Distal Spinal Cord Research Articles

Next-Generation Frozen Elephant Trunk Technique in the Era of Precision Medicine.

The frozen elephant trunk (FET) technique can be applied to extensive aortic pathology, including lesions in the aortic arch and proximal descending thoracic aorta. FET is useful for tear-oriented surgery in dissections, managing malperfusion syndrome, and promoting positive aortic remodeling. Despite these benefits, complications such as distal stent-induced new entry and spinal cord ischemia can pose serious problems with the FET technique. To prevent these complications, careful sizing and planning of the FET are crucial. Additionally, since the FET technique involves total arch replacement, meticulous surgical skills are essential, particularly for young surgeons. In this article, we propose several techniques to simplify surgical procedures, which may lead to better outcomes for patients with extensive aortic pathology. In the era of precision medicine, the next-generation FET device could facilitate the treatment of complex aortic diseases through a patient-tailored approach.

Disruption of Core Stress Granule Protein Aggregates Promotes CNS Axon Regeneration.

Depletion or inhibition of core stress granule proteins, G3BP1 in mammals and TIAR-2 in C. elegans , increases axon regeneration in injured neurons that show spontaneous regeneration. Inhibition of G3BP1 by expression of its acidic or 'B-domain' accelerates axon regeneration after nerve injury bringing a potential therapeutic intervention to promote neural repair in the peripheral nervous system. Here, we asked if G3BP1 inhibition is a viable strategy to promote regeneration in the injured mammalian central nervous system where axons do not regenerate spontaneously. G3BP1 B-domain expression was found to promote axon regeneration in both the mammalian spinal cord and optic nerve. Moreover, a cell permeable peptide to a subregion of G3BP1's B-domain (rodent G3BP1 amino acids 190-208) accelerated axon regeneration after peripheral nerve injury and promoted the regrowth of reticulospinal axons into the distal transected spinal cord through a bridging peripheral nerve graft. The rodent and human G3BP1 peptides promoted axon growth from rodent and human neurons cultured on permissive substrates, and this function required alternating Glu/Asp-Pro repeats that impart a unique predicted tertiary structure. These studies point to G3BP1 granules as a critical impediment to CNS axon regeneration and indicate that G3BP1 granule disassembly represents a novel therapeutic strategy for promoting neural repair after CNS injury.

Feasibility of diffusion tensor imaging in cervical spondylotic myelopathy using MUSE sequence

The most frequent type of spinal cord injury is cervical spondylotic myelopathy (CSM). Conventional structural magnetic resonance imaging (MRI) is the gold diagnosis standard for CSM. Diffusion tensor imaging (DTI) could reflect microstructural changes in the spinal cord by tracing water molecular diffusion in early stages of CSM. However, due to the complex local anatomical structure and small field of view of the spinal cord, the imaging effect of traditional DTI imaging on the spinal cord is limited. MUSE (MUltiplexed Sensitivity-Encoding) -DTI is a novel diffusion-weighted imaging (DWI) sequence that achieves higher signal intensity through multiple excitation acquisition. MUSE sequence may improve the quality of spinal cord DTI imaging. Prospective study. This study aimed to investigate the clinical diagnosis value of a novel protocol of MUSE-DTI in patients with cervical spondylotic myelopathy (CSM). From August 2021 to March 2022, a total of 60 subjects (22-71 years) were enrolled, including 51 CSM patients (22 males, 29 females) and 9 healthy subjects (4 males and 5 females). Each subject underwent a MUSE-DTI examination and a clinical Japanese Orthopedic Association (JOA) scale. We measured values of FA (Fractional Anisotropy), MD (Mean Diffusivity), AD (Axial Diffusivity), and RD (Radial Diffusivity), and collected the clinical JOA scores of each subject before the MR examination. A 3.0T MR scanner (Signa Architect, GE Healthcare) performed the MUSE-DTI sequence on each subject. The cervical canal stenosis of subjects was classified from grade 0 to grade Ⅲ according to the method of an MRI grading system. FA, MD, AD, and RD maps were generated by postprocessing MUSE-DTI data on the GE workstation. Regions of interest (ROIs) were manually drawn at the C2 vertebral body level and C2/3-C6/7 intervertebral disc levels by covering the whole spinal cord. The clinical severity of myelopathy of subjects was assessed by the clinical Japanese Orthopedic Association scale (JOA). MUSE-DTI can acquire a high-resolution diffusion image compared to traditional DTI. The FAMCL values showed a decreasing trend from grade 0 to grade Ⅲ, while the MDMCL, ADMCL, and RDMCL values showed an overall increasing trend. Significant differences in MDMCL, ADMCL, and RDMCL values were found between adjacent groups among grades Ⅰ-Ⅲ (p<.05). The ADC2 values in CSM patients (grade I-Ⅲ) were significantly lower than in healthy individuals (grade 0) (p=.019). The clinical JOA score has a significant correlation with FAMCL (p=.035), MDMCL (p<.001), ADMCL (p<.001), and RDMCL (p<.001) values. MUSE-DTI displayed a better image quality compared to traditional DTI. MUSE-DTI parameters displayed a grade-dependent trend. All the MUSE-DTI parameters at MCL were correlated with the clinical JOA scores. The ADC2 values can reflect the secondary damage of distal spinal cord. Therefore, MUSE-DTI could be a reliable biomarker for clinical auxiliary diagnosis of spinal cord injury severity in cervical spondylotic myelopathy.

