AMPK induces regulatory innate lymphoid cells after traumatic brain injury.

The CNS is regarded as an immunoprivileged organ, evading routine immune surveillance; however, the coordinated development of immune responses profoundly influences outcomes after brain injury. Innate lymphoid cells (ILCs) are cytokine-producing cells that are critical for the initiation, modulation, and resolution of inflammation, but the functional relevance and mechanistic regulation of ILCs are unexplored after acute brain injury. We demonstrate increased proliferation of all ILC subtypes within the meninges for up to 1 year after experimental traumatic brain injury (TBI) while ILCs were present within resected dura and elevated within cerebrospinal fluid (CSF) of moderate-to-severe TBI patients. In line with energetic derangements after TBI, inhibition of the metabolic regulator, AMPK, increased meningeal ILC expansion, whereas AMPK activation suppressed proinflammatory ILC1/ILC3 and increased the frequency of IL-10-expressing ILC2 after TBI. Moreover, intracisternal administration of IL-33 activated AMPK, expanded ILC2, and suppressed ILC1 and ILC3 within the meninges of WT and Rag1-/- mice, but not Rag1-/- IL2rg-/- mice. Taken together, we identify AMPK as a brake on the expansion of proinflammatory, CNS-resident ILCs after brain injury. These findings establish a mechanistic framework whereby immunometabolic modulation of ILCs may direct the specificity, timing, and magnitude of cerebral immunity.

Dynamic Cervical Cord Compression Post-laminectomy Visualized by Flexion-extension Magnetic Resonance Imaging: Case Report.

Flexion-extension magnetic resonance imaging (MRI) in the cervical spine is not universally used in cervical spine surgery. However, flexion-extension MRIs can identify previously undetected spinal stenosis, improve surgical decision-making, and maybe a better tool to evaluate postoperative outcomes. One uncommon complication after laminectomy, to treat cervical spinal stenosis, is muscle weakness due to subsequent dynamic cord compression by posterior paraspinal musculature. We present a case of a 41-year-old male who underwent posterior cervical decompression and developed subsequent neurological deficits and muscle weakness. MRI with neutral cervical positioning did not show spinal stenosis necessitating surgical intervention. However, given the patient's increasing tetraparesis, flexion-extension MRI was performed and it revealed significant spinal stenosis in both flexion and extension positions due to spondylosis and compression from paraspinal muscles. This case demonstrates the utility of flexion-extension MRI in identifying pathologies such as cord compression by paraspinal muscles. Exclusive use of a neutral-position MRI scan may not be sufficient to provide proper diagnoses for cervical spine pathologies. Flexion-extension MRI should be considered when the degree of neurological symptoms outweighs minimal or absent pathology seen on neutral-position sagittal MRI.

Workforce Analysis of Spine Surgeons Involved with Neurological and Orthopedic Surgery Residency Training.

OBJECTIVE: Spinal surgery is taught and practiced within 2 different surgical disciplines: neurological surgery and orthopedic surgery. We have provided a unified analysis of spine-focused faculty at U.S. residency programs. METHODS: A total of 278 Accreditation Council for Graduate Medical Education training programs were assessed to identify 923 full-time faculty members with a spinal surgery designation, defined by spine fellowship training or surgeon case volume >75% spine surgeries. Faculty were assessed with respect to parent discipline, years of fellowship training, academic rank, gender, and academic productivity (h-index). RESULTS: The spine-teaching workforce contains 55% orthopedic surgeons and 45% neurosurgeons with wide gender asymmetry overall and at all faculty ranks. Of the female spine surgeons, those with neurosurgical training (64.44%) nearly doubled the number with orthopedic training (35.56%). Academic productivity increased with academic rank similarly for both genders and subspecialties. Orthopedic spine surgeons had a greater mean fellowship number compared with the neurological spine surgeons. Fellowship time of completion (intraresidency/infolded vs. postresidency) did not significantly affect the h-indexes. Addition of fellowship conferred academic productivity benefit for orthopedic surgeons only. CONCLUSIONS: Neurological and orthopedic spine surgery showed similar patterns for the spread of faculty across academic ranks and trends in academic productivity. Marked gender disparity was seen in both neurosurgical and orthopedic surgery, with fewer female spine surgeons seen at every academic rank. Orthopedic spine surgeons had a greater mean fellowship number than did their neurosurgical counterparts, and a lack of fellowship correlated with lower academic productivity in orthopedic, but not neurological, spine surgery.

Academic Productivity of Spine Surgeons at United States Neurological Surgery and Orthopedic Surgery Training Programs.

