Baseline ImPACT Composite Scores in Student-Athletes With Attention-Deficit/Hyperactivity Disorder

BACKGROUND

Athletes who are diagnosed with attention-deficit/hyperactivity disorder (ADHD) are at increased risk of concussion compared to other athletes. Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) is a widely used concussion tool, but it relies on pre-injury baseline testing that can be affected by psychiatric conditions. This research aims to determine if there are differences in pre-injury testing composite scores in student-athletes with ADHD compared to those without ADHD diagnosis.

METHODS

We obtained 11,563 pre-season ImPACT assessments of 7,454 student-athletes (ages: 12-22) from 2009 to 2019. After exclusions, there were 6,920 control and 276 ADHD subjects. Multivariable linear regression analyses compared the independent effect of ADHD on the six ImPACT composite score metrics with Bonferroni correction for multiple comparisons with a = 0.008.

RESULTS

Univariate analyses indicated ADHD is associated with more symptoms as measured by the Post-Concussion Symptom Scale (PCSS) (β = 2.67, 95% CI: 1.47-3.87, p < .0001) and worse Impulse Control scores (β = 0.93, 95% CI: 0.33-1.53, p = .002). In multivariate analysis, this association was the same for symptom score (β = 2.48, 95% CI: 1.22-3.74, p < .0001), but Impulse Control was not significantly different after multiple comparison adjustment (β = 0.87, 95% CI: 0.22-1.15, p = .009).

CONCLUSIONS

The ADHD subjects reported worse symptoms at baseline and had worse Impulse Control in univariate analysis, but not multivariate analysis. These results can further guide clinicians in concussion diagnosis and test interpretations for student-athletes with ADHD, considering the symptom burden at baseline.

Complications of Implanted Vagus Nerve Stimulation: A Systematic Review and Meta-analysis

INTRODUCTION

Vagus Nerve Stimulation (VNS) has emerged as a promising tool in ischemic stroke rehabilitation. However, there has been no systematic review summarizing its adverse effects, critical information for patients and providers when obtaining informed consent for this novel treatment. This systematic review and meta-analysis reports the adverse effects of VNS.

METHODS

A systematic review was performed in accordance with PRISMA guidelines to identify common complications after VNS therapy. The search was executed in: Cochrane Central Register of Controlled Trials, Embase, and Ovid MEDLINE. All prospective, randomized controlled trials using implanted VNS therapy in adult patients were eligible for inclusion. Case studies and studies lacking complete complication reports were excluded. Extracted data included technology name, location of implantation, follow-up duration, purpose of VNS, and adverse event rates.

RESULTS

After title-and-abstract screening of 4933 studies, 21 were selected for final inclusion. Across these studies, 1474 patients received VNS implantation. VNS was used as a potential therapy for epilepsy (9), depression (8), anxiety (1), ischemic stroke (1), chronic heart failure (1), and fibromyalgia (1). The 5 most common post-implant adverse events were voice alteration/hoarseness (n=671, 45.5%), paresthesia (n = 233, 15.8%), cough (n = 221, 15.0%), dyspnea (n = 211, 14.3%), and pain (n = 170, 11.5%).

CONCLUSIONS

Complications from VNS are mild and transient, with reduction in severity and number of adverse events with increasing follow-up time. In prior studies, VNS has served as treatment option in several instances of treatment-resistant conditions, such as epilepsy and psychiatric conditions, and its use in stroke recovery and rehabilitation should continue to be explored.

Vagus nerve stimulation for enhanced stroke recovery after intracerebral hemorrhage: illustrative case

BACKGROUND

Randomized controlled trial (RCT) evidence has revealed the efficacy of vagus nerve stimulation (VNS) paired with rehabilitation therapy, over therapy alone, for upper-limb functional recovery after ischemic stroke. However, this technique has not yet been described for the recovery of chronic motor deficits after hemorrhagic stroke.

OBSERVATIONS

Three years after left putaminal intracerebral hemorrhagic stroke with chronic upper-limb functional deficits, a patient was treated with VNS for enhanced stroke recovery. VNS was paired with 6 weeks of in-clinic physical therapy, resulting in upper-limb functional improvement of 14 points on the Fugl-Meyer Assessment Upper Extremity (FMA-UE) index for stroke recovery (maximum score of 66 equating to normal function). This improvement was more than 1 standard deviation above the improvement documented in the first successful RCT of VNS paired with therapy for ischemic stroke (5.0 ± 4.4 improvement on FMA-UE).

LESSONS

VNS is a promising therapy for enhanced recovery after hemorrhagic stroke and may offer greater improvement in function compared to that after ischemic stroke. Improvement in function can occur years after the time of intracerebral hemorrhage.

Clinical Considerations and Outcomes for Spine Surgery Patients with a History of Transplant: A Systematic Scoping Review

OBJECTIVE

The objective of this study was to investigate the perioperative management and outcomes of patients with a prior history of successful transplantation undergoing spine surgery.

METHODS

We searched Medline, Embase, and Cochrane Central Register of Controlled Trials for matching reports in July 2021. We included case reports, cohort studies, and retrospective analyses, including terms for various transplant types and an exhaustive list of key words for various forms of spine surgery.

RESULTS

We included 45 studies consisting of 34 case reports (published 1982-2021), 3 cohort analyses (published 2005-2006), and 8 retrospective analyses (published 2006-2020). The total number of patients included in the case reports, cohort studies, and retrospective analysis was 35, 48, and 9695, respectively. The mean 1-year mortality rate from retrospective analyses was 4.6% ± 1.93%, while the prevalence of perioperative complications was 24%. Cohort studies demonstrated an 8.5% ± 12.03% 30-day readmission rate. The most common procedure performed was laminectomy (38.9%) among the case reports. Mortality after spine surgery was noted for 4 of 35 case report patients (11.4%).

CONCLUSIONS

This is the first systematic scoping review examining the population of transplant patients with subsequent unrelated spine surgery. There is significant heterogeneity in the outcomes of post-transplant spine surgery patients. Given the inherent complexity of managing this group and elevated mortality and complications compared to the general spine surgery population, further investigation into their clinical care is warranted.

Body Mass Index Impacts Indication But Not Outcomes of Thoracic Endovascular Aortic Repair

BACKGROUND

There are limited studies looking at thoracic endovascular aortic repair (TEVAR) outcomes in obese and overweight patients. Our objective was to determine the rate of complications, reintervention, and short-term mortality in normal weight, overweight, and obese patients undergoing TEVAR.

METHODS

Patients undergoing TEVAR at a large tertiary hospital from October 2007 to January 2020 were analyzed. Patients were stratified into 3 cohorts based on body mass index (BMI): normal (18.5-25 kg/m2), overweight (25-30 kg/m2), and obese (>30 kg/m2). Primary outcomes were 30-day and 1-year survival. Intraoperative, in-hospital, and postdischarge complications were assessed as secondary outcomes using the Clavian-Dindo classification system. In addition, reinterventions associated with the index TEVAR procedure as a secondary outcome.

RESULTS

Among 204 patients fitting the study criteria, we identified 65 with normal BMI, 78 overweight, and 61 obese patients. Obese patients were younger than the overweight and normal BMI patients (mean age 62.2 vs. 66.7 vs. 70.7, respectively, P = 0.003). In terms of TEVAR indication, the obese cohort had the highest percentage of patients with type B aortic dissection (36.4%), while the normal BMI cohort had the higher proportion of patients undergoing TEVAR for isolated thoracic aortic aneurysm (63.9%). Intraoperative complications did not significantly differ between cohorts. Postoperatively, in-hospital complications, postdischarge complications and 30-day return to the operative room did not differ significantly between study cohorts. Odds of reintervention did not differ significantly between cohorts, both on univariate and multivariate analysis. Log-rank test of Kaplan Meier analysis revealed no difference in reintervention-free survival (P = 0.22). Thirty-day mortality and 1-year overall survival were similar across cohorts. Both univariate and multivariate logarithmic regression revealed no difference in likelihood of 30-day mortality between the obese and normal cohort.

CONCLUSIONS

There were no measurable differences in complications, reinterventions, or mortality, suggesting that vascular surgeons can perform TEVAR across a spectrum of BMI without compromising outcomes.

The effect of age on baseline neurocognitive performance

OBJECTIVE

Evaluate the independent effect of age on baseline neurocognitive performance.

STUDY DESIGN

Baseline ImPACT scores from tests taken by 7454 athletes aged 12-22 from 2009 to 2019 were split into three age cohorts: 12-14 years (3244), 15-17 years (3732), and 18-22 years (477). Linear regression analyses were used to evaluate the effect of age on ImPACT composite scores while controlling for demographic differences, medication-use, and symptom burden. Significance values have been set at p < 0.05.