Intravenous Administration of Human Muse Cells Ameliorates Deficits in a Rat Model of Subacute Spinal Cord Injury.

Multilineage-differentiating stress-enduring (Muse) cells are newly established pluripotent stem cells. The aim of the present study was to examine the potential of the systemic administration of Muse cells as an effective treatment for subacute SCI. We intravenously administered the clinical product "CL2020" containing Muse cells to a rat model two weeks after mid-thoracic spinal cord contusion. Eight experimental animals received CL2020, and twelve received the vehicle. Behavioral analyses were conducted over 20 weeks. Histological evaluations were performed. After 20 weeks of observation, diphtheria toxin was administered to three CL2020-treated animals to selectively ablate human cell functions. Hindlimb motor functions significantly improved from 6 to 20 weeks after the administration of CL2020. The cystic cavity was smaller in the CL2020 group. Furthermore, larger numbers of descending 5-HT fibers were preserved in the distal spinal cord. Muse cells in CL2020 were considered to have differentiated into neuronal and neural cells in the injured spinal cord. Neuronal and neural cells were identified in the gray and white matter, respectively. Importantly, these effects were reversed by the selective ablation of human cells by diphtheria toxin. Intravenously administered Muse cells facilitated the therapeutic potential of CL2020 for severe subacute spinal cord injury.

Single-institution Series of Hirayama Disease in North America.

A retrospective chart review. The aims of this study were to review pathophysiology, workup, and treatment for Hirayama disease (HD); and to assess outcomes from a single institution. HD is a rare, painless, cervical myelopathy with distal upper extremity weakness, muscle wasting, and spinal cord atrophy. Disease progression-a consequence of repeat flexion injury-occurs up to 5 years from the initial diagnosis. Single-institution review of pediatric HD patients from 2010 to 2020. Patients (n=10 male, n=2 female) presented in the second decade (14-20y) with painless progressive distal upper extremity weakness and atrophy without sensory loss. Electromyography (n=12) demonstrated denervation in C7-T1 myotomes and flexion/extension magnetic resonance imaging showed focal cord atrophy and anterior displacement of the posterior dura with epidural enhancement in flexion. Treatment included observation and external orthoses (n=9) and anterior cervical discectomy with fusion (n=3). One of the 9 patients managed conservatively experienced further deterioration; no patient who underwent anterior cervical discectomy with fusion progressed. Patients with HD require a multidisciplinary approach to diagnosis and treatment to preserve function. Treatment is preventive and aims to minimize flexion injury by inhibiting motion across involved joints. First-line management is avoidance of neck flexion and use of rigid orthosis; in cases of failed conservative management and/or rapid clinical deterioration, surgical fixation can be offered.