OBJECTIVE: Spinal surgery is taught and practiced within 2 different surgical disciplines, neurological surgery and orthopedic surgery. We have provided a unified analysis of academic productivity measured using the h-index attributable to spine-focused faculty at U.S. residency programs. METHODS: A total of 278 Accreditation Council for Graduate Medical Education training programs were assessed to identify 923 full-time faculty members with a spinal surgery designation, as defined by spine fellowship training or case volume >75% in spine surgery. The faculty were assessed with respect to academic rank, duration of practice in years, and academic productivity (h-index). RESULTS: The comparison showed a significantly greater mean h-index for neurological spine surgeons. The mean h-index for both disciplines increased significantly as faculty rank increased. Within the academic ranks of assistant and associate professor, neurological spine surgeons had significantly greater mean h-indexes. Neurological spine surgeons had a significantly lower practice duration. At all ranks except for assistant professor, the mean practice duration was not significantly different statistically between the neurological spine and orthopedic spine surgeons. A positive correlation between the h-index and practice duration was found for both spine surgical disciplines. The proportional odds models for neurological and orthopedic spine surgeons were moderately successful at predicting faculty rank according to the h-index. CONCLUSIONS: We present a unified view of academic productivity as measured by the h-index among neurosurgical and orthopedic surgery spine faculty, with some noticeable differences. These results can be used for benchmark purposes to assess the relative productivity of its faculty and could be of interest to those pursuing academic opportunities in spine surgery.

Spontaneous Arrest of Sporadic Spinal Hemangioblastoma Growth after Postoperative Nodular Recurrence: Case Report.

Hemangioblastomas are rare, slow-growing, highly vascularized tumors of the central nervous system which often occur in the spinal cord. When presenting as sporadic, isolated tumors without Von-Hippel Lindau disease, they are curable through surgery with a low rate of recurrence. Tumor recurrence in these cases is usually associated with prior subtotal resection. However, to the best of our knowledge, cases of recurrent, sporadic spinal hemangioblastoma have not been reported to spontaneously arrest without intervention or symptoms. We report a patient who underwent an initial complete resection of a cervical spinal hemangioblastoma, a subtotal resection of tumor recurrence four and a half years later, and nine years of neurologic and radiographic stability with no additional interventions.

Evaluation of Concussion Incidence and Modulating Factors in the 2013-2017 Australian Football League.

Introduction The increasing awareness and popularization of concussions in the research realm over the last few years have begun to shed more light on the detrimental effects associated with repetitive head trauma. While the majority of the current literature focuses on the National Football League (NFL) and National Hockey League (NHL), several other high-impact sports have been implementing concussion management protocols to protect their players. The Australian Football League (AFL) is a prime example of a major contact sport that has undertaken recent changes to its concussion assessment and management modalities. We recognize the benefit of reporting potential changes in concussion rates over the 2013-2017 AFL seasons. We were interested in some of the factors not yet evaluated before, which may contribute to the overall concussion incidence such as "style-of-play" factors" (home/away, win/loss, points scored, time of season). We hope the results of this analysis shed light on the mechanisms by which concussion rates can be mitigated across major contact sports. Methods Data were obtained from the weekly injury list published by the AFL, a publicly available website. Details of players listed with concussions were collected from regular season games (890 games total) of 18 AFL teams from 2013 to 2017. Weekly injury lists were retrospectively compared using THE AGE, a publicly available newspaper published and owned by Fairfax Media. Data were analyzed utilizing GraphPad Prism 6 (GraphPad Software Inc., CA, US). In addition to descriptive statistics, Fisher's exact tests, Welch's two-tailed t-tests, and correlation tests were used. Alpha level < 0.05 was considered significant for all tests. Results The dataset comprised 236 total concussions between the 2013 and 2017 AFL seasons. We noted a significant increase in the concussion rate (p = 0.0010) between the 2013 and 2017 seasons. This result was complemented by a significant increase in average games missed between the 2014 and 2015 seasons (p = 0.0002); however, this trend was not significant when evaluating the 2013 and 2017 seasons directly (p = 0.0951). Further analysis into the "style of play" factors on concussion incidence, such as average points scored, win/loss, home/away, and time of season, produced non-significant results. Conclusion Our study identified a significant increasing trend in concussion rate and average games missed that correlate to the data analysis in other high-impact sports such as the NFL and NHL. However, further research is necessary to determine if these findings indicate the improvement in concussion management and player safety measures beginning to develop in high-impact sports. We also noted that certain "style of play" factors (points scored, win/loss, home/away, and time of season) have no significant implication on concussion rate during the 2013-2017 AFL seasons. While we consider our data source to be reliable in the reporting of concussions from the AFL, the ideal data set would comprise a medical diagnosis from the team of doctors. It may be possible that our data set is underreporting the total amount of concussions between the 2013 and 2017 AFL seasons. Return-to-play times were not ascertained directly from the team doctor for the clearance date. It may be possible that this data collection modality led to missed cases of head injury or return to play times, which could impact the reliability of our dataset.

