Spinal dural arteriovenous fistulas: clinical features in 80 patients

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.

Delayed Diagnosis of Spinal Dural Arteriovenous Fistula: A Case Report and Scoping Review

Spinal dural arteriovenous fistula (SDAVF) is among the most common arterial shunt diseases typically found in middle aged or older men. Herein, we aimed to clarify the reasons for misdiagnoses and delayed diagnoses of SDAVF, determine how these affect prognoses, and establish how they can be prevented. We conducted a PubMed/MEDLINE literature search using "spinal dural arteriovenous fistula", "delayed diagnosis", "late diagnosis", and "misdiagnosis" terms. We identified 18 articles, including 965 SDAVF cases. Patients were predominantly males (71.8-100.0%) (mean age: 53.5-71.0 years). Misdiagnoses rates varied (17.5-100.0%) and encompassed many conditions. The mean time between early manifestations and confirmed diagnosis was approximately 10-15 months and from the first radiologic image revealing dural arteriovenous fistula (DAVF) features to diagnosis was 9.2-20.7 months. Posttreatment outcomes showed a significant improvement in motor functions, gait, and micturition, particularly in patients exhibiting preoperative symptoms over a short period. SDAVF is frequently misdiagnosed or subject to delayed diagnosis, causing poor clinical outcomes. SDAVF symptoms including progressive lower-limb weakness, paresthesia, and vesicorectal dysfunction are indications for spinal magnetic resonance imaging with subsequent spinal angiography, wherein DAVF is evidenced by extensive T2 hyperintensity and flow-void abnormalities. We reported a representative case with delayed diagnosis.

Spinal dural arteriovenous fistula: a comprehensive review of the history, classification systems, management, and prognosis

Spinal dural arteriovenous fistulas account for the majority of spinal vascular malformations. They are typically located in the thoracolumbar region and are diagnosed in the middle-aged and elderly populations. Although spinal dural arteriovenous fistulas have been postulated to be acquired, their exact development remains uncertain. Typically, the arteriovenous shunt is situated close to the spinal nerve root, inside the dura mater, where the blood from the radiculomeningeal artery and radicular vein intermix. Throughout history, there have been multiple classification systems of spinal arteriovenous shunts since 1967. Those were mainly based on the evolution of diagnostic studies as well as the treatment of these lesions. Such classification systems have undergone significant changes over the years. Unlike intracranial dural arteriovenous fistula, spinal dural arteriovenous fistula is progressive in nature. The neurological manifestations, due to venous congestion, tend to be insidious as well as non-specific. These include sensory deficits, such as paresthesia, bilateral and/or unilateral radicular pain affecting the lower limbs, and gait disturbances. Spinal dural arteriovenous fistulas can be suspected on magnetic resonance imaging/magnetic resonance angiography and confirmed by digital subtraction angiography (DSA). The management includes surgery, endovascular therapy, and in selected cases, radiotherapy. The treatment goal of spinal dural arteriovenous fistula is to halt the progression of the disease. The prognosis depends on both the duration of symptoms as well as the clinical condition prior to therapy. The present article comprehensively reviews the pathophysiology, changes in classification systems, natural history, clinical manifestations, radiological features, management, and prognosis.

Progressive conus medullaris lesions are suggestive of intravascular large B-cell lymphoma

BACKGROUND AND PURPOSE

Spinal cord lesions are observed in 40% of all central nervous system lesions in intravascular large B-cell lymphoma (IVLBCL). However, because IVLBCL is a very rare disease, its clinical features are not well defined, which may delay appropriate diagnosis and treatment, whilst the acute to subacute course of brain lesions in patients with IVLBCL is well established. Therefore, this study aimed to clarify the clinical features of spinal cord lesions in patients with IVLBCL.

METHODS

The medical records of patients with IVLBCL admitted to our hospital between 2010 and 2020 were searched. The inclusion criteria were preceding neurological symptoms without non-neurological symptoms and pathologically confirmed IVLBCL in various organs. Clinical features of spinal cord involvement in patients with IVLBCL were assessed and distinguished from those of brain involvement.

RESULTS

Sixteen consecutive patients with IVLBCL were divided into two groups: six patients with spinal involvement (spinal cord type) and 10 patients with brain involvement (brain type). In the spinal cord type, four patients had chronic progression and two had subacute progression. Acute progression (0% vs. 80.0%) and sudden onset (0% vs. 50.0%) occurred significantly less frequently in the spinal cord than in the brain. All spinal cord lesions involved the conus medullaris.

CONCLUSIONS

Spinal cord involvement in IVLBCL has a predominantly chronic progressive course that is exclusive to brain involvement. Conus medullaris lesions are suggestive of IVLBCL and are useful for early and accurate diagnosis and treatment.

Vascular Myelopathies

There are many vascular disorders that can affect the spinal cord, and their prevalence and etiology are highly influenced by age, sex, and risk factors. This article reviews the embryology and anatomy of the spinal cord, as well as several vascular conditions, describing their clinical and imaging presentation, emphasizing the different imaging modalities' contributions to increasing specificity and better defining the most appropriate therapy strategy for improving the patient's prognosis.

Bilateral mirror image lumbar spinal dural arterial venous fistula: a rare case and systematic review of the literature

BACKGROUND

Spinal dural arteriovenous fistulas (SDAVF) are rare with an incidence of 5-10/million annually. They can be difficult to diagnose causing a delay in treatment with significant morbidity. We describe the first case in the literature of a symptomatic mirror lumbar SDAVF which may go unnoticed due to its unique vascular anatomy.

CASE DESCRIPTION

A 78-year-old gentleman presented with a progressive deterioration in his walking distance and urinary retention. An initial MRI scan of the whole spine did not show features suggestive of an underlying vascular malformation. During further investigations of neurological causes, the patient continued to have progressive symptoms over a 10-month period resulting in a repeat MRI scan. This showed a new finding of cord oedema without abnormal flow voids. He went on to have vascular imaging which demonstrated a mirror L3 SDAVF and underwent subsequent surgical management. At follow up there was a significant improvement in symptoms.

