The arterial blood supply of the human spinal cord

Clinical manifestations and magnetic resonance imaging features of spinal cord infarction

BACKGROUND AND OBJECTIVE

Spinal cord infarction (SCI) is a rare type of stroke, with no proposed classification or diagnostic criterium widely accepted and used in daily clinical practice currently. We try to explore the clinical manifestations and MRI features of SCI for improving the accurate diagnosis of SCI.

METHODS

Retrospectively analyzed the clinical data, MRI features, laboratory findings and outcomes of 40 patients who had been consecutively diagnosed with SCI in our hospital from June 2016 to January 2022.

RESULTS

Most of the SCI (92.5%) occurred at the level of T8-L2 and C4-T4. Transverse infarction (52.5%) and ASA territory infarction (27.5%) were the most common patterns. Longitudinally extensive lesions were noticed in 67.5% of the SCI and it might be a risk factor of poor prognosis (OR=21.11, 95%CI 2.14-208.29). Restricted diffusion of the SCI lesion occurred in 8h and a few lasted up to 60 days. All SCI showed spinal cord edema, accompanied by enhancement of the ventral cauda equina (13.8%), weakened enhancement of the dorsal venous plexus (44.8%), and vertebral infarction (25%). Most patients developed a stroke-like onset (92.5%) after movement (57.5%), with definite pain in the trunk or limbs (67.5%) and dissociative sensory disturbance (60.0%). The main etiologies of them include vascular abnormalities (45%) and iatrogenic injuries (15%).

CONCLUSION

An MRI classification of SCI based on the spinal cord blood supply was proposed. Restricted diffusion and co-existing abnormality of vertebral body and cauda equina may be the key neuroimaging feature for SCI diagnosis. Detailed history of vascular diseases or triggering factors are also helpful.

Association of Mean Upper Cervical Spinal Cord Cross-Sectional Area With Cerebral Small Vessel Disease: A Community-Based Cohort Study

BACKGROUND

The purpose of this study was to investigate the association between the mean upper cervical spinal cord cross-sectional area (MUCCA) and the risk and severity of cerebral small vessel disease (CSVD).

METHODS

Community-dwelling residents in Lishui City, China, from the cross-sectional survey in the PRECISE cohort study (Polyvascular Evaluation for Cognitive Impairment and Vascular Events) conducted from 2017 to 2019. We included 1644 of 3067 community-dwelling adults in the PRECISE study after excluding those with incorrect, incomplete, insufficient, or missing clinical or imaging data. Total and modified total CSVD scores, as well as magnetic resonance imaging features, including white matter hyperintensity, lacunes, cerebral microbleeds, enlarged perivascular spaces, and brain atrophy, were assessed at the baseline. The Spinal Cord Toolbox was used to measure the upper cervical spinal cord cross-sectional area of the C1 to C3 segments of the spinal cord and its average value was taken as MUCCA. Participants were divided into 4 groups according to quartiles of MUCCA. Associations were analyzed using linear regression models adjusted for age, sex, current smoking and drinking, medical history, intracranial volume, and total cortical volume.

RESULTS

The means±SD age of the participants was 61.4±6.5 years, and 635 of 1644 participants (38.6%) were men. The MUCCA was smaller in patients with CSVD than those without CSVD. Using the total CSVD score as a criterion, the MUCCA was 61.78±6.12 cm2 in 504 of 1644 participants with CSVD and 62.74±5.94 cm2 in 1140 of 1644 participants without CSVD. Using the modified total CSVD score, the MUCCA was 61.81±6.04 cm2 in 699 of 1644 participants with CSVD and 62.91±5.94 cm2 in 945 of 1644 without CSVD. There were statistical differences between the 2 groups after adjusting for covariates in 3 models. The MUCCA was negatively associated with the total and modified total CSVD scores (adjusted β value, -0.009 [95% CI, -0.01 to -0.003] and -0.007 [95% CI, -0.01 to -0.0006]) after adjustment for covariates. Furthermore, the MUCCA was negatively associated with the white matter hyperintensity burden (adjusted β value, -0.01 [95% CI, -0.02 to -0.003]), enlarged perivascular spaces in the basal ganglia (adjusted β value, -0.005 [95% CI, -0.009 to -0.001]), lacunes (adjusted β value, -0.004 [95% CI, -0.007 to -0.0007]), and brain atrophy (adjusted β value, -0.009 [95% CI, -0.01 to -0.004]).

CONCLUSIONS

The MUCCA and CSVD were correlated. Spinal cord atrophy may serve as an imaging marker for CSVD; thus, small vessel disease may involve the spinal cord in addition to being intracranial.

1. Lumbosacral radicular pain

INTRODUCTION

Patients suffering lumbosacral radicular pain report radiating pain in one or more lumbar or sacral dermatomes. In the general population, low back pain with leg pain extending below the knee has an annual prevalence that varies from 9.9% to 25%.

METHODS

The literature on the diagnosis and treatment of lumbosacral radicular pain was reviewed and summarized.