RESULTS

Linear regression analyses demonstrated that increased age does not significantly affect symptom score (β = 0.06, p = 0.54) but does improve impulse control (β = -0.45, p < 0.0001), verbal memory (β = 0.23, p = 0.03), visualmotor (β = 0.77, p < 0.0001), and reaction time (β = -0.008, p < 0.0001) scores.  However, age did not have an effect on visual memory scores (β = -0.25, p = 0.07).

CONCLUSIONS

Age was shown to be an independent modifier of impulse control, verbal memory, visual motor, and reaction time scores but not visual memory or symptom scores.  This underscores the previous literature showing developmental differences as age increases among the adolescent athlete population.  This data also indicates the need for repeat neurocognitive baseline testing every other year as baseline scoring is likely to change as athletes become older.

Controlling Pharmaceutical Costs in a Student-Run Free Clinic in a Resource-Limited Patient Setting

Our institution's student-run free clinic has been able to offer medication at no out-of-pocket cost to all patients since it opened in 2004. We have employed two strategies to manage prescription drug costs while simultaneously increasing medication coverage: (1) using Patient Drug Assistance Programs (PDAPs) and (2) developing an institutional-level partnership with pharmaceutical charities for medication subsidization. In this study, we aimed to analyze the financial impact of these measures on the clinic.A query of clinic data over the past 5 years identified 299 active PDAPs, corresponding to 299 fully-subsidized prescriptions. In 2017, there were 35 active PDAPs, increasing to 52 (2018), 62 (2019), and 82 (2020) before a decline to 68 PDAPs in 2021. The company affiliated with the most PDAPs varied annually: GlaxoSmithKline (2017), Lilly (2018, 2019, 2020), and both GlaxoSmithKline and Lilly (2021). The most frequent medications were sitagliptin (2017), insulin (2018, 2019), albuterol (2017, 2018), and dulaglutide (2020, 2021).In addition, data extracted from the private company subsidization program was analyzed for the year 2021. Program membership was $10,000 for institution-wide medication subsidization for all uninsured patients in the hospital system. In total, the clinic was able to acquire 220 medications with a 96% subsidy, corresponding to a direct clinic cost of $2,101.28. Comparatively, the market value of these medications was $52,401.51.Utilization of free drug acquisition programs and partnerships with pharmaceutical charities allowed for an increase in cost-savings and medications provided. Although the process for applying for medication assistance programs is complex, these programs serve as powerful tools for providing medications that may otherwise be unavailable due to cost. Other clinics and healthcare settings with uninsured patients should consider these programs as a means to ease medication cost burden.

Application of the Robotic-Assisted Digital Exoscope for Resection of Posterior Fossa Tumors in Adults: A Series of 45 Cases

BACKGROUND AND OBJECTIVES

Complete safe resection is the goal when pursuing surgical treatment for posterior fossa (PF) tumors. Efforts have led to the development of the exoscope that delineates tumors from non-neoplastic brain. This investigation aims to assess patient outcomes where PF tumor resection is performed with the exoscope by a retromastoid or suboccipital approach.

METHODS

A retrospective analysis was conducted for patients with PF tumors who underwent exoscope resection from 2017 to 2022. Patient demographics, clinical, operative, and outcome findings were collected. Extent of resection studies were also performed. Associations between perioperative data, discharge disposition, progression-free survival (PFS), and overall survival (OS) were evaluated.

RESULTS

A total of 45 patients (22 male patients) with a median age of 57 years were assessed. Eighteen (40%) and 27 patients (60%) were diagnosed with malignant and benign tumors, respectively. Tumor neurovascular involvement was found in 28 patients (62%). Twenty-four (53%) and 20 (44%) tumors formed in the cerebellum and cerebellopontine angle cistern, respectively. One tumor (2%) was found in the cervicomedullary junction. The mean extent of resection was 96.7% for benign and malignant tumors. The PFS and OS rate at 6 months (PFS6, OS6) was 89.7% and 95.5%, respectively. Neurological complications included sensory loss and motor deficit, with 11 patients reporting no postoperative symptoms. Of the neurological complications, 14 were temporary and 9 were permanent.

CONCLUSION

The exoscope is an effective intraoperative visualization tool for delineating PF tumors. In our series, we achieved low postoperative tumor volumes and a high gross total resection rate.

Bibliometric Analysis of International Medical Graduates and Professorship Promotion in Neurosurgery

BACKGROUND

International medical graduates (IMGs) comprise ∼25% of physicians in the United States. Differences in promotion rates from assistant to associate to full professorship based on medical school location have been understudied. We aim to stratify odds of professional advancement by 3 categories: IMG with U.S. residency, IMG with international residency, and U.S. medical with U.S. residency training.

METHODS

We created and queried a database after exclusions of 1334 neurosurgeons including multiple demographic factors: academic productivity and promotion rates. Stratified logistic regression modeled odds of promotion including the variables: decades out of training, Scopus h-index, gender, and training location. Odds ratios (ORs) and 95% confidence intervals (CIs) for each variable were calculated.

RESULTS

Significant predictors of increased associate versus assistant professorship included decades out of training (OR = 2.519 [95% CI: 2.07-3.093], P < 0.0001) and Scopus h-index (OR = 1.085 [95% CI: 1.064-1.108], P < 0.0001) while international medical school with U.S. residency (OR = 0.471 [95% CI: 0.231-0.914], P = 0.0352) was associated with decreased promotion. Significant predictors of associate versus full professorship were decades out of training (OR = 2.781 [95% CI: 2.268-3.444], P < 0.0001) and Scopus h-index (OR = 1.064 [95% CI: 1.049-1.080], P < 0.0001). Attending medical school or residency internationally was not associated with odds of full professorship.

CONCLUSIONS

Time out of residency and Scopus h-index were associated with higher academic rank regardless of career level. Attending medical school internationally with U.S. residency was associated with lower odds of associate professorship promotion over 10 years. There was no relationship between IMG and full professorship promotion. IMGs who attended residency internationally did not have lower promotion rates. These findings suggest it may be harder for IMGs to earn promotion from assistant to associate professor in neurosurgery.

Effects of repetitive head trauma on symptomatology of subsequent sport-related concussion

OBJECTIVE

Adolescent participation in athletics continues to grow, leading to an increasing incidence of sports-related concussion (SRC). The current literature suggests that a greater number of prior concussions positively correlates with a greater number of total symptoms, but the specific concussion-related symptoms are not as well defined. The current study investigated the effects of prior recurrent head injury on the symptom profiles of student-athletes after another suspected concussion.

METHODS

A multicenter database consisting of 25,815 Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) results was filtered for student-athletes aged 12-22 years old who competed in 21 different sports. Patients were separated into 2 cohorts: athletes reporting a single prior concussion (SRC1) and athletes reporting 2 or more prior concussions (SRC2+). Comparisons were assessed for differences in 22 symptoms and 4 symptom clusters at baseline, first postinjury test (PI1), and second postinjury test (PI2) by using univariate and multivariate analyses.

RESULTS

No differences were seen between SRC1 (n = 2253) and SRC2+ (n = 976) at baseline. At PI1, the SRC2+ group (n = 286) had lower severity of headaches (p = 0.04) but increased nervousness (p = 0.042), irritability (p = 0.028), sadness (p = 0.028), visual problems (p = 0.04), and neuropsychiatric symptoms (p = 0.009) compared with SRC1 (n = 529). Multivariate analysis revealed decreased headache severity with increased prior concussion (β = -0.27,95% CI -0.45 to -0.09, p = 0.003). Multivariate analysis at PI2 demonstrated the SRC2+ cohort (n = 130) had increased cognitive (β = 1.22, 95% CI 0.27-2.18, p = 0.012), sleep (β = 0.63, 95% CI 0.17-1.08, p = 0.007), and neuropsychiatric (β = 0.67,95% CI 0.14-1.2,0.014) symptoms compared with SRC1 (n = 292).

CONCLUSIONS

At longitudinal follow-up, patients with a history of recurrent concussions reported greater symptom burden in cognitive, sleep, and neuropsychiatric symptom clusters but not migraine symptoms. This is an important distinction because migraine symptoms are often more easily distinguishable to patients, parents, and physicians. Careful assessment of specific symptoms should be considered in patients with a history of recurrent head injury prior to return to play.

External ventricular drain training in medical students improves procedural accuracy and attitudes towards virtual reality

OBJECTIVE

Neurosurgery residents face a learning curve at the beginning of residency. Virtual reality (VR) training may alleviate challenges through an accessible, reusable, anatomical model.

METHODS

Medical students performed external ventricular drain (EVD) placements in VR to characterize the learning curve from novice to proficient. Distance from catheter to Foramen of Monro and location with respect to ventricle were recorded. Changes in attitudes towards VR were assessed. Neurosurgery residents performed EVD placements to validate proficiency benchmarks. Resident and student impressions of the VR model were compared.

