Search

Bibliometrics assessing academic productivity play a significant role in neurosurgeon career advancement. This study aimed to evaluate the influence of multiple author profiles on SCOPUS® on neurosurgeon author-level metrics (h-index, document number, citation number).A list of 1671 academic neurosurgeons was compiled through public searches of hospital and faculty websites for the 115 neurosurgical residency training programs. H-index, document number, and citation number for each neurosurgeon were collected using the SCOPUS® algorithm. For surgeons with multiple profiles, total document number and citation number were calculated by summing the results of each profile. Cumulative h-indices were calculated manually. Comparisons were made between surgeons with a single SCOPUS® profile and those with multiple profiles.124 neurosurgeons with multiple profiles were identified. Gender distribution (p=0.47), years in practice (p=0.06), subspecialty (p=0.32), and academic rank (p=0.16) between neurosurgeons with single profiles vs. multiple profiles were similar. The primary profile h-index median was 16 (8-34), combined profiles median was 20 (11-36), and percent loss median was 17.3% (3%-33%) (p0.001). For document number, the primary profile median was 46 (16-127), combined profiles median was 55 (22-148), and percent loss median was 16.2% (7%-36%) (p0.001). For citation number, the primary profile median was 1030 (333-4082), combined profiles median was 1319 (546-4439), and percent loss median was 14.1% (4%-32%) (p0.001).Academic neurosurgeons in the United States with multiple existing profiles on SCOPUS® experience a 17.3%-loss in h-index, a 16.2%-loss in document number, and a 14.1%-loss in citations, heavily undercounting their perceived academic productivity.

OBJECTIVE Concussion incidence is known to be highest in children and adolescents; however, there is conflicting evidence about the effect of age on concussion risk and recovery within the adolescent age range. The heterogeneity of results may be partially due to the use of age groupings based on convenience, making comparisons across studies difficult. This study evaluated the independent effect of age on concussion incidence, severity, and recovery in student-athletes aged 12–18 years using cluster analysis to define groupings. METHODS Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) scores of 11,403 baseline tests and 4922 postinjury tests were used to calculate the incidence rates for adolescent student-athletes grouped into 3 age bands (12–13, 14–15, and 16–18 years of age) on the basis of clustering analysis. The recently created Severity Index was used to compare concussion severity between groups. Follow-up tests for subjects who sustained a concussion were used to evaluate recovery time. The chi-square test and 1-way ANOVA were used to compare differences in demographic characteristics and concussion incidence, severity, and recovery. Multivariable logistic and linear regressions were used to evaluate the independent effects of age on concussion incidence and severity, respectively. Multivariable Cox hazard regression was used to evaluate differences in recovery time. Further analyses were conducted to directly compare findings across studies on the basis of the age groupings used in prior studies. RESULTS Multivariable regression analyses demonstrated that the 14- to 15-year-old age group had a significantly higher concussion incidence than both the 12- to 13-year-old (14- to 15-year-old group vs 12- to 13-year-old group, OR 1.57, 95% CI 1.16–2.17, p = 0.005) and 16- to 18-year-old (16- to 18-year-old group vs 14- to 15-year-old group, OR 0.79, 95% CI 0.69–0.91, p = 0.0008) age groups. There was no difference in incidence between the 12- to 13-year-old and 16- to 18-year-old groups (16- to 18-year group vs 12- to 13-year group, OR 1.26, 95% CI 0.93–1.72, p = 0.15). There were also no differences in concussion severity or recovery between any groups. CONCLUSIONS This study found that concussion incidence was higher during mid-adolescence than early and late adolescence, suggesting a U-shaped relationship between age and concussion risk over the course of adolescence. Age had no independent effect on concussion severity or recovery in the 12- to 13-, 14- to 15-, and 16- to 18-year-old groups. Further analysis of the various age groups revealed that results may vary significantly with minor changes to groupings, which may explain the divergent results in the current literature on this topic. Thus, caution should be taken when interpreting the results of this and all similar studies, especially when groupings are based on convenience.

Academic neurosurgeons with international medical training play a large role in the U.S. neurosurgical workforce. We aimed to compare U.S.-trained neurosurgeons with internationally trained neurosurgeons to reveal differences in subspecialty preferences and training opportunities abroad.We identified 1671 neurosurgeons from 115 Accreditation Council for Graduate Medical Education (ACGME)-accredited neurosurgical residency programs. Data on demographics, institution characteristics, and chosen subspecialty were collected, and faculty were divided based on location of training. Univariate analysis and multivariable logistic regression compared faculty characteristics between training locations.Compared with the U.S. medical school + U.S. residency group, the international medical graduate + U.S. residency group was more likely to subspecialize in oncology/skull base and vascular neurosurgery and complete a fellowship in the United States or internationally (P0.05). The international medical graduate + international residency group was more likely to subspecialize in oncology/skull base neurosurgery, more likely to complete an international fellowship, and less likely to practice general neurosurgery (P0.05). Neurosurgeons in pediatrics, radiosurgery, and vascular subspecialties were more likely to receive fellowship training in any location (P 0.05). Additionally, functional neurosurgeons were more likely to complete fellowships internationally, spinal neurosurgeons were less likely to pursue international fellowships, and peripheral nerve neurosurgeons were more likely to have dual fellowship training in both the United States and abroad (P0.05).International medical training affected subspecialty choice and fellowship training. Internationally trained neurosurgeons more often specialized in oncology and vascular neurosurgery. Functional neurosurgeons were more likely to complete international fellowships, spine neurosurgeons were less likely to complete international fellowships, and peripheral nerve neurosurgeons more often had both U.S. and international fellowships.