RESULTS

Although a patient's history, the pain distribution pattern, and clinical examination may yield a presumptive diagnosis of lumbosacral radicular pain, additional clinical tests may be required. Medical imaging studies can demonstrate or exclude specific underlying pathologies and identify nerve root irritation, while selective diagnostic nerve root blocks can be used to confirm the affected level(s). In subacute lumbosacral radicular pain, transforaminal corticosteroid administration provides short-term pain relief and improves mobility. In chronic lumbosacral radicular pain, pulsed radiofrequency (PRF) treatment adjacent to the spinal ganglion (DRG) can provide pain relief for a longer period in well-selected patients. In cases of refractory pain, epidural adhesiolysis and spinal cord stimulation can be considered in experienced centers.

CONCLUSIONS

The diagnosis of lumbosacral radicular pain is based on a combination of history, clinical examination, and additional investigations. Epidural steroids can be considered for subacute lumbosacral radicular pain. In chronic lumbosacral radicular pain, PRF adjacent to the DRG is recommended. SCS and epidural adhesiolysis can be considered for cases of refractory pain in specialized centers.

Epidural hematoma risks associated with ceasing vs maintaining anticoagulant and/or antiplatelet medications for cervical and thoracic interlaminar epidural steroid injections

Background

There is a lack of substantiated evidence to support or refute the risks of ceasing vs maintaining anticoagulant and/or antiplatelet medications (ACAP) prior to cervical and thoracic interlaminar epidural steroid injections. The ACAP medication is frequently stopped pre-procedure due to concerns for potential bleeding complications, particularly epidural hematomas (EH). This article provides evidence regarding EH incidence in this population.

Methods

Data for this study was collected retrospectively on all patients from September 19, 2009-Jun 16, 2017 who were scheduled for an Interlaminar Cervical and/or Thoracic Epidural Steroid Injections (IL-CTESI) and were on an ACAP medication at the time a procedure was scheduled. All possible adverse outcomes were then retrospectively analyzed via extensive data mining of the electronic medical record system with special emphasis on EHs.

Results

591 IL-CTESI were performed on patients taking ACAP medications. In total, 351 patients ceased their ACAP medication prior to the procedure and 240 maintained ACAP medication. Our findings demonstrate that there were no clinically relevant incidents of EHs in either cohort.

Conclusions

This data gives critical insight into the post-procedural EH risk for patients who had continued or stopped taking their ACAP medications prior to their IL-CTESI. The results from this study suggest re-evaluating the potential post-procedural EH risks associated with continuing vs ceasing these medications.

Anatomical study of arterial arrangement of the spinal cord in Syrian hamsters (Mesocricetus auratus)

This study aimed to investigate the arterial arrangement of the spinal cord in Syrian hamsters, and to identify differences and similarities to humans and experimental animals that are mostly used as models in studies into ischemic spinal cord injuries. This observational anatomical study was conducted on 20 adult Syrian hamsters using dissection and corrosion casting technique. The general anatomy of the arterial blood supply of spinal cord was obtained and noted as follows: (1) high variability in the level of the origin of right and left vertebral arteries, (2) the independent origin of dorsal intercostal arteries, (3) origin of lumbar arteries as a common trunk with right and left divisions, (4) presence of dorsal and ventral radicular branches in both sides of the cervical spinal cord with almost the same frequency, (5) greater presence of ventral and dorsal radicular branches in the left side of the thoracolumbar spinal cord, (6) two dorsal spinal arteries originating from the posterior inferior cerebellar arteries and extending to the caudal end of the thoracic spinal cord, (7) continuous ventral spinal artery originating from both vertebral arteries and extending to the conus medularis, and (8) presence of the artery of Adamkiewicz in the thoracic region of the spinal cord. From comparative anatomy viewpoints, the arteries supplying the spinal cord of Syrian hamsters exhibit many similarities with humans, laboratory rodents, and rabbits in many aspects compared to dogs, cats, and pigs. Overall, Syrian hamsters can be used as a proposed model in experimental studies of the spinal cord ischemia.

Variations in the origin of the anterior spinal artery in a Colombian population sample

Based on most neuroanatomical descriptions, the anterior spinal artery (ASA) originates from two small vessels of the vertebral arteries, which are anastomosed just before forming the basilar artery. This study aimed to determine and quantify the possible variants of the origin of the ASA and its trajectory in samples of human brain stems. Male brain stems with the superior portion of the spinal cord until myelomera C3 of 23 adult human, and no evident morphological alterations were selected. The brain stems were collected for three years and fixed in a 10% formalin solution at the Anatomy Laboratory of the Universidad de Caldas (Colombia). Five samples (21.7%) had variations in the origin and trajectory of the anterior spinal artery. The variations in the origin of the ASA could generate morphofunctional advantages instead of leading to complications. That is the case when there are two anterior spinal arteries since it would increase tissue perfusion, thus protecting part of the spinal cord from ischemic pathologies. It is essential to consider the variations that may exist in the supply of the anterior region of the spinal cord for clinical and surgical assessments due to variations in its supplied territory.

Development of the Arterial Supply of the Spinal Cord Tissue Based on Radioanatomical and Histological Studies in Cattle

PURPOSE

Angiographic techniques have gained increasing importance in suspected vascular disease of the spinal cord. This demands an advanced understanding of spinal cord blood vessel anatomy and its embryologically founded broad spectrum of variations. The aim of this study was to improve knowledge on contentious issues concerning the development of spinal cord arterial supply in higher mammals and to offer visual information of high didactic value.

