T12-L3 Nerve Transfer-Induced Locomotor Recovery in Rats with Thoracolumbar Contusion: Essential Roles of Sensory Input Rerouting and Central Neuroplasticity.

Locomotor recovery after spinal cord injury (SCI) remains an unmet challenge. Nerve transfer (NT), the connection of a functional/expendable peripheral nerve to a paralyzed nerve root, has long been clinically applied, aiming to restore motor control. However, outcomes have been inconsistent, suggesting that NT-induced neurological reinstatement may require activation of mechanisms beyond motor axon reinnervation (our hypothesis). We previously reported that to enhance rat locomotion following T13-L1 hemisection, T12-L3 NT must be performed within timeframes optimal for sensory nerve regrowth. Here, T12-L3 NT was performed for adult female rats with subacute (7-9 days) or chronic (8 weeks) mild (SCImi: 10 g × 12.5 mm) or moderate (SCImo: 10 g × 25 mm) T13-L1 thoracolumbar contusion. For chronic injuries, T11-12 implantation of adult hMSCs (1-week before NT), post-NT intramuscular delivery of FGF2, and environmentally enriched/enlarged (EEE) housing were provided. NT, not control procedures, qualitatively improved locomotion in both SCImi groups and animals with subacute SCImo. However, delayed NT did not produce neurological scale upgrading conversion for SCImo rats. Ablation of the T12 ventral/motor or dorsal/sensory root determined that the T12-L3 sensory input played a key role in hindlimb reanimation. Pharmacological, electrophysiological, and trans-synaptic tracing assays revealed that NT strengthened integrity of the propriospinal network, serotonergic neuromodulation, and the neuromuscular junction. Besides key outcomes of thoracolumbar contusion modeling, the data provides the first evidence that mixed NT-induced locomotor efficacy may rely pivotally on sensory rerouting and pro-repair neuroplasticity to reactivate neurocircuits/central pattern generators. The finding describes a novel neurobiology mechanism underlying NT, which can be targeted for development of innovative neurotization therapies.

Early Effects of COVID-19 Pandemic on Neurosurgical Training in the United States: A Case Volume Analysis of 8 Programs.

OBJECTIVE: To determine the impact of the 2019 novel coronavirus disease (COVID-19) pandemic on operative case volume in 8 U.S. 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 through April 2020. Cases were grouped as elective cranial, elective spine, and nonelective emergent cases. Programs were surveyed regarding residents' perceptions of the impact of COVID-19 on surgical training, didactics, and research participation. Data were analyzed for individual programs and pooled across programs. RESULTS: Across programs, the 2019 monthly mean ± SD case volume was 211 ± 82; 2020 mean ± SD case volumes for January, February, March, and April were 228 ± 93, 214 ± 84, 180 ± 73, and 107 ± 45. Compared with 2019, March and April 2020 mean 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 required COVID-19 testing; however, to our knowledge, only 1 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 COVID-19 pandemic on residents' operative case volumes, identify deficiencies, and develop plans to mitigate any effects.

Fatal Penetrating Head Injuries Caused by Projectile Tear Gas Canisters.

BACKGROUND: Since their advent in the 1920s, tear gas canisters (TGCs) have been frequently used in crowd control. Few reports have documented nonpenetrating injuries attributed directly to TGCs. In this study, we report a case series of fatal penetrating head injuries caused by TGCs. METHODS: We conducted a retrospective chart review of all the patients who were admitted to the Neurosurgery Teaching Hospital in Baghdad, Iraq, since the start of the antigovernment protests (October 2019). All patients who suffered penetrating head trauma caused by TGCs were included in our study. We collected patient demographics, wound location, neurologic examination, computed tomography (CT) scan findings, surgical management, and clinical outcomes. RESULTS: We found 10 cases of penetrating head trauma caused by TGCs. All victims were men, with a mean age of 16 years (range, 14-19 years). The mean Glasgow Coma Scale score was 7 (range, 3-10). The neurologic examination revealed unilateral hemiplegia/hemiparesis and pupillary abnormality in 40% (n = 4) and 50% (n = 5) of the patients, respectively. CT scans revealed an extensive pattern of brain damage. Surgical intervention was done in 80% of cases (n = 8), which included removal of the TGC, wound debridement, and hemostasis. The in-hospital mortality rate was 100% (N = 10), with all fatalities occurring within 1-3 days of admission. CONCLUSIONS: TGCs have the potential to cause lethal penetrating head injuries, calling for a reevaluation of their safety and methods of use in terms of human health.

Republished: MRI SPACE sequence confirmation of occluded MCA M2 dissection stump masquerading as a ruptured MCA aneurysm.

Intracranial vascular pathologies often have overlapping clinical presentations. Dissected vessel occlusions and bifurcation aneurysms can appear similar on pretherapeutic imaging. The medical management of these two entities is drastically different. The patient is a 51-year-old man who presented with severe, sudden-onset headache. Initial presentation was consistent with a ruptured middle cerebral artery (MCA) aneurysm and surgical clipping was recommended. However, further review of radiographic findings could not definitively differentiate an aneurysmal origin of the symptoms as opposed to intracranial dissection followed by occlusion of the M2 branch of the MCA. MRI sampling perfection with application optimised contrasts using different flip angle evolution (SPACE) was performed and showed thin flow signalling distal to the dissected vessel stump confirming the diagnosis. Accurate diagnosis is a crucial step in directing treatment for intracranial vascular lesions. MRI SPACE is a simple tool in the diagnostic armamentarium to adequately direct treatment and avoid the potential for unnecessary interventions.

