Derivation of the Falls Decision Rule to exclude intracranial bleeding without head CT in older adults who have fallen.

BACKGROUND: Ground-level falls are common among older adults and are the most frequent cause of traumatic intracranial bleeding. The aim of this study was to derive a clinical decision rule that safely excludes clinically important intracranial bleeding in older adults who present to the emergency department after a fall, without the need for a computed tomography (CT) scan of the head. METHODS: This prospective cohort study in 11 emergency departments in Canada and the United States enrolled patients aged 65 years or older who presented after falling from standing on level ground, off a chair or toilet seat, or out of bed. We collected data on 17 potential predictor variables. The primary outcome was the diagnosis of clinically important intracranial bleeding within 42 days of the index emergency department visit. An independent adjudication committee, blinded to baseline data, determined the primary outcome. We derived a clinical decision rule using logistic regression. RESULTS: The cohort included 4308 participants, with a median age of 83 years; 2770 (64%) were female, 1119 (26%) took anticoagulant medication and 1567 (36%) took antiplatelet medication. Of the participants, 139 (3.2%) received a diagnosis of clinically important intracranial bleeding. We developed a decision rule indicating that no head CT is required if there is no history of head injury on falling; no amnesia of the fall; no new abnormality on neurologic examination; and the Clinical Frailty Scale score is less than 5. Rule sensitivity was 98.6% (95% confidence interval [CI] 94.9%-99.6%), specificity was 20.3% (95% CI 19.1%-21.5%) and negative predictive value was 99.8% (95% CI 99.2%-99.9%). INTERPRETATION: We derived a Falls Decision Rule, which requires external validation, followed by clinical impact assessment. Trial registration: ClinicalTrials. gov, no. NCT03745755.

COVID-19, commuter territories and the e-bike boom.

The appearance and integration of e-bikes in public space is a source of much debate worldwide. This paper offers insights to these debates by reflecting on how Deleuze and Guattari's concept of assemblage as territory helps us to understand the uptake of e-bike commuter cycling during the Covid-19 pandemic through empirical material from a study conducted in Sydney, Australia. Here we conceptualise commuter journeys in terms of processes of deterritorialisation and reterritorialisation; experienced through the affective territories generated by e-bikes. The disclosure of commuter cycling sensations generated by the pandemic disruptions to commuter routines provided an important lens through which to understand the uptake of e-bikes. The paper concludes by showing the utility of the concept of territory as a means of theorising changes to everyday mobility practices.

The odontoid-CSVL distance in a global population of asymptomatic volunteers: normative values and implications for spinal coronal alignment.

PURPOSE: In a population of asymptomatic volunteers across 5 countries, we sought to: (a) establish normative values of the Odontoid-Central Sacral Vertical Line (OD-CSVL) across patient factors, and (b) assess correlations of OD-CSVL with other radiographic parameters. METHODS: A prospective, cross-sectional study of asymptomatic adult volunteers, ages 18-80 years, were enrolled across 5 countries (France, Japan, Singapore, Tunisia, United States) forming the Multi-Ethnic Alignment Normative Study (MEANS) cohort. Included volunteers had no known spinal disorder(s), no significant neck/back pain (VAS ≤ 2; ODI ≤ 20), and no significant scoliosis (Cobb ≤ 20°). Radiographic measurements included commonly used coronal alignment parameters (mm) and angles (°). OD-CSVL was defined as the difference between the odontoid plumb line (line from the tip of the odontoid vertically down) and the CSVL (vertical line from the center of the sacrum). Chi-square, student's t tests, Kruskal-Wallis, Wilcoxon rank-sum, linear regression, and Pearson's correlation were used with significance at p < 0.05. RESULTS: 467 volunteers were included with normative OD-CSVL values by age decade, gender, BMI, and country. Mean ± SD OD-CSVL was 8.3 mm ± 6.5 mm and 31 (6.6%) volunteers were almost perfectly aligned (OD-CSVL < 1 mm). A linear relationship was seen between OD-CSVL with both age (p < 0.001) and BMI (p = 0.015). Significant variation was seen between OD-CSVL and 5 different ethnicities (p = 0.004). OD-CSVL correlated best with other coronal radiographic parameters, C7-CSVL (r = 0.743, p < 0.001), OD-knee (r = 0.230, p < 0.001), CAM-knee (r = 0.612, p < 0.001), and regional TL cobb angle (r = 0.4214, p = 0.005). CONCLUSION: Among asymptomatic volunteers, increased OD-CSVL was significantly associated with increased age, increased BMI, and ethnicity, but not gender. OD-CSVL correlated strongest with C7-CSVL, TL cobb angle, OD-knee, and CAM-knee. OD-CSVL. These results support further study of OD-CSVL in symptomatic adult spine deformity patients.

