Venous manifestations of spinal arteriovenous fistulas

Angiographic Index for the Treatment Efficacy and Functional Outcomes of Spinal Cord Arteriovenous Shunts: the Vertebral Blush Sign

BACKGROUND

The functional outcomes in spinal cord arteriovenous shunts (SCAVSs) are usually unpredictable from current assessments of treatment results. We aimed to investigate and propose a new index marker, the vertebral blush (VB) sign, for assessing the treatment efficacy of SCAVSs.

METHODS

This retrospective cohort study enrolled patients diagnosed with SCAVSs between June 2012 and May 2021. The VB sign was defined as the angiographic finding of reappearance or enhanced contrast staining of the vertebral bodies fed by shunt-related arteries observed after shunt occlusion. The primary outcome was the improvement in motor/sensory disturbances or sphincter impairments within 1 year after treatment. The secondary outcome was shunt recanalization. VB sign characteristics and associations with outcomes were analyzed.

RESULTS

Of 65 patients with SCAVSs, 57 were eligible for VB sign assessment; among these, there were 26 with the VB sign and 31 without the VB sign. Among vascular shunts perimedullary arteriovenous fistula showed the greatest difference in prevalence rate between those with and without the VB sign (33.3%, n = 9/27 versus 10.0%, n = 3/30; P = 0.031). On multivariable logistic regression analysis, SCAVSs with the VB sign had significantly more favorable outcomes than those without the VB sign (adjusted odds ratio, 5.61; 95% confidence interval, 1.48-21.23; P = 0.01). There was no relationship between the VB sign and secondary outcomes (P = 0.35).

CONCLUSION

The VB sign is independently associated with functional recovery after shunt occlusion and could be an assessment tool for the treatment efficacy of SCAVSs.

Clinical features and outcomes of perimedullary arteriovenous fistulas: comparison between micro- and macro-type lesions

BACKGROUND

Although the angioarchitecture of perimedullary arteriovenous fistulas (PMAVFs) is straightforward, their size and blood flow are highly heterogeneous. This study aimed to evaluate the differences in clinical features and outcomes of PMAVFs based on lesion size and blood flow.

METHODS

114 consecutive patients with PMAVFs from two institutes were retrospectively reviewed. The lesions were classified as either micro-PMAVFs (shunt point diameter <1 cm) or macro-PMAVFs (shunt point diameter ≥1 cm).

RESULTS

The patients with micro-PMAVFs were older at the first presentation (33.50 vs 13.50 years, p<0.001). Macro-PMAVFs were more commonly associated with spinal metameric arteriovenous shunts (6.9% vs 28.6%, p=0.003). Compared with the macro-PMAVFs, the micro-PMAVFs showed a significantly higher risk of gradual clinical deterioration after initial onset (73.6%/year vs 10.0%/year; HR 3.888, 95% CI 1.802 to 8.390, p=0.001). A total of 58.6% of the micro-PMAVFs were treated surgically, whereas 85.7% of the macro-PMAVFs were treated via endovascular approaches. Complete obliteration was 73.7% for the whole cohort, and was more common for the micro-PMAVFs than for the macro-PMAVFs (87.9% vs 58.9%, p=0.001). At the last follow-up, spinal function was significantly improved compared with the pretreatment status, and the rate of severe disability of patients with macro-PMAVFs was slightly but not significantly higher than that of patients with micro-PMAVFs (16.1% vs 8.6%, p=0.315) CONCLUSIONS: The clinical risks, treatment strategies and obliteration rates of PMAVFs differ based on their size and blood flow.

Pediatric perimedullary arteriovenous fistula: clinical features and endovascular treatments

Objective

Pediatric spinal perimedullary arteriovenous fistula (PMAVF) is rare but may cause permanent disability. We aim to summarize the clinical features of pediatric PMAVFs and our clinical experience in their treatment and to evaluate the effect of endovascular treatment in a large cohort.

Methods

From 2008 to 2017, 51 PMAVFs in pediatric patients (<14 years' old) treated with endovascular techniques were retrospectively reviewed, including 24 type IVb (47.1%) and 27 type IVc (52.9%) lesions. Clinical features, radiological findings, treatment, and outcomes were evaluated.

Results

Thirty-eight boys and thirteen girls were included, and the mean age at presentation was 5.6±4.1 years. Acute neurological deterioration was identified in 33 patients, and 21 of those patients (63.6%) suffered from bleeding. The annual bleeding rate before treatment was 2.55%. After transarterial embolization with coils and glue, 46 PMAVFs (90.2%) were completely occluded, and five (9.8%) were obliterated by supplementary microsurgery. During a follow-up period of 6 to 119 months (mean 58.4±16.7 months), the patients’ clinical states were improved in 42 cases (82.4%), stationary in nine cases (17.6%), and aggravated in none. Type IVc patients had a longer preoperative period, more chronic symptoms, a lower cure rate by embolization, and less improvement of symptoms than type IVb patients had (P<0.05).

