bluuebunny/crossref_metadata_2025 huggingface dataset:
P.169 Reduced radiation CT imaging for augmented reality spinal surgery
applications
Authors: de Lotbiniere-Bassett M , Schonfeld E , Jansen T , Anthony D , Veeravagu A
Published: January 2022

Background: There is growing evidence for the use
of augmented reality (AR) in pedicle screw placement in spinal surgery to
increase surgical accuracy, improve clinical outcomes and reduce the
radiation exposure required for intraoperative navigation. Auto-segmentation
is the cornerstone of AR applications because it correlates patient-specific
anatomy to structures segmented from preoperative computed tomography (pCT)
images. These AR techniques allow for a reduction in the radiation dose
required to acquire CT images while maintaining accurate segmentation.
Methods: In this study, we methodically increase
the noise that is introduced into CT images to determine the image quality
threshold that is required for auto-segmentation on pCT. We then enhance the
images with denoising algorithms to evaluate the effect on the segmentation.
Results: The pCT radiation dose is decreased to
below the current lowest clinical threshold and the resulting images still
produce segmentations that are appropriate for input into AR applications.
The application of denoising algorithms to the images resulted in increased
artifacts and decreased bone density. Conclusions:
The CT image quality that is required for successful AR auto-segmentation is
lower than that which is currently employed in spine surgery. Future
research is required to identify the specific, clinically relevant radiation
dose thresholds.
P.173 Evaluation of Arterial Spin Labeling (ASL) Perfusion Imaging in
Poorly-Defined Focal Epilepsy in Children
Authors: Lam J , Tomaszewski P , Gilbert G , Moreau JT , Guiot M , Albrecht S , Farmer J , Atkinson J , Saint-Martin C , Wintermark P , Bernhardt B , Baillet S , Dudley RW
Published: January 2022

Background: Poorly-defined cases (PDCs) of focal
epilepsy are cases with no/subtle MRI abnormalities or have abnormalities
extending beyond the lesion visible on MRI. Here, we evaluated the utility
of Arterial Spin Labeling (ASL) MRI perfusion in PDCs of pediatric focal
epilepsy. Methods: ASL MRI was obtained in 25
consecutive children presenting with poorly-defined focal epilepsy (20 MRI-
positive, 5 MRI-negative). Qualitative visual inspection and quantitative
analysis with asymmetry and Z-score maps were used to detect perfusion
abnormalities. ASL results were compared to the hypothesized epileptogenic
zone (EZ) derived from other clinical/imaging data and the resection zone in
patients with Engel I/II outcome and >18 month follow-up.
Results: Qualitative analysis revealed perfusion
abnormalities in 17/25 total cases (68%), 17/20 MRI-positive cases (85%) and
none of the MRI-negative cases. Quantitative analysis confirmed all cases
with abnormalities on qualitative analysis, but found 1 additional
true-positive and 4 false-positives. Concordance with the surgically-proven
EZ was found in 10/11 cases qualitatively (sensitivity=91%,
specificity=50%), and 11/11 cases quantitatively (sensitivity=100%,
specificity=23%). Conclusions: ASL perfusion may
support the hypothesized EZ, but has limited localization benefit in
MRI-negative cases. Nevertheless, owing to its non-invasiveness and ease of
acquisition, ASL could be a useful addition to the pre-surgical MRI
evaluation of pediatric focal epilepsy.
P.174 Accuracy of pedicle screw placement with X-ray versus O-arm
image-guided navigation
Authors: Neuburger L , Cheng Y , Fourney DR
Published: January 2022

Background: Image-guided navigation is routinely
used in spine surgery to improve placement of pedicle screws. However, most
reports have relied on two-dimensional X-ray evaluation to determine
accuracy of screw positioning. In this study, computed tomography (CT) and
O-arm imaging enabled a detailed three-dimensional comparison of screw
placement. The objective was to compare the accuracy of pedicle screw
placement with intraoperative X-ray versus O-arm image-guided navigation.
Methods: This was a retrospective analysis of
image-guided pedicle screw placement in patients who underwent spinal
instrumentation. Post-operative CT and O-arm imaging allowed grading of
screw accuracy based on pedicle breaches. Clinical outcomes included patient
and operative factors. Results: Pedicle screws were
placed in 208 patients (1116 screws). Three-dimensional O-arm guidance was
utilized for 126 patients, while the remainder underwent two-dimensional
X-ray imaging and post-operative CT assessment. O-arm navigation was
associated with improved pedicle screw accuracy: pedicle breaches were more
likely to be low grade (odds ratio 2.84, p=0.001) and less likely to be
medium grade (odds ratio 0.35, p=0.007) or high grade (odds ratio 0.31,
p=0.025). Conclusions: This study provided a detailed
comparison of surgical accuracy with X-ray versus O-arm guidance. Navigation
with O-arm imaging is associated with benefits in spinal instrumentation,
without impacting operative risks for patients.
P.179 An International Comparison of Neurosurgical Competence by Design
Curriculum
Authors: Rabski J , Moodie G
Published: January 2022

