Epidural Arteriovenous Fistulas Research Articles

Spinal Arteriovenous Vascular Malformations in Patients with Neural Tube Defects.

Neural tube defects, such as tethered cord, intradural lipoma, or myelomeningocele may coexist with spinal vascular malformations. The coexistence of these 2 rare entities is suggestive of a causal relationship between them, which may lead to further understanding of their pathogenesis. We present a series of 6 patients with epidural spinal arteriovenous fistulas associated with neural tube defects. We retrieved cases of spinal vascular malformations associated with neural tube defects seen at our institution. The clinical presentation, MR imaging/MRA and angiographic imaging, treatment outcomes, and long-term neurologic outcomes were analyzed. Descriptive statistical analyses are reported. Six patients with epidural arteriovenous fistulas and neural tube defects were included in this study. The mean age at presentation was 42 years, and the most common presenting symptoms were lower extremity weakness followed by sensory disturbances and bladder/bowel dysfunction. In most cases (5/6), the fistulas were located at the sacral level. All cases were fed by the lateral sacral artery (6/6). Four patients had prior spine surgery, but the fistula was in the operative bed in 2 cases. All fistulas were extradural with secondary intradural venous drainage. Five patients underwent transarterial embolization with Onyx, and 1 patient had a treatment-related complication. It is conceivable that there is a pathophysiologic link between neural tube defects and development of spinal vascular malformations. Delayed neurologic deterioration or high conus signal in a patient with a neural tube defect should suggest the possibility of such an association.

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

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. 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. 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%). 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.

Angioarchitecture of arteriovenous fistulas at the craniocervical junction: a multicenter cohort study of 54 patients.

OBJECTIVE The aim of this retrospective multicenter cohort study was to assess the details of the angioarchitecture of arteriovenous fistulas (AVFs) at the craniocervical junction (CCJ) and to determine the associations between the angiographic characteristics and the clinical presentations and outcomes. METHODS The authors analyzed angiographic and clinical data for patients with CCJ AVFs from 20 participating centers that are members of the Japanese Society for Neuroendovascular Therapy (JSNET). Angiographic findings (feeding artery, location of AV shunt, draining vein) and patient data (age, sex, presentation, treatment modality, outcome) were tabulated and stratified based on the angiographic types of the lesions, as diagnosed by a member of the CCJ AVF study group, which consisted of a panel of 6 neurointerventionalists and 1 spine neurosurgeon. RESULTS The study included 54 patients (median age 65 years, interquartile range 61-75 years) with a total of 59 lesions. Five angiographic types were found among the 59 lesions: Type 1, dural AVF (22 [37%] of 59); Type 2, radicular AVF (17 [29%] of 59); Type 3, epidural AVF (EDAVF) with pial feeders (8 [14%] of 59); Type 4, EDAVF (6 [10%] of 59); and Type 5, perimedullary AVF (6 [10%] of 59). In almost all lesions (98%), AV shunts were fed by radiculomeningeal arteries from the vertebral artery that drained into intradural or epidural veins through AV shunts on the dura mater, on the spinal nerves, in the epidural space, or on the spinal cord. In more than half of the lesions (63%), the AV shunts were also fed by a spinal pial artery from the anterior spinal artery (ASA) and/or the lateral spinal artery. The data also showed that the angiographic characteristics associated with hemorrhagic presentations-the most common presentation of the lesions (73%)-were the inclusion of the ASA as a feeder, the presence of aneurysmal dilatation on the feeder, and CCJ AVF Type 2 (radicular AVF). Treatment outcomes differed among the angiographic types of the lesions. CONCLUSIONS Craniocervical junction AVFs commonly present with hemorrhage and are frequently fed by both radiculomeningeal and spinal pial arteries. The AV shunt develops along the C-1 or C-2 nerve roots and can be located on the spinal cord, on the spinal nerves, and/or on the inner or outer surface of the dura mater.

Analysis of 30 Spinal Angiograms Falsely Reported as Normal in 18 Patients with Subsequently Documented Spinal Vascular Malformations.

