Advances in imaging of the spinal cord vascular supply and its relationship with paraplegia after aortic interventions. A review

Preoperative Spinal Arterial Supply Mapping Using Non-Selective Cone Beam Computed Tomography before Complex Aortic Repair

Pre-op spinal arterial mapping is crucial for complex aortic repair. This study explores the utility of non-selective cone beam computed tomography (CBCT) for pre-operative spinal arterial mapping to identify the Adamkiewicz artery (AKA) in patients undergoing open or endovascular repair of the descending thoracic or thoracoabdominal aorta at risk of spinal cord ischemia. Pre-operative non-selective dual-phase CBCT after intra-aortic contrast injection was performed in the aortic segment to be treated. The origin of detected AKA was assessed based on image fusion between CBCT and pre-interventional computed tomography angiography. Then, the CBCT findings were compared with the incidence of postoperative spinal cord ischemia (SCI). Among 21 included patients (median age: 68 years, 20 men), AKA was detected in 67% within the explored field of view, predominantly from T7 to L1 intercostal and lumbar arteries. SCI occurred in 14%, but none when AKA was not detected (p < 0.01). Non-selective CBCT for AKA mapping is deemed safe and feasible, with potential predictive value for post-surgical spinal cord ischemia risk. The study concludes that non-selective aortic CBCT is a safe and feasible method for spinal arterial mapping, providing promising insights into predicting post-surgical SCI risk.

Supraneural versus Infraneural Approach to transforaMinal Epidural StEroid injection for unilateral lumbosacral radicular pain (SIAMESE): a study protocol for a randomised non-inferiority trial

Background

Lumbosacral radicular pain is commonly treated by transforaminal steroid epidural injection. There are two methods: the supraneural and the infraneural approaches. The supraneural approach can result in rare but catastrophic consequences from injury to the radiculomedullary artery. The infraneural technique avoids the artery; both approaches show efficacy and are used locally.

Methods

This is a protocol for a randomised, single-blinded, non-inferiority trial of infraneural vs supraneural transforaminal epidural injection for lumbosacral radicular pain at a tertiary referral pain management clinic. Adult patients (n=92) with moderate-to-severe lumbosacral radicular pain of >3 months duration, scheduled for transforaminal epidural steroid injection, will be randomised to epidural by either the infraneural or supraneural approach. Only the treating physicians will know which route is used. The primary outcome measure is the differential impact on pain intensity score at 3 months. Secondary outcome measures will include disability and function scores, sleep and activity measures, and adverse events. Participants will be followed up for 12 months.

Conclusions

This study will determine whether the techniques are comparable and, if so, will enable recommendations for the use of an approach without risk of artery damage and catastrophic injury.

Clinical trial registration

ISRCTN 36195887.

Towards rapid intraoperative axial localization of spinal cord ischemia with epidural diffuse correlation monitoring

Spinal cord ischemia leads to iatrogenic injury in multiple surgical fields, and the ability to immediately identify onset and anatomic origin of ischemia is critical to its management. Current clinical monitoring, however, does not directly measure spinal cord blood flow, resulting in poor sensitivity/specificity, delayed alerts, and delayed intervention. We have developed an epidural device employing diffuse correlation spectroscopy (DCS) to monitor spinal cord ischemia continuously at multiple positions. We investigate the ability of this device to localize spinal cord ischemia in a porcine model and validate DCS versus Laser Doppler Flowmetry (LDF). Specifically, we demonstrate continuous (>0.1Hz) spatially resolved (3 locations) monitoring of spinal cord blood flow in a purely ischemic model with an epidural DCS probe. Changes in blood flow measured by DCS and LDF were highly correlated (r = 0.83). Spinal cord blood flow measured by DCS caudal to aortic occlusion decreased 62%. This monitor demonstrated a sensitivity of 0.87 and specificity of 0.91 for detection of a 25% decrease in flow. This technology may enable early identification and critically important localization of spinal cord ischemia.

Paraplegia after transforaminal epidural steroid injection in a patient with severe lumbar disc herniation - A case report

Background

Transforaminal epidural steroid injection (TFESI) is a conservative treatment for patients with lumbar disc herniation (LDH). However, there are reports of various complications that can occur after TFESI; among these, paraplegia is a serious complication.

Case

A 70-year-old woman who was unable to lie supine due to low back pain exacerbation during back extension underwent TFESI. After injection, there was pain relief and the patient was able to lie supine; however, paraplegia developed immediately. Magnetic resonance imaging confirmed cauda equina syndrome (CES) due to nerve compression from L1–2 LDH. We determined that the patient's LDH was already severe enough to be considered CES and that the TFESI procedure performed without an accurate understanding of the patient's condition aggravated the disease.

