Spinal Angiography Research Articles

Experience of 14 cases using hemi-semilaminectomy microsurgery treating by spinal dural arteriovenous fistula

Objective: To explore the efficacy and feasibility of the hemi-semilaminectomy microsurgical operation treatment of spinal dural arteriovenous fistula (SDAVF). Methods: The clinical data of 32 patients with SDAVF were analyzed retrospectively. Before operation all patients were diagnosed by spinal MRI and spinal angiography, 14 patients were treated by hemi-semilaminectomy approach and other 18 patients were by traditional laminectomy approach. All the data were analyzed by T test and P<0.05 was considered to have significant difference. Results: The nidus of SDAVF located on thoracic segments in 18 cases, lumbar segments in 12 cases, and cervical segment in 2 cases, which was fed by single artery. The hemi-semilaminectomy microsurgical operation showed shorter operation time, less bleeding, less hospitalization time and cost. All the patients followed-up for 6 months-2 years. Symptoms of all the patients were improved compared with those before surgery. Conclusions: On the premise of spinal angiography accurately positioning the location of fistula, the hemi-semi-laminectomy approach microsurgery clipping operation is safe and feasible, and the operation has fewer traumas, also helps to maintain the stability of spine.

Dilated Vein of the Filum Terminale on MRI: A Marker for Deep Lumbar and Sacral Dural and Epidural Arteriovenous Fistulas

Conventional MR imaging can provide important clues regarding the location of a spinal vascular malformation. We hypothesized that a dilated vein of the filum terminale, identified as a curvilinear flow void on T2WI, could be an imaging marker for a lower lumbar (L3-L5) or sacral fistula. We retrospectively identified all spinal dural and spinal epidural arteriovenous fistulas from 2 large tertiary referral centers from 2005 to 2018. All patients had a lumbar spinal MR imaging and a conventional spinal angiography. Images were reviewed by 2 neuroradiologists who categorized the level of the arterial feeder to the fistula and the presence or absence of a dilated vein of the filum terminale on T2WI and T1 postcontrast images. We calculated the sensitivity, specificity, positive predictive value, and negative predictive value of the presence of a dilated filum terminale vein for a deep lumbar or sacral fistula. One hundred sixty-two patients were included. An enlarged filum terminale vein was identified in 39 patients. Sensitivity, specificity, positive predictive value, and negative predictive value of the presence of a dilated filum terminale vein for a deep lumbar or sacral fistula were 86%, 98.3%, 94.9%, and 95.1%, respectively. The presence of a dilated vein of the filum terminale can accurately localize a spinal dural arteriovenous fistula/spinal epidural arteriovenous fistula to the lower lumbar or sacral spine in patients being evaluated for such lesions. This finding can be used to facilitate both noninvasive and conventional spinal angiography.

SPINAL DURAL ARTERIOVENOUS FISTULA: CLINICAL CASE AND LITERATURE REVIEW

Spinal dural arteriovenous fistula (SDAVF) is a rare disease, however, with nonspecific initial symptoms, like back pain, parestesias, gait imbalance, weakness and numbness in extremities. Para- or tetraparesis, disturbance of deep sensation and pelvic organs functions may develop during the course of disease. There isn’t any specific laboratory tests. So, the diagnostics of dural fistulas is complex. The main screening method is magnetic resonance tomography (MRI), which may suspect or reveal dural fistula. Spinal angiography is a «golden standard» in diagnostics. Options of treatment include microsurgical separation or endovascular embolisation of fistula. The article presents a clinical case of SDAVF in thoracic region of spine. Related to complains, neurological exam and MRI data, the vascular mass was suspected and spinal angiography was per-formed to confirm the presence of SDAVF. After surgical treatment the patient was observed to rehabilitation course, which had improved his status. In sum, appropriate diagnostics, surgical intervention and rehabilitation are the main factors related to successful treatment of patients with SDAVF.

Surgical Treatment of Vascular Intramedullary Spinal Cord Lesions.