METHODS

The prenatal development was examined in cattle, using multiplanar high-resolution microangiography of injected specimens and microscopic sections. The gestational ages of the 15 specimens were between the late embryonic and the early fetal period (5-11 weeks). Microangiography of the human spinal cord from an earlier published study were used to envisage an adult arterial vascularization pattern in higher mammals.

RESULTS

Establishment of the unpaired anterior spinal artery (ASA) goes through two procedures of reconfiguration until achieving its final design. Regression of the primarily established anteromedian tract is observed in cattle fetuses of 9-10 weeks. Return to the ontogenetic disposition of bilateral symmetry and a burst of vascularization from all parts of the spinal meninges follow and include the anterior median fissure as a preferred vascular pathway. Large sulcal/central arteries longitudinally anastomosing between each other emerge on both sides of the midline. The embryological pattern of exclusive peripheral medullary supply must have been converted into a combined system of predominant central (centrifugal) supply of the enlargements before a final unpaired ASA can be reconstructed.

CONCLUSION

Previous investigators focused on the early embryonic development of spinal cord arteries and missed the profound remodeling of the vascular architecture in the early fetal period.

High false-negative rate of the anterior spinal artery by intercostobronchial trunk arteriography alone compared to CT during arteriography

OBJECTIVES

This study aimed to assess the frequencies of the anterior spinal arteries identified by CT during arteriography (CTA) and arteriography alone.

METHODS

This retrospective study included 137 vessels in 83 patients who performed both bronchial arteriography and CTA and categorized them into three groups based on the catheter tip locations: intercostobronchial trunk (ICBT), bronchial artery (BA), and intercostal artery (ICA). The frequencies of anterior spinal artery identified by CTA and arteriography alone were compared for each group.

RESULTS

ICBT, BA, and ICA groups were evaluated by CTA in 46, 79, and 12 vessels, respectively. By CTA evaluation, anterior spinal artery was identified in seven vessels (15.2%) in ICBT group, 0 in BA group and two (16.7%) in ICA group. The frequencies of anterior spinal artery were significantly higher (p < 0.05) in ICBT and ICA groups than in BA group. By arteriography evaluation alone, a faint anterior spinal artery was identified in two vessels (4.3%) in ICBT group, 0 in BA group, and 1 (8.3%) in ICA group.

CONCLUSIONS

Anterior spinal artery branched only from the ICBT or ICA and not from the BA in both arteriography and CTA assessments. There was high false-negative rate (71%) of the anterior spinal artery by ICBT arteriography alone assessment compared to CTA assessment. This result explains one of the reasons that spinal ischemia occurs in arteriography-negative spinal artery cases.

ADVANCES IN KNOWLEDGE

False-negative rate of anterior spinal artery was 71% (5/7) by intercostobronchial trunk arteriography alone assessment.

Intermittent and Transient Hypotension-related Anterior Cord Syndrome following Elective Cervical Spine Surgery: A Case Report

Introduction:

Anterior cord syndrome (ACS) is a type of incomplete spinal cord injury caused by either direct compression of the anterior spinal cord, or by ischemia of the anterior spinal artery. This phenomenon has neither been described transiently nor intraoperatively.

Case Report:

We describe the case of a 61-year-old male who developed intermittent and transient anterior spinal cord syndrome secondary to hypotension related hypoperfusion of the anterior spinal artery after elective cervical spine surgery. Through close blood pressure monitoring and intensive care unit support, the patient regained full neurological recovery.

Conclusion:

Anterior spinal cord syndrome is a rare condition affecting the anterior 2/3 of the spinal cord, resulting in incomplete paralysis. Blood flow can be disrupted through the anterior spinal artery, either through thrombosis or hypotension. We describe our rare case so that surgeons may recognize this potentially devastating condition.

Cryptogenic cervical intramedullary abscess with rapidly progressive myelopathy: illustrative case

BACKGROUND

The purpose of the present case report is to highlight the presentation, workup, clinical decision making, and operative intervention for a 68-year-old woman who developed rapidly progressive myelopathy secondary to idiopathic cervical intramedullary abscess.

OBSERVATIONS

The patient underwent laminectomy and aspiration/biopsy of the lesion. Intraoperatively, division of the posterior median sulcus released a large volume of purulent material growing the oral pathogens Eikenella corrodens and Gemella morbillorum. Broad-spectrum antibiotics were initiated postoperatively. At the 6-month follow-up, the patient had almost completely recovered with some persistent hand dysesthesia. Complete infectious workup, including full dental assessment and an echocardiogram, failed to reveal the source of her infection.

LESSONS

The authors report the first case of cryptogenic spinal intramedullary abscess secondary to Eikenella spp. and Gemella spp. coinfection. Intramedullary abscesses are exceptionally rare and most commonly develop in children with dermal sinus malformations or in the context of immunosuppression. In adults without risk factors, they can readily be mistaken for more common pathologies in this age group, such as intramedullary neoplasms or demyelinating disease. Prompt diagnosis and management based on rapidly progressive myelopathy, assessment of infectious risk factors and/or symptoms, and targeted imaging are critical to avoid potentially devastating neurological sequelae.

