Asymptomatic spinal dural arteriovenous fistulas: pathomechanical considerations

Clinical presentation and treatment of 26 spinal epidural arteriovenous fistulas: a single-center experience

BACKGROUND

Spinal epidural arteriovenous fistulas (SEDAVFs) are rarely diagnosed vascular malformations that can cause spinal cord compression and congestive myelopathy.

METHODS

This is a single-center, retrospective case series of patients with SEDAVFs who underwent observation or treatment at UCLA medical center between 1993 and 2023.

RESULTS

Between 1993 and 2023 a total of 26 patients at UCLA were found to have a SEDAVF. The median age at treatment was 59 years (range 4 months to 91 years). Compared with sacral, lumbar, and thoracic SEDAVFs, patients with cervical SEDAVF were younger (41 years vs 63 years, P=0.016) and more likely to be female (66.7% vs 14.3%, P=0.006). Possible triggers for development of SEDAVFs may be prior spinal surgery or trauma (n=4), turning the neck (n=1), lifting a heavy box (n=1), a prolonged period of bending over (n=1), and neurofibromatosis type 1 (n=1). Of the 22 patients treated endovascularly, 18 (82%) were angiographically cured on the first attempt without complications. One patient underwent surgical treatment alone and had a failed surgery on the first attempt, and developed a surgical site infection after the second successful attempt at treatment. Of the 16 patients with adequate clinical follow-up, 11 (69%) demonstrated early improved clinical outcome (eg, improved strength on examination, absent bruit).

CONCLUSIONS

SEDAVFs are a rarely diagnosed disease that can be treated effectively and safely with endovascular embolization in most cases. Patients with sacral, lumbar, and thoracic SEDAVFs were older and more often male compared to patients with cervical SEDAVFs.

Dural arteriovenous fistulas at the craniocervical junction: a systematic review and meta-analysis

BACKGROUND

The management for craniocervical junction dural arteriovenous fistulas (CCJ-DAVFs) remains controversial and clinically challenging. We systemically summarized the clinical and angiographic outcomes of microsurgery, embolization, and conservative management.

METHODS

Relevant articles were retrieved from PubMed, Scopus, Web of Science, and Cochrane, following PRISMA guidelines. A systematic review and meta-analysis were conducted on the clinical characteristics, management approaches, and clinical and angiographic outcomes.

RESULTS

We included 13 articles (166 patients). The weighted mean age was 58.9 years (95%CI: 53.2-64.5), 58.8 years (95%CI: 48.4-69.2), and 63.8 years (95%CI: 60.1-67.5), in microsurgery, embolization, and conservative groups respectively, with an overall male sex predominance (microsurgery [n = 51/77, 66.2%], embolization [n = 44/56, 78.6%], and conservative management [n = 6/8, 75.0%]). Patients were managed with microsurgery (n = 80/172, 46.5%), embolization (n = 79/172, 45.9%), and conservative treatment (n = 13/172, 7.6%). Foramen magnum was the most common location (microsurgery [n = 34/77, 44.2%], embolization [n = 31/56, 55.4%], and conservative treatment [n = 3/8, 37.5%]). Vertebral artery was the primary feeder (microsurgery [n = 58/84, 69.1%], embolization [n = 41/86, 47.6%], and conservative treatment [n = 4/7, 57.1%]). Complete fistula obliteration rates were 74.1% (95%CI:52.3-88.2%) in the microsurgery group and 54.9% (95%CI:30.7-77.0%) in the embolization group. Complications rates were 16.2% (95%CI:6.7-34.5%) in the embolization group, 11.6% (95%CI:3.8-30.4%) in the microsurgery group, and 7.7% (95%CI:1.1-39.1%) in the conservative group. Different rates of good clinical outcomes were observed [microsurgery: 66.4% (95%CI:48.1-80.8%), embolization: 51.9% (95%CI:30.8-72.4%), and conservative: 11.6% (95%CI:4.4-27.4%)].

CONCLUSIONS

In patients with CCJ-DAVFs, each management approach has its own merits based on the fistula and patient characteristics.

A Novel Rat Model of Venous Hypertensive Myelopathy Produced by Arteriovenous Bypass Plus Venous Stenosis

BACKGROUND AND OBJECTIVES

Venous hypertensive myelopathy (VHM), mainly induced by the spinal dural arteriovenous fistula, is a congestive spinal cord injury that currently has no appropriate animal model available in preclinical research.