BackgroundVascular lesions represent a rare subset of intramedullary spinal cord pathology and consist of cavernous malformations (CM), hemangioblastomas, and arteriovenous malformations (AVM). These lesions are each unique and the literature pertaining to their surgical management is largely limited to retrospective case series and case reports.ObjectivesTo evaluate the surgical management of each of these lesions with special attention to postoperative functional status.MethodsA single-institution case series of intramedullary vascular lesions treated with surgery was retrospectively evaluated. The primary variables of interest included preoperative and postoperative McCormick grades. Other variables of interest included frequency and indication for conventional spinal angiography, rates of preoperative embolization, postprocedural complications, operative time, intraoperative blood loss, and length of hospital stay.ResultsThirty-six patients were identified over the 17-year study period, including 20 with hemangioblastomas, 13 with CMs, and three with AVMs. The median preoperative McCormick grades were 2, 2, and 3 for hemangioblastomas, CMs, and AVMs, respectively. The median postoperative McCormick grades were 2, 2, and 2 for hemangioblastomas, CMs, and AVMs, respectively at the most recent follow-up. Preoperative angiography was performed in all AVM cases and 29% of hemangioblastomas. Preoperative embolization was performed in 40% of hemangioblastoma cases undergoing preoperative angiography. Operative times were similar between the three lesion groups. In three cases of hemangioblastoma resection and one case of CM resection, McCormick grade improved by one point following surgery. At a mean follow-up of 30.9 months for hemangioblastomas, 7.95 months for CMs, and 24 months for AVMs, all patients were at least at their discharge baseline, with no new neurologic complaints.ConclusionIntramedullary vascular lesions are rare and represent a complex surgical patient population. Surgical resection with or without preoperative angiography and embolization appears to be safe and to halt neurologic decline.

Ruptured Spinal Arteriovenous Malformation: A Rare Cause of Paraplegia in Pregnancy

Background Ruptured spinal arteriovenous malformation (AVM) is a rare cause of paraplegia in pregnancy, with only a few case reports describing complications from spinal AVMs during pregnancy in the literature. Case A 32-year-old woman presented at 37 weeks gestation with back pain and rapidly progressive lower limb neurological symptoms. MRI showed a previously undiagnosed spinal AVM at T8. A healthy girl was delivered by caesarean under general anaesthesia to facilitate further investigation. After spinal angiography, it was concluded the most likely aetiology was acute rupture of an intra- and perimedullary AVM with associated haemorrhage at T8 secondary to venous compression from the enlarged uterus at L5 causing high pressure within the AVM and subsequent rupture. The neurosurgical and interventional radiology teams felt the lesion was not amenable to surgical or endovascular intervention. The patient remained paraplegic with no sign of neurological recovery six months after delivery. Conclusion While new onset paraplegia during pregnancy secondary to ruptured spinal AVM is very rare, it is important to discuss these cases to inform future practice. In contrast to previous case reports, our patient did not spontaneously recover after delivery and was not amenable to surgical or endovascular treatment.

Spinal dural arteriovenous fistula: delay to radiological diagnosis and sources of radiological error

To highlight the magnetic resonance imaging (MRI) signs associated with spinal dural arteriovenous fistula (SDAVF) through categorisation of sources of radiological error and investigation of the delay to radiological diagnosis. This was a retrospective, observational study of cases referred to a neuroscience centre over 11 years. All patients who underwent spinal digital subtraction angiography (DSA) with a subsequent diagnosis of SDAVF were identified. Prior imaging was reviewed and compared with the formal reports issued. Thirty-seven patients with SDAVF were initially imaged in seven institutions. Radiological abnormalities including intradural vessels (37/37, 100%), cord T2 signal change (34/37, 91.9%), and cord expansion (26/37, 70.2%) were present on prior MRI. These signs were not recognised in 22/37 (59.5%), 7/34 (20.5%), and 15/26 (57.7%) of cases, respectively. Increased T2 signal in the cord was the most commonly identified sign (27/34; 79.4%), but prompted either no diagnosis (7/34; 20.5%) or differential diagnoses including ischaemic, inflammatory, or neoplastic aetiologies or a syrinx in 11/34 (32.4%). An appropriate diagnosis was made on initial MRI in 15 patients (40.5%). The time from initial imaging to diagnosis was significantly delayed for those patients who did not have an arteriovenous vascular aetiology included in the initial differential diagnosis (281 (423.3) days versus 22 (15.7) days, p=0.03). SDAVF have imaging features that are frequently missed or misinterpreted. This results in a significant delay to definitive diagnosis and therefore treatment.

