Operative Candidates Research Articles

Penetrating brain injury caused by tired bullet: First report from Somalia.

Brain injuries caused by a tired bullet can range from headaches to severe brain injury and death. The question which poses a dilemma is whether extraction of retained bullets could decrease the late complications. This study aims to investigate the radiological findings, the neurological status of the patients, and different modalities of management for craniocerebral tired bullet injury. This study retrospectively reviewed 21 patients with a tired bullet injury to the brain who were admitted into our hospital over five years. All patients were assessed for the Glasgow outcome scale as outpatients. Of the 21 patients in the study, 11 (52.3%) were males, and 10 (47.6%) were females. The most common entry point of the bullet was frontal in 8 (38.0%) patients, followed by parietal in 7 (33.3%), and orbital in 5 (23.8%). The mortality rate was 23.8% (n=5 patients). Bad outcomes were documented in patients with low GCS, with all patients who died having a GCS of (3-8). Bullet retrieval was performed for 7 of 21 patients, while all patients who were not candidates for emergency operation underwent local wound debridement. The GOS score was good [4 and 5] in 71.4% (15 of 21 patients). This study revealed that two-thirds of patients with tired bullet injury underwent conservative treatment with an excellent long-term outcome, particularly for patients with high GCS on admission. The mortality rate was high among children under 15 years and those with a GCS of 3-8.

PSUN11 Outcomes of Nonselective or Selective Alpha-Adrenergic Antagonist for Preoperative Management of Intra-adrenal Pheochromocytoma

Abstract Background Pheochromocytoma is a rare neoplasm of the adrenal medulla that leads to catecholamine excess. Adrenalectomy is the standard management for operative candidates. Preoperative alpha-adrenergic antagonism has been traditionally performed with the non-selective irreversible agent phenoxybenzamine. Recently, use of this agent has been limited due to availability and cost. We sought to determine whether type of preoperative antihypertensive management with nonselective alpha-adrenergic antagonist or selective alpha-1 antagonist was associated with differences in patient outcomes for those undergoing adrenalectomy. Methods We performed a retrospective review of adult patients at a single institution undergoing index adrenalectomy for initial diagnosis of intra-adrenal pheochromocytoma from 2012 through 2021. Exclusion criteria were prior adrenalectomy and extra-adrenal pheochromocytoma or paraganglioma. Clinical and demographic factors were assessed. Our primary outcome was intraoperative hemodynamic stability, secondary outcomes were postoperative hemodynamic instability, and surgical complications. Data were analyzed using Chi-squared, Fisher's exact and Mann Whitney U tests. Results During the study period, 38 patients underwent index adrenalectomy for initial diagnosis of intra-adrenal pheochromocytoma. Patient age was a mean of 57.8 years (SD 13.6) with 14 male (37%) and 34 (90%) white. On preoperative cross-sectional imaging, the mean tumor size was 3.9cm (IQR 2.5–5.2) with 15 (40%) left sided, 21 (58%) right sided and 1 (3%) bilateral with 32 (87%) undergoing minimally invasive laparoscopic or robotic assisted adrenalectomy. The mean pre-contrast density on computed tomography imaging was 35.4 Hounsfield units (SD 15). Preoperative plasma metanephrines were mean 0.65 (SD 6.7), plasma normetanephrines 11.1 (SD 14.3). For preoperative pharmacologic therapy, 16 (42%) were on phenoxybenzamine, 21 (55%) selective alpha-1 antagonist, and 1 (3%) patient on both who was excluded from comparative analysis. Nine patients overall (24%) had preoperative hypertensive crisis with no difference between the groups. There was no difference between the groups for intraoperative hemodynamic instability with 6 (38%) in the phenoxybenzamine group and 10 (48%) in the selective alpha blockade group (p = 0.74) or postoperative hemodynamic instability with 5 (31%) compared with 9 (45%) respectively (p = 0.50). Groups were also similar with regard to age, sex, body mass index, comorbidities, preoperative catecholamine levels, American Society of Anesthesiologists Physical Status classification, minimally invasive or open surgery, tumor size, estimated surgical blood loss, and postoperative complications. Follow up duration was longer for the phenoxybenzamine group at 55 months (SD 35) compared with 21 months (SD 25) for the selective alpha blockade group (p = 0.003). Conclusions Use of preoperative alpha adrenergic antagonism selective alpha-1 antagonists showed similar outcomes intraoperative and postoperatively compared with irreversible nonselective alpha-adrenergic antagonists in this cohort. Use of selective alpha-1 antagonists should be considered when nonselective agents are not accessible. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Factors associated with successful median arcuate ligament release in an international, multi-institutional cohort