CONCLUSIONS

Completing a systematic review of the literature we find that the mirror lumbar SDAVF in our patient presented in a more aggressive manner with symptoms progressing faster than in single or multi-level SDAVF. Our case demonstrates how this unique vascular anatomy may result in a diagnostic challenge, behaving in an occult way where typical findings are not seen on initial MRI scanning. We provide an argument for early vascular imaging which can result in the treatment of these lesions in a timely manner.

Cost-Effectiveness of Forgoing Postoperative Catheter Angiography After Microsurgical Occlusion of Spinal Dorsal Intradural Arteriovenous Fistulas

OBJECTIVE

Spinal dorsal intradural arteriovenous fistulas (DI-AVFs) represent 70% of all spinal vascular lesions. Diagnostic tools include pre- and postoperative digital subtraction angiography (DSA) and intraoperative indocyanine green videoangiography (ICG-VA). ICG-VA has a high predictive value in DI-AVF occlusion, but postoperative DSA remains a core component of postoperative protocols. The aim of this study was to evaluate the potential cost reduction of forgoing postoperative DSA after microsurgical occlusion of DI-AVFs.

METHODS

Cohort-based cost effectiveness study of all DI-AVFs within a prospective, single-center cerebrovascular registry from January 1, 2017, to December 31, 2021.

RESULTS

Complete data including intraoperative ICG-VA and costs were available for 11 patients. Mean (SD) age was 61.5 (14.8) years. All DI-AVFs were treated with microsurgical clip ligation of the draining vein. ICG-VA showed complete obliteration in all patients. Postoperative DSA was performed for 6 patients and confirmed complete obliteration. Mean (SD) cost contributions for DSA and ICG-VA were $11,418 ($4,861) and $12 ($2), respectively. Mean (SD) total costs were $63,543 ($15,742) and $53,369 ($27,609) for patients who did and did not undergo postoperative DSA, respectively. Comorbidity status was identified as the main driver of total cost (P = 0.01 after adjusting for postoperative DSA status).

CONCLUSIONS

ICG-VA is a powerful diagnostic tool in demonstrating microsurgical cure of DI-AVFs, with a negative predictive value of 100%. Eliminating postoperative DSA in patients with confirmed DI-AVF obliteration on ICG-VA may yield substantial cost savings, in addition to sparing patients the risk and inconvenience of a potentially unnecessary invasive procedure.

Angioarchitectural features of arteriovenous fistulas at craniocervical junction predicting clinical presentation and unfavorable neurological function: insight from a multicenter cohort and pooled analysis

Arteriovenous fistulas (AVFs) at the craniocervical junction (CCJ) are uncommon conditions with complex angioarchitecture. The objective of this study was to identify the angioarchitectural features of CCJ-AVF that were predictive of clinical presentation and neurological function. The study encompassed a total of 68 consecutive patients with CCJ-AVF at two neurosurgical centers between 2014 and 2022. Additionally, a systematic review was conducted, including 68 cases with detailed clinical data obtained via PubMed database spanning 1990 to 2022. Clinical and imaging data were collected and pooled together to analyze factors associated with subarachnoid hemorrhage (SAH), myelopathy, and modified Rankin scale (mRS) at presentation. The mean age of the patients was 54.5 ± 13.1 years, with 76.5% of them being male. The most common feeding arteries were V3-medial branches (33.1%), and drainage was frequently through the anterior or posterior spinal vein/perimedullary vein (72.8%). SAH was the most common presentation (49.3%), and an associated aneurysm was identified as a risk factor for SAH (adjusted OR, 7.44; 95%CI, 2.89-19.15). Anterior or posterior spinal vein/perimedullary vein (adjusted OR, 2.78; 95%CI, 1.00-7.72) and male gender (adjusted OR, 3.76; 95%CI, 1.23-11.53) were associated with higher risk for myelopathy. Myelopathy at presentation was an independent risk factor for unfavorable neurological status (adjusted OR per score, 4.73; 95%CI, 1.31-17.12) in untreated CCJ-AVF. The present study identifies risk factors associated with SAH, myelopathy, and unfavorable neurological status at presentation in patients with CCJ-AVF. These findings may help treatment decisions for these complex vascular malformations.

Review of spinal dural arteriovenous fistulas: Challenges, diagnostics, management, and pathophysiology

Spinal dural arteriovenous fistulae are rare, spinal vascular malformations that commonly present with progressive myelopathy in a specific demographic and are treatable with surgery (preferred) and/or endovascular embolization. PubMed and Google Scholar were searched with terms including but not limited to "spinal dural arteriovenous fistula", "imaging", "management" "surgery vs embolization", "outcomes", "pathogenesis" to find relevant studies, including emerging research. The purpose of this literature review is to highlight presentation, imaging characteristics, management strategies, pathophysiology, and future directions for these rare but distinct entities.

Spinal dural arteriovenous fistula: A rare but treatable disease that should not be missed by orthopedic surgeons

Objective

Spinal dural arteriovenous fistula (SDAVF) is a rare disease that is often misdiagnosed by orthopedic surgeons. We analyzed the reasons for the misdiagnosis and proposed countermeasures.

Methods

Twenty-two SDAVF patients who were initially treated in orthopedics were included. The patients were divided into a correct diagnosis group (A) and a misdiagnosis group (B). The clinical data and prognosis were evaluated.

Results

There were 10 patients in group A and 12 patients in group B. The clinical manifestations included limb numbness, weakness, and bladder and bowel dysfunction. Among these patients without spinal degenerative diseases which had typical magnetic resonance imaging (MRI) features in Group A were more than Group B (P < 0.05). More patients had spinal degenerative diseases in group B. In group A, seven patients were primarily diagnosed with a SDAVF after multidisciplinary teamwork (MDT). In group B, five patients were misdiagnosed with lumbar spinal stenosis, four with lumbar disc herniation, two with thoracic spinal stenosis, and one with cervical spinal stenosis and lumbar spinal stenosis and underwent cervical spinal canal and lumbar spinal canal decompression. The length of time for confirming the diagnosis was 7 months longer in group B than in group A. All patients underwent microsurgery treatment. The average follow-up duration was 11 months. The modified Aminoff-Logue Disability Scale scores showed a statistically significant difference in improvement between the two groups (P < 0.05).

