Spinal dural arteriovenous fistulas: recognizing the spectrum of magnetic resonance imaging findings

Spinal dural arteriovenous fistula: A rare cause of progressive myelopathy and bladder and bowel dysfunction

Spinal dural arteriovenous fistula (SDAVF) is a rarely seen vascular lesion in the spinal cord and is often overlooked. If left untreated in the early stages, it is associated with severe morbidity and may lead to progressive myelopathy and bladder and bowel dysfunction. A 55-year-old male patient was admitted with complaints of lower extremity weakness, gait disorder, urinary retention, and stool retention. Based on physical examination and magnetic resonance imaging findings, a preliminary diagnosis of SDAVF was made. The diagnosis was confirmed by spinal angiography showing SDAVF on the left T6. Microsurgery was planned, once endovascular embolization failed. Although symptoms of progressive myelopathy and bladder and bowel dysfunction are rarely seen, SDAVF diagnosis should not be overlooked, and it should be kept in mind that early diagnosis and treatment prevent severe morbidities.

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.

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.

Brainstem Congestion Due to Dural Arteriovenous Fistula at the Craniocervical Junction: Case Report and Review of the Literature

BACKGROUND

Dural arteriovenous fistulas (DAVFs) at the craniocervical junction are rare. Clinical manifestations range from acute or chronic myelopathy to subarachnoid hemorrhage to brainstem dysfunction. We encountered 4 cases of DAVFs at the craniocervical junction with progressive brainstem dysfunction and investigated the typical magnetic resonance imaging (MRI) features using T₂-weighting imaging, susceptibility-weighted imaging, diffusion-weighted imaging, and contrast-enhanced imaging. Literature review revealed 10 case reports of DAVFs at the craniocervical junction manifesting with brainstem dysfunction.

CASE DESCRIPTION

Four patients presented with DAVFs at the craniocervical junction with progressive brainstem dysfunction. Two patients underwent midline suboccipital craniotomy and C1 laminectomy, and 1 patient underwent transarterial endovascular embolization with Onyx 18 under general anesthesia. All neurologic deficits gradually improved after the operation. In the fourth case, the patient received conservative treatment and did not undergo any surgical procedure. MRI showed high signal intensity on T₂-weighted imaging, magnetic resonance angiography, and magnetic resonance venography. Abnormal dilated vessels and flow-void signs around the lesions were detected on susceptibility-weighted imaging and contrast-enhanced images. Two cases revealed no abnormalities and had improved neurological deficits than those showed on diffusion-weighted imaging.

CONCLUSIONS

Susceptibility-weighted imaging, diffusion-weighted imaging, or contrast-enhanced scanning should be used during MRI examination of patients with progressive brainstem dysfunction to differentiate DAVFs at the craniocervical junction from other diseases, such as glioma or infection. Prompt diagnosis using MRI is of great significance in producing good functional outcomes of the patients.

Sacral dural arteriovenous fistulas: a diagnostic and therapeutic challenge – single-centre experience of 13 cases and review of the literature

Background

Sacral dural arteriovenous fistulas (DAVFs) are rare vascular abnormalities of the spine characterised by slowly progressive symptoms that can mimic different myelopathy disorders.

Object

To report our single Institution experience with sacral DAVFs.

Methods

We retrospectively reviewed the clinical records of patients admitted from 1 January 2006 to 31 December 2016 with a diagnosis of sacral DAVFs, treated by endovascular embolisation or surgical clipping. Clinical presentation, imaging characteristics, treatment results and follow-up were analysed.

Results

We identify 13 patients with sacral DAVFs supplied by lateral sacral arteries. Clinical presentation was characterised by different degrees of motor weakness and sphincter disturbances. In all patients, spinal MRI showed spinal cord hyperintensities with enhancement and prominent perimedullary vessels. Selective internal iliac angiography was mandatory to identify the exact location of the fistula. A complete embolisation was achieved in eight patients performing a single endovascular embolisation and in three patients performing a single surgical disconnection: two patients required combined procedures. Follow-up imaging showed a complete resolution of the spinal cord hyperintensities in 81% of patients and a reduction of the intramedullary enhancement in 91%. Gait improvement was observed in 73% of patients, while remaining stable in 27%. Sphincter disturbances improved in 36% of patients and remained stable in 64%.