Background: Prior to its recent introduction into
Canadian neurosurgical curriculum, Competence by Design (CBD) principles
have been implemented across many international neurosurgical training
programs for several years. As such, comparing other international
competency-based educational frameworks and curricula can help anticipate,
avoid or mitigate potential future challenges for Canadian neurosurgical
trainees. Methods: A comparative web-based analysis
of neurosurgical postgraduate medical education documents and resources
provided by medical accreditation and regulatory bodies of Canada, the
United States, the United Kingdom and Australasia, was performed.
Results: All four countries varied considerably
across four major curriculum-based themes: 1) general program structure; 2)
overarching foundational competency frameworks; 3) types and numbers of
performance assessments required and; 4) curricular learning outcomes. In
particular, the expected progression and degree of competence required of
neurosurgical residents when performing entrustable professional activities
(EPAs) or defined tasks of neurosurgical practice, varied across all
countries. Differences in types of neurosurgical EPAs and number of required
assessments demonstrating a trainee’s competence achievement were also
appreciated. Conclusions: This study revealed
variations across competency-based neurosurgical curricula proposed by four
international medical training regulatory bodies. Differences in types of
EPAs and their required degree of competence achievement suggests potential
disconnects between neurosurgical educational outcomes and actual medical
practice.
P.181 High-Fidelity Simulation-Based Microsurgical Training for
Neurosurgical Residents
Authors: Santyr B , Abbass M , Chalil A , Krivosheya D , Denning LM , Mattingly TK , Haji F , Lownie SP
Published: January 2022

Background: Microsurgical techniques remain a
cornerstone of neurosurgical training. Despite this, neurosurgical
microvascular case volumes are decreasing as endovascular and minimally
invasive options expand. As such, educators are looking towards simulation
to supplement operative exposure. We review a single institution’s
experience with a comprehensive, longitudinal microsurgical simulation
training program, and evaluate its effectiveness.
Methods: Consecutive postgraduate year 2 (PGY-2)
neurosurgery residents completed a one-year curriculum spanning 17 training
sessions divided into 5 modules of increasing fidelity. Both perfused duck
wing and live rat femoral vessel training modules were used. Trainee
performance was video recorded and blindly graded using the Objective
Structured Assessment of Technical Skills Global Rating Scale.
Results: Eighteen participants completed 107
microvascular anastomoses during the study. There was significant
improvement in six measurable skills during the curriculum. Mean overall
score was significantly higher on the fifth attempt compared to the first
attempt for all 3 live anastomotic modules (p<0.001). Each module had a
different improvement profile across the skills assessed. The greatest
improvement was observed during artery-to-artery anastomosis.
Conclusions: This high-fidelity microsurgical
simulation curriculum demonstrated a significant improvement in the six
microneurosurgical skills assessed, supporting its use as an effective
teaching model. Transferability to the operative environment is actively
being investigated.
P.190 Choosing Endovascular Treatment or Thrombolysis in Patients with
Pre-stroke Comorbidities: UNMASK EVT, a Worldwide Survey
Authors: Ganesh A , Kashani N , Ospel JM , Wilson AT , Foss MM , Saposnik G , Al-Mekhlafi MA , Goyal M , Menon BK , Hill MD
Published: January 2022

Background: Decisions to treat large-vessel
occlusion with endovascular therapy(EVT) or intravenous alteplase depend on
how physicians weigh benefits against risks when considering patients’
pre-stroke comorbidities. Methods: In an
international survey, experts chose treatment approaches under current
resources and under assumed ideal conditions for 10 of 22 randomly assigned
case-scenarios. Five included comorbidities(metastatic/non-metastatic
cancer, cardiac/respiratory/renal disease, non-disabling/mild cognitive
impairment[MCI], physical dependence). We examined scenario/respondent
characteristics associated with EVT/alteplase decisions using multivariable
logistic regressions. Results: Among 607
physicians(38 countries), EVT was favoured in 1,097/1,379(79.6%) responses
for comorbidity-related scenarios under current resources versus
1,510/1,657(91.1%,OR:0.38, 95%CI.0.31-0.47) for six “level-1A” scenarios
(assuming ideal conditions:82.7% vs 95.1%,OR:0.25,0.19-0.33). However, this
was reversed on including all other scenarios(e.g. under current
resources:3,489/4,691[74.4%], OR:1.34,1.17-1.54). Responses favouring
alteplase for comorbidity-related(e.g.75.0% under current resources)
scenarios were comparable to level-1A scenarios(72.2%) and higher than all
others(60.4%). No comorbidity-related factor independently diminished
EVT-odds. MCI and dependence carried higher alteplase-odds; cancer and
cardiac/respiratory/renal disease had lower odds. Relevant respondent
characteristics included performing more EVT cases/year (higher EVT, lower
alteplase-odds), practicing in East-Asia (higher EVT-odds), and in
interventional neuroradiology(lower alteplase-odds vs neurology).
Conclusions: Moderate-to-severe comorbidities did
not consistently deter experts from EVT, suggesting equipoise about
withholding EVT based on comorbidities. However, alteplase was often
foregone when respondents chose EVT.
P.194 In search of real-world neuroprotection in mechanical thrombectomy
for ischemic stroke
Authors: Mattingly TK , Whyte R , Kohli GS , Susa S , Bender MT , Bhalla T
Published: January 2022

