Explore the vast range of titles available.

Polyolefins have a multitude of uses across packaging, automotive and construction sectors. Their resistance to degradation during reprocessing enables recyclability, but variability in recycled polymer feedstocks renders it difficult to assure their manufacturing suitability. The lack of quality control methods has disabled circular economy pathways; product failure is costly, wasteful and time-intensive. Using rheology-simulated and extrusion-based recycling experiments, we explore the degradation pathways of high-density polyethylene (HDPE). Chain scission dominates during the initial degradation of HDPE, and increasing exposure to O 2 shifts the dominant mechanism to long-chain branching. Importantly, extending this method to post-consumer recyclate (PCR), the results show potential as a methodology to assess recyclate quality to enable a circular plastics economy. In this study, we establish the validity of this rheology simulation to define a characteristic degradation parameter, relating it to the structural evolution under different environments defined for virgin HDPE and post-consumer recyclate (PCR). Polyolefins are used across packaging, automotive and construction but variability in recycled polymer feedstocks renders it difficult to assure a consistent manufacturing quality. Here, the authors use rheology-simulated and extrusion-based recycling experiments to explore the degradation pathways of high-density polyethylene and present a rheology-based method to assess the quality of the recycled material.

This report presents a case of acquired tracheal stenosis in a pediatric patient without a history of prolonged intubation. A 14‐year‐old female presented with a chief complaint of biphasic stridor and a medical history remarkable for bulimia nervosa and one year of self‐induced vomiting. Endoscopic evaluation revealed Grade three tracheal stenosis. Lab work was unrevealing for acute inflammatory process nor vasculitis. Pathology was unremarkable. The patient tolerated primary dilation and second look did not reveal further stenosis. Her extensive workup failed to reveal an alternative etiology with a working hypothesis that the stenosis was a result of chronic retching due to bulimia.

Background and AimsHepatic encephalopathy (HE) is a common cause of hospitalizations and readmissions for patients with decompensated cirrhosis. In this study, we proposed to investigate recent trends in in-hospital mortality and utilization for patients with cirrhosis and HE and to explore the effect of various sociodemographic, hospital, and clinical factors on mortality.MethodsWe performed an observational study using serial cross-sectional data from the 2009–2013 National Inpatient Sample to examine hospitalizations of patients with cirrhosis and HE. We collected data on in-hospital mortality, length of stay, and total hospital costs. We used negative binomial regression and logistic regression to investigate trends in utilization and multilevel modeling to examine the association between sociodemographic, hospital, and clinical factors and in-hospital mortality. ResultsThe annual total number of hospitalizations from HE has steadily risen from 75,475 in 2009 to 106,915 in 2013 (P < 0.001). Annual in-hospital mortality (11.9–10.2%, P < 0.001) and length of stay (7.5–7.1 days, P = 0.015) have significantly decreased over this timeframe. The presence of septicemia, GI bleeding, and being uninsured were associated with 29.6%, 16.7%, and 15.7% of in-hospital death, respectively. Patients hospitalized in the South, Medicare beneficiaries, and patients hospitalized in the Midwest had a 9.8%, 9.2%, and 8.9% chance of dying in the hospital. ConclusionThe number of hospitalizations from HE has increased while in-hospital mortality has concomitantly decreased from 2009 to 2013. Both traditional risk factors (sepsis and GI bleeding) strongly influence the probability of in-hospital death. However, disparities in mortality by sociodemographic factors (insurance status and geography) also exist.

Purpose Primary treatment of spinal ependymomas involves surgical resection, however recurrence ranges between 50 and 70%. While the association of survival outcomes with lesion extent of resection (EOR) has been studied, existing analyses are limited by small samples and archaic data resulting in an inhomogeneous population. We investigated the relationship between EOR and survival outcomes, chiefly overall survival (OS) and progression-free survival (PFS), in a large contemporary cohort of spinal ependymoma patients. Methods Adult patients diagnosed with a spinal ependymoma from 2006 to 2021 were identified from an institutional registry. Patients undergoing primary surgical resection at our institution, ≥ 1 routine follow-up MRI, and pathologic diagnosis of ependymoma were included. Records were reviewed for demographic information, EOR, lesion characteristics, and pre-/post-operative neurologic symptoms. EOR was divided into 2 classifications: gross total resection (GTR) and subtotal resection (STR). Log-rank test was used to compare OS and PFS between patient groups. Results Sixty-nine patients satisfied inclusion criteria, with 79.7% benefitting from GTR. The population was 56.2% male with average age of 45.7 years, and median follow-up duration of 58 months. Cox multivariate model demonstrated significant improvement in PFS when a GTR was attained ( p  <.001). Independently ambulatory patients prior to surgery had superior PFS ( p  <.001) and OS ( p  =.05). In univariate analyses, patients with a syrinx had improved PFS ( p  =.03) and were more likely to benefit from GTR ( p  =.01). Alternatively, OS was not affected by EOR ( p  =.78). Conclusions In this large, contemporary series of adult spinal ependymoma patients, we demonstrated improvements in PFS when GTR was achieved.