Application of Gemstone Spectrum Imaging for anterior spinal artery in patients with cervical spinal injury

To discuss the value of Gemstone Spectrum Imaging (GSI) CT anterior spinal artery angiography in the patients with cervical spinal cord injury, and to evaluate the correlation between the change of the blood flow of the anterior spinal artery and the postoperative recovery of nerve function. From January 2014 to June 2016, thirty patients who underwent cervical open door laminoplasty for spinal cord injury were retrospective analyzed and included 21 males and 9 females with an average age of (46.4±9.7) years old ranging from 33 to 59 years. Within 2 weeks after injury, open door laminoplasty was performed through cervical posterior approach. Among them, there were 8 cases of 3 segments of open door decompression, 18 cases of 4 segments, 4 cases of 5 segments. GSI CT were performed at 3 days before operation and 5 days after operation. The anterior spinal artery was reconstructed and evaluated the improvement of blood flow after operation. The cervical JOA score was calculated at 1 day before operation, 5 days after operation and 1, 6 and 12 months after operation, and the JOA score improvement rate of the corresponding follow-up points was calculated. All patients were followed up for 12 to 30 months with an average of (17.4±7.6) months. The iodine content ratio (ASA/VA) of the anterior spinal artery before and after operation was 0.75±0.20 and 0.89±0.02 respectively, the postoperative improvement was significantly higher than that before operation(P<0.01). The average ASA/VA improvement rate was(21.05±12.45)% after operation. There was a positive linear correlation between the improvement of blood flow and the improvement of JOA score at 1, 6 and 12 months after operation. GSI CT anterior spinal artery angiography is safe and feasible, the imaging is satisfactory, it can quantitatively evaluated the blood flow of the anterior spinal artery. There was a positive linear correlation between the improvement of blood flow in anterior spinal artery and the recovery of neurological function. Early postoperative improvement of blood flow in the anterior spinal artery can be used as a reference index for predicting the recovery of neurological function in patients.

Primary intramedullary spinal cord tumour in pregnancy: a case report.

Primary spinal cord tumours can lead to severe neurological complications and even death. Pregnant women often complain of discomfort of the lower limbs, which is usually caused by sciatica. Here we present the case of a pregnant woman, who was initially considered to have sciatica, but was finally diagnosed with a primary intramedullary spinal cord tumour. A 28-year-old pregnant woman presented to our hospital with inexplicable numbness in her lower limbs. She was initially considered to have sciatica, but acute deterioration of neurological symptoms and plain magnetic resonance imaging (MRI) findings suggested malignancy. The patient was finally diagnosed with a primary intramedullary spinal cord tumour at the C3-Th5 region. An emergency caesarean section was performed, after which the spinal cord lesion was evaluated using contrast-enhanced MRI, positron emission tomography with 2-deoxy-2-[fluorine-18] fluoro-d-glucose integrated with computed tomography, and spinal angiography, and further treatment was initiated. However, while the patient's spinal cord tumour surgery was performed in early postpartum, her paraplegia and bladder and rectal disturbances remained unchanged even 1 year after surgery. Because of the low incidence of spinal cord tumours during pregnancy, no definite reports have been published on the treatment of pregnant patients with spinal cord tumours. Although safe imaging tests during pregnancy are limited, intervention in such patients should be performed as early as possible to avoid irreversible neurological deterioration.

Acute progressive paraplegia in heroin-associated myelopathy

As the opioid epidemic continues, understanding manifestations of abuse, including heroin-associated myelopathy remains essential. Here we describe a young man with a past medical history significant for polysubstance abuse who developed acute-onset, rapidly progressive myelopathy after resumption of intravenous heroin use. He had significant spinal cord involvement with findings suggestive of heroin-associated myelopathy. The salient features of this case include diffusion imaging of the spine and spinal angiography supporting a possible vasculopathy as the pathophysiologic mechanism underlying heroin-associated myelopathy. Additionally, CSF studies showed the transition from a neutrophilic pleocytosis to a lymphocytic pleocytosis suggesting an inflammatory component.

