The angiosome territories of the spinal cord: exploring the issue of preoperative spinal angiography. Laboratory investigation

Spinal vascular lesions: anatomy, imaging techniques and treatment

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Vascular myelopathies include different aetiology and mechanism of damage.

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The level of the lesion and the localization within the SC correlates with the clinical symptoms.

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CT, MRI and angiography are essential for diagnosis and treatment playing a complementary role.

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MRI is the gold standard for the evaluation of spinal cord lesions.

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Spinal angiography is the gold standard for evaluation of spinal cord vasculature and vascular malformations.

Background

Vascular lesions of the spinal cord are rare but potentially devastating conditions whose accurate recognition critically determines the clinical outcome. Several conditions lead to myelopathy due to either arterial ischemia, venous congestion or bleeding within the cord. The clinical presentation varies, according with the different aetiology and mechanism of damage.

Purpose

The aim is to provide a comprehensive review on the radiological features of the most common vascular myelopathies, passing through the knowledge of the vascular spinal anatomy and the clinical aspects of the different aetiologies, which is crucial to promptly address the diagnosis and the radiological assessment.

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.

Intraoperative monitoring for spinal radiculomedullary artery aneurysm occlusion treatment: What, when, and how long?

BACKGROUND

Spinal radiculomedullary artery aneurysms are extremely rare. Treatment should be tailored to clinical presentation, distal aneurysm flow, and lesion anatomical features. When a surgical occlusion is planned, it is necessary to evaluate whether intraoperative monitoring (IOM) should be considered as an indispensable tool to prevent potential spinal cord ischemia.

METHODS

We present a patient with symptoms and signs of spinal subarachnoid hemorrhage resulting from the rupture of a T4 anterior radiculomedullary aneurysm who underwent open surgical treatment under motor evoked potential (MEP) monitoring.

RESULTS

Due to the aneurysmal fusiform shape and preserved distal flow, the afferent left anterior radiculomedullary artery was temporarily clipped; 2 minutes after the clamping, the threshold stimulation level rose higher than 100 V, and at minute 3, MEPs amplitude became attenuated over 50%. This was considered as a warning criteria to leave the vessel occlusion. The radiculomedullary aneurysm walls were reinforced and wrapped with muscle and fibrin glue to prevent re-bleeding. The patient awoke from general anesthesia without focal neurologic deficit and made an uneventful recovery with complete resolution of her symptoms and signs.

CONCLUSION

This paper attempts to build awareness of the possibility to cause or worsen a neurological deficit if a radiculomedullary aneurysm with preserved distal flow is clipped or embolized without an optimal IOM control. We report in detail MEP monitoring during the occlusion of a unilateral T4 segmental artery that supplies an anterior radiculomedullary artery aneurysm.

Novel application of 3-dimensional rotational C-arm conebeam computed tomography angiography for metastatic hypervascular tumor mass in the spine

STUDY DESIGN

This is a case report.

OBJECTIVE

To report a 3-dimensional (3D) rotational C-arm conebeam computed tomography (CT) (DynaCT) angiography generating computed tomographic data concurrently with spinal angiographic datasets. This technology allowed 3D modeling of the anterior spinal arterial supply in juxtaposition to a hypervascular tumor mass, thus affording unprecedented guidance in presurgical planning.

SUMMARY OF BACKGROUND DATA

An enhanced demonstration of spatial relationships between the vascular elements and their adjacent soft-tissue structures is needed to visualize the minute anterior spinal artery optimally.

METHODS

A 76-year-old male with a history of renal cell carcinoma metastasis to the T6 vertebra 1 year prior, presented with worsening myelopathy caused by severe spinal cord compression at T6 level, and a plan for surgical decompression was established. Because of the hypervascular nature of this renal cell carcinoma metastasis, preoperative embolization was requested to minimize blood loss during the operation. A digital subtraction angiogram identified the major arterial contribution to the tumor to also supply the radiculomedullary branch to the anterior spinal artery. To further characterize this blood supply, a rotational DynaCT angiography was performed.

RESULTS

The rotationally acquired data were processed generating volumetric CT datasets demonstrating the 3D relationships of the anterior spinal artery, the blood supply to the tumor and the adjacent soft-tissue and bony structures. A shared blood supply to both the tumor mass and the anterior spinal artery from the left T6 segmental artery was confirmed. The dual nature of this blood supply presented increased risk of ischemic spinal cord injury by possible nontarget embolization. Therefore, the embolization was deferred.