The early diagnosis of spinal vascular malformations suffers from the nonspecificity of their clinical and radiologic presentations. Spinal angiography requires a methodical approach to offer a high diagnostic yield. The prospect of false-negative studies is particularly distressing when addressing conditions with a narrow therapeutic window. The purpose of this study was to identify factors leading to missed findings or inadequate studies in patients with spinal vascular malformations. The clinical records, laboratory findings, and imaging features of 18 patients with spinal arteriovenous fistulas and at least 1 prior angiogram read as normal were reviewed. The clinical status was evaluated before and after treatment by using the Aminoff-Logue Disability Scale. Eighteen patients with 19 lesions underwent a total of 30 negative spinal angiograms. The lesions included 9 epidural arteriovenous fistulas, 8 dural arteriovenous fistulas, and 2 perimedullary arteriovenous fistulas. Seventeen patients underwent endovascular (11) or surgical (6) treatment, with a delay ranging between 1 week and 32 months; the Aminoff-Logue score improved in 13 (76.5%). The following factors were identified as the causes of the inadequate results: 1) lesion angiographically documented but not identified (55.6%); 2) region of interest not documented (29.6%); or 3) level investigated but injection technically inadequate (14.8%). All the angiograms falsely reported as normal were caused by correctible, operator-dependent factors. The nonrecognition of documented lesions was the most common cause of error. The potential for false-negative studies should be reduced by the adoption of rigorous technical and training standards and by second opinion reviews.

A New Type of Spinal Epidural Arteriovenous Fistulas Causes Spinal Epidural Hemorrhage: An Analysis of Five Cases and Natural History Consideration.

Spinal epidural arteriovenous fistulas (SEDAVFs) are peculiar and poorly understood lesions with a poorly understood natural history. They usually are subclassified into 2 types according to their drainage components. This study aimed to describe a new type ofSEDAVFs that is featured with a unique drainage pattern and present our natural history hypothesis of SEDAVFs. Five SEDAVF cases of the new type werereviewed retrospectively from a high case-volume spinal vascular malformation database. The clinical manifestations, neuroradiologic findings, angioarchitecture, treatment strategies, and clinical outcomes were assessed. All patients presented with spontaneous spinal epidural hematoma, and 2 of them exhibited rebleeding. The median age at the initial episode was 20 years. Spinal digital subtraction angiography revealed slow-flow epidural fistulas drained by spinal epidural venous plexus without intradural drainage or engorged venous pouches in all 5 patients. Three patients underwent microsurgical treatment. The outcomes of all of the patients were favorable. Our study reported a special type of hemorrhagic SEDAVF without an intradural drainage component or epidural mass effect. The key diagnostic clue was early opacification of spinal epidural venous plexus on spinal angiogram. We believe SEDAVFs may form at an early age and gradually develop with time. Different types of SEDAVFs may represent different developing stages of one disease, and our type may represent the early stage of SEDAVFs.

Clinical presentation and treatment outcomes of spinal epidural arteriovenous fistulas.

OBJECTIVE Spinal epidural arteriovenous fistulas (SEDAVFs) constitute a rare but treatable cause of vascular myelopathy and are a different subtype from the more common Type I spinal dural AVFs. The purpose of this study was to review a consecutive series of SEDAVFs from a single institution and report on the clinical presentations, functional status, and treatment outcomes. METHODS The authors identified all SEDAVFs treated at their institution from 2005 to 2015. SEDAVFs were defined as spinal AVFs in which the fistulous connection occurred in the epidural venous plexus. The clinical presentation, functional status, immediate treatment outcomes, and long-term neurological outcomes were analyzed. RESULTS Twenty-four patients with SEDAVFs were included in this study. The patients' mean age at presentation was 66.9 years. The most common presenting symptoms were pain and numbness (22 patients, 91.7%), followed by lower-extremity weakness (21 patients, 87.5%). The mean duration of symptoms prior to diagnosis was 11.8 months. Eighteen patients (75.0%) were treated with endovascular therapy alone, 4 (16.7) with surgery, and 2 (8.3%) with a combination of techniques. There was 1 major treatment-related complication (4.2%). Fifteen patients (62.5%) had improvement in disability, and 12 patients (54.5%) had improvement in sensory symptoms. CONCLUSIONS SEDAVFs often present with lower-extremity motor dysfunction and sensory symptoms. With the availability of newer liquid embolic agents, these lesions can be effectively treated with endovascular techniques. Surgery is also effective at treating these lesions, especially in situations where endovascular embolization fails or is not safe and in patients presenting with mass effect from compressive varices.