High altitude may affect concussion, but prior studies are limited . We tested whether high altitude affects sport-related concussion (SRC) incidence, severity, and recovery.Twenty-five thousand eight hundred fifteen baseline and post-injury Immediate Post-Concussion Assessment and Cognitive Testing results were compiled from Florida and Colorado, low (27 m or 62 m) and high (1,640 m or 1,991 m) altitude locations, respectively. Incidence, severity, and recovery of injury were compared between altitudes.High altitude was associated with increased suspected concussion incidence (adjusted OR, 2.04 [95% CI, 1.86 to 2.24];High altitude was associated with increased suspected concussions and prolonged recovery but less severe initial injury.

Introduction Neurocognitive tests are an integral component of sport-related concussion (SRC) workup. A history of psychiatric illness (HPI) is common among young athletes. Investigations of factors that influence athletes’ baseline neurocognitive function are crucial for an accurate assessment of SRC. Objective In this study, we aim to elucidate the effect of HPI and selective-serotonin reuptake inhibitor (SSRI) medication use on baseline neurocognitive performance in young athletes. Methods We conducted a retrospective cross-sectional study of Immediate Post-Concussion Assessment and Cognitive Testing assessments. A total of 268 athletes with HPI and a control group of 6,364 athletes were included. The outcomes were total symptom score based on post-concussion symptom scale, verbal memory, visual memory, visual motor, reaction time, and impulse control scores with self-reported HPI status and SSRI use. Results Athletes with HPI had an elevated symptom score in both univariate analysis (p Conclusions Clinicians should consider the impact of HPI on baseline neurocognitive performance during the assessment of a suspected SRC. Additional research is required to bolster our findings on SSRI use and ascertain the effects of other drug classes on baseline neurocognitive performance.

OBJECTIVE Concussions in youth sports comprise an estimated 1.6–3.8 million annual injuries in the US. Sex, age, and attention-deficit hyperactivity disorder (ADHD) have been identified as salient risk factors for concussion. This study seeks to evaluate the role of premorbid depression or anxiety (DA), with or without antidepressant use, on the incidence of concussion and the recovery of symptoms and neurocognitive dysfunction after concussion. METHODS Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) was administered to 7453 youth athletes at baseline. Throughout the season, concussions were examined by physicians and athletic trainers, followed by readministration of ImPACT postinjury (PI) and again at follow-up, a median of 7 days PI. Individuals were divided into three categories: 1) unmedicated athletes with DA (DA-only, n = 315), athletes taking antidepressants (DA-meds, n = 81), and those without DA or antidepressant use (non-DA, n = 7039). Concussion incidence was calculated as the total number of concussions per total number of patient-years. The recovery of neurocognitive measures PI was calculated as standardized deviations from baseline to PI and then follow-up in the 5 composite ImPACT scores: symptom score, verbal memory, visual memory, visual motor skills, and reaction time. Univariate results were confirmed with multivariate analysis. RESULTS There was no difference in concussion incidence between the DA-only cohort and the non-DA group. However, the DA-meds group had a significantly greater incidence of concussion than both the DA-only group (OR 2.67, 95% CI 1.88–7.18, p = 0.0001) and the non-DA group (OR 2.19, 95% CI 1.16–4.12, p = 0.02). Deviation from baseline in PI symptom scores was greater among the DA-meds group as compared to the non-DA group (OR 1.14, 95% CI 1.01–1.28, p = 0.03). At follow-up, the deviation from baseline in symptom scores remained elevated among the DA-meds group as compared to the non-DA group (OR 1.62, 95% CI 1.20–2.20, p = 0.002) and the DA-only group (OR 1.87, 95% CI 1.12–3.10, p = 0.02). Deviation from baseline in follow-up verbal memory was also greater among the DA-meds group as compared to both the non-DA group (OR 1.57, 95% CI 1.08–2.27, p = 0.02) and the DA-only group (OR 1.66, 95% CI 1.03–2.69, p = 0.04). CONCLUSIONS Premorbid DA itself does not seem to affect the incidence of concussion or the recovery of symptoms and neurocognitive dysfunction PI. However, antidepressant use for DA is associated with 1) increased concussion incidence and 2) elevated symptom scores and verbal memory scores up to 7 days after concussion, suggesting impaired symptomatic and neurocognitive recovery on ImPACT.

Infiltrative growth is a major cause of high lethality of malignant brain tumors such as glioblastoma (GBM). We show here that GBM cells upregulate guidance receptor Plexin-B2 to gain invasiveness. Deletion of Plexin-B2 in GBM stem cells limited tumor spread and shifted invasion paths from axon fiber tracts to perivascular routes. On a cellular level, Plexin-B2 adjusts cell adhesiveness, migratory responses to different matrix stiffness, and actomyosin dynamics, thus empowering GBM cells to leave stiff tumor bulk and infiltrate softer brain parenchyma. Correspondingly, gene signatures affected by Plexin-B2 were associated with locomotor regulation, matrix interactions, and cellular biomechanics. On a molecular level, the intracellular Ras-GAP domain contributed to Plexin-B2 function, while the signaling relationship with downstream effectors Rap1/2 appeared variable between GBM stem cell lines, reflecting intertumoral heterogeneity. Our studies establish Plexin-B2 as a modulator of cell biomechanics that is usurped by GBM cells to gain invasiveness., Huang et al demonstrate that glioblastoma cells upregulate axon guidance molecule Plexin-B2 to gain invasiveness and that Plexin-B2 promotes glioblastoma cell infiltration along axon fiber tracts in intracranial transplant models by modulating cellular biomechanics.

