Spinal Dural Arteriovenous Fistulas: A Review

Surgical Management of Spinal Dural Arteriovenous Fistula: A Case Report

Spinal dural arteriovenous fistulas (SDAVFs) are the most commonly encountered vascular malformation of the spinal cord and a treatable cause of progressive myelopathy. They most commonly affect elderly men and are classically found in the thoracolumbar region. The arteriovenous shunt is located inside the dura mater close to the spinal nerve root where the arterial blood from a radiculomeningeal artery enters a radicular vein. The increase in spinal venous pressure leads to the decreased drainage of normal spinal veins, venous congestion, and the clinical findings of progressive myelopathy. We report the case of a 62-year-old patient who presented with spastic paraparesis 3/5 bilaterally, with thermalogic hypoesthesia, hyperreflexia, and genito-sphincter disorders. Spinal cord MRI and spinal cord arteriography confirmed the diagnosis of dorsal dural arteriovenous fistula regarding D11, which was excluded by surgical technique, with the disappearance of serpiginous venous dilatations in the perimedullary vein. A good postoperative clinical evolution has been noted, with a clear improvement in the deficit. We report the case of a patient with a dorsal medullary dural fistula; we will discuss the clinical and neuroimaging presentation of the dorsal spinal dural fistula and the surgical management.

Angioarchitecture Classification and Treatment Modalities of Craniocervical Junction Arteriovenous Fistulas: A Cohort Study of 155 Patients

BACKGROUND AND OBJECTIVES

Craniocervical junction (CCJ) arteriovenous fistulas (AVFs) are rare. Variability in clinical manifestations and treatment strategies for CCJ AVFs stems from differences in their angioarchitecture. Our study aims to categorize CCJ AVFs based on their angioarchitecture and explore the associated clinical features and treatment modalities for distinct CCJ AVF types.

METHODS

The authors conducted a retrospective analysis of patients with CCJ AVFs treated at a single neurosurgical facility over the past decade. These patients were classified based on the angioarchitecture of their CCJ AVFs. The analysis included an evaluation of angioarchitecture, clinical characteristics, treatment strategies, and outcomes.

RESULTS

The study included 155 patients, with a median age of 56 years, collectively manifesting 165 CCJ AVFs. Our classification identified 4 distinct CCJ AVF types: epidural AVFs (19 [11.5%]), dural AVFs (98 [59.4%]), radicular AVFs (33 [20.0%]), and perimedullary AVFs (15 [9.1%]). Further differentiation was applied based on the presence of pial feeders. The predominant fistula location was at cervical-1 (77.0%). Ascending intradural drainage (52.7%) and descending intradural drainage (52.1%) were frequently observed drainage patterns. Patients with dural AVF predominantly presented with venous hypertensive myelopathy, whereas patients with other types of CCJ AVFs showed a higher incidence of subarachnoid hemorrhage (P = .012). Microsurgery was the predominant treatment, applied in the management of 126 (76.4%) AVFs, whereas 8 (4.8%) AVFs exclusively underwent interventional embolization and 25 (15.2%) received a combination of interventional embolization and microsurgical treatment.

CONCLUSION

CCJ AVFs can be distinguished based on the fistula location and the arterial feeders. Currently, microsurgery stands as the preferred treatment strategy for CCJ AVFs, whereas interventional embolization plays a distinctive role in cases with specific angioarchitecture or as a pretreatment measure before microsurgery.

The hybrid operation based on microsurgery assisted by intraoperative spinal angiography in patients with spinal dural arteriovenous fistula: a series of 45 cases from multicenter research

BACKGROUND

To assess the clinical effects of hybrid surgery, which includes spinal angiography-assisted microsurgery, in the treatment of spinal dural arteriovenous fistulas (SDAVF).

METHODS

We retrospectively reviewed 45 patients who underwent hybrid Spinal dural arteriovenous fistula (SDAVF) resection between September 2019 and June 2022. The hybrid surgery involved intraoperative digital subtraction angiography (DSA) of the spinal vessels to determine the source of the blood-supplying artery, location of the fistula and draining vein, indocyanine green fluorescence (ICG)-assisted microsurgical resection of the fistula, and postoperative DSA to verify therapeutic efficacy. The Hamilton Anxiety Scale (HAMA), Hamilton Depression Scale (HAMD), Visual Analog Scale (VAS), Barthel score, modified Rankin Scale (mRS) and modified Aminoff-Logue score (key indicator) were used to assess the clinical effects of SDAVF resection.

RESULTS

A series of 45 patients with SDAVF were successfully treated with hybrid surgery without fistula recurrence. There were no intraoperative complications related to spinal angiography, and none of the patients died. Postoperatively, two patients experienced clinical deterioration of spinal cord function, which manifested as bilateral lower extremity paralysis and bladder sphincter dysfunction. Postoperatively, improvement in mALS scores was observed in 16 cases (35.6%) within 1-2 days, 12 cases (26.7%) at 1 week, and 7 cases (15.6%) at 6 months. No SDAVF recurrence was detected in the spinal MRA examination 6 months after surgery. When compared with preoperative mALS scores, 35 cases (77.8%) showed significant improvement in symptoms, 8 cases (17.8%), remained unchanged, and 2 cases (4.4%) deteriorated. Compared with the preoperative scores, the postoperative mALS score was significantly decreased [postoperative vs. preoperative: 2(1,3) vs. 3(2,4)], HAMD score [(12.2 ± 5.5) vs. (19.6 ± 6.3)], HAMA score [(15.6 ± 5.5) vs. (20.5 ± 6.5)], and VAS score [3(2,5) vs. 5(4,8)]. Conversely, Barthel scoresshowed significant increase [(74.6 ± 8.7) vs. (67.8 ± 9.2)] (P < 0.05). However, the mRS scores were lower than preoperatively [1(1,2) vs. 2(1,2.5)], but the difference was not statistically significant (P > 0.05). There was a significant increase in "good" neurological outcomes at follow-up compared with preoperative function (62.2% vs. 33.3%) (P = 0.023).

CONCLUSION

Hybrid surgery is a safe and effective treatment for patients with SAVF, which is beneficial for improving anxiety, depression, spinal cord, and neurological function, and relieving pain. However, the treatment of patients with SDAVF is a complex, long-term process requiring further multidisciplinary interventions, including clinical care, psychosocial interventions, and neurorehabilitation.

