Spinal Dural Arteriovenous Fistulas Are Not Associated With Prothrombotic Factors

Unmasking of a spinal dural AV fistula on MRI following steroid administration

Background

Spinal dural arteriovenous fistulas (dAVF) remain a rare, diagnostically challenging and possibly correctable condition with important prognostic outcomes dependent primarily on early detection and treatment.

Case presentation

We present a case of a 73-year-old male with progressively worsening neurological symptoms after steroid administration for a presumed diagnosis of transverse myelitis. This case is extremely unique, as the administration of steroids helped unmask an underlying spinal dural arteriovenous fistula by revealing characteristic imaging findings of a dAVF, not seen on the original MRI study.

Conclusion

In the setting of an unclear cause of transverse myelitis and worsening symptoms following steroid administration, the possibility of a ‘masked’ dural AVF should be considered and repeat imaging performed, which might help in the eventual diagnosis and definitive treatment of this elusive entity.

Thrombosis of the straight sinus and microbleedings due to deep seated arteriovenous fistula - Hemodynamic changes, cognitive impairment and improvement after microsurgery. A technical report

Dural arteriovenous fistulas (dAVF) are rare vascular malformations accounting for only 10-15% that may lead to life threatening deficits due to hemodynamic changes in blood supply and pressure conditions. We present a 64-year old patient who was admitted with disorientation and aphasia. Following images confirmed an infratentorial dural fistula draining into the straight sinus. Additional findings were progressive thrombosis of the straight sinus, microbleedings and bithalamic edema due changes in hemodynamic conditions and venous congestion. Microsurgery was performed. After treatment improvement in clinical condition was observed and the venous congestion was regressive. Hemodynamic changes due to infratentorial dAVFs may lead to bleedings in deep regions and worsening of clinical condition fastly. Treatment requires carefully planning and visualization of angioarchitecture. Symptoms and hemodynamic changes are reversible after treatment, which are essential for treatment decisions.

Patients with cranial dural arteriovenous fistulas may benefit from expanded hypercoagulability and cancer screening

OBJECTIVE

Cranial dural arteriovenous fistulas (DAVFs) have been associated with dural sinus occlusion, and previous reports have suggested the association of hypercoagulability with some cases. But the prevalence of a hypercoagulable state has not been systematically analyzed in conjunction with laboratory markers and clinical manifestations, including history of thromboembolism or systemic malignancy. The authors hypothesize that laboratory or clinical evidence of a hypercoagulable state, including cancer, is commonly identifiable in consecutively identified patients with DAVFs, with implications for clinical management.

METHODS

The retrospective cohort study included all patients older than 17 years with cranial DAVFs diagnosed at University of Chicago Medicine during a 6-year period, whose medical records and imaging results were reviewed for objective laboratory or clinical evidence of a hypercoagulable state, including malignancy. Each case was analyzed for implications on clinical management. Data were analyzed in relation to a systematic review of the literature on this association.

RESULTS

Fifteen (88%) of 17 cases of DAVFs had laboratory (n = 8) or clinical evidence of a hypercoagulable state (thromboembolism [n = 8] or cancer [n = 6]). This hypercoagulability or cancer impacted clinical care in all 15 cases.

CONCLUSIONS

An underlying hypercoagulable state manifested by laboratory testing or clinically, including cancer, is staggeringly common. It is important to recognize this association, along with its impact on the management of the DAVFs and systemic diseases.

Coincidence of Tethered Cord, Filum Terminale Lipoma, and Sacral Dural Arteriovenous Fistula: Report of Two Cases and a Literature Review

Spinal dural arteriovenous fistula (SDAVF) is the most common vascular malformation of the spine in adults. However, the coincidence of tethered cord syndrome, lipoma, and SDAVF on the sacral level is exceptionally rare. We describe two patients, probably the fifth and sixth ever reported. The first was a 33 year-old female who underwent surgical cord de-tethering. Surprisingly, a sacral SDAVF was discovered intraoperatively, despite negative digital subtraction angiography (DSA). The second patient was a 30 year-old male with similar pathologies. After three failed embolizations, the fistula was surgically disconnected. Both patients recovered well. A review of patients with sacral SDAVF coexisting with spinal dysraphism, with an emphasis on the basis of symptoms was done. As a rule, in these coincident disorders, the SDAVF was the direct cause of increasing symptoms. Previous reports and our findings reveal that surgery might be superior to endovascular embolization for treating sacral SDAVFs with coexisting entities, because surgery offers a one-step treatment.