Effects of Game Characteristics and Player Positions on Concussion Incidence and Severity in Professional Football.

BACKGROUND: Increasing efforts have been made to reduce the incidence and severity of concussion in high-contact sports. Despite these efforts, a relative lack of knowledge is available regarding modulating factors affecting concussion injury. PURPOSE: To analyze the potential influence of game characteristics and outcomes on concussion incidence and severity in professional football. STUDY DESIGN: Descriptive epidemiology study. METHODS: PBS Frontline Concussion Watch was used to collect concussion injury data from regular-season games of 32 National Football League (NFL) teams from 2012 to 2015. Game characteristic variables such as rushing and passing attempts, turnovers, and margin of victory were collected from ESPN. Analysis included descriptive statistics, analysis of variance, t tests, and correlation tests. RESULTS: Away teams demonstrated a significantly greater concussion incidence per game than home teams. Losing teams had a significantly greater concussion incidence per game than winning teams. Being both the away team and the losing team appeared to have an additive effect. The home-versus-away and win-versus-loss effects were significant for offensive but not defensive positions. Within individual positions, significantly greater concussion incidence was associated with tight ends, running backs, wide receivers, and cornerbacks. When running versus passing positions were compared, passing positions (wide receiver, tight end, cornerback, safety) had significantly greater concussion incidence. A total of 626 games were missed as a result of reported concussions. Away teams had significantly more games missed due to concussion when they lost. Play time did not significantly differ before or after concussion injury. Other game characteristic variables did not significantly affect concussion frequency or intensity. CONCLUSION: Position, game location, and game outcome affect concussion incidence for professional football players. In a subset of analyses, the number of games missed aligned with concussion incidence, but this appeared to be an imperfect measure. These findings highlight new factors that may modulate concussion incidence and merit further study on how they may influence concussion evaluation.

Modifying Factors for Concussion Incidence and Severity in the 2013-2017 National Hockey League Seasons.

Introduction In the past few years, there has been a rising interest in both the prevalence and the short- and long-term consequences of concussions. While the main focus of concussion-based research revolves around the National Football League (NFL), attention is now shifting to other high contact leagues like the National Hockey League (NHL), where there is constant player-to-player contact as well as collisions with the perimeter boards. While the body of evidence surrounding injury and concussion rates in the NHL has substantially grown in size over the previous few years, there is still a void pertaining to the in-game effects that could modulate concussion incidence. Our study takes a novel approach to evaluate several "style of play" factors such as home/away perspective, win/loss outcome, points scored, real time length of game, time of season, and player position in modulating concussion rates. Methods Data on concussion incidence for the 2013-2017 National Hockey League seasons was collected utilizing FOX Sports injury tracker. Only injuries specifically diagnosed as concussions during regular and postseason games were utilized in our data set. A Google search on the reported injury was performed in order to correlate the concussion to the correct game in which the player sustained it. NHL season schedules were acquired through the online source "Hockey Reference." There were a total of 5281 games when considering the regular and postseason games between the 2013-2017 seasons. Concussions sustained during team practices and preseason contests were not accounted for in our data set to control for inconsistent reporting. Our data set does not account for the current 2017-2018 NHL expansion with the addition of a Las Vegas team to the league. Results Statistical analysis of several "Style of Play" factors such as home/away perspective, win/loss outcome, points scored, real time length of game and time of season produced non-significant results pertaining to modulating concussion rate during the 2013-2017 NHL seasons. When evaluating on-ice position we noted offensive players combined to have the highest rate of concussion. Forwards (left wing (LW), right wing (RW)) demonstrated similar concussion rates, while goalies encountered the lowest concussion rate. Conclusion The results of our analysis demonstrated non-significance for home/away effects, win/loss results, average points scored, real time length of game, and time of season on influencing concussion rates. We noted offensive players combined to have the highest rate of concussions, while goalies encountered the least. The key limitation in our data set is the lack of reliable and publicly available data surrounding concussion incidence in the National Hockey League. Due to this drawback, our data set should be considered as an under-reported representation of the total amount of concussions spanning the 2013-2017 seasons.