ObjectivePrior research on median arcuate ligament syndrome has been limited to institutional case series, making the optimal approach to median arcuate ligament release (MALR) and resulting outcomes unclear. In the present study, we compared the outcomes of different approaches to MALR and determined the predictors of long-term treatment failure. MethodsThe Vascular Low Frequency Disease Consortium is an international, multi-institutional research consortium. Data on open, laparoscopic, and robotic MALR performed from 2000 to 2020 were gathered. The primary outcome was treatment failure, defined as no improvement in median arcuate ligament syndrome symptoms after MALR or symptom recurrence between MALR and the last clinical follow-up. ResultsFor 516 patients treated at 24 institutions, open, laparoscopic, and robotic MALR had been performed in 227 (44.0%), 235 (45.5%), and 54 (10.5%) patients, respectively. Perioperative complications (ileus, cardiac, and wound complications; readmissions; unplanned procedures) occurred in 19.2% (open, 30.0%; laparoscopic, 8.9%; robotic, 18.5%; P < .001). The median follow-up was 1.59 years (interquartile range, 0.38-4.35 years). For the 488 patients with follow-up data available, 287 (58.8%) had had full relief, 119 (24.4%) had had partial relief, and 82 (16.8%) had derived no benefit from MALR. The 1- and 3-year freedom from treatment failure for the overall cohort was 63.8% (95% confidence interval [CI], 59.0%-68.3%) and 51.9% (95% CI, 46.1%-57.3%), respectively. The factors associated with an increased hazard of treatment failure on multivariable analysis included robotic MALR (hazard ratio [HR], 1.73; 95% CI, 1.16-2.59; P = .007), a history of gastroparesis (HR, 1.83; 95% CI, 1.09-3.09; P = .023), abdominal cancer (HR, 10.3; 95% CI, 3.06-34.6; P < .001), dysphagia and/or odynophagia (HR, 2.44; 95% CI, 1.27-4.69; P = .008), no relief from a celiac plexus block (HR, 2.18; 95% CI, 1.00-4.72; P = .049), and an increasing number of preoperative pain locations (HR, 1.12 per location; 95% CI, 1.00-1.25; P = .042). The factors associated with a lower hazard included increasing age (HR, 0.99 per increasing year; 95% CI, 0.98-1.0; P = .012) and an increasing number of preoperative diagnostic gastrointestinal studies (HR, 0.84 per study; 95% CI, 0.74-0.96; P = .012) Open and laparoscopic MALR resulted in similar long-term freedom from treatment failure. No radiographic parameters were associated with differences in treatment failure. ConclusionsNo difference was found in long-term failure after open vs laparoscopic MALR; however, open release was associated with higher perioperative morbidity. These results support the use of a preoperative celiac plexus block to aid in patient selection. Operative candidates for MALR should be counseled regarding the factors associated with treatment failure and the relatively high overall rate of treatment failure.

Dynamical Behavior of Two Interacting Double Quantum Dots in 2D Materials for Feasibility of Controlled-NOT Operation.

Two interacting double quantum dots (DQDs) can be suitable candidates for operation in the applications of quantum information processing and computation. In this work, DQDs are modeled by the heterostructure of two-dimensional (2D) MoS2 having 1T-phase embedded in 2H-phase with the aim to investigate the feasibility of controlled-NOT (CNOT) gate operation with the Coulomb interaction. The Hamiltonian of the system is constructed by two models, namely the 2D electronic potential model and the matrix model whose matrix elements are computed from the approximated two-level systems interaction. The dynamics of states are carried out by the Crank–Nicolson method in the potential model and by the fourth order Runge–Kutta method in the matrix model. Model parameters are analyzed to optimize the CNOT operation feasibility and fidelity, and investigate the behaviors of DQDs in different regimes. Results from both models are in excellent agreement, indicating that the constructed matrix model can be used to simulate dynamical behaviors of two interacting DQDs with lower computational resources. For CNOT operation, the two DQD systems with the Coulomb interaction are feasible, though optimization of engineering parameters is needed to achieve optimal fidelity.