Simplified retrieval method for Edge Illumination X-ray phase contrast imaging allowing multi-modal imaging with fewer input frames.

We present data from an implementation of Edge Illumination (EI) that uses a detector aperture designed for increasing dynamic range, suitable for clinically relevant X-ray energies and demonstrated here using synchrotron radiation. By utilising a sufficiently large crosstalk between pixels, this implementation enables single-scan imaging for phase and absorption, and double-scan for phase, absorption and dark field imaging. The presence of the detector mask enables a direct comparison between conventional EI and beam tracking (BT), which we conduct through Monte Carlo and analytical modelling in the case of a single-scan being used for the retrieval of all three contrasts. In the present case, where the X-ray beam width is comparable to the pixel size, we provide an analysis on best-positioning of the beam on the detector for accurate signal retrieval. Further, we demonstrate an application of this method by distinguishing different concentrations of microbubbles via their dark field signals at high energy using an EI system.

Fast, non-iterative algorithm for quantitative integration of X-ray differential phase-contrast images.

X-ray phase contrast imaging is gaining importance as an imaging tool. However, it is common for X-ray phase detection techniques to be sensitive to the derivatives of the phase. Therefore, the integration of differential phase images is a fundamental step both to access quantitative pixel content and for further analysis such as segmentation. The integration of noisy data leads to artefacts with a severe impact on image quality and on its quantitative content. In this work, an integration method based on the Wiener filter is presented and tested using simulated and real data obtained with the edge illumination differential X-ray phase imaging method. The method is shown to provide high image quality while preserving the quantitative pixel content of the integrated image. In addition, it requires a short computational time making it suitable for large datasets.

A chemotherapy privileging process for advanced practice providers at an academic medical center.

PURPOSE: Nurse practitioners, physician assistants, and pharmacists are advanced practice providers who are highly trained and qualified healthcare professionals that can help support traditional demands on oncologists' increased time in direct patient care. The purpose of this study was to detail and assess the creation of a privileging process for this group of medical professionals within an academic medical center. Obtaining the designation of limited oncology practice provider (LOPP) gives the right to modify chemotherapy orders and to order supportive care medications. METHODS: An interdisciplinary team developed a comprehensive training process inclusive of required educational domains, knowledge goals, and educational activities to become an LOPP. In 2018, five years after the implementation of the privileging process, a survey was distributed to assess perceptions of the training process and integration of LOPPs within oncology practice. RESULTS: Most oncologists noted that working with LOPPs is beneficial to oncology practice (94%) and that they make modifying chemotherapy orders more efficient (87%). Greater than 82% of LOPPs also reported that their privileges streamline the chemotherapy process and make them feel valuable. CONCLUSION: The creation of the LOPP designation is an effective way to integrate nurse practitioners, physician assistants, and pharmacists within oncology practice. The inclusion of a focused privileging process ensures the safety of cancer care provided and has created a streamlined process for chemotherapy modifications and supportive care.

Evaluation of facet joints and segmental motion in patients with different grades of L5/S1 intervertebral disc degeneration: a kinematic MRI study.