RESULTS

Twenty-one students with no neurosurgical experience and 8 neurosurgery residents participated. Student performance improved significantly from trial 1 to 3 (15 mm [12.1-20.70] vs 9.7 [5.8-15.3], p=.02). Student attitudes regarding VR utility improved significantly post-trial. The distance to Foramen of Monro was significantly shorter for residents than for students in trial 1 (9.05 [8.25-10.73] vs 15 [12.1-20.70], p=.007) and trial 2 (7.45 [6.43-8.3] vs 19.5 [10.9-27.6], p=.002). By trial 3 there was no significant difference (10.1 [8.63-10.95 vs 9.7 [5.8-15.3], p=.62). Residents and students provided similarly positive feedback for VR in resident curricula, patient consent, preoperative practice and planning. Residents provided more neutral-to-negative feedback regarding skill development, model fidelity, instrument movement, and haptic feedback.

CONCLUSIONS

Students showed significant improvement in procedural efficacy which may simulate resident experiential learning. Improvements in fidelity are needed before VR can become a preferred training technique in neurosurgery.

Vagal Nerve Stimulation: A Bibliometric Analysis of Current Research Trends

BACKGROUND

Vagal nerve stimulation (VNS) has become established as an effective tool for the management of various neurologic disorders. Consequently, a growing number of VNS studies have been published over the past four decades. This study presents a bibliometric analysis investigating the current trends in VNS literature.

MATERIALS AND METHODS

Using the Web of Science collection data base, a search was performed to identify literature that discussed applications of VNS from 2000 to 2021. Analysis and visualization of the included literature were completed with VOSviewer.

RESULTS

A total of 2895 publications were identified. The number of articles published in this area has increased over the past two decades, with the most citations (7098) occurring in 2021 and the most publications (270) in 2020. The h-index, i-10, and i-100 were 97, 994, and 91, respectively, with 17.0 citations per publication on average. The highest-producing country and institution of VNS literature were the United States and the University of Texas, respectively. The most productive journal was Epilepsia. Epilepsy was the predominant focus of VNS research, with the keyword "epilepsy" having the greatest total link strength (749) in the keyword analysis. The keyword analysis also revealed two major avenues of VNS research: 1) the mechanisms by which VNS modulates neural circuitry, and 2) therapeutic applications of VNS in a variety of diseases beyond neurology. It also showed a significant prevalence of noninvasive VNS research. Although epilepsy research appears more linked to implanted VNS, headache and depression specialists were more closely associated with noninvasive VNS.

CONCLUSION

VNS may serve as a promising intervention for rehabilitation beyond neurologic applications, with an expanding base of literature over the past two decades. Although epilepsy researchers have produced most current literature, other fields have begun to explore VNS as a potential treatment, likely owing to the rise of noninvasive forms of VNS.

External Ventricular Drain Placement Teleproctoring Using a Novel Camera-Projector Navigation System: A Proof-of-Concept Study

INTRODUCTION

Teleproctoring is an emerging method of bedside clinical teaching, but its feasibility is limited by available technologies. The use of novel tools that incorporate 3D environmental information and feedback may offer better bedside teaching options for neurosurgical procedures, including external ventricular drain placement.

METHODS

A platform utilizing a camera-projector system was employed for proctoring medical students on placing external ventricular drains on an anatomic model as a proof-of-concept study. 3D depth information of the model and the surrounding environment was captured by the camera system and provided to the proctor who was able to make projected annotations in a geometrically compensated manner onto the head model in real-time. Medical students were randomized to identify Kocher's point on the anatomic model with or without the navigation system. Time and accuracy to identify Kocher's point were measured as a proxy for determining the effectiveness of the navigation-proctoring system.

RESULTS

20 students were enrolled in the study. Those in the experimental group identified Kocher's point an average of 130 seconds faster than the control group (p < 0.001). The mean diagonal distance from Kocher's point was 8.0 ± 4.29mm in the experimental group compared to 23.6 ± 21.98mm in the control group (p = 0.053). 70% of subjects randomized to the camera-projector system arm were accurate to within 1cm of Kocher's point compared to 40% in the control arm (p>0.05).

CONCLUSIONS

Camera-projector systems for bedside procedure proctoring and navigation is a viable and valuable technology. This study demonstrated its viability in external ventricular drain placements as a proof-of-concept, but the versatility of this technology indicates that that it may be useful for a variety of even more complex neurosurgical procedures.

The Effect of Multiple Scopus Profiles on the Perceived Academic Productivity of Neurosurgeons in the United States

OBJECTIVE

Bibliometrics assessing academic productivity plays a significant role in neurosurgeons' 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).

METHODS

A list of 1671 academic neurosurgeons was compiled through public searches of hospital and faculty websites for 115 neurosurgical residency training programs. The 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 results of each profile. Cumulative h-indices were calculated manually. Comparisons were made between surgeons with a single Scopus profile and surgeons with multiple profiles.

RESULTS

A total of 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 a single profile versus multiple profiles were similar. Primary profile h-index median was 16 (interquartile range [IQR]: 8-34), combined profiles median was 20 (IQR: 11-36), and percent loss median was 17.3% (IQR: 3%-33%) (P < 0.001). For document number, primary profile median was 46 (IQR: 16-127), combined profiles median was 55 (IQR: 22-148), and percent loss median was 16.2% (IQR: 7%-36%) (P < 0.001). For citation number, primary profile median was 1030 (IQR: 333-4082), combined profiles median was 1319 (IQR: 546-4439), and percent loss median was 14.1% (IQR: 4%-32%) (P < 0.001).

CONCLUSIONS

U.S. academic neurosurgeons 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.

Exosome-Based Therapy for Ischemic Stroke: A Bibliometric Analysis of Current Trends and Future Directions

BACKGROUND

Stroke is a leading cause of mortality and disability worldwide. Exosomes, or small extracellular vesicles with signaling properties, have recently been identified as novel mechanisms for stroke treatment. This study aims to use bibliometric techniques to identify current research trends and future directions of exosome-based stroke therapy.

METHODS

The Web of Science Core Collection was searched using terms that included "exosome" and all stroke types. Bibliometric data, including authors, publication years, citations, countries/regions, institutions, journals, and Keywords Plus, were extracted directly from the Web of Science Core Collection. Keywords were mapped using VOSviewer.

RESULTS

From 2010 to 2021, 424 documents were identified with a total of 12,708 citations. The number of publications increased yearly from 2012 to 2021, the majority of which were research and review articles. China and the United States produced the most publications with Henry Ford Hospital and Oakland University serving as the 2 most highly published research institutions. Documents were published most frequently in the journal Stroke. Keywords Plus analyses revealed 3 main research areas: exosomes as pathogenic mediators, biomarkers, and treatments of stroke. Ischemic stroke was the most prevalent type of stroke included in these studies.

CONCLUSIONS

Using bibliometric techniques, this study identified a current and growing interest in the research of exosomes in stroke, particularly in their pathogenic, biomarker, and potential minimally invasive therapeutic properties. Given the high prevalence of ischemic stroke in the current literature, further characterization of exosomes in other stroke types, such as intracerebral hemorrhage, emerges as a future direction for this field of research.

Novel Grading Scales for Static and Flexion-Extension Magnetic Resonance Imaging in Patients with Cervical Spondylotic Myelopathy

BACKGROUND

Flexion-extension magnetic resonance imaging (MRI) has potential to identify cervical pathology not detectable on conventional static MRI. Our study evaluated standard quantitative and novel subjective grading scales for assessing the severity of cervical spondylotic myelopathy in dynamic sagittal MRI as well as in static axial and sagittal images.

METHODS

Forty-five patients underwent both conventional and flexion-extension MRI prior to anterior cervical discectomy and fusion from C4 through C7. In addition to measuring Cobb angles and cervical canal diameter, grading scales were developed for assessment of vertebral body translation, loss of disc height, change in disc contour, deformation of cord contour, and cord edema. Data were collected at all levels from C2-C3 through C7-T1. Variations in measurements between cervical levels and from flexion through neutral to extension were assessed using Mann-Whitney, Kruskal-Wallis, and two-way ANOVA tests.

RESULTS

Cervical canal diameter, vertebral translation, and posterior disc opening changed significantly from flexion to neutral to extension positions (P < 0.01). When comparing operative versus nonoperative cervical levels, significant differences were found when measuring sagittal cervical canal dimensions, vertebral translation, and posterior disc opening (P < 0.01). Degenerative loss of disc height, disc dehydration, deformation of ventral cord contour, and cord edema were all significantly increased at operative levels versus nonoperative levels (P < 0.01).

