Objective The objective was to determine the impact of the COVID-19 pandemic on operative case volume in 8 US neurosurgical residency training programs in early 2020 and to survey these programs regarding training activities during this period. Methods A retrospective review was conducted of monthly operative case volumes and types for 8 residency programs for 2019 and January-April 2020. Cases were grouped as elective cranial, elective spine, and non-elective emergent cases. Programs were surveyed regarding residents’ perceptions of the impact of COVID-19 on surgical training, didactics, and research participation. Data was analyzed for individual programs and pooled across programs. Results Across programs, the 2019 monthly case average was 211 (SD ± 82); 2020 average case volumes for January, February, March, and April were 228±93, 214±84, 180±73, and 107±45, respectively. Compared with 2019, March and April 2020 average cases declined 15% (p=0.003) and 49% (p=0.002), respectively. COVID-19 affected surgical case volume for all programs; 75% reported didactics negatively affected, and 90% reported COVID-19 resulted in increased research time. Several neurosurgery residents have required COVID-19 testing, however, to our knowledge, only one resident from the participating programs tested positive. Conclusions This study documents a significant reduction in operative volume in 8 neurosurgery residency training programs in early 2020. During this time, neurosurgery residents engaged in online didactics and research-related activities, reporting increased research productivity. Residency programs should collect data to determine the educational impact of the pandemic on resident operative case volumes, identify deficiencies, and develop plans to mitigate any effects.

While intravenous administration of tissue plasminogen activator (tPA) remains the only FDA-approved treatment modality for acute ischemic stroke, many patients do not meet the criteria for intravenous tPA and are offered intra-arterial therapy. Rapid advances in devices and approaches have marked the evolution of thrombectomy over the past decade from rudimentary mechanical disruption, followed by intra-arterial thrombolytic infusions to increasingly effective thrombectomy devices. We review the critical advancements in thrombectomy technique that have evolved and the key anatomic and technical challenges they address, from first-generation Merci retrieval systems to second-generation Penumbra aspiration systems and third-generation stent retrievers, as well as nuances of their uses to maximize their effectiveness. We also highlight more recent advances that offer patients hope for more expedient vessel recanalization.

Kellogg R, Mackie K, Straiker A. Cannabinoid CB1 receptordependent long-term depression in autaptic excitatory neurons. J Neurophysiol 102: 1160 -1171. First published June 3, 2009 doi:10.1152/jn.00266.2009. Long-term depression (LTD) of synaptic signaling-lasting from tens of minutes to hours or longer-is a widespread form of synaptic plasticity in the brain. Neurons express diverse forms of LTD, including autaptic LTD (autLTD) observed in cultured hippocampal neurons, the mechanism of which remains unknown. We have recently reported that autaptic neurons express both endocannabinoid-mediated depolarization-induced suppression of excitation (DSE) and metabotropic suppression of excitation (MSE). We now report that activating cannabinoid CB 1 receptors is necessary for the induction of autLTD. Most surprisingly, CB 1 does not induce autLTD via the G i/o proteins typically activated by this receptor nor with G s . Rather, the requirements of presynaptic phospholipase C and filled calcium stores suggest G q . In autLTD, a 3-to 4-min activation of the receptor by the endocannabinoid 2-arachidonoyl glycerol leads to prolonged inhibition while leaving short-term inhibition (e.g., DSE) intact. autLTD requires activation of both metaboand ionotropic glutamate receptors. autLTD also requires MEK/ERK activation. Under certain conditions, one or more DSE stimuli will elicit autLTD. It is becoming evident that cannabinoids mediate multiple forms of plasticity at a single synapse, stretching temporally from tens of seconds (DSE/MSE) to tens of minutes (autLTD) to hours (CB 1 desensitization). Our findings imply a remarkable flexibility for the cannabinoid signaling system whereby discrete mechanisms of CB 1 activation within a single neuron yield temporally and mechanistically distinct forms of plasticity.

ET in the elderly did not show a similar benefit to younger patients when compared with medical management. These findings emphasize the need for more optimal selection criteria for the elderly population to improve the risk to benefit ratio of ET.