METHODS

Sprague Dawley rats (280-320 g) were used. The rats were divided into 3 groups: (1) Group 1, which underwent renal artery-dorsal spinal venous bypass (AVB group); (2) Group 2, which underwent renal artery-dorsal spinal venous bypass and drainage vein stenosis (AVB/VS group); and (3) Control group, with T13 dorsal vein ligation. The success of the model was assessed using Doppler ultrasound and 7.0-T magnetic resonance imaging. Transmission electron microscopy, histochemistry, proteomics, and western blot analysis were used to evaluate ultrastructural, pathological, and molecular features in the spinal cord and cerebrospinal fluid (CSF).

RESULTS

The success rate of the arteriovenous bypass was 100% at 5 days and 83% at 2 weeks. The locomotor assessment showed decreased lower extremity strength in the AVB/VS group ( P = .0067), whereas unremarkable changes were found in the AVB and Control groups. Histochemical staining suggested a 2-fold expansion of the dorsal spinal vein in the AVB/VS group, which was lower than that in the AVB group ( P < .05); however, the former displayed greater myelin and neuronal damage ( P < .05) and slight dilatation of the central canal ( P > .05). Proteomics analysis revealed that the complement and coagulation cascade pathways were upregulated in the CSF of AVB/VS rats, whereas the C3 level was elevated both in the CSF and bilateral spinal cord. Furthermore, overexpression of C3, ITGB2, and CD9 in the spinal cord was confirmed by immunoblotting.

CONCLUSION

These findings suggest that the AVB/VS model can effectively mimic the clinical and molecular characteristics of VHM. Furthermore, they suggest that impaired deep intramedullary venous drainage is the key reason for the VHM.

Vascular loops mimicking herniated lumbar discs: fair warning

The authors report their experience with twenty-one consecutive patients who presented with symptoms and imaging characteristics of a herniated lumbar disc; of whom, at the time of surgery had a vascular loop instead. The procedure was performed on 14 women and seven men with a mean age of 39 years. Clinical complaints included lumbar aching with one limb overt radiculopathy in all patients; with additional sphincter dysfunction in two cases. Symptoms had developed within a mean period of three months. In all patients, the disc was exposed through an L5-S1 (n = 10); L4-L5 (n = 5) and L3-L4 (n = 6) open minimal laminotomy. In 16 patients, rather than a herniated disc they had a lumbar epidural varix, while an arterio-venous fistula was found in the remaining five cases. In all cases, the vascular disorder was resected and its subjacent disc was left intact. One patient had a postoperative blood transfusion. While the radiculopathy dysfunction improved in all patients, four patients reported lasting lumbar pain following surgery. The postoperative imaging confirmed the resolution of the vascular anomaly and an intact disc. The mean length of the follow-up period was 47 months. Either epidural varix or arterio-venous fistula in the lumbar area may mimic a herniated disc on imaging studies. With the usual technique they can be operated safely. Resection of the anomaly can be sufficient for alleviating radiculopathy symptoms.

Spinal dural and epidural fistulas: role of cone beam CT in diagnosis and treatment

Understanding normal spinal arterial and venous anatomy, and spinal vascular disease, is impossible without flow-based methods. Development of practical spinal angiography led to site-specific categorization of spinal vascular conditions, defined by the 'seat of disease' in relation to the cord and its covers. This enabled identification of targets for highly successful surgical and endovascular treatments, and guided interpretation of later cross-sectional imaging.Spinal dural and epidural arteriovenous fistulas represent the most common types of spinal shunts. Although etiology is debated, anatomy provides excellent pathophysiologic correlation. A spectrum of fistulas, from foramen magnum to the sacrum, is now well-characterized.Most recently, use of cone beam CT angiography has yielded new insights into normal and pathologic anatomy, including venous outflow. It provides unrivaled visualization of the fistula and its relationship with spinal cord vessels, and is the first practical method to study normal and pathologic spinal veins in vivo-with multiple implications for both safety and efficacy of treatments. We advocate consistent use of cone beam CT imaging in modern spinal fistula evaluation.The role of open surgery is likely to remain undiminished, with increasing availability and use of hybrid operating rooms for practical intraoperative angiography enhancing safety and efficacy of complex surgery.