Background There has been much interest in environmental temperature and race as modulators of Coronavirus disease-19 (COVID-19) infection and mortality. However, in the United States race and temperature correlate with various other social determinants of health, comorbidities, and environmental influences that could be responsible for noted effects. This study investigates the independent effects of race and environmental temperature on COVID-19 incidence and mortality in United States counties. Methods Data on COVID-19 and risk factors in all United States counties was collected. 661 counties with at least 50 COVID-19 cases and 217 with at least 10 deaths were included in analyses. Upper and lower quartiles for cases/100,000 people and halves for deaths/100,000 people were compared with t-tests. Adjusted linear and logistic regression analyses were performed to evaluate the independent effects of race and environmental temperature. Results Multivariate regression analyses demonstrated Black race is a risk factor for increased COVID-19 cases (OR=1.22, 95% CI: 1.09–1.40, P=0.001) and deaths independent of comorbidities, poverty, access to health care, and other risk factors. Higher environmental temperature independently reduced caseload (OR=0.81, 95% CI: 0.71–0.91, P=0.0009), but not deaths. Conclusions Higher environmental temperatures correlated with reduced COVID-19 cases, but this benefit does not yet appear in mortality models. Black race was an independent risk factor for increased COVID-19 cases and deaths. Thus, many proposed mechanisms through which Black race might increase risk for COVID-19, such as socioeconomic and healthcare-related predispositions, are inadequate in explaining the full magnitude of this health disparity.

OBJECTIVEConcussions are a major public health concern, especially for high school and college student athletes. However, there are few prognostic metrics that can accurately quantify concussion severity in order to anticipate recovery time and symptom regression. The Immediate Post-Concussion Assessment and Cognitive Test (ImPACT) is a widely used neurocognitive assessment that can diagnose and track recovery from concussions. This study assesses whether initial ImPACT scores, collected within 48 hours of the injury, can predict persistence of concussion at follow-up.METHODSResults from 6912 ImPACT tests were compiled in 2161 unique student athletes, ages 12–22 years. The authors defined a novel metric, the Severity Index (SI), which is a summation of the number of standard deviations from baseline at the 80% CI for each of the 5 composite scores reported by ImPACT. Patients were binned into groups based on SI (0–3.99, 4–7.99, 8–11.99, 12+) and the relationships between SI groups, composite scores, symptom profiles, and recovery time were characterized using 1-way and 2-way ANOVAs and Kaplan-Meier plots. A logistic regression assessed the value of SI for predicting concussion at follow-up.RESULTSPatients with a higher SI at diagnosis were more likely to still be concussed at their first follow-up (F3,2300 = 93.06; p < 0.0001). Groups with a higher SI also displayed consistently slower recovery over a 42-day period and were more likely to report symptoms in all 4 symptom clusters (Migraine, Cognition, Sleep, and Neuropsychiatric). When controlling for sex, age, number of previous concussions, days between assessments, and location, SI significantly increased the odds of being concussed at follow-up (OR 1.122, 95% CI 1.088–1.142; p < 0.001). This model showed good discrimination with an area under the curve of 0.74.CONCLUSIONSSI is a useful prognostic tool for assessing head injury severity. Concussions with higher initial SI tend to last longer and have broader symptomatic profiles. These findings can help patients and providers estimate recovery based on similar ImPACT score profiles.

Background: Attention deficit hyperactivity disorder (ADHD) may affect concussion risk and recovery in youth athletes. Purpose: To evaluate the association between incidence of concussion and postinjury recovery of symptoms and neurocognitive dysfunction among youth athletes with ADHD and differential stimulant use. Study Design: Cohort study; Level of evidence, 3. Methods: From 2009 to 2019, the authors administered the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) to youth athletes at the beginning of each season. Throughout the season, athletes with concussions were examined and readministered the ImPACT both postinjury and again 7 days after the postinjury administration. These athletes (N = 7453) were divided into those with ADHD on stimulant-based therapy (ADHD+meds; n = 167), those with ADHD not on stimulant-based therapy (ADHD-only; n = 354), and those with no ADHD (non-ADHD; n = 6932). Recovery of neurocognitive dysfunction at postinjury and follow-up was calculated using the ImPACT symptom score, verbal memory, visual memory, visual motor skills, and reaction time (calculated as standardized deviations from baseline). Univariate results were confirmed with multivariate analysis. Results: The ADHD+meds cohort had a lower incidence of concussion (37.3 concussions per 100 patient-years) compared with the ADHD-only group (57.0 concussions per 100 patient-years) (odds ratio [OR], 0.51 [95% CI, 0.37-0.71]; P < .0001) and non-ADHD group (52.8 concussions per 100 patient-years) (OR, 0.50 [95% CI, 0.37-0.67]; P < .0001). At postinjury, ImPACT scores were elevated from baseline to a similar extent in the ADHD+meds cohort compared with the other 2 groups. By follow-up, however, deviations from baseline were lower among the ADHD+meds group compared with the non-ADHD group in verbal memory (OR, 0.46 [95% CI, 0.28-0.76]; P = .002), visual memory (OR, 0.27 [95% CI, 0.10-0.66]; P = .005), and visual motor skills (OR, 0.58 [95% CI, 0.33-0.99]; P = .048). The deviation at follow-up was also lower among the ADHD+meds group compared with the ADHD-only group in visual memory (OR, 0.56 [95% CI, 0.33-0.96]; P = .04) and visual motor skills (OR, 0.42 [95% CI, 0.22-0.81]; P = .01). Conclusion: Stimulant use among youth athletes with ADHD was independently associated with reduced incidence for concussion and lower deviation from baseline in verbal memory, visual memory, and visual motor skills at 7 days postconcussion, suggesting lower neurocognitive impairment at follow-up in this group versus their peers.

