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

Spinal dural arteriovenous fistula: review of clinical presentation, prognosis and imaging findings

Spinal dural arteriovenous fistulas (SDAVF) are rare vascular lesions in the spine. Misdiagnosis is frequent due to non-specific symptoms, which leads to delayed treatment and poorer prognosis. This study reviews the clinical presentation, diagnosis and outcomes of SDAVF cases in Iceland to raise awareness of this rare, but potentially debilitating condition. A retrospective review was conducted of all patients diagnosed with and/or treated for SDAVF at our institution from 2003 to 2024. Medical records were examined for disease duration, severity and prognosis. Imaging was evaluated for features of SDAVF, and outcomes were assessed using the modified Rankin Scale (mRS) and modified Aminoff-Logue Scale (mALS). Seven patients (four males) were identified, with a mean age of 64 and a disease duration of 21 months. Motor, sensory and gait disturbances were present in all patients, as well as bladder dysfunction. Bowel dysfunction (83%) was also common. All patients were wrongfully diagnosed either clinically and/or at imaging, despite showing typical magnetic resonance imaging (MRI) features of SDAVF. All patients underwent successful surgical ligation, with an average of one-point improvement on the mRS and the greatest improvement in gait on the mALS, with an average of one and a half-point improvement. SDAVF should be considered with middle-aged and elderly patients with progressive myelopathy. MRI of at least the thoracic and lumbar spine is essential to include the level of the fistula. Multisegmental T2 hyperintensity and prominent perimedullary flow void should prompt further evaluation with DSA. Post-contrast images and MR angiography may also aid in the diagnosis of SDAVF and guide the DSA.

Implementation of ORBEYE®-Exoscope in the Operative Treatment of Spinal Dural Arteriovenous Fistula

Spinal dural arteriovenous fistulas (sDAVFs) are rather uncommon lesions of the spine. In sDAVFs, which represent the most frequent form of vascular malformations of the spine, operative treatment remains the most common treatment modality. In operative surgery, visualization and pathology detection have a key impact on the results of the neurosurgical treatment of an sDAVF. The exoscope is one of the most recent imaging devices developed alongside the microscope and endoscope. The exoscope is being increasingly applied in neurosurgical procedures as an alternative to operative microscopes due to various advantages, such as its non-space-occupying camera, excellent visualization of the anatomical details and the perfect teaching possibilities it thus provides. In this publication, we present our experience in the treatment of a patient with an sDAVF, where surgery was performed exclusively with an ORBEYE-exoscope for the entire duration of the procedure. This report outlines the workflow and some of the technical pitfalls involved in managing this vascular pathology using the exoscopic technique.

Multiple Synchronous Spinal Dural Arteriovenous Fistulas: A Systematic Literature Review

BACKGROUND AND OBJECTIVES

Spinal dural arteriovenous fistulas (SDAVFs) lead to progressive neurological decline with symptoms such as paraparesis, bowel and bladder dysfunction, and sensory disturbances because of impaired spinal cord venous drainage. This study aimed to systematically review the literature on multiple synchronous SDAVFs and present 2 cases from our institution.

METHODS

A comprehensive search was performed to identify all published cases of multiple synchronous SDAVFs. Overall, 23 patients with multiple synchronous SDAVFs were identified, including 21 from 19 articles and 2 from this study. The clinical presentation, lesion location, radiographic features, surgical treatment, and outcomes were analyzed in each patient.

RESULTS

All patients in this study were male, and the duration from symptom onset to diagnosis in many of these patients was longer than that previously reported. Previous studies suggested that multiple SDAVFs typically occurred within 3 or fewer vertebral levels. However, >50% of the examined patients had remote lesions separated by more than 3 vertebral levels. Patients with remote lesions had a significantly worse outcome (1/7 vs 8/11, 95% CI 0.001-0.998; P = .049).

CONCLUSION

Accurately locating fistulas before spinal angiography is critical for managing multiple remote SDAVFs. Considering the possibility of multiple remote SDAVFs, careful interpretation of imaging findings is essential for an accurate diagnosis and appropriate treatment planning.