Conclusions

Pediatric PMAVF is a special subgroup of intradural arteriovenous shunt that should be treated early. Endovascular embolization is safe and effective in the treatment of pediatric PMAVFs.

Study and therapeutic progress on spinal cord perimedullary arteriovenous fistulas

Spinal cord perimedullary arteriovenous fistulas (PMAVFs) are rare and belong to type IV spinal cord arteriovenous malformations (AVMs). Little is known regarding the treatment and prognosis of spinal cord PMAVFs. In the present study the relevant literature from PubMed was reviewed, and it was found that these fistulas can occur at all ages but are more common in children. In children, most spinal cord PMAVFs are large and with high flow, begin with bleeding and are frequently associated with hereditary hemorrhagic telangiectasia. However, in adults, most spinal cord PMAVFs are small and with low flow and begin with progressive spinal cord dysfunction. The early diagnosis of spinal cord PMAVFs is generally difficult, and symptoms can be very severe at the time of diagnosis. Digital subtraction angiography remains the gold standard; however, computed tomography angiography and magnetic resonance angiography are also promising. Spinal cord PMAVFs can be treated by endovascular embolization, surgical removal or a combination of the two methods. Most spinal cord PMAVFs show good outcomes after the appropriate treatment, and the prognosis is primarily associated with the blood flow of the PMAVF. For high-flow spinal cord PMAVFs, endovascular embolization is more effective and can lead to a good outcome; however, for low-flow spinal cord PMAVFs, surgical removal or the combination with endovascular embolization is the optimal choice. The prognosis for low-flow types is slightly worse than for high-flow spinal cord PMAVFs in children, but the outcome is acceptable.

A case of spinal epidural venous malformation with mediastinal extension: management with combined surgery and percutaneous sclerotherapy

While spinal epidural arteriovenous malformations, fistulas, and shunts are well reported, the presence of a venous malformation in the spinal epidural space is a rare phenomenon. Herein, the authors report the clinical presentation, imaging findings, pathological features, and the outcome of surgical and percutaneous interventional management of a mediastinal and spinal epidural venous malformation in a young woman who presented clinically with neurogenic claudication from presumed venous hypertension precipitating the formation of a syrinx. The patient underwent a C6-T5 osteoplastic laminectomy for decompression of the spinal canal and subtotal resection of the epidural venous malformation, followed by percutaneous sclerotherapy of the mediastinal and residual anterior spinal venous malformation. She developed transient loss of dorsal column sensation, which returned to baseline within 3 weeks of the surgery. A 6-month postoperative MRI study revealed complete resolution of the syrinx and the mediastinal venous malformation. Twelve months after the surgery, the patient has had resolution of all neurological symptoms with the exception of her premorbid migraine headaches. A multidisciplinary approach with partial resection and the use of percutaneous sclerotherapy for the residual malformation can be used to successfully treat a complex venous malformation.

A new classification scheme for spinal vascular abnormalities based on angiographic features

BACKGROUND AND PURPOSE

To determine the interobserver reliability of a newly proposed classification scheme for angiographic classification of spinal vascular malformations including arteriovenous fistulas (AVFs) and arteriovenous malformations (AVMs).

METHOD

A study was performed done in which 1-2 representative angiographic images of 26 spinal AVFs and/or AVMs were independently classified by five fellows in the ACGME accredited Endovascular Surgical Neuroradiology (ESN) program and two external interventionalists in the absence of any other clinical or imaging data. From these observations the interobserver reliability for each category and the overall scheme were determined in terms of the median weighted kappa statistic.

RESULTS

The overall interobserver reliability for the new classification scheme was a Kappa of 0.53 (Z = 21.3, P = <.0001) among the seven raters. The Kappa for individual grades was as follows: grade I (k = 0.66), grade II (k = 0.50), grade III (k = 0.44), and grade IV (k = 0.58). Three or more raters agreed on 100% of the cases. The interobserver reliability was high among the two practicing interventionalist raters (k = 0.55, 95% confidence interval 0.3-0.8). The interobserver reliability remained high among junior ESN fellows (k = 0.65).

CONCLUSION

The new classification scheme provided satisfactory reliability even in the hands of less experienced observers. The scheme can be used with minimal training and other concurrent data and can be relied upon to provide consistent results.

Dural arteriovenous shunts: a new classification of craniospinal epidural venous anatomical bases and clinical correlations

BACKGROUND AND PURPOSE

The craniospinal epidural spaces can be categorized into 3 different compartments related to their specific drainage role of the bone and central nervous system, the ventral epidural, dorsal epidural, and lateral epidural groups. We propose this new classification system for dural arteriovenous shunts and compare demographic, angiographic, and clinical characteristics of dural arteriovenous shunts that develop in these 3 different locations.

METHODS

Three hundred consecutive cases (159 females, 141 males; mean age: 47 years; range, 0 to 87 years) were reviewed for patient demographics, clinical presentation, multiplicity, presence of cortical and spinal venous reflux, and outflow restrictions and classified into the 3 mentioned groups.

