Effects of hours of sleep on ImPACT concussion testing: comparing baseline with postinjury scores.

OBJECTIVE: The influence of sleep on baseline and postconcussion neurocognitive performance prior to Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) is poorly understood. Since ImPACT is widely used in youth sport to assess neurocognitive performance before and after head injury, it is important to delineate factors that affect testing performance. While some have reported correlations between fewer hours of sleep and lower scores on baseline tests, others have not observed any such associations. Therefore, the authors sought to compare the relationship between sleep and neurocognitive performance on ImPACT at both baseline and postinjury. METHODS: The authors queried a database of 25,815 ImPACT tests taken from 2009 to 2019 by athletes aged 12-22 years. There were 11,564 baseline concussion tests and 7446 postinjury concussion ImPACT tests used in the analysis. Linear regression was used to model the effect of sleep on baseline and postconcussion ImPACT scores adjusting for sex, age, learning disability, attention-deficit/hyperactivity disorder, number of prior concussions, number of games missed, and strenuous exercise before testing. RESULTS: Mean composite scores expectedly were all significantly lower in the post-head injury group compared with the baseline group. In the multivariable analysis, at baseline, hours of sleep significantly affected symptom scores (ß = -1.050, 95% CI -1.187 to -0.9138; p < 0.0001). In the postinjury multivariable analysis, verbal memory (ß = 0.4595, 95% CI 0.2080-0.7110; p = 0.0003), visual memory (ß = 0.3111, 95% CI 0.04463-0.5777; p = 0.0221), impulse control (ß = -0.2321, 95% CI -0.3581 to -0.1062; p = 0.0003), and symptom scores (ß = -0.9168, 95% CI -1.259 to -0.5750; p < 0.0001) were all affected by hours of sleep. CONCLUSIONS: Hours of sleep did not alter neurocognitive metrics at baseline but did have an impact on post-head injury metrics. These findings suggest that individuals may be able to compensate for lack of sleep at baseline but not immediately after concussion. Concussions may reduce cognitive reserve or detract from the brain's resources, making sleep even more important for proper neurocognitive functioning postconcussion. Future work will analyze the effects of sleep on postconcussion test performance.

Identifying Predictors of Initial Surgical Failure during Minimally Invasive Endoscopic Intracerebral Hemorrhage Evacuation.

Background and Purpose: Intracerebral hemorrhage (ICH) is a common and severe disease with high rates of morbidity and mortality; however, minimally invasive surgical (MIS) hematoma evacuation represents a promising avenue for treatment. In February of 2019, the MISTIE III study found that stereotactic thrombolysis with catheter drainage did not benefit patients with supratentorial spontaneous ICH but that a clinical benefit may be present when no more than 15 mL of hematoma remains at the end of treatment. Intraoperative CT (iCT) imaging has the ability to assess whether or not this surgical goal has been met in real time, allowing for operations to add additional CT-informed 'evacuation periods' (EPs) to achieve the surgical goal. Here, we report on the frequency and predictors of initial surgical failure on at least one iCT requiring additional EPs in a large cohort of patients undergoing endoscopic minimally invasive ICH evacuation with the SCUBA technique. Methods: All patients who underwent minimally invasive endoscopic evacuation of supratentorial spontaneous ICH in a major health system between December 2015 and October 2018 were included in this study. Patient demographics, clinical and radiographic features, procedural details, and outcomes were analyzed retrospectively from a prospectively collected database. Procedures were characterized as initially successful when the first iCT demonstrated that surgical success had been achieved and initially unsuccessful when the surgical goal was not achieved, and additional EPs were performed. The surgical goal was prospectively identified in December of 2015 as leaving no more than 20% of the preoperative hematoma volume at the end of the procedure. Descriptive statistics and regression analyses were performed to identify predictors of initial failure and secondary rescue. Results: Patients (100) underwent minimally invasive endoscopic ICH evacuation in the angiography suite during the study time period. In 14 cases, the surgical goal was not met on the first iCT and multiple Eps were performed; in 10 cases the surgical goal was not met, and no additional EPs were performed. In 14 cases, the surgical goal was never achieved. When additional EPs were performed, a rescue rate of 71.4% (10/14) was seen, bringing the total percentage of cases meeting the surgical goal to 86% across the entire cohort. Cases in which the surgical goal was not achieved were significantly associated with older patients (68 years vs. 60 years; p = 0.0197) and higher rates of intraventricular hemorrhage (34.2% vs. 70.8%; p = 0.0021). Cases in which the surgical goal was rescued from initial failure had similar levels of IVH, suggesting that these additional complexities can be overcome with the use of additional iCT-informed EPs. Conclusions: Initial and ultimate surgical failure occurs in a small percentage of patients undergoing minimally invasive endoscopic ICH evacuation. The use of intraoperative imaging provides an opportunity to evaluate whether or not the surgical goal has been achieved, and to continue the procedure if the surgeon feels that more evacuation is achievable. Now that level-one evidence exists to target a surgical evacuation goal during minimally invasive ICH evacuation, intraoperative imaging, such as iCT, plays an important role in aiding the surgical team to achieve the surgical goal.