Spinal Dorsal Intradural Arteriovenous Fistulas: Natural History, Imaging, and Management

In this review, we describe the pathophysiology, diagnosis, and treatment of spinal dorsal intradural arteriovenous fistulas (DI-AVFs), focusing on novel research areas. DI-AVFs compose the most common subgroup of spinal arteriovenous lesions and most commonly involve the thoracic spine, followed by lumbar and sacral segments. The pathogenesis underlying DI-AVFs is an area of emerging understanding, thought to be attributable to venous congestion and hypertension that precipitate ascending myelopathy. Patients with DI-AVFs typically present with motor, sensory, or urinary dysfunction, although a wide swath of other less common symptoms has been reported. DI-AVFs can be subdivided by spinal region, which in turn is associated with 4 distinct clinical phenotypes: craniocervical junction (CCJ), subaxial cervical, thoracic, and lumbosacral. Patients with CCJ and lumbosacral DI-AVFs have particularly interesting presentations and treatment considerations. High-value diagnostic findings on MRI include flow voids, missing-piece sign, and T2-weighted intramedullary hyperintensity. However, digital subtraction angiography is the gold standard for diagnosis and localization of DI-AVFs and for definitive treatment planning. Surgical disconnection of DI-AVFs is almost universally curative and frontline treatment, especially for CCJ and lumbosacral DI-AVFs. Endovascular techniques evolve in promising ways, such as improved visualization, distal access, and liquid embolic techniques. The pathophysiology of DI-AVFs is better understood using newly identified radiologic diagnostic markers. Despite new techniques and devices introduced in the endovascular field, surgery remains the gold-standard treatment for DI-AVFs.

Surgical evolution in spinal dural arteriovenous fistula treatment-a 7 years monocentric experience

Accounting for 70% of all spinal vascular malformations, spinal dural arteriovenous fistulas (SDAVF) are the most common type of malformation. Interruption of the fistulous arterialized vein point is the goal of surgical treatment. The aim of the study was to compare open surgery (laminectomy) versus minimal invasive surgery (MIS) in SDAVF treatment. Between March 2013 and March 2020, we retrospectively collected 21 consecutive adult patients with SDAVF. Since March 2017, MIS has been routinely used for surgical treatment. Pre- and post-operative clinical evaluations used Aminoff-Logue score (ALS). Complication rate was noted. Post-operative occlusion of the malformation was confirmed by digital subtraction angiography (DSA) in all patients. MIS was compared to open surgery in terms of efficacy and complications with statistical evaluation. Standard laminectomy was performed in 12 patients and MIS technique in 9 patients. No difference was noted on pre-operative parameters. ALS and MRI signs of myelopathy were improved in all cases except for 1 patient in each group. All SDAVFs were excluded based on post-operative DSA. Significant differences were noted between the 2 groups in terms of perioperative blood loss (p<0.001), post-operative pain visual analog scale values (p<0.001), and first time out of bed (p<0.001). Wrong level surgery occurred in one patient in each group; patients were re-operated using the same technique. No infection or cerebrospinal fluid (CSF) leak was noted. In our experience, MIS is a safe alternative to open laminectomy for SDAVF treatment. MIS contributes to patient comfort and minimizes blood loss without increasing complication rate.

Surgical and Endovascular Treatments for Asymptomatic Arteriovenous Fistulas at the Craniocervical Junction: A Multicenter Study

OBJECTIVE

Asymptomatic craniocervical junction arteriovenous fistulas (CCJ AVFs) are rare and, thus, a consensus has not yet been reached regarding the indication of surgical interventions. This retrospective multicenter cohort study investigated the risks associated with surgery for asymptomatic CCJ AVFs and discussed the indication of surgical interventions.

METHODS

Using data from 111 consecutive patients with CCJ AVFs registered with the Neurospinal Society of Japan between 2009 and 2019, we analyzed the treatment, complications, and outcomes of 18 patients with asymptomatic CCJ AVF.

RESULTS

The median age of the patient cohort was 68 years (37-80 years), and there were 11 males and 7 females. Diagnoses were 14 patients with dural AVF, one perimedullary AVF, one radicular AVF, one epidural AVF, and one bilateral dural and epidural AVF. Initial treatment included direct surgery in 12 patients, endovascular treatment in four, and conservative treatment in two. Among 16 patients, three complications (18.7%) occurred: spinal cord infarction associated with the surgical procedure, cerebral infarction associated with intraoperative angiography, and mortal medullary hemorrhage after endovascular treatment followed by open surgery. Complete occlusion was achieved in all 12 patients in the direct surgery group and in one out of four in the endovascular treatment group.