PURPOSE: This study aimed to evaluate facet joint parameters and osteoarthritis grades, and segmental angular and translational motions among different grades of L5/S1 intervertebral disc (IVD) degeneration. METHODS: This retrospective study analysed kinematic magnetic resonance imaging (kMRI) images of the lumbar spine of 214 patients with low back pain. Degenerations of the L5/S1 IVDs and facet joints osteoarthritis were assessed using the Pfirrmann and Pathria grading scales, respectively. Facet joint parameters included facet joint angle and facet joint space width. Angular and translation segmental motions were measured using MRI Analyzer software. RESULTS: The mean age of the studied patients was 44.1 ± 13.9 years. Patients with L5/S1 disc degeneration were associated with higher odds of facet joint osteoarthritis (odds ratio = 2.28, 95% confidence interval = 1.23-4.23, P = 0.008). There was a positive correlation between L5/S1 disc degeneration grade and the facet joint grade (r = 0.365, P > 0.001). Grade IV facet joint osteoarthritis did not appear in grades I or II disc degeneration (P > 0.001). The average facet joint width decreased significantly with increasing Pfirrmann grading (P = 0.017). The difference in facet joint angle between groups was not statistically significant (P = 0.532). The differences in the angular and translational motions were not statistically significant (P = 0.530, and 0.510, respectively). CONCLUSION: A positive correlation exists between L5/S1 disc degeneration and facet joint osteoarthritis grades. The facet joint space width decreases significantly with increasing grade of disc degeneration.

The role of mixing in potassium ferrate(VI) consumption kinetics and disinfection of bypass wastewater.

Bypass wastewaters need an appropriate auxiliary treatment to address their broad range of chemical and bacterial characteristics. The dual capacity of potassium ferrate(VI) as disinfectant/oxidant and coagulant may be useful in a sustainable process retrofit to provide adequate treatment to such wastewaters. However, the engineering aspects of potassium ferrate(VI) based technology to retrofit within existing coagulation-flocculation-sedimentation basins have not been studied. This study investigated, for the first time, the role of rapid mixing on the rate of potassium ferrate(VI) decay and disinfection in bypass wastewaters from extreme wet weather flow events. First-order, second-order, and double exponential models were fit to the potassium ferrate(VI) consumption data, and the double exponential model was able to represent the potassium ferrate(VI) decay in all conditions with a high coefficient of determination and low mean square error. In addition, Chick-Watson and Hom models were tested in this study, and both fit the E. coli disinfection results. The rates of potassium ferrate(VI) consumption and disinfection derived from the models were higher using 500-1000 rpm rapid mixing speeds than they were when magnetic stirrer mixing was used for the same initial dosage and wastewater sample. There was no significant increase in the potassium ferrate(VI) consumption or disinfection rates with the increase of the rapid mixing speeds from 500 to 1000 rpm which revealed that the reactions were kinetically controlled. The coagulation capability of potassium ferrate(VI) enhanced the sedimentation ability and contributed almost the same as the chemical disinfection capability to the overall E. coli removal. This study suggests that potassium ferrate(VI) can be implemented in existing facilities that mix coagulants to enhance primary sedimentation, yet potassium ferrate(VI) can provide both disinfection and coagulation at lower mixing speeds.

Predictors of 30- and 90-day readmission following craniotomy for malignant brain tumors: analysis of nationwide data.

Hospital readmissions are a major contributor to increased health care costs and are associated with worse patient outcomes after neurosurgery. We used the newly released Nationwide Readmissions Database (NRD) to describe the association between patient, hospital and payer factors with 30- and 90-day readmission following craniotomy for malignant brain tumor. All adult inpatients undergoing craniotomy for primary and secondary malignant brain tumors in the NRD from 2013 to 2014 were included. We identified all cause readmissions within 30- and 90-days following craniotomy for tumor, excluding scheduled chemotherapeutic procedures. We used univariate and multivariate models to identify patient, hospital and administrative factors associated with readmission. We identified 27,717 admissions for brain tumor craniotomy in 2013-2014, with 3343 (13.2%) 30-day and 5271 (25.7%) 90-day readmissions. In multivariate analysis, patients with Medicaid and Medicare were more likely to be readmitted at 30- and 90-days compared to privately insured patients. Patients with two or more comorbidities were more likely to be readmitted at 30- and 90-days, and patients discharged to skilled nursing facilities or home health care were associated with increased 90-day readmission rates. Finally, hospital procedural volume above the 75th percentile was associated with decreased 90-day readmission rates. Patients treated at high volume hospitals are less likely to be readmitted at 90-days. Insurance type, non-routine discharge and patient comorbidities are predictors of postoperative non-scheduled readmission. Further studies may elucidate potentially modifiable risk factors when attempting to improve outcomes and reduce cost associated with brain tumor surgery.

Proliferative Index in Pediatric Pilocytic Astrocytoma by Region of Origin and Prediction of Clinical Behavior.

