Mutant huntingtin disrupts mitochondrial proteostasis by interacting with TIM23.

Mutant huntingtin (mHTT), the causative protein in Huntington's disease (HD), associates with the translocase of mitochondrial inner membrane 23 (TIM23) complex, resulting in inhibition of synaptic mitochondrial protein import first detected in presymptomatic HD mice. The early timing of this event suggests that it is a relevant and direct pathophysiologic consequence of mHTT expression. We show that, of the 4 TIM23 complex proteins, mHTT specifically binds to the TIM23 subunit and that full-length wild-type huntingtin (wtHTT) and mHTT reside in the mitochondrial intermembrane space. We investigated differences in mitochondrial proteome between wtHTT and mHTT cells and found numerous proteomic disparities between mHTT and wtHTT mitochondria. We validated these data by quantitative immunoblotting in striatal cell lines and human HD brain tissue. The level of soluble matrix mitochondrial proteins imported through the TIM23 complex is lower in mHTT-expressing cell lines and brain tissues of HD patients compared with controls. In mHTT-expressing cell lines, membrane-bound TIM23-imported proteins have lower intramitochondrial levels, whereas inner membrane multispan proteins that are imported via the TIM22 pathway and proteins integrated into the outer membrane generally remain unchanged. In summary, we show that, in mitochondria, huntingtin is located in the intermembrane space, that mHTT binds with high-affinity to TIM23, and that mitochondria from mHTT-expressing cells and brain tissues of HD patients have reduced levels of nuclearly encoded proteins imported through TIM23. These data demonstrate the mechanism and biological significance of mHTT-mediated inhibition of mitochondrial protein import, a mechanism likely broadly relevant to other neurodegenerative diseases.

Pseudoanginal chest pain associated with vagal nerve stimulation: a case report.

BACKGROUND: Vagal nerve stimulation (VNS) can be an effective therapy for patients with epilepsy refractory to anti-epileptic drugs or intracranial surgery. While generally well tolerated, it has been associated with laryngospasm, hoarseness, coughing, dyspnea, throat and atypical chest pain, cardiac symptoms such as bradycardia and occasionally asystole. We report on a patient receiving vagal nerve stimulation who experienced severe typical anginal chest pain during VNS firing without any evidence of cardiac ischemia or dysfunction. Thus, the pain appeared to be neuropathic from the stimulation itself rather than nociceptive secondary to an effect on heart function. CASE PRESENTATION: A 29-year-old man, with a history of intractable frontal lobe epilepsy refractory to seven anti-epileptic medications and subsequent intracranial surgery, underwent VNS implantation without complications. On beginning stimulation, he began to have intermittent chest pain that corresponded temporally to his intermittent VNS firing. The description of his pain was pathognomonic of ischemic cardiac chest pain. On initial evaluation, he displayed Levine's sign and reported crushing substernal chest pain radiating to the left arm, as well as shortness of breath walking upstairs that improved with rest. He underwent an extensive cardiac workup, including 12-lead ECG, cardiac stress test, echocardiogram, 12-day ambulatory cardiac monitoring, and continuous ECG monitoring each with and without stimulation of his device. The workup was consistently negative. Inability to resolve the pain necessitated the disabling and eventual removal of the device. CONCLUSION: To our knowledge, this is the first report of pseudoanginal chest pain associated with VNS. This occurrence prompted our review of the mechanisms of cardiac chest pain and suggests that vagal afferents may convey anginal pain separately or in parallel with known spinal cord pain mechanisms. These insights into the physiology of chest pain may be of general interest and important to surgeons implanting VNS devices who may potentially encounter such symptoms.

Heparin Treatment in Aneurysmal Subarachnoid Hemorrhage: A Review of Human Studies.