Studies investigating seasonality as a risk factor for surgical site infections (SSIs) after spine surgery show mixed results. This study used national data to analyze seasonal effects on spine surgery SSIs.National Surgical Quality Improvement Program data (2011-2018) were queried for posterior cervical fusions (PCFs), cervical laminoplasties, posterior lumbar fusions (PLFs), lumbar laminectomies, and deformity surgeries. Patients aged89 and procedures for tumors, fractures, infections, and nonelective indications were excluded. Patients were divided into warm (admitted April-September) and cold (admitted October-March) seasonal groups. End points were SSIs and reoperations for wound débridement/drainage. Stratified analyses were performed by surgery type and pre-versus postdischarge infections.Overall (N = 208,291), SSIs were more likely in the warm season (odds ratio [OR] 1.15, 95% confidence interval [CI] 1.08-1.23, P0.0001) and for PCFs (OR 1.40, 95% CI 1.08-1.80, P = 0.011), PLFs (OR 1.15, 95% CI 1.04-1.28, P = 0.006), and lumbar laminectomies (OR 1.13, 95% CI 1.03-1.25, P = 0.014). Postdischarge infections were also more likely in the warm season overall (OR 1.15, 95% CI 1.07-1.23, P0.0001) and for PCFs (OR 1.32, 95% CI 1.01-1.73, P = 0.041), PLFs (OR 1.14, 95% CI 1.03-1.27, P = 0.014), and lumbar laminectomies (OR 1.15, CI 1.04-1.27, P = 0.007). In-hospital infections were more likely during the warm season only for PCFs (OR 2.54, 95% CI 1.06-6.10, P = 0.037). Reoperations for infection were more likely during the warm season for PLFs (OR 1.29, 95% CI 1.08-1.54, P = 0.005).PCF, PLF, and lumbar laminectomy performed during the warm season had significantly higher odds of SSI, especially postdischarge SSIs. Reoperation rates for wound management were significantly increased during the warm season for PLFs. Identifying seasonal causes merits further investigation and may influence surgeon scheduling and expectations.

Background: Previously studied risk factors for sports-related concussion in soccer players include sex, age, and player position. However, prior studies were limited in number, they reported conflicting results, and most did not assess initial concussion severity. Purpose/Hypothesis: The purpose of this study was to conduct an in-depth analysis of soccer players across key demographic groups (sex, age, position) for both concussion incidence and severity. It was hypothesized that concussion incidence and severity would be higher among male players, players aged ≥17 years, and goalkeepers. Study Design: Cohort study; Level of evidence, 3. Methods: The authors analyzed baseline and postinjury ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing) scores for athletes aged 12 to 22 years between July 2009 and June 2019. Players were assigned to an age group based on when they had their most recent baseline test. Concussion incidence and concussion severity index were compared using t tests and multivariate logistic regression. Results: For 1189 individuals who reported soccer as their primary sport, 1032 contributed 1754 baseline ImPACT tests (some individuals had multiple baseline tests), whereas 445 individuals were suspected of sustaining a concussion and then referred for a postinjury 1 test. Of these players, 254 (24.6%) had both a baseline and a postinjury test and were analyzed for concussion severity. Linear regression showed that forwards had a lower incidence of ImPACT-proxied concussions than goalkeepers had ( P = .008). Female players had a significantly higher incidence of ImPACT concussions compared with male players (mean, 0.07 [female] vs 0.04 [male] concussions per person-year; P = .05). Players in the ≥17-year age group had a higher incidence of ImPACT concussions than players in the 15- to 16-year age group ( P = .04), although the 15- to 16-year age group had more severe concussions than the ≥17-year age group (mean severity index, 2.91 [age 15-16 years] vs 1.73 [age ≥17 years]; P = .001). Conclusion: Female soccer players experienced a higher incidence of concussion than did male players, and goalkeepers experienced a greater incidence of ImPACT concussions than did forwards. Players of both sexes and all positions in the 15- to 16-year age group showed increased initial concussion severity compared with the ≥17-year age group, despite a lower comparative incidence of ImPACT concussions. Further study is needed to understand whether sex and player position affect concussion severity.

Background: The sex of an athlete is thought to modulate concussion incidence; however, the effects of sex on concussion severity and recovery are less clear. Purpose: To evaluate sex differences in concussion severity and recovery using a large, heterogeneous sample of young student-athletes with the goal of understanding how sex affects concussion outcomes in young athletes. Study Design: Cohort study; Level of evidence, 3. Methods: The Immediate Post-Concussion Assessment and Cognitive Testing results of 11,563 baseline and 5216 postinjury tests were used to calculate the incidence of concussion of adolescent male and female student-athletes ages 12 to 22 years (median, 15 years). The postinjury tests of 3465 male and 1751 female student-athletes evaluated for concussion or head trauma were used to assess differences in the Severity Index (SI) and recovery. Chi-square tests and t tests were used to compare differences in demographic characteristics, incidence, and SI between the 2 cohorts. Multivariable linear, logistic, and Cox proportional hazards regressions were used to control for differences between cohorts in analyses of incidence, SI, and recovery. Results: When we controlled for demographic differences, female participants had higher odds of concussion (odds ratio, 1.62; 95% CI, 1.40-1.86; P < .0001) and higher SI after concussion (β = 0.67; 95% CI, 0.02-1.32; P = .04). This discrepancy in SI was a result of differences in Symptom (2.40 vs 2.94; P < .0001) and Processing Speed (0.91 vs 1.06; P = .01) composite scores between male and female participants, respectively. We found no effect of sex on time to recovery when controlling for initial concussion SI (hazard ratio, 0.94; 95% CI, 0.78-1.12; P = .48). Conclusion: Using large, multisport cohorts, this study provides evidence that female athletes are at higher risk for more concussions and these concussions are more severe, but male and female athletes have similar recovery times when the analysis controls for initial concussion SI.