Angiography Before Posterior Mediastinal Tumor Resection: Selection Criteria and Patient Outcomes

Resection of posterior mediastinal tumors may be complicated by bleeding or neurologic injury. Preoperative spinal angiography of mediastinal tumors has been underreported or not commonly practiced. This study evaluated the selection criteria and outcomes of patients with posterior mediastinal tumors who underwent preoperative angiography and embolization. This was a single-institution retrospective study of patients with posterior mediastinal tumors from 2002 to 2016. Multilevel spinal angiography was performed, with or without selective arterial embolization of vascular supply, in patients selected by thoracic or neurologic surgeons. Ten of 87 patients (11%) with posterior mediastinal tumors underwent preoperative angiography. A mean of 11 arteries (range, 2 to 25) were studied. Embolization in 7 of 10 patients successfully occluded 1 to 3 arteries. There was no significant difference in age, sex, body mass index, American Society of Anesthesiologists Physical Status Classification, operative time, operative blood loss, complications, or death between patients with or without angiography. Patients who underwent angiography had larger tumors (1,490 vs 97 cm3, p < 0.0001), involvement of the neuroforamen (44% vs 10%, p < 0.05), and a longer hospital stay (9 vs 4.5 days, p < 0.05). Angiography was complicated in 1 patient by vocal cord ulceration after intubation of a tumor-compressed trachea. Shared blood supply between the tumor and the spinal cord precluded embolization and tumor resection in 1 patient. Use of angiography increased over time. Selective preoperative angiography for evaluation of posterior mediastinal tumors identifies arterial variations, threatened spinal arteries, and targets for embolization. The specific role of angiography and embolization requires further investigation to standardize indications and protocols for the number of arteries examined.

Endovascular surgery of spinal dural arteriovenous fistulas

To evaluate the efficacy of endovascular treatment of SDAVFs, depending on the pathophysiological mechanisms of impact on the spinal cord. For the last 5 years (2013-2017), 302 patients with SDAVFs were diagnosed and treated at the Neurosurgical Institute. The endovascular technique was used in 295 patients with this pathology. Males accounted for 82%; females accounted for 18%; the mean age was 51 years. Magnetic resonance imaging (MRI) was used to assess the degree of spinal cord involvement. All SDAVF patients underwent total selective spinal angiography in order to study angioarchitectonics and to choose an endovascular treatment option. Endovascular embolization of fistulas was performed in 295 out of 302 patients; direct surgery was used in the remaining cases. Endovascular treatment provided total SDAVF occlusion in 78% of cases and partial SDAVF occlusion in 22% of cases. Long-term outcomes were followed-up in all patients in a period of 6 to 12 months. In 90% of cases, improvement or stabilization of neurological symptoms was observed. In 60% of cases, there was a marked improvement in the neurological status in the form of rapid (within a few days) recovery of lost motor functions. The remaining patients had stabilization of clinical symptoms.

Clinical and Radiologic Characteristics of Deep Lumbosacral Dural Arteriovenous Fistulas.

Spinal dural arteriovenous fistulas located in the deep lumbosacral region are rare and the most difficult to diagnose among spinal dural arteriovenous fistulas located elsewhere in the spinal dura. Specific clinical and radiologic features of these fistulas are still inadequately reported and are the subject of this study. We retrospectively evaluated all data of patients with spinal dural arteriovenous fistulas treated and/or diagnosed in our institution between 1990 and 2017. Twenty patients with deep lumbosacral spinal dural arteriovenous fistulas were included in this study. The most common neurologic findings at the time of admission were paraparesis (85%), sphincter dysfunction (70%), and sensory disturbances (20%). Medullary T2 hyperintensity and contrast enhancement were present in most cases. The filum vein and/or lumbar veins were dilated in 19/20 (95%) patients. Time-resolved contrast-enhanced dynamic MRA indicated a spinal dural arteriovenous fistula at or below the L5 vertebral level in 7/8 (88%) patients who received time-resolved contrast-enhanced dynamic MRA before DSA. A bilateral arterial supply of the fistula was detected via DSA in 5 (25%) patients. Clinical symptoms caused by deep lumbosacral spinal dural arteriovenous fistulas are comparable with those of spinal dural arteriovenous fistulas at other locations. Medullary congestion in association with an enlargement of the filum vein or other lumbar radicular veins is a characteristic finding in these patients. Spinal time-resolved contrast-enhanced dynamic MRA facilitates the detection of the drainage vein and helps to localize deep lumbosacral-located fistulas with a high sensitivity before DSA. Definite detection of these fistulas remains challenging and requires sufficient visualization of the fistula-supplying arteries and draining veins by conventional spinal angiography.