CONCLUSION

The DynaCT angiography precisely characterized the complex blood supply of a hypervascular vertebral tumor mass in relation to a shared arterial supply to the thoracic spinal cord. The optimal visualization properly aided presurgical planning.

LEVEL OF EVIDENCE

N/A.

Neurologic complications of aortic diseases and aortic surgery

Aortic disease processes have a wide range of clinical manifestations. The inflammatory disease process of Takayasu's arteritis differs dramatically from the visceral ischemia of aortic dissection. The catastrophic event of aortic rupture tends to overshadow life-altering events such as stroke and paraplegia. However, these neurologic manifestations of aortic diseases have dramatic effects that extend beyond the individual patient to include both social and financial ramifications. This chapter focuses on the major aortic disease processes and how they can initiate, both directly and indirectly, adverse neurologic events. The chapter concludes with a brief discussion of aortic surgery, how interventions on the aorta can cause neurologic complications, and techniques to avoid these feared adverse neurologic outcomes.

Delayed post-traumatic spinal cord infarction in an adult after minor head and neck trauma: a case report

INTRODUCTION

Delayed post-traumatic spinal cord infarction is a devastating complication described in children. In adults, spinal cord ischemia after cardiovascular interventions, scoliosis correction, or profound hypotension has been reported in the literature. However, delayed spinal cord infarction after minor head trauma has not been described yet.

CASE PRESENTATION

We report the case of a 45-year-old Hispanic man who had a minor head trauma. He was admitted to our hospital because of paresthesias in his hands and neck pain. A radiological workup showed cervical spinal canal stenosis and chronic cervical spondylotic myelopathy. Twelve hours after admission, our patient became unresponsive and, despite full resuscitation efforts, died. The autopsy revealed spinal cord necrosis involving the entire cervical spinal cord and upper thoracic region.

CONCLUSIONS

This case illustrates the extreme fragility of spinal cord hemodynamics in patients with chronic cervical spinal canal stenosis, in which any further perturbations, such as cervical hyperflexion related to a minor head injury, can have catastrophic consequences. Furthermore, the delayed onset of spinal cord infarction in this case shows that meticulous maintenance of blood pressure in the acute post-traumatic period is of paramount importance, even in patients with minimal post-traumatic symptoms.

Occlusion of the artery of Adamkiewicz after hip and knee arthroplasty

The artery of Adamkiewicz is the most significant tributary of the anterior spinal artery in the midthoracic region; the occlusion of this artery results in a well-described phenomenon consisting of paraplegia with loss of the sensation of pain, temperature, and touch as well as loss of sphincter control. Proprioception and vibration sense are typically preserved. Although this phenomenon has been associated with several surgeries as well as preexisting aortic abnormalities, the literature thus far has not reported this as a complication of hip or knee arthroplasty. Two case histories are presented.

A Little Talk on Adamkiewicz's Artery. Some Practical Considerations on the Pre-Operative Identification of this Artery Starting from a Single Team Experience in Pre-Surgical Selective Embolization of Vascularized Spinal Lesions

The major radicular artery eponymically named "Adamkiewicz's artery" (AKA) is an important vessel supplying the spinal cord, especially the lumbar enlargement. This report emphasizes the importance of anatomical knowledge of this artery and highlights the concept of the potential risk of neurological complications during different procedures: spine orthopedic/neurosurgery, aortic repair (vascular surgery) and endovascular selective embolizations performed by interventional neuro/radiologists. Anatomical considerations are made on the spinal cord arterial circulation with a special focus on the AKA. Our review of the literature considered this anatomical element essential to compare the potential risk of spinal cord ischemic damage during orthopedic/neurosurgical spine procedures, aortic vascular surgery repair procedures and endovascular selective arterial embolizations. Evaluation of the endovascular selective arterial spine embolization risk was based on our series of 410 embolization procedures. Spinal cord infarction and transient or permanent paraplegia may result from inadvertent interruption of the AKA. The presence of intersegmental collaterals may decrease the risk of spinal cord ischemia: this is an important element to bear in mind that may help in spine surgery or aortic repair procedures performed by vascular surgeons. Nevertheless, during aortic repair (open surgery or stent-graft procedures) interruption of bilateral segmental arteries at multiple consecutive levels including that of the AKA may occur thereby increasing the ischemic spinal cord risk, annulling the benefit of intersegmental collaterals. Accidental embolizations of the AKA during endovascular spine procedures (i.e. selective arterial embolizations) performed by interventional neuro/radiologists will cause an almost certain spinal cord infarction due to the consequent embolizations of the anterior spinal artery (ASA).