Doped Barium Niobate Perovskite Based Materials for High-Temperature Electrolyzer Application and Efficient Methane Conversion

Perovskite materials have helped make notable advances in many applications over the last few decades. Specifically, in high temperature electrochemical technologies such as solid oxide fuel cells (SOFC) and electrolyzers where perovskite-based electrolyte and electrode materials are playing pivotal roles. However, high temperature operation poses significant challenges in both fabrication and durable operation that is further complicated by the operating environment. For example, an electrolyte in a SOFC faces a highly oxidizing environment on the cathode while highly reducing environment on the anode and hence should possess chemical stability under these operating conditions and lifetime requirements for energy conversion technologies often times exceed 10 years of usage with no more than 20% degradation.[1]. Electrochemical oxidative coupling of methane (E-OCM) to ethylene process faces further problems associated with coke and carbonate formation along with the over oxidation of CH4 that invariably leads to CO and CO2. Here we present exciting class of barium niobate perovskites where different cations such as Mg, Ca, Y, and Fe on the niobium site was used for doping and evaluated for E-OCM application. The results are compared with another perovskite material Sr2Fe1.5Mo0.5O6- d (SFMO) that showed good catalytic activity but poor chemical stability. [2][3] Prepared perovskite material was analyzed by XPS, TGA, TPR, SEM, and TEM methodologies towards their chemical stability. Electrochemical properties were evaluated in a home-made setup using different electrolyte materials in the temperature range of 700°C to 900°C by methods such as cyclic voltammetry, impedance spectroscopy, and chronoamperometry. Electrochemical measurements coupled with continuous mass spectra analysis provided valuable insights between product distribution and applied potential. Our results demonstrate doped barium niobates as a promising candidate for stable operation in high temperature electrochemical applications.

Hybrid and endovascular approaches to the aortic arch.

The gold standard treatment for aneurysms and dissections involving the aortic arch remains open total arch replacement. High-risk operative candidates may benefit from hybrid or completely endovascular techniques to reduce the risk of perioperative mortality and morbidity. Numerous endografts are available for investigational use in the aortic arch as part of investigational device exemption (IDE) programs. Some are fenestrated or scalloped, whereas others are branched, ranging from single branch to triple branch stent-grafts. Initial results for completely endovascular repair of the aortic arch are encouraging. Current data estimates that rates of successful deployment of arch endografts ranges from 84.2% to 100%, whereas operative mortality may be as high as 13.2%, with stroke rates being as high as 20% and spinal cord ischemia being as high as 3.1%. More data are necessary to compare hybrid and endovascular stent-grafting of the aortic arch to conventional open total arch replacement. Longitudinal follow-up is also lacking, which will determine the long-term durability of endografts in the aortic arch. However, endovascular repair represents an important opportunity for improving outcomes in high-risk patients with complex aneurysms and dissections of the aortic arch.

P36. Multilevel posterior cervical foraminotomy associated with increased perioperative infection rates relative to anterior cervical discectomy with fusion and cervical disc arthroplasty

P36. Multilevel posterior cervical foraminotomy associated with increased perioperative infection rates relative to anterior cervical discectomy with fusion and cervical disc arthroplasty

Reintubation After Lung Cancer Resection: Development and External Validation of a Predictive Score

BackgroundReintubation after lung cancer resection is an important quality metric because of increased disability, mortality and cost. However, no validated predictive instrument is in use to reduce reintubation after lung resection. This study aimed to create and validate the PRediction Of REintubation After Lung cancer resection (PROREAL) score. MethodsThe study analyzed lung resection cases from 2 university hospitals. The primary end point was reintubation within 7 days after surgery. Predictors were selected through backward stepwise logistic regression and bootstrap resampling. The investigators used reclassification and receiver-operating characteristic (ROC) curve analyses to assess score performance and compare it with an established score for all surgical patients (Score for Prediction of Postoperative Respiratory Complications [SPORC]). ResultsThe study included 2672 patients who underwent resection for lung cancer (1754, development cohort; 918, validation cohort) between 2008 and 2020, of whom 71 (2.7%) were reintubated within 7 days after surgery. Identified score variables were surgical extent and approach, American Society of Anesthesiologists physical status, heart failure, renal disease, and diffusing capacity of the lung for carbon monoxide. The score achieved excellent discrimination in the development cohort (ROC AUC, 0.90; 95% CI, 0.87-0.94) and good discrimination in the validation cohort (ROC AUC, 0.74, 95% CI; 0.66-0.82), thus outperforming the SPORC in both cohorts (P < .001 and P = .018, respectively; validation cohort net reclassification improvement, 0.39; 95% CI, 0.18-0.60; P = .001). The score cutoff of ≥5 yielded a sensitivity of 88% (95% CI, 72-95) and a specificity of 81% (95% CI,79-83) in the development cohort. ConclusionsA simple score (PROREAL) specific to lung cancer predicts postoperative reintubation more accurately than the nonspecific SPORC score. Operative candidates at risk may be identified for preventive intervention or alternative oncologic therapy.