CONCLUSIONS

Flexion-extension MRI demonstrated significant changes not available from conventional MRI. Subjective scales for assessing degenerative changes were significantly more severe at levels with operative cervical spondylotic myelopathy. The utility of these scales for planning surgical intervention at specific and adjacent levels is currently under investigation.

Seasonal Effects on Postoperative Complications After Spinal Surgery: A National Database Analysis

OBJECTIVE

To investigate the role of seasonality on postoperative complications after spinal surgery.

METHODS

Data were obtained from the American College of Surgeons National Surgical Quality Improvement Program database from 2011 to 2018. Current Procedural Terminology codes were used to identify the following procedures: posterior cervical decompression and fusion, cervical laminoplasty, posterior lumbar fusion, lumbar laminectomy, and spinal deformity surgery. The database was queried for deep vein thrombosis (DVT), pulmonary embolism, pneumonia, sepsis, septic shock, Clostridium difficile infection, stroke, cardiac arrest, myocardial infarction, urinary tract infection (UTI), and early unplanned hospital readmission (readmission). Warm season was defined as April-September, whereas cold season was defined as October-March. Statistical analysis included computing overall complication rates and comparison between seasons using univariate analysis and multivariable logistic regression.

RESULTS

A total of 208,291 individuals underwent spinal surgery from 2011 to 2018. There was a statistically significant increase in UTI (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.07-1.26; P = 0.0002) and readmission (OR, 1.06; 95% CI, 1.02-1.11, P = 0.007) in the warm season compared with the cold season. An investigation into the July effect showed increases in DVT (OR, 1.24; 95% CI, 1.03-1.48; P = 0.020) and thromboembolic events (OR 1.17; 95% CI, 1.01-1.35; P = 0.032) in July-September compared with the preceding 3 months.

CONCLUSIONS

The results showed a higher incidence of UTI and readmission among spine surgery patients in the warm season and a higher incidence of DVT and thromboembolic events from July to September. In both cases, the effect of seasonality is statistically significant, but the absolute difference is small and may not suggest policy changes.

Exosomes in subarachnoid hemorrhage: A scoping review

INTRODUCTION

Vasospasm is a common complication following subarachnoid hemorrhage (SAH), causing increased ischemia and tissue injury, and is implicated as a major risk factor for poor outcomes. The success of current treatments for vasospasm is limited, with limited efficacy and unclear clinical benefits. Exosomes, vesicles that carry small molecules such as miRNA, have been theorized as a potential vasospasm treatment. In this study, we aim to survey the current literature discussing the role of exosomes in the setting of SAH.

METHODS

Following PRISMA guidelines, we performed a scoping review evaluating the role of exosomes in the treatment of SAH. The search was conducted using PubMed and Scopus, and all original research papers studying exosomal profiles of SAH research subjects or SAH therapy were eligible for inclusion.

RESULTS

After screening and full text review, seven papers were selected for final inclusion. Of these, two studies analyzed the expression profile of endogenous exosomes after SAH. Four papers identified and characterized miRNA-based exosomal therapies to attenuate early brain injury (EBI) after SAH. One paper discussed the role of protein overexpression in exosome delivery of miRNA for EBI after SAH. Interestingly, all identified papers studying exosomal therapy demonstrated anti-apoptotic or anti-inflammatory effects of miRNA exosomes acting via the BDNF/TrkB/CREB or HDAC3/NF-κB pathways.

CONCLUSION

Identified studies demonstrate potential neuroprotective benefits of miRNA-based exosomal treatment of EBI and SAH. Findings warrant further research investigating the anti-inflammatory and anti-apoptotic role of exosomal miRNA delivery in SAH models, specifically targeting the common pathway identified by the authors.

Accuracy of artificial intelligence for the detection of intracranial hemorrhage and chronic cerebral microbleeds: a systematic review and pooled analysis

BACKGROUND

Artificial intelligence (AI)-driven software has been developed and become commercially available within the past few years for the detection of intracranial hemorrhage (ICH) and chronic cerebral microbleeds (CMBs). However, there is currently no systematic review that summarizes all of these tools or provides pooled estimates of their performance.

METHODS

In this PROSPERO-registered, PRISMA compliant systematic review, we sought to compile and review all MEDLINE and EMBASE published studies that have developed and/or tested AI algorithms for ICH detection on non-contrast CT scans (NCCTs) or MRI scans and CMBs detection on MRI scans.

RESULTS

In total, 40 studies described AI algorithms for ICH detection in NCCTs/MRIs and 19 for CMBs detection in MRIs. The overall sensitivity, specificity, and accuracy were 92.06%, 93.54%, and 93.46%, respectively, for ICH detection and 91.6%, 93.9%, and 92.7% for CMBs detection. Some of the challenges encountered in the development of these algorithms include the laborious work of creating large, labeled and balanced datasets, the volumetric nature of the imaging examinations, the fine tuning of the algorithms, and the reduction in false positives.

CONCLUSIONS

Numerous AI-driven software tools have been developed over the last decade. On average, they are characterized by high performance and expert-level accuracy for the diagnosis of ICH and CMBs. As a result, implementing these tools in clinical practice may improve workflow and act as a failsafe for the detection of such lesions. REGISTRATION-URL: https://www.crd.york.ac.uk/prospero/ Unique Identifier: CRD42021246848.

Evaluation of differences across age groups in the incidence, severity, and recovery of concussion in adolescent student-athletes from 2009 to 2019

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.

Portable stroke detection devices: a systematic scoping review of prehospital applications

BACKGROUND

The worldwide burden of stroke remains high, with increasing time-to-treatment correlated with worse outcomes. Yet stroke subtype determination, most importantly between stroke/non-stroke and ischemic/hemorrhagic stroke, is not confirmed until hospital CT diagnosis, resulting in suboptimal prehospital triage and delayed treatment. In this study, we survey portable, non-invasive diagnostic technologies that could streamline triage by making this initial determination of stroke type, thereby reducing time-to-treatment.

METHODS

Following PRISMA guidelines, we performed a scoping review of portable stroke diagnostic devices. The search was executed in PubMed and Scopus, and all studies testing technology for the detection of stroke or intracranial hemorrhage were eligible for inclusion. Extracted data included type of technology, location, feasibility, time to results, and diagnostic accuracy.

RESULTS

After a screening of 296 studies, 16 papers were selected for inclusion. Studied devices utilized various types of diagnostic technology, including near-infrared spectroscopy (6), ultrasound (4), electroencephalography (4), microwave technology (1), and volumetric impedance spectroscopy (1). Three devices were tested prior to hospital arrival, 6 were tested in the emergency department, and 7 were tested in unspecified hospital settings. Median measurement time was 3 minutes (IQR: 3 minutes to 5.6 minutes). Several technologies showed high diagnostic accuracy in severe stroke and intracranial hematoma detection.

CONCLUSION

Numerous emerging portable technologies have been reported to detect and stratify stroke to potentially improve prehospital triage. However, the majority of these current technologies are still in development and utilize a variety of accuracy metrics, making inter-technology comparisons difficult. Standardizing evaluation of diagnostic accuracy may be helpful in further optimizing portable stroke detection technology for clinical use.

Effects of a history of headache and migraine treatment on baseline neurocognitive function in young athletes

Objective/background

Despite the prevalence of concussions in young athletes, the impact of headaches on neurocognitive function at baseline is poorly understood. We analyze the effects of a history of headache treatment on baseline ImPACT composite scores in young athletes.

Methods

A total of 11,563 baseline ImPACT tests taken by 7,453 student-athletes ages 12-22 between 2009 and 2019 were reviewed. The first baseline test was included. There were 960 subjects who reported a history of treatment for headache and/or migraine (HA) and 5,715 controls (CT). The HA cohort included all subjects who self-reported a history of treatment for migraine or other type of headache on the standardized questionnaire. Chi-squared tests were used to compare demographic differences. Univariate and multivariate regression analyses were used to assess differences in baseline composite scores between cohorts while controlling for demographic differences and symptom burden.

Results

Unadjusted analyses demonstrated that HA was associated with increased symptoms (β=2.30, 95% CI: 2.18-2.41, p<.0001), decreased visual memory (β=-1.35, 95% CI: -2.62 to -0.43, p=.004), and increased visual motor speed (β=0.71, 95% CI: 0.23-1.19, p=.004) composite scores. Baseline scores for verbal memory, reaction time, and impulse control were not significantly different between cohorts. Adjusted analyses demonstrated similar results with HA patients having greater symptom burden (β=1.40, 95% CI: 1.10-1.70, p<.0001), lower visual memory (β=-1.25, 95% CI: -2.22 to -0.27, p=.01), and enhanced visual motor speed (β=0.60, 95% CI: 0.11-1.10, p=.02) scores.

Conclusion

HA affected symptom, visual motor speed, and visual memory ImPACT composite scores. Visual memory scores and symptom burden were significantly worse in the HA group while visual motor speed scores were better, which may have been due to higher stimulant use in the HA group. The effects of HA on visual motor speed and visual memory scores were independent of the effects of the increased symptom burden.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01432-w.