Aneurysmal subarachnoid hemorrhage (aSAH) remains a significant cause of stroke disability despite gradual reductions in physical morbidity and mortality. Heparin is an effective anti-inflammatory agent and may potentially prevent delayed neurological injury in the days to weeks after the hemorrhage. Various human studies have shown the safety of a continuous infusion of low-dose unfractionated heparin in the setting of subarachnoid hemorrhage as well as its efficacy in minimizing delayed neurological deficits including symptomatic cerebral vasospasm, vasospasm-related infarction, and cognitive dysfunction. Studies have also shown mixed results with low-molecular-weight heparin usage in this patient population. Heparin treatment is not associated with significant hemorrhagic complications; however, vigilance is essential for early detection of heparin-induced thrombocytopenia in order to prevent devastating sequelae. Multicenter randomized controlled trials are necessary for objective characterization of the effects of heparin.

Dual role of mitochondria in producing melatonin and driving GPCR signaling to block cytochrome c release.

G protein-coupled receptors (GPCRs) are classically characterized as cell-surface receptors transmitting extracellular signals into cells. Here we show that central components of a GPCR signaling system comprised of the melatonin type 1 receptor (MT1), its associated G protein, and ß-arrestins are on and within neuronal mitochondria. We discovered that the ligand melatonin is exclusively synthesized in the mitochondrial matrix and released by the organelle activating the mitochondrial MT1 signal-transduction pathway inhibiting stress-mediated cytochrome c release and caspase activation. These findings coupled with our observation that mitochondrial MT1 overexpression reduces ischemic brain injury in mice delineate a mitochondrial GPCR mechanism contributing to the neuroprotective action of melatonin. We propose a new term, "automitocrine," analogous to "autocrine" when a similar phenomenon occurs at the cellular level, to describe this unexpected intracellular organelle ligand-receptor pathway that opens a new research avenue investigating mitochondrial GPCR biology.

Posterior reversible encephalopathy syndrome with lumbar drainage and surgery: coincidence or correlation? A case report.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is a rare neurological disorder usually associated with specific medical conditions that cause a disturbance of the CNS homeostasis. It has seldom been reported to be a consequence of an iatrogenic intervention causing intracranial hypotension. CASE PRESENTATION: We report the case of an individual 69-year-old male presenting with headache and blurred vision following cerebrospinal fluid (CSF) leak from resection of a sellar mass. The patient developed the condition following removal of the lumbar drain post-operatively. Magnetic Resonance Imaging showed bilateral occipital, parieto-occipital, and cerebellar T2 FLAIR hyper-intensities, suggesting a radiological diagnosis of posterior reversible encephalopathy syndrome (PRES). The patient's symptoms started to improve shortly afterwards and had completely resolved at 3 months follow-up. CONCLUSIONS: The absence of severe hypertension and presence of an intraoperative CSF leak requiring placement of the lumbar drain suggests that decreased CSF volume and associated reactive hyperemia could have a role in the pathophysiology of the disease.

National trends in cerebral bypass for unruptured intracranial aneurysms: a National (Nationwide) Inpatient Sample analysis of 1998-2015.

OBJECTIVEThe development and recent widespread dissemination of flow diverters may have reduced the utilization of surgical bypass procedures to treat complex or giant unruptured intracranial aneurysms (UIAs). The aim of this retrospective cohort study was to observe trends in cerebral revascularization procedures for UIAs in the United States before and after the introduction of flow diverters by using the National (Nationwide) Inpatient Sample (NIS).METHODSThe authors extracted data from the NIS database for the years 1998-2015 using the ICD-9/10 diagnostic and procedure codes. Patients with a primary diagnosis of UIA with a concurrent bypass procedure were included in the study. Outcomes and hospital charges were analyzed.RESULTSA total of 216,212 patients had a primary diagnosis of UIA during the study period. The number of patients diagnosed with a UIA increased by 128% from 1998 (n = 7718) to 2015 (n = 17,600). Only 1328 of the UIA patients (0.6%) underwent cerebral bypass. The percentage of patients who underwent bypass in the flow diverter era (2010-2015) remained stable at 0.4%. Most patients who underwent bypass were white (51%), were female (62%), had a median household income in the 3rd or 4th quartiles (57%), and had private insurance (51%). The West (33%) and Midwest/North Central regions (30%) had the highest volume of bypasses, whereas the Northeast region had the lowest (15%). Compared to the period 1998-2011, bypass procedures for UIAs in 2012-2015 shifted entirely to urban teaching hospitals (100%) and to an elective basis (77%). The median hospital stay (9 vs 3 days, p < 0.0001), median hospital charges ($186,746 vs $66,361, p < 0.0001), and rate of any complication (51% vs 17%, p < 0.0001) were approximately threefold higher for the UIA patients with bypass than for those without bypass.CONCLUSIONSDespite a significant increase in the diagnosis of UIAs over the 17-year study period, the proportion of bypass procedures performed as part of their treatment has remained stable. Therefore, advances in endovascular aneurysm therapy do not appear to have affected the volume of bypass procedures performed in the UIA population. The authors' findings suggest a potentially ongoing niche for bypass procedures in the contemporary treatment of UIAs.