Background: The promise of neuroprotection for
stroke remains elusive. Common medications in endovascular stroke
thrombectomy have putative neuroprotective mechanisms in basic science
literature. We evaluated our stroke registry for evidence that these
medications have any impact on clinically meaningful outcome.
Methods: A retrospective stroke thrombectomy
database was evaluated for clinical and angiographic outcomes of patients
receiving IV or IA tPA, Heparin, or Verapamil during procedure. Univariate
analysis evaluated associations with periprocedure hemorrhage,
recanalization, and functional outcomes. Results: 284
patients underwent mechanical thrombectomy over 2.75 years. For
periprocedural hemorrhage, IV tPA (OR 0.457, CI 0.261-0.811, p=0.008) and
Heparin (1.897, CI 1.112-3.205, p=0.019) had significant relationships. No
medication had impact on favorable recanalization (TICI 2b/3). Heparin had a
negative impact on 90day mRS 0-2 (OR 0.563, CI 0.348-0.901, p=0.023).
Favorable recanalization remains associated with favorable outcomes at
90days (OR 2.066, CI 1.063-4.069, p=0.0361).
Conclusions: While the adjunctive use of 3
commonly used periprocedural medications have a logical role in the
mechanical thrombectomy eg IA tPA for clot lysis, they do not have clinical
benefit that represents neuroprotection. Multivariate analysis may show more
effect. A role for intraarterial neuroprotective agents exists given only
45% of patients in this series achieved functional independence.
P.226 Variations in and Determinants of Length of Stay at an Academic
Spinal Care Center from 2006-2019
Authors: Dandurand C , Hindi MN , Ailon T , Boyd M , Charest-Morin R , Dea N , Dvorak M , Fisher C , Kwon B , Paquette S , Street J
Published: January 2022

Background: Length of stay (LOS) is a surrogate
for care complexity and a determinant of occupancy and service provision.
Our primary goal was to assess changes in and determinants of LOS at a
quaternary spinal care center. Secondary goals included identifying
opportunities for improvement and determinants of future service planning.
Methods: This is a prospective study of patients
admitted from 2006 to 2019. Data included demographics, diagnostic category
(degenerative, oncology, deformity, trauma, other), LOS (mean, median,
interquartile range, standard deviation) and in-hospital adverse events
(AEs). Results: 13,493 admissions were included. Mean
age has increased from 48.4 (2006) to 58.1 years (2019) (p=<0.001). Mean
age increased overtime for patients treated for deformity (p=<0.001),
degenerative pathology (p=<0.001) and trauma (p=<0.001), but not
oncology (p=0.702). Overall LOS has not changed over time (p=0.451). LOS
increased in patients with degenerative pathology (p=0.019) but not
deformity (p=0.411), oncology (p=0.051) or trauma (p=0.582). Emergency
admissions increased overtime for degenerative pathologies (p=<0.001).
AEs and SSIs have decreased temporally (p=<0.001).
Conclusions: This is the first North American
study to analyze temporal trends in LOS for spine surgery in an academic
center. Understanding temporal trends in LOS and patient epidemiology can
provide opportunities for intervention, targeted at the geriatric
populations, to reduce LOS.
P.201 Disruption of the Frontal Aslant Tract is Associated with Transient
Aphasia and not Agraphia: A Neurosurgical Case Report
Authors: Abbass M , Lau JC , Megyesi J
Published: January 2022

Background: The frontal aslant tract (FAT) is a
recently discovered white-matter tract connecting the medial superior
frontal gyrus to the inferior frontal gyrus. There is increasing evidence
for its importance in speech initiation and production. Despite this, there
remains limited evidence demonstrating clinical outcomes when lesioning this
tract. Methods: Medical records for the case were
reviewed. Imaging was exported and tractography was performed using 3D
Slicer. Results: A 58-year-old female presented with
a focal seizure and imaging demonstrating a left frontal extra-axial lesion.
She underwent a left frontal craniotomy for tumour debulking and biopsy. The
final pathology was consistent with a diffuse large B-cell lymphoma.
Postoperatively, she presented with expressive aphasia without agraphia. She
was able to write out answers to questions she could not verbalize. We used
tractography to provide evidence of postoperative disruption to her left
FAT. At a 6-week clinical follow-up, her language deficits were clinically
resolved. Conclusions: To our knowledge, this is the
first reported case of aphasia without agraphia seen with disruption of the
left FAT. Further elucidating clinical outcomes of disrupting the dominant
FAT will aid in improved patient counselling, prognostication and
neurosurgical planning. Further research is required to investigate the
mechanisms underlying language recovery and handwriting.
P.204 Integration of patient directed approach in pituitary tumor
management – The Ottawa Hospital experience
Authors: Druce I , Doyle M , Arnaout A , Agbi C , Keely E , Malcolm J , Alkherayf F
Published: January 2022