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.

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.

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 (ß = 0.06, p = 0.54) but does improve impulse control (ß = -0.45, p < 0.0001), verbal memory (ß = 0.23, p = 0.03), visualmotor (ß = 0.77, p < 0.0001), and reaction time (ß = -0.008, p < 0.0001) scores.  However, age did not have an effect on visual memory scores (ß = -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.

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.

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.

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) (ß = 2.67, 95% CI: 1.47-3.87, p < .0001) and worse Impulse Control scores (ß = 0.93, 95% CI: 0.33-1.53, p = .002). In multivariate analysis, this association was the same for symptom score (ß = 2.48, 95% CI: 1.22-3.74, p < .0001), but Impulse Control was not significantly different after multiple comparison adjustment (ß = 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.

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.

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.

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.

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 (ß = -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 (ß = 1.22, 95% CI 0.27-2.18, p = 0.012), sleep (ß = 0.63, 95% CI 0.17-1.08, p = 0.007), and neuropsychiatric (ß = 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 Toward 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 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 toward VR were assessed. Neurosurgery residents performed external ventricular drain 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 = 0.02). Student attitudes regarding VR utility improved significantly posttrial. 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 = 0.007) and trial 2 (7.45 [6.43-8.3] vs. 19.5 [10.9-27.6], P = 0.002). By trial 3 there was no significant difference (10.1 [8.63-10.95 vs. 9.7 [5.8-15.3], P = 0.62). 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.

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

BACKGROUND: Teleproctoring is an emerging method of bedside clinical teaching; however, its feasibility has been limited by the available technologies. The use of novel tools that incorporate 3-dimensional environmental information and feedback might offer better bedside teaching options for neurosurgical procedures, including external ventricular drain placement. METHODS: A platform with a camera-projector system was used to proctor medical students on placing external ventricular drains on an anatomic model as a proof-of-concept study. Three-dimensional depth information of the model and surrounding environment was captured by the camera system and provided to the proctor who could provide projected annotations in a geometrically compensated manner onto the head model in real time. The medical students were randomized to identify Kocher's point on the anatomic model with or without the navigation system. The time required to identify Kocher's point and the accuracy were measured as a proxy for determining the effectiveness of the navigation proctoring system. RESULTS: Twenty students were enrolled in the present study. Those in the experimental group identified Kocher's point an average of 130 seconds faster than did the control group (P < 0.001). The mean diagonal distance from Kocher's point was 8.0 ± 4.29 mm for the experimental group compared with 23.6 ± 21.98 mm for the control group (P = 0.053). Of the 10 students randomized to the camera-projector system arm, 70% were accurate to within 1 cm of Kocher's point compared with 40% of the control arm (P > 0.05). CONCLUSIONS: Camera-projector systems for bedside procedure proctoring and navigation are a viable and valuable technology. We demonstrated its viability for external ventricular drain placement as a proof-of-concept. However, the versatility of this technology indicates that that it could be useful for a variety of even more complex neurosurgical procedures.

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.

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.

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.

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.

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.