Surgical expertise does not have a clear definition and is often culturally associated with power, authority, prestige, and case number rather than more objective proxies of excellence. Multiple models of expertise progression have been proposed including the Dreyfus model, however, they all currently require subjective evaluation of skill. Recently, efforts have been made to improve the ways in which surgical excellence is measured and expertise is defined using artificial intelligence, video recordings, and accelerometers. However, these aforementioned methods of assessment are still subjective or indirect proxies of expertise, thus uncovering the neural mechanisms that differentiate expert surgeons from trainees may enhance the objectivity of surgical expertise validation. In fact, some researchers have already suggested that their neural imaging-based expertise classification methods outperform currently used methods of surgical skill certification such as the Fundamentals of Laparoscopic Surgery (FLS) scores. Such imaging biomarkers would not only help better identify the highest performing surgeons, but could also improve residency programs by providing more objective, evidence-based feedback and developmental milestones for those in training and perhaps act as a marker of surgical potential in medical students. Despite the potential advantages of using neural imaging in the assessment of surgical expertise, this field of research remains in its infancy. This systematic review identifies studies that have applied neuromonitoring in assessing surgical skill across levels of expertise. The goals of this review are to identify (1) the strongest neural indicators of surgical expertise, (2) the limitations of the current literature on this subject, (3) the most sensible future directions for further study. We found substantial evidence that surgical expertise can be delineated by differential activation and connectivity in the prefrontal cortex (PFC) across multiple task and neuroimaging modalities. Specifically, novices tend to have greater PFC activation than experts under standard conditions in bimanual and decision-making tasks. However, under high temporal demand tasks, experts had increased PFC activation whereas novices had decreased PFC activation. Common limitations uncovered in this review were that task difficulty was often insufficient to delineate between residents and attending. Moreover, attending level involvement was also low in multiple studies which may also have contributed to this issue. Most studies did not analyze the ability of their neuromonitoring findings to accurately classify subjects by level of expertise. Finally, the predominance of fNIRS as the neuromonitoring modality limits our ability to uncover the neural correlates of surgical expertise in non-cortical brain regions. Future studies should first strive to address these limitations. In the longer term, longitudinal within-subjects design over the course of a residency or even a career will also advance the field. Although logistically arduous, such studies would likely be most beneficial in demonstrating effects of increasing surgical expertise on regional brain activation and inter-region connectivity.

Background Various non-pharmaceutical interventions (NPIs) such as stay-at-home orders and school closures have been employed to limit the spread of Coronavirus disease (COVID-19). This study measures the impact of social distancing policies on COVID-19 transmission in US states during the early outbreak phase to assess which policies were most effective. Methods To measure transmissibility, we analyze the average effective reproductive number (Rt) in each state the week following its 500th case and doubling time from 500 to 1000 cases. Linear and logistic regressions were performed to assess the impact of various NPIs while controlling for population density, GDP, and certain health metrics. This analysis was repeated for deaths with doubling time to 100 deaths with several healthcare infrastructure control variables. Results States with stay-at-home orders in place at the time of their 500th case were associated with lower average Rt the following week compared to states without them (p1 (OR 0.07, 95% CI 0.01-0.37, p=0.004). These states also experienced longer doubling time from 500 to 1000 cases (HR 0.35, 95% CI 0.17-0.72, p=0.004). States in the highest quartile of average time spent at home were also slower to reach 1000 cases than those in the lowest quartile (HR 0.18, 95% CI 0.06-0.53, p=0.002). Conclusions Stay-at-home orders had the largest effect of any policy analyzed. Multivariate analyses with cellphone tracking data suggest social distancing adherence drives these effects. States that plan to scale back such measures should carefully monitor transmission metrics.

Infiltrative growth is a major cause of the high lethality of malignant brain tumors such as glioblastoma (GBM). The study of the contribution of biomechanical processes to GBM invasion is an emerging field. We show here that GBM cells upregulate the guidance receptor Plexin-B2 to gain invasiveness by modulating their biomechanical properties. Deletion of Plexin-B2 in GBM stem cells limited tumor spread and shifted invasion paths from axon fiber tracts to perivascular routes. On a cellular level, Plexin-B2 adjusts cell adhesiveness, migratory responses to different matrix stiffness, and actomyosin dynamics, thus empowering GBM cells to leave stiff tumor bulk and infiltrate softer brain parenchyma. Correspondingly, gene signatures affected by Plexin-B2 were associated with locomotor regulation, matrix interactions, and cellular biomechanics. On a molecular level, the intracellular Ras-GAP domain contributed to Plexin-B2 function, while the signaling relationship with downstream effectors Rap1/2 appeared variable between GBM stem cell lines, reflecting intertumoral heterogeneity. Our studies have established Plexin-B2 as a modulator of cell biomechanics that is usurped by GBM cells to gain invasiveness. Ongoing investigations focus on the regulation of the biomechanical properties of cell membrane and cell actomyosin cortex through plexins that provide GBM cells with the mechanical dynamics to penetrate to restricted space.