MRI SPACE sequence confirmation of occluded MCA M2 dissection stump masquerading as a ruptured MCA aneurysm.

Intracranial vascular pathologies often have overlapping clinical presentations. Dissected vessel occlusions and bifurcation aneurysms can appear similar on pretherapeutic imaging. The medical management of these two entities is drastically different. The patient is a 51-year-old man who presented with severe, sudden-onset headache. Initial presentation was consistent with a ruptured middle cerebral artery (MCA) aneurysm and surgical clipping was recommended. However, further review of radiographic findings could not definitively differentiate an aneurysmal origin of the symptoms as opposed to intracranial dissection followed by occlusion of the M2 branch of the MCA. MRI sampling perfection with application optimised contrasts using different flip angle evolution (SPACE) was performed and showed thin flow signalling distal to the dissected vessel stump confirming the diagnosis. Accurate diagnosis is a crucial step in directing treatment for intracranial vascular lesions. MRI SPACE is a simple tool in the diagnostic armamentarium to adequately direct treatment and avoid the potential for unnecessary interventions.

Continuous infusion of low-dose unfractionated heparin after aneurysmal subarachnoid hemorrhage: a preliminary study of cognitive outcomes.

OBJECTIVECognitive dysfunction occurs in up to 70% of aneurysmal subarachnoid hemorrhage (aSAH) survivors. Low-dose intravenous heparin (LDIVH) infusion using the Maryland protocol was recently shown to reduce clinical vasospasm and vasospasm-related infarction. In this study, the Montreal Cognitive Assessment (MoCA) was used to evaluate cognitive changes in aSAH patients treated with the Maryland LDIVH protocol compared with controls.METHODSA retrospective analysis of all patients treated for aSAH between July 2009 and April 2014 was conducted. Beginning in 2012, aSAH patients were treated with LDIVH in the postprocedural period. The MoCA was administered to all aSAH survivors prospectively during routine follow-up visits, at least 3 months after aSAH, by trained staff blinded to treatment status. Mean MoCA scores were compared between groups, and regression analyses were performed for relevant factors.RESULTSNo significant differences in baseline characteristics were observed between groups. The mean MoCA score for the LDIVH group (n = 25) was 26.4 compared with 22.7 in controls (n = 22) (p = 0.013). Serious cognitive impairment (MoCA ≤ 20) was observed in 32% of controls compared with 0% in the LDIVH group (p = 0.008). Linear regression analysis demonstrated that only LDIVH was associated with a positive influence on MoCA scores (ß = 3.68, p =0.019), whereas anterior communicating artery aneurysms and fevers were negatively associated with MoCA scores. Multivariable linear regression analysis resulted in all 3 factors maintaining significance. There were no treatment complications.CONCLUSIONSThis preliminary study suggests that the Maryland LDIVH protocol may improve cognitive outcomes in aSAH patients. A randomized controlled trial is needed to determine the safety and potential benefit of unfractionated heparin in aSAH patients.

Novel Treatments in Neuroprotection for Aneurysmal Subarachnoid Hemorrhage.

OPINION STATEMENT: New neuroprotective treatments aimed at preventing or minimizing "delayed brain injury" are attractive areas of investigation and hold the potential to have substantial beneficial effects on aneurysmal subarachnoid hemorrhage (aSAH) survivors. The underlying mechanisms for this "delayed brain injury" are multi-factorial and not fully understood. The most ideal treatment strategies would have the potential for a pleotropic effect positively modulating multiple implicated pathophysiological mechanisms at once. My personal management (RFJ) of patients with aneurysmal subarachnoid hemorrhage closely follows those treatment recommendations contained in modern published guidelines. However, over the last 5 years, I have also utilized a novel treatment strategy, originally developed at the University of Maryland, which consists of a 14-day continuous low-dose intravenous heparin infusion (LDIVH) beginning 12 h after securing the ruptured aneurysm. In addition to its well-known anti-coagulant properties, unfractionated heparin has potent anti-inflammatory effects and through multiple mechanisms may favorably modulate the neurotoxic and neuroinflammatory processes prominent in aneurysmal subarachnoid hemorrhage. In my personal series of patients treated with LDIVH, I have found significant preservation of neurocognitive function as measured by the Montreal Cognitive Assessment (MoCA) compared to a control cohort of my patients treated without LDIVH (RFJ unpublished data presented at the 2015 AHA/ASA International Stroke Conference symposium on neuroinflammation in aSAH and in abstract format at the 2015 AANS/CNS Joint Cerebrovascular Section Annual Meeting). It is important for academic physicians involved in the management of these complex patients to continue to explore new treatment options that may be protective against the potentially devastating "delayed brain injury" following cerebral aneurysm rupture. Several of the treatment options included in this review show promise and could be carefully adopted as the level of evidence for each improves. Other proposed neuroprotective treatments like statins and magnesium sulfate were previously thought to be very promising and to varying degrees were adopted at numerous institutions based on somewhat limited human evidence. Recent clinical trials and meta-analysis have shown no benefit for these treatments, and I currently no longer utilize either treatment as prophylaxis in my practice.