Neurologic complications of diseases of the aorta

Neurologic complications of diseases of the aorta are common, as the brain and spinal cord function is highly dependent on the aorta and its branches for blood supply. Any disease impacting the aorta may have significant impact on the ability to deliver oxygenated blood to the central nervous system, resulting in ischemia-and if prolonged-cerebral and spinal infarct. The breadth of pathology affecting the aorta is diverse and neurologic complications can vary dramatically based on the location, severity, and underlying etiology. This chapter outlines the major pathology of the aorta while highlighting the associated neurologic complications. This chapter covers the entire spectrum of neurologic complications associated with aortic disease by beginning with a detailed overview of the spinal cord vascular anatomy followed by a discussion of the most common aortic pathologies affecting the nervous system, including aortic aneurysm, aortic dissection, aortic atherosclerosis, inflammatory and infectious aortopathies, congenital abnormalities, and aortic surgery.

Neurovascular anatomy: Spine

The arterial supply of the spinal cord is provided by the spinal branch of the cervical, thoracic, and lumbar intersegmental arteries. While supply is initially provided at each embryonic segment, only a few prominent anterior radiculomedullary arteries remain at the adult stage, including the arteries of the cervical and lumbosacral enlargements as well as a constant upper thoracic contributor. The spinal cord is surrounded by the vasocorona, an arterial network that includes several longitudinal anastomotic chains, notably the anterior and posterior spinal arteries, which respectively supply the central and peripheral components of the intrinsic vascularization. The intrinsic venous circulation is also divided into central and peripheral components. The perimedullary venous system includes several longitudinal anastomotic chains interconnected by the coronary plexus. The radiculomedullary veins loosely follow the spinal nerve roots on their way to the epidural plexus. Their point of passage through the thecal sac forms an important valve-like structure, the antireflux mechanism.

Anatomical study of the pial arterial network in human spinal cords

INTRODUCTION

Multiple collaterals originate from three main longitudinal vessels to perfuse the human spinal cord. Only a few classic studies published in the last century have investigated these collaterals. The current work proposes a possible classification of these vessels and analyzes their relative abundance along spinal cord segments.

MATERIALS AND METHODS

Human spinal cords (n = 30) from male and female cadavers were injected with colored latex through the vertebral, ascending cervical, costocervical trunk and segmental arteries and then fixed in formaldehyde solution. Afterwards, spinal vessels were dissected and the relative abundances of each type of collateral were quantified and compared between different spinal cord segments.

RESULTS

Collaterals of the anterior longitudinal pathway can be classified as central arteries and arteries for the anterior and lateral columns. Collaterals for the anterior column can be classified into two types: anteromedial and anterolateral. Arteries for the lateral column can be classified, according to their relationship with the dentate ligament, as either preligamentous or post-ligamentous. The collaterals of posterior longitudinal pathways can be divided between those for the posterior and those for the lateral column. In turn, the arteries for the posterior column can be classified into three types: median posterior, posteromedial and posterolateral. The collaterals for the lateral column were also classified as either pre- or post-ligamentous.

CONCLUSION

The relative abundance of the various types of collateral and anastomoses between longitudinal pathways was inhomogeneous along the spinal cord, with several statistically significant differences observed between spinal segments.

Analysis of spinal cord blood supply combining vascular corrosion casting and fluorescence microsphere technique: A feasibility study in an aortic surgical large animal model

INTRODUCTION

Spinal cord ischemia after cardiovascular interventions continues to be a devastating problem in modern surgery. The role of intraspinal vascular networks and anterior radiculomedullary arteries (ARMA) in preventing spinal cord ischemia is poorly understood.

MATERIALS AND METHODS

Landrace pigs (n = 30, 35.1 ± 3.9 kg) underwent a lateral thoracotomy. Fluorescent microspheres were injected into the left atrium and a reference sample was aspirated from the descending aorta. Repeated measurements of spinal cord and renal cortical blood flow from the left and right kidneys with three different microsphere colors in five pigs were taken to validate reproducibility. Spinal cord blood flow to the upper thoracic (T1-T4), mid-thoracic (T5-T8), lower thoracic (T9-T13), and lumbar (L1-L3) levels were determined. After euthanasia, we carried out selective vascular corrosion cast and counted the left and right ARMAs from levels T1-T13.

RESULTS

Blood flow analysis of the left and right kidneys revealed a strong correlation (r = .94, p < .001). We detected more left than right ARMAs, with the highest prevalence at T4 (p < .05). The mean number of ARMAs was 8 ± 2. Their number in the upper thoracic region ranged from 2 to 7 (mean of 5 ± 1), while in the lower thoracic region they ranged from 0 to 5 (mean of 3 ± 1 [p < .001]).

CONCLUSIONS

This study shows that combining fluorescence microsphere technique and vascular corrosion cast is well suited for assessing the blood flow and visualizing the arteries at the same time.

Anatomy of the Great Posterior Radiculomedullary Artery

BACKGROUND AND PURPOSE

Although considerable variability exists as to the overall caliber of radiculomedullary arteries, dominant radiculomedullary arteries such as the artery of Adamkiewicz exist. The existence of a great posterior radiculomedullary artery has attracted little attention and has been a matter of debate. The aim of this anatomic study was to determine the presence or absence of the great posterior radiculomedullary artery.