BACKGROUND/AIMS: Pilocytic astrocytomas are common pediatric tumors. Molecular profiles vary with location of origin. Comparisons of proliferation have not been reported. We sought to identify differences in growth by region and whether these predict clinical behavior. METHODS: A retrospective review of all patients undergoing surgery for a pilocytic astrocytoma at Children's Hospital LA from 2003 to 2015 was completed. Tumor location, determined by imaging, was stratified into infratentorial, supratentorial, or optic pathway. Proliferation was measured by Ki-67 immunostaining. A p value of 0.05 was deemed significant. RESULTS: 77 patients were identified. 51 had posterior fossa tumors, 12 had supratentorial tumors, and 14 had optic pathway tumors. Mean Ki-67 score was 3.67, 4.09, and 3.83%, respectively (p = 0.82). Ki-67 of ≥4% trended towards recurrence (p = 0.11), incomplete resection (p = 0.15), and younger age at presentation (p = 0.04). Ki-67 was weakly correlated with shorter survival after surgery (r = -0.103, p = 0.41). Partial resection strongest predicted recurrence (p < 0.001; OR = 13.0). CONCLUSION: Proliferative index does not change by location. Higher cell proliferation was seen in younger patients and associated with shorter time to and a higher risk of recurrence. Further study is needed to identify predictors for clinical behavior. Importance of Study: This study provides a detailed analysis of the proliferative indices of tumors arising from characteristic locations within the brain. With recent advances in our understanding of the differences in molecular and genetic profiles despite similar histologic diagnoses, we felt that it was important to review whether there were unique components of tumor behavior that could be identified. In turn, we sought to determine whether tumor behavior could be used to predict the clinical course. This knowledge is important, given that not every tumor may undergo complete surgical resection, and that some lesions may require more aggressive upfront adjuvant therapy or be closely monitored for recurrence.

Pulp and Paper Mill Effluent Management.

This is a review of literature published in 2017 related to the prevention of water pollution by or recovery of beneficial materials from wastewater produced in the pulp and paper industry. This review includes the following main sections: cleaner production, biological treatment, and physico-chemical treatment.

Pulp and Paper Mill Effluent Management.

This is a review of literature published in 2016 related to the prevention of water pollution by or recovery of beneficial materials from wastewater produced in the pulp and paper industry. This review includes the following sections: pulp and paper wastewater management, pollution avoidance, process modelling, physical and chemical treatment, biological treatment, phytoremediation and value added materials.

Simulated outcomes for durotomy repair in minimally invasive spine surgery.

Minimally invasive spine surgery (MISS) is increasingly performed using endoscopic and microscopic visualization, and the captured video can be used for surgical education and development of predictive artificial intelligence (AI) models. Video datasets depicting adverse event management are also valuable, as predictive models not exposed to adverse events may exhibit poor performance when these occur. Given that no dedicated spine surgery video datasets for AI model development are publicly available, we introduce Simulated Outcomes for Durotomy Repair in Minimally Invasive Spine Surgery (SOSpine). A validated MISS cadaveric dural repair simulator was used to educate neurosurgery residents, and surgical microscope video recordings were paired with outcome data. Objects including durotomy, needle, grasper, needle driver, and nerve hook were then annotated. Altogether, SOSpine contains 15,698 frames with 53,238 annotations and associated durotomy repair outcomes. For validation, an AI model was fine-tuned on SOSpine video and detected surgical instruments with a mean average precision of 0.77. In summary, SOSpine depicts spine surgeons managing a common complication, providing opportunities to develop surgical AI models.

Awake Robotic Minimally-Invasive Transforaminal Lumbar Interbody Fusion under Spinal Anesthesia: a Prospective Study with 1-year Follow-up.