Does the Environment Influence the Frequency of Concussion Incidence in Professional Football?

Background Sports-related concussion is a major cause of mild traumatic brain injury (mTBI). It is possible that environmental factors, such as temperature, humidity, and stadium's altitude, may influence the overall incidence of concussions during a game. Purpose To examine the impact of environmental factors, such as temperature, humidity, barometric pressure, and dew point, on concussion incidence. Methods Public Broadcasting Service (PBS) FRONTLINE Concussion Watch was used to collect injury data on 32 NFL teams during regular season games from 2012 to 2015. Weather data points were collected from Weather Underground. Concussion incidence per game, the probability of a concussion during a game, and a difference in mean game-day temperature, humidity, dew point, and barometric pressure between concussion and concussion-free games were calculated. Our analysis included t-tests, analysis of variance (ANOVA), multivariate correlation tests, and logistic and Poisson regression.  Results Overall, 564 concussions were reported. There were 411 games with concussions and 549 games without concussions. We observed a significant decrease in concussion incidence with increasing temperature, both when the temperature was divided into 20oF increments or into quartiles (p = 0.005 and p = 0.002, respectively). We identified a statistically significant lower mean-game day temperature in concussion games compared to concussion-free games (p < 0.0006). We also observed a significant decrease in the incidence of concussion per game with increasing dew point. There was no significant difference in concussion incidence in barometric pressure and humidity. The logistic regression model predicted a decrease in the probability of a concussion in games with higher temperatures and dew points. Conclusions National Football League (NFL) players experienced an increased risk of concussion during football games played in colder temperatures and at lower dew points. Further research on environmental effects on concussions may aid in improving player safety in football leagues.

Pediatric hydrocephalus: systematic literature review and evidence-based guidelines. Part 10: Change in ventricle size as a measurement of effective treatment of hydrocephalus.

OBJECT: The objective of this systematic review is to answer the following question: Does ventricle size after treatment have a predictive value in determining the effectiveness of surgical intervention in pediatric hydrocephalus? METHODS: The US National Library of Medicine PubMed/MEDLINE database and the Cochrane Database of Systematic Reviews were searched using MeSH headings and key words relevant to change in ventricle size after surgical intervention for hydrocephalus in children. An evidentiary table was assembled summarizing the studies and the quality of evidence (Classes I-III). RESULTS: Six articles satisfied inclusion criteria for the evidentiary tables for this part of the guidelines. All were Class III retrospective studies. CONCLUSIONS/RECOMMENDATIon: There is insufficient evidence to recommend a specific change in ventricle size as a measurement of the effective treatment of hydrocephalus and as a measurement of the timing and effectiveness of treatments including ventriculoperitoneal shunts and third ventriculostomies. STRENGTH OF RECOMMENDATION: Level III, unclear clinical certainty.

Novel surgical treatment of a transverse-sigmoid sinus aneurysm presenting as pulsatile tinnitus: technical case report.

OBJECTIVE: Pulsatile tinnitus is a relatively common, potentially incapacitating condition that is often vascular in origin. We present a case of disabling pulsatile tinnitus caused by a transverse-sigmoid sinus aneurysm that was surgically treated with self-tying U-clips (Medtronic, Inc., Memphis, TN). We also review the literature and discuss other described interventions. CLINICAL PRESENTATION: A 48-year-old woman presented with a 5-year history of progressive pulsatile tinnitus involving the right ear. Her physical examination was consistent with a lesion that was venous in origin. Angiography demonstrated a wide-necked venous aneurysm of the transverse-sigmoid sinus that had eroded the mastoid bone. INTERVENTION: The patient underwent a retromastoid suboccipital craniectomy to expose the aneurysm and surrounding anatomy. The aneurysm dome was tamponaded and the aneurysm neck was coagulated until the dome had shrunk to a small remnant. The linear defect in the transverse sigmoid junction was then reconstructed with a series of U-clips and covered with Gelfoam hemostatic sponge (Pfizer, Inc., New York, NY). The patient awakened without neurological deficit and with immediate resolution of her tinnitus. A postoperative angiogram demonstrated obliteration of the aneurysm, with minimal stenosis in the region of the repair and good flow through the dominant right transverse-sigmoid junction. CONCLUSION: This technical case report describes a novel definitive surgical treatment of venous sinus aneurysms. This technique does not necessitate long-term anticoagulation, has a low likelihood of reintervention, and provides immediate resolution of pulsatile tinnitus.