Intraoperative demonstration of reduced distal spinal cord stiffness following untethering of the spinal cord using ultrasound shear wave elastography (SWE)

Intraoperative demonstration of reduced distal spinal cord stiffness following untethering of the spinal cord using ultrasound shear wave elastography (SWE)

Spinal cord infarction after transcatheter aortic valve replacement: a case report (P12-7.005)

<h3>Objective:</h3> To describe a case of spinal cord infarct after transcatheter aortic valve replacement (TARV) <h3>Background:</h3> Spinal cord infarct is a well-known complication of thoracoabdominal aneurysms open repair, with an approximate incidence of 8%. TARV is a frequently used option for high-risk surgical patients with severe aortic stenosis. Because the descending aorta is not involved in TARV, post procedure spinal cord infarct is considered rare. We report a case of infarct of the thoracic and lumbar spinal cord after TARV. <h3>Design/Methods:</h3> Case report <h3>Results:</h3> 68-year-old male with history of heart failure, end stage kidney disease (ESRD), coronary artery bypass, and renal cell carcinoma was electively admitted for TARV for severe aortic stenosis. CT angiogram (CTA) of abdomen revealed severe calcified atherosclerotic disease throughout the entire vascular system from the distal abdominal aorta to toes. TARV procedure lasted about 30 minutes with no significant reported blood loss. Immediately after, he reported severe low back pain and inability to move his legs. Bladder control was unclear (ESRD), and bowel function was preserved. On exam, sensation to light touch was preserved throughout, strength was preserved in upper extremities, but absent in lower extremities. His patellar, Achilles and plantar reflexes were absent. Magnetic resonance imaging (MRI) of spine revealed diffuse long segment signal abnormality and mild edema involving the distal thoracic spinal cord extending into the conus consistent with spinal cord infarct. The patient remained paraplegic at discharge. <h3>Conclusions:</h3> To the authors knowledge, there is only one other case report of paraplegia secondary to TARV. That patient also showed diffuse arteriosclerosis of the thoracic and abdominal arteries. Although considered rare, it is important that the clinician is aware of this devastating complication of TARV and counsel patients appropriately, especially in patients with severe aortic arteriosclerosis. <b>Disclosure:</b> Dr. D’Aguiar Rosa has nothing to disclose. Dr. Brown has nothing to disclose. Dr. Yousaf has nothing to disclose. Dr. Sagi has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for SK Life Sciences.

Acute Transcriptomic and Epigenetic Alterations at T12 After Rat T10 Spinal Cord Contusive Injury.

Spinal cord injury is a severely debilitating condition affecting a significant population in the USA. Spinal cord injury patients often have increased risk of developing persistent neuropathic pain and other neurodegenerative conditions beyond the primary lesion center later in their life. The molecular mechanism conferring to the "latent" damages at distal tissues, however, remains elusive. Here, we studied molecular changes conferring abnormal functionality at distal spinal cord (T12) beyond the lesion center (T10) by combining next-generation sequencing (RNA- and bisulfite sequencing), super-resolution microscopy, and immunofluorescence staining at 7days post injury. We observed significant transcriptomic changes primarily enriched in neuroinflammation and synaptogenesis associated pathways. Transcription factors (TFs) that regulate neurogenesis and neuron plasticity, including Egr1, Klf4, and Myc, are significantly upregulated. Along with global changes in chromatin arrangements and DNA methylation, including 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC), bisulfite sequencing further reveals the involvement of DNA methylation changes in regulating cytokine, growth factor, and ion channel expression. Collectively, our results pave the way towards understanding transcriptomic and epigenomic mechanism in conferring long-term disease risks at distal tissues away from the primary lesion center and shed light on potential molecular targets that govern the regulatory mechanism at distal spinal cord tissues.

Lower Body Perfusion Reduces the Morbidity of Postoperative Acute Kidney Injury in Type A Dissection: A Propensity-Matched Analysis.