Background: Pituitary adenomas are common and
often require complex multidisciplinary care with multiple specialists. This
may result in a health care system that is challenging for patients to
navigate. Audits of care at our institution revealed opportunities for
improvement to better align care with patients’ needs.
Methods: A quality improvement initiative that
incorporated a patient advisory committee of patients who had received
treatment for pituitary adenoma at our center and their family members was
used to help identify opportunities for improvement. The patient-identified
gaps in care included the need to coordinate and minimize appointments and
the desire for better communication and education. Based on this
information, changes were implemented to the pituitary program, including
increasing access to the multidisciplinary clinic and developing a
standardized and centralized triage process. Results:
A pre and post-intervention analysis consisting of retrospective chart
reviews revealed that these changes had an impact on wait times for first
assessment, and a significant shift in location of this first visit – with a
larger proportion of patients being seen in the multidisciplinary clinic
after intervention. Conclusions: We demonstrate that
patient involvement, beyond individual patient-physician interactions, can
lead to meaningful and observable changes, and can improve the quality of
care for pituitary adenoma.
P.209 Novel 3D printing for complex cranial reconstruction in
neurosurgery - A case series
Authors: Lannon M , Algird A , Alsunbul W , Wang B
Published: January 2022

Background: Cranial reconstruction is a common
consequence of neurosurgical disease and intervention following craniectomy,
trauma, infection, congenital defects, or neoplasm. Most commonly, Computer
Aided Design-Computer Aided Manufacturing (CAD-CAM) technology is utilized
in cases where autologous bone cannot be used. These patient-specific
implants provide excellent cosmesis, however individual costs range from
$800-15,000, making routine use challenging in the current Canadian health
care environment. Here we present a novel method using desktop 3D printers
to manufacture patient-specific molds for intraoperative reconstruction of
various cranial defects. Methods: Our first patient
presented following two separate traumas requiring decompressive craniectomy
and subsequent posterior fossa decompression without interval cranioplasty.
The second patient required reconstruction during resection of intraosseous
meningioma. Both cases were performed using a
titanium-mesh/poly-methyl-methacrylate (Ti-PMMA) construct draped over the
mold. The third case, cranioplasty following decompressive craniectomy
outside the country, was performed using a “two piece” mold and PMMA was
casted into the mold and allowed to harden. Results:
Patients reported satisfaction with cosmesis, without adverse outcomes. Cost
per case was $50-100, representing an estimated cost savings of $685,000 per
year in Canada. Conclusions: Given excellent outcomes
in addition to cost effectiveness, this case series provides evidence for
use of this alternate technique with similar patient outcomes.
P.213 Long-Term Improvement Of Gait And Cognition After Primary
Endoscopic Third Ventriculostomy (ETV) In Adult Obstructive
Hydrocephalus
Authors: Salterio N , Zwimpfer TJ , Holubkov R , Katzen H , Luciano MG , Jensen H , Nagel SJ , Williams MA , Hamilton MG
Published: January 2022

Background: Adults with obstructive hydrocephalus
often present with cognitive and/or gait dysfunction in addition to symptoms
of raised ICP. We previously reported improvement of cognitive and gait
function 3 months following primary adult ETV. This abstract presents
long-term results in this group. Methods: Obstructive
hydrocephalus was identified based on tri-ventriculomegaly on CT and/or MRI.
Gait velocity (10 m timed gait) and cognitive function (Montreal Cognitive
Assessment [MoCA]) were measured at two timepoints: pre-ETV and ≥9 months
post-ETV. Results: Sixteen adults underwent primary
ETV and completed a long-term assessment. Mean age was 60 years and 10 (63%)
were male. Etiology: 10 (62.5%) congenital and 6 (37.5%) acquired. Mean
long-term follow-up time for cognitive and gait assessments was 14.4 and
13.7 months, respectively. The long-term MoCA within patient median change
was +2 points (n= 15; p = 0.007). Group medians
were 23/30 (pre-ETV) and 26/30 (post-ETV). The long-term gait velocity
within patient median change was +0.4 m/s (n= 12;
p < 0.001). Group medians were 0.7 m/s
(pre-ETV) and 1.3 m/s (post-ETV). Conclusions: ETV in
adults with obstructive hydrocephalus results in long-term improvement of
cognition and gait velocity when assessed ≥9 months post-ETV. Larger cohorts
will determine the generalizability of these results. Hydrocephalus
Association supported project.
P.234 “Inappropriate” spinal ultrasounds for suspected occult spinal
dysraphism in northern Alberta
Authors: Keough M , Thompson A , Mehta V
Published: January 2022

Background: Occult spinal dysraphism (OSD) may be
associated with visible cutaneous manifestations. A common non-pathological
mimic of a dermal sinus tract is an incidental sacrococcygeal dimple.
Choosing Wisely Canada Guidelines recommend these dimples not be imaged.
Methods: This study assessed the appropriateness
of spinal ultrasounds performed for the investigation of an OSD. We
interrogated our local imaging system to analyze spinal ultrasounds being
performed in babies less than 6 months of age, from 2017-2018.
Results: 429 children had spinal ultrasounds
ordered by pediatricians (55%), family doctors (21%), and neonatologists
(20%). 183 children (43%) had imaging indications that was deemed
“inappropriate”. Some of this cohort had further MRI imaging (5/183) or
neurosurgical referral (8/183). None of these children underwent
neurosurgery. 231 (54%) children had appropriate indications for imaging.
Within this cohort MRI imaging (23/231), neurosurgical referral (24/231) and
neurosurgical intervention occurred (4/231). All four “surgical children”
harboured either a dorsal appendage or a subcutaneous lipoma. We estimated,
declining inappropriate scans would save $22, 500 annually.
Conclusions: A significant portion of local
spinal ultrasound requests for OSD are inappropriate. Collaboration with
other sites is ongoing to investigate if the Choosing Wisely guidelines for
imaging this patient population are being practiced more
efficiently.
Direct numerical simulation of turbulent mass transfer at the surface of an open channel flow
Authors: Pinelli Michele , Herlina H. , Wissink J.G. , Uhlmann M.
Published: January 2022