Conclusion

when patients with dysuria especially, have intermittent spinal nerve dysfunction, the possibility of SDAVF should be considered. Awareness of the specific clinical and spinal cord edema and flow voids on MRI of a SDAVF needs to be promoted for orthopedic surgeons. Timely MDT is an important measure for reducing misdiagnosis, and steroids or inappropriate surgery should be avoided until a SDAVF is completely excluded.

Progressive Myelopathy With Acute Worsening After Steroids and Lumbar Puncture

We present the case of a 73-year-old woman with a 3-month history of non-traumatic thoracic myelopathy. Initial MRI showed a T6-conus T2 signal hyperintensity. Based on this presentation, and given a personal and family history of autoimmune disease, our patient was first managed as an inflammatory transverse myelitis. Subsequent worsening after lumbar puncture and steroids prompted re-evaluation, ultimately identifying the cause as a thoracic spinal dural AV fistula. Both investigation of possible transverse myelitis with lumbar puncture and empiric treatment with steroids may not only result in diagnostic delays but also precipitate venous infarction and irreversible harm. While the MRI often provides the initial diagnosis, clinical suspicion for this under-diagnosed cause of myelopathy should be raised in older patients with a more progressive thoracic myelopathy with worsening after lumbar puncture and/or steroids. Definitive and time-sensitive treatment by interventional neuroradiology or neurosurgery results in stabilization or improvement of disability in most cases.

Case Report: Differential Diagnosis of Lower Extremity Weakness in a Young Male - Consider Foix Alajouanine Syndrome

Introduction

There is a limited list of emergent spinal cord pathology that must be considered in patients with focal neurological deficits in the emergency department. Identification of these conditions requires a detailed history and neurological exam and may also require advanced testing and imaging.

Case Report

Here we present the case of a patient with a rare arteriovenous malformation of the spinal cord vessels causing congestive myelopathy (Foix-Alajouanine syndrome) that presented as a clinical mimic of spinal cord compression.

Conclusion

Emergency physicians should be aware of Foix-Alajouanine syndrome, as its workup and management differ from more common pathologies that may present similarly.

Intraoperative Spinal Angiography during Microsurgical Occlusion of Spinal Dural Arteriovenous Fistula within the Hybrid Operation Room

BACKGROUND

 Spinal dural arteriovenous fistula (SDAVF) is a rare cause of progressive myelopathy in predominantly middle-aged men. Treatment modalities include surgical obliteration and endovascular embolization. In surgically treated cases, failure of obliteration is reported in up to 5%. The aim of this technical note is to present a safe procedure with complete SDAVF occlusion, verified by intraoperative digital subtraction angiography (DSA).

METHODS

 We describe four patients with progressive leg weakness who underwent surgical obliteration of SDAVF with spinal intraoperative DSA in the prone position after cannulation of the popliteal artery. All surgeries took place in our hybrid operating room (OR) and were accompanied by electrophysiologic monitoring. Surgeries and cannulation of the popliteal artery were performed in the prone position. Ultrasound was used to guide the popliteal artery puncture. A 5-Fr sheath was inserted and the fistula was displayed using a 5-Fr spinal catheter. Spinal intraoperative DSA was performed prior to and after temporary clipping of the fistula point as well after the final SDAVF occlusion.

RESULTS

 The main feeder of the SDAVF fistula in the first patient arose from the right T11 segmental artery, which also supplied the artery of Adamkiewicz. The second patient initially underwent endovascular treatment and deteriorated 5 months later due to recanalization of the SDAVF via a small branch of the T12 segmental artery. The third and fourth cases were primarily scheduled for surgical occlusion. Access through the popliteal artery for spinal intraoperative DSA proved to be beneficial and safe in the hybrid OR setting, allowing the sheath to be left in place during the procedure. During exposure and after temporary and permanent occlusion of the fistulous point, intraoperative indocyanine green (ICG) video angiography was also performed. In one case, the addition of intraoperative DSA showed failure of fistula occlusion, which was not visible with ICG angiography, leading to repositioning of the clip. Complete fistula occlusion was documented in all cases.

CONCLUSION

 Spinal intraoperative DSA in the prone position is a feasible and safe intervention for rapid localization and confirmation of surgical SDAVF occlusion.

Factors Associated with Rapidly Deteriorating Myelopathy in Patients with Spinal Arteriovenous Shunts

Spinal arteriovenous (AV) shunts are rare conditions that sometimes present with myelopathy symptoms. The progression of the symptoms is usually gradual; however, some cases show rapid deterioration. We retrospectively investigated the factors that induced the rapid deterioration of myelopathy symptoms in patients with spinal AV shunts. We treated 33 patients with myelopathy with spinal AV shunts at our institutions, eight of whom experienced rapid deterioration (within 24 hours: 24.2%). Of these, three were related to the body movement or particular postures associated with playing golf, 30 minutes of Japanese straight sitting, and massage care. One patient showed deterioration after embolization for a tracheal aneurysm. The remaining four patients received steroid pulse therapy (high-dose steroid infusion) shortly before the rapid deterioration. These symptoms stopped progressing after cessation of steroid use. While positional or physical factors contributing to myelopathy deterioration might exist, we could not identify specific factors in this study. Nevertheless, rapid deterioration was frequently observed after high-dose steroid use. We must take care not to administer high-dose steroids for myelopathy caused by spinal AV shunt disease.