Conclusions

It is important to accurately determine the cause of pain and disease state of a patient to establish a correct treatment plan before TFESI is performed.

Extravascular risk factors in the prognostic evaluation for spinal cord injury during thoraco-abdominal aortic aneurysm exclusion: a case report

Background

The etiology of delayed-onset spinal cord injury (SCI) following endovascular repair of thoraco-abdominal aortic aneurysms (TAAA) is still unclear and may be related to multiple factors. Extravascular factors, such as lumbar spinal stenosis (LSS), may play a significant role in the selection of patient at risk of SCI. In this report we describe a case of paraplegia following thoracic endovascular aortic repair (TEVAR) in a patient suffering from severe and symptomatic LSS and undergoing staged endovascular repair of a TAAA.

Case presentation

A 70-year-old man was admitted to our department with an asymptomatic type III TAAA in previous open repair for abdominal aortic aneurysm. The patient complained of buttock and thigh claudication in the absence of defects in the pelvic perfusion; a spinal magnetic resonance angiography (MRA) showed a severe narrowing of the lumbar canal.. After 24 h from first-step procedure (TEVAR) paraplegia was detected. A cerebrospinal fluid (CSF) drainage was then placed with incomplete recovery.

Conclusions

Stenotic damage to the spinal cord is thought to be the result of direct compression of the neural elements and ischemic disruption of arterial and venous structures surrounding the spinal cord. This comorbidity may constitute an additional anatomic risk factor in those patients currently recognized as prognostically associated to the development of SCI.

Use of Fenestrated Stent-Grafts for Preservation of Spinal Artery Flow During Endovascular Repair of Thoracoabdominal Aortic Disease

We illustrate the safety and feasibility of the application of fenestrated stent-grafts for the preservation of spinal artery flow during endovascular repair of thoracoabdominal aortic aneurysms (TAAA) in 2 patients deemed high-risk for spinal cord ischemia (SCI). In one case, an unstented fenestration was used in a 78-year-old male treated for distal stent-graft induced new entry tear. In the other case, a fenestration with a bridging stent-graft was used to revascularize a spinal artery in a 66-year-old female with Marfan disease and island patch aneurysm following open TAAA reconstruction. Both procedures were successful without any postoperative neurologic complication. The unstented fenestration led to a type III endoleak that required the relining of the aortic stent-graft 2 years later. The stented spinal fenestration was patent at a 5-year imaging follow-up.

3D Digital Anatomic Angioarchitecture of the Rat Spinal Cord: A Synchrotron Radiation Micro-CT Study

Comprehensive analysis of 3D angioarchitecture within the intact rat spinal cord remains technically challenging due to its sophisticated anatomical properties. In this study, we aim to present a framework for ultrahigh-resolution digitalized mapping of the normal rat spinal cord angioarchitecture and to determine the physiological parameters using synchrotron radiation micro-CT (SRμCT). Male SD rats were used in this ex vivo study. After a proportional mixture of contrast agents perfusion, the intact spinal cord covered the cervical spinal from the upper of the 1st cervical vertebra to the 5th lumbar vertebra was harvested and cut into proper lengths within three distinct regions: Cervical 3–5 levels, Thoracic 10–12 levels, Lumbar 3–5 levels spinal cord and examined using SRμCT. This method enabled the replication of the complicated microvasculature network of the normal rat spinal cord at the ultrahigh-resolution level, allowing for the precise quantitative analysis of the vascular morphological difference among cervical, thoracic and lumbar spinal cord in a 3D manner. Apart from a series of delicate 3D digital anatomical maps of the rat spinal cord angioarchitecture ranging from the cervical and thoracic to the lumbar spinal cord were presented, the 3D reconstruction data of SRμCT made the 3D printing of the spinal cord targeted selected microvasculature reality, that possibly provided deep insight into the nature and role of spinal cord intricate angioarchitecture. Our data proposed a new approach to outline systematic visual and quantitative evaluations on the 3D arrangement of the entire hierarchical microvasculature of the normal rat spinal cord at ultrahigh resolution. The technique may have great potential and become useful for future research on the poorly understood nature and function of the neurovascular interaction, particularly to investigate their pathology changes in various models of neurovascular disease.