We present direct numerical simulation results of turbulent open channel flow at bulk Reynolds numbers up to 12 000, coupled with (passive) scalar transport at Schmidt numbers up to 200. Care is taken to capture the very large-scale motions which appear already for relatively modest Reynolds numbers. The transfer velocity at the flat, free surface is found to scale with the Schmidt number to the power ‘$-1/2$’, in accordance with previous studies and theoretical predictions for uncontaminated surfaces. The scaling of the transfer velocity with Reynolds number is found to vary, depending on the Reynolds number definition used. To compare the present results with those obtained in other systems, we define a turbulent Reynolds number at the edge of the surface-influenced layer. This allows us to probe the two-regime model of Theofanouset al.(Intl J. Heat Mass Transfer, vol. 19, 1976, pp. 613–624), which is found to correctly predict that small-scale vortices significantly affect the mass transfer for turbulent Reynolds numbers larger than 500. It is further established that the root mean square of the surface divergence is, on average, proportional to the mean transfer velocity. However, the spatial correlation between instantaneous surface divergence and transfer velocity tends to decrease with increasing Schmidt number and increase with increasing Reynolds number. The latter is shown to be caused by an enhancement of the correlation in high-speed regions, which in turn is linked to the spatial distribution of surface-parallel vortices.
Trapping patterns during capillary displacements in disordered media
Authors: Liu Fanli , Wang Moran
Published: January 2022

We investigate the impact of wettability distribution, pore size distribution and pore geometry on the statistical behaviour of trapping in pore-throat networks during capillary displacement. Through theoretical analyses and numerical simulations, we propose and prove that the trapping patterns, defined as the percentage and distribution of trapped elements, are determined by four dimensionless control parameters. The range of all possible trapping patterns and how the patterns are dependent on the four parameters are obtained. The results help us to understand the impact of wettability and structure on trapping behaviour in disordered media.
Three-dimensional geometry and topology effects in viscous streaming
Authors: Chan Fan Kiat , Bhosale Yashraj , Parthasarathy Tejaswin , Gazzola Mattia
Published: January 2022

Recent studies on viscous streaming flows in two dimensions have elucidated the impact of body curvature variations on resulting flow topology and dynamics, with opportunities for microfluidic applications. Following that, we present here a three-dimensional characterization of streaming flows as functions of changes in body geometry and topology, starting from the well-known case of a sphere to progressively arrive at toroidal shapes. We leverage direct numerical simulations and dynamical systems theory to systematically analyse the reorganization of streaming flows into a dynamically rich set of regimes, the origins of which are explained using bifurcation theory.
The unsteady force response of an accelerating flat plate with controlled spanwise bending
Authors: Joshi Kamlesh , Bhattacharya Samik
Published: January 2022

The unsteady force response of an accelerating flat plate, subjected to controlled spanwise bending, is investigated experimentally. The flat plate was held normal to the flow (at an angle of attack of

$90^{\circ }$

), and it was dynamically bent along the spanwise direction with the help of internal actuation. Two bending directions were tested. In one case, part of the plate (denoted by flexion ratio) was bent into the incoming flow (the bend-down configuration). In another case, the plate was bent away from the flow (the bend-up configuration). We used two different aspect ratio (

$AR$

) plates, namely

$AR = 2$

and 3. Three acceleration numbers, namely

$A_c = 0.57$

, 1.6 and 3.2 (corresponding to dimensional acceleration of 0.036, 0.1 and 0.2 m s

$^{-2}$

, respectively) were tested with a fixed terminal Reynolds number (Re) of 18 000. For each acceleration number, three bending durations, namely 1.2, 2.4 and 3.6 s were implemented. The results indicate that the highest impulse was imparted by the highest bending rate (duration 1.2 s) during all three accelerations tested. We show that controlled spanwise bending can significantly change the unsteady force response by manipulating the inertial forces during a start-up manoeuvre. The unsteady forces depend on the vector sum of the forward acceleration and the bending acceleration of the plate. The unsteady drag was augmented when the plate was bent towards the incoming flow. The initial force peaks were significantly reduced when the bending direction was reversed. The development of the edge vortices from the flat plate was measured with the help of particle image velocimetry (PIV) at the 70 % and the 90 % span locations. The PIV measurements were also carried out at the midchord plane closer to the tip region to capture the growth of the tip vortex. The vorticity field calculated from these PIV measurements revealed that controlled bending contributed to a variation in the circulation growth of the edge vortices. During the bend-down case, the circulation growth was faster and the tip vortices stayed closer to the plate. This resulted in increased interaction with the edge vortex at the 90 % span. This interaction was more severe for

$AR = 2$

. During the bend-up case, the growth of the edge vortex was delayed, but the vortex grew for a longer time compared with the bend-down case. Finally, a mathematical model is presented which correctly captured the trend of the force histories measured experimentally during both the bend-up and bend-down cases.
Numerical investigation of turbulence of surface gravity waves
Authors: Zhang Zhou , Pan Yulin
Published: January 2022