An Update on Spinal Dural Arteriovenous Fistulae: Case Series and Systematic Review

Spinal dural arteriovenous fistulae (sDAVFs) are rare entities with delayed diagnosis, potentially dramatic clinical manifestations, and complex management. We aim to present our mini case series and perform an updated systematic review of the usual patient profile, to search for established prognostic factors, to compare the effectiveness and safety of surgical and endovascular intervention, and to discuss trends in therapeutic strategy. We retrospectively collected data from patients treated in our department in the last decade (2014-2024) and we systematically reviewed the literature according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria and searched the PubMed database for relevant articles published in the same period. Epidemiologic data, imaging modalities, prognostic factors, and treatment modalities were assessed. Firstly, we identified four illustrative cases from our institution. In addition, our search yielded 559 studies and our review included 82 original studies. 3130 patients were identified (mean age 61; male-to-female ratio 3:1). Most commonly, the fistula level was in the thoracic spine (65%). Surgery was provided to 1837 patients (1213 as primary treatment) and embolism to 1085 (932 as primary treatment). Initial fistula occlusion rate and recurrence rate were 98.1% and 1.9% for surgery and 71.1% and 9.6% for embolism, respectively. No difference between the two modalities with respect to clinical outcome was observed. SDAVFs remain a challenge for neurosurgeons concerning both diagnosis and management. Surgery remains superior to embolism with respect to success as an initial treatment. Embolism can be offered if certain contraindications do not coexist. All symptomatic patients should be offered treatment, whereas asymptomatic patients could be conservatively managed only if the close patient follow-up can be secured.

A Case Report of Spinal Arteriovenous Fistula: Vague Presentation and Successful Outcome

Spinal arteriovenous fistula (spinal AVF) malformation is one of the rare spinal vascular diseases. Its presentation could be misleading as the patient presents with spinal cord dysfunction, including motor power loss.  Early detection is essential and requires a high suspicion by the providing physician so the patient can be rightfully directed to the proper team with vascular intervention resources. Efficient management leads to promising outcomes with patient recovery. We are presenting a case with progressing motor and sensory neurological deficits that had a vague clinical course. After a prompt diagnosis of spinal AVF, the patient was referred to the neuro-vascular specialist, who performed an embolization of the spinal AVF. The patient had an excellent outcome and was discharged to a rehabilitation facility.

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

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

A Rare Case of Post-Traumatic Cervical Ligamentous Tear Complicated by Vertebral Arteriovenous Fistula (vAVF), with Successful Endovascular Treatment

Post-traumatic vertebral arteriovenous fistula (vAVF) caused by motor vehicle accidents (MVA) is a rare condition in which there is abnormal communication between the vertebral artery and its adjacent veins. In a post-MVA setting, it is commonly associated with vertebral body fracture. In this paper, we report a case of a 19-year-old girl with a complete C2/C3 anterior and posterior ligament tear post MVA without any cervical bony injury. Initial plain computed tomography (CT) cervical scan showed a prevertebral hematoma. A CT angiogram (CTA) raised the suspicion of a pseudo-aneurysm at the right posterior C3 vertebral body. Further imaging with magnetic resonance imaging (MRI) demonstrated traumatic AVF at the C2/C3 level involving the V2/V3 right vertebral artery to the vertebral venous plexus. Digital Subtraction Angiography (DSA) further revealed a transected right vertebral artery at the C2/C3 level with an arteriovenous fistula and an enlarged vertebral venous plexus. The fistulous communication was successfully occluded with coils from a cranial and caudal approach to the transected segment right vertebral artery, with a total of eight coils. Post-MVA vertebral arteriovenous fistula (vAVF) is a rare sequela of vertebral bony injury at the cervical region, and is an even rarer association with an isolated ligamentous injury, whereby endovascular treatment with ipsilateral vertebral artery closure is a feasible treatment of vAVF.

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.

MRI characteristics of lumbosacral dural arteriovenous fistulas

Background and purpose

Spinal dural arteriovenous fistulas located in the lumbosacral region are rare and present with nonspecific clinical signs. The purpose of this study was to find out the specific radiologic features of these fistulas.

Methods

We retrospectively reviewed the clinical and radiological data of 38 patients diagnosed with lumbosacral spinal dural arteriovenous fistulas in our institution from September 2016 to September 2021. All patients underwent time-resolved contrast-enhanced three-dimensional MRA and DSA examinations, and were treated with either endovascular or neurosurgical strategies.