Rapid Progression to Complete Paraplegia After Electroacupuncture in a Patient With Spinal Dural Arteriovenous Fistula: A Case Report

Spinal dural arteriovenous fistula (SDAVF) usually has an insidious clinical course, but 5–15% of the cases have acute exacerbations. In some cases, there is an abrupt progression to paraplegia following an epidural injection or anesthesia. Electroacupuncture is a form of acupuncture that applies a small electrical current to needles inserted at specific points in the body. It is widely used for its analgesic effect on back pain. In this study, we report a rare case of SDAVF in which the symptoms of a patient worsened rapidly to complete paraplegia within a few hours after applying electroacupuncture to his back. A 49-year-old man had rapid progression to complete paraplegia within a few hours of electroacupuncture on his back. MRI showed SDAVF and worsening of cord signal change. An emergency operation was performed to ligate the SDAVF. The patient was able to walk 1 month post-operatively. Most of the neurological deficits had disappeared by 1 year post-operatively, with normalization of MRI. Our case emphasizes that SDAVF patients should be careful when exposed to any circumstances that might affect the circulation around the dural arteriovenous fistula, such as electroacupuncture. Patients should also be warned in advance about the possibility of rapid exacerbation of neurological symptoms. Regardless of the severity of the neurological symptoms, immediate treatment is essential for recovery and a better outcome.

Sudden-onset paraplegia in a 72-year-old male with a spinal dural arteriovenous fistula: illustrative case

BACKGROUND

Spinal dural arteriovenous fistulas (SDAVFs) are rare vascular malformations of the spine but account for up to 80% of all vascular malformations involving the spine. Few case reports of SDAVFs have been reported in the literature, and even fewer have been described with sudden onset of symptoms.

OBSERVATIONS

The authors described the case of a 72-year-old male with sudden-onset bilateral paraplegia and sensory loss with subsequent inability to bear weight and an initial suspicion of cauda equina syndrome, which was eventually diagnosed as an SDAVF using magnetic resonance imaging. During open surgery, it was difficult to identify the feeder vessels. A postoperative scan showed persistence of the fistula, and the patient had to receive redo ligation with good postoperative status.

LESSONS

Sudden-onset paraplegia is not the typical presentation of SDAVF. All doctors need to be aware of the possibility of an acute presentation with SDAVF, especially with the high likelihood of misdiagnosis and resultant worse outcome due to treatment delays. A high index of suspicion is required to ensure early recognition as well as initiation of treatment.

Spinal dural arteriovenous fistula 8 years after lumbar discectomy surgery: A case report and review of literature

BACKGROUND

Spinal dural arteriovenous fistula (SDAVF) is an extremely rare vascular malformation of the central nervous system that is often confused with degenerative spinal disorders due to similar early symptoms and clinical features. Here, we report a case of SDAVF recurrence 8 years after lumbar spine surgery and summarize relevant literature.

CASE SUMMARY

A 54-year-old male was admitted to our hospital complaining of lower back pain, numbness in both lower extremities and intermittent claudication. Subsequent imaging identified lumbar spinal stenosis. Following surgical treatment, the patient’s symptoms significantly resolved, and he was able to perform daily activities. However, similar symptoms appeared 8 years later, followed by confirmation of SDAVF diagnosis. The patient underwent neurosurgery 7 mo after symptom onset. The follow-up period lasted 14 mo, and the patient remains with marginal neurological symptoms.

CONCLUSION

This case highlights the importance of prompt SDAVF diagnosis. Due to its nonspecific clinical presentation, the clinical experience of the surgeon and definitive imaging examination are indispensable. Additionally, timely neurosurgery is effective and may significantly improve patient outcomes.

Idiopathic acute transverse myelitis in a middle-aged woman with progression to nadir in less than one hour

We report a case of a middle-aged woman, normally fit and well, presenting with acute onset neurological deficit with progression to nadir in <1 hour. Initial MRI spine showed no significant abnormality, although second MRI spine showed abnormal signal in three to four segments with no compressive lesion. CT aortic angiography excluded vascular or ischaemic abnormality. We made a diagnosis of idiopathic acute transverse myelitis (ATM). She was treated with steroids and made significant progress improving from T11 ASIA A paraplegia to T11 ASIA C paraplegia by the time of discharge. Awareness of idiopathic ATM presenting hyperacutely with initial MRI spine being normal is important for prompt diagnosis and management.

Vascular Spinal Cord Disorders

Vascular disorders of the spinal cord are uncommon yet under-recognized causes of myelopathy. Etiologies can be predominantly categorized into clinical and radiographic presentations of arterial ischemia, venous congestion/ischemia, hematomyelia, and extraparenchymal hemorrhage. While vascular myelopathies often produce significant morbidity, recent advances in the understanding and recognition of these disorders should continue to expedite diagnosis and proper management, and ideally improve patient outcomes. This article comprehensively reviews relevant spinal cord vascular anatomy, clinical features, radiographic findings, treatment, and prognosis of vascular disorders of the spinal cord.

A case series of intracranial dural arteriovenous fistulae mimicking cervical myelitis: a diagnosis not to be missed

Objective

To describe the diagnostic features of intracranial dural arteriovenous fistulae (DAVF) presenting with cervical cord or brainstem swelling.

Methods

Retrospective case note and neuroimaging review of patients with angiographically confirmed DAVF diagnosed during January 2015–June 2020 at a tertiary neuroscience centre (Walton Centre NHS Foundation Trust, Liverpool, UK).

Results

Six intracranial DAVF causing cervical cord or brainstem oedema (all males aged 60–69 years) and 27 spinal DAVF (88% thoracolumbar) were detected over a 5.5-year period. Significantly more patients with intracranial DAVF received steroids for presumed inflammatory myelitis than those with spinal DAVF (5/6 vs 1/27, p = 0.0001, Fisher’s exact test). Several factors misled the treating clinicians: atypical rostral location of cord oedema (6/6); acute clinical deterioration (4/6); absence (3/6) or failure to recognise (3/6) subtle dilated perimedullary veins on MRI; intramedullary gadolinium enhancement (2/6); and elevated CSF protein (4/5). Acute deterioration followed steroid treatment in 4/5 patients. The following features may suggest DAVF rather than myelitis: older male patients (6/6), symptomatic progression over 4 or more weeks (6/6) and acellular CSF (5/5).

Conclusion

Intracranial DAVF are uncommon but often misdiagnosed and treated as myelitis, which can cause life-threatening deterioration. Neurologists must recognise suggestive features and consider angiography, especially in older male patients. Dilated perimedullary veins are an important clue to underlying DAVF, but may be invisible or easily missed on routine MRI sequences.