CONCLUSIONS

Given the risk of serious complications associated with asymptomatic CCJ AVF and the fact that no case of asymptomatic CCJ AVF became symptomatic in this study, prophylactic surgery for asymptomatic CCJ AVF should be carefully considered.

Spinal Dural Arteriovenous Fistulas: A Retrospective Analysis of Prognostic Factors and Long-Term Clinical Outcomes in the Light of the Recent Diagnostic and Technical Refinements

Spinal dural arteriovenous fistulas (dAVFs) are abnormal connections between the meningeal branches of segmental arteries and a radiculomedullary veins that result in a progressive myelopathy thanks to perimedullary coronal venous plexus congestion. Usually, dAVFs show nonspecific symptoms, thus leading to late clinical suspicion and a difficult MRI diagnosis.Several authors have tried to identify prognostic factors before treatment, but published studies results are often inconsistent and sometimes contradictory.In this study, we reviewed our recent experience of 30 dAVF patients where we collected all demographic, clinical and angioarchitectural features as well as radiological and treatment-related characteristics. The thoracic spine was the most common location, constituting 53.3% of cases, followed by the lumbar roots, comprising 30%. About 83% of patients showed motor deficits, urinary disturbances were present in 70%, and bowel symptoms in 50%.We treated 86.7% of patients with microsurgery and 13.3% with endovascular occlusion with a mean interval between clinical onset and intervention of 10.8 ± 14.2 months.A significant clinical improvement was observed at follow-up in 80% of patients, with a significant reduction in mean G-score, U-score and F-score at a mean follow-up of 105.89 ± 191.9 months.However, none among the principal demographic, clinical and radiological characteristics showed significant prognostic value to the clinical improvement observed at follow-up.

Acute neurological deterioration after surgical interruption of spinal dural arteriovenous fistulas: clinical characteristics, possible predictors, and treatment. Patient series

BACKGROUND

Acute neurological deterioration develops paradoxically in some patients after obliteration of a spinal dural arteriovenous fistula (SDAVF), with thrombosis of the spinal cord veins as its primary cause. The authors aimed to clarify the clinical and radiological characteristics of acute deterioration to identify high-risk patients. They also discussed the optimal treatment for this complication.

OBSERVATIONS

Ten patients with SDAVF presenting with congestive myelopathy who received microsurgical interruption were retrospectively reviewed. Severe myelopathy developed in three patients on postoperative days 1 to 3. Anticoagulation therapy was effective; however, discontinuing anticoagulants under residual spinal cord congestion caused redeterioration. These patients were characterized by significantly extended transit time on angiography and significant prolongation of spinal cord congestion. Acute deterioration exhibited a strong correlation with transit time (coefficient, 0.825; p = 0.006) and a strong correlation with spinal cord edema before surgery (coefficient, 0.656; p = 0.040).

LESSONS

Acute deterioration after SDAVF treatment is likely to develop in patients with severe venous outflow impairment. Its pathology is prolonged spinal cord congestion caused by postoperative venous thrombosis and preexistent severe venous outflow impairment. Anticoagulation treatment should be continued for patients with acute deterioration until the resolution of spinal cord congestion is confirmed with magnetic resonance imaging.

Vascular Myelopathies

PURPOSE OF REVIEW

Neurologists should be able to identify clinical and neuroimaging features that distinguish vascular disorders from other causes of myelopathy.

RECENT FINDINGS

Although certain clinical features suggest a vascular etiology in acute and chronic myelopathy settings, accurate MRI interpretation within the clinical context is key. Recent studies have shown vascular myelopathies are frequently misdiagnosed as transverse myelitis, and recognition of this diagnostic pitfall is important. Many different vascular mechanisms can cause myelopathy; this article provides a comprehensive review that simplifies disease categories into arterial ischemia, venous congestion/ischemia, hematomyelia, and extraparenchymal hemorrhage.

SUMMARY

It is important to recognize and manage vascular disorders of the spinal cord as significant causes of acute, subacute, and progressive myelopathy.