OBJECTIVE To examine the effects of recurrent concussions on the incidence, severity, and recovery of significant neurocognitive dysfunction (SND) in young athletes. SETTING Various US youth sports organizations that utilize Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) for baseline and postinjury concussion testing. PARTICIPANTS Data from 11 563 ImPACT baseline evaluations of US student-athletes aged 12 to 22 years were separated into 2 cohorts: subjects reporting 2 or more previous concussions (PC; n = 976 baseline evaluations) at baseline and a control group reporting zero previous concussions (CT; n = 7743 baseline evaluations). Subjects reporting 1 prior concussion were excluded. DESIGN Retrospective cohort. MAIN MEASURES Differences in SND incidence, severity, and recovery between the 2 cohorts were assessed using chi-squared tests, t tests, survival analyses, and multivariate regressions. RESULTS The PC cohort had a higher incidence of head injury leading to ImPACT (436.7 per 1000 person-years vs 194.4 per 1000 person-years, P < .0001) and a higher incidence of SND (140.4 vs 71.8, P < .0001) than controls. However, the Severity Index (SI) demonstrated that SND severity was lower in the PC group (7.55 vs 8.59, P = .04). Adjusted analyses similarly demonstrated that the PC cohort had increased SND incidence (odds ratio = 1.93; 95% CI, 1.61 to 2.31; P < .0001), decreased SI (β = -1.37; 95% CI, -2.40 to -0.34; P = .009), and equivalent recovery (hazard ratio = 0.98; 95% CI, 0.76 to 1.72; P = .90). CONCLUSION Participants with a history of concussion have a higher incidence of SND but present with lower severity SND, which may be a result of increased concussion education or symptom awareness. Recurrent concussion has no significant impact on acute neurocognitive recovery. Together, these results provide evidence against the supposition that a history of concussion increases the severity of future SND.

Intracerebral hemorrhage (ICH) continues to have high morbidity and mortality. Improving ICH outcomes likely requires rapid removal of blood from the parenchyma and restraining edema formation while also limiting further neuronal damage due to the surgical intervention. Minimally invasive surgery (MIS) approaches promise to provide these benefits and have become alluring options for management of ICH. This review describes six MIS techniques for ICH evacuation including craniopuncture, stereotactic aspiration with thrombolysis, endoport-mediated evacuation, endoscope-assisted evacuation, adjunctive aspiration devices, and the surgiscope. The efficacy of each modality is discussed based on current literature. The largest clinical trials have yet to demonstrate definitive effects of MIS intervention on mortality and functional outcomes for ICH. Thus, there is a significant need for further innovation for ICH treatment. Multiple ongoing trials promise to better clarify the potential of the newer, non-thrombolytic MIS techniques.

During morphogenesis, molecular mechanisms that orchestrate biomechanical dynamics across cells remain unclear. Here, we show a role of guidance receptor Plexin-B2 in organizing actomyosin network and adhesion complexes during multicellular development of human embryonic stem cells and neuroprogenitor cells. Plexin-B2 manipulations affect actomyosin contractility, leading to changes in cell stiffness and cytoskeletal tension, as well as cell-cell and cell-matrix adhesion. We have delineated the functional domains of Plexin-B2, RAP1/2 effectors, and the signaling association with ERK1/2, calcium activation, and YAP mechanosensor, thus providing a mechanistic link between Plexin-B2-mediated cytoskeletal tension and stem cell physiology. Plexin-B2-deficient stem cells exhibit premature lineage commitment, and a balanced level of Plexin-B2 activity is critical for maintaining cytoarchitectural integrity of the developing neuroepithelium, as modeled in cerebral organoids. Our studies thus establish a significant function of Plexin-B2 in orchestrating cytoskeletal tension and cell-cell/cell-matrix adhesion, therefore solidifying the importance of collective cell mechanics in governing stem cell physiology and tissue morphogenesis., Biomechanical mechanisms orchestrating stem cell dynamics in development remain unclear. Here the authors show that guidance receptor Plexin-B2 organizes actomyosin contractility, cytoskeletal tension and adhesion during multicellular development of human embryonic stem cells and neuroprogenitor cells.

Semaphorins and plexins are cell surface ligand/receptor proteins that affect cytoskeletal dynamics in metazoan cells. Interestingly, they are also present in Choanoflagellata, a class of unicellular heterotrophic flagellates that forms the phylogenetic sister group to Metazoa. Several members of choanoflagellates are capable of forming transient colonies, whereas others reside solitary inside exoskeletons; their molecular diversity is only beginning to emerge. Here, we surveyed genomics data from 22 choanoflagellate species and detected semaphorin/plexin pairs in 16 species. Choanoflagellate semaphorins (Sema-FN1) contain several domain features distinct from metazoan semaphorins, including an N-terminal Reeler domain that may facilitate dimer stabilization, an array of fibronectin type III domains, a variable serine/threonine-rich domain that is a potential site for O-linked glycosylation, and a SEA domain that can undergo autoproteolysis. In contrast, choanoflagellate plexins (Plexin-1) harbor a domain arrangement that is largely identical to metazoan plexins. Both Sema-FN1 and Plexin-1 also contain a short homologous motif near the C-terminus, likely associated with a shared function. Three-dimensional molecular models revealed a highly conserved structural architecture of choanoflagellate Plexin-1 as compared to metazoan plexins, including similar predicted conformational changes in a segment that is involved in the activation of the intracellular Ras-GAP domain. The absence of semaphorins and plexins in several choanoflagellate species did not appear to correlate with unicellular versus colonial lifestyle or ecological factors such as fresh versus salt water environment. Together, our findings support a conserved mechanism of semaphorin/plexin proteins in regulating cytoskeletal dynamics in unicellular and multicellular organisms.