MATERIALS AND METHODS

We performed microsurgical dissection on formaldehyde-fixed cadaveric human spinal cords. The artery of Adamkiewicz in the spinal cord specimens (n = 50) was injected with colored latex until the small-caliber arterial vessels were filled and the great posterior radiculomedullary artery was identified. The course, diameter, and location of great posterior radiculomedullary artery were documented.

RESULTS

A great posterior radiculomedullary artery was identified in 36 (72%) spinal cord specimens. In 11 (22%) specimens, bilateral great posterior radiculomedullary arteries were present. In 13 cases (26%), a unilateral left-sided great posterior radiculomedullary artery was identified. In 11 cases (22%), a unilateral right-sided great posterior radiculomedullary artery was identified. In 1 specimen (2%), 3 right-sided great posterior radiculomedullary arteries were noted. The average size of the great posterior radiculomedullary arteries was 0.44 mm (range, 0.120-0.678 mm on the left and 0.260-0.635 mm on the right).

CONCLUSIONS

A great posterior radiculomedullary artery is present in most (72%) individuals. The authors describe the microsurgical anatomy of the great posterior radiculomedullary artery with emphasis on its morphometric parameters as well as its implications for spinal cord blood supply. Variations of the arterial supply to the dorsal cord are of great importance due to their implications for ischemic events, endovascular procedures, and surgical approaches.

Spinal ischaemia after thoracic endovascular aortic repair with left subclavian artery sacrifice: is there a critical stent graft length?

OBJECTIVES

Thoracic endovascular aortic repair (TEVAR) is used for treatment of thoracic aortic pathologies, but the covered stent graft can induce spinal ischaemia depending on the length used. The left subclavian artery contributes to spinal cord collateralization and is frequently occluded by the stent graft. Our objective was to investigate the impact of covered stent graft length on the risk of spinal ischaemia in the setting of left subclavian artery sacrifice.

METHODS

Twenty-six pigs (German country race, mean body weight 36 ± 4 kg) underwent simulated descending aortic TEVAR via left lateral thoracotomy, with left subclavian artery and thoracic segmental artery occlusion in normothermia. Animals were assigned to treatment groups according to simulated stent graft length: TEVAR to T8 (n = 4), TEVAR to T9 (n = 4), TEVAR to T10 (n = 4), TEVAR to T11 (n = 7) and TEVAR to T12 (n = 1) and a sham group (n = 6). End points included spinal cord perfusion pressure, cerebrospinal fluid pressure and spinal cord blood flow using fluorescent microspheres.

RESULTS

There were no group differences in spinal cord perfusion pressure drop or in spinal cord perfusion pressure regeneration potential at 3 h after the procedure: from a baseline average of 75 mmHg (95% confidence interval 71-83 mmHg) to 73 mmHg (67-75 mmHg) at 3 h in Group T10 versus from a baseline average of 67 mmHg (95% CI 50-81 mmHg) to 65 mmHg (95% confidence interval 48-81 mmHg) in Group T8. There were no differences in the spinal cord blood flow courses over time in the different groups nor was there any difference in cerebrospinal fluid pressure levels and cerebrospinal fluid pressure dynamics between groups. However, we did observe local blood flow distribution to the spinal cord that was inhomogeneous depending on the distance between the simulated stent graft end and the first thoracic anterior radiculomedullary artery.

CONCLUSIONS

The risk of spinal ischaemia after serial segmental artery occlusion does not depend on the distal extent of the aortic repair alone. Future attempts to allow patient risk stratification for spinal ischaemia need to focus on anterior radiculomedullary artery anatomy together with the extent of planned aortic repair.

A role for spinal cord hypoxia in neurodegeneration

The vascular system of the spinal cord is particularly complex and vulnerable. Damage to the main vessels or alterations to the regulation of blood flow will result in a reduction or temporary cessation of blood supply. The resulting tissue hypoxia may be brief: acute, or long lasting: chronic. Damage to the vascular system of the spinal cord will develop after a traumatic event or as a result of pathology. Traumatic events such as road traffic accidents, serious falls and surgical procedures, including aortic cross-clamping, will lead to an immediate cessation of perfusion, the result of which may not be evident for several days, but may have long-term consequences including neurodegeneration. Pathological events such as arterial sclerosis, venous occlusion and spinal cord compression will result in a progressive reduction of blood flow, leading to chronic hypoxia. While in some situations the initial pathology is exclusively vascular, recent research in neurodegenerative disease has drawn attention to concomitant vascular anomalies in disorders, including amyotrophic lateral sclerosis, spinal muscular atrophy and muscular sclerosis. Understanding the role of, and tissue response to, chronic hypoxia is particularly important in these cases, where inherent neural damage exacerbates the vulnerability of the nervous system to stressors including hypoxia.

Spinal Vascular Anatomy

This article reviews the arterial and venous anatomy of the spine and spinal cord. Special emphasis is placed on vessels critical to the conduct and interpretation of spinal angiography, notably the intersegmental artery and its cranial and caudal derivatives: the vertebral, supreme intercostal, and sacral arteries.