Lower body perfusion (LBP) is a technique used to provide blood perfusion to distal organs and spinal cord during circulatory arrest. However, the effect of LBP on the prognosis of aortic arch surgery, especially on postoperative renal function, remains unclear. A total of 304 patients with acute type A aortic dissection who underwent total aortic arch replacement combined with frozen elephant trunk implantation between May 2016 and December 2021 were retrospectively analyzed. The patients were divided into LBP group (group L, n=85) and non-LBP group (group NL, n=219). Routine lower body circulatory arrest was applied during operation in group NL, and antegrade LBP combined was applied during operation in group L. Perioperative data were recorded. Propensity score matching was used for statistical analysis. After propensity score matching, 85 pairs of patients were successfully matched. Two groups significantly differed in circulatory arrest time (six minutes vs. 30 minutes, P=0.000), cross-clamping time (101 minutes vs. 92 minutes, P=0.010), minimum nasopharyngeal temperature (29.4ºC vs. 27.2ºC, P=0.000), and highest lactate value during cardiopulmonary bypass (2.3 μmol/L vs. 4.1 μmol/L, P=0.000). Considering the postoperative indicators, the drainage volume (450 mL vs. 775 mL, P=0.000) and the incidence of level I acute kidney injury (23.5% vs. 32%, P=0.046) in group L was lower than those in group NL. LBP resulted as a safe and feasible approach in aortic arch surgery, as it could significantly shorten the circulatory arrest time, which might reduce the incidence of postoperative level I acute kidney injury.

Astrocyte heterogeneity within white matter tracts and a unique subpopulation of optic nerve head astrocytes.

Much of what we know about astrocyte form and function is derived from the study of gray matter protoplasmic astrocytes, whereas white matter fibrous astrocytes remain relatively unexplored. Here, we used the ribotag approach to isolate ribosome-associated mRNA and investigated the transcriptome of uninjured fibrous astrocytes from three regions: unmyelinated optic nerve head, myelinated optic nerve proper, and corpus callosum. Astrocytes from each region were transcriptionally distinct and we identified region-specific astrocyte genes and pathways. Energy metabolism, particularly oxidative phosphorylation and mitochondrial protein translation emerged as key differentiators of astrocyte populations. Optic nerve astrocytes expressed higher levels of neuroinflammatory pathways than corpus callosum astrocytes and we further identified CARTPT as a new marker of optic nerve head astrocytes. These previously uncharacterized transcriptional profiles of white matter astrocyte types reveal their functional diversity and a greater heterogeneity than previously appreciated.

Lumbar cistern Candida intradural abscess following epidural anesthesia

This report describes a case of an immunocompetent patient with an intradural abscess from Candida dubliniensis. The majority of fungal spine infections, although rare in general, are due to Aspergillus or C. albicans through systemic fungemia. To date, there have only been two reports of spondylodiscitis from C. dubliniensis. A 37-year-old immunocompetent female patient presented to the neurosurgical service for worsening headaches with nausea, vomiting, vision changes, and weight loss. MRI studies showed diffuse leptomeningeal enhancement of the distal spinal cord, conus medullaris, and nerve roots of the cauda equina extending beyond the neural foramina bilaterally. She had persistent symptoms and no clear diagnosis on lumbar puncture or systemic testing therefore L5-S1 laminectomy for an intradural tissue biopsy was performed. During surgery, cultures were taken and grew colonies of C. dubliniensis. This organism has been reported rarely in the literature as being an infectious agent, thus diagnosing remains a challenge but should be considered in patients with a suggestive history.

Physiologically intense FDG uptake of distal spinal cord on total-body PET/CT.

Physiologically mild-to-moderate FDG uptake of the spinal cord was reported. However, we noticed intense FDG uptake of distal spinal cord in several patients without definite spinal cord lesions on total-body PET/CT. Thus, this study aimed to investigate the frequency, pattern, intensity, and associations of FDG uptake in such cases on total-body PET/CT. The clinical characteristics of age, gender, body mass index (BMI), lower extremity symptom, diabetes, and fasting blood glucose level, and total-body FDG PET/CT metabolic parameters of maximum standard uptake value (SUVmax), SUVmax of lean body mass (SUVlbm), and SUVmax of body surface area (SUVbsa), were retrospectively analyzed in 527 patients without definite spinal cord lesions. Intense FDG uptake was defined as greater than liver glucometabolism on visual analysis, and T5 cord was selected as cord background. Intense FDG uptake of distal spinal cord was observed in 87 out of 527 patients (16.5%) and involved with 2-3 vertebral segments including T11-T12 in 33 cases (38.0%), T12-L1 in 29 (33.3%), and T11-L1 in 25 (28.7%). No lesions were demonstrated on follow-up physical examinations, MRI or contrast-enhanced CT in these 87 cases with intense FDG accumulation in the distal spinal cord. The median SUVmax, SUVlbm, and SUVbsa of distal spinal cord with intense FDG uptake were 3.8 (2.7-5.5), 2.9 (2.2-4.3), and 1.0 (0.7-1.6), respectively. Significant differences in SUVmax, SUVlbm, and SUVbsa of distal cord and cord background were found between the groups with and without intense FDG uptake (P < 0.05). Moreover, significant differences in ratios of distal spinal cord-to-cord background, to mediastinal blood pool, and to liver were observed between two groups (P < 0.05). Intense FDG uptake of distal cord was associated with age, diabetic status, and blood glucose level. Intense FDG uptake of distal spinal cord on total-body PET/CT may be physiological, more common in younger age, patients without diabetes, or lower fasting blood glucose.