Miniaturized bandwidth reconfigurable microwave bandpass filter

PurposeModern wireless communications need novel microwave components that can be effectively used for high data rate and low-power applications. The operating environment decides the severity of the noise coupled to the transceiver system from the ambient environment. In a deep fading environment, narrowband systems fail where the wideband systems come for rescue. Thus, the microwave components are ought to switch between the narrowband and wideband states. This paper aims to study the design of a bandpass filter to meet the requirements by appropriately switching between the dual narrowband frequencies and single ultra-wideband frequency band.Design/methodology/approachThe design and implementation of a compact microwave filter with reconfigurable bandwidth characteristics are presented in this paper. The proposed filter is constructed using a hexagonal ring with shorted perturbation along one corner. The filter is capacitively coupled to the external excitation source. External stubs are connected to the corners of the hexagonal resonator to obtain dual passband characteristics centred at 2.1 and 4.5 GHz. The external stubs are configured to achieve bandwidth reconfigurable characteristics. PIN diodes are used with a suitable biasing network to obtain reconfiguration. In the reconfigured state, the proposed two-port filter offers a continuous bandwidth from 2.1 to 5.9 GHz. The roll-off rate along the band edges is improved by increasing the order of the filter.FindingsThe proposed filter operates in two states. In state 1, the filter operates with dual frequencies centred around 2 and 4.5 GHz with insertion loss less than <1 dB and return loss greater than 13 dB with a peak return loss of 21 and 31 dB at 2.1 and 2.15 GHz, respectively. In state 2, the filter operates from 2.1 to 5.9 GHz with insertion loss less than 1 dB and return loss greater than 12 dB. The filter exhibits four-pole characteristics with a peak return loss greater than 22 dB. Thus, the fractional bandwidth of the proposed filter is 17% and 16% in state 1, whereas the fractional bandwidth is 95% in state 2.Originality/valueThe proposed filter is the first of its kind to simultaneously offer miniaturization and bandwidth reconfiguration. The proposed second-order filter has two-pole characteristics in the narrowband state, whereas four-pole characteristics are realized in the wideband state. The growing interest in 4G and 5G wireless communications makes the proposed filter a suitable candidate for operation in the rich scattering environment.

Ultrasound assisted solid phase extraction of methylene blue dye by MgSiO3 nanoparticles through central composite design

ABSTRACT Current study is based on the synthesis and characterisation of MgSiO3 nanoparticles (MgSiO3 NPs) and its application for ultrasound-assisted solid-phase extraction (UASPE) of methylene blue (MB) dye from water samples using UV-Vis spectrophotometry. The prepared MgSiO3 NPs were fully identified and characterised by different techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDS). The prepared nano sorbent had spherical shape with size diameter of 20 nm. Central composite design (CCD) optimisation approach as versatile tool was used for investigation and optimisation of the effective parameters. Using CCD method, the optimised conditions were achieved to be pH of 7.0, sorbent dosage of 29.80 mg, ultrasonic time of 10.34 min, and temperature of 25°C at 500 µl of dimethylformamide eluent using Triton X-100 surfactant. Under the optimised conditions, the proposed method is applicable for wide linear range with detection limit of 0.084 mg L−1, limit of quantification of 0.28 mg L−1. The prepared MgSiO3 NPs have exceptional properties in terms of porous and sheets structure and also high adsorption capacity. In addition, the applied method showed satisfactory figure of merits in terms of pre-concentration factor of 10, which make candidate the applied method and nano sorbent as an operative and ideal candidate for pre-concentration and determination trace level of MB from water samples.

Portal vein stenting in the management of duodenal varices due to malignant obstruction: A case report and literature review.