Risk factors for postoperative late deterioration in patients with spinal dural arteriovenous fistulas

Background

Approximately 86% of patients with spinal dural arteriovenous fistulas (SDVAFs) exhibit clinical improvement after surgery. However, 12%-55.8% of these patients experience late deterioration (LD) after an initial period of improvement. The risk factors for LD remain unclear. The aim of this study was to explore the risk factors for LD in SDVAF patients.

Methods

The clinical data of patients who were admitted to two tertiary hospitals between June 2014 and May 2022 were reviewed. Patients were divided into two groups: the LD group and the no LD group. The severity of neurological dysfunction (NDF) was evaluated using the Modified Aminoff and Logue Scale. Univariable and multivariable Cox regression analyses were performed.

Results

A total of 105 eligible patients were enrolled, with a mean age of 57.55 ± 9.42 years. The LD group comprised 37 individuals, while the no LD group consisted of 68 individuals. According to the univariable analysis, preoperative NDF severity and treatment strategy were associated with the risk of LD. According to the multivariable analysis, patients who underwent microsurgery (MS) had a lower risk of LD than did those who underwent endovascular treatment (EVT; HR 0.197, 95% CI 0.085-0.457), and patients with severe NDF had a higher risk of LD than did those with mild NDF (HR 3.604, 95% CI 1.226-10.588), whereas the risk of LD in patients with moderate NDF was similar to that of patients with mild NDF (HR 1.352, 95% CI 0.519-3.524).

Conclusion

EVT and severe preoperative NDF are independent risk factors for LD.

Histopathological analysis of the wall enhancement of the spinal dural arteriovenous fistulae's draining veins

OBJECTIVE

The mechanism behind SDAVF is still unclear. We discovered that the vessel wall of the SDAVF-DV occasionally showed enhancement in MRI, and this study assessed the relationship between the enhancement of the draining vein's wall and its histology.

METHODS

For histopathologic analysis, 16 draining vein samples from 16 patients with SDAVF were included, 3 normal arteries and 3 normal veins were chosen as comparison. We assessed the imaging and microscopic characteristics of the draining veins in SDAVF patients. The former included the presence of significant enhancement of the wall of the draining vein in MRI, and the latter included the adherence, aggregation, infiltration of pro-inflammatory factors and inflammatory cells. Immuno-histochemical staining was performed using IL-1β, IL-8, TGF-β as well as MPO and MMP-9, and positive results were counted. Multiple logistic regression analysis was used to determine whether the infiltration of inflammatory cells was connected to vessel wall enhancement in the SDAVF-DV.

RESULTS

Infiltration of inflammatory cells was significantly higher in SDAVF-DV compared to normal vessels, 7 out of 16 patients significantly had enhancement of the vessel wall of SDAVF-DV, and logistic regression analysis showed that samples with more infiltration of inflammatory cells were more likely to show enhancement of the SDAVF-DV walls.

CONCLUSION

There was considerable inflammatory cells infiltration in SDAVF-DV, and this may explain why their vessel wall had such a significant enhancement in MRI.

Extravertebral low back pain: a scoping review

BACKGROUND

Low back pain (LBP) is one of the most common reasons for consultation in general practice. Currently, LBP is categorised into specific and non-specific causes. However, extravertebral causes, such as abdominal aortic aneurysm or pancreatitis, are not being considered.

METHODS

A systematic literature search was performed across MEDLINE, Embase, and the Cochrane library, complemented by a handsearch. Studies conducted between 1 January 2001 and 31 December 2020, where LBP was the main symptom, were included.

RESULTS

The literature search identified 6040 studies, from which duplicates were removed, leaving 4105 studies for title and abstract screening. Subsequently, 265 publications were selected for inclusion, with an additional 197 publications identified through the handsearch. The majority of the studies were case reports and case series, predominantly originating from specialised care settings. A clear distinction between vertebral or rare causes of LBP was not always possible. A range of diseases were identified as potential extravertebral causes of LBP, encompassing gynaecological, urological, vascular, systemic, and gastrointestinal diseases. Notably, guidelines exhibited inconsistencies in addressing extravertebral causes.

DISCUSSION

Prior to this review, there has been no systematic investigation into extravertebral causes of LBP. Although these causes are rare, the absence of robust and reliable epidemiological data hinders a comprehensive understanding, as well as the lack of standardised protocols, which contributes to a lack of accurate description of indicative symptoms. While there are certain disease-specific characteristics, such as non-mechanical or cyclical LBP, and atypical accompanying symptoms like fever, abdominal pain, or leg swelling, that may suggest extravertebral causes, it is important to recognise that these features are not universally present in every patient.

CONCLUSION

The differential diagnosis of extravertebral LBP is extensive with relatively low prevalence rates dependent on the clinical setting. Clinicians should maintain a high index of suspicion for extravertebral aetiologies, especially in patients presenting with atypical accompanying symptoms.

Diagnostic, clinical management, and outcomes in patients with spinal dural arteriovenous fistula

Background

Spinal dural arteriovenous fistulas (SDAVFs) are rare spinal vascular malformations, but account for 70 to 80% of all spinal arteriovenous malformations. SDAVFs can be treated either surgically or endovascularly, with surgical treatment appearing to lead to higher closure rates. Our aim was to analyze the demographic data, diagnostic history, treatment characteristics and clinical short- and long-term outcomes.

Methods

The medical records of 81 patients who underwent surgical (n = 70, 86.4%) and endovascular (n = 11, 13.6%) treatment for SDAVF at a university hospital between 2002 and 2023 were retrospectively analyzed.