Body Weight-Supported Treadmill Training Ameliorates Motoneuronal Hyperexcitability by Increasing GAD-65/67 and KCC2 Expression via TrkB Signaling in Rats with Incomplete Spinal Cord Injury

Spasticity is a typical consequence after spinal cord injury (SCI). The critical reasons are reducing the synthesis of Gamma-Aminobutyric Acid (GABA), glycine and potassium chloride co-transporter 2 (KCC2) inside the distal spinal cord. The current work aimed to test whether exercise training could increase the expression of glutamic acid decarboxylase 65/67 (GAD-65/67, the key enzymes in GABA synthesis) and KCC2 in the distal spinal cord via tropomyosin-related kinase B (TrkB) signaling. The experimental rats were randomly assigned to the following five groups: Sham, SCI/phosphate-buffered saline (PBS), SCI-treadmill training (TT)/PBS, SCI/TrkB-IgG, and SCI-TT/TrkB-IgG. After that, the model of T10 contusion SCI was used, then TrkB-IgG was used to prevent TrkB activity at 7 days post-SCI. Body weight-supported treadmill training started on the 8th day post-SCI for four weeks. The Hmax/Mmax ratio and the rate-dependent depression of H-reflex were used to assess the excitability of spinal motoneuronal networks. Western blotting and Immunohistochemistry techniques were utilized for measuring the expression of GAD-65, GAD-67, and KCC2. The findings revealed that exercise training could reduce motoneuronal excitability and boost GAD-65, GAD-67, and KCC2 production in the distal region of the spinal cord after SCI. The effects of exercise training were decreased after the TrkB signaling was inhibited. The present exploration demonstrated that exercise training increases GAD-65, GAD-67, and KCC2 expression in the spinal cord via TrkB signaling and that this method could also improve rats with motoneuronal hyperexcitability and spasticity induced by incomplete SCI.

Preterm Infant of Diabetic Mother with a Retrorectal Mass: A Troubling Tail Tale.

Preterm Infant of Diabetic Mother with a Retrorectal Mass: A Troubling Tail Tale.

Impact of general anaesthesia on parameters of bulbocavernosus reflex

Dysfunction of the pelvic organs in tumor lesions of the spinal cord is up to 20%. Registration of the bulbocavernosus reflex is performed to assess the integrity of the segmental apparatus of the spinal cord. Polymodal neurophysiological monitoring includes registration of the bulbocavernosus reflex during surgery of spinal cord tumors. The effect of the components of general anesthesia on the parameters of the bulbocavernosus reflex varies significantly according to various medical sources. The aim of the work was to compare the effect of inhalation anesthesia (sevoflurane) and total intravenous anesthesia (propofol) on the parameters of the bulbocavernosus reflex in the surgical treatment of spinal cord tumors. Thirty patients with intradural extramedullary and intramedullary tumors of the spinal cord at the level of Th11–S2 vertebrae were included in the study. The amplitude-frequency parameters of the bulbocavernosus reflex and the threshold intensity of stimulation were assessed in the study. The results of the study demonstrate that intraoperative registration of the bulbocavernosus reflex during resection of tumors of the distal spinal cord can be performed both with inhalation and total intravenous anesthesia. A sustained motor response of the bulbocavernosus reflex requires a higher intensity of stimulation with inhalation anesthesia with sevoflurane than with total intravenous anesthesia. If during the operation the depth of propofol's anesthesia increases by 1 mg/kg/h, then it is necessary to increase the current strength during stimulation by 10–11 mA.