MS 11.03 Surgical Approaches in Superior Sulcus Tumor

Complete en bloc resection is the corner stone of the treatment of solid tumors. Those located in the superior sulcus (SS) or thoracic inlet are known to have bad reputation because their resection represents a real technical challenge. The complexity of such surgery is due to the congestion of a very tight space (SS) by major neurovascular structures as well as to the proximity of the esophagus, the trachea and the spine. The preoperative work-up, in order to assess the involvement of such structures by SS tumors, may include, further to the routine bronchoscopy and cervico thoracic CT scan, an MRI to rule out spinal extension, venous angiography, subclavian arteriography or esophagoscopy. Many surgical approaches to remove SS tumors and many anatomical classifications have been reported during the last 6 decades. The goal of the surgical approach is to allow a wide and safe exposure of the SS, complete en-bloc resection of the tumor and all the involved structures and a potential arterial or spinal resection and reconstruction. The main goal of an anatomical classification is to facilitate the choice of the most appropriate surgical approach according to the extension of the tumor. After an anatomical description of the SS, we will review all the surgical approaches described in the literature to remove benign or malignant tumors developed in the SS. The emergence of new surgical techniques during the last 2 decades, such video-assisted and robotics surgeries had modify the surgical approaches in thoracic surgery. We will describe all the surgical approaches currently available to resect SS tumors with their advantages and their limits. Based on our experience we will describe a simplified anatomical classification of SS tumors. After identification of all contra-indications to SS tumor resection, we will describe the surgical approaches we use currently allowing when needed arterial and spinal resections and reconstructions.

Fístulas arteriovenosas durales medulares: las malformaciones vasculares más frecuentes de la médula espinal

Spinal dural arteriovenous fistulas are produced by direct communication between the arterial and venous systems of the spinal cord, causing hypertension in the latter with spinal cord dysfunction. It is a rare pathology with unknown etiology and non-specific clinical symptoms that usually results in a delayed diagnosis. Often radiologists are the first to guide the disease towards an adequate diagnosis. Characteristic findings can be seen through MR or MR angiography, and may even locate the fistula in a high percentage of cases, although the pathology must be confirmed by spinal angiography. There are two treatment modalities: endovascular and surgical therapy. Endovascular treatment has improved in recent years with the advantages of a less invasive approach and is therefore usually chosen as primary therapy. In this article we review the main clinical manifestations, imaging findings and treatment of this pathology.

Diagnosis of spinal dural arteriovenous fistula using 3D T2-weighted imaging.

To evaluate spinal MRIs without and with 3D T2W imaging among patients without and with spinal dural arteriovenous fistula (SDAVF) confirmed by spinal digital subtraction angiography (DSA). A retrospective case-control study was performed among patients without and with SDAVF who had both spinal MRIs and gold standard spinal DSA. Two neuroradiologists independently reviewed spinal MRIs that were performed with either sagittal T2W turbo spin echo (2D group) or sagittal 3D T2W sampling perfection with application-optimized contrasts using different flip-angle evolutions (SPACE) (3D group) and documented the presence or absence of SDAVF. Using spinal DSA diagnosis as a gold standard, the sensitivity, specificity, and interobserver agreement for the 2D-group and 3D-group MRI diagnosis were calculated. The 2D group consisted of 21 patients and the 3D group consisted of 16 patients. For both radiologists, the 2D group demonstrated a sensitivity of 100% and specificity of 100%. Interobserver agreement in the 2D group was perfect (k=1.0). For both radiologists, the 3D group demonstrated sensitivity of 100.0% and specificity of 92.3%. Interobserver agreement in the 3D group was perfect (k=1.0). While flow voids were considered more conspicuous, spinal cord signal abnormality was considered less conspicuous with 3D T2W SPACE compared with conventional 2D STIR sequence. 3D T2W SPACE should be used in conjunction with 2D T2W sequences to more accurately detect abnormal cord signal and determine when perimedullary flow voids are pathologically abnormal for the radiologic diagnosis of SDAVF.