Arteriovenous Fistula at the Craniocervical Junction Found After Cervical Laminoplasty for Ossification of the Posterior Longitudinal Ligament

Ossification of the posterior longitudinal ligament (OPLL) is common in East Asia. Arteriovenous fistula at the craniocervical junction (CCJ-AVF), in contrast, is rare. As OPLL occurs most often in the cervical region, these 2 conditions can coexist in the cervical spinal canal of a single patient. We report a case of CCJ-AVF found after cervical laminoplasty (CLP) for OPLL. A 68-year-old man experienced progressive myelopathy due to cervical OPLL. Magnetic resonance imaging (MRI) revealed a high-intensity area inside the spinal cord. CLP was performed and his symptoms immediately improved. Three months after CLP, however, myelopathy recurred. MRI revealed an exacerbated and enlarged high-intensity area inside the cord from the medulla oblongata to the C4/5 level with a flow void around the cord. Left vertebral artery angiography revealed CCJ-AVF with ascending and descending draining veins. Direct surgery was performed to interrupt shunt flow into the draining veins. The patient’s symptoms improved to a limited degree. In this case, increased pressure inside the spinal canal due to OPLL might have decreased the shunt flow of the CCJ-AVF. Thus, the venous congestion induced by CCJ-AVF might have been exacerbated after the pressure was removed by CLP. Magnetic resonance angiography screening could help detect concurrent CCJ-AVF and OPLL.

Asymptomatic spinal dural arteriovenous fistula: case series and systematic review

OBJECTIVE

Spinal dural arteriovenous fistulas (SDAVFs) commonly present with symptoms of myelopathy due to venous congestion in the spinal cord; asymptomatic SDAVFs are rarely encountered. To elucidate the clinical characteristics of asymptomatic SDAVFs, the authors present 5 new cases of asymptomatic SDAVF and report the results of their systematical review of the associated literature.

METHODS

Five databases were systematically searched for all relevant English-language articles on SDAVFs published from 1990 to 2018. The clinical features and imaging findings of asymptomatic SDAVFs were collected and compared with those of symptomatic SDAVFs.

RESULTS

Twenty cases, including the 5 cases from the authors' experience, were found. Asymptomatic SDAVFs were more prevalent in the cervical region (35.0%); cervical lesions account for only 2% of all symptomatic SDAVFs. The affected perimedullary veins tended to drain more cranially (50.0%) than caudally (10.0%). Four cases of asymptomatic SDAVF became symptomatic, 1 case spontaneously disappeared, and the remaining 15 cases were unchanged or surgically treated.

CONCLUSIONS

The higher prevalence of asymptomatic SDAVFs in the cervical spine might be a distinct feature of asymptomatic SDAVFs. Given that venous congestion is the pathophysiology of a symptomatic SDAVF, abundant collateral venous pathways and unique flow dynamics of the CSF in the cervical spine might prevent asymptomatic cervical SDAVFs from becoming symptomatic. In cases in which venous congestion is avoidable, not all asymptomatic SDAVFs will become symptomatic.

Dural Arteriovenous Fistulas at the Craniocervical Junction: A Series Case Report

BACKGROUND

Craniocervical junction dural arteriovenous fistulas (CJDAVFs) are rare vascular malformations with unclear clinical characteristics. This study investigated the clinical characteristics and outcomes of patients with CJDAVFs.

METHODS

Thirty-eight patients with CJDAVFs who had undergone either conservative or surgical treatment were retrospectively analyzed.

RESULTS

Eleven (28.9%) patients were women and 27 (71.1%) were men (median age, 52.5 years). Two (5.3%) had myelopathy, and 36 (94.7%) had subarachnoid hemorrhage (SAH). Three patients had SAH recurrence before treatment. Five patients (13.9%) with SAH initially had negative results on angiography, which may have been due to a low-flow fistula without varicose veins (P = 0.034) and acute hydrocephalus (P = 0.084). Coincidental vascular lesions were noted in 5 patients (13.2%). Caudal drainage was mainly found in patients with myelopathy, whereas superolateral drainage was frequently observed in patients with SAH (P = 0.021). Thirty-six (94.7%) patients underwent microsurgery; of these, 33 (91.7%) had favorable outcomes and 3 (8.3%) had unfavorable outcomes. The main neurosurgical complications included acute hydrocephalus in 4 (10.5%) and new-onset mild persistent myelopathy in 6 (15.7%). According to the univariate analysis, the presence of myelopathy predicted poor outcomes, whereas SAH predicted favorable outcomes (P = 0.004). However, the multivariate analysis did not show statistical significance.

CONCLUSIONS

SAH is a common presenting sign of CJDAVF that may be overlooked on initial cerebral angiography, especially in patients with acute hydrocephalus and a low-flow fistula without varicose veins. Microsurgery involving disconnecting the draining vein is effective and beneficial. Further studies should be performed to investigate predictive factors influencing the prognosis.