Functional Ultrasound Imaging of Spinal Cord Hemodynamic Responses to Epidural Electrical Stimulation: A Feasibility Study

This study presents the first implementation of functional ultrasound (fUS) imaging of the spinal cord to monitor local hemodynamic response to epidural electrical spinal cord stimulation (SCS) on two small and large animal models. SCS has been successfully applied to control chronic refractory pain and recently was evolved to alleviate motor impairment in Parkinson's disease and after spinal cord injury. At present, however, the mechanisms underlying SCS remain unclear, and current methods for monitoring SCS are limited in their capacity to provide the required sensitivity and spatiotemporal resolutions to evaluate functional changes in response to SCS. fUS is an emerging technology that has recently shown promising results in monitoring a variety of neural activities associated with the brain. Here we demonstrated the feasibility of performing fUS on two animal models during SCS. We showed in vivo spinal cord hemodynamic responses measured by fUS evoked by different SCS parameters. We also demonstrated that fUS has a higher sensitivity in monitoring spinal cord response than electromyography. The high spatial and temporal resolutions of fUS were demonstrated by localized measurements of hemodynamic responses at different spinal cord segments, and by reliable tracking of spinal cord responses to patterned electrical stimulations, respectively. Finally, we proposed optimized fUS imaging and post-processing methods for spinal cord. These results support feasibility of fUS imaging of the spinal cord and could pave the way for future systematic studies to investigate spinal cord functional organization and the mechanisms of spinal cord neuromodulation in vivo.

An Interventionalist's Guide to Hemoptysis in Cystic Fibrosis

Massive hemoptysis occurs in a minority of patients with cystic fibrosis, with an annual incidence of 1%. Although rare, massive hemoptysis can be a severe and potentially fatal complication of this disease. Beyond the acute life-threatening event, hemoptysis in patients with cystic fibrosis has been associated with faster decline in lung function, accelerated need for lung transplant, and increased mortality. The bronchial arteries are the culprit vessels in over 90% of cases of hemoptysis. This normally quiescent vascular system undergoes remarkable hypertrophy, collateralization, and angiogenesis before the onset of hemoptysis, introducing numerous pitfalls for the interventionalist. However, in experienced hands, bronchial artery embolization is a safe and potentially lifesaving therapy. Preprocedural noninvasive imaging, specifically computed tomographic angiography, has been repeatedly validated for helping to localize the likely site of bleeding, characterizing pertinent arterial anatomy, and promoting efficient and effective intervention; it has been recommended for all stable patients with hemoptysis. Success in the angiographic suite requires a thorough understanding of normal and variant bronchial arterial anatomy, appropriate patient selection, and a meticulous embolization technique. A meticulous approach to imaging and intervention, conscientious of both visualized and nonvisualized collateral pathways and nontarget vessels, can minimize potentially devastating complications. This review summarizes the current literature, modern procedural techniques, and emerging controversies, serving to guide an evolving approach to management of patients with cystic fibrosis and hemoptysis. ^©RSNA, 2018.

Spinal cord

We first present a brief historic review of developments in the understanding of spinal cord clinical neuroanatomy and neurophysiology over the past 200 years. We then discuss the technical aspects that apply to the examination of the human spinal cord giving details on the interrelations between the spinal cord and the overlying structures, including the meninges and vertebrae. The subsequent discussion focuses on diseases of the spinal cord. Diseases that affect the spinal cord are vascular disease, diseases of spinal column, trauma, developmental abnormalities, central nervous system degenerative disease, inflammatory disease, metabolic and nutritional myelopathies, and tumors. We summarize our knowledge regarding general reactions of spinal cord tissue to disease, in particular Wallerian degeneration of descending/ascending tracts and axonal reaction. Two categories of disease will be covered in depth: vascular disease of the spinal cord, including a review of normal vascular anatomy, and diseases of the vertebral column that can affect the cord secondarily.

Spinal cord infarction in a sick neonate from predominant haemorrhagic aetiology: a case report

INTRODUCTION

Spinal cord injuries in new born infants following a traumatic delivery or umbilical cord catheterisation due to thromboembolism are well known. Cases with atraumatic acute onset of neonatal paraplegia have also been described in preterm babies or babies born small for gestational age with a stormy postnatal course related to ischaemic aetiology. We describe a rare case of infarction of the spinal cord from a predominant haemorrhagic aetiology.

CASE PRESENTATION

A term female baby, first child of unrelated parents, was born by normal vaginal delivery. She had meconium aspiration at birth, leading to severe respiratory distress, requiring neonatal intensive care admission. At 2 weeks, she developed new flaccid paraplegia. MRI scan of the spine showed haemorrhagic infarction of the spinal cord from the level of thoracic inlet, vertebral level C7-T1. A follow-up MRI scan at 11 months revealed severe atrophy of the cord distal to C6. At 3 years of age, she had good upper-limb function, diaphragmatic breathing and flaccid paralysis of lower limbs.

DISCUSSION

In an acutely unwell term infant with symptoms of paralysis or spinal cord damage, haemorrhagic infarction needs to be considered in the differential diagnosis. To our knowledge, this is the first reported case of spinal cord injury in a term infant with a haemorrhagic lesion, and it helps to understand the pathogenesis of nontraumatic insult.

Fiber-optic Monitoring of Spinal Cord Hemodynamics in Experimental Aortic Occlusion

BACKGROUND

Spinal cord ischemia occurs frequently during thoracic aneurysm repair. Current methods based on electrophysiology techniques to detect ischemia are indirect, non-specific, and temporally slow. In this article, the authors report the testing of a spinal cord blood flow and oxygenation monitor, based on diffuse correlation and optical spectroscopies, during aortic occlusion in a sheep model.