Neural Stem Cells: Promoting Axonal Regeneration and Spinal Cord Connectivity.

Spinal cord injury (SCI) leads to irreversible functional impairment caused by neuronal loss and the disruption of neuronal connections across the injury site. While several experimental strategies have been used to minimize tissue damage and to enhance axonal growth and regeneration, the corticospinal projection, which is the most important voluntary motor system in humans, remains largely refractory to regenerative therapeutic interventions. To date, one of the most promising pre-clinical therapeutic strategies has been neural stem cell (NSC) therapy for SCI. Over the last decade we have found that host axons regenerate into spinal NSC grafts placed into sites of SCI. These regenerating axons form synapses with the graft, and the graft in turn extends very large numbers of new axons from the injury site over long distances into the distal spinal cord. Here we discuss the pathophysiology of SCI that makes the spinal cord refractory to spontaneous regeneration, the most recent findings of neural stem cell therapy for SCI, how it has impacted motor systems including the corticospinal tract and the implications for sensory feedback.

National Medical Research Center for Children’s Health

Abstract Introduction. Anorectal malformations are one of the most numerous groups of proctologic pathology in children. The incidence is 1 per 5,000 live births. Perineal ultrasound, distal colostography, and MRI of the pelvic organs and sacrococcygeal region are used to clarify the anatomico-topographic features of the malformation and identify concomitant malformations (presacral masses, distal spinal cord pathology). This article presents a clinical case of surgical treatment of an 11-year-old girl who underwent primary surgery for anorectal malformation with rectovestibular fistula in infancy. In the postoperative period for 10 years, the parents practically did not carry out rehabilitation therapy. These factors led to persistent decompensation of the lower intestine in the form of a giant megarectum, which required repeated anorectoplasty with resection of pathologically dilated parts of the intestinal tube. The article presents description of the repeated surgery with intraoperative electromyoidentification of the perineal muscles, data of follow-up 9 months after the repeated anorectoplasty with instrumental diagnostic methods (irrigography, functional study of the closing apparatus of the rectum).Discussion. This clinical observation illustrates complications following surgical treatment of anorectal malformation with rectovestibular fistula. Lack of intraoperative electromyoidentification of the muscles during primary anorectoplasty often resulted in ectopia of the neoanus relative to the center of the perineal muscle center. This circumstance was one of the causes of persistent chronic constipation in the postoperative period.Conclusion. The use of electromyostimulation during primary proctoplasty for reliable determination of the sphincter-levator complex topography is mandatory. Long sequential rehabilitation in the postoperative period including neoanus bougienage, provision of regular full defecation, physiotherapeutic treatment, as well as regular follow-up examination in the in-patient department is also an integral part of the treatment.

Caudal duplication syndrome: a literature review and reappraisal of its pathoembryogenesis.

The term caudal duplication syndrome (CDS) was first introduced for complex anomalies of the distal caudal end of the trunk. The pathoembryogenesis of CDS is yet unknown, although a few theories have been proposed. We reviewed the previously proposed pathoembryogenetic theories and suggested a new perspective through the common clinical characteristics shown in CDS cases reported in the literature. We conducted a systematic literature search of the online database PubMed from October 1993 to October 2020, using the search term "caudal duplication syndrome", according to the first mention of this entity. A total of 17 articles with 23 patients were reviewed. The most common manifestations were the duplication of the distal colon, genitourinary organs, and lower spine. Specifically, the duplicated bladders or uteri contacted their counterpart through a septum, and the duplicated bowels ran parallel. More caudal structures, such as the urethra or anus, were formed separately. The duplication seems to be a result of division by an intervening septum or structure in each part. In addition, duplication was not limited to the structures formed from the caudal cell mass (CCM), such as the distal spine and spinal cord, but also included hindgut structures. Moreover, anomalies involving caudal mesenchymal defects were also present. Considering clinical manifestations that are related to all three germ layers and seemingly the overseptation of these germ layers in CDS patients, with supporting data from animal experiments, events such as late-stage errors involving Hensen's node/the primitive streak and the duplication of the CCM with the hyperplasia of the abnormally located central caudal mesenchyme are probable pathoembryogenetic mechanisms for CDS. The "leakage" of the normal growth power of the caudal mesenchyme into the intervening midline space between the two CCMs and consequent weak lateral and caudal pushes of the caudal mesenchyme may explain the association of caudal agenesis or its related anomalies with CDS. We propose a theory that by a molecular interaction, an insult causes late gastrulation phase problems, resulting in ectopic primitive streak formation, and therefore, a duplication of the CCM is induced. Subsequently, the overactivity of abnormally positioned midline mesenchyme between the two CCMs may divide the hindgut derivatives by a central septum. Underactive lateral and caudal pushes of the caudal mesenchyme may lead to an association of features shown in caudal agenesis.