BACKGROUND: We describe our protocol and outcomes of awake robotic minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) under spinal anesthesia. METHODS: We conducted a prospective study of 10 consecutive patients undergoing awake robotic single-level MIS-TLIF with the Mazor X robot. We prospectively collected patient-reported outcomes (back and leg pain VAS, and Oswestry Disability Index) pre-operatively, at the 1-month, and 1-year follow-up, and assessed fusion and screw placement accuracy with the 1-year CT scan. RESULTS: Median age was 61 years (IQR=57.7-66); median BMI 27kg/m2. No intraoperative complications reported. 9/10 patients were discharged home, 50% discharged on the day of surgery. Median length of stay was 16.5h (IQR=5-35.5); median follow-up 12.5 months (IQR=12-13.5), with 9 patients having at least 12-month follow-up, with CT scans documenting good screw placement (Gertzbein-Robbins Grade A) and solid bony fusion. Median pre-op back pain VAS was 7.8 (IQR=6.9-8) versus 1.5 (IQR=0-3.2) at 1-month post-op, p<0.01, and 0 (IQR=0-1) at 1-year follow-up, p<0.01; median preop leg pain 8 (IQR=7.4-8) versus 0 (IQR=0-1.2) at 1-month post-op, p<0.01, and 0 (IQR=0-2) at 1-year follow-up, p<0.01; median preop ODI 47.5 (IQR=27.8-57.5) versus 4 (IQR=0-16) at 1-month post-op, p<0.01, and 0 (IQR=0-7) at 1-year follow-up, p<0.01. Median preoperative disc high of the index level 8mm (IQR=2.4-9.5), versus 11.4mm (IQR=9.2-11.2) postoperatively, p< 0.01. Median preoperative lordosis of the index level 5 degrees (IQR=3.4-8.5), versus 10.1 degrees (7.3-12.2) postoperatively, p< 0.01. CONCLUSIONS: Our study showed significant improvement in PROs at 1-month and 1-year follow-up after awake robotic MIS-TLIF, as well as solid bony fusion on CT scans.

POCUS literature primer: key papers on POCUS in cardiac arrest and shock.

OBJECTIVE: The objective of this study is to identify the top five most influential papers published on the use of point-of-care ultrasound (POCUS) in cardiac arrest and the top five most influential papers on the use of POCUS in shock in adult patients. METHODS: An expert panel of 14 members was recruited from the Canadian Association of Emergency Physicians (CAEP) Emergency Ultrasound Committee and the Canadian Ultrasound Fellowship Collaborative. The members of the panel are ultrasound fellowship trained or equivalent, are engaged in POCUS research, and are leaders in POCUS locally and nationally in Canada. A modified Delphi process was used, consisting of three rounds of sequential surveys and discussion to achieve consensus on the top five most influential papers for the use of POCUS in cardiac arrest and shock. RESULTS: The panel identified 39 relevant papers on POCUS in cardiac arrest and 42 relevant papers on POCUS in shock. All panel members participated in all three rounds of the modified Delphi process, and we ultimately identified the top five most influential papers on POCUS in cardiac arrest and also on POCUS in shock. Studies include descriptions and analysis of safe POCUS protocols that add value from a diagnostic and prognostic perspective in both populations during resuscitation. CONCLUSION: We have developed a reading list of the top five influential papers on the use of POCUS in cardiac arrest and shock to better inform residents, fellows, clinicians, and researchers on integrating and studying POCUS in a more evidence-based manner.

RéSUMé: OBJECTIF: L'objectif de cette étude est d'identifier les cinq articles les plus influents publiés sur l'utilisation de l'échographie au point de soin (POCUS) dans l'arrêt cardiaque et les cinq articles les plus influents sur l'utilisation de POCUS dans le choc chez les patients adultes. MéTHODES: Un comité d'experts composé de 14 membres a été recruté par le Comité d'échographie d'urgence de l'Association canadienne des médecins d'urgence (ACMU) et le Canadian Ultrasound Fellowship Collaborative. Les membres du comité sont formés en échographie ou l'équivalent, participent à la recherche sur le POCUS et sont des chefs de file du POCUS à l'échelle locale et nationale au Canada. Un processus Delphi modifié a été utilisé, consistant en trois séries de sondages séquentiels et de discussions pour parvenir à un consensus sur les cinq articles les plus influents pour l'utilisation de POCUS dans les arrêts cardiaques et les chocs. RéSULTATS: Le panel a identifié 39 articles pertinents sur le POCUS en arrêt cardiaque et 42 articles pertinents sur le POCUS en état de choc. Tous les membres du panel ont participé aux trois cycles du processus Delphi modifié, et nous avons finalement identifié les cinq articles les plus influents sur le POCUS en arrêt cardiaque et aussi sur le POCUS en état de choc. Les études comprennent des descriptions et des analyses de protocoles POCUS sûrs qui ajoutent de la valeur d'un point de vue diagnostique et pronostique dans les deux populations pendant la réanimation. CONCLUSION: Nous avons dressé une liste de lecture des cinq principaux articles influents sur l'utilisation du POCUS en cas d'arrêt cardiaque et de choc afin de mieux informer les résidents, les boursiers, les cliniciens et les chercheurs sur l'intégration et l'étude du POCUS d'une manière plus factuelle.