Spinal Dural Arteriovenous Fistula Assumed to be Symptomatic after Placement of Lumbar Cerebrospinal Fluid Drain

A 69-year-old man presented with severe headache. Cranial computed tomography revealed diffuse subarachnoid hemorrhage. An anterior communicating artery aneurysm was identified and successfully obliterated by open microsurgery on the same day. Following placement of a continuous lumbar cerebrospinal fluid drain on hospitalization day 7, the patient developed a severe paraplegia and sensory loss below T6. Cerebral magnetic resonance imaging did not identify a responsible lesion. Spinal magnetic resonance imaging, however, showed extensive intramedullary hyperintensity on T2-weighted sequences. Spinal angiography identified a dural arteriovenous fistula fed by the segmental artery branching with the 12th intercostal artery. It was successfully embolized and the patient's sensorimotor disturbances remarkably improved. A spinal dural arteriovenous fistula may better be considered as one of the underlying etiologies when patients exhibit new neurological deficits after placement of a continuous lumbar cerebrospinal fluid drain.

Clinical outcomes and prognostic factors in patients with spinal dural arteriovenous fistulas : a prospective cohort study in two Chinese centres

BACKGROUND

The short-term outcomes and prognostic factors of patients with spinal dural arteriovenous fistulas (SDAVFs) have not been defined in large cohorts.

OBJECTIVE

To define the short-term clinical outcomes and prognostic factors in patients with SDAVFs.

METHODS

A prospective cohort of 112 patients with SDAVFs were included consecutively in this study. The patients were serially evaluated with the modified Aminoff and Logue's Scale (mALS) one day before surgery and at 3 months, 6 months and 12 months after treatment. Univariate and multivariate analyses were performed to identify demographic, clinical and procedural factors related to favourable outcome.

RESULTS

A total of 94 patients (mean age 53.5 years, 78 were men) met the criteria and are included in the final analyses. Duration of symptom ranged from 0.5 to 66 months (average time period of 12.7 months). The location of SDAVFs was as follows: 31.6% above T7 level, 48.4% between T7 and T12 level (including T7 and T12) and 20.0% below T12 level. A total of 81 patients (86.2%) underwent neurosurgical treatment, 10 patients (10.6%) underwent endovascular treatment, and 3 patients (3.2%) underwent neurosurgical treatment after unsuccessful embolisation. A total of 78 patients demonstrated an improvement in mALS score of one point or greater at 12 months. Preoperative mALS score was associated with clinical improvement after adjusting for age, gender, duration of symptoms, location of fistula and treatment modality using unconditional logistic regression analysis (p<0.05).

CONCLUSION

Approximately four fifths of the patients experienced clinical improvement at 12 months and preoperative mALS was the strongest predictor of clinical improvement in the cohort.

Microsurgical treatment and outcomes of spinal arteriovenous lesions: Learned from consecutive series of 105 lesions

Spinal arteriovenous lesions (SAVLs), arteriovenous fistulas (AVFs) and arteriovenous malformations (AVMs), are rare and can devastatingly impair spinal cord function. This study aimed to evaluate clinical outcomes after microsurgical treatment with the aid of intraoperative indocyanine green video-angiography (ICG-VA) in a large series of patients with SAVLs. We retrospectively reviewed the cases of 95 consecutive patients with 105 SAVLs (77 spinal AVFs, 28 spinal AVMs) who had been treated surgically during 2010-2016 in two hospitals by the same experienced surgeon. All patients had undergone magnetic resonance imaging and digital subtraction angiography preoperatively and were assessed using the modified Aminoff and Logue Scale (mALS). All lesions were resected or occluded using ICG-VA. No ICG-VA-related complications occurred. Compared with AVF, patients with AVM tended to be younger (p<0.001) and were at higher risk of an associated aneurysm (p=0.021), hemorrhage (p<0.001), pain (p<0.001) and abrupt onset (p<0.001). SAVLs were most common in the lower thoracic region (45.71%), and their most common clinical presentation was paresthesia (89.52%). At a mean follow-up of 33.3months, mALS indicated significant improvement in patients with spinal AVFs (p<0.001) and AVMs (p=0.002) compared with their status preoperatively. An improved, stable clinical status was noted at the last follow-up in 93.51% of those with AVFs and 89.28% of those with AVMs. Thus, microsurgical treatment of SAVLs produced a lasting positive clinical outcome in a large cohort of consecutive patients. ICG-VA proved to be an efficient intraoperative tool during resection of these lesions, especially in patients with an AVF.