Posterior lumbar dynamic stabilization instead of arthrodesis for symptomatic adjacent-segment degenerative stenosis: description of a novel technique.

OBJECTIVE The development of symptomatic adjacent-segment disease (ASD) is a well-recognized consequence of lumbar fusion surgery. Extension of a fusion to a diseased segment may only lead to subsequent adjacent-segment degeneration. The authors report the use of a novel technique that uses dynamic stabilization instead of arthrodesis for the surgical treatment of symptomatic ASD following a prior lumbar instrumented fusion. METHODS A cohort of 28 consecutive patients was evaluated who developed symptomatic stenosis immediately adjacent to a previous lumbar instrumented fusion. All patients had symptoms of neurogenic claudication refractory to nonsurgical treatment and were surgically treated with decompression and dynamic stabilization instead of extending the fusion construct using a posterior lumbar dynamic stabilization system. Preoperative symptoms, visual analog scale (VAS) pain scores, and perioperative complications were recorded. Clinical outcome was gauged by comparing VAS scores prior to surgery and at the time of last follow-up. RESULTS The mean follow-up duration was 52 months (range 17-94 months). The mean interval from the time of primary fusion surgery to the dynamic stabilization surgery was 40 months (range 10-96 months). The mean patient age was 51 years (range 29-76 years). There were 19 (68%) men and 9 (32%) women. Twenty-three patients (82%) presented with low-back pain at time of surgery, whereas 24 patients (86%) presented with lower-extremity symptoms only. Twenty-four patients (86%) underwent operations that were performed using single-level dynamic stabilization, 3 patients (11%) were treated at 2 levels, and 1 patient underwent 3-level decompression and dynamic stabilization. The most commonly affected and treated level (46%) was L3-4. The mean preoperative VAS pain score was 8, whereas the mean postoperative score was 3. No patient required surgery for symptomatic degeneration rostral to the level of dynamic stabilization during the follow-up period. CONCLUSIONS The use of posterior lumbar dynamic stabilization may offer a valid and safe option for the management of patients who develop ASD rostral to a previously instrumented arthrodesis. The technique may serve as an alternative to multilevel arthrodesis in this patient population. By implanting a dynamic stabilization device instead of an extension of a rigid construct, this might translate into a reduction in the development of yet another level of ASD.

Perioperative stroke after carotid endarterectomy: etiology and implications.

BACKGROUND: Carotid endarterectomy (CEA) is the procedure of choice for reducing the risk of stroke in both symptomatic and asymptomatic carotid artery stenoses. Stroke is associated with significant morbidity and mortality peri-operatively (2-3 %). Our primary aim is to evaluate the etiology of these strokes after CEA and their impact on morbidity by comparing the length of stay in the hospital. METHODS: A total of 584 patients with documented neurological status evaluations who underwent CEAs were included in the study. Neurophysiological monitoring data was obtained during CEA for carotid stenosis included eight-channel electroencephalography (EEG) and upper extremity somatosensory evoked potentials (SSEPs). RESULTS: Twenty-one (3.595 %) patients had strokes in the perioperative period and they were more likely to have left-sided surgery (p = 0.008), intraoperative monitoring (IOM) changes (p < 0.001), an intraoperative shunt placed (p = 0.0002) or a hospital stay longer than 5 days (p = 0.0042). Unilateral anterior circulation ischemic stroke were the most common in our series. In a logistic regression model, left-sided surgery was shown to be 4.78 times more likely to be associated with perioperative stroke (1.50-15.27; p = 0.008) while intraoperative shunts were 11.85 times more likely to have strokes (3.97-35.34; p < 0.0001). Patients with stenosis greater than 70 % were 6.67 times less likely to have a stroke (0.04-0.59; p = 0.007). CONCLUSIONS: Ischemic anterior circulation strokes are the most common type of post-operative neurological changes in patients undergoing CEA. Intraoperative shunt placement was a strong predictor of perioperative strokes. Since shunts are only placed following intraoperative monitoring changes, SSEPs and EEG can therefore function as a biomarker of cerebral hypo-perfusion.