Subspecialty and Training Preferences for United States Neurosurgery Faculty with International Training

BACKGROUND

Academic neurosurgeons with international medical training play a large role in the US neurosurgical workforce. We aim to compare US trained with internationally trained neurosurgeons to uncover differences in subspecialty preferences and training opportunities abroad.

METHODS

1671 neurosurgeons from 115 ACGME accredited neurosurgical residency programs were identified in 2020. 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.

RESULTS

Compared to the US Medical School+US Residency group, the international medical graduate (IMG)+US residency group was more likely to subspecialize in oncology/skull base and vascular neurosurgery and complete a fellowship in the US or internationally (p<0.05). The IMG+International residency group was more likely to subspecialize in oncology/skull base, more likely to do an international fellowship, and less likely to practice general neurosurgery (p<0.05). 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 US and abroad (p<0.05).

CONCLUSIONS

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 US and international fellowships.

Abstract TP106: Diagnostic Capability Of An Emerging Portable Stroke Detection Device In Clinical Practice

Introduction: Portable stroke detection devices may serve as important tools in stroke triage. With the capacity to differentiate stroke type and severity, these devices may allow for reductions in time-to-treatment, leading to improved patient outcomes in time sensitive neurologic diseases. One such device is the Cerebrotech Visor, an FDA-approved technology that aims to identify severe stroke by detecting bioimpedance asymmetry in brain tissue across a wide range of electromagnetic wavelengths. This study aims to evaluate the ability of this device to detect stroke types in a pilot set of patients presenting as acute stroke codes.

Methods: Trained operators performed scans using the Visor during stroke codes from November 2020 to July 2021 on eligible patients. Clinical and radiologic characteristics as well as the Visor output, an algorithmically derived asymmetry score, were prospectively entered into a quality assurance database. CT findings and subsequent physician notes were used to classify patient stroke type and severity. T-tests were performed to assess the ability of the Visor score to detect various types of CT-confirmed stroke.

Results: Seventy-eight patients were included and scanned. Using CT results, patients were classified into categories: ischemic stroke (IS) (16), intracerebral hemorrhage (ICH) (12), subdural hematoma (2), brain tumor (0), prior neurosurgical procedure (0), intraventricular hemorrhage (2), hydrocephalus (1), and no findings (49), with 3 patients experiencing a combination of these neurological findings. Visor scores for IS and ICH were individually compared to the cohort without IS and ICH, respectively. A t-test comparing patients with IS to the rest of the cohort showed significantly higher Visor scores (9.66 vs 7.13, p = 0.014). Although patients with ICH also had higher Visor scores, the difference was not statistically significant (8.16 vs 7.55, p = 0.30).

Conclusion: The Cerebrotech Visor was able to differentiate between IS and non-IS with the current bioimpedance asymmetry-based device algorithm. Future studies aim to increase patient cohort size and use this patient-centered data to develop a machine learning algorithm to better differentiate other stroke types with this bioimpedance technology.

Abstract WP51: Portable Stroke Detection In A Comprehensive Stroke Center: Pilot Deployment Of The Cerebrotech Visor

Introduction: Stroke is a leading cause of morbidity and mortality, with worse outcomes associated with increased time-to-treatment. As stroke subtypes are currently not confirmed until in-hospital imaging, portable stroke detection technology can reduce time to stroke diagnosis and treatment. The Cerebrotech Visor is an FDA-approved portable bioimpedance device that has been shown to differentiate severe stroke from minor stroke. This study aims to evaluate the accuracy of the Visor device in severe stroke detection in patients presenting as acute stroke codes.

Methods: All patients presenting to the emergency department and receiving a stroke code at two hospitals from November 2020 to July 2021 were eligible. Trained operators completed device scans on eligible patients. The device functioned by detecting asymmetry in bioimpedance over a range of wavelengths to provide an algorithmically derived score. Visor scores, time to scan, and in-hospital imaging findings were recorded prospectively in a quality assurance database. T-tests were performed.

Results: Eighty-seven patient scans were attempted. Patients without successful scans, due to reasons like patient motion and low patient tolerance of the device, were excluded. Patients with underlying diseases noted in scan comments that would alter the baseline brain landscape, such as advanced dementia, were also excluded. In total, 78 patients were included, with a mean age of 69.2 years (σ = 14.3). Scans were most frequently performed in the emergency department and took an average of 105.6 seconds. Using CT data, patients were divided into two groups based on normal or abnormal CT findings. Patients with abnormal CT results have significantly higher Visor scores (8.56 vs 7.11, p = 0.0495).

Conclusion: The Cerebrotech Visor is a portable stroke detection device with the ability to detect alterations in brain bioimpedance in under 2 minutes. Though a large-scale validation study must be performed to assess the accuracy of the device to diagnose specific neurologic conditions, this pilot series of patients undergoing assessment as acute stroke codes demonstrates that this device may provide a rapid method for the in-hospital triage of severe stroke, reducing time-to-treatment for these patients.

Risk Factors for Opioid Utilization in Patients with Intracerebral Hemorrhage

BACKGROUND

Headache is a common presenting symptom of intracerebral hemorrhage (ICH) and often necessitates treatment with opioid medications. However, opioid prescribing patterns in patients with ICH are not well described. We aimed to characterize the prevalence and risk factors for short and longer-term opioid use in patients with ICH.

METHODS

We conducted a retrospective cohort study using data from a single-center registry of patients with nontraumatic ICH. This registry included data on demographics, ICH-related characteristics, and premorbid, inpatient, and postdischarge medications. After excluding patients who died or received end-of-life care, we used multivariable regression models adjusted for premorbid opioid use to determine demographic and ICH-related risk factors for inpatient and postdischarge opioid use.

RESULTS

Of 468 patients with ICH in our cohort, 15% (n = 70) had premorbid opioid use, 53% (n = 248) received opioids during hospitalization, and 12% (n = 53) were prescribed opioids at discharge. The most commonly used opioids during hospitalization were fentanyl (38%), oxycodone (30%), morphine (26%), and hydromorphone (7%). Patients who received opioids during hospitalization were younger (univariate: median [interquartile range] 64 [53.5-74] vs. 76 [67-83] years, p < 0.001; multivariable: odds ratio [OR] 0.96 per year, 95% confidence interval [CI] 0.94-0.98) and had larger ICH volumes (univariate: median [interquartile range] 10.1 [2.1-28.6] vs. 2.7 [0.8-9.9] cm³, p < 0.001; multivariable: OR 1.05 per cm³, 95% CI 1.03-1.08) than those who did not receive opioids. All patients who had external ventricular drain placement and craniotomy/craniectomy received inpatient opioids. Additional risk factors for increased inpatient opioid use included infratentorial ICH location (OR 4.8, 95% CI 2.3-10.0), presence of intraventricular hemorrhage (OR 3.9, 95% CI 2.2-7.0), underlying vascular lesions (OR 3.0, 95% CI 1.1-8.1), and other secondary ICH etiologies (OR 7.5, 95% CI 1.7-32.8). Vascular lesions (OR 4.0, 95% CI 1.3-12.5), malignancy (OR 5.0, 95% CI 1.5-16.4), vasculopathy (OR 10.0, 95% CI 1.8-54.2), and other secondary etiologies (OR 7.2, 95% CI 1.8-29.9) were also risk factors for increased opioid prescriptions at discharge. Among patients who received opioid prescriptions at discharge, 43% (23 of 53) continued to refill their prescriptions at 3 months post discharge.

CONCLUSIONS

Inpatient opioid use in patients with ICH is common, with some risk factors that may be mechanistically connected to primary headache pathophysiology. However, the lower frequency of opioid prescriptions at discharge suggests that inpatient opioid use does not necessarily lead to a high rate of long-term opioid dependence in patients with ICH.

Modeling the Clinical Implications of Andexanet Alfa in Factor Xa Inhibitor-Associated Intracerebral Hemorrhage

BACKGROUND AND OBJECTIVES

Andexanet alfa was recently approved as a reversal agent for the factor Xa inhibitors (FXais) apixaban and rivaroxaban, but its impact on long-term outcomes in FXai-associated intracerebral hemorrhage (ICH) is unknown. We aimed to explore potential clinical implications of andexanet alfa in FXai-associated ICH in this simulation study.

METHODS

We simulated potential downstream implications of andexanet alfa across a range of possible hemostatic effects using data from a single center that treats FXai-associated ICH with prothrombin complex concentrate (PCC). We determined baseline probabilities of inadequate hemostasis across patients taking FXai and those not taking FXai via multivariable regression models and then determined the probabilities of unfavorable 3-month outcome (modified Rankin Scale score 4-6) using models comprising established predictors and each patient's calculated probability of inadequate hemostasis. We applied bootstrapping with model parameters from this derivation cohort to simulate a range of hemostatic improvements and corresponding outcomes and then calculated absolute risk reduction (relative to PCC) and projected number needed to treat (NNT) to prevent 1 unfavorable outcome.