Results

SDAVF was observed more frequently in men than women (61, 75.3% vs. 20, 24.7%) with a mean age of 63.5 ± 12.7 years and a mean duration of symptoms to diagnosis of 12.0 ± 12.8 months. The most common first symptom was gait disturbance (36, 44.4%), followed by sensory disturbance (24, 29.6%). The location of the fistula point was most common in the lower thoracic region (36, 44.5%), followed by the lumbar region (23, 28.4%). Incomplete or failed occlusion of the fistula occurred in 8 patients (9.9%), with 6 patients (7.4%) undergoing further treatment either surgically or endovascularly. Treatment- or hospital-related complications were observed in 16 patients (19.8%). A single-level laminectomy was the most common approach (31, 44.3%), followed by single-level hemilaminectomy (28, 40.0%), and unilateral interlaminar fenestration (11, 15.7%). Back pain or radiculopathy was observed in 58% of patients (47/81) pre-treatment and had already decreased to 24.7% at hospital discharge (p < 0.001). No significant differences were observed in sensory disturbances (p = 0.681). The median of American Spinal Injury Association motor score (ASIA-MS) was 94 [82.5-100] at admission, 98 [86.5-100] at hospital discharge, 100 [90-100] at the first, second, and third follow-up (p = 0.019). The median modified Aminoff-Logue scale (mALS) was 5 [2-7] at admission, 3 [1-6] at hospital discharge, 2 [1-5] at the first follow-up, 2 [0.5-5] at the second follow-up and 2 [1-7] at the third follow-up (p = 0.006).

Conclusions

SDAVF occurs predominantly in men in the 6th decade of life and can be safely and effectively treated surgically and endovascularly, improving symptoms such as pain and motor deficits, gait disturbances as well as bowel and bladder dysfunction, but not sensory disturbances.

Knowledge, attitudes and practices regarding spinal vascular malformations among doctors in China: a cross-sectional study

OBJECTIVE

Knowledge, attitude and practice (KAP) models are essential tools for assessing healthcare professionals' understanding, beliefs and behaviours towards specific health issues. This study aimed to explore the KAP of Chinese doctors in diagnosing and treating spinal vascular malformations (SVM).

DESIGN

A web-based cross-sectional survey.

SETTING

This study was conducted between October and December 2022 through a self-administered questionnaire.

PARTICIPANTS

Participants include full-time doctors who voluntarily participate. Doctors in advanced training, regular training or internships were excluded.

PRIMARY AND SECONDARY OUTCOME MEASURES

The KAP scores of Chinese doctors in diagnosing and treating SVM measured by the questionnaire.

RESULTS

A total of 517 doctors participated in the study, mostly in Shaanxi, China, working in SVM-relevant departments (n=396) or other departments (n=121). The doctors achieved an average knowledge score of 9.66±1.95 (range: 0-12), attitude score of 22.16±1.71 (range: 6-30) and practice scores of 46.13±5.35 for those in SVM-relevant departments (neurosurgery, orthopaedics and neurology) and 8.50±1.25 for those in other departments, respectively, revealing doctors have adequate knowledge, positive attitude and good practice, and those in SVM-relevant departments showing more adeptness compared with those in other departments. Moreover, multivariate logistic regression analysis showed that knowledge about SVM (OR=1.72, 95% CI 1.11 to 2.65, p=0.015), holding a master's degree (OR=1.85, 95% CI 1.14 to 3.00, p=0.013) and working in orthopaedics (OR=0.34, 95% CI 0.13 to 0.88, p=0.026) were independently associated with good attitude.

CONCLUSION

Chinese doctors showed adequate knowledge, moderate attitudes and good practice regarding SVM. A continuing education programme may improve clinical practitioners' ability to manage SVM.

Rupture of a Spinal Dural Arteriovenous Fistula as a Differential Diagnosis of a Coronary Syndrome: Case Report

BACKGROUND AND IMPORTANCE

Spinal dural arteriovenous fistulas (SDAVFs) are the most common vascular malformation of the spine and can lead to progressive paraplegia if left untreated. However, because of their nonspecific clinical presentation, they are often misdiagnosed as other pathologies, such as discopathies or degenerative neuropathies, which can result in delayed diagnosis and treatment.

CLINICAL PRESENTATION

A case of a 73-year-old female with a history of acute coronary syndrome who presented to the emergency department with sudden onset chest pain suggestive of an acute myocardial infarction is presented. Further evaluation revealed a subdural hematoma at T2-T5 and T8-L5, caused by a ruptured SDAVF at the T12-L1 level. The patient required emergency decompression surgery, but because of late diagnosis, she suffered a spinal cord injury with an ASIA-A classification.

CONCLUSION

SDAVF is a disease with nonspecific initial symptoms, which can easily be mistaken for other pathologies. However, early recognition of the presence of the fistula, especially in cases of rupture, can improve prognosis and increase the chance of better outcomes. It is important to keep this condition in mind when evaluating patients with unexplained neurological symptoms and consider SDAVF as a differential diagnosis of acute coronary syndrome.

Functional Vascular Anatomy and Arteriovenous Shunts of the Spine

The history of vascular anatomy of the spinal cord and spine began in the late 19th century. With recent advances in endovascular and surgical treatment of vascular lesions of the spinal cord, understanding the vascular anatomy of the spinal cord has become more important than ever. Catheter angiography is the gold standard for diagnosing vascular lesions of the spinal cord, and the vascular architecture of the spinal cord itself is relatively simple, a repetition of basic longitudinal and axial structures. This review discusses the vascular anatomy of the spine and spinal cord from the embryological point of view, as well as an overview of typical spinal arteriovenous shunt diseases mainly depending on their locations: paraspinal, epidural, dural, perimedullary, intramedullary, filum terminale/cauda equina, craniocervical junction, and related diseases.

Surgical Management of a Spinal Dural Arteriovenous Fistula

Spinal dural arteriovenous fistulas (SDAVFs) may have subtle clinical presentations and are often misdiagnosed. Clinical status gradually deteriorates following symptom onset making prompt identification and management essential. Here we present a case of a 67-year-old patient with rapidly progressing motor and sensory deficits to eventual right hemiplegia. Following imaging and surgical intervention, a thoracic SDAVF was identified and resected. This case report highlights a unique SDAVF with a stroke-like presentation. For patients with such presentation, without a clear source of intracranial pathology, spinal causes such as SDAVF could be considered.

Imaging characteristics, misdiagnosis and microsurgical outcomes of patients with spinal dural arteriovenous fistula: a retrospective study of 32 patients

Background

Spinal dural arteriovenous fistula (SDAVF) is an extremely rare spinal vascular malformation. As SDAVF exhibits no specific clinical manifestations nor diverse imaging results, it is easily misdiagnosed, resulting in delayed treatment and irreversible neurological damage. Most patients were initially misdiagnosed, but there were few reports on reducing misdiagnosis.