Acute and Long-Term Management of Blunt Cerebrovascular Injury at a Quaternary Referral Level 1 Trauma Center: The Memphis Experience and Comparison of a New Scoring System.

BACKGROUND AND OBJECTIVES: The management of blunt cerebrovascular injuries (BCVIs) remains an important topic within trauma and neurosurgery today. There remains a lack of consensus within the literature and significant variation across institutions. The purpose of this study was to evaluate management of BCVI at a large, tertiary referral trauma center. METHODS: Institutional Review Board approval was obtained to conduct a retrospective review of patients with BCVI at our Level 1 Trauma Center. Computed tomography angiography was used to identify BCVI for each patient. Patient information was collected, and statistical analysis was performed. With the included risk factors for ischemic complications, a novel scoring system based on ischemic risk, the "Memphis Score," was developed and evaluated to grade BCVI. RESULTS: Two hundred seventeen patients with BCVI from July 2020 to August 2022 were identified. The most common mechanism of injury was motor vehicle collision (141, 65.0%). Vertebral arteries were the most common vessel injured (136, 51.1%) with most injuries occurring at a high cervical location (101, 38.0%). Denver Grade 1 injuries (89, 33.5%) and a Memphis Score of 1 were most frequent (172, 64.6%), and initial anticoagulation with heparin drip was initiated 56.7% of the time (123). Endovascular treatment was required in 24 patients (11.1%) and was usually performed in the first 48 hours (15, 62.5%). While Denver Grade (P = .019) and Memphis Score (P < .00001) were significantly higher in those patients undergoing endovascular treatment, only the Memphis Score demonstrated a significant difference between those patients who had stroke or worsening on follow-up imaging and those who did not (P = .0009). CONCLUSION: Although BCVI management has improved since early investigative efforts, institutions must evaluate and share their data to help clarify outcomes. The novel "Memphis Score" presents a standardized framework to communicate ischemic risk and guide management of BCVI.

Microsurgical resection of a ruptured right peri-ventricular brain arteriovenous malformation with preoperative embolization.

A 41-year-old female presented with a headache and left inferior quadrantanopia. Imaging demonstrated a clot spanning the atrium of the ventricle to the superior parietal lobule (SPL), with a small arteriovenous malformation (AVM) nidus outside the atrium of the ventricle. The nidus was supplied by parieto-occipital arterial (P4) feeders with a single atrial draining vein. Pre-operative embolization of a pedicle with Onyx provided a surgical marker. A parietal craniotomy was performed with a trans-cortical SPL approach. During AVM resection, the draining vein was injured, which was stabilized using a temporary clip to "spot weld" the defect and continue nidus dissection with patent venous outflow. After careful dissection, coagulation, and division of all the arterial feeders, the AVM was mobilized and the draining vein was clipped, coagulated, and divided. Follow-up indocyanine green angiography and cerebral angiography both confirmed complete resection of the AVM. The patient consented to the procedure and to publication.

Primary Spinal Glioblastoma Mimicking Neuroschistosomiasis: A Case Report.