Cord Topographical Anatomy and its Role in Evaluating Intramedullary Lesions

Intramedullary spinal lesions present a wide differential diagnosis including infectious, inflammatory, traumatic, ischemic, benign, or malignant neoplastic etiologies. Using knowledge of anatomy and physiology within the spinal cord, many similar appearing entities can be parsed into a prioritized differential. The purpose of this article is to review anatomy and pathophysiology of the spinal cord, with subsequent discussion of how this knowledge can be used to differentiate several similar appearing intramedullary pathologic processes. Discussion includes the pathophysiology, imaging findings, and clinical pearls of several intramural lesions including infarct, demyelinating lesions, traumatic injury, neoplasm, vascular malformation, and metabolic processes such as subacute combined degeneration.

Arterial Hypertension Is Associated with Symptomatic Spinal Dural Arteriovenous Fistulas

OBJECTIVE

To determine possible systemic factors that may induce or be associated with the pathogenesis and pathologic course of spinal dural arteriovenous fistulas (SDAVFs), the most common type of arteriovenous disorder of the spinal cord and its meninges.

METHODS

We assessed the role of possible systemic (vascular) risk factors (arterial hypertension, diabetes mellitus, fat metabolism disorders, and nicotine dependence) by comparing the prevalence of these risk factors in an SDAVF cohort of 59 patients with the prevalence in the general population.

RESULTS

Age-corrected prevalence of arterial hypertension in the SDAVF cohort was significantly higher than in the general population (P < 0.001). Prevalence of diabetes mellitus (P = 0.150.), nicotine dependence (P = 0.561), adiposity (P = 0.217), and fat metabolism disorders (P = 0.125) did not differ from prevalence of comparable cohorts in the general population.

CONCLUSIONS

Our results and data from the literature suggest that arterial hypertension may play an important role in the development of SDAVF-related symptoms or the development of SDAVFs in the presence of other predisposing factors.

Spinal arteriovenous fistulas in adults: Management of a series of patients treated at a neurology department

OBJECTIVE

Spinal arteriovenous fístulas (SAVF), a rare type of vascular malformation, account for 3% of all spinal cord lesions. Without early treatment, the associated morbidity is high; furthermore, SAVF pose a major diagnostic challenge. Our purpose was to evaluate the clinical characteristics of SAVF and review their progress after treatment to determine whether it may be too late for treatment in some cases.

METHODS

We present a retrospective series of 10 patients diagnosed with SAVF and treated at a tertiary hospital during a 3-year period.

RESULTS

In our sample, SAVF were found to be significantly more frequent in men (80%). Mean age in our sample was 65.4 years. The most common initial symptom was intermittent claudication/paraparesis (70%). In most patients, symptoms appeared slowly and progressively. At the time of diagnosis, the most common symptoms were motor, sensory, and sphincter disorders. Mean time from symptom onset to diagnosis was 24.3 months. Initial diagnosis was erroneous in 60% of the patients. Spinal MRI was diagnostic in 90% of these cases and arteriography in 100%. The most common location of the fistula was the lower thoracic region and the most frequent type was dural (7 cases). All patients were treated with embolisation, surgery, or both and 70% improved after fistula closure regardless of progression time.

CONCLUSIONS

Diagnosis of SAVF is difficult and often delayed, which leads to poorer patient prognosis. We should have a high level of suspicion for SAVF in patients with intermittent claudication or paraparesis exacerbated by exercise. Early treatment should be started in these patients. Treatment should always aim to improve quality of life or stabilise symptoms, regardless of progression time.

Spinal Dural Arteriovenous Fistula: Imaging Features and Its Mimics

Spinal dural arteriovenous fistula (SDAVF) is the most common spinal vascular malformation, however it is still rare and underdiagnosed. Magnetic resonance imaging findings such as spinal cord edema and dilated and tortuous perimedullary veins play a pivotal role in the confirmation of the diagnosis. However, spinal angiography remains the gold standard in the diagnosis of SDAVF. Classic angiographic findings of SDAVF are early filling of radicular veins, delayed venous return, and an extensive network of dilated perimedullary venous plexus. A series of angiograms of SDAVF at different locations along the spinal column, and mimics of serpentine perimedullary venous plexus on MR images, are demonstrated. Thorough knowledge of SDAVF aids correct diagnosis and prevents irreversible complications.