Methods

A total of 32 consecutive patients, who presented to our institution (Shanghai Deji Hospital) with SDAVF between June 2013 and January 2016 were retrospectively analyzed. Data were collected on demographics, clinical presentation, imaging findings, follow-up, and clinical outcomes. The Aminoff-Logue scale (ALS) was used to assess clinical outcomes.

Results

Of the 32 enrolled patients (3 females, mean age 59.1±3.8 years), 23 patients (71.9%) were misdiagnosed as acute myelitis (11 patients), intramedullary tumors (6 patients), lumbar disc herniation (4 patients), and other conditions (2 patients). All patients underwent surgical procedures under electrophysiological monitoring. Fistulas were found in all 32 patients and were successfully occluded. The mean follow-up period was 19.22±8.21 months (ranging from 2 weeks to 30 months). One year later, 20 patients underwent magnetic resonance imaging (MRI), and 14 showed no T2 edema, and the edema was relieved in 6 patients. A total of 10 patients underwent enhancement MRI and no enhancement signs were detected. Among the 27 patients with long-time follow-up, the fistula had no residual or recurrence, 21 patients showed decreased ALS scores (P<0.05). Six patients exhibited nonsignificant improvement. No aggravating patient was found. Prognosis differed significantly between patients with ALS <6 and those with ALS ≥6 (P<0.05).

Conclusions

Spinal angiography should be performed with full intubation, and microcatheter angiography can reduce misdiagnosis. SDAVF must be differentiated from acute myelitis, intramedullary tumor, and other spinal vascular malformations. Microsurgical treatment is effective with a low recurrence rate.

Pathophysiology and classification of intracranial and spinal dural AVF

Dural arteriovenous fistulas (DAVFs) are pathologic shunts between pachymeningeal arteries and dural venous channel. DAVFs are relatively rare, however, DAVFs can lead to significant morbidity and mortality due to intracranial hemorrhage and non-hemorrhagic neurologic deterioration related to leptomeningeal venous drainage. The etiology and pathophysiology of DAVFs is not fully understood. Several hypotheses for development of DAVF and classifications for predicting risk of hemorrhage and neurological deficit have been proposed to help clinical decision making according to its natural history. Herein, incidence, etiology, pathophysiology of development of intracranial and spinal DAVF including their classifications are briefly described with short historical review.

Spinal dural arteriovenous fistula rupture after Rathke's cleft cyst endoscopic resection: Case report and literature review

Background:

Spinal dural arteriovenous fistula (SDAVF) is the most frequent vascular malformation of the spine and accounts for approximately 70% of all vascular spinal malformations. In rare cases, SDAVF rupture and subsequent subarachnoid hemorrhage or intramedullary hematoma may occur. The aim of this article is to present a fatal case of SDAVF rupture after a Rathke’s cleft cyst (RCC) endoscopic resection.

Case Description:

An 80-year-old female was referred to our hospital with a clinical presentation of bilateral reduction in visual acuity, bitemporal hemianopsia, and sellar magnetic resonance imaging (MRI) highly suggestive of RCC. After the first endonasal endoscopic surgery, the cyst was partially removed and vision improved. No signs of cerebrospinal fluid (CSF) leak were observed. After 1 year, the patient returned because of RCC recurrence and decreased visual acuity. In the second procedure, the lesion was totally resected and CSF leak was observed. A nasoseptal flap was rotated to cover the skull base defect. The patient developed subtle paraparesis followed by paraplegia on the 4^th postoperative day. The dorsal spine MRI revealed a T3-T4 intramedullary hematoma. A dorsal laminectomy was performed and a SDAVF was observed. During microsurgery, at the right T3 nerve root level, an arteriovenous shunting point was identified, coagulated, and divided. The intramedullary hematoma was evacuated. The patient developed neurogenic and septic shock and died.

Conclusion:

Venous hypertension, venous wall fragility, and venous thrombosis seem to be the main factors involved in SDAVF rupture. In this particular case, reduction of the extravascular pressure and sudden variation in the pressure gradient caused by sustained CSF leak, also appeared to play an important role in SDAVF rupture. It may represent one more complication related to radical resection of RCC.

Endovascular treatment of a sacral dural arteriovenous fistula

Spinal dural arteriovenous fistula (SDAVF) is a rare pathological communication between arterial and venous vessels within the spinal dural sheath. Clinical presentation includes progressive spinal cord symptoms including gait difficulty, sensory disturbances, changes in bowel or bladder function, and sexual dysfunction. These fistulas are most often present in the thoracolumbar region. Diagnoses of SDVAFs are commonly missed, possibly due to the low index of suspicion, non-specific symptoms and challenging imaging. In this case report, we describe a rare presentation of a sacral SDAVF which was detected by collective efforts between endovascular neurosurgery and interventional radiology. We outline the diagnostic and imaging challenges we faced to discover the fistula. In particular, mechanical pump injection instead of hand injection during angiography was required to reveal the fistula. Following identification, the fistula was successfully treated endovascularly by using onyx (ethylene vinyl alcohol glue), a less invasive alternative to surgical intervention.

The Top-100 most cited articles on dural arteriovenous fistula: A bibliometric analysis

Objective

Dural arteriovenous fistula (DAVF) is a rare pathological vascular lesion with variable clinical manifestations. Since 1968, several articles have been published to address spinal and cranial DAVFs. The aim of this study is to identify, analyse, and review the pertinent literature of the top-100 most cited articles on DAVFs published to date.

Methods

A title-specific, keyword-based search with no time restriction was performed in June 2020. The Scopus database was used to identify the top-100 most cited articles on DAVFs. The term “dural arteriovenous fistula” was used as a search keyword. The search results were arranged in descending order based on the total citation count. The top-100 articles were categorized into ten categories.

Results

Between 1968 and 2020, a total of 2298 articles were published on DAVFs. The top-100 most cited articles were published between 1983 and 2012. The total number of citations for the top-100 articles was 12393 (123 citations/article). Most articles (34%) were investigating the clinical aspect of DAVFs. The country contributing to the most impactful and highest volume of publications (46%) was the United States. The Mayo Clinic was the most active institute in contribution. Most articles (29%) were published by the Journal of Neurosurgery.