Results

Most of the patients (89.5%) had motor or sensory disorders in both lower limbs as the first symptoms. On MRA, the dilated filum terminale vein or radicular vein was seen in 23/30 (76.7%) patients with lumbar spinal dural arteriovenous fistulas and 8/8 (100%) patients with sacral spinal dural arteriovenous fistulas. T2W intramedullary abnormally high signal intensity areas were found in all lumbosacral spinal dural arteriovenous fistula patients, with involvement of the conus present in 35/38 (92.1%) patients. The "missing piece sign" in the intramedullary enhancement area was seen in 29/38 (76.3%) patients.

Conclusion

Dilatation of the filum terminale vein or radicular vein is powerful evidence for diagnosis of lumbosacral spinal dural arteriovenous fistulas, especially for sacral spinal dural arteriovenous fistulas. T2W intramedullary hyperintensity in the thoracic spinal cord and conus, and the missing-piece sign could be indicative of lumbosacral spinal dural arteriovenous fistula.

Congestive myelopathy due to spinal dural arteriovenous fistula mimicking CNS demyelinating disease

Spinal dural arteriovenous fistula (SDAVF) is known for its ambiguous and various clinical presentations. Among these presentations, congestive myelopathy is one of the most common, yet it is challenging to correctly diagnose SDAVF at initial presentation. Several diseases present as myelopathy, including demyelinating diseases. Herein, we present two cases of congestive myelopathy due to SDAVF presenting to the emergency room (ER) with progressive quadriparesis. Even though the patients had a proper magnetic resonance imaging (MRI) examination from the initial presentation, there was a delay in making a final diagnosis. Both patients' clinical presentation and MRI mimicked central nervous system (CNS) demyelinating disease initially, and a more thorough examination revealed SDAVF. Such a delay in diagnosis can result in more neurological deterioration and may result in more sequelae. Hence, SDAVF should always be considered as a differential diagnosis when examining patients with myelopathy.

Concomitant spinal dural arteriovenous fistula and nodular fasciitis in an adolescent: case report

Background

Spinal dural arteriovenous fistula (SDAVF) usually occurs during the 4^th to 6^th decades of life, and adolescent SDAVF is rarely reported. SDAVF arising around a tumor is also rare, and reported tumors are mostly schwannoma and lipoma.

Case presentation

We reported a 16-year-old male presented with progressive weakness and numbness of lower limbs for 3 months. A SDAVF was found, which was fed by right radicular arteries from segmental artery at L2 level and drained retrogradely into perimedullary veins. A concomitant spinal extradural nodular fasciitis at right L1/L2 intervertebral foramen was also noted. The SDAVF was completely obliterated by endovascular treatment and the tumor was debulked. The patient recovered well after the procedures.

Conclusions

Our case report suggests SDAVF can occur in adolescent. The concomitant presence with a nodular fasciitis indicates that although it usually arises in subcutaneous tissue but can rarely form on the dura of spine.

Clinical and radiographic characteristics of sacral arteriovenous fistulas: a multicenter experience

OBJECTIVE

Available data on management of sacral arteriovenous fistulas (sAVFs) are limited to individual case reports and small series. Management includes observation, endovascular embolization, or surgical ligation, with no clear guidelines on the optimal treatment modality. The authors' objective was to report their multiinstitutional experience with management of sAVF patients, including clinical and radiographic characteristics and postprocedural outcomes.

METHODS

The electronic medical records of patients with a diagnosis of spinal arteriovenous fistula treated from January 2004 to December 2019 at the authors' institutions were reviewed, and data were summarized using descriptive statistics, including percentage and count for categorical data, median as a measure of central tendency for continuous variables, and interquartile range (IQR) as a measure of dispersion.