RESULTS

Training models using real-world patients (n = 603 total, 55 on FXai) had good accuracy in predicting inadequate hemostasis (area under the curve [AUC] 0.78) and unfavorable outcome (AUC 0.78). Inadequate hemostasis was strongly associated with unfavorable outcome (odds ratio 4.5, 95% confidence interval [CI] 2.0-9.9) and occurred in 11.4% of patients taking FXai. Across simulated patients taking FXai comparable to those in A Study in Participants With Andexanet Alfa, a Novel Antidote to the Anticoagulation Effects of Factor Xa Inhibitors (ANNEXA-4) study, predicted absolute risk reduction of unfavorable outcome was 4.9% (95% CI 1.3%-7.8%) when the probability of inadequate hemostasis was reduced by 33% and 7.4% (95% CI 2.0%-11.9%) at 50% reduction, translating to projected NNT of 21 (cumulative cost $519,750) and 14 ($346,500), respectively.

DISCUSSION

Even optimistic simulated hemostatic effects suggest that the costs and potential benefits of andexanet alfa should be carefully considered. Placebo-controlled randomized trials are needed before its use can definitively be recommended.

Bibliometric Evaluation of U.S. Neurosurgery Subspecialties and Academic Rank Using RCR Index

INTRODUCTION

Academic productivity, a key feature of academic neurosurgery, has been linked to academic rank, subspecialty, and institutional rank. Relative Citation Ratio (RCR) has emerged as a new metric of scholarly output that can make field-normalized comparisons between researchers, a feature unavailable in prior metrics such as h-index. Here we evaluate the influence of academic rank and neurosurgical subspecialties on RCR scores.

METHODS

We identified 1640 academic neurosurgeons from 115 ACGME-accredited programs in the United States, along with their neurosurgical specialty and demographic information, using publicly available data. Mean RCR (m-RCR) and weighted RCR (w-RCR) for each neurosurgeon were queried from the iCite database, which included publications from 2002-2020. m-RCR and w-RCR scores were compared across subspecialties and academic rank using multivariable regression while controlling for demographic factors.

RESULTS

Multivariable analysis indicated that academic neurosurgeons in general neurosurgery (P = 0.039) and pediatric neurosurgery (P = 0.003) had lower m-RCR scores than their peers in other subspecialties. w-RCR did not differ significantly among subspecialties. Higher academic rank was associated with increased m-RCR (P < 0.05) and w-RCR scores (P < 0.0001).

CONCLUSIONS

Professors have a higher m-RCR score relative to assistant professors, while general and pediatric neurosurgery were linked to lower m-RCR values. Although neurosurgical subspecialty choice did not influence w-RCR, a higher w-RCR score corresponded to a higher academic rank. Overall, the RCR metric can be utilized for field-normalized comparisons of faculty who differ in academic rank and subspecialty.

Impact of Psychiatric Illnesses and Selective Serotonin Reuptake Inhibitor Medications on Baseline Neurocognitive Testing

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 < .0001) and multivariate analysis (p < .0001). HPI influence on visual memory score was not robust to multivariate analysis (p = .24). Athletes with HPI who reported SSRI medication use had the same baseline neurocognitive performance as other athletes with HPI. HPI influences athletes' baseline neurocognitive performance by elevating symptom scores. HPI does not alter any of the objective neurocognitive composite scores in contrast to previous work.

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.

Gender Disparities in Stroke Code Activation in Patients with Intracerebral Hemorrhage

OBJECTIVES

Routine implementation of protocol-driven stroke "codes" results in timelier and more effective acute stroke management. However, it is unclear if patient demographics contribute to disparities in stroke code activation. We aimed to explore these demographic factors in a retrospective cohort study of patients with intracerebral hemorrhage (ICH).

MATERIALS AND METHODS

We identified consecutive patients with non-traumatic ICH who presented directly to our Comprehensive Stroke Center over 2 years and collected data on demographics, clinical features, and stroke code activation. We used multivariable logistic regression to examine differences in stroke code activation based on patient demographics while adjusting for initial clinical features (NIH Stroke Scale, FAST [facial drooping, arm weakness, speech difficulties] vs. non-FAST symptoms, time from last-known-well [LKW], and systolic blood pressure [SBP]).

RESULTS

Among 265 patients, 68% (n=179) had a stroke code activation. Stroke codes occurred less frequently in women (62%) than men (72%) and in non-white (57%) vs. white patients (70%). Non-stroke code patients were less likely to have FAST symptoms (37% vs. 87%) and had lower initial SBP (mean±SD 159.3±34.2 vs. 176.0±31.9 mmHg) than stroke code patients. In our primary multivariable models, neither age nor race were associated with stroke code activation. However, women were significantly less likely to have stroke codes than men (OR 0.49 [95% CI 0.24-0.98]), as were non-FAST symptoms (OR 0.11 [95% CI 0.05-0.22]).

CONCLUSIONS

Our data suggest gender disparities in emergency stroke care that should prompt further investigations into potential systemic biases. Increased awareness of atypical stroke symptoms is also warranted.

Academic Productivity of United States Neurosurgeons Trained Abroad

BACKGROUND

Previous research in neurosurgery has examined academic productivity for U.S. medical graduates and residents. However, associations between scholarly output and international medical education, residency training, and fellowship training are scarcely documented.

METHODS

We identified 1671 U.S. academic neurosurgeons in 2020 using publicly available data along with their countries of medical school, residency, and fellowship training. Using Scopus, h-index, number of publications, and number of times publications were cited were compiled. Demographic, subspeciality, and academic productivity variables were compared between training locations using univariate analysis and multivariable linear regression.

RESULTS

Of the current neurosurgery faculty workforce, 16% completed at least 1 component of their training abroad. Canada was the most represented international country in the cohort. Academic productivity for neurosurgeons with international medical school and/or international residency did not significantly differ from that of neurosurgeons trained in the United States. Neurosurgeons with ≥1 U.S. fellowships or ≥1 international fellowships did not have higher academic productivity than neurosurgeons without a fellowship. However, dual fellowship training in both domestic and international programs was associated with higher mean h-index (β = 6.00, 95% confidence interval 1.01 to 10.98, P = 0.02), higher citations (β = 2092.0, 95% confidence interval 460.1 to 3724.0, P = 0.01), and a trend toward higher publications (β = 36.82, 95% confidence interval -0.21 to 73.85, P = 0.051).

CONCLUSIONS

Neurosurgeon scholarly output was not significantly affected by international training in medical school or residency. Dual fellowship training in both a domestic and an international program was associated with higher academic productivity.

Emergency medical services protocols for traumatic brain injury in the United States: A call for standardization

BACKGROUND

Traumatic brain injury (TBI) with acute elevation in intracranial pressure (ICP) is a neurologic emergency associated with significant morbidity and mortality. In addition to indicated trauma resuscitation, emergency department (ED) management includes empiric administration of hyperosmolar agents, rapid diagnostic imaging, anticoagulation reversal, and early neurosurgical consultation. Despite optimization of in-hospital care, patient outcomes may be worsened by variation in prehospital management. In this study, we evaluate geographic variation between emergency medical services (EMS) protocols for patients with suspected TBI.

METHODS

We performed a cross-sectional analysis of statewide EMS protocols in the United States in December 2020 and included all complete protocols published on government websites. Outcome measures were defined to include protocols or orders for the following interventions, given TBI: (1) hyperventilation and end-tidal capnography (EtCO2) goals, (2) administration of hyperosmolar agents, (3) tranexamic acid (TXA) administration for isolated head injury, (4) non-invasive management including head-of-bed elevation, and (5) hemodynamic goals.

RESULTS

We identified 32 statewide protocols including Washington, D.C., 4 of which did not include specific guidance for TBI. Of 28 states providing ventilatory guidance, 22/28 (78.6%) recommend hyperventilation, with 17/22 (77.3%) restricting hyperventilation to signs of acute herniation. The remaining 6 states prohibited hyperventilation. Regarding EtCO2 goals among states permitting hyperventilation, 17/22 (77.3%) targeted an EtCO2 of < 35 mmHg, while 5/22 (22.7%) provided no guide EtCO2 for hyperventilation. Rhode Island was the only state identified that included hypertonic saline (3%), and Delaware was the only state that allowed TXA in the setting of isolated TBI with GCS ≤ 12. Only 15/32 (46.9%) identified states recommend head-of-bed elevation. For blood pressure goals, 12/28 (42.9%) of states set minimum systolic blood pressure at 90 mmHg, while 10/28 (35.7%) set other SBP goals. The remaining 6/28 (21.4%) did not provide TBI-specific SBP goals.