Introduction and importanceEctopic varices of the small bowel are a rare complication of portal hypertension. There are various aetiologies that can cause portal vein hypertension such as portal vein obstruction. Each of these pathologies has their own management strategies. Currently, there is a paucity of literature demonstrating the best management for patients with malignant portal vein obstruction leading to these varices.Case presentationThis report presents a case of a 66-year-old female who presented with recurrent per-rectal bleeding. Computed tomography angiography diagnosed duodenal varices in the context of malignant obstruction of the portal vein. Due to being a poor operative candidate, she underwent trans-hepatic portal vein stenting leading to resolution of her symptoms.Clinical discussionTo date, the management of portal vein obstruction due to various aetiologies has only been reported in case reports with no significant large-scale studies providing recommendations on the most appropriate treatment. This case demonstrates the role of palliative stenting for patients with portal hypertension due to malignant portal vein obstruction.ConclusionDuodenal varices are a rare complication of portal vein obstruction. This article contributes to the literature by demonstrating that patients with complications associated with portal vein obstruction can benefit from stenting. For those with malignant obstruction, palliative stenting serves as an important therapeutic option.

The use of three-dimensional imaging for R0 resection of a left upper lobe adenocarcinoma after coronary artery bypass surgery.

The use of three-dimensional imaging for R0 resection of a left upper lobe adenocarcinoma after coronary artery bypass surgery.

Endoscopic nodal staging in oligometastatic non-small cell lung cancer (NSCLC) being treated with stereotactic ablative radiotherapy (ENDO-SABR)

BackgroundResearch in treatment of non-small cell lung cancer (NSCLC) has shown promising results with stereotactic ablative radiotherapy (SABR) of oligometastatic disease, wherein distant disease may be limited to one or a few distant organs by host factors. Traditionally, PET/CT has been used in detecting metastatic disease and avoiding futile surgical intervention, however, sensitivity and specificity is limited to only 81 and 79%, respectively. Mediastinal staging still identifies occult nodal disease in up to 20% of NSCLC patients initially thought to be operative candidates. Endobronchial ultrasound and transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive tool for the staging and diagnosis of thoracic malignancy. When EBUS is combined with endoscopic ultrasound using the same bronchoscope (EUS-B), the diagnostic sensitivity and negative predictive value increase to 84 and 97%, respectively. Endoscopic staging in patients with advanced disease has never been studied, but may inform treatment if a curative SABR approach is being taken.MethodsThis is a multi-centre, prospective, cohort study with two-stage design. In the first stage, 10 patients with oligometastatic NSCLC (lung tumour ± hilar/mediastinal lymphadenopathy) with up to 5 synchronous metastases will be enrolled An additional 19 patients will be enrolled in the second stage if rate of treatment change is greater than 10% in the first stage. Patients will be subject to EBUS or combined modality EBUS/EUS-B to assess bilateral lymph node stations using a N3 to N2 to N1 progression. Primary endpoint is defined as the rate of change to treatment plan including change from SABR to conventional dose radiation, change in mediastinal radiation field, and change from curative to palliative intent treatment.DiscussionIf a curative approach with SABR for oligometastatic disease is being explored, invasive mediastinal staging may guide treatment and prognosis. This study will provide insight into the use of endoscopic mediastinal staging in determining changes in treatment plan of NSCLC. Results will inform the design of future phase II trials.Trial registrationClinicaltrials.gov identifier NCT04852588. Date of registration: April 19, 2021. Protocol version: 1.1 on December 9, 2021.

Treatment Patterns in Women Age 80 and Over With DCIS: A Report From the National Cancer Database

BackgroundDespite an aging population, there are no established treatment guidelines for women with ductal carcinoma in situ (DCIS) age ≥80. Here we describe national treatment patterns and survival outcomes in older women with DCIS. Patients and MethodsWomen age ≥80 diagnosed with DCIS from 2005 to 2014 were identified using the National Cancer Database. χ2, Fisher's exact test, and logistic regression models were used to identify factors influencing receipt of breast surgery, and Kaplan-Meier method and Cox proportional hazard models were used to evaluate overall survival (OS). ResultsA total of 6,070 women with DCIS met inclusion criteria, of which the majority (98%) received surgery. Receipt of surgery was independently associated with age <90. OS was higher for those who received surgery compared to those who did not (HR 2.2 [1.72-2.83] P < .001). ConclusionThe vast majority of patients age ≥80 with DCIS in the National Cancer Database received primary surgical management, which was associated with a significant OS benefit. Considering comorbidities and patient fitness, surgical resection should be considered for all patients age ≥80 who are suitable operative candidates.