Frailty as a Predictor of Postoperative Morbidity and Mortality in Patients Aged 80 Years and Older Undergoing Instrumented Fusion.

BACKGROUND AND OBJECTIVES: Degenerative spine disease is a leading cause of disability, with increasing prevalence in the older patients. While age has been identified as an independent predictor of outcomes, its predictive value is limited for similar older patients. Here, we aimed to determine the most predictive frailty score of adverse events in patients aged 80 and older undergoing instrumented lumbar fusion. METHODS: We proceeded with a multisite (3 tertiary academic centers) retrospective review including patients undergoing instrumented fusion aged 80 and older from January 2010 to present. A composite end point encompassing 30-day return to operating room, readmission, and mortality was created. We estimated the area under the receiver operating characteristic curve for frailty scores (Modified Frailty Index-5 [MFI-5], Modified Frailty Index-11 [MFI-11], and Charlson Comorbidity Index [CCI]) in relation to that composite score. In addition, we estimated the association between each score and the composite end point by means of logistic regression. RESULTS: A total of 153 patients with an average age of 85 years at the time of surgery were included. We observed a 30-day readmission rate of 11.1%, reoperation of 3.9%, and mortality of 0.6%. The overall rate of the composite end point at 30 days was 25 (15.1%). The AUC for MFI-5 was 0.597 (0.501-0.693), for MFI-11 was 0.620 (0.518-0.723), and for CCI was 0.564 (0.453-0.675). The association between the scores and composite end point did not reach statistical significance for MFI-5 (odds ratio [OR] = 1.45 [0.98-2.15], P = .061) and CCI (OR = 1.13 [0.97-1.31], P = .113) but was statistically significant for MFI-11 (OR = 1.46 [1.07-2.00], P = .018). CONCLUSION: This is the largest study comparing frailty index scores in octogenarians undergoing instrumented lumbar fusion. Our findings suggest that while MFI-11 score correlated with adverse events, the predictive ability of existing scores remains limited, highlighting the need for better approaches to identify select patients at age extremes.

Emergency physician gender and head computed tomography orders for older adults who have fallen.

OBJECTIVE: Physicians vary in their computed tomography (CT) scan usage. It remains unclear how physician gender relates to clinical practice or patient outcomes. The aim of this study was to assess the association between physician gender and decision to order head CT scans for older emergency patients who had fallen. METHODS: This was a secondary analysis of a prospective observational cohort study conducted in 11 hospital emergency departments (EDs) in Canada and the United States. The primary study enrolled patients who were 65 years and older who presented to the ED after a fall. The analysis evaluated treating physician gender adjusted for multiple clinical variables. Primary analysis used a hierarchical logistic regression model to evaluate the association between treating physician gender and the patient receiving a head CT scan. Secondary analysis reported the adjusted odds ratio (OR) for diagnosing intracranial bleeding by physician gender. RESULTS: There were 3663 patients and 256 physicians included in the primary analysis. In the adjusted analysis, women physicians were no more likely to order a head CT than men (OR 1.26, 95% confidence interval 0.98-1.61). In the secondary analysis of 2294 patients who received a head CT, physician gender was not associated with finding a clinically important intracranial bleed. CONCLUSIONS: There was no significant association between physician gender and ordering head CT scans for older emergency patients who had fallen. For patients where CT scans were ordered, there was no significant relationship between physician gender and the diagnosis of clinically important intracranial bleeding.

Pilot-scale anaerobic co-digestion of municipal wastewater sludge with restaurant grease trap waste.