Introduction: Gender differences in neurocognitive function have been reported over the past few decades. However, multiple studies that report gender differences in Immediate Post-Concussion Assessment and Cognitive Tests composite scores ignore potential confounders which may lead to inaccurate results. Methods: A total of 4829 male and 2477 female baseline Immediate Post-Concussion Assessment and Cognitive Tests from 2009 to 2019 of subjects ages 12–18 years were used to evaluate gender differences in baseline neurocognitive scores and symptom severity ratings. Regression analyses were used to assess the effects of gender on neurocognitive performance at baseline while controlling for a number of potential confounders including symptom burden at the time of testing. Results: Differences in 3 of 5 composite scores as well as severity rating scores were maintained in multivariate analysis. Females had increased Post-Concussion Symptom Scale (β = 3.54, 95% confidence interval, 2.91 to 4.16, P β = 1.82, 95% confidence interval, 1.15 to 2.50, P β = 1.29, 95% confidence interval, 0.85–1.72, P Conclusions: Statistically significant gender differences were found in baseline neurocognitive function. This study clarifies for the first time that gender differences in these neurocognitive domains are not simply an artifact of differences in symptom burden. However, the small effect sizes call into question the clinical relevance of these differences.

OBJECTIVE Given concerns about the potential long-term effects of concussion in young athletes, concussion prevention has become a major focus for amateur sports leagues. Athletes have been known to frequently use anti-inflammatory medications to manage injuries, expedite return to play, and treat concussion symptoms. However, the effects of baseline nonsteroidal anti-inflammatory drug (NSAID) use on the susceptibility to head injury and concussion remain unclear. This study aims to assess the effects of preinjury NSAID use on concussion incidence, severity, and recovery in young athletes. METHODS Data from 25,815 ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing) tests were obtained through a research agreement with ImPACT Applications Inc. Subjects ranged in age from 12 to 22 years old. Those who reported NSAID use at baseline were assigned to one (anti-inflammatory [AI]) cohort, whereas all others were assigned to the control (CT) cohort. Differences in head trauma and concussion incidence, severity, and recovery were assessed using chi-square tests, unpaired t-tests, and Kaplan-Meier plots. RESULTS The CT cohort comprised a higher percentage (p < 0.0001) of males (66.30%) than the AI cohort (44.16%) and had a significantly greater portion of athletes who played football (p = 0.004). However, no statistically significant differences were found between the two cohorts in terms of the incidence of head trauma (CT = 0.489, AI = 0.500, p = 0.9219), concussion incidence (CT = 0.175, AI = 0.169, p = 0.7201), injury severity, or median concussion recovery time (CT = 8, AI = 8, p = 0.6416). In a multivariable analysis controlling for baseline differences between the cohorts, no association was found between NSAID use and concussion incidence or severity. CONCLUSIONS In this analysis, the authors found no evidence that preinjury use of NSAIDs affects concussion risk in adolescent athletes. They also found no indication that preinjury NSAID use affects the severity of initial injury presentation or concussion recovery.

BackgroundPolicymakers have employed various non-pharmaceutical interventions (NPIs) such as stay-at-home orders and school closures to limit the spread of Coronavirus disease (COVID-19). However, these measures are not without cost, and careful analysis is critical to quantify their impact on disease spread and guide future initiatives. This study aims to measure the impact of NPIs on the effective reproductive number (Rt) and other COVID-19 outcomes in U.S. states.MethodsIn order to standardize the stage of disease spread in each state, this study analyzes the weeks immediately after each state reached 500 cases. The primary outcomes were average Rtin the week following 500 cases and doubling time from 500 to 1000 cases. Linear and logistic regressions were performed in R to assess the impact of various NPIs while controlling for population density, GDP, and certain health metrics. This analysis was repeated for deaths with doubling time from 50 to 100 deaths and included several healthcare infrastructure control variables.ResultsStates that had a stay-at-home order in place at the time of their 500th case are associated with lower average Rtthe following week compared to states without a stay-at-home order (p < 0.001) and are significantly less likely to have an Rt>1 (OR 0.07, 95% CI 0.01 to 0.37, p = 0.004). These states also experienced a significantly longer doubling time from 500 to 1000 cases (HR 0.35, 95% CI 0.17 to 0.72, p = 0.004). States in the highest quartile of average time spent at home were also slower to reach 1000 cases than those in the lowest quartile (HR 0.18, 95% CI 0.06 to 0.53, p = 0.002).DiscussionFew studies have analyzed the effect of statewide stay-at-home orders, school closures, and other social distancing measures in the U.S., which has faced the largest COVID-19 case burden. States with stay-at-home orders have a 93% decrease in the odds of having a positive Rtat a standardized point in disease burden. States that plan to scale back such measures should carefully monitor transmission metrics.

ObjectivesCoronavirus disease-19 (COVID-19) has spread rapidly around the world, and many risk factors including patient demographics, social determinants of health, environmental variables, underlying health conditions, and adherence to social distancing have been hypothesized to affect case and death rates. However, little has been done to account for the potential confounding effects of these factors. Using a large multivariate analysis, this study illuminates modulators of COVID-19 incidence and mortality in U.S. counties while controlling for risk factors across multiple domains.MethodsData on COVID-19 and various risk factors in all U.S. counties was collected from publicly available data sources through April 14, 2020. Counties with at least 50 COVID-19 cases were included in case analyses and those with at least 10 deaths were included in mortality models. The 661 counties meeting inclusion criteria for number of cases were grouped into quartiles and comparisons of risk factors were made using t-tests between the highest and lowest quartiles. Similar comparisons for 217 counties were made for above average and below average deaths/100,000. Adjusted linear and logistic regression analyses were performed to evaluate the independent effects of factors that significantly impacted cases and deaths.ResultsUnivariate analyses demonstrated numerous significant differences between cohorts for both cases and deaths. Risk factors associated with increased cases and/or deaths per 100,000 included increased GDP per capita, decreased social distancing, increased age, increased percent Black, decreased percent Hispanic, decreased percent Asian, decreased health, increased poverty, increased diabetes, increased coronary heart disease, increased physical inactivity, increased alcohol consumption, increased tobacco use, and decreased access to primary care. Multivariate regression analyses demonstrated Black race is a risk factor for worse COVID-19 outcome independent of comorbidities, poverty, access to health care, and other mitigating factors. Lower daily temperatures was also an independent risk factor in case load but not deaths.ConclusionsU.S. counties with a higher proportion of Black residents are associated with increased COVID-19 cases and deaths. However, the various suggested mechanisms, such as socioeconomic and healthcare predispositions, did not appear to drive the effect of race in our model. Counties with higher average daily temperatures are also associated with decreased COVID-19 cases but not deaths. Several theories are posited to explain these findings, including prevalence of vitamin D deficiency. Additional studies are needed to further understand these effects.