CONCLUSIONS

There is wide variation among civilian prehospital protocols for traumatic brain injury. Prehospital care within the first "golden hour" may dramatically affect patient outcomes. Neurocritical care providers should be mindful of geographic variation in local protocols when designing and evaluating quality improvement interventions and should aim to standardize prehospital care protocols.

Common biomarkers of physiologic stress and associations with delirium in patients with intracerebral hemorrhage

PURPOSE

To examine associations between physiologic stress and delirium in the setting of a direct neurologic injury.

MATERIALS AND METHODS

We obtained initial neutrophil-to-lymphocyte ratio (NLR), glucose, and troponin in consecutive non-comatose patients with non-traumatic intracerebral hemorrhage (ICH) over 1 year, then used multivariable regression models to determine associations between each biomarker and incident delirium. Delirium diagnoses were established using DSM-5-based methods, with exploratory analyses further categorizing delirium as first occurring <24 h ("early-onset") or > 24 h after presentation ("later-onset").

RESULTS

Of 284 patients, delirium occurred in 55% (early-onset: 39% [n = 111]; later-onset: 16% [n = 46]). Patients with delirium had higher NLR (mean 9.0 ± 10.4 vs. 6.4 ± 5.5; p = 0.01), glucose (mean 146.5 ± 59.6 vs. 129.9 ± 41.4 mg/dL; p = 0.008), and a higher frequency of elevated troponin (>0.05 ng/mL; 21% vs. 10%, p = 0.02). In adjusted models, elevated NLR (highest quartile: OR 3.4 [95% CI 1.5-7.8]), glucose (>180 mg/dL: OR 3.1 [95% CI 1.1-8.2]), and troponin (OR 3.0 [95% CI 1.2-7.2]) were each associated with delirium, but only initial NLR was specifically associated with later-onset delirium and with delirium in non-mechanically ventilated patients.

CONCLUSIONS

Stress-related biomarkers corresponding to multiple organ systems are associated with ICH-related delirium. Early NLR elevation may also predict delayed-onset delirium, potentially implicating systemic inflammation as a contributory delirium mechanism.

Abstract P393: Risk Factors for Opioid Use in Patients With Intracerebral Hemorrhage

Background: Opioids are often used as analgesics in patients with subarachnoid hemorrhage, but their use in the setting of intracerebral hemorrhage (ICH) is not well described. We aimed to determine risk factors for opioid use in both the acute and post-discharge settings in patients with ICH.

Methods: We analyzed data from a single-center cohort of consecutive ICH patients admitted over two years. Demographics and ICH-related characteristics were prospectively collected as part of an institutional ICH registry, while pre-morbid, in-hospital, and post-discharge medications were retrospectively abstracted from medication administration records and physician documentation. After excluding patients who received end-of-life care, we used multivariable regression models adjusted for pre-morbid opioid use to determine demographic and ICH-related risk factors for in-hospital and post-discharge opioid use.

Results: Of 468 patients in our cohort, 15% (n=70) had pre-morbid opioid use, 53% (n=248) had in-hospital opioid use, and 12% (n=53) of survivors had opioids prescribed at discharge. The most commonly used in-hospital opioids were fentanyl (38% of patients), oxycodone (30%), morphine (26%), and hydromorphone (7%). Patients who received in-hospital opioids were significantly younger (mean 62.7 vs. 74.0 years, p<0.001) and had larger ICH volumes (mean 18.7 vs. 8.1 cc, p<0.001), with additional risk factors including infratentorial location (OR 4.0, 95% CI 2.0-8.0), presence of intraventricular hemorrhage (OR 4.3, 95% CI 2.5-7.5), and vascular, neoplastic, or other secondary ICH etiologies (OR 2.6, 95% CI 1.4-4.7) in multivariable models. However, only secondary ICH etiologies (OR 4.1, 95% CI 1.8-9.1) remained significant risk factors for opioid prescriptions at discharge in ICH survivors.

Conclusion: Inpatient opioid use in ICH patients is common, with risk factors that may be mechanistically connected to headache pathophysiology. However, the lower frequency of post-discharge opioid prescriptions may be reassuring given the prevalence of opioid dependence nationwide.

Abstract MP39: Modeling the Clinical Implications of Andexanet Alfa in Factor Xa Inhibitor-Associated Intracerebral Hemorrhage

Background: Andexanet alfa was recently approved as a reversal agent for the Factor Xa inhibitors (FXai) apixaban and rivaroxaban, but its impact on long-term outcomes in FXai-associated intracerebral hemorrhage (ICH) is unknown.

Methods: We performed a simulation study to determine the potential clinical implications of andexanet alfa across a range of possible hemostatic effects using data from a single-center cohort of ICH patients who did not receive the drug. We used this data to determine the baseline probability of insufficient hemostatic efficacy (IHE) across patients with and without FXai use via k-fold cross-validated multivariable regression models, which we aggregated into an IHE propensity score. We then determined the probability of unfavorable 3-month outcome (modified Rankin Scale 4-6) using a model comprised of established clinical predictors and IHE propensity. We applied model parameters from this derivation cohort to simulate a range of IHE reductions and corresponding outcomes, which we used to calculate absolute risk reduction (ARR) and projected number needed to treat (NNT) to prevent one unfavorable outcome.

Results: Training models using a real-world ICH cohort (n=604 total; 55 FXai patients) had good accuracy in predicting IHE (AUC 0.78) and unfavorable outcome (AUC 0.82). IHE was strongly associated with unfavorable outcome (OR 6.7, 95% CI 3.8-11.8) and occurred in 11.4% of FXai patients. Predicted ARR of unfavorable outcome was 5% (95% CI 3-8%) at one-third reduction of IHE and 8% (95% CI = 4-13%) at 50% IHE reduction, translating to a projected NNT of 20 (cumulative treatment cost $495,000) and 13 ($321,750), respectively.

Conclusion: Even optimistic simulated hemostatic effects suggest that the costs and potential benefits of andexanet alfa should be carefully considered, and placebo-controlled randomized trials are needed before its use can definitively be recommended.

Abstract P175: Dizziness-Related Symptoms are Associated With Delayed Diagnostic Imaging in Patients With Intracerebral Hemorrhage

Background: Acute dizziness can present diagnostic challenges for emergency department (ED) clinicians because of the potential for an underlying cerebrovascular cause. Although various strategies may aid in diagnosing cases caused by stroke, it is unclear whether dizziness due to intracerebral hemorrhage (ICH) is associated with delays in diagnostic imaging.

Methods: We performed a single center cohort study on consecutive ICH patients admitted over 2 years. We retrospectively abstracted initial reported symptoms and aggregated patients with dizziness, vertigo, lightheadedness, or nausea under the category of dizziness-related symptoms. After excluding patients with ED intubation due to potential procedural delays, we calculated time from initial ED arrival to first computed tomography (CT) scan. Using linear regression, we determined associations between dizziness-related symptoms and ED-to-CT time after adjusting for demographics and time from symptom onset, with additional analyses considering the presence of typical stroke symptoms and cerebellar ICH.

Results: Of 427 patients, 110 (26%) presented with dizziness-related symptoms and 36 (8%) had cerebellar ICH. In univariate analyses, patients with dizziness-related symptoms had longer ED-to-CT times than other patients (median [IQR] 51 [21-144] vs. 32 [14-92] min, p=0.007), as did those with cerebellar ICH (71 [27-182] min). In our primary adjusted model, dizziness-related symptoms were associated with longer ED-to-CT times (+26 min [95% CI 6-46]). This imaging delay was further compounded in a subgroup analysis of patients without typical stroke symptoms (+45 min [95% CI 7-84], and in a separate model considering patients with cerebellar ICH (+48 min [95% CI 17-80]).

Conclusions: Dizziness-related symptoms are associated with delayed diagnostic imaging in patients with ICH, which suggests the need for increased early awareness and urgency in these cases.

Abstract P455: Time to Blood Pressure Control and Association With Outcomes in Intracerebral Hemorrhage

Background: Urgent blood pressure (BP) control is a mainstay of acute intracerebral hemorrhage (ICH) treatment, but the relationship between time to BP control and clinical outcomes is unclear.

Methods: We performed a single-center observational cohort study on consecutive patients with ICH who were hypertensive on hospital arrival over a 2-year period. We defined time-to-BP-control as the time from initial hospital arrival to first BP recorded below our institutionally mandated goal (systolic BP [SBP] <160 mmHg). Using multivariable logistic regression models adjusted for established clinical predictors and time from last-known-well to hospital arrival, we determined associations between time-to-BP-control, hematoma expansion (HE), and unfavorable 3-month outcome (modified Rankin Scale 4-6). We performed additional subgroup analyses in patients with arrival SBP >200 mmHg, hypertensive ICH etiology, and anticoagulation-related ICH.