METHODS

Testing was carried out in 16 Dorset sheep. Sensitivity in detecting spinal cord blood flow and oxygenation changes during aortic occlusion, pharmacologically induced hypotension and hypertension, and physiologically induced hypoxia/hypercarbia was assessed. Accuracy of the diffuse correlation spectroscopy measurements was determined via comparison with microsphere blood flow measurements. Precision was assessed through repeated measurements in response to pharmacologic interventions.

RESULTS

The fiber-optic probe can be placed percutaneously and is capable of continuously measuring spinal cord blood flow and oxygenation preoperatively, intraoperatively, and postoperatively. The device is sensitive to spinal cord blood flow and oxygenation changes associated with aortic occlusion, immediately detecting a decrease in blood flow (-65 ± 32%; n = 32) and blood oxygenation (-17 ± 13%, n = 11) in 100% of trials. Comparison of spinal cord blood flow measurements by the device with microsphere measurements led to a correlation of R = 0.49, P < 0.01, and the within-sheep coefficient of variation was 9.69%. Finally, diffuse correlation spectroscopy is temporally more sensitive to ischemic interventions than motor-evoked potentials.

CONCLUSION

The first-generation spinal fiber-optic monitoring device offers a novel and potentially important step forward in the monitoring of spinal cord ischemia.

Spinal Cord Blood Supply and Its Surgical Implications

The blood supply to the spine is based on a predictable segmental vascular structure at each spinal level, but true radiculomedullary arteries, which feed the dominant cord supply vessel, the anterior spinal artery, are relatively few and their locations variable. Under pathologic conditions, such as aortic stent grafting, spinal deformity surgery, or spinal tumor resection, sacrifice of a dominant radiculomedullary vessel may or may not lead to spinal cord ischemia, depending on dynamic autoregulatory or collateral mechanisms to compensate for its loss. Elucidation of the exact mechanisms for this compensation requires further study but will be aided by preoperative, intraoperative, and postoperative comparative angiography. Protocols in place at our center and others minimize the risk of spinal cord ischemia during planned radiculomedullary vessel sacrifice.

Focal compression of the upper left thoracic intersegmental arteries as a potential cause of spinal cord ischemia

BACKGROUND AND PURPOSE

This study was prompted by recurrent angiographic observations of focal stenoses involving the proximal segment of the left upper thoracic intersegmental arteries, a few centimeters distal to their origin. The purpose was to investigate the nature and prevalence of this anomaly.

MATERIALS AND METHODS

The existence of non-ostial thoracic intersegmental artery stenoses was evaluated in 50 angiograms; the contribution of stenosed branches to the anterior spinal artery was recorded. Angiograms performed in 3 patients with right-sided aortas were also reviewed. The topographic relationships of the upper thoracic intersegmental artery with surrounding structures were investigated in 3 cadavers.

RESULTS

Thirty-seven non-ostial stenoses were found in 26 patients (52%), predominantly on the left side (92%), between T3 and T8, most frequently at T4 and T5 (54%). Severe lesions were observed in 10% of cases. Patients with stenoses had fewer detectable anterior radiculomedullary arteries between T3 and T5 (35% versus 54%). Upper intersegmental artery stenoses, documented on the left side of all 3 specimens, appeared to be caused by the recurrent path of these intersegmental arteries related to the leftward position of the thoracic aorta, and by their course around reinforced paramedian longitudinal strands of the endothoracic fascia.

CONCLUSIONS

Upper thoracic intersegmental artery stenoses are frequent. They result from the leftward deviation of the descending aorta and the existence of a fixed point along the course of the intersegmental arteries related to the endothoracic fascia. Because contributors to the spinal vascularization often originate at similar levels, these stenoses may play a role in the susceptibility of the upper and midthoracic spinal cord to ischemia.

The Artery of von Haller

BACKGROUND:

Although recognized since the 18th century, radiculomedullary arteries (RMAs) originating from upper thoracic intersegmental arteries are generally considered to be inconstant branches of little clinical importance. Yet, such vessels are commonly observed during spinal angiography.

OBJECTIVE:

To evaluate the angiographic prevalence of upper thoracic RMAs, in particular, branches supplying the anterior spinal artery (ASA).

METHODS:

Fifty spinal angiograms were reviewed. Anterior and posterior RMAs originating in the upper thoracic region (T3 to T7) were recorded. The level of origin of the artery of Adamkiewicz (T8 to L3) was also noted.

RESULTS:

Forty-three patients (86%) had at least 1 ASA contributor between T3 and T7. Of the other 7 patients, 4 had one at an immediately adjacent level (T2 or T8). The most frequent origin of upper thoracic anterior RMAs was left T5 (n = 10). Only left T9 (n = 12) and left T8 (n = 11) were more common. When combining the left and right sides, an ASA contributor was more frequent at T5 (n = 16) than at any other level (n = 15 for T9, n = 14 for T8). The sum of ASA contributors at T4 and T5 (n = 27) represented 54% of all upper thoracic anterior RMAs, and 23% of all anterior RMAs between T3 and L3.