Background As spine surgery becomes increasingly common in the elderly, frailty has been used to risk stratify these patients. The Hospital Frailty Risk Score (HFRS) is a novel method of assessing frailty using International Classification of Diseases, Tenth Revision (ICD-10) codes. However, HFRS utility has not been evaluated in spinal surgery. Objective To assess the accuracy of HFRS in predicting adverse outcomes of surgical spine patients. Methods Patients undergoing elective spine surgery at a single institution from 2008 to 2016 were reviewed, and those undergoing surgery for tumors, traumas, and infections were excluded. The HFRS was calculated for each patient, and rates of adverse events were calculated for low, medium, and high frailty cohorts. Predictive ability of the HFRS in a model containing other relevant variables for various outcomes was also calculated. Results Intensive care unit (ICU) stays were more prevalent in high HFRS patients (66%) than medium (31%) or low (7%) HFRS patients. Similar results were found for nonhome discharges and 30-d readmission rates. Logistic regressions showed HFRS improved the accuracy of predicting ICU stays (area under the curve [AUC] = 0.87), nonhome discharges (AUC = 0.84), and total complications (AUC = 0.84). HFRS was less effective at improving predictions of 30-d readmission rates (AUC = 0.65) and emergency department visits (AUC = 0.60). Conclusion HFRS is a better predictor of length of stay (LOS), ICU stays, and nonhome discharges than readmission and may improve on modified frailty index in predicting LOS. Since ICU stays and nonhome discharges are the main drivers of cost variability in spine surgery, HFRS may be a valuable tool for cost prediction in this specialty.

Introduction Concussion incidence in the National Football League (NFL) has been shown to generally increase as the season progresses. Yet, there is evidence that suggests that the incidence stagnates or decreases in the final quarter of the season in comparison to the third quarter. This anomaly cannot be explained by any of the known modulators of concussion incidence. However, the fact that the teams start getting eliminated from playoff contention in the fourth quarter of the season may explain this pattern in concussion incidence. This study tests whether there is a difference in concussion incidence in games between teams who are still in the playoff hunt [in the hunt (IH) games] versus games where both teams have had their playoff fate already determined (non-IH games). Methods We obtained details of 166 documented concussions from weeks 13-16 of each of the four NFL seasons from 2012 to 2015 from Public Broadcasting Service's (PBS) Frontline Concussion Watch and matched them to the games in which they occurred. Each game was categorized based on the playoff status [clinched (CL), eliminated (EL), or IH] of the teams playing in the game. Concussion incidence of the game types was compared to each other using a one-way analysis of variance (ANOVA) test and student t-tests. Additionally, concussion incidences at six different player positions in important games were compared to the corresponding incidences in unimportant games. An ordinary least squares regression was used to examine the effects of game importance and plays per game on concussion incidence. Results Concussion incidence in important games (mean = 0.651 ±0.055) did not differ significantly (p: 0.890) from the incidence in unimportant games (mean = 0.623 ±0.143). Instead, plays per game was found to be the primary driver of concussion in the regression analysis (β = 0.01605; p: 0.025). At the position-specific level, running backs (RB) were the only position to demonstrate a significant increase in concussion incidence (p: 0.004) in important games (mean = 0.049 ±0.017) compared to unimportant games (mean = 0.00 ±0.00). Conclusions The results suggest that, in general, players are not more likely to suffer concussions in IH games than in non-IH games. However, RBs may have an increased risk of concussion in games with playoff implications than in games without.

Background Author-level metrics for assessing academic productivity have a significant impact on career advancement in academia. This study determined if 1-year growth rates in author-level metrics among New York (NY) metropolitan area academic neurosurgeons were associated with academic rank and/or years in practice since graduating residency. Methods H-index, document number, and citation number were recorded monthly from March 2018 to March 2019 for academic neurosurgeons from eight NY metropolitan area training programs using the Scopus® abstract and citation database. Subjects with a decrease in any metric or an increase of ≥10 for h-index, ≥20 for documents, or ≥150 for citations between time points were excluded from the analysis. Differences in 1-year metric increases between academic ranks (Assistant Professor, Associate Professor, Professor) were evaluated using ANOVA with Games-Howell post-hoc test. Differences in 1-year metric increases between Assistant Professors with ≤10 and >10 years in practice were evaluated using two-tailed independent samples t-test. Results The final analysis included 80 subjects. Citation growth rates were significantly different between the academic ranks (F2,77 = 13.09, p 10 years in practice. Conclusion Early-career Assistant Professors in academic neurosurgery may exhibit higher productivity than senior faculty, but this finding is qualified by the presence of significant inaccuracies in Scopus® bibliometric profiles.