focus should be on prompt, definitive care and early mobilization. LEVEL OF EVIDENCE: III Retrospective review of prospectively-collected data.