Comprehensive Evaluation of Diagnostic and Treatment Strategies for Idiopathic Spinal Subarachnoid Hemorrhage

Idiopathic spinal subarachnoid hemorrhage (IS-SAH), defined as spinal SAH without apparent cause, is extremely rare. The objective of the present study was to establish a consensus on the diagnosis and management of IS-SAH. We enrolled 5 consecutive cases of IS-SAH at our institution, and we enrolled 19 previously published cases as a literature review. The patient presentations, diagnostic test findings, treatment strategies, and outcomes were retrospectively assessed. Possible causes of spinal SAH were basically excluded by multimodalities, including brain and spinal digital subtraction angiographies. IS-SAH usually developed in middle-aged people around 55 years old and typically presented with acute migrating back pain. Lumbar puncture and spinal magnetic resonance imaging demonstrated xanthochromia or an abnormal intensity area around the spine in all study patients who underwent these diagnostic tests. All of the patients from our institution were discharged with 1 patient (20%) complaining of neurologic dysfunction at discharge, and 1 patient (5.3%) in the published cases died during hospitalization and 5 (26.3%) complained of neurologic dysfunction at discharge. In addition, the surgical findings in 1 case from our institution suggested that one of the mechanisms of IS-SAH is a bleeding from a microvessel around the spine, and we newly propose spinal drainage as one of the treatment options in patients with IS-SAH based on our experience. We summarized our experience of 5 cases of IS-SAH with a literature review. We demonstrated that spinal drainage could be one of the treatment options in patients with IS-SAH.

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

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

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

Spinal dural arteriovenous fistulae (sdAVF) are rare lesions. Patients typically present with slowly progressive myelopathy that is often mistaken for degenerative cervical or lumbar stenosis. On spinal magnetic resonance imaging (MRI), multisegmental T2 hyperintensities along with associated flow voids are pathognomonic of sdAVF. However, diagnosis can be difficult. Definitive diagnosis and localization is achieved with complete spinal angiography. Treatment options include open surgical ligation, endovascular embolization or multimodality treatment. The purpose of this study is to present a series of cases to aid in the assessment, diagnosis and treatment of this unusual pathology. We present 10 cases of sdAVF treated at our center over an 8-year period. Seventy percent of patients were male. The mean age of presentation was 62.6 years. The most common lesion was a dorsal dural AVF with single feeder. All patients underwent open surgical ligation, six having preoperative coil embolization of the radicular artery to allow for intraoperative localization of the fistula. Eight patients showed improvement following treatment as graded by the Nurick system. Two patients failed to improve. None of the patients worsened. One patient had a radiation burn from the spinal angiogram requiring secondary closure and one patient had a pseudomeningocele at the site of surgery that resolved. The successful treatment of sdAVF requires a detailed understanding of clinical presentation and imaging findings to allow for precise treatment. Owing to the rarity of the condition, clinicians must continue to share their experiences to advance our knowledge.

Clinical pitfall: false-positive aquaporin-4 IgG leading to misdiagnosis of neuromyelitis optica spectrum disorder in patient with spinal arteriovenous fistula.

We report the cases of a 68-year-old male with a filum terminale arteriovenous fistula (AVF) who was initially misdiagnosed with neuromyelitis optica spectrum disorder (NMOSD) based on imaging findings and false-positive aquaporin-4 IgG (AQP4-IgG). A 68-year-old male presented with slowly progressive weakness and numbness in his bilateral lower extremities. He was initially diagnosed with NMOSD and treated with immunosuppressive therapy based on findings of extensive spinal cord edema on magnetic resonance imaging (MRI) and initial negative spinal angiography as well as positive AQP4-IgG. Despite immunosuppressive treatment, his symptoms progressed slowly. He repeated MRI that showed persistent abnormal signal within the spinal cord. Second spinal angiography revealed filum terminale dural arteriovenous fistula (AVF). Finally, he underwent surgical disconnection of the fistula. Repeated AQP-IgG was reported negative. Although NMOSD and spinal AVFs can share imaging findings on spinal cord MRI, typical clinical features of each disorder are distinct. Identification of AQP4-IgG is the hallmark to confirm a clinical diagnosis of NMOSD; however, different assays can vary in sensitivity and specificity. Although it is rare, false positives can occur especially at low titers. A misdiagnosis of NMOSD and delayed diagnosis of spinal AVF had significant clinical implications because the treatment of spinal AVF is surgical disconnection or endovascular embolization, whereas the treatment for NMOSD includes long-term immunosuppressive therapy. Clinicians should be aware of the potential technical issues in detecting AQP4-IgG especially in the context of patients with atypical presentations for NMOSD.

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

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