Surgical resection of arteriovenous fistula at the cauda equina

INTRODUCTION

Although spinal arteriovenous fistula (AVF) has been reported widely, AVF at the cauda equina is quite rare. We described a case of AVF at the cauda equina that was fed by the distal radicular artery (DRA).

CASE PRESENTATION

A 50-year-old woman presented with sudden weakness of the lower extremities. Magnetic resonance imaging (MRI) revealed a lesion with a highly intense signal at the conus medullaris, which was surrounded by several low-intensity signals (flow voids). Digital subtraction angiography revealed AVF at the cauda equina and that it was fed by the DRA, which was directly fed by the L3 segmental artery. We performed surgical resection of the AVF while monitoring motor-evoked potentials. The patient's postoperative course was uneventful, and her neurological symptoms gradually resolved. MRI 2 years after surgery showed the disappearance of both intramedullary edema and the flow voids.

DISCUSSION

For the AVF, located at the cauda equina and fed by the DRA in this case, surgical resection or endovascular embolization could have been selected. We performed open surgery to achieve complete obliteration of the AVF, which led to postoperative functional recovery without any adverse events. However, only a limited number of AVFs at the level of the cauda equina have been reported, and treatment standards have not been established. Further studies of AVFs at the cauda equina are necessary to clarify the epidemiological characteristics and clinical outcomes with an appropriate sample size.

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.

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.

Spinal Dural AVFs: Classifications and Advanced Imaging

Spinal dural arteriovenous fistulas (SDAVFs) are the most common vascular shunts of the spine. They occur predominantly in men (more than 80%), commonly involve the thoracolumbar spine, and usually cause progressive myelopathy because of venous congestion of the spinal cord. Recent advanced imaging technology can visualize the detailed angioarchitecture of the spinal cord, and this provides more information of the regional microanatomy related with the shunt disease. We retrospectively analyzed the location of the shunt with adjacent vasculatures and assessed the efficacy and the sensitivity of each imaging modality. Based on these data, a new concept of classification for SDAVFs was reviewed.

Spinal fistulas documented by contrast enhanced computed tomography during myelopathy workup: a lost opportunity

PURPOSE

Low-flow spinal arteriovenous fistulas (SAVFs) with intradural venous drainage typically manifest with a progressive venous hypertensive myelopathy (VHM) in older patients. VHM is difficult to identify. MRI is often nonspecific, and many cases are initially misdiagnosed, most often as transverse myelitis. The workup of myelopathic patients frequently includes thoracic and/or abdominal contrast-enhanced CT (CECT) that are generally not reviewed by neuroradiologists. The purpose of this work was to investigate how often abnormal enhancing intracanalar structures corresponding to the draining veins of a low-flow SAVF were documented by CECT.

MATERIALS AND METHODS

We evaluated 92 consecutive patients with low-flow SAVFs and VHM treated at our institution between 2009 and 2018. The study group included 22 of these patients with at least one thoracoabdominal CECT available for review. The control group consisted of 20 consecutive myelopathy patients with negative angiography and at least one thoracoabdominal CECT. Intracanalar enhancing structures were classified either as (i) conspicuous or (ii) equivocal or absent.

RESULTS

One CECT in the study group was technically inadequate. Conspicuous intracanalar enhancing structures were observed in 20 of the remaining 21 patients with SAVFs (95.2%) and in 2 of 20 control patients (10%). None of the enhancing intracanalar structures was mentioned in official study reports.

CONCLUSIONS

The presence of enhancing vascular structures within the spinal canal on thoracoabdominal CECT obtained during the workup of myelopathies appears to represent a powerful but currently underappreciated tool for the detection of low-flow SAVFs.

Functional Outcome in Patients with Dural Arteriovenous Fistulae after Surgical Treatment

Spinal dural arterio-venous fistulas (SDAVF) are rare vascular pathologies. Degree of symptom improvement after surgery remains unclear. We evaluated surgically treated SDAVF patients for functional outcome and symptom improvement. Retrospective inclusion of consecutive patients treated surgically in our department between 2007–2019. We measured functional outcome using the McCormick Scale and modified Japanese Orthopaedic Association (mJOA) score. We included 27 patients with a median follow-up of 8.8 months (IQR 27.8). Mean age was 61.8 years (SD 8.4), 40.7% were female. Most frequent location was the thoracic spine in 15 (55.6%) followed by lumbar in 8 (29.6%), cervical in 3 (11.1%) and sacral spine in one patient (3.7%). Most common presenting symptom was progressive myelopathy (24/27 patients, 88.9%). In all patients the SDAVF was completely resected; however, four patients (14.8%) required a second surgery. Six patients (22.2%) deteriorated immediately after surgery with five recovering to baseline upon discharge. On discharge, presenting symptoms had improved in 17 patients (63%); 8/25 patients (32%) had a McCormick score of 1. Twenty (74.1%) continued to improve on follow-up. In total 23/27 patients (85.2%) improved. In the univariable analysis mJOA score on admission was associated with mJOA score on follow-up (coefficient 0.6, 95%CI 0.4–0.81, p < 0.001), whereas age was inversely associated (coefficient −0.1, 95%CI −0.19–0.01, p = 0.08). Untreated SDAVF leads to progressive myelopathy which may result in considerable disability. Surgical disconnection and resection provides a safe treatment option with low perioperative morbidity and excellent chances for symptom improvement or progression prevention.