CONCLUSION:

A significant upper thoracic anterior RMA distinct from the artery of Adamkiewicz appears to be a constant anatomic feature, which undermines the classic concept of an arterial watershed zone in the thoracic region. We propose to name this artery after Albrecht von Haller, who documented its existence in 1754.

Vascular diseases of the spinal cord

Vascular disease affecting the spinal can cause substantial neurologic morbidity. Several vascular spinal cord ailments present as neurologic emergencies, and should thus be recognizable to the practicing neurologist. We review the epidemiology, presentation, management strategies, and prognosis of various pathologies, including infarction, dural arteriovenous fistula, arteriovenous malformation, cavernous malformation, compressive epidural hematoma, vasculitis, and genetic abnormalities.

Cerebrospinal fluid drainage for thoracic and thoracoabdominal aortic aneurysm surgery

BACKGROUND

During aortic aneurysm surgery, cross-clamping can lead to inadequate blood supply to the spinal cord resulting in neurological deficit. Cerebrospinal fluid drainage (CSFD) may increase the perfusion pressure to the spinal cord and hence reduce the risk of ischaemic spinal cord injury.

OBJECTIVES

To determine the effect of CSFD during thoracic and thoracoabdominal aortic aneurysm (TAAA) surgery on the risk of developing spinal cord injury.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched May 31 2012) and CENTRAL (2012, Issue 5) for publications describing randomised controlled trials of cerebrospinal fluid drainage for thoracic and thoracoabdominal aortic aneurysm surgery. Reference lists of relevant articles were checked.

SELECTION CRITERIA

Randomised trials involving CSFD during thoracic and TAAA surgery.

DATA COLLECTION AND ANALYSIS

Both authors assessed the quality of trials independently. SNK extracted data and GS verified the data.

MAIN RESULTS

Three trials with a total of 287 participants operated on for Type I or II TAAA were included.In the first trial of 98 participants, neurological deficits in the lower extremities occurred in 14 (30%) of CSFD group and 17 (33%) controls. The deficit was observed within 24 hours of the operation in 21 (68%), and from three to 22 days in 10 (32%) participants. CSFD did not have a significant benefit in preventing ischaemic injury to the spinal cord.The second trial of 33 participants used a combination of CSFD and intrathecal papaverine. It showed a statistically significant reduction in the rate of postoperative neurological deficit (P = 0.039), compared to controls. Analysis was undertaken after only one third of the estimated sample size had entered the trial.In the third trial TAAA repair was performed on 145 participants. CSFD was initiated during the operation and continued for 48 hours after surgery. Paraplegia or paraparesis occurred in 9 of 74 participants (12.2%) in the control group versus 2 of 82 participants (2.7%) receiving CSFD (P = 0.03). Overall, CSFD resulted in an 80% reduction in the relative risk of postoperative deficits. Meta-analysis showed an odds ratio (OR) of 0.48 (95 % confidence interval (CI) 0.25 to 0.92). For CSFD-only trials, OR was 0.57 (95% CI 0.28 to 1.17) and for intention-to-treat analysis in CSFD-only studies, the OR remained unchanged.

AUTHORS' CONCLUSIONS

There are limited data supporting the role of CSFD in thoracic and thoracoabdominal aneurysm surgery for prevention of neurological injury. Further clinical and experimental studies are indicated.

Spinal cord injury after conducting transcatheter arterial chemoembolization for costal metastasis of hepatocellular carcinoma

Transcatheter arterial chemoembolization (TACE) has been used widely to treat patients with unresectable hepatocellular carcinoma. However, this method can induce various adverse events caused by necrosis of the tumor itself or damage to nontumor tissues. In particular, neurologic side effects such as cerebral infarction and paraplegia, although rare, may cause severe sequelae and permanent disability. Detailed information regarding the treatment process and prognosis associated with this procedure is not yet available. We experienced a case of paraplegia that occurred after conducting TACE through the intercostal artery to treat hepatocellular carcinoma that had metastasized to the rib. In this case, TACE was attempted to relieve severe bone pain, which had persisted even after palliative radiotherapy. A sudden impairment of sensory and motor functions after TACE developed in the trunk below the level of the sternum and in both lower extremities. The patient subsequently received steroid pulse therapy along with supportive care and continuous rehabilitation. At the time of discharge the patient had recovered sufficiently to enable him to walk by himself, although some paresthesia and spasticity remained.

Blood supply and vascular reactivity of the spinal cord under normal and pathological conditions

The authors present a review of spinal cord blood supply, discussing the anatomy of the vascular system and physiological aspects of blood flow regulation in normal and injured spinal cords. Unique anatomical functional properties of vessels and blood supply determine the susceptibility of the spinal cord to damage, especially ischemia. Spinal cord injury (SCI), for example, complicating thoracoabdominal aortic aneurysm repair is associated with ischemic trauma. The rate of this devastating complication has been decreased significantly by instituting physiological methods of protection. Traumatic SCI causes complex changes in spinal cord blood flow, which are closely related to the severity of injury. Manipulating physiological parameters such as mean arterial blood pressure and intrathecal pressure may be beneficial for patients with an SCI. Studying the physiopathological processes of the spinal cord under vascular compromise remains challenging because of its central role in almost all of the body's hemodynamic and neurofunctional processes.