Intramedullary hemorrhage from a thoracolumbar dural arteriovenous fistula

BACKGROUND CONTEXT

Spinal dural arteriovenous fistulas (AVFs) are acquired lesions presenting typically with neurologic deficits secondary to chronic congestive myelopathy. The low-flow and low-volume nature of these lesions makes hemorrhage very unlikely, and intramedullary hemorrhage caused by thoracolumbar dural AVFs is exceedingly rare.

PURPOSE

The purpose of this study was to report a case of intramedullary hemorrhage caused by a thoracolumbar dural AVF.

STUDY DESIGN/SETTING

The study design included a case report and review of literature.

METHODS

A case of intramedullary hemorrhage from a thoracolumbar dural AVF was reported, and the literature regarding hemorrhagic presentations of dural AVF was reviewed.

RESULTS

A 66-year-old woman presented with a sudden onset of abdominal pain, paraplegia, sensory loss below the costal margins, and urinary retention. Magnetic resonance imaging scan showed intramedullary hemorrhage with abnormal flow voids raising suspicion of an intramedullary AV malformation. However, subsequent selective spinal angiography demonstrated a spinal dural AVF fed by the T7 intercostal artery and a varix within the draining vein. Complete obliteration of the dural AVF and the varix was achieved via embolization. As far as we are aware, there are only two other similar cases in the literature. Literature review revealed that presentation of thoracolumbar dural AVFs with hemorrhage is frequently associated with accelerated venous flow and the presence of a venous varix.

CONCLUSIONS

Although very unusual, a spinal dural AVF may present with intramedullary hemorrhage, and hemorrhage in such conditions may be associated with an accelerated venous flow and the presence of a venous varix.

Surgical treatment of spinal extradural arteriovenous fistula with parenchymal drainage: report on 5 cases

BACKGROUND AND IMPORTANCE

Spinal extradural arteriovenous fistula (SEDAVF) with parenchymal drainage (type A) is a rare clinical entity that causes venous congestive myelopathy. Treatment includes endovascular and open microsurgical interventions. We reviewed the clinical records of patients treated for a type A SEDAVF to evaluate the feasibility of our treatment strategy.

CLINICAL PRESENTATION

Between 2004 and 2010, 5 patients with a type A SEDAVF were treated at our institutes (4 men and 1 woman; mean age, 60 years). We performed endovascular transvenous embolization (TVE) when lesions were accessible transvenously; otherwise, microsurgical perimedullary drainer occlusion was performed. Follow-up ranged from 23 to 94 months (mean, 45.8 months). One patient was treated with TVE, and the remaining 4 were treated with microsurgical drainer occlusion. After a simple intradural drainer occlusion, an epidural venous lake was completely thrombosed in 2 patients. In 1 patient, postoperative angiography revealed that a part of the epidural component had persisted; however, the patient has been asymptomatic. In the remaining case with multiple intradural draining veins, sole drainer occlusion was not sufficient. A second surgery was required to meticulously coagulate the venous lake. As a consequence, parenchymal drainers disappeared. Overall, all patients stabilized or improved neurologically and experienced no recurrence.

CONCLUSION

To treat a type A SEDAVF, either TVE or microsurgical intradural drainer occlusion can be used for satisfactory long-term results with minimal surgical risks. For a case with multiple intradural draining veins, detachment of the venous lake should be considered.

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.

MRI and MRA of spinal cord arteriovenous shunts

The purpose of this review is to describe the diagnostic criteria for spinal cord arteriovenous shunts (SCAVSs) when using magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA), and to discuss the extent to which the different MRI and MRA sequences and technical parameters provide the information that is required to diagnose these lesions properly. SCAVSs are divided into four groups according to location (paraspinal, epidural, dural, or intradural) and type (fistula or nidus); each type of lesion is described. SCAVSs are responsible for neurological symptoms due to spinal cord or nerve root involvement. MRI is usually the first examination performed when a spinal cord lesion is suspected. Recognition of the image characteristics of vascular lesions is mandatory if useful sequences are to be performed-especially MRA sequences. Because the treatment of SCAVSs relies mainly on endovascular therapies, MRI and MRA help with the planning of the angiographic procedure. We explain the choice of MRA sequences and parameters, the advantages and pitfalls to be aware of in order to obtain the best visualization, and the analysis of each lesion.