Distinct Radioanatomic Features and Treatments for Spinal Epidural Arteriovenous Fistulae

Spinal epidural arteriovenous fistula (SEDAVF) is a novel clinical entity that is distinct from spinal dural arterovenous fistula, although both diseases manifest as venous congestive myelopathy. We reviewed nine cases of SEDAVF to elucidate its pathogenesis and radioanatomic features and to optimize treatment strategy. All cases exhibited similar angioarchitecture, with a single shunt at the epidural venous plexus that drains into the intradural perimedullary vein and connects to the ventral spinal vein. Interestingly, all lesions were located on the ventral side of the lower lumber and sacral region, and shunts were located ventrally in association with the epidural pouch suspected to be isolated as extradural venous lake. This may be the result of the specificity of the feeding artery and a congenital shift in the distribution of the venous drainage system at the terminal film and conus. We explored two options for the treatment for SEADF: endovascular transarterial embolization and surgical shunt interruption. Among our patients, three were treated using the endovascular approach and six were treated with surgery. While both treatments were effective at improving symptoms, the delay between disease onset and diagnosis precluded a complete cure. Early diagnosis and adequate treatment based on precise knowledge of the angioarchitecture and pathogensis of SEDAVF is essential for improved outcomes.

Spontaneous Spinal Epidural Hematoma: A Study of 55 Cases Focused on the Etiology and Treatment Strategy

Spontaneous spinal epidural hematoma (SSEH) is a rare neurologic emergency of the spinal cord. Its cause and treatment strategy remain controversial. This study aimed to evaluate a significant cause of SSEH and to discuss the treatment strategy according to the clinical outcomes of patients in 2 institutions. Fifty-five cases of SSEH treated at our institutions between February 2002 and February 2016 were retrospectively analyzed. The mean age of the first SSEH onset was 31.8 years. The follow-up rate was 72.7%, with 28 patients (70%) showing satisfactory clinical outcomes. Forty patients received preoperative spinal digital subtraction angiography. Spinal epidural (extradural) arteriovenous fistula was detected in 6 patients (15%), 5 of whom showed 1 type of special slow-flow shunt. Nineteen patients (34.5%) suffered from multiple episodes until they underwent invasive treatments or last follow-up. Rebleeding was confirmed in 8 patients. None of the patients had a subsequent episode or rebleeding after invasive treatment. The risk factors for poor clinical outcome included advanced age at initial onset (P= 0.020), a short progression interval (P= 0.030), no symptom relief after admission (P= 0.011), hypesthesia (P= 0.017), complete spinal cord injury (P= 0.001), and hematoma below the T4 level (P= 0.014). Spinal epidural (extradural) arteriovenous fistula is a significant cause of SSEH. Standard spinal digital subtraction angiography is necessary for patients with SSEH. Conservative treatment could not prevent occurrence of multiple episodes or rebleeding in patients. Microsurgery should be recommended as the preferred treatment strategy for SSEH. Endovascular embolization is also recommended if applicable.

First-Pass Contrast-Enhanced MRA for Pretherapeutic Diagnosis of Spinal Epidural Arteriovenous Fistulas with Intradural Venous Reflux.

Spinal epidural AVFs are rare spinal vascular malformations. When there is associated intradural venous reflux, they may mimic the more common spinal dural AVFs. Correct diagnosis and localization before conventional angiography is beneficial to facilitate treatment. We hypothesize that first-pass contrast-enhanced MRA can diagnose and localize spinal epidural AVFs with intradural venous reflux and distinguish them from other spinal AVFs. Forty-two consecutive patients with a clinical and/or radiologic suspicion of spinal AVF underwent MR imaging, first-pass contrast-enhanced MRA, and DSA at a single institute (2000-2015). MR imaging/MRA and DSA studies were reviewed by 2 independent blinded observers. DSA was used as the reference standard. On MRA, all 7 spinal epidural AVFs with intradural venous reflux were correctly diagnosed and localized with no interobserver disagreement. The key diagnostic feature was arterialized filling of an epidural venous pouch with a refluxing radicular vein arising from the arterialized epidural venous system. First-pass contrast-enhanced MRA is a reliable and useful technique for the initial diagnosis and localization of spinal epidural AVFs with intradural venous reflux and can distinguish these lesions from other spinal AVFs.