Conclusions

In the top-100 most cited articles on DAVF, most studies were published in neurosurgery/neuroradiology-dedicated journals. This bibliometric analysis identifies the publication trends and provides a comprehensive overview of the most influential articles addressing DAVFs.

Surfer Myelopathy in Children: A Case Series Study

OBJECTIVE

The cause of surfer myelopathy remains enigmatic and long-term follow-up outcomes are not well documented. In the present study, the mechanisms underlying surfer myelopathy in children are analyzed and the long-term follow-up outcomes are reported.

METHODS

Clinical data from 3 institutions were retrospectively analyzed. Patients were assessed using the American Spinal Injury Association Impairment Scale (AIS) on admission and at follow-up. The mechanisms were studied by analyzing patients' medical history, magnetic resonance imaging, and magnetic resonance angiography. The prognosis of long-term follow-up was summarized.

RESULTS

Thirty-one children were diagnosed with surfer myelopathy. Intramedullary high-intensity T2 signal from mid to lower thoracic level to conus was found during the acute stage. Follow-up magnetic resonance imaging in the subacute stage showed cranial progression of the T2 hyperintensity up to 1-10 vertebral segments, and no neurologic deterioration was found. Intramedullary lesion length between the complete and incomplete injury was significantly different (P < 0.01) in the subacute phase. Flow voids around nerve roots and in the epidural space were detected in 18 patients and 15 patients, respectively, on axial T2-weighted imaging. Enlarged tortuous veins were found in 3 of 6 patients who underwent spinal magnetic resonance angiography, which were discontinuous around nerve root. During long-term follow-up, no patients with AIS grade A recovered, and atrophic cord was observed in the later stage in 14 patients. Patients with incomplete injury had different recoveries.

CONCLUSIONS

Surfer myelopathy in children is caused by spinal venous hypertension. The AIS grade on admission is a predictor of prognosis.

Spinal Vascular Malformations: Treatment and Outcome

BACKGROUND

Vascular malformations of the spinal cord are a rare and complex clinical entity and can lead to severe morbidity with progressive spinal cord symptoms if not treated properly. In early stages, the disease is characterized by slowly progressive, nonspecific symptoms, such as gait disturbance, paresthesia, diffuse sensory symptoms, and radicular pain; in the late stages, bowel and bladder incontinence, erectile dysfunction, and urinary retention may develop. In recent decades, understanding and treatment of spinal vascular malformations have improved with the evolution of diagnostic tools and treatment modalities; however, it is still difficult to manage these cases because of the complexity of the pathology. The aims of this study were to present the long-term outcomes of our patients and to discuss the optimal management strategies.

METHODS

We reviewed the records of 78 patients with spinal vascular malformations and performed a retrospective, single-center case series evaluating initial occlusion, recanalization, retreatment, and neurologic status of patients with dural arteriovenous fistulas, perimedullary arteriovenous fistulas, arteriovenous malformations, and extradural arteriovenous fistulas who had undergone embolization and/or surgery.

RESULTS

No mortality was observed. Complete obliteration was achieved in 76 patients (97.4%).

CONCLUSIONS

Both endovascular and surgical treatment of spinal vascular malformations resulted in significant long-term recovery from myelopathic symptoms and improvement in quality of life for most patients.

Type I AV fistula of the thoracic spinal cord

Type I AV fistulas of the spinal cord are exceedingly rare. The average age at diagnosis is 50. Clinical presentation is often very non-specific, and sensory deficits and sphincter dysfunction may also occur. Neurological deterioration is generally gradual. Thus, failure to diagnosis frequently results in permanent disability. A 22-year-old female complained of a "muscle spasm" in the midline thoracic area with no history of trauma or prior occurrence. She also experienced bilateral lower extremity weakness/numbness and perianal anesthesia. She is a healthy female with no medical problems. Exam revealed lower extremity motor function of 1/5 as well as diminished sensation. A foley catheter was placed for urinary retention. The remainder of the neurological exam was normal. MRI demonstrated a lesion at the fourth thoracic level with significant cord compression. The patient was taken emergently to the operating room by neurosurgery. This case demonstrates a rare disorder occurring in a 22-year old female, far younger than the typical 50-year old patient. Moreover, the lesion was located in the thoracic rather than the typical lumbar cord. Symptoms may be misinterpreted as a peripheral nerve lesion and delay time to diagnosis. Early diagnosis remains critical to prevent permanent neurologic sequelae. AV fistula should remain high on the differential of patients presenting with back pain and focal neurologic complaints.

The Hybrid Assistive Limb® intervention for a postoperative patient with spinal dural arteriovenous fistula and chronic spinal cord injury: A case study

CONTEXT

The purpose of this report was to describe the improvement in walking ability using the Hybrid Assistive Limb® (HAL®) intervention in the case of a patient with paraplegia after spinal cord injury whose condition deteriorated because of a spinal dural arteriovenous fistula (SDAVF).

FINDINGS

A 48-year-old man started the HAL® intervention twice per week (total 10 sessions), after his neurologic improvement had plateaued from 3 to 6 months postoperatively for an SDAVF. During the HAL® intervention, the 10-m walk test (10MWT) without HAL® was performed before and after each session. An electromyography system was used to evaluate muscle activity of both the gluteus maximus (Gmax) and quadriceps femoris (Quad) muscles in synchronization with the Vicon motion capture system. The International Standards for Neurological and Functional Classification of Spinal Cord Injury (ISNCSCI) motor scores of the lower extremities and the Walking Index for Spinal Cord Injury II (WISCI II) score were also assessed to evaluate motor function. The HAL® intervention improved gait speed and cadence during the 10MWT. Before the intervention, both the Gmax and left Quad muscles were not activated. After the intervention, the right Gmax and both Quad muscles were activated in stance phase rhythmically according to the gait cycle. The ISNCSCI motor score also improved from 14 to 16, and the WISCI II scored improved from 7 to 12.

CONCLUSION/CLINICAL RELEVANCE

Our experience with this patient suggests that the HAL® can be an effective tool for improving functional ambulation in patients with chronic spinal cord injury.