Dealing with a Pediatric Posterior Fossa Tumor after COVID-19 Infection: Report of One Case

Plain Language SummaryHaving the issue of coronavirus disease 2019 (COVID-19) in mind, there is always a dilemma surrounding elective and non-urgent neurosurgical operations. The unanswered question is regarding whether there is any post-COVID-19 complications that hinder a patient from becoming a candidate for a neurosurgical operation. If that is the case, what should we do?In the present article, we report our single-center experience with an unusual bleeding during the operation of a huge cerebellar tumor in a girl previously infected with COVID-19. In the end, we recommend our experience to our colleagues. Abstract There are still some conditions that pediatric neurosurgeons may face in the context of coronavirus disease 2019 (COVID-19) which have not been fully addressed so far. Authors have postulated an ongoing inflammatory myocardial status in a significant proportion of patients who have recovered from COVID-19. We report our experience with a 10-month-old girl who had recovered form COVID-19 and had a case of fourth-ventricle mass in the midline of the posterior fossa. She was scheduled for microneurosurgical resection of the mass following the insertion of a ventriculoperitoneal shunt. There were no significant issues regarding the induction of anesthesia. A midline suboccipital approach was chosen, and the patient was fully prepared and draped. Suboccipital soft tissues and muscles were dissected layer by layer through the midline avascular line. A marked gush of blood off the midline was observed during the opening in Y of the dura mater. Then, we started to approach the occipital sinus. However, there was an unusual loss of ∼ 200 mL of blood lost from this area. Despite the proper packed-cell transfusion, the patient developed bradycardia and a sudden rhythm of asystole. The cardiopulmonary cerebral resuscitation (CPCR) was initiated immediately. Despite the maximal effort, the heart rate did not change and remained asystole. We recommend that pediatric neurosurgeons postpone the procedures to be performed in patients who have recovered from COVID-19 for more than one month after a thorough preoperative cardiac evaluation has been performed.

Assessing the Role of Operative Intervention in Elderly Patients With Nonfunctional Pancreatic Neuroendocrine Neoplasms.

Resection of locoregional pancreatic neuroendocrine neoplasms (PanNENs) is typically recommended, but there is a paucity of data on the management of elderly patients. The National Cancer Database (2004-2016) was queried for patients 80 years or older with localized PanNENs. Patients were grouped as nonoperative or operative management. Postoperative outcomes and survival were compared. In total, 591 patients were included: 202 underwent resection, and 389 did not. Increasing age and pancreatic head tumors were associated with lower likelihood of resection. The overall 90-day mortality rate was 6.4%, which was higher for pancreatoduodenectomy than distal pancreatectomy (13.6% vs 5.1%, respectively). Operatively managed patients had longer median survival (80.8 vs 45.0 months, P < 0.001), and this association was independent of tumor location. On multivariable Cox regression, resection remained associated with longer survival (hazard ratio, 0.69; 95% confidence interval, 0.50-0.95). Among operatively managed patients, age and tumor location were not associated with survival; however, greater comorbidity and high-risk tumor-specific features were associated with worse survival. Resection of nonfunctional PanNENs in elderly patients is associated with improved survival compared with nonoperative management. Resection could be considered in appropriate operative candidates, regardless of tumor location, but the perioperative mortality rate must be considered.

Improving Surgical Triage in Spine Clinic: Predicting Likelihood of Surgery Using Machine Learning

Correctly triaging patients to a surgeon or a nonoperative provider is an important part of the referral process. Clinics typically triage new patients based on simple intake questions. This is time-consuming and does not incorporate objective data. Our goal was to use machine learning to more accurately screen surgical candidates seen in a spine clinic. Using questionnaire data and magnetic resonance imaging reports, a set of artificial neural networks was trained to predict whether a patient would be recommended for spine surgery. Questionnaire responses included demographics, chief complaint, and pain characteristics. The primary end point was the surgeon's determination of whether a patient was an operative candidate. Model accuracy in predicting this end point was assessed using a separate subset of patients. The retrospective dataset included 1663 patients in cervical and lumbar cohorts. Questionnaire data were available for all participants, and magnetic resonance imaging reports were available for 242 patients. Within 6 months of initial evaluation, 717 (43.1%) patients were deemed surgical candidates by the surgeon. Our models predicted surgeons' recommendations with area under the curve scores of 0.686 for lumbar (positive predictive value 66%, negative predictive value 80%) and 0.821 for cervical (positive predictive value 83%, negative predictive value 85%) patients. Our models used patient data to accurately predict whether patients will receive a surgical recommendation. The high negative predictive value demonstrates that this approach can reduce the burden of nonsurgical patients in surgery clinic without losing many surgical candidates. This could reduce unnecessary visits for patients, increase the proportion of operative candidates seen by surgeons, and improve quality of patient care.