In this paper, we numerically study the wave turbulence of surface gravity waves in the framework of Euler equations of the free surface. The purpose is to understand the variation of the scaling of the spectra with wavenumber$k$and energy flux$P$at different nonlinearity levels under different forcing/free-decay conditions. For all conditions (free decay and narrow-band and broad-band forcing) that we consider, we find that the spectral forms approach the wave turbulence theory (WTT) solution$S_\eta \sim k^{-5/2}$and$S_\eta \sim P^{1/3}$at high nonlinearity levels. With a decrease of nonlinearity level, the spectra for all cases become steeper, with the narrow-band forcing case exhibiting the most rapid deviation from WTT. We investigate bound waves and the finite-size effect as possible mechanisms causing the spectral variations. Through a tri-coherence analysis, we find that the finite-size effect is present in all cases, which is responsible for the overall steepening of the spectra and the reduced capacity of energy flux at lower nonlinearity levels. The fraction of bound waves in the domain generally decreases with the decrease of nonlinearity level, except for the narrow-band case, which exhibits a transition at a critical nonlinearity level below which a rapid increase is observed. This increase serves as the main reason for the fastest deviation from WTT with the decrease of nonlinearity in the narrow-band forcing case.
Non-use of modern contraceptives among women in humanitarian contexts: evidence from a qualitative study in Akwa Ibom State, Nigeria
Authors: Ononokpono Dorothy Ngozi , Usoro Nsidibe Akpan , Akpabio Emmanuel Matthew
Published: January 2022

The continuing conflict situation in Nigeria have created over 2 million displaced persons. In 2019, women and children accounted for about 80% of the internally displaced population in the country. Displacement increases the need for reproductive health services. This study explored the reasons for non-use of modern contraceptives among forcibly displaced Bakassi women in Akwa Ibom State, southern Nigeria. Focus group discussions were used to collect data from a convenience sample of 40 women of reproductive age (15–49 years) in two makeshift resettlement camps in the region in January and February 2020. Data were analysed using a qualitative inductive approach, with thematic organization and analysis of the transcribed responses from the focus group discussions. The findings revealed that many of the women were not using modern contraceptives at the time of the study, and the major reasons they gave for non-use were misconceptions, costs, religious beliefs, desire for more children and the inaccessibility and unavailability of contraceptive services. The use of family planning services can be a life-saving intervention in unstable, crisis environments. Programme implementation to address non-use of contraceptive services among women in crisis contexts should target social norm change, reproductive health education, empowerment programmes and health service provision.
Caesarean deliveries, subsequent reproductive behaviour and children ever born in India
Authors: Mishra Rakesh , Goli Srinivas , Chakravorty Swastika , Rammohan Anu
Published: January 2022

Against the backdrop of the alarming rise in Caesarean section (C-section) births in India, this study aimed to examine the association between C-section births, fertility decline and female sterilization in the country. A cross-sectional design was used to investigate the association between C-section delivery and subsequent reproductive behaviour in women in India. Data were from the National Family Health Survey (NFHS-4). The study sample comprised 255,726 currently married women in the age group of 15–49 years. The results showed a strong positive relationship between C-section births and female sterilization. The predicted probabilities (PP) from the multivariate regression model indicated a higher chance of female sterilization in women with C-section births (PP = 0.39,p<0.01) compared with those with non-C-section births (PP = 0.20,p<0.01). Both state-level correlation plots and Poisson regression estimates showed a strong negative relationship between C-section births and mean children ever born (CEB). Based on the results, it may be concluded that the use of C-sections and sterilization were strongly correlated in India at the time of the NFHS-4, thus together contributing to fertility decline. A strong negative association was found between the occurrence of C-sections and CEB. The increased and undesired use of C-section births and consequent female sterilization is a regressive socio-demographic process that often violates women’s rights. Fertility decline should happen through informed choice of family planning and must protect the reproductive rights of women.
Commercial fishing, Inuit rights, and internal colonialism in Nunavut
Authors: Bernauer Warren
Published: January 2022

This paper considers the degree to which the concept of ‘internal colonialism’ accurately describes the political economy of Nunavut’s commercial fisheries. Offshore fisheries adjacent to Nunavut were initially dominated by institutions based in southern Canada, and most economic benefits were captured by southern jurisdictions. Decades of political struggle have resulted in Nunavut establishing a role for itself in both the management of offshore resources and the operation of the offshore fishing industry. However, key decisions about fishery management are made by the federal government, and many benefits from Nunavut’s offshore fisheries continue to accrue to southern jurisdictions. The concept of internal colonialism is therefore a useful concept for understanding the historical development and contemporary conflicts over offshore fisheries. By contrast, Nunavut’s inshore fisheries were established as community development initiatives intended to promote economic well-being and stability. While inshore fisheries primarily benefit Inuit community economies, the growth of inshore fisheries has been hampered by small profit margins, inadequate marine infrastructure, and a dearth of baseline data. The federal government’s failure to support the expansion of inshore fisheries is a manifestation of internal colonialism, insofar as it reflects an unequal distribution of public infrastructure and research.
What Curbs Social Investment? The Effect of Foreign Electoral Outcomes on Childcare Expenditure Levels
Authors: TONELLI SIMONE
Published: January 2022