A practical approach to the diagnosis of spinal cord lesions

Every neurologist will be familiar with the patient with atypical spinal cord disease and the challenges of taking the diagnosis forward. This is predominantly because of the limited range of possible clinical and investigation findings making most individual features non-specific. The difficulty in obtaining a tissue diagnosis further contributes and patients are often treated empirically based on local prevalence and potential for reversibility. This article focuses on improving the diagnosis of adult non-traumatic, non-compressive spinal cord disorders. It is structured to start with the clinical presentation in order to be of practical use to the clinician. We aim, by combining the onset phenotype with the subsequent course, along with imaging and laboratory features, to improve the diagnostic process.

Surgical ligation of spinal dural arteriovenous fistula

BACKGROUND

Spinal dural arteriovenous fistulas (SDAVFs) are abnormal arteriovenous shunts between a radicular artery and the radicular vein, located in the dorsal surface of the dura sleeve, which drains in a retrograde manner into the coronal venous plexus of the spinal cord without an interposed capillary network. This result is a venous hypertension that reduces spinal cord perfusion and leads to ischemia and edema. Spontaneous resolution is extremely rare and, once symptomatic, the typical course is further progression with increased neurological impairment. Therefore, once a fistula is diagnosed, treatment is recommended.

METHOD

The fistula is placed at the level of intervertebral foramen and surgical ligation is performed through a laminectomy. After dural opening, the area is inspected, and the arterialized vein is identified and ligated.

CONCLUSIONS

Laminectomy and arteriovenous fistula ligation is a safe and reliable approach for accessing and treating spinal dural arteriovenous fistulas.

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.

Angiographic and Clinical Characteristics of Thoracolumbar Spinal Epidural and Dural Arteriovenous Fistulas

BACKGROUND AND PURPOSE

The purpose of this study is to compare the angiographic and clinical characteristics of spinal epidural arteriovenous fistulas (SEAVFs) and spinal dural arteriovenous fistulas (SDAVFs) of the thoracolumbar spine.

METHODS

A total of 168 cases diagnosed as spinal dural or extradural arteriovenous fistulas of the thoracolumbar spine were collected from 31 centers. Angiography and clinical findings, including symptoms, sex, and history of spinal surgery/trauma, were retrospectively reviewed. Angiographic images were evaluated, with a special interest in spinal levels, feeders, shunt points, a shunted epidural pouch and its location, and drainage pattern, by 6 readers to reach a consensus.

RESULTS

The consensus diagnoses by the 6 readers were SDAVFs in 108 cases, SEAVFs in 59 cases, and paravertebral arteriovenous fistulas in 1 case. Twenty-nine of 59 cases (49%) of SEAVFs were incorrectly diagnosed as SDAVFs at the individual centers. The thoracic spine was involved in SDAVFs (87%) more often than SEAVFs (17%). Both types of arteriovenous fistulas were predominant in men (82% and 73%) and frequently showed progressive myelopathy (97% and 92%). A history of spinal injury/surgery was more frequently found in SEAVFs (36%) than in SDAVFs (12%; P=0.001). The shunt points of SDAVFs were medial to the medial interpedicle line in 77%, suggesting that SDAVFs commonly shunt to the bridging vein. All SEAVFs formed an epidural shunted pouch, which was frequently located in the ventral epidural space (88%) and drained into the perimedullary vein (75%), the paravertebral veins (10%), or both (15%).

CONCLUSIONS

SDAVFs and SEAVFs showed similar symptoms and male predominance. SDAVFs frequently involve the thoracic spine and shunt into the bridging vein. SEAVFs frequently involve the lumbar spine and form a shunted pouch in the ventral epidural space draining into the perimedullary vein.

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.

Surgical treatment for spinal dural arteriovenous fistulas: Outcome, complications and prognostic factors

BACKGROUND AND PURPOSE

Spinal dural arteriovenous fistulas (SDAVFs) are rare, acquired pathology and they inevitably lead to severe disability if untreated. The aim of this study is to present the outcome and complications, and to find factors that may affect the outcome after surgical treatment.

METHODS

Seventeen consecutive patients (men - 14, women - 3, age: 41-79) were retrospectively analyzed. The patients presented with paraparesis (88%), bladder symptoms (71%) and/or sensory disturbances (65%). The fistula was found in the upper thoracic spine in 2 cases, in the lower thoracic (T7-Th12) in 11 cases, and in the lumbar spine in 4 cases. Microsurgical shunt interruption was performed in all, followed by epidural arteries coagulation in 12 cases.

RESULTS

In the long term, improvement or achievement of a good stable condition was observed in 13 patients (76%), and no patient deteriorated. All 5 paraplegic patients improved by at least 1 grade in MCS. Satisfactory results (modified McCormick Scale grades I-II) were found in 10 patients (59%), and 15(88%) were independent. Postoperative complications occurred in 4 patients (24%), two of them (12%) required revision surgery for epidural hematoma. The success rate was 94%; one patient required revision surgery for recurrent SDAVF. Better neurological condition on admission (p=0.0098) and age >60 years (p=0.0498) were the factors associated with satisfactory outcome.

CONCLUSIONS

Microsurgical closing of a SDAVF brings good and stable results over time. Aggressive treatment should be attempted even in cases of total loss of spinal cord function. Neurological condition before surgery and age may influence the outcome.

Spinal dural arteriovenous fistula: a case series and review of imaging findings

INTRODUCTION

Spinal dural arteriovenous fistulae (sdAVF) are rare lesions. Patients typically present with slowly progressive myelopathy that is often mistaken for degenerative cervical or lumbar stenosis. On spinal magnetic resonance imaging (MRI), multisegmental T2 hyperintensities along with associated flow voids are pathognomonic of sdAVF. However, diagnosis can be difficult. Definitive diagnosis and localization is achieved with complete spinal angiography. Treatment options include open surgical ligation, endovascular embolization or multimodality treatment. The purpose of this study is to present a series of cases to aid in the assessment, diagnosis and treatment of this unusual pathology.

CASE PRESENTATION

We present 10 cases of sdAVF treated at our center over an 8-year period. Seventy percent of patients were male. The mean age of presentation was 62.6 years. The most common lesion was a dorsal dural AVF with single feeder. All patients underwent open surgical ligation, six having preoperative coil embolization of the radicular artery to allow for intraoperative localization of the fistula. Eight patients showed improvement following treatment as graded by the Nurick system. Two patients failed to improve. None of the patients worsened. One patient had a radiation burn from the spinal angiogram requiring secondary closure and one patient had a pseudomeningocele at the site of surgery that resolved.