The maximum feasible loading rate of grease trap waste (GTW) to the municipal wastewater sludge (MWS) was investigated using two 1300 L pilot-scale (1200 L active volume) digesters under mesophilic conditions at a 20 day solids retention time. During the co-digestion, the test reactor received a mixture of GTW and MWS while the control reactor received only MWS. The test digester loading was increased incrementally to a maximum of 280% of the control digester COD loading. The highest feasible GTW loading was determined to be 23% and 58% in terms of its total 1.58 kg VS/(m(3) d) and 3.99 kg COD/(m(3) d) loadings, respectively. This test digester COD loading represented 240% of the control digester COD loading. At this loading, test digester biogas production was 67% greater than that of the control. During the test digester quasi steady state loading period when VS from GTW represented 19% of its total VS loading, the test digester COD and VS removal rates were 2.5 and 1.5 fold those of the control digester, respectively. The test digester biogas production declined markedly when the percentage of VS from GTW in its feed was increased to 30% of its total VS loading. Causes of the reduced biogas production were investigated and attributed to inhibition due to long chain fatty acid accumulation.

Vertebral Aneurysmal Bone Cyst Mimicking Osteosarcoma: Case Report and Review of the Literature.

Aneurysmal bone cysts are benign osseous lesions containing blood-filled cavities separated by walls of connective tissue. They can be difficult to identify clinically due to similarities in presentation, imaging, and histology with other pathologies. Specifically, it is important to distinguish these benign lesions from malignant processes, as both surgical and medical management differ. We present the case of a 21-year-old patient who presented with impaired motor and sensory function in his lower extremities. Radiologic findings were concerning for an invasive neoplasm, and the intraoperative frozen section supported this conclusion. However, an additional histological investigation was confirmatory for a diagnosis of an aneurysmal bone cyst. The patient underwent corpectomy, laminectomy, and a posterior spinal fusion, and regained motor and sensory function shortly thereafter. This report details the importance of considering aneurysmal bone cysts in the differential of infiltrative bone lesions, despite their benign nature, as medical and surgical management can vary greatly.

Two- versus multi-rod constructs for adult spinal deformity: A systematic review and Random-effects and Bayesian meta-analysis.

BACKGROUND: Surgical approaches in adult spinal deformity are associated with high rates of adverse events including hardware failure and rod fracture. Recently, some reports have emerged comparing multiple-rod constructs with 2-rod constructs suggesting potential benefits with the former. However, these have been limited by variability in observed outcomes, which have limited the change of paradigm in adult spinal deformity surgery. OBJECTIVE: To compare the rate of rod fracture, pseudoarthrosis, proximal junctional kyphosis and re-operation between 2-RC and M-RC. METHODS: MEDLINE/Pubmed, Web of Science and Embase were searched without language restrictions for relevant articles from inception until October 2021. All observational cohort studies assessing patients with ADS undergoing 3-column osteotomy and comparing 2-RC with M-RC procedures on pseudarthrosis, rod fracture, kyphosis or reoperation were included. Data were independently extracted by 2 authors. Random-effects and Bayesian meta-analysis were used. RESULTS: Six primary studies met inclusion criteria, yielding a total of 448 participants, with 223 receiving 2-RC and 225 M-RC. The random-effects meta-analysis pointed to a significantly lower risk of rod fracture associated with M-RC (RR = 0.43, 95 %CI = 0.28-0.66), with moderate heterogeneity being observed (I2 = 20 %, p = 0.28). The random-effects meta-analysis pointed to a lower risk of pseudoarthrosis with M-RC than with 2-RC (RR = 0.49, CI = 0.28-0.84, to a lower rate of re-operation with M-RC than with 2-RC (RR = 0.52, CI = 0.28-0.97) and to a similar rate of proximal junctional kyphosis between 2-RC and M-RC patients (RR = 0.91, CI = 0.60-1.39). Low heterogeneity was observed for studies comparing pseudoarthrosis (I2 = 9 %, p = 0.35), re-operation (I2 = 0 %, p = 0.41) and proximal junctional kyphosis (I2 = 0 %, p = 0.85). DISCUSSION: These findings suggest that multiple rod-fracture constructs are associated with lower rates of rod fracture, re-operation rates, pseudoarthrosis but not proximal junctional kyphosis. Future studies should address the impact of other modulators of heterogeneity such as body mass index, metal alloys and length of the constructs.