Primary glioblastoma of the spinal cord (sGB) is a rare and challenging diagnosis. In the diagnostic algorithm, reversible causes should be considered while the diagnosis of sGB is under evaluation. We present a case of cervical sGB mimicking neuroschistosomiasis. A 21-year-old Somali man presented with neck pain, sensory disturbances, and spastic tetraplegia. Cervical spine magnetic resonance imaging with contrast showed a heterogeneously enhancing intramedullary mass spanning from the level of the C1 to T3 vertebrae. Cerebrospinal fluid analysis showed a lymphocytic predominance and elevated protein. Due to the patient's history of poorly treated schistosomiasis, praziquantel and dexamethasone were initiated while the diagnostic work-up was completed. Three days after the patient was discharged to a rehabilitation facility where he experienced worsened motor function with radiographic progression of the lesion and increased cord edema. The patient underwent a surgical biopsy which confirmed a diagnosis of primary sGB. sGB is an unusual diagnosis that can masquerade as a non-neoplastic lesion. However, the diagnosis of sGB should be considered in patients with an intramedullary spinal cord lesion who exhibit rapid radiographic and clinical progression.

Hypoxia-inducible factor prolyl hydroxylase domain (PHD) inhibition after contusive spinal cord injury does not improve locomotor recovery.

Traumatic spinal cord injury (SCI) is a devastating neurological condition that involves both primary and secondary tissue loss. Various cytotoxic events including hypoxia, hemorrhage and blood lysis, bioenergetic failure, oxidative stress, endoplasmic reticulum (ER) stress, and neuroinflammation contribute to secondary injury. The HIF prolyl hydroxylase domain (PHD/EGLN) family of proteins are iron-dependent, oxygen-sensing enzymes that regulate the stability of hypoxia inducible factor-1α (HIF-1α) and also mediate oxidative stress caused by free iron liberated from the lysis of blood. PHD inhibition improves outcome after experimental intracerebral hemorrhage (ICH) by reducing activating transcription factor 4 (ATF4)-driven neuronal death. As the ATF4-CHOP (CCAAT-enhancer-binding protein homologous protein) pathway plays a role in the pathogenesis of contusive SCI, we examined the effects of PHD inhibition in a mouse model of moderate T9 contusive SCI in which white matter damage is the primary driver of locomotor dysfunction. Pharmacological inhibition of PHDs using adaptaquin (AQ) moderately lowers acute induction of Atf4 and Chop mRNAs and prevents the acute decline of oligodendrocyte (OL) lineage mRNAs, but does not improve long-term recovery of hindlimb locomotion or increase chronic white matter sparing. Conditional genetic ablation of all three PHD isoenzymes in OLs did not affect Atf4, Chop or OL mRNAs expression levels, locomotor recovery, and white matter sparing after SCI. Hence, PHDs may not be suitable targets to improve outcomes in traumatic CNS pathologies that involve acute white matter injury.

Woven Endobridge device for treatment of dissection-related PICA aneurysm.

Ruptured vertebrobasilar dissecting aneurysms require urgent, often challenging treatment as they have with a high re-hemorrhage rate within the first 24 hours. The patient is a 57-year-old woman who presented with severe-sudden onset headache. Further work up showed a ruptured dissecting aneurysm of the caudal loop of the posterior inferior cerebellar artery (PICA) with associated narrowing distally, in the ascending limb. The aneurysm was immediately occluded with a Woven Endobridge (WEB) device (MicroVention, Tustin, CA, USA) while flow diversion treatment of the diseased ascending limb was postponed. Follow-up angiography three months later showed complete occlusion of the aneurysm, as well as healing of the diseased distal vessel, obviating the need for further intervention. WEB embolization of a ruptured dissecting posterior circulation aneurysm provided an excellent outcome for this patient.

Minimally Invasive Endoscopy for Acute Subdural Hematomas: A Report of 3 Cases.

BACKGROUND: Acute subdural hematomas (aSDHs) occur in approximately 10% to 20% of all closed head injury and represent a significant cause of morbidity and mortality in traumatic brain injury patients. Conventional craniotomy is an invasive intervention with the potential for excess blood loss and prolonged postoperative recovery time. OBJECTIVE: To evaluate the outcomes of minimally invasive endoscopy for evacuation of aSDHs in a pilot feasibility study. METHODS: We retrospectively reviewed the records of consecutive patients with aSDHs who underwent surgical treatment at our institution with minimally invasive endoscopy using the Apollo/Artemis Neuro Evacuation Device (Penumbra, Alameda, California) between April 2015 and July 2018. RESULTS: The study cohort comprised three patients. The Glasgow Coma Scale on admission was 15 for all 3 patients, median preoperative hematoma volume was 49.5 cm3 (range 44-67.8 cm3), median postoperative degree of hematoma evacuation was 88% (range 84%-89%), and median modified Rankin Scale at discharge was 1 (range 0-3). CONCLUSION: Endoscopic evacuation of aSDHs can be a safe and effective alternative to craniotomy in appropriately selected patients. Further studies are needed to refine the selection criteria for endoscopic aSDH evacuation and evaluate its long-term outcomes.