Neovasculature can be induced by patching an arterial graft into a vein: A novel in vivo model of spontaneous arteriovenous fistula formation

Arteriovenous malformations consist of tangles of arteries and veins that are often connected by a fistula. The causes and mechanisms of these clinical entities are not fully understood. We discovered that suturing an arterial patch into the common jugular vein of rabbits led to spontaneous neovascularization, the formation of an arteriovenous fistula and the development of an arteriovenous shunt. An arterial patch excised from the common carotid artery was sutured into the common jugular vein. Within a month, a dense nidus-like neovasculature formed around the patch. Angiography and pulse-oximeter analyses showed that the blood flowing into the neovasculature was arterial blood. This indicated that an arteriovenous shunt had formed. Fluorescence in situ hybridization with a Y chromosome probe in female rabbits that received an arterial patch from male rabbits showed that the vessels close to the graft bore the Y chromosome, whereas the vessels further away did not. Enzyme-linked immunosorbent assays and cDNA microarray analysis showed that multiple angiogenic factors were upregulated after patch transplantation. This is the first in vivo model of spontaneous arteriovenous fistula formation. Further research on these differences may help to improve understanding of human vascular anomaly diseases and the basic principles underlying vasculogenesis and/or angiogenesis.

Spinal dural arteriovenous fistulas: the most frequent vascular malformations of the spinal cord

Spinal dural arteriovenous fistulas are produced by direct communication between the arterial and venous systems of the spinal cord, causing hypertension in the latter with spinal cord dysfunction. It is a rare pathology with unknown etiology and non-specific clinical symptoms that usually results in a delayed diagnosis. Often radiologists are the first to guide the disease towards an adequate diagnosis. Characteristic findings can be seen through MR or MR angiography, and may even locate the fistula in a high percentage of cases, although the pathology must be confirmed by spinal angiography. There are two treatment modalities: endovascular and surgical therapy. Endovascular treatment has improved in recent years with the advantages of a less invasive approach and is therefore usually chosen as primary therapy. In this article we review the main clinical manifestations, imaging findings and treatment of this pathology.

Acute paraparesis and sensory loss following intravenous corticosteroid administration in a case of longitudinally extensive transverse myelitis caused by spinal dural arteriovenous fistula: case report and review of literature

INTRODUCTION

The underlying causes of longitudinally extensive transverse myelitis (LETM) are broad and include inflammatory processes, compression and spinal dural arteriovenous fistula (SDAVF). Presenting symptoms of SDAVF are nonspecific and often go misdiagnosed. Acute clinical deterioration from SDAVF has been described following exertion or valsalva. However, deterioration has been recently recognized following steroid administration and may contribute to increased morbidity.

CASE PRESENTATION

We describe a 63-year-old woman with a 2-year history of intermittent lower extremity numbness and back pain, lumbar stenosis, who presented with subacute worsening of symptoms following a course of oral steroids for an upper respiratory infection. Initial whole-spine imaging was concerning for LETM and lumbar puncture was concerning for an inflammatory process. The patient was treated with intravenous (IV) methylprednisolone, after which she developed acute onset bilateral lower extremity paraparesis with a sensory level. Angiogram confirmed the diagnosis of SDAVF and the patient was treated surgically. Post-operative course was complicated and subsequent clinical improvement has been slow with incomplete recovery to date.

DISCUSSION

This case illustrates the nonspecific presentation of SDAVF and the difficulty of differentiating it from other causes of LETM. It demonstrates acute clinical deterioration of SDAVF following steroid administration, a recently recognized clinical entity. The most likely mechanism is hydrostatic steroid effect coupled with iatrogenic fluid co-administration causing increased venous congestion. Previous cases have demonstrated this effect to be transient and resolves after discontinuation of steroids. This case highlights a recent association of increased morbidity following steroid administration despite definitive treatment.