RESULTS

A total of 26 patients with sAVFs were included. The median (IQR) age was 65 (57-73) years, and 73% (n = 19) of patients were male. Lower-extremity weakness was the most common presenting symptom (n = 24 [92%]), and half the patients (n = 13 [50%]) reported bowel and bladder sphincter dysfunction. The median (IQR) time from symptom onset to treatment was 12 (5.25-26.25) months. Radiographically, all patients had T2 hyperintensity at the level of the conus medullaris (CM) (n = 26 [100%]). Intradural flow voids were identified in 85% (n = 22) of patients. The majority of the lesions had a single identifiable arterial feeder (n = 19 [73%]). The fistula was located most commonly at the S1 level (n = 13 [50%]). The site where the draining vein connects to the pial venous plexus was seen predominantly at the lumbar level (n = 16 [62%]). In total, 29 procedures were performed: 10 open surgeries and 19 endovascular embolization procedures. Complete occlusion was achieved in 90% (n = 9) of patients after open surgery and 79% (n = 15) after endovascular embolization. Motor improvement was seen in 68% of patients (n = 15), and bladder and bowel function improved in 9 patients (41%). At last follow-up, 73% (n = 16) of patients had either resolution or improvement of the pretreatment intramedullary T2 signal hyperintensity.

CONCLUSIONS

T2 hyperintensity of the CM and a dilated filum terminale vein are consistent radiographic signs of sAVF, and delayed presentation is common. Complete occlusion was achieved in almost all patients after surgery, and endovascular embolization was effective in 70% of the patients. Further studies are needed to determine the best treatment modality based on case-specific characteristics.

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.

Challenges in Diagnosis and Management of Previously Embolized Spinal Dural Arteriovenous Fistulae

BACKGROUND

Given the growing prevalence of initial endovascular treatment for type 1 spinal dural arteriovenous fistulae (dAVF), there are an increasing number of patients presenting with progressive symptoms related to recurrent previously embolized spinal dAVF. This study's goal was to identify demographic, clinical, and radiographic variables among patients who have failed embolization of type I spinal dAVF.

METHODS

A retrospective review of 24 consecutive surgeries for type I spinal dAVF performed by the senior author (A.D.L.) identified 5 patients who underwent open surgery for failed embolization. These 5 cases were reviewed for location of fistula, time from embolization to recurrence, preoperative functional status, fistulous point encountered at surgery, and clinical outcome of the patient at 3-month follow-up. A representative example case is reviewed in detail.

RESULTS

The median age at time of recurrence was 63 years (range 51-73 years). The median timing of embolization to recurrence of neurologic symptoms was 5 months (range 1-54) and to surgery 7 months (range 2-60 months). The level of the spinal dAVF was most frequently at T12-L1 (n = 3). Spinal magnetic resonance arteriography led to localization of the spinal dAVF in 2 patients and spinal catheter angiogram in 3 cases. All patients had definitive radiographic cure of the dAVF at last clinical follow-up.

CONCLUSIONS

The increased use of endovascular treatment of spinal dAVF has led to the treatment of refractory cases with a greater degree of surgical complexity. Open surgical ligation continues to provide the most definitive treatment outcomes for this complex spinal vascular entity.

Spinal vascular lesions: anatomy, imaging techniques and treatment

•

Vascular myelopathies include different aetiology and mechanism of damage.

•

The level of the lesion and the localization within the SC correlates with the clinical symptoms.

•

CT, MRI and angiography are essential for diagnosis and treatment playing a complementary role.

•

MRI is the gold standard for the evaluation of spinal cord lesions.

•

Spinal angiography is the gold standard for evaluation of spinal cord vasculature and vascular malformations.

Background

Vascular lesions of the spinal cord are rare but potentially devastating conditions whose accurate recognition critically determines the clinical outcome. Several conditions lead to myelopathy due to either arterial ischemia, venous congestion or bleeding within the cord. The clinical presentation varies, according with the different aetiology and mechanism of damage.

Purpose

The aim is to provide a comprehensive review on the radiological features of the most common vascular myelopathies, passing through the knowledge of the vascular spinal anatomy and the clinical aspects of the different aetiologies, which is crucial to promptly address the diagnosis and the radiological assessment.

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.