This study aims to deepen our understanding of social investment expansion proposing a political learning mechanism to link existing institutional and political explanations. When resources are limited, increased spending in social investment often comes at the expense of politically costly retrenchment of established social insurance policies. Previous studies suggest that this trade-off results in existing entitlements crowding out new policies, and that party ideology plays less of a role in determining social policy expansion. I argue that this is because parties face an electoral dilemma, as individual preferences for social investment and social insurance have been shown to differ between groups that partly overlap in their voting behaviour. Applying a policy diffusion framework to the analysis of childcare expenditure, this study proposes that policymakers learn from the political consequences of past decisions made by their foreign counterparts and update their policy choice accordingly. The econometric analysis of OECD data on childcare expenditure shows that governments tend to make spending decisions that follow those of ideologically similar cabinets abroad and that left-wing governments with a divided electorate tend to reduce childcare expenditure if a previous expansionary decision of a foreign incumbent is followed by an electoral defeat. The findings have implications for the study of the politics of social policy development.
Prescription medication use after congenital heart surgery
Authors: Raissadati Alireza , Haukka Jari , Pätilä Tommi , Nieminen Heta , Jokinen Eero
Published: January 2022

Background:

Improvements in mortality after congenital heart surgery have necessitated a shift in focus to postoperative morbidity as an outcome measure. We examined late morbidity after congenital heart surgery based on prescription medication use.

Methods:

Between 1953 and 2009, 10,635 patients underwent congenital heart surgery at <15 years of age in Finland. We obtained 4 age-, sex-, birth-time, and hospital district-matched controls per patient. The Social Insurance Institution of Finland provided data on all prescription medications obtained between 1999 and 2012 by patients and controls. Patients were assigned one diagnosis based on a hierarchical list of cardiac defects and dichotomised into simple and severe groups. Medications were divided into short- and long-term based on indication. Follow-up started at the first operation and ended at death, emigration, or 31 December, 2012.

Results:

Totally, 8623 patients met inclusion criteria. Follow-up was 99.9%. In total, 8126 (94%) patients required prescription medications. Systemic anti-bacterials were the most common short-term prescriptions among patients (93%) and controls (88%). Patients required betablockers (simple hazard ratio 1.9, 95% confidence interval 1.7–2.1; severe hazard ratio 6.5, 95% confidence interval 5.3–8.1) and diuretics (simple hazard ratio 3.2, 95% CI 2.8–3.7; severe hazard ratio 38.8, 95% CI 27.5–54.7) more often than the general population. Both simple and severe defects required medication for cardiovascular, gastrointestinal, psychiatric, neurologic, metabolic, autoimmune, and infectious diseases more often than the general population.

Conclusions:

The significant risk for postoperative cardiovascular and non-cardiovascular disease warrants close long-term follow-up after congenital heart surgery for all defects.
Impact of obesity on post-operative arrhythmias after congenital heart surgery in children and young adults
Authors: Radbill Andrew E. , Smith Andrew H. , Van Driest Sara L. , Fish Frank A. , Bichell David P. , Mettler Bret A. , Christian Karla G. , Edwards Todd L. , Kannankeril Prince J.
Published: January 2022

Background:

Obesity increases the risk of post-operative arrhythmias in adults undergoing cardiac surgery, but little is known regarding the impact of obesity on post-operative arrhythmias after CHD surgery.

Methods:

Patients undergoing CHD surgery from 2007 to 2019 were prospectively enrolled in the parent study. Telemetry was assessed daily, with documentation of all arrhythmias. Patients aged 2–20 years were categorised by body mass index percentile for age and sex (underweight <5, normal 5–85, overweight 85–95, and obese >95). Patients aged >20 years were categorised using absolute body mass index. We investigated the impact of body mass index category on arrhythmias using univariate and multivariate analysis.

Results:

There were 1250 operative cases: 12% underweight, 65% normal weight, 12% overweight, and 11% obese. Post-operative arrhythmias were observed in 38%. Body mass index was significantly higher in those with arrhythmias (18.8 versus 17.8, p = 0.003). There was a linear relationship between body mass index category and incidence of arrhythmias: underweight 33%, normal 38%, overweight 42%, and obese 45% (p = 0.017 for trend). In multivariate analysis, body mass index category was independently associated with post-operative arrhythmias (p = 0.021), with odds ratio 1.64 in obese patients as compared to normal-weight patients (p = 0.036). In addition, aortic cross-clamp time (OR 1.007, p = 0.002) and maximal vasoactive–inotropic score in the first 48 hours (OR 1.03, p = 0.04) were associated with post-operative arrhythmias.

Conclusion:

Body mass index is independently associated with incidence of post-operative arrhythmias in children after CHD surgery.
The role and efficacy of routine high-sensitivity troponin T screening in paediatric COVID-19
Authors: Ramoğlu Mehmet G. , Karagözlü Selen , Bayram Özlem , Bakhtiyarzada Jeyhun , Aydın Alperen , Vatansever Göksel , Özdemir Halil , Tekin Deniz , Uçar Tayfun , Çiftçi Ergin , Tutar Ercan
Published: January 2022

Objective:

We aimed to evaluate the efficacy and role of high-sensitivity troponin T in children with a confirmed SARS-CoV-2 infection and also the correlation of troponin T levels with symptoms, and echocardiographic findings were analysed.