Cervical spine arteriovenous fistula associated with hereditary haemorrhagic telangiectasia

Reported is a case of a man aged 55 years who presented with progressive spastic paraparesis. Examination demonstrated multiple cutaneous telangiectases. Subsequent development of upper limb weakness, acute urinary retention and eventual respiratory compromise resulted in the requirement for intensive care unit admission and mechanical ventilation. MRI spine revealed diffuse T2 hyperintensity in the cervical cord with enhancement and cord expansion. Immunomodulatory therapy for a presumed diagnosis of transverse myelitis yielded no response, so a vascular aetiology was suspected. Spinal angiography demonstrated an arteriovenous fistula involving the upper cervical cord. Endovascular embolisation was successfully performed and a marked clinical improvement was achieved. Cervical arteriovenous fistulas can cause progressive myelopathy, subarachnoid haemorrhage and brainstem dysfunction. Management typically comprises endovascular embolisation or surgical interruption. A clinical diagnosis of hereditary haemorrhagic telangiectasia was also made in this case, and spinal arteriovenous fistula formation has been associated with this condition.

Venous drainage of the spine and spinal cord: a comprehensive review of its history, embryology, anatomy, physiology, and pathology

Venous drainage of the spine and spinal cord is accomplished through a complex network of venous structures compartmentalized to intrinsic, extrinsic, and extradural systems. As the literature on this topic is scarce, the following review was performed to summarize the available literature into a single coherent format. The medical literature on the spinal venous system was reviewed using online sources as well as historical documents that were not available online in regard to history, embryology, anatomy, and physiology with a particular emphasis on the pathology affecting this system. The spinal venous system is complex and variable. Proper understanding of all aspects is critical for the management of the pathology that results from its failure.

Spinal dural arteriovenous fistula mimicking prostate hyperplasia

BACKGROUND

Initially described in 1926, spinal dural arteriovenous fistula remains diagnostically challenging. Presenting symptoms are often common complaints in general practice or the emergency department, such as leg weakness or numbness. One of the less recognized early features is that of sphincteric disturbance.

OBJECTIVES

To elucidate the underappreciated early feature of urinary sphincter disturbance in spinal arteriovenous fistula.

CASE REPORT

We report on 2 patients with early urinary symptoms that mimicked obstructive uropathy, both of whom sought medical attention on several occasions before the diagnosis was reached. The clinical and imaging findings of spinal dural fistula are discussed.

CONCLUSION

Atypical presentations of bladder dysfunction in addition to other neurologic complaints in the appropriate patient population should prompt spinal imaging to exclude a spinal dural fistula. Timely diagnosis and treatment can prevent the progression of spinal cord edema to infarction with paraparesis, and permanent bladder and bowel dysfunction.

THROMBOPHILIC RISK FACTORS IN PATIENTS WITH CRANIAL AND SPINAL DURAL ARTERIOVENOUS FISTULAE

OBJECTIVE

Numerous studies have reported the technical aspects and results of surgical and/or endovascular treatment of cranial dural arteriovenous fistulae (cDAVF) and spinal dural arteriovenous fistulae (sDAVF). Only a few of them have addressed the question of thrombophilic conditions, which may be relevant as pathogenetic factors or can increase the risk for venous thromboembolic events. Therefore, the objective of this study is to compare thrombophilic risk factors in patients with cDAVF and sDAVF with no history of trauma.

METHODS

A total of 43 patients (25 with cDAVF and 18 with sDAVF) were included in this study. Blood samples were analyzed for G20210A mutation of the prothrombin gene and factor V Leiden mutation. In all patients, prothrombin time, international normalized ratio, fibrinogen, antithrombin, protein C and S activity, von Willebrand factor antigen, ristocetin cofactor activity, D-dimer, coagulation factor VIII activity, and tissue factor pathway inhibitor were determined. Screening was performed for the occurrence of lupus antiphospholipid and cardiolipin antibodies.