Low-Dose Intravenous Heparin Infusion After Aneurysmal Subarachnoid Hemorrhage is Associated With Decreased Risk of Delayed Neurological Deficit and Cerebral Infarction.

BACKGROUND: Patients who survive aneurysmal subarachnoid hemorrhage (aSAH) are at risk for delayed neurological deficits (DND) and cerebral infarction. In this exploratory cohort comparison analysis, we compared in-hospital outcomes of aSAH patients administered a low-dose intravenous heparin (LDIVH) infusion (12 U/kg/h) vs those administered standard subcutaneous heparin (SQH) prophylaxis for deep vein thrombosis (DVT; 5000 U, 3 × daily). OBJECTIVE: To assess the safety and efficacy of LDIVH in aSAH patients. METHODS: We retrospectively analyzed 556 consecutive cases of aSAH patients whose aneurysm was secured by clipping or coiling at a single institution over a 10-yr period, including 233 administered the LDIVH protocol and 323 administered the SQH protocol. Radiological and outcome data were compared between the 2 cohorts using multivariable logistic regression and propensity score-based inverse probability of treatment weighting (IPTW). RESULTS: The unadjusted rate of cerebral infarction in the LDIVH cohort was half that in SQH cohort (9 vs 18%; P = .004). Multivariable logistic regression showed that patients in the LDIVH cohort were significantly less likely than those in the SQH cohort to have DND (odds ratio (OR) 0.53 [95% CI: 0.33, 0.85]) or cerebral infarction (OR 0.40 [95% CI: 0.23, 0.71]). Analysis following IPTW showed similar results. Rates of hemorrhagic complications, heparin-induced thrombocytopenia and DVT were not different between cohorts. CONCLUSION: This cohort comparison analysis suggests that LDIVH infusion may favorably influence the outcome of patients after aSAH. Prospective studies are required to further assess the benefit of LDIVH infusion in patients with aSAH.

Inverse National Trends in Decompressive Craniectomy versus Endovascular Thrombectomy for Stroke.

OBJECTIVE: Endovascular thrombectomy (ET) for acute large vessel occlusion reduces infarct size, and it should hypothetically decrease the incidence of major ischemic strokes requiring decompressive craniectomy (DC). The aim of this retrospective cohort study is to determine trends in the utilization of ET versus DC for stroke in the United States over a 10-year span. METHODS: We extracted data from the Nationwide Inpatient Sample using International Classification of Diseases-9/10 codes from 2006-2016. Patients with a primary diagnosis of stroke were included. Baseline demographics, outcomes, and hospital charges were analyzed. RESULTS: The study cohort comprised 14,578,654 patients diagnosed with stroke. During the study period, DC and ET were performed in 124,718 and 62,637 patients, respectively. The number of stroke patients who underwent either ET or DC increased by 266% from 2006 to 2016. During that time period, the ET utilization rate increased (0.19% in 2006 to 14.07% in 2016, P < 0.0004), whereas the DC utilization rate decreased (7.07% in 2006 to 6.43% in 2016, P < 0.0001). In 2015, the utilization rate of ET (9.73%) exceeded that of DC (9.67%). ET-treated patients had shorter hospitalization durations (mean 8.8 vs. 16.8 days, P < 0.0001), lower mortality (16.2% vs. 19.3%), higher likelihood of discharge home (27.1% vs. 24.1%, P < 0.0001), and reduced hospital charges (mean $189,724 vs. $261,314, P < 0.0001). CONCLUSIONS: We identified an inverse relationship between national trends in rising ET and diminishing DC utilization for stroke treatment over a recent decade. Although direct causation cannot be inferred, our findings suggest that ET curtails the necessity for DC.