Spectral dependence of principal axes in anti-resonant hollow-core fibers with different numbers of capillaries.

We report on measurements highlighting the spectral dependence of the principal axes' angular orientation that is present within three hollow-core fibers samples of various geometries. Hollow-core anti-resonant fibers (ARFs) with six, five, and four capillaries are investigated in several transmission windows. It is shown that the six-capillary fiber structure demonstrates a much smaller shift in the principal axes' orientation, in comparison with five- and four-capillary structures. The four-capillary structure has a 90° shift of its principal axes' orientation inside even- and odd-numbered transmission windows. These results corroborate the suggestion that the six-capillary ARF structure is a great candidate for polarization-maintaining operation over a wide spectral bandwidth.

Surgical Treatment of Patients with Poorly Differentiated Pancreatic Neuroendocrine Carcinoma: An NCDB Analysis.

Consensus guidelines discourage resection of poorly differentiated pancreatic neuroendocrine carcinoma (panNEC) given its association with poor long-term survival. This study assessed treatment patterns and outcomes for this rare malignancy using the National Cancer Database (NCDB). Patients with non-functional pancreatic neuroendocrine tumors in the NCDB (2004-2016) were categorized based on pathologic differentiation. Logistic and Cox proportional hazard regressions identified associations with resection and overall survival (OS). Survival was compared using Kaplan-Meier and log-rank tests. Most patients (83%) in the cohort of 8560 patients had well-differentiated tumors (panNET). The median OS was 47 months (panNET, 63 months vs panNEC, 17 months; p < 0.001). Surgery was less likely for older patients (odds ratio [OR], 0.97), patients with panNEC (OR, 0.27), and patients with metastasis at diagnosis (OR, 0.08) (all p < 0.001). After propensity score-matching of these factors, surgical resection was associated with longer OS (82 vs 29 months; p < 0.001) and a decreased hazard of mortality (hazard ratio [HR], 0.37; p < 0.001). Surgery remained associated with longer OS when stratified by differentiation (98 vs 41 months for patients with panNET and 36 vs 8 months for patients with panNEC). Overall survival did not differ between patients with panNEC who underwent surgery and patients with panNET who did not (both 39 months; p = 0.294). Poorly differentiated panNEC exhibits poorer survival than well-differentiated panNET. In the current cohort, surgical resection was strongly and independently associated with improved OS, suggesting that patients with panNEC who are suitable operative candidates should be considered for multimodality therapy, including surgery.

Properties of Microconcrete Produced with Fly Ash and Ultrafine Silica

Abstract Microconcrete is an important subclass of regular concrete that lacks the coarse aggregate commonly found in standard concrete. This makes it a good candidate for certain casting operations, such as densely reinforced elements. Microconcrete also tends to have better workability and smoother flow in formwork elements than regular concrete. However, one of humanity’s current problems is air pollution caused by chemical, physical, or biological agents with harmful effects on the environment. Carbon dioxide (CO2) resulting from cement production is a major atmospheric pollutant. To align with sustainable development standards, the construction industry must seek alternative materials that are more environmentally friendly. This article presents a comparison of the properties of regular microconcrete and microconcrete with additives such as fly ash and ultrafine silica. This topic is important because environmental issues are becoming more pressing. The results show that using waste products as additives in microconcrete can provide a sustainable solution for reducing carbon dioxide emissions and environmental impact. Although lower strengths were obtained compared to traditional concrete, microconcrete with waste products can be used in various applications, such as the production of prefabricated construction elements or the rehabilitation of existing structures. Additionally, it can be used in the construction of paving stones, sidewalks, or industrial floors, contributing to reducing pollution and environmental impact.