Minimally invasive approach for the treatment of lumbar epidural arteriovenous fistulas with intradural venous reflux

BackgroundVascular lesions of the spinal cord are increasingly recognized. The most common types of these lesions are dural arteriovenous fistulas (AVFs) whereas, extradural AVFs are a very rare type of spinal AVF and can be associated with either extradural or intradural venous reflux. This results in neurological deficits through congestive or compressive myeloradiculopathy. These lesions must be treated to allow stabilization or improvement of neurologic status, either by endovascular therapy or microsurgical interruption. However, because some patients are not amenable to endovascular treatment, surgery is often warranted, which usually involves hemi- or bilateral laminectomy following a midline approach with bilateral muscle stripping. The main drawback of this procedure is directly related to the morbidity of the approach. Although, minimally invasive approaches are likely to overcome this drawback, there is a lack of reported experience supporting their use for treating spinal dural AVFs. Case presentationTwo patients, aged 62 and 79 years old, presented with rapidly progressive myelopathy characterized by paraparesis and sphincter disturbance. Spinal magnetic resonance imaging showed spinal cord oedema with perimedullary flow voids in both cases. Digital subtraction angiography revealed extradural AVFs associated with perimedullary venous reflux. Endovascular therapy was not feasible. Both patients were treated with microsurgical interruption of the intradural vein through a non-expendable retractor. Complete exclusion was confirmed on postoperative angiography, resulting in resolution of spinal cord edema and improved neurological functional status at 2-year follow-up. ConclusionThe minimally invasive surgical treatment of spinal AVFs with epidural venous reflux is safe and effective. This approach is a valuable alternative to endovascular therapy and the standard open microsurgical approach.

Spontaneous Resolution of a High-Flow Congenital Spinal Epidural Arteriovenous Fistula in a Pediatric Patient

The spontaneous resolution of a spinal vascular malformation is a rare phenomenon. We report the case of a 19-month-old male infant with a high-flow congenital spinal epidural arteriovenous fistula that completely regressed between the time of diagnostic angiography and planned endovascular treatment. Prior reported instances, potential underlying mechanisms, and implications for management timing and necessity are discussed.

Pediatric spinal arteriovenous malformations and fistulas: a single institute’s experience

Pediatric spinal vascular diseases are extremely rare. We aimed to evaluate their clinical characteristics and treatment outcomes in our institute. A total of 10 patient files were retrospectively reviewed, including 3 cases of intramedullary arteriovenous malformations (AVMs), 6 cases of perimedullary arteriovenous fistulas (AVFs), and 1 case of epidural AVF. Clinical features, radiological findings, treatment results, and clinical outcomes were evaluated. The median durations of the radiologic and clinical follow-ups were 17.7 and 107.9months, respectively. The male to female ratio was 1:1, with a median age at diagnosis of 9years. All AVMs were juvenile type, all perimedullary AVFs were high flow types (three type IVb and three type IVc), and one epidural AVF was associated with intradural venous drainage. Most cases (90%) were located in the cervical spine and conus medullaris. Acute neurological deterioration was identified in five patients; however, bleeding was identified in only one patient. Two cases were surgically treated, seven cases underwent embolization, and one case underwent radiosurgery. Three cases were completely obliterated, and their clinical states were improved (n=2; 66.7%) and stationary (n=1; 33.3%). Meanwhile, seven cases were incompletely obliterated, and their clinical states were improved (n=2; 28.6%), stationary (n=3; 42.8%), and aggravated (n=2; 28.6%). Pediatric spinal AVMs and AVFs were mostly complex and high flow types, and complete obliteration could not be satisfactorily achieved. Incompletely treated lesions should be closely followed up because they may worsen.