SRμCT Reveals 3D Microstructural Alterations of the Vascular and Neuronal Network in a Rat Model of Chronic Compressive Thoracic Spinal Cord Injury

The complex pathology of chronic thoracic spinal cord compression involves vascular and neuroarchitectural repair processes that are still largely unknown. In this study, we used synchrotron radiation microtomography (SRμCT) to quantitatively characterize the 3D temporal-spatial changes in the vascular and neuronal network after chronic thoracic spinal cord compression in order to obtain further insights into the pathogenesis of this disease and to elucidate its underlying mechanisms. Direct 3D characterization of the spinal cord microvasculature and neural microstructure of the thoracic spinal cord was successfully reconstructed. The significant reduction in vasculature and degeneration of neurons in the thoracic spinal cord visualized via SRμCT after chronic compression were consistent with the changes detected by immunofluorescence staining. The 3D morphological measurements revealed significant reductions of neurovascular parameters in the thoracic spinal cord after 1 month of compression and became even worse after 6 months without relief of compression. In addition, the distinct 3D morphological twist and the decrease in branches of the central sulcal artery after chronic compression vividly displayed that these could be the potential triggers leading to blood flow reduction and neural deficits of the thoracic spinal cord. Our findings propose a novel methodology for the 3D analysis of neurovascular repair in chronic spinal cord compression, both qualitatively and quantitatively. The results indicated that compression simultaneously caused vascular dysfunction and neuronal network impairment, which should be acknowledged as concurrent events after chronic thoracic spinal cord injury. Combining neuroprotection with vasoprotection may provide promising therapeutic targets for chronic thoracic spinal cord compression.

Spinal subarachnoid hemorrhage in type B aortic dissection: a rare presentation

Paraplegia is a common complication encountered during surgical and endovascular repair of aortic diseases. At times, it is also a presenting feature of aortic dissection. Involvement of more than one spinal blood supply system is the most common cause of spinal cord ischemia. Proper planning is needed to prevent and treat spinal cord ischemia. We report this rare case of acute type B aortic dissection that presented with paraplegia due to a spinal subarachnoid hemorrhage.

Spinal epidural hematoma occurring at a distance from the transforaminal epidural injection site: A case report

RATIONALE

Transforaminal epidural steroid injection (TFESI) is a conservative method to treat back pain due to radiculopathy. However, epidural hematoma can occur after the procedure by various mechanisms, which can cause serious complications.

PATIENT CONCERNS

An 82-year-old man with spinal stenosis was treated with TFESI in the right intervertebral foramen at the L2-L3 level. The next morning, he experienced severe back pain and diffuse motor deficit.

DIAGNOSIS

Emergency magnetic resonance imaging revealed fluid collection in the posterior epidural space at the T11-L1 level with central-canal stenosis.

INTERVENTIONS

Emergency hematoma evacuation was performed to remove the epidural hematoma.

OUTCOMES

After the surgery, the back pain disappeared.

LESSONS

Epidural hematoma may occur due to causes other than direct needle injury after TFESI. Therefore, careful observation of the patient is necessary after the procedure.

Advantages of 70-kV CT Angiography for the Visualization of the Adamkiewicz Artery: Comparison with 120-kV Imaging

BACKGROUND AND PURPOSE

Preprocedural identification of the Adamkiewicz artery is crucial in patients with aortic diseases. This study aimed to compare 70-kV CTA with conventional 120-kV CTA for the identification of the Adamkiewicz artery, examining differences in radiation dose and image quality.

MATERIALS AND METHODS

We retrospectively analyzed 2 equal groups of 60 patients who had undergone 70-kV or 120-kV CTA to detect the Adamkiewicz artery before aortic repair. Size-specific dose estimate, the CT number of the aorta, and the contrast-to-noise ratio of the anterior spinal artery to the spinal cord were recorded. Furthermore, detectability of the Adamkiewicz artery was evaluated by using a 4-point continuity score (3, definite to 0, undetectable).

RESULTS

There was significantly lower radiation exposure with 70-kV CTA than 120-kV CTA (median size-specific dose estimate, 23.1 versus 61.3 mGy, respectively; P < .001). CT number and contrast-to-noise ratio were both significantly higher in the 70-kV CTA group than the 120-kV group (999.1 HU compared with 508.7 HU, and 5.6 compared with 3.4, respectively; P < .001 for both). Detectability of the Adamkiewicz artery was not impaired in the 70-kV CTA group (90.0% versus 83.3% in the 120-kV group, P = .28). Moreover, the Adamkiewicz artery was detected with greater confidence with 70-kV CTA, reflected by a significantly superior continuity score (median, 3) compared with 120-kV CTA (median, 2; P = .001).

CONCLUSIONS

Seventy-kilovolt CTA has substantial advantages for the identification of the Adamkiewicz artery before aortic repair, with a significantly lower radiation exposure and superior image quality than 120-kV CTA.