Effect of cerebrospinal fluid pressure elevation on spinal cord perfusion during aortic cross-clamping with distal aortic perfusion.

Distal aortic perfusion (DaP) is a widely accepted protective adjunct facilitating early reinstitution of visceral perfusion during extended thoracic and thoraco-abdominal aortic repair. DaP has also been suggested to secure distal inflow to the paraspinal collateral network via the hypogastric arteries and thereby reduce the risk of spinal cord ischaemia. However, an increase in cerebrospinal fluid (CSF) pressure is frequently observed during thoracoabdominal aortic aneurysm repair. The aim of this study was to evaluate the effects of DaP on regional spinal cord blood flow (SCBF) during descending aortic cross-clamping and iatrogenic elevation of cerebrospinal fluid pressure. Eight juvenile pigs underwent central cannulation for cardiopulmonary bypass according to our established experimental protocol followed by aortic cross-clamping of the descending thoracic and abdominal aorta-mimicking sequential aortic clamping-with the initiation of DaP. Thereafter, CSF pressure elevation was induced by the infusion of blood plasma until baseline CSF pressure was tripled. At each time-point, microspheres of different colours were injected allowing for regional SCBF analysis. DaP led to a pronounced hyperperfusion of the distal spinal cord [SCBF up to 480%, standard deviation (SD): 313%, compared to baseline]. However, DaP provided no or only limited additional flow to the upper and middle segments of the spinal cord (C1-Th7: 5% of baseline, SD: 5%; Th8-L2: 24%, SD: 39%), which was compensated by proximal flow only at C1-Th7 level. Furthermore, DaP could not counteract an experimental CSF pressure elevation, which led to a further decrease in regional SCBF most pronounced in the mid-thoracic spinal cord segment. Protective DaP during thoraco-abdominal aortic repair may be associated with inadequate spinal protection particularly at the mid-thoracic spinal cord level ('watershed area') and result in the adverse effect of a potentially dangerous hyperperfusion of the distal spinal cord segments.

Sudden Onset of Myelitis after COVID-19 Vaccination: An Under-Recognized Severe Rare Adverse Event

Myelitis has been reported as a complication of COVID-19 infection. However, it has rarely been reported as a complication of COVID-19 vaccination, and this may be the first case report following an mRNA vaccine. A 63 yo, otherwise healthy male, received his second dose of the Moderna vaccine on 08 April 2021. He had some initial pain and soreness at the injection site. Seventeen hours post dose, he reported pain and numbness in both calves which progressed to lower back pain, paresthesia in both feet, and pain in lower extremities. Over the day post- vaccination the patient’s condition worsened and he was unable to walk and unable to urinate voluntarily. On the second day post- vaccination he presented to the Emergency Department and was admitted to the University of Iowa hospital unable to walk with severe pain in lower back, legs and feet, and numbness in buttocks. Laboratory findings were unremarkable and lumbar puncture was not diagnostic. MRI revealed increased T2 cord signal seen in the distal spinal cord and conus. Initial treatment included IV Immunoglobulin for 2 days, followed by methylprednisolone 1000 mg/day IV for 5 days. Discharge from the hospital occurred on 16 April 2021 to inpatient rehabilitation. Treatment consisted of oral prednisone 60 mg/day with a tapering schedule. The patient slowly improved and was able to ambulate unassisted at 25 days post -vaccination. This case represents one of the first cases of myelitis reported in the literature after COVID-19 mRNA vaccination. As of 27 April 2021 the FDA VAERS system has 45 reports of transverse myelitis after COVID-19 vaccination (21 after Moderna vaccine, 19 were after Pfizer vaccine, and 5 occurred after Janssen vaccine).