RESULTS

The prevalence of G20210A mutation of the prothrombin gene was significantly higher in patients with cDAVF (n = 6) compared with patients with sDAVF (n = 0; P < 0.05, Fisher's exact test). A factor V Leiden mutation was found in 3 patients with sDAVF and in 1 patient with cDAVF (P = 0.29, Fisher's exact test). No significant difference was found for other parameters, except for fibrinogen, but decreased protein C activity was more frequent in patients with cDAVF compared with patients with sDAVF (4 versus 1). Decreased protein S activity was encountered in 3 patients (2 with sDAVF and 1 with cDAVF). Cardiolipin antibodies were found in 2 patients with cDAVF but in none with sDAVF, whereas only 1 patient with sDAVF had lupus antiphospholipid antibodies.

CONCLUSION

In both groups of patients with dural arteriovenous fistulae, genetic thrombophilic abnormalities occurred in a higher percentage than in the general population. The differences of the genetic abnormalities may be involved in different pathophysiological mechanism(s) in the development of these distinct neurovascular entities.

Endovascular and surgical treatment of spinal dural arteriovenous fistulas

INTRODUCTION

The aim of this retrospective study was to evaluate the clinical outcome of patients with spinal dural arteriovenous fistulas (SDAVFs) that were treated with surgery, catheter embolization, or surgery after incomplete embolization.

METHODS

The study included 21 consecutive patients with SDAVFs of the thoracic, lumbar, or sacral spine who were treated in our institution from 1994 to 2007. Thirteen patients were treated with catheter embolization alone. Four patients underwent hemilaminectomy and intradural interruption of the fistula. Four patients were treated by endovascular techniques followed by surgery. The clinical outcome was assessed using the modified Aminoff-Logue scale (ALS) for myelopathy and the modified Rankin scale (MRS) for general quality of life. Patient age ranged from 44 to 77 years (mean 64.7 years).

RESULTS

Surgical as well as endovascular treatment resulted in a significant improvement in ALS (-62.5% and -31.4%, respectively, p < 0.05) and a tendency toward improved MRS (-50% and -32%, respectively) scores. Patients that underwent surgery after endovascular treatment due to incomplete occlusion of the fistula showed only a tendency for improvement in the ALS score (-16.7%), whereas the MRS score was not affected.

CONCLUSION

We conclude that both endovascular and surgical treatment of SDAVFs resulted in a good and lasting clinical outcome in the majority of cases. In specific situations, when a secondary neurosurgical approach was required after endovascular treatment to achieve complete occlusion of the SDAVF, the clinical outcome was rather poor. The best first line treatment modality for each individual patient should be determined by an interdisciplinary team.

THROMBOPHILIC ABNORMALITIES AMONG PATIENTS WITH CRANIAL DURAL ARTERIOVENOUS FISTULAS

OBJECTIVE

Dural sinus thrombosis often accompanies or precedes the development of dural arteriovenous fistulas (DAVFs). Because thrombophilic abnormalities can contribute to sinus thrombosis, we investigated the prevalence of such abnormalities and of venous sinus thrombosis in patients with DAVFs.

METHODS

Thrombophilic factors were measured in 18 patients with DAVFs treated with embolization at our university hospital. Control data were obtained from patients with unruptured intracranial aneurysms. In addition to sinus occlusion, we investigated prothrombin time, activated thromboplastin time, platelet count, and fibrinogen, platelet, antithrombin III, protein C, protein S, anticardiolipin antibody, anti-cardiolipin β2-glycoprotein-I complex antibody, and D-dimer levels.

RESULTS

Of the 18 patients with DAVFs, 16 had abnormal D-dimer levels, whereas the mean values for other thrombophilic factors were nearly normal. D-dimer levels were significantly higher in preoperative DAVF patients than in controls. Interestingly, the mean value of D-dimer was higher in patients with sinus occlusion than in those without it (3.33 versus 1.19). D-dimer levels rose after embolization in eight out of 10 serially tested patients, but, on average, the change was not significant. In clinically cured patients treated more than 3 months before, D-dimer was lower than in preoperative patients.

CONCLUSION

D-dimer is a very sensitive indicator of acute venous thrombosis, suggesting that elevations in patients with DAVFs are likely to reflect sinus thrombosis. D-dimer values decreased and nearly normalized in clinically cured patients during a long-term follow-up period, a finding consistent with completion of thrombosis and cure of the disease. To clarify the correlation between DAVF and sinus thrombosis from the aspect of etiology, we should thoroughly check the variation in the concentration of the thrombophilic factors in the patient with chronic sinus occlusion to know the variation in the fistula formation in the further study.