Conclusion

Awareness of sacral location of DAVFs is critical because standard spinal angiography will not identify sacral supplies, unless internal iliac arteries are properly examined. In our experience, the endovascular treatment show results comparable to surgery when the fistula point is correctly disconnected.

Endovascular and Surgical Treatment of Spinal Dural Arteriovenous Fistulas: Assessment of Post-treatment Clinical Outcome

Spinal dural arteriovenous fistulas (DAVFs) are the most commonly encountered vascular malformation of the spinal cord and a treatable cause of progressive para- or tetraplegia. It is an elusive pathology that tends to be under-diagnosed, due to lack of awareness among clinicians, and affects males more commonly than females, typically between the fifth and eighth decades. Early diagnosis and treatment may significantly improve outcome and prevent permanent disability and even mortality. The purpose of our retrospective, single-center study was to determine the long-term clinical and radiographic outcome of patients who have received endovascular or surgical treatment of a spinal DAVF. In particular, during a 6-year period (2009–2014) 14 patients with a spinal DAVF were treated at our department either surgically (n = 4) or endovascularly (n = 10) with detachable coils and/or glue. There was no recurrence in the follow-up period (mean: 36 months, range 3–60 months) after complete occlusion with the endovascular treatment (n = 9; 90%), while only one patient (10%) had residual flow both post-treatment and at 3-month follow-up. All four surgically treated patients (100%) had no signs of residual DAVF on follow-up magnetic resonance angiography (MRA) and/or angiography (mean follow-up period of 9 months). Since improvement or stabilization of symptoms may be seen even in patients with delayed diagnosis and substantial neurological deficits, either endovascular or surgical treatment is always justified.

Spinal Dural Arteriovenous Fistula: Imaging Features and Its Mimics

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

A rare case of spinal dural arteriovenous fistula

Spinal dural arteriovenous fistula (SDAVF) is a rare vascular malformation of the spine. Only a limited number of cases of SDAVF have been reported in the current literature. We describe the case of a 74 year old male who presented with gradually progressive bilateral lower extremity weakness and bladder dysfunction and was subsequently diagnosed with SDAVF affecting both the thoracic and lumbar spine. The patient later underwent embolization with some improvement in his neurologic symptoms.

Absence of abnormal vessels in the subarachnoid space on conventional magnetic resonance imaging in patients with spinal dural arteriovenous fistulas

Spinal dural arteriovenous fistula (DAVF) is an uncommon condition that can be difficult to diagnose. This often results in misdiagnosis and treatment delay. Although conventional MRI plays an important role in the initial screening for the disease, the typical MRI findings may be absent. In this article, the authors present a series of 4 cases involving patients with angiographically proven spinal DAVFs who demonstrated cord T2 prolongation on conventional MRI but without abnormal subarachnoid flow voids or enhancement. These cases suggest that spinal DAVF cannot be excluded in symptomatic patients with cord edema based on conventional MRI findings alone. Dynamic Gd-enhanced MR angiography (MRA) was successful in demonstrating abnormal spinal vasculature in all 4 cases. This limited experience provides support for the role of spinal MRA in patients with abnormal cord signal and symptoms suggestive of DAVF even when typical MRI findings of a DAVF are absent.

Myelopathy caused by spinal dural arterio-venous fistula after first lumbar vertebral body fracture - a case report -

Spinal dural arteriovenous fistula is a rare vascular lesion of the spinal cord associated with progressive myelopathy. Symptoms include progressive gait dysfunction, weakness, sensory loss, and bowel and bladder dysfunction. Because these symptoms overlap with other common causes of myelopathy and the disease is rare, spinal dural arteriovenous fistula is often not suspected and the time to diagnosis is long. We report the case of a 60-year-old woman who presented with progressive lower limb weakness and gait disturbance diagnosed as spinal dural arteriovenous fistula involving a fractured L1 vertebral body.

Neck and low back pain: neuroimaging

Spine imaging accounts for a major share of expenses related to neck and back pain. Improving image quality translates into better morphologic evaluation of the spine. Unfortunately, the morphologic abnormalities on spine imaging are common and nonspecific, obscuring the relevance to patient symptomatology. Furthermore, distinction between degenerative and age-related changes is not clear. The key is clinical correlation of imaging findings. This article presents a concise and illustrated discussion of spinal neuroimaging related to neck and back pain, with emphasis on degenerative disease.