Treadmill-Based Gait Kinematics in the Yucatan Mini Pig.

Yucatan miniature pigs (YMPs) are similar to humans in spinal cord size as well as physiological and neuroanatomical features, making them a useful model for human spinal cord injury. However, little is known regarding pig gait kinematics, especially on a treadmill. In this study, 12 healthy YMPs were assessed during bipedal and/or quadrupedal stepping on a treadmill at six speeds (1.0, 1.5, 2.0, 2.5, 3.0, and 3.5 km/h). Kinematic parameters, including limb coordination and proximal and distal limb angles, were measured. Findings indicate that YMPs use a lateral sequence footfall pattern across all speeds. Stride and stance durations decreased with increasing speed whereas swing duration showed no significant change. Across all speeds assessed, no significant differences were noted between hindlimb stepping parameters for bipedal or quadrupedal gait with the exception of distal limb angular kinematics. Specifically, significant differences were observed between locomotor tasks during maximum flexion (quadrupedal > bipedal), total excursion (bipedal > quadrupedal), and the phase relationship between the timing of maximum extension between the right and left hindlimbs (bipedal > quadrupedal). Speed also impacted maximum flexion and right-left phase relationships given that significant differences were found between the fastest speed (3.5 km/h) relative to each of the other speeds. This study establishes a methodology for bipedal and quadrupedal treadmill-based kinematic testing in healthy YMPs. The treadmill approach used was effective in recruiting primarily the spinal circuitry responsible for the basic stepping patterns as has been shown in cats. We recommend 2.5 km/h (0.7 m/sec) as a target walking gait for pre-clinical studies using YMPs, which is similar to that used in cats.

Intracranial hemorrhage in a young COVID-19 patient.

COVID-19 patients are increasingly understood to develop multisystem manifestations, including neurologic involvement. We report the case of a 42-year old COVID-19 positive patient with a fatal intracerebral hemorrhage (ICH). The patient presented with fever and dyspnea, requiring intubation due to medical complications. After prolonged sedation and anticoagulation, the patient suddenly developed bilaterally fixed and dilated pupils, caused by a right-sided intracranial hemorrhage with uncal herniation. The course of this case illustrates the delicate balance between hypercoagulability and coagulation factor depletion; especially in the intubated and sedated patient, in whom regular neurological assessments are impeded. As we expand our understanding of the neurological ramifications of COVID-19, clinicians need to be increasingly aware of the precarious coagulation balance.

Anomalous Origin of the Anterior Choroidal Artery Proximal to an Ipsilateral Fetal Posterior Cerebral Artery: Case Report of an Extremely Rare Anatomic Variant and Discussion of its Clinical Implications.

The anterior choroidal artery (AChA) supplies important cerebral structures such as the internal capsule, optic tract, and lateral geniculate body. It is normally a branch of the communicating segment of the internal carotid artery (ICA) with significant neurological symptomatology if injured. Typically, the AChA originates distal to the posterior communicating artery (PCoA), but rare variants have previously been described. Such anatomical differences are particularly important entities, especially in the context of neuroendovascular procedures, as inadvertent damage to these arteries can have devastating consequences. In this case report, we present an unusual anatomical pattern of the right AChA arising proximal to an ipsilateral fetal PCA.

Traumatic Ventral Cervical Spinal Cord Herniation: A Case Report.

Spinal cord herniation (SCH) is an uncommon traumatic event that should be considered in patients with vertebral fractures who develop an unusual constellation of autonomic and motor deficits. Herein, we describe a case of rapidly deteriorating neurological function following cervical spine fracture including sequelae such as bilateral lower-extremity weakness, loss of upper extremity motor function, and priapism. Decompression of the spinal cord allowed for the identification of the unusual herniation of the spinal cord and prevention of any further worsening of the neurological injury. Hyperflexion of the cervical spine upon traumatic impact provided the impetus for vertebral retropulsion and subsequent incarceration of the spinal cord. This phenomenon should be considered in the setting of acute traumatic injury to the cervical spinal cord. Surgical intervention is likely to allow the preservation of the remaining neurological function.