Nontraumatic Spinal Cord Compression: MRI Primer for Emergency Department Radiologists

The occurrence of acute myelopathy in a nontrauma setting constitutes a medical emergency for which spinal MRI is frequently ordered as the first step in the patient's workup. The emergency department radiologist should be familiar with the common differential diagnoses of acute myelopathy and be able to differentiate compressive from noncompressive causes. The degree of spinal cord compression and presence of an intramedullary T2-hyperintense signal suggestive of an acute cord edema are critical findings for subsequent urgent care such as surgical decompression. Importantly, a delay in diagnosis may lead to permanent disability. In the spinal canal, compressive myelopathy can be localized to the epidural, intradural extramedullary, or intramedullary anatomic spaces. Effacement of the epidural fat and the lesion's relation to the thecal sac help to distinguish an epidural lesion from an intradural lesion. Noncompressive myelopathy manifests as an intramedullary T2-hyperintense signal without an underlying mass and has a wide range of vascular, metabolic, inflammatory, infectious, and demyelinating causes with seemingly overlapping imaging appearances. The differential diagnosis can be refined by considering the location of the abnormal signal intensity within the cord, the longitudinal extent of the disease, and the clinical history and laboratory findings. Use of a compartmental spinal MRI approach in patients with suspected nontraumatic spinal cord injury helps to localize the abnormality to an epidural, intradural extramedullary, or intramedullary space, and when combined with clinical and laboratory findings, aids in refining the diagnosis and determining the appropriate surgical or nonsurgical management.Online supplemental material is available for this article.^©RSNA, 2019.

Outcomes following surgical versus endovascular treatment of spinal dural arteriovenous fistula: a systematic review and meta-analysis

Although surgical resection is associated with a complete cure in most cases of spinal dural arteriovenous fistulas (SDAVF), there has been an increasing trend towards embolisation. We performed a systematic review and meta-analysis comparing surgical resection with endovascular treatment in terms of success of treatment, rate of recurrence and complications. A literature search was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Strength of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation Working Group system. Surgical outcomes such as initial treatment failure, late recurrence, neurological improvement and complications were compared between the two approaches. We included 57 studies with 2029 patients, of which 32 studies with 1341 patients directly compared surgery (n=590) and embolisation (n=751). Surgery was found to be associated with significantly lower odds of initial treatment failure (OR: 0.15, 95% CI 0.09 to 0.24, I² 0%, p<0.001) and late recurrence (OR 0.18, 95% CI 0.09 to 0.39, I² 0%, p<0.001). The odds of neurological improvement following surgery were also significantly higher compared with embolisation alone (OR: 2.73, CI:1.67 to 4.48, I² :49.5%, p<0.001). No difference in complication rates was observed between the two approaches (OR 1.78, 95% CI 0.97 to 3.26, I² 0%, p=0.063). Onyx was associated with significantly higher odds of initial failure/late recurrence as compared with n-butyl 2-cyanoacrylate (OR: 3.87, CI: 1.73 to 8.68, I² :0%, p<0.001). Surgery may be associated with superior outcomes for SDAVFs in comparison to endovascular occlusion. Newer embolisation agents like Onyx have not conferred a significant improvement in occlusion rate.

Intraoperative angiography via the popliteal artery: a useful technique for patients in the prone position

OBJECTIVE Intraoperative angiography can be a valuable tool in the surgical management of vascular disorders in the CNS. This is typically accomplished via femoral artery puncture; however, this can be technically difficult in patients in the prone position. The authors describe the feasibility of intraoperative angiography via the popliteal artery in the prone patient. METHODS Three patients underwent intraoperative spinal angiography in the prone position via vascular access through the popliteal artery. Standard angiography techniques were used, along with ultrasound and a micropuncture needle for initial vascular access. Two patients underwent intraoperative angiography to confirm the obliteration of dural arteriovenous fistulas. The third patient required unexpected intraoperative angiography when a tumor was concerning for a vascular malformation in the cervical spine. RESULTS All 3 patients tolerated the procedure without complication. The popliteal artery was easily accessed without any adaptation to typical patient positioning for these prone-position cases. This proved particularly beneficial when angiography was not part of the preoperative plan. CONCLUSIONS Intraoperative angiography via the popliteal artery is feasible and well tolerated. It presents significant benefit when obtaining imaging studies in patients in a prone position, with the added benefit of easy access, familiar anatomy, and low concern for catheter thrombosis or kinking.

A practical approach to the diagnosis of spinal cord lesions

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