Active Teaching Techniques Using Virtual Didactics: Novel Experience From a National Neurosurgery Resident Course.

OBJECTIVE: To investigate the attitudes of neurosurgery residents regarding active teaching techniques and virtual didactics based on a national neurosurgery resident sample. We also evaluated the relative cost and time commitment required for faculty participation in virtual versus in-person resident courses. DESIGN: The Society of Neurological Surgeons (SNS) national junior resident courses (JRCs) were reformatted for active teaching in a virtual setting in 2020 due to the COVID-19 pandemic. We analyzed course evaluations from the virtual 2020 courses in comparison to the 2019 in-person SNS JRCs. We also compared course budgets and agendas from these courses to identify comparative costs and the time commitment for faculty participation using these 2 course models. SETTING: Survey of nationwide participants in virtual junior resident courses. PARTICIPANTS: A total of 122 residents from 80 ACGME neurosurgery residency training programs attended the 2020 virtual JRC. RESULTS: The survey response rate of attendees was 36%. In-class engagement was thought to be good to great by 73% to 80% of the virtual learners. In-class activities and active learning techniques also were evaluated positively by 61% to 82% of respondents. Expenses were significantly lower for the virtual course, at $118 per course participant, than for the in-person course ($2722 per participant). There also was a 97.3% reduction of faculty hours and a 97.6% reduction of faculty cost for the virtual JRC compared to the in-person course. CONCLUSIONS: Neurosurgeon residents embraced the active teaching techniques used to teach portions of the prepandemic JRCs in a virtual format. Other aspects of the course curriculum could not be replicated virtually. Virtual courses were dramatically less expensive to produce, used fewer faculty teachers and required less time per faculty member. The data from this study may inform the choice of active teaching techniques for other neurosurgery residency and continuing medical education courses to optimize learner engagement and participant satisfaction in the virtual setting. We recommend that the curriculum of in-person courses emphasize hands-on, experiential learning and professional enculturation that cannot be recreated in the virtual space. Curricular elements suitable to virtual learning should take advantage of lower costs, reduced faculty time requirements, and scalability. They should also utilize active teaching techniques to improve learner engagement.

Re-evaluating Biopsy for Recurrent Glioblastoma: A Position Statement by the Christopher Davidson Forum Investigators.

Patients with glioblastoma (GBM) need bold new approaches to their treatment, yet progress has been hindered by a relative inability to dynamically track treatment response, mechanisms of resistance, evolution of targetable mutations, and changes in mutational burden. We are writing on behalf of a multidisciplinary group of academic neuro-oncology professionals who met at the collaborative Christopher Davidson Forum at Washington University in St Louis in the fall of 2019. We propose a dramatic but necessary change to the routine management of patients with GBM to advance the field: to routinely biopsy recurrent GBM at the time of presumed recurrence. Data derived from these samples will identify true recurrence vs treatment effect, avoid treatments with little chance of success, enable clinical trial access, and aid in the scientific advancement of our understanding of GBM.

Tau elevations in the brain extracellular space correlate with reduced amyloid-ß levels and predict adverse clinical outcomes after severe traumatic brain injury.

Axonal injury is believed to be a major determinant of adverse outcomes following traumatic brain injury. However, it has been difficult to assess acutely the severity of axonal injury in human traumatic brain injury patients. We hypothesized that microdialysis-based measurements of the brain extracellular fluid levels of tau and neurofilament light chain, two low molecular weight axonal proteins, could be helpful in this regard. To test this hypothesis, 100 kDa cut-off microdialysis catheters were placed in 16 patients with severe traumatic brain injury at two neurological/neurosurgical intensive care units. Tau levels in the microdialysis samples were highest early and fell over time in all patients. Initial tau levels were >3-fold higher in patients with microdialysis catheters placed in pericontusional regions than in patients in whom catheters were placed in normal-appearing right frontal lobe tissue (P = 0.005). Tau levels and neurofilament light-chain levels were positively correlated (r = 0.6, P = 0.013). Neurofilament light-chain levels were also higher in patients with pericontusional catheters (P = 0.04). Interestingly, initial tau levels were inversely correlated with initial amyloid-ß levels measured in the same samples (r = -0.87, P = 0.000023). This could be due to reduced synaptic activity in areas with substantial axonal injury, as amyloid-ß release is closely coupled with synaptic activity. Importantly, high initial tau levels correlated with worse clinical outcomes, as assessed using the Glasgow Outcome Scale 6 months after injury (r = -0.6, P = 0.018). Taken together, our data add support for the hypothesis that axonal injury may be related to long-term impairments following traumatic brain injury. Microdialysis-based measurement of tau levels in the brain extracellular space may be a useful way to assess the severity of axonal injury acutely in the intensive care unit. Further studies with larger numbers of patients will be required to assess the reproducibility of these findings and to determine whether this approach provides added value when combined with clinical and radiological information.

ACR Appropriateness Criteria® on cerebrovascular disease.

Stroke is the sudden onset of focal neurologic symptoms due to ischemia or hemorrhage in the brain. Current FDA-approved clinical treatment of acute ischemic stroke involves the use of the intravenous thrombolytic agent recombinant tissue plasminogen activator given <3 hours after symptom onset, following the exclusion of intracerebral hemorrhage by a noncontrast CT scan. Advanced MRI, CT, and other techniques may confirm the stroke diagnosis and subtype, demonstrate lesion location, identify vascular occlusion, and guide other management decisions but, within the first 3 hours after ictus, should not delay or be used to withhold recombinant tissue plasminogen activator therapy after the exclusion of acute hemorrhage on noncontrast CT scans. MR diffusion-weighted imaging is highly sensitive and specific for acute cerebral ischemia and, when combined with perfusion-weighted imaging, may be used to identify potentially salvageable ischemic tissue, especially in the period >3 hours after symptom onset. Advanced CT perfusion methods improve sensitivity to acute ischemia and are increasingly used with CT angiography to evaluate acute stroke as a supplement to noncontrast CT. The ACR Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Characterizing learning deficits and hippocampal neuron loss following transient global cerebral ischemia in rats.

The 2-vessel-occlusion + hypotension (2VO + H) model of transient global cerebral ischemia results in neurodegeneration within the CA1 field of the hippocampus, but previous research has failed to demonstrate robust or reliable learning/memory deficits in rats subjected to this treatment. In the present study, sensitive behavioral protocols were developed in an effort to characterize the cognitive impairments following 2VO + H more precisely. Adult rats were exposed to 10 min of bilateral carotid occlusion with simultaneous hypotension. Following recovery, 2VO + H and control rats were subjected to a series of behavioral tests (locomotor activity, sensorimotor battery, water maze [cued, place, learning set], object recognition, and radial arm maze) over an extended recovery period followed by an assessment of neuronal loss in the dorsal hippocampus. The 2VO + H treatment was associated with long-lasting spatial learning deficits in the absence of other behavioral impairments and with neurodegeneration in dorsal hippocampal CA1. Water maze protocols that placed higher memory demands upon the rats (relatively "hard" vs. "easy") were more sensitive for detecting ischemia-induced deficits. We have shown that the use of appropriate behavioral tests (e.g., a relatively difficult place learning task) allowed for the observation of robust spatial learning deficits in a model previously shown to induce relatively subtle behavioral effects. Thus, the 2VO + H model induces both hippocampal neuronal loss and long-term learning deficits in rats, providing a potentially useful model for evaluating therapeutic efficacy.