Thrombophilic factors and the formation of dural arteriovenous fistulas

Object

Dural arteriovenous fistulas (DAVFs) are distinct neurovascular entities. Although their exact origins are unknown, venous thrombosis and venous hypertension are likely to be major inducing factors. To address the relationship between DAVFs and thrombophilic factors, the authors conducted a case-control study at a single institution and performed a metaanalysis of the literature.

Methods

Forty patients with DAVFs at Toronto Western Hospital were recruited to complete a questionnaire and to donate blood samples for factor V Leiden mutation and factor II G20210A mutation screening and assessment of coagulation factors. The questionnaire was designed to collect information on each participant's specific history of venous thrombosis, medications, and race. A control group of 33 healthy volunteers agreed to the same protocol. A MEDLINE search of the literature from 1966 to the present was conducted and three relevant series were found. The results of the present study were pooled with the data from the literature.

Results

Combining institutional results with the results from the literature yielded a total of 121 patients and 178 control group members. Thrombophilic mutations were present in 16 patients and four healthy volunteers, with an odds ratio (OR) of 4.69 for factor V Leiden (95% confidence interval [CI] 1.24–17.69) and an OR of 10.87 for the prothrombin G20210A allele (95% CI 1.32–89.51). Levels of the basic coagulation profile, fibrinogen, and factor VIII were within normal limits.

Conclusions

Patients with the factor V Leiden and factor II G20210A mutations are at a higher risk for DAVFs. However, because these mutations are not implicated in the vast majority of DAVFs, routine screening is not recommended.

Thoracic radicular vessels by simultaneous intra-arterial and intravenous injection of araldite

Spinal dural arteriovenous fistulas (SDAVF) consist of a shunt between a radicular artery and a radicular vein, resulting in a progressive paraparesis. They are most prevalent in middle-aged men (male to female ratio 5 to 1). It is unknown why the shunt develops. It is possible that there are anatomical differences between men and women, which may account for the sex difference in prevalence. We performed a study with simultaneous arterial and venous araldite injection in 5 male and 5 female human cadavers using different colors. The mean age of the human cadavers was 78 years (range 70-91). The human cadavers were not known to have suffered from spinal disease. We did not find significant differences in thoracic vasculature between men and women. Two different types of radicular arteries could be identified: The first was the arterial feeder of the root ganglion or the dura mater, which is also called the distal radicular artery. The second was the tributary of the anterior spinal artery, which is also called the medullary artery. We found three arteriovenous anastomoses between the radicular artery and the corresponding vein, and three between the radicular artery and venous plexus. We found a total of six thoracic arteriovenous shunts in four cadavers but their role in the pathogenesis of SDAVF remains uncertain. No vascular anatomic differences between men and women were found.

Spinal dural arteriovenous fistula

PURPOSE OF REVIEW

To summarize clinical key points, diagnostic features, and results of imaging and therapy of spinal dural arteriovenous fistula (SDAVF).

RECENT FINDINGS

SDAVF accounts for 70% of spinal arteriovenous malformation with an annual incidence of 5-10 cases per million. At least 80% of patients are male, and more than 66% of patients are in the sixth and seventh decade of life indicating preponderance of gender and age. Thrombophilia is not a predisposing factor of disease. Clinical course is predominated by symptoms of congestive myelopathy, but subarachnoid hemorrhage may occur. Double SDAVF is a rare problem in the management of disease. Magnetic resonance imaging has replaced myelography as screening procedure. Contrast-enhanced magnetic resonance angiography and multislice computerized tomographic angiography may facilitate diagnostic procedure, however, spinal angiography is still required to confirm diagnosis. Treatment by permanent occlusion of fistula results in clinical improvement in 70% of cases. Microsurgical shunt interruption has proven secure and reliable. Endovascular shunt embolization has been established as a standardized procedure, but occlusion rates are still lower than in surgical treatment.

SUMMARY

Advances have been made in diagnosis and treatment of SDAVF, but the disease is still not completely understood.