MRI findings of spinal arteriovenous fistulas: focusing on localisation of fistulas and differentiation between spinal dural and perimedullary arteriovenous fistulas

To investigate the magnetic resonance imaging (MRI) findings of spinal arteriovenous fistulas (AVFs) to predict their locations and types. Patients who underwent spinal angiography for suspected spinal AVF between April 2003 and April 2013 were enrolled. Spine MRI images were analysed by two radiologists in consensus focusing on the distribution patterns of flow void pial vessels (FVPVs): longitudinal distribution pattern along the spinal level (even or uneven, with description of the most crowded level in uneven cases) and axial distribution pattern in relation to the cord (ventral, dorsal, or co-dominance). Spinal angiography served as the reference standard for the locations and types of fistulas. Thirty-two patients (M:F=24:8, mean age, 53 years; range, 2-74 years) were included. There were 18 patients with spinal dural AVFs (SDAVFs), seven with perimedullary AVFs, four with epidural AVFs, and three diagnosed as normal. In 12 of 15 longitudinally uneven AVFs, the most crowded levels of FVPVs corresponded to the true fistulous levels within two-level differences. While dorsal dominance was predominant in SDAVFs (13/18), ventral dominance was predominant in perimedullary AVFs (5/7; p<0.01). Fistulous levels may be predicted to be within two levels of the most crowded levels of FVPVs. The dorsal dominance pattern of FVPVs favours SDAVFs, whereas ventral dominance suggests perimedullary AVFs.

Bilateral and symmetric isolated dorsospinal arteries with prominent anterior radiculomedullary contribution

We present the case of a 15-year-old girl with a left T7 spinal epidural arteriovenous fistula (SEAVF), in whom bilateral and symmetric isolated T9 dorsospinal arteries (DAs) were incidentally documented,...

Neuro-Interventions for the Neonates with Brain Arteriovenous Fistulas: With Special Reference to Access Routes.

Neonatal neuro-intervention is challenging. The purpose of this article is to report the neuro-intervention for the neonates with brain arteriovenous fistulas (AVFs), with special reference to access routes. Fifteen neonates (12 boys and 3 girls) who underwent neuro-intervention within the first 14 days of life were included. Their diagnoses included vein of Galen aneurysmal malformation (6), dural sinus malformations with arteriovenous (AV) shunts (6), pial AVF (2), and epidural AVF (1). Birth weight ranged from 1,538 g to 3,778 g (mean 2,525 g). Neuro-interventions, especially access routes, in the neonatal periods (< 1 month) were retrospectively reviewed. All neonates presented with severe cardiac failure. In total, 29 interventions (mean 1.9) were performed within 1 month. Although 12 neonates with birth weight more than 2,700 g could be treated through transfemoral arterial routes, 3 neonates with birth weight less than 2,200 g could not be treated successfully by femoral arterial routes. Interventions were performed through 19 femoral arterial, 3 femoral venous, 2 umbilical arterial, 3 umbilical venous, 3 transcardiac, and 2 direct carotid routes. Their overall outcomes were six good recovery, one moderate disability, two severe disabilities, one vegetative state, and five deaths with a mean follow-up period of 7 years 2 months. Neuro-intervention for the neonates with birth weight more than 2,700 g can be performed by femoral arterial routes using a 4F sheath. For those with birth weight less than 2,200 g, however, alternative access routes are required.

Normal Venous Phase Documented during Angiography in Patients with Spinal Vascular Malformations: Incidence and Clinical Implications.

A key angiographic sign observed in patients with spinal vascular malformations is the absence of a normal venous phase. While this finding alone is often believed to rule out a lesion impacting the perimedullary venous drainage, the observation of a venous phase in several patients with vascular malformations led us to reconsider the validity of that sign. Eighty-one patients with 6 spinal arteriovenous malformations, 16 perimedullary arteriovenous fistulas, 61 spinal epidural or dural AVFs, and 1 paravertebral AVF (2 patients had multiple lesions) were reviewed. The venous phase was defined as normal, absent, or indeterminate. The venous phase timing was analyzed in patients with spinal dural or epidural AVFs. The existence of a venous phase could not be determined for technical reasons in 23 patients. A venous phase was documented in 25 of 58 patients (43%), including 16 of 49 vascular malformations (40.0%) with perimedullary venous drainage. Twelve of the 30 patients (40.0%) with dural or epidural AVFs had a normal venous phase, appearing, on average, 10.1 seconds and best visualized 15.0 seconds after opacification of the artery of Adamkiewicz. A normal venous phase was observed in 43% of patients with spinal vascular malformations, and within an acceptable delay (<18 seconds) in 40% of slow-flow AVFs. While it remains an important angiographic sign, the observation of a normal venous phase cannot be used to exclude the presence of a vascular malformation or justify interrupting a diagnostic spinal angiogram.