Methods:

Two hundred and fourteen patients with a confirmed SARS-CoV-2 infection between the dates of 28 March and 15 August 2020 were enrolled in this retrospective single-centre study. Patients with comorbidities and diagnosed as multisystem inflammatory syndrome in children were excluded. Demographic data, clinical and laboratory parameters were evaluated. The patients were classified and compared according to the troponin positivity. The correlation of troponin T with symptoms and echocardiographic findings was analysed.

Results:

The most common symptoms in the whole study group were fever (53.3%) and cough (24.8%). Troponin T levels were elevated in 15 (7%) patients. The most common symptom in patients with troponin positivity was also fever (73.3%). Troponin T positivity was significantly higher in patients under the age of 12 months and troponin T levels were negatively correlated with age. C-reactive protein levels were elevated in 77 (36%) of the patients in the whole group and 7 (46.7%) of 15 patients with troponin positivity. C-reactive protein levels were similar between groups.

Conclusion:

Routine troponin screening does not yield much information in previously healthy paediatric COVID-19 patients without any sign of myocardial dysfunction. Elevated troponin levels may be observed but it is mostly a sign of myocardial injury without detectable myocardial dysfunction in this group of patients.
A systematic review of the evidence supporting post-operative antithrombotic use following cardiopulmonary bypass in children with CHD
Authors: Thompson Elizabeth J. , Foote Henry P. , Li Jennifer S. , Rotta Alexandre T. , Goldenberg Neil A. , Hornik Christoph P.
Published: January 2022

Objectives:

To determine the optimal antithrombotic agent choice, timing of initiation, dosing and duration of therapy for paediatric patients undergoing cardiac surgery with cardiopulmonary bypass.

Methods:

We used PubMed and EMBASE to systematically review the existing literature of clinical trials involving antithrombotics following cardiac surgery from 2000 to 2020 in children 0–18 years. Studies were assessed by two reviewers to ensure they met eligibility criteria.

Results:

We identified 10 studies in 1929 children across three medications classes: vitamin K antagonists, cyclooxygenase inhibitors and indirect thrombin inhibitors. Four studies were retrospective, five were prospective observational cohorts (one of which used historical controls) and one was a prospective, randomised, placebo-controlled, double-blind trial. All included were single-centre studies. Eight studies used surrogate biomarkers and two used clinical endpoints as the primary endpoint. There was substantive variability in response to antithrombotics in the immediate post-operative period. Studies of warfarin and aspirin showed that laboratory monitoring levels were frequently out of therapeutic range (variably defined), and findings were mixed on the association of these derangements with bleeding or thrombotic events. Heparin was found to be safe at low doses, but breakthrough thromboembolic events were common.

Conclusion:

There are few paediatric prospective randomised clinical trials evaluating antithrombotic therapeutics post-cardiac surgery; most studies have been observational and seldom employed clinical endpoints. Standardised, validated endpoints and pragmatic trial designs may allow investigators to determine the optimal drug, timing of initiation, dosing and duration to improve outcomes by limiting post-operative morbidity and mortality related to bleeding or thrombotic events.
The Company Prosodic Deficits Keep Following Right Hemisphere Stroke: A Systematic Review
Authors: Sheppard Shannon M. , Stockbridge Melissa D. , Keator Lynsey M. , Murray Laura L. , Blake Margaret Lehman ,   Right Hemisphere Damage working group, Evidence-Based Clinical Research Committee, Academy of Neurologic Communication Disorders and Sciences
Published: January 2022

Objectives:

The aim of this systematic review was to identify the presence and nature of relationships between specific forms of aprosodia (i.e., expressive and receptive emotional and linguistic prosodic deficits) and other cognitive-communication deficits and disorders in individuals with right hemisphere damage (RHD) due to stroke.

Methods:

One hundred and ninety articles from 1970 to February 2020 investigating receptive and expressive prosody in patients with relatively focal right hemisphere brain damage were identified via database searches.

Results:

Fourteen articles were identified that met inclusion criteria, passed quality reviews, and included sufficient information about prosody and potential co-occurring deficits. Twelve articles investigated receptive emotional aprosodia, and two articles investigated receptive linguistic aprosodia. Across the included studies, receptive emotional prosody was not systematically associated with hemispatial neglect, but did co-occur with deficits in emotional facial recognition, interpersonal interactions, or emotional semantics. Receptive linguistic processing was reported to co-occur with amusia and hemispatial neglect. No studies were found that investigated the co-occurrence of expressive emotional or linguistic prosodic deficits with other cognitive-communication impairments.

Conclusions:

This systematic review revealed significant gaps in the research literature regarding the co-occurrence of common right hemisphere disorders with prosodic deficits. More rigorous empirical inquiry is required to identify specific patient profiles based on clusters of deficits associated with right hemisphere stroke. Future research may determine whether the co-occurrences identified are due to shared cognitive-linguistic processes, and may inform the development of evidence-based assessment and treatment recommendations for individuals with cognitive-communication deficits subsequent to RHD.