Lateral Decubitus Digital Subtraction Myelography: Tips, Tricks, and Pitfalls

Diagnosis and Treatment of Spontaneous Intracranial Hypotension: Role of Epidural Blood Patching

Purpose of Review

This review focuses on the challenges of diagnosing and treating spontaneous intracranial hypotension (SIH), a condition caused by spinal CSF leakage. It emphasizes the need for increased awareness and advocates for early and thoughtful use of empirical epidural blood patches (EBPs) in suspected cases.

Recent Findings

SIH diagnosis is hindered by variable symptoms and inconsistent imaging results, including normal brain MRI and unreliable spinal opening pressures. It is crucial to consider SIH in differential diagnoses, especially in patients with connective tissue disorders. Early EBP intervention is shown to improve outcomes.

Summary

SIH remains underdiagnosed and undertreated, requiring heightened awareness and understanding. This review promotes proactive EBP use in managing suspected SIH and calls for continued research to advance diagnostic and treatment methods, emphasizing the need for innovative imaging techniques for accurate diagnosis and timely intervention.

Safety and efficacy of transvenous embolization of cerebrospinal fluid-venous fistula in patients with spontaneous intracranial hypotension

BACKGROUND

Transvenous embolization is a recent treatment strategy for cerebrospinal fluid-venous fistulas (CSFVF), which are associated with spontaneous intracranial hypotension (SIH).

METHODS

Participants were selected from a prospective database on