Development of Collaterals to the Spinal Cord after Endovascular Stent Graft Repair of Thoracic Aneurysms

OBJECTIVES

In thoracic and thoraco-abdominal aortic aneurysm repair, spinal cord injury (SCI) is devastating. Detection of the Adamkiewicz artery might be important for preventing SCI. Although thoracic endovascular stent grafts often occlude the segmental artery, the incidence of SCI in thoracic endovascular aortic repair is thought to be low compared with open repair. This study aimed to evaluate how the Adamkiewicz artery is supplied after segmental arteries are occluded by stent grafts.

METHODS

From March 2007 to August 2015, 32 patients were enrolled whose segmental arteries that were connected to the Adamkiewicz arteries were occluded by stent grafts. Segmental arteries, Adamkiewicz arteries, collateral circulation into the Adamkiewicz arteries, and anterior spinal arteries were pre- and post-operatively evaluated by computed tomography angiography.

RESULTS

Post-operatively, Adamkiewicz arteries were detected in 24 (75%) patients, except for two patients with paraplegia and six without paraplegia. Post-operative Adamkiewicz arteries were the same as pre-operative Adamkiewicz arteries, except for one Adamkiewicz artery that was located at two vertebral levels below the pre-operative level. SCI occurred in two (6.3%) patients. The distribution of feeding arteries into the Adamkiewicz artery post-operatively was divided into three patterns as follows: a segmental artery below the distal landing zone of the stent graft (53%), branches of the left subclavian artery (33%), and a branch of the left external iliac artery (13%).

CONCLUSIONS

The length of the stent graft should be as short as possible. Blood supply to the left subclavian artery should be maintained because segmental arteries below the segmental artery occluded by the stent graft and branches of the left subclavian artery can become collaterals post-operatively.

Anatomia da circulação medular

ResumoA intrincada anatomia tridimensional da irrigação medular é frequentemente explanada na literatura com diferentes nomenclaturas e devido a sua alta relevância no estudo da isquemia medular, o estudo da terminologia se faz necessário para melhor compreensão do tema. A artéria de Adamkiewicz, também chamada de artéria radicular magna, é a via principal. Foi realizada a revisão da literatura com equiparação das nomenclaturas utilizadas e elaboração de descrição acurada e sumarizada do conhecimento atual sobre a vascularização medular.

Ginsenoside Rd attenuates mitochondrial permeability transition and cytochrome C release in isolated spinal cord mitochondria: involvement of kinase-mediated pathways

Ginsenoside Rd (Rd), one of the main active ingredients in Panax ginseng, has multifunctional activity via different mechanisms and neuroprotective effects that are exerted probably via its antioxidant or free radical scavenger action. However, the effects of Rd on spinal cord mitochondrial dysfunction and underlying mechanisms are still obscure. In this study, we sought to investigate the in vitro effects of Rd on mitochondrial integrity and redox balance in isolated spinal cord mitochondria. We verified that Ca²⁺ dissipated the membrane potential, provoked mitochondrial swelling and decreased NAD(P)H matrix content, which were all attenuated by Rd pretreatment in a dose-dependent manner. In contrast, Rd was not able to inhibit Ca²⁺ induced mitochondrial hydrogen peroxide generation. The results of Western blot showed that Rd significantly increased the expression of p-Akt and p-ERK, but had no effects on phosphorylation of PKC and p38. In addition, Rd treatment significantly attenuated Ca²⁺ induced cytochrome c release, which was partly reversed by antagonists of Akt and ERK, but not p-38 inhibitor. The effects of bisindolylmaleimide, a PKC inhibitor, on Rd-induced inhibition of cytochrome c release seem to be at the level of its own detrimental activity on mitochondrial function. Furthermore, we also found that pretreatment with Rd in vivo (10 and 50 mg/kg) protected spinal cord mitochondria against Ca²⁺ induced mitochondrial membrane potential dissipation and cytochrome c release. It is concluded that Rd regulate mitochondrial permeability transition pore formation and cytochrome c release through protein kinases dependent mechanism involving activation of intramitochondrial Akt and ERK pathways.

Injuries of the thoracic aorta and its branches

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Angio-CT imaging of the spinal cord vascularisation: a pictorial essay

Knowledge of the spinal cord (SC) vascular supply is important in patients undergoing procedures that involve the thoracic and thoraco-abdominal aorta; the SC vasculature, however, has a complex and highly variable anatomy. Recent breakthroughs in imaging methods have expanded the non-invasive diagnostic ability to determine a patient's spinal cord vascular pattern, particularly in detecting the presence and location of the artery of Adamkiewicz. CT is the imaging modality of choice for most patients with thoracic and thoraco-abdominal aortic disease for pre-operative planning of endovascular treatment: thus the data set required for our analysis of spinal cord vascular anatomy is already available. This paper provides examples of the SC vasculature imaging that can be obtained with 64 row scanners and appropriate postprocessing.