Lumbar spinal epidural arteriovenous fistula with perimedullary venous drainage after endoscopic lumbar surgery.

Spinal epidural arteriovenous fistulas (AVFs) with perimedullary venous drainage are rare. This report describes a case of lumbar epidural AVF in a patient with a history of endoscopic lumbar discectomy at the same level 8 years prior to presenting with progressive myelopathy secondary to retrograde venous reflux into the perimedullary vein. A 69-year-old man presented with progressive lower extremity weakness and sensory disturbance and loss of sphincter control 8 years after endoscopic lumbar discectomy for a disc herniation at L4-5 level. Magnetic resonance imaging showed spinal cord edema and dilated intradural perimedullary vessels. Spinal angiography revealed an epidural AVF at the site of the previous endoscopic lumbar surgery with intradural perimedullary venous drainage. The fistula was successfully occluded via endovascular transarterial embolization, and the patient had stabilization of his neurological deficits. Lumbar spinal epidural AVFs, especially those associated with iatrogenic trauma, are rare. Endoscopic surgical procedure can occlude the epidural venous plexus and disturb venous drainage, thereby inducing local venous hypertension and leading to epidural AVF with perimedullary venous drainage. This type of pathology should be considered within the differential diagnosis of delayed neurological deterioration after spinal surgery.

Angiographic suppression of the artery of Adamkiewicz by venous hypertension resolving after embolization in a case of spinal epidural arteriovenous fistula

A case of complete angiographic suppression of the artery of Adamkiewicz and anterior spinal artery in a patient with a spinal epidural arteriovenous fistula (AVF) is reported. Slow flow AVFs...

Triaxial system により経動脈的塞栓術を行った腰部spinal ventral epidural arteriovenous fistula の1 例

【目的】Triaxial system により経動脈的塞栓術を行った腰部spinal ventral epidural arteriovenous fistula 症例を報告する．【症例】78 歳男性．緩徐進行性の下肢対麻痺，膀胱直腸障害で発症した．第3 腰椎左腹側硬膜外静脈叢への動静脈shunt による鬱血性脊髄障害であった．Feeder は左右第3 腰動脈から分岐するdorsal somatic branch で，shunt 存在部位と対側の血流が優位であった．Triaxial system で右第3 腰動脈からretrocorporeal anastomosis を介した塞栓術を施行し，shunt の完全閉塞を得た．【結論】脊髄症例においてもtriaxial system により，マイクロカテーテルを安全，確実に目的部位に到達させ，有効な治療を行うことが可能である．

Spinal Dural Arteriovenous Fistulas Supplied from Multiple Segmental Arteries: Microsurgery Using Indocyanine Green Angiography and Radiosurgery with a Spine Tracking System

Endovascular occlusion and/or surgical disconnection are the first treatment of choice for spinal dural arteriovenous fistulas (d-AVFs) with venous flow reversal into the perimedullary veins. However, d-AVFs with multiple feeding arteries and fistula points are associated with various difficulties related with treatment. We herein describe three cases of AVFs supplied from multiple segmental arteries treated with surgery using indocyanine green (ICG) angiography or radiosurgery using a spine tracking system. ICG was administered via intravenous injection during and after the surgical disconnection procedures. As double d-AVFs or multi-segmental ventral epidural type AVFs require invasive spinal surgery, less invasive radiosurgery was performed using a CyberKnife with a spine tracking system. ICG angiography revealed changes in venous flow reversal during the surgical maneuvers as well as the disappearance of the AVF after disconnecting all draining veins in Case 1. Among the patients with double AVFs or multi-segmental ventral epidural type AVFs treated with radiosurgery, the fistula points received a marginal dose of 15 to 18 Gy at an isodose of 60% to 67%. The AVFs disappeared or almost disappeared on angiography one year after radiosurgery in Case 2. The signal void on T2-weighted images showing a venous pouch disappeared, the draining veins normalized, and the cord compression was alleviated two years after radiosurgery in Case 3. No episodes of recurrence were noted in any of the patients four to seven years after treatment. ICG angiography plays an important role in obtaining a complete disconnection of the draining veins during complex AVF surgery. Radiosurgery is indicated for spinal d-AVFs with multiple feeding arteries and fistulas in patients without progressive symptoms.