Results: Among 330 patients in our cohort, mean arrival SBP was 191±131 mmHg and mean time-to-BP-control was 2.3±1.5 hours. On univariate analysis, patients without HE had longer time-to-BP-control than those with HE (mean 2.5 vs. 2.1 hours, p=0.02). This was confirmed in multivariable models, where longer time-to-BP-control was associated with a lower likelihood of HE (OR 0.81 per hour, 95% CI 0.66-0.98), and was not associated with 3-month outcome (OR 0.99 per hour, 95% CI 0.81-1.21). Results were similar in subgroup analyses of patients with arrival SBP >200 mmHg and hypertensive ICH etiology. However, in those with anticoagulation-related ICH, longer time-to-BP-control was associated with a higher likelihood of unfavorable 3-month outcome (OR 2.02 per hour, 95% CI 1.13-3.61).

Conclusion: Earlier BP control may not improve outcomes in all ICH patients, though some subgroups, such as those with anticoagulation-related ICH, may derive greater benefit from earlier treatment.

Abstract P452: Impact of Socioeconomic Status in Intracerebral Hemorrhage

Background: Socioeconomic status (SES) has been associated with intracerebral hemorrhage (ICH) incidence, but its impact on ICH-related features and outcomes is unclear.

Methods: We performed a single-center cohort study on consecutive ICH patients admitted over 2 years. Demographics, ICH characteristics, and outcomes were prospectively collected, while SES-related data were retrospectively abstracted. We classified SES quartiles using census estimates of median household incomes corresponding to patients’ home ZIP codes, then categorized patients as “lower SES” if their ZIP code was in the lowest SES quartile, if they were uninsured, or had Medicaid as their source of insurance. We compared ICH characteristics between patients with lower vs. higher SES, then determined associations between lower SES and unfavorable 3-month outcome (modified Rankin Scale 4-6) using multivariable logistic regression.

Results: Of 665 patients, 31% (n=207) were categorized as lower SES. Patients with lower SES were significantly younger (mean [SD] 64.7 [16.1] vs. 73.1 [14.2] years, p<0.001), more often non-white (38% vs. 8%, p<0.001), and had a higher prevalence of multiple vascular risk factors. There were no significant differences in ICH volume or prevalence of infratentorial or intraventricular hemorrhage. However, patients with lower SES had a shorter time-to-presentation (median [IQR] 4.5 [1.3-15.2] vs. 7.4 [1.4-21.7]), hours from last known well, p=0.01), and had fewer ICH due to cerebral amyloid angiopathy (13% vs. 30%, p<0.001). Despite these differences, patients with lower SES did not have a significantly higher likelihood of unfavorable 3-month outcomes (OR 1.2 [95% CI 0.7-1.8]).

Conclusions: Differences in ICH features may be driven by pre-morbid healthcare disparities in lower SES patients. Although their younger age and shorter time to presentation may have mitigated the deleterious effects of comorbidities on long-term outcomes, these factors may also belie a greater loss of quality-adjusted life years from ICH-related disability.

Abstract TP339: Elevated Admission Troponin Predicts Unfavorable Outcomes After Intracerebral Hemorrhage in Patients With Atrial Fibrillation

Background: Intracerebral hemorrhage (ICH) often carries cardiac implications, and serum troponin has been suggested as a predictive biomarker for patients with ICH and other stroke subtypes. We aimed to determine whether previously described associations between troponin and worse outcomes in ICH patients varied based on the presence of atrial fibrillation (AF).

Methods: We performed a single-center cohort study using data from consecutive ICH patients admitted over 12 months. ICH characteristics and 3-month outcomes were prospectively collected, while admission troponin levels were retrospectively abstracted. We performed ordinal and binary logistic regression to determine associations between elevated troponins (>0.05 ng/mL) and 3-month outcomes (using the modified Rankin Scale [mRS]), with multivariable models adjusted for relevant demographics, ICH severity, and comorbidities including AF, anticoagulation use, coronary artery disease (CAD), and chronic kidney disease (CKD). An interaction variable combining elevated troponin and AF was also included in our models.

Results: Of 261 ICH patients with troponin measured on admission, 17% (n=44) had elevated troponins. Patients with elevated troponins were not significantly older than patients with normal troponin levels (mean age 74.8±13.6 vs. 70.4±15.4, p=0.08), but were more likely to have AF (36% vs. 21%, p=0.03), CAD (32% vs. 15%, p=0.007), and CKD (16% vs. 5%, p=0.006); ICH size, location, and other predictors were not significantly different between groups. In adjusted models, neither elevated troponin nor AF were independently associated with worse outcomes. However, the interaction between the two was significant (p=0.003), and the presence of elevated admission troponin in the context of AF was significantly associated with worse outcomes (ordinal: common OR 9.8 [95% CI 2.0-47.8]; binary (mRS 4-6): OR 14.4 [95% CI 1.9-106.4]).

Conclusions: Troponin may be a useful predictive biomarker in ICH patients with underlying AF, potentially signaling higher levels of cardiac and systemic stress in patients with lower cardiac reserve.

Abstract TMP92: Serum Markers of Physiologic Stress and Associations With Delirium in Patients With Intracerebral Hemorrhage

Background: Delirium occurs frequently in patients with intracerebral hemorrhage (ICH), though its pathogenesis may be multifactorial. Given the potential role of systemic stressors in delirium, we aimed to explore differences in commonly measured markers of physiologic stress between delirious and non-delirious ICH patients.

Methods: We performed a single-center cohort study using data from consecutive non-comatose ICH patients over 12 months. ICH and patient characteristics were prospectively collected, and the presence of delirium at any point during hospitalization was diagnosed based on DSM-5 criteria. We retrospectively abstracted admission laboratory values and selected three common markers of physiologic stress for comparison: neutrophil-lymphocyte ratio (NLR), troponin, and glucose. Using multivariable models adjusted for demographics, relevant comorbidities, and ICH severity, we determined associations between delirium and the following: NLR, using linear regression; elevated troponin (>0.05 ng/mL), using binary logistic regression; and elevated glucose (categorized as 130-180 or >180 mg/dL), using ordered logistic regression.

Results: Of 284 ICH patients in our cohort, 55% (n=157) had delirium. Patients with delirium were not significantly older than non-delirious patients (mean age 71.7±16.2 vs. 68.3±15.1, p=0.07), but had larger ICH volumes (mean 23.3±24.6 vs. 7.0±10.6 cc, p<0.001) and were more likely to have intraventricular hemorrhage (55% vs. 22%, p<0.001). Delirious patients also had higher admission NLR (mean 9.0±10.4 vs. 6.4±5.5, p=0.01) and glucose (mean 146.5±59.6 vs. 129.9±41.4 mg/dL, p=0.008), and were more likely to have elevated troponin (21% vs. 10%, p=0.02). In adjusted models, patients with delirium had higher admission NLR than patients who were never delirious (adjusted mean difference 2.6, 95% CI 0.3-4.9), and were more likely to have elevated admission troponin (OR 2.8, 95% CI 1.2-6.4) and glucose (OR 2.0, 95% CI 1.1-3.6).

Conclusions: Delirium after ICH is independently associated with elevated serum markers of physiologic stress, suggesting that systemic factors may be implicated in delirium pathogenesis.

Identification of stable reference genes for lipopolysaccharide-stimulated macrophage gene expression studies

Gene expression studies which utilize lipopolysaccharide (LPS)-stimulated macrophages to model immune signaling are widely used for elucidating the mechanisms of inflammation-related disease. When expression levels of target genes are quantified using Real-Time quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR), they are analyzed in comparison to reference genes, which should have stable expression. Judicious selection of reference genes is, therefore, critical to interpretation of qRT-PCR results. Ideal reference genes must be identified for each experimental system and demonstrated to remain constant under the experimental conditions. In this study, we evaluated the stability of eight common reference genes: Beta-2-microglobulin (B2M), Cyclophilin A/Peptidylprolyl isomerase A, glyceraldehyde-3-phosphatedehydrogenase (GAPDH), Hypoxanthine Phosphoribosyltransferase 1, Large Ribosomal Protein P0, TATA box binding protein, Ubiquitin C (UBC), and Ribosomal protein L13A. Expression stability of each gene was tested under different conditions of LPS stimulation and compared to untreated controls. Reference gene stabilities were analyzed using C_t value comparison, NormFinder, and geNorm. We found that UBC, closely followed by B2M, is the most stable gene, while the commonly used reference gene GAPDH is the least stable. Thus, for improved accuracy in evaluating gene expression levels, we propose the use of UBC to normalize PCR data from LPS-stimulated macrophages.