RESULTS

The ventral epidural group (n=150) showed a female predominance, more benign clinical presentations, lower rate of cortical and spinal venous reflux, and no cortical and spinal venous reflux without restriction of the venous outflow. The dorsal epidural group (n=67) had a lower mean age and a higher rate of multiplicity. The lateral epidural group (n=63) presented later in life with a male predominance, more aggressive clinical presentations, and cortical and spinal venous reflux without evidence of venous outflow restriction. All differences were statistically significant (P<0.001).

CONCLUSIONS

Dural arteriovenous shunts predictably drain either in pial veins or craniofugally depending on the compartment involved by the dural arteriovenous shunt. Associated conditions (outflow restrictions, high-flow shunts) may change that draining pattern. The significant differences between the groups of the new classification support the hypothesis of biological and/or developmental differences in each epidural region and suggest that dural arteriovenous shunts are a heterogeneous group of diseases.

Venous congestive myelopathy of the cervical spinal cord: An autopsy case showing a rapidly progressive clinical course

We report a rapidly progressive myelopathy in a 74-year-old Japanese man who was admitted to our hospital with a 4-month history of progressive gait disturbance and died of pneumonia followed by respiratory failure on the 22nd day of admission. During the course of his illness, magnetic resonance imaging (MRI) revealed intramedullary lesions with edematous swelling from the medulla oblongata to the spinal cord at the level of the fourth vertebra. After administration of contrast medium, the ventral portion of the lesion was mildly and irregularly enhanced and a dilated vessel was recognized along the ventral surface of the upper cervical cord. At autopsy, ischemic changes were observed in the upper-to-middle cervical cord segments, with so-called arterialized veins in the subarachnoid space. No neoplastic lesions were found within or outside the brain and spinal cord. These pathological findings were essentially those of venous congestive myelopathy (VCM) associated with dural arteriovenous fistulae (AVF), formerly known as Foix-Alajouanine syndrome. VCM associated with dural AVF, which is now considered to be treatable in the early stages, is rare found in the cervical spinal cord. The present autopsy case, with MRI findings, provides further information that might be useful for recognition and diagnosis.

Spinal intradural arteriovenous fistulas acquired in late adulthood: absent spinal venous drainage in pathogenesis and pathophysiology

✓ Intradural spinal arteriovenous fistulas (AVFs), a subtype of spinal arteriovenous malformation in which there is a direct communication between a spinal artery and a vein on the cord surface or in the subarachnoid space, are generally considered to be congenital lesions caused by maldevelopment of the embryonic vascular system. The authors present the cases of two patients with acquired AVFs of the terminal filum. In each patient an AVF between the distal segment of the anterior spinal artery and its accompanying vein on the terminal filum developed within 1 year of repeated lumbar myelography that had demonstrated no evidence of abnormal vascularity. In both patients spinal arteriography demonstrated the absence of medullary venous drainage in the thoracolumbar region, which, combined with the arterialized venous input from the AVF, permitted the development of venous congestion and myelopathy. The involved segment of the terminal filum was excised; in vitro microarteriography and the histopathological examination demonstrated a single, simple arteriovenous connection in both patients.

The findings in these cases indicate that intradural AVF can spontaneously arise in later life. The development of these lesions and/or their clinical manifestation may require not only the presence of the AVF, but also deficiency of medullary spinal venous drainage. The epidemiology and anatomy of intradural AVFs are compatible with an acquired origin in many cases.

Venous congestive myelopathy: a mimic of neoplasia

Venous congestive myelopathy is a progressive disorder frequently associated with arteriovenous fistulas, usually dural. By causing diffuse spinal cord enlargement and enhancement on imaging, it may simulate a neoplasm and prompt a biopsy. We evaluated the biopsy findings in seven such patients (M=5, F=2, mean age 59+/-11 years) who presented variably with progressive lower extremity weakness (86%), bowel and bladder dysfunction (86%), sensory changes (86%) or pain (29%). Preoperative magnetic resonance imaging showed spinal cord enlargement with T2-hyperintensity (86%) and contrast enhancement (57%) at the cervical (14%), thoracolumbar (57%), and/or conus medullaris (57%) level. Prebiopsy spinal angiogram, performed in two patients, was negative. Spinal cord biopsy showed architecturally distorted parenchyma with gliosis and thick hyalinized vessels (100%), variable myelin loss (71%), mild glial atypia (57%), hemosiderin deposition (71%), Rosenthal fibers (43%), vascular thrombosis (29%), and necrosis (29%), features highly suggestive of venous congestive myelopathy. Postbiopsy spinal angiograms were performed in five patients. A dural arteriovenous fistula was identified by selective angiography in three patients, including the two with a negative preoperative angiogram. Additional postbiopsy angiographic studies in two patients were negative, and two patients were followed up without angiography. Mean follow-up after biopsy was 13.6 months. Histologic changes characteristic of venous congestive myelopathy may be seen in spinal cord biopsies with or without an associated fistula. Recognition of this entity by surgical pathologists is important, leading to the correct identification of a non-neoplastic lesion as well as of a surgically treatable disease.