Abstract BACKGROUND Multimodal analgesia regimens have been suggested to improve pain control and reduce opioid consumption after surgery. OBJECTIVE To institutionally implement an evidence-based quality improvement initiative to standardize and optimize pain treatment following neurosurgical procedures. Our goal was to objectively evaluate efficacy of this multimodal protocol. METHODS A retrospective cohort analysis of pain-related outcomes after posterior lumbar fusion procedures was performed. We compared patients treated in the 6 mo preceding (PRE) and 6 mo following (POST) protocol execution. RESULTS A total of 102 PRE and 118 POST patients were included. The cohorts were well-matched regarding sex, age, surgical duration, number of segments fused, preoperative opioid consumption, and baseline physical status (all P > .05). Average patient-reported numerical rating scale pain scores significantly improved in the first 24 hr postoperatively (5.6 vs 4.5, P < .001) and 24 to 72 hr postoperatively (4.7 vs 3.4, P < .001), PRE vs POST, respectively. Maximum pain scores and time to achieving appropriate pain control also significantly improved during these same intervals (all P < .05). A concomitant decrease in opioid consumption during the first 72 hr was seen (110 vs 71 morphine milligram equivalents, P = .02). There was an observed reduction in opioid-related adverse events per patient (1.31 vs 0.83, P < .001) and hospital length of stay (4.6 vs 3.9 days, P = .03) after implementation of the protocol. CONCLUSION Implementation of an evidence-based, multimodal analgesia protocol improved postoperative outcomes, including pain scores, opioid consumption, and length of hospital stay, after posterior lumbar spinal fusion.

To assess the utility of apparent diffusion coefficient (ADC) maps for the assessment of patients with advanced degenerative lumbar spine disease and describe characteristic features of ADC maps in various degenerative lumbar spinal conditions. T1-weighted, T2-weighted and diffusion weighted (DWI) MR images of 100 consecutive patients admitted to the spinal surgery service were assessed. ADC maps were generated from DWI images using Osyrix software. The ADC values and characteristic ADC maps were assessed in the regions of interest over the different pathological entities of the lumbar spine. The study included 452 lumbar vertebral segments available for analysis of ADCs. Characteristic ADC map features were identified for protrusion, extrusion and sequester types of lumbar disk herniations, spondylolisthesis, reactive Modic endplate changes, Pfirrmann grades of IVD degeneration, and compromised spinal nerves. Compromised nerve roots had significantly higher mean ADC values than adjacent (p < 0.001), contralateral (p < 0.001) or adjacent contralateral (p < 0.001) nerve roots. Compared to the normal bone marrow, Modic I changes showed higher ADC values (p = 0.01) and Modic 2 changes showed lower ADC values (p = 0.02) respectively. ADC values correlated with the Pfirrmann grading, however differed from herniated and non-herniated disks of the matched Pfirrmann 3 and 4 grades. Quantitative and qualitative evaluation of ADC mapping may provide additional useful information regarding the fluid dynamics of the degenerated spine and may complement standard MRI imaging protocol for the comprehensive assessment of surgical patients with lumbar spine pathology. ADC maps were advantageous in differentiating reactive bone marrow changes, and more precise assessment of the disk degeneration state. ADC mapping of compressed nerve roots showed promise but requires further investigation on a larger cohort of patients.

BackgroundThe risk of spinal epidural hematoma (SEH) has been described in the literature but the impact in various patient populations has not been assessed in the same study. We identified the risk factors for SEH and calculated the OR for recovery in the pediatric, adult and obstetric (OB) patients based on the degree of neurological deficit before surgery.MethodsAdult non-OB cases were categorized whether they were on anticoagulants or not; SEH was related to neuraxial or pain procedure; or whether there was adherence to the American Society of Regional Anesthesia (ASRA) guidelines. Eligible cases were identified through PubMed and Embase searches in the English literature from 1954 to July 2022.ResultsA total of 940 cases were evaluated. In the pediatric cases, SEH was typically spontaneous, related to coagulopathy or athletic trauma. OB cases were spontaneous or related to neuraxial injections. Among adults on anticoagulant(s), SEH was mostly spontaneous with no related etiology or related to neuraxial procedure. SEH occurred despite adherence to the ASRA guidelines. Among non-OB adults not on anticoagulants, SEH was due to trauma, neuraxial injections, surgery or other causes. Neurological recovery was related to the degree of neurological deficit before surgery.ConclusionsOur data show a preponderance of spontaneous SEH in all patient populations. SEH developed even though the ASRA guidelines were followed, especially in patients on multiple anticoagulants. Patients with less impairment prior to surgery had a higher likelihood of complete recovery, regardless of the interval between surgery and onset of symptoms.

IntroductionAnticipation of patient-specific component sizes prior to total knee arthroplasty (TKA) is essential to avoid excessive cost associated with additional surgical trays and morbidity associated with imperfect sizing. Current methods of size prediction, including templating, are inconsistent and time-consuming. Machine learning (ML) algorithms may allow for accurate TKA component size prediction with the ability to make predictions in real-time.MethodsConsecutive patients receiving primary TKA between 2012 and 2020 from two large tertiary academic and six community hospitals were identified. The primary outcomes were the final femoral and tibial component sizes extracted from automated inventory systems. Five ML algorithms were trained with routinely corrected demographic variables (age, height, weight, body mass index, and sex) using 80% of the study population and internally validated on an independent set of the remaining 20% of patients. Algorithm performance was evaluated through accuracy, mean absolute error (MAE), and root mean-squared error (RMSE).ResultsA total of 17,283 patients that received one of 9 TKA implants from independent manufacturers were included. The SGB model accuracy for predicting ± 4-mm of the true femoral anteroposterior diameter was 83.6% and for ± 1 size of the true femoral component size was 95.0%. The SGB model accuracy for predicting ± 4-mm of the true tibial medial/lateral diameter was 83.0% and for ± 1 size of the true tibial component size was 97.8%. Patient sex was the most influential feature in terms of informing the SGB model predictions for both femoral and tibial component sizing. A TKA implant sizing application was subsequently created.ConclusionNovel machine learning algorithms demonstrated good to excellent performance for predicting TKA component size. Patient sex appears to contribute an important role in predicting TKA size. A web-based real-time prediction application was created capable of integrating patient specific data to predict TKA size, which will require external validation prior to clinical use.