DISCUSSION

The successful treatment of sdAVF requires a detailed understanding of clinical presentation and imaging findings to allow for precise treatment. Owing to the rarity of the condition, clinicians must continue to share their experiences to advance our knowledge.

Novalis Stereotactic Radiosurgery for Spinal Dural Arteriovenous Fistula

The spinal dural arteriovenous fistula (SDAVF) is rare, presenting with progressive, insidious symptoms, and inducing spinal cord ischemia and myelopathy, resulting in severe neurological deficits. If physicians have accurate and enough information about vascular anatomy and hemodynamics, they achieve the good results though the surgery or endovascular embolization. However, when selective spinal angiography is unsuccessful due to neurological deficits, surgery and endovascular embolization might be failed because of inadequate information. We describe a patient with a history of vasospasm during spinal angiography, who was successfully treated by spinal stereotactic radiosurgery using Novalis system.

Clinical outcomes following corticosteroid administration in patients with delayed diagnosis of spinal arteriovenous fistulas

Background and purpose

There have been several previously reported cases of acute progression of myelopathic symptoms in patients with spinal arteriovenous fistula (SAVF) treated with intravenous methylprednisolone. This usually occurs during or immediately following steroid administration. We examined a small case series of patients with SAVF treated with epidural, oral, or intravenous steroids to determine the association between steroid administration and clinical outcomes in these patients.

Methods

Following Institutional Review Board approval, we conducted a retrospective review of patients with angiographically-confirmed SAVF who received intravenous, oral, or epidural corticosteroids for treatment of their symptoms. We studied patient-reported motor and sensory function following steroid administration using both the modified Rankin Scale and the Aminoff Motor Disability Scale.

Results

Twenty-one patients with SAVF were included in this study. Thirteen patients (61.9%) had intravenous methylprednisolone administered, four patients (19.0%) had epidural steroid injections, and six patients (28.6%) had oral prednisone. Among patients who received intravenous methylprednisolone, seven (53.8%) reported acute worsening of symptoms during or immediately following steroid administration. Among the patients receiving epidural steroids, none reported worsening and one patient reported short-term relief. Among the patients receiving oral steroids, one reported acute worsening of symptoms. Worsened deficits did not consistently resolve after steroid discontinuation.

Conclusions

Our study suggests that intravenous methylprednisolone can cause immediate worsening of motor and sensory symptoms when administered to patients with SAVF. Steroid administration should be avoided in patients with a myelopathy secondary to an untreated SAVF because neurological worsening may not be fully reversible.

Microscope-assisted endoscopic interlaminar ligation of spinal arteriovenous fistulas: technical note

Spinal dural arteriovenous fistulas (SDAVFs) are the most common type of spinal arteriovenous malformations, and microsurgical ligation is the treatment modality most frequently used for these lesions. Developments in endoscopic techniques have made endoscopy an even less invasive alternative to routine microsurgical approaches in spine surgery, but endoscopic management of SDAVF or other intradural spinal lesions has not been reported to date. The authors describe the use of a microscope-assisted endoscopic interlaminar approach for the ligation of the proximal draining vein of an L-1 SDAVF in a 58-year-old man. A complete cure was confirmed by postoperative angiography. The postoperative course was uneventful, and short-term follow-up showed improvements in the patient's neurological function. The authors conclude that the endoscopic interlaminar approach with microscope assistance is a safe, minimally invasive, innovative technique for the surgical management of SDAVFs in selected patients.

Clinical Outcomes of Patients with Delayed Diagnosis of Spinal Dural Arteriovenous Fistulas

BACKGROUND AND PURPOSE

Spinal dural arteriovenous fistulas are commonly missed on imaging or misdiagnosed as inflammatory or neoplastic processes. We reviewed a consecutive series of spinal dural arteriovenous fistulas referred to our institution that were missed or misdiagnosed on initial imaging and studied the clinical consequences of missing or misdiagnosing the lesion.

MATERIALS AND METHODS

We reviewed spinal dural arteriovenous fistulas diagnosed at our institution between January 1, 2000, and November 1, 2014. A lesion was defined as "misdiagnosed" if initial MR imaging or CT myelography demonstrated characteristic imaging features of spinal dural arteriovenous fistula but the patient was clinically or radiologically misdiagnosed. Outcomes included length of delay of diagnosis, increased disability (increase in mRS or Aminoff motor disability of ≥1 point) between initial imaging evaluation and diagnosis date, and posttreatment disability.

RESULTS

Fifty-three consecutive spinal dural arteriovenous fistulas that were initially misdiagnosed despite having characteristic imaging findings on MR imaging or CT myelography were included in our study. Eight patients (18.9%) underwent spinal angiography before referral, which was interpreted as having negative findings but was either incomplete (6 cases) or retrospectively demonstrated the spinal dural arteriovenous fistulas (2 cases). The median time of delayed diagnosis was 6 months (interquartile range, 2-14 months). Fifty-one patients (96.2%) had increased disability between the initial study, which demonstrated features of a spinal dural arteriovenous fistula, and diagnosis. Thirty-two patients (60.4%) developed a new requirement for a walker or wheelchair. Following treatment, 21 patients (41.2%) had an improvement of 1 point on the mRS or Aminoff motor disability scale.

CONCLUSIONS

Delayed diagnosis of spinal dural arteriovenous fistula with characteristic imaging features results in high rates of additional disability that are often irreversible despite surgical or endovascular treatment of the fistula.