Paralysis After Lumbar Interlaminar Epidural Steroid Injection in the Absence of Hematoma: A Case of Congestive Myelopathy Due to Spinal Dural Arteriovenous Fistula and a Review of the Literature

Paraplegia after interlaminar epidural steroid injection is a rare event and has typically been described after epidural hematoma or direct spinal cord injury. We present a case of an 87-yr-old man who experienced transient lower limb weakness after a lumbar interlaminar epidural steroid injection due to an alternative cause, congestive myelopathy related to an underlying vascular malformation, namely, a spinal dural arteriovenous fistula. This is a poorly recognized and potentially treatable cause of progressive myelopathy. We present this case and review the literature on paraplegia after epidural steroid injection due to spinal dural arteriovenous fistula. Notably, this case of paralysis occurred in association with the lowest volume of epidural injectate reported in the literature to date (4 ml); importantly, this volume is consistent with the current clinical practice guideline standards for the safe performance of interlaminar epidural steroid injections. Physicians should be aware of this potential complication of epidural steroid injection and remain vigilant for the possibility after a procedure, even when performed according to current practice standards.

The Interdisciplinary Management of Foot Drop

BACKGROUND

Foot drop can be caused by a variety of diseases and injuries. Although it is a common condition, its overall incidence has not been reported to date. Foot drop markedly restricts the everyday activities of persons suffering from it. There is, therefore, a need for an optimized strategy for its diagnosis and treatment that would be standardized across the medical specialties encountering patients with this problem.

METHODS

This article consists of a review on the basis of pertinent publications re- trieved by a search in the Pubmed/MEDLINE and Cochrane databases, as well as a description of the authors' proposed strategy for the diagnosis and treatment of foot drop.

RESULTS

Foot drop can be due to a disturbance at any central or peripheral location along the motor neural pathway that terminates in the dorsiflexor muscles of the foot, or at multiple locations in series. Optimal localization of the lesion(s) is a pre- requisite for appropriate treatment and a successful outcome. The most common causes are L5 radiculopathy and peroneal nerve injury. An operation by a neuro- surgeon or spinal surgeon is a reasonable option whenever there is a realistic chance that the nerve will recover. In our opinion, any patient with a subjectively disturbing foot drop and a clinically suspected compressive neuropathy of the peroneal nerve should be informed about the option of surgical decompression of the nerve at the fibular head, which can be performed with little risk. In case of a permanent foot drop, some patients can benefit from muscle-transfer surgery. For spastic foot drop, the option of botulinum toxin injections should be evaluated.

CONCLUSION

The care of patients with foot drop could be optimized by interdisciplin- ary foot-drop clinics involving all of the relevant specialists. The goals of treatment should always be improved mobility in everyday life and the prevention of falls, pain, and abnormal postures.

Steroid-Associated Acute Clinical Worsening and Poor Outcome in Patients With Spinal Dural Arteriovenous Fistulas: A Prospective Cohort Study

STUDY DESIGN

A prospective cohort study.

OBJECTIVE

We conducted a prospective cohort study to identify the association between steroids and clinical worsening and compare outcomes between patients with and without preoperative steroid administration.

SUMMARY OF BACKGROUND DATA

Patients with spinal dural arteriovenous fistulas (SDAVFs) often were misdiagnosed and treated with steroids which led to acute worsening.

METHODS

Patients with angiographically confirmed SDAVFs were recruited consecutively between March 2013 and December 2014 in two referral centers. We reviewed the history of all the patients to identify those patients who were treated with steroids before exclusion of the fistulas. Modified Aminoff & Logue scale (mALS) was used to evaluate the spinal cord function at different time points: before and after steroid administration, before operation, and at 1-year follow-up. Paired t tests were used to assess the mALS of patients with steroid administration at different time points. Unpaired t tests and Pearson chi-square test were used to assess differences between patients with and without steroid administration.

RESULTS

Eighteen patients with (18.2%) and 81 patients without (81.8%) steroid administration were included in this study. At baseline, there were no difference between both patient groups, in regards to age, sex, duration, location of fistula, treatment, and preoperative mALS. Patients without steroid administration, however, had statistically significant better outcome according to their mALS at 1-year follow-up (P < 0.05).

CONCLUSION

Steroid administration can induce acute clinical worsening in patients with SDAVFs that may persist despite successful obliteration of the fistula and should thus be avoided.

LEVEL OF EVIDENCE

3.

Rare Case of Spinal Dural Arteriovenous Fistula with Radiculopathy, without Myelopathy or Spinal Edema on Magnetic Resonance Imaging

BACKGROUND

Spinal dural arteriovenous fistulas (SDAVFs) are the most common type of spinal arteriovenous malformations; they frequently cause progressive myelopathy including gait disturbances and sensory disorders.

CASE DESCRIPTION

We report a rare case of a middle-aged man who experienced right-sided chest pain and Th4 radiculopathy, without any other neurologic presentations. Magnetic resonance imaging showed a flow void sign on the dorsal aspect of the spinal cord; spinal angiography revealed an arteriovenous shunt between a radicular artery and an intradural vein. Suspecting SDAVF as the cause of the chest pain, we performed surgical resection. Intraoperatively, we observed compression of the rootlet by the draining vein. Right chest pain disappeared completely after obliteration of the SDAVF. The present patient had vascular compression of the spinal nerve rootlet without any venous congestion.

CONCLUSIONS

Our experience shows that SDAVF can present not only as a myelopathy but also as a radiculopathy, indicating that radiculopathy may become a main symptom of SDAVF.

Successful embolization of an upper cervical spinal dural fistula despite anterior spinal artery anastomosis

A female in her 40s presented with classic symptoms of subarachnoid hemorrhage and limited mobility of the bilateral upper extremities. Imaging demonstrated a minor amount of subarachnoid blood, and a follow-up computed tomography angiogram revealed a spinal dural arteriovenous fistula (SDAVF) located at C2-3. The C2-3 radicular artery proximal to the fistula feeder anastomosed with the anterior spinal artery, challenging the safety of embolization. However, surgical treatment of the SDAVF would require a suboccipital craniotomy due to its proximity to the foramen magnum, so possible embolization based on lidocaine provocative test results was decided upon. Neurologic examination of the patient following lidocaine provocative testing suggested that embolization could be performed safely. Glue embolization was successfully performed, and the patient awoke without complications. Subsequent imaging revealed no filling of the medullary vein that previously drained the fistula.

Clinical and neuroimaging findings of spinal dural arteriovenous fistulas: How to avoid misdiagnosis of this disease

OBJECTIVE

Spinal dural arteriovenous fistulas (DAVFs) are rare but can cause serious gait and micturition disturbances. Delays in diagnosis and treatment result in poor clinical outcomes; however, the process of misdiagnosis is unknown.

METHODS

Forty consecutive patients were retrospectively analyzed.

RESULTS

Thirty-one patients (78%) were initially misdiagnosed with lumbar spinal stenosis or other diseases, mostly by orthopedic surgeons, even though most patients (85%) had specific symptoms or characteristic neuroimaging findings of spinal DAVFs: they often presented with spastic gait (thoracic myelopathy), progressive ascending numbness that begins in the distal lower extremities (epicous syndrome), and urinary tract symptoms (conus medullaris syndrome); initial lumbar MRI showed T2 signal change in the conus medullaris and vascular flow voids around the cord. The median time from onset to treatment was longer in patients with a misdiagnosis than in those with the correct diagnosis (11 vs 4 months). In all patients, the fistula was completely obliterated by the direct microsurgical procedure; however, patients with a misdiagnosis had developed additional disabilities by the time a correct diagnosis was made (Aminoff-Logue gait grade of 3.6 ± 1.4 vs 2.1 ± 1.5 p = 0.013), and achieved markedly smaller improvements after the treatment (Aminoff-Logue gait grade of 3.0 ± 1.6 vs 1.1 ± 1.5, p = 0.006) than those with the correct diagnosis of spinal DAVFs.

CONCLUSIONS

When common spinal stenosis fail to explain the symptoms such as thoracic myelopathy, epiconus syndrome, and conus medullaris syndrome, the possibility of spinal DAVFs should be considered. If lumbar MRI shows conus medullaris lesions, thoracic MRI should be performed to confirm the diagnosis.

Cauda Equina Occupation Ratio as a New Imaging Parameter for the Evaluation of Spinal Dural Arteriovenous Fistulae

BACKGROUND

Because spinal dural arteriovenous fistulae (SDAVF) are rare and their clinical presentation is nonspecific, they are often overlooked during diagnostic evaluations. Typical magnetic resonance imaging (MRI) findings are intramedullary T2-weighted signal hyperintensity and perimedullary flow voids. There are few reports on the characteristic signs of the cauda equina. We assessed the significance of a new imaging parameter, the cauda equina occupation ratio (CEOR), for the evaluation of SDAVF.

METHODS

We retrospectively analyzed the clinical charts and radiological findings of 20 SDAVF patients treated at our institutions. We evaluated sagittal T2-weighted MRI scans and assessed the CEOR, the occupation ratio of the cauda equina compared to the sagittal diameter of the corresponding lumbar spinal canal. The controls were 21 age- and sex-matched subjects.

RESULTS

Of the 20 SDAVF, 10 were at the thoracic and 10 at the lumbar spine. There was no significant difference between the preoperative CEOR and the spinal level of the fistulae or the neurological signs. On preoperative MRI scans, the mean CEOR was 56.0 ± 7.8; postoperatively, it was 37.1 ± 7.4 (P = 0.000). The preoperative CEOR was significantly larger in SDAVF patients than in the controls (P = 0.000); postoperatively, it was smaller than in the controls (P = 0.14).

CONCLUSIONS

The preoperative CEOR was larger in patients with SDAVF than in the controls. It normalized after successful occlusion of the fistula. Our findings indicate that the CEOR is a useful parameter for the pre- and postoperative evaluation of SDAVF.

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.

Spinal dural arteriovenous fistula presenting as low back pain

Introduction:

Low back pain or numbness of the lower extremities is quite common in the present population. Numerous conditions may cause these symptoms, including spinal vascular anomaly. Identifying and diagnosing the cause of these symptoms are crucial for treatment. Accurate diagnosis based on particular radiological findings in magnetic resonance imaging is crucial for administering adequate therapy to patients, especially in spinal dural arteriovenous fistula.

Case presentation:

We report a case presenting with low back pain and rapid deterioration in paraplegia. Magnetic resonance imaging provided the typical image presentations such as spinal cord edema with tortuous dilated perimedullary venous plexus. The patient was subsequently successfully treated with endovascular embolization.

Discussion:

Spinal dural arteriovenous fistula should be suspected in any patient who presents with myelopathy. Angiography remains the gold standard for confirmation of diagnosis.

Conclusion:

Prompt treatment with endovascular embolization or surgery could improve patients’ outcomes.

Diagnosis and Endovascular Embolization of a Sacral Spinal Arteriovenous Fistula with "Holo-Spinal" Venous Drainage

BACKGROUND

Spinal dural arteriovenous fistulas are the most common spinal vascular pathology, accounting for up to 70% of spinal vascular malformations. They most commonly present with insidious and progressive myelopathy and bowel, bladder, and sexual dysfunction. Although noninvasive imaging (e.g., magnetic resonance imaging, magnetic resonance angiography) may suggest the presence of a spinal arteriovenous fistula (AVF), the diagnosis requires confirmation with spinal angiography.

CASE DESCRIPTION

A 65-year-old woman presented with progressive myelopathy. Traditional spinal angiography of the paired radicular arteries failed to demonstrate any vascular malformation. However, injection of the right internal iliac artery demonstrated an AVF arising from the artery of Desproges-Gotteron with retrograde venous drainage to the upper thoracic region.

CONCLUSIONS

Selective transarterial catheterization and embolization with n-butyl cyanoacrylate resulted in complete occlusion of the AVF. Clinical improvement was also noted on postprocedural day 1. This case highlights the importance of internal iliac injections as a critical component of spinal angiography during an evaluation for vascular malformation.

Use of a New Indocyanine Green Pooling Technique for Improved Visualization of Spinal Dural AV Fistula: A Single-Center Case Series

BACKGROUND

Intraoperative indocyanine green video angiography (ICG-VAG) is a useful tool in cerebral vascular surgery. In spinal procedures such as dural arteriovenous (AV) fistula, use of ICG-VAG is limited due to lower perfusion pressure. Therefore, we developed a new pooling technique with adapted workflow to improve intraoperative visualization.

METHODS

Patients operated on spinal dural AV fistulas using ICG-VAG were prospectively included. A new workflow for ICG-VAG was applied: 1) temporary clip placement at the suspected fistula point, 2) ICG administration during 100% oxygenation, 3) ICG pooling proximal of temporary clip, 4) clip removal/observation of vascular filling. Case records, clinical data, magnetic resonance imaging, digital subtraction angiography (DSA), and clinical outcome were analyzed retrospectively.

RESULTS

A total of 11 patients (median age 68 years, average course of disease 15 months) were included. Optimized, inverted workflow resulted in considerable pooling of ICG in the supplying feeder of the AV fistula in all cases. Complete obliteration was confirmed in 10 of 11 patients by postoperative DSA. However, 1 patient had an additional, preoperative radiologically undetected small feeder that enlarged until postoperative DSA and made successful reoperation necessary. After the median follow-up of 33.2 months, the Aminoff-Logue scale was decreased in all patients, and the McCormick score (modified Rankin score) was improved in 9 (8) patients and remained stable in 2 (3) patients.

CONCLUSIONS

Procedure modification in terms of ICG pooling enabled us to detect more easily the pathologic vascular architecture. ICG-VAG is a useful adjunct in the surgical treatment of spinal dural AV fistula because it is a real-time, noninvasive, and radiation-free technique with adequate image resolution.

Comprehensive review of neuromyelitis optica and clinical characteristics of neuromyelitis optica patients in Puerto Rico

Neuromyelitis optica (NMO) is an immune-mediated inflammatory disorder of the central nervous system. It is characterized by concurrent inflammation and demyelination of the optic nerve (optic neuritis [ON]) and the spinal cord (myelitis). Multiple studies show variations in prevalence, clinical, and demographic features of NMO among different populations. In addition, ethnicity and race are known as important factors on disease phenotype and clinical outcomes. There are little data on information about NMO patients in underserved groups, including Puerto Rico (PR). In this research, we will provide a comprehensive overview of all aspects of NMO, including epidemiology, environmental risk factors, genetic factors, molecular mechanism, symptoms, comorbidities and clinical differentiation, diagnosis, treatment, its management, and prognosis. We will also evaluate the demographic features and clinical phenotype of NMO patients in PR. This will provide a better understanding of NMO and establish a basis of knowledge that can be used to improve care. Furthermore, this type of population-based study can distinguish the clinical features variation among NMO patients and will provide insight into the potential mechanisms that cause these variations.

Comparison of Endovascular Embolization and Surgery in the Treatment of Spinal Intradural Dorsal Arteriovenous Fistulas

BACKGROUND

We compared the outcomes of endovascular embolization and surgery and investigated the factors affecting the clinical outcomes of spinal intradural dorsal arteriovenous fistulas (SIDAVFs).

METHODS

The medical records of 26 patients who had undergone endovascular embolization or surgery for SIDAVFs from 2004 to 2014 were retrospectively reviewed. The recurrence rate and clinical outcomes for each treatment modality were compared. Multivariate analysis was used to identify significant factors influencing the clinical outcomes using the Aminoff and Logue (AL) score.

RESULTS

Of the 26 patients, 14 (56%) had undergone endovascular embolization and 11 (44%) had undergone surgery as the initial treatment. Embolization was applied as the primary treatment for most patients. Surgery was chosen for patients with difficult superselection (n = 5), multiple feeders (n = 2), or easy surgical accessibility (n = 4). Of the 14 patients who had undergone embolization as initial treatment, 5 (36%) had developed a recurrence within an average of 29.6 months (range, 2-87). One patient with recurrent SIDAVF was treated with repeat embolization and four with surgery. None of patients in the surgical group developed recurrence. Embolization as the initial treatment resulted in significantly greater recurrence compared with surgery (odds ratio, 2.222; 95% confidence interval, 1.369-3.608; P = 0.046). Surgery resulted in better clinical outcomes than embolization (P = 0.021). The final AL score was also strongly affected by the preoperative AL score, micturition score, and recurrence (P = 0.000, P = 0.000, and P = 0.011, respectively).

CONCLUSIONS

Our results have shown that surgery results in a low recurrence rate and superior clinical outcomes. A multidisciplinary and ordered decision is crucial for the treatment choice to ensure better outcomes, especially for patients with a definite neurologic deficit at diagnosis.

Electrophysiological Assessment and Classification of Motor Pathway Function in Patients With Spinal Dural Arteriovenous Fistula

PURPOSE

The diagnosis of spinal dural arteriovenous fistula (SDAVF) is difficult and often delayed because clinical features are often nonspecific. We assessed the motor function electrophysiologically in patients with SDAVF.

METHODS

Motor-evoked potentials after transcranial magnetic stimulation and compound muscle action potentials and F-waves after electrical stimulation in the ulnar and tibial nerves were measured from the abductor hallucis (AH) muscles in 14 patients with SDAVF (SDAVF group), 12 patients with compressive thoracic myelopathy (CTM group), and 16 normal subjects (control group). The peripheral conduction time determined from abductor hallucis muscles (PCT-AH) and the central motor conduction time determined from abductor hallucis muscles (CMCT-AH) were calculated. According to the neurological findings, patients in the SDAVF group were classified to upper motor neuron (UMN) sign and lower motor neuron (LMN) sign categories.

RESULTS

CMCT-AH in the SDAVF and CMT groups were significantly longer than those in the control group. PCT-AH in the SDAVF group was significantly longer than that in the control and CMT groups. Twelve patients in the SDAVF group showed abnormal CMCT-AH and/or PCT-AH. Abnormal CMCT-AH and PCT-AH were detected in five cases that exhibited UMN sign and/or LMN sign. Three cases with abnormal CMCT-AH and normal PCT-AH exhibited UMN sign. LMN sign without UMN sign was observed in four cases with abnormal PCT-AH and normal CMCT-AH.

CONCLUSIONS

Our study revealed abnormalities in the corticospinal tract and/or lower motor neurons, and classified the patients with SDAVF into three types: the UMN type, LMN type, and mixed type.