Natural history and treatment of craniocervical junction dural arteriovenous fistulas

Dural arteriovenous fistulas (DAVFs) located at the craniocervical junction are rare vascular malformations with distinctive features, and their natural history and the optimal treatment strategy remains unclear. We retrospectively reviewed eight patients with craniocervical junction DAVF who were evaluated at our institution between 2009 and 2012. We also conducted a MEDLINE search for all reports of craniocervical junction DAVF between 1970 and 2013, and reviewed 119 patients from 56 studies. From a total of 127 patients, 46 (37.1%) presented with myelopathy, 53 (43.1%) with subarachnoid hemorrhage (SAH), and four (3.3%) with brainstem dysfunction. SAH was typically mild, most often Hunt and Hess Grade I or II (83.3%), and associated with ascending venous drainage via the intracranial veins (p<0.001). Higher rates of obliteration were observed after microsurgery compared to embolization. Overall, younger age (odds ratio [OR] 1.07; 95% confidence interval [CI] 1.01-1.12; p=0.011), hemorrhagic presentation (OR 0.17; 95% CI 0.06-0.50; p=0.001), and microsurgery (OR 0.23; 95% CI 0.08-0.6; p=0.004) were independently predictive of good outcome at the last follow-up. Microsurgery was the only independent predictor of overall improvement at the last follow-up (OR 4.35; 95% CI 1.44-13.2; p=0.009). Prompt diagnosis and microsurgical management, offering a greater chance of immediate obliteration, may optimize the outcomes for patients with craniocervical junction DAVF. Endovascular treatment is often not feasible due to lesion angioarchitecture, and is associated with a higher risk of lesion recanalization or recurrence. However, long term studies with newer embolic agents such as Onyx (ev3 Endovascular, Plymouth, MN, USA) are yet to be performed.

Spinal Dural Arteriovenous Fistula Presenting as a Recurrent Nucleus Pulposus Herniation: A Case Report and Literature Review

CASE

Of the many potential causes of nerve compression that lead to radiculopathy, vascular etiologies remain among the most infrequent, with an estimated prevalence of only five to ten per million cases of radiculopathy. In this case report, we outline the clinical presentation, imaging, intraoperative findings, and pathologic findings for a fifty-four-year old patient with an intradural, extramedullary form of a spinal dural arteriovenous fistula at the L1-L2 level who presented only with axial back pain and radiculopathy. The radiologist and surgeon initially diagnosed the patient with a herniated nucleus pulposus. However, the intraoperative findings and angiogram were suggestive of an arteriovenous fistula. Methods to identify this rare entity are described for the orthopaedic spine community.

CONCLUSION

The potential for a missed diagnosis is particularly important as many partial discectomy procedures are performed at small surgical centers with limited blood products available and no vascular surgeon on staff. For patients with preoperative magnetic resonance imaging (MRI) that is suggestive of vascular malformations (T2 hyperintensity in the lower spinal cord and conus medullaris), we recommend that MR angiography be performed as a secondary diagnostic evaluation. MR angiography has a 95% positive predictive value for specifically diagnosing an arteriovenous fistula.

Lower urinary tract dysfunction in patients with peripheral nervous system lesions

The prevalence of lower urinary tract (LUT) dysfunction in peripheral nervous system (PNS) disorders is larger than in comparable control populations. This is particularly true for polyneuropathies with autonomic nervous system involvement, and for localized lesions with LUT innervation. LUT symptoms may be the guide to the diagnosis of processes localized in the lumbosacral spinal canal (as in cauda equina syndrome), and in the pelvis. Typical LUT dysfunctions (LUTD) caused by PNS involvement include bladder and sphincter hypoactivity with poor emptying, and incontinence. Paradoxically, bladder overactivity may also occur in pure PNS lesions. The acute cauda equina syndrome is an emergency requiring magnetic resonance imaging and surgery; in chronic neurogenic LUTD due to PNS involvement, the diagnosis of the lesion may be clarified by clinical neurophysiologic testing. Other important causes of neurogenic LUT dysfunction are perineoabdominal and pelvic surgeries. Surgeons are devising nerve-sparing techniques to prevent such major and often persistent complications in patients who are otherwise cured of the underlying disease. LUTD significantly affects the quality of life in patients and may lead to recurring urinary infections and upper urinary tract involvement. Thorough assessment of LUT function by urodynamics may be necessary in patients who are not improved by simple conservative measures.

Sexual dysfunction in patients with peripheral nervous system lesions

Peripheral nervous system (PNS) disorders may cause sexual dysfunction (SD) in patients of both genders. These disorders include mainly polyneuropathies (particularly those affecting the autonomic nervous system (ANS)) and localized lesions affecting the innervation of genital organs. Impaired neural control may produce a malfunction of the genital response consisting of loss of genital sensitivity, erectile dysfunction, loss of vaginal lubrication, ejaculation disorder, and orgasmic disorder. In addition, there is often a loss of desire which actually has a complex pathogenesis, which goes beyond the mere loss of relevant nerve function. In patients who have no manifest health problems - particularly men with erectile dysfunction - one should always consider the possibility of an underlying polyneuropathy; in patients with SD after suspected denervation lesions of the innervation of genital organs within the lumbosacral spinal canal and in the pelvis, clinical neurophysiologic testing may clarify the PNS involvement. SD can alter self-esteem and lower patients' quality of life; opening up a discussion on sexual issues should be a part of the management of patients with PNS disorders. They may greatly benefit from counseling, education on coping strategies, and specific treatments.

Value of prominent flow voids without cord edema in the detection of spinal arteriovenous fistulae

PURPOSE

To determine the prevalence of spinal dural arteriovenous fistulae (SDAVF) in patients presenting with prominent vascular flow voids on imaging without other imaging findings suggestive of SDAVF.

METHODS

We retrospectively identified patients from January 1, 2005 to March 1, 2012 who underwent spinal angiography for suspected SDAVF with prominent vascular flow voids on prior imaging. We excluded patients with other major spinal pathology or other imaging findings of SDAVF including cord hyperintensity, enhancement, or expansion. We calculated the proportion of patients with positive findings for SDAVF on angiography and evaluated the prevalence of SDAVF for this finding alone and in correlation with clinical findings.

RESULTS

18 patients underwent spinal angiography for prominent flow voids on imaging without other spinal pathology or imaging findings of SDAVF. Three had a SDAVF detected on angiography. The prevalence of SDAVF in this population was low, only 17% (95% CI 6-39%). All of the patients with positive angiography findings had myelopathy, increasing the prevalence to 100% if the additional clinical finding of myelopathy was present.

CONCLUSIONS

Prominent flow voids without other imaging findings suggestive of SDAVF is poorly predictive of the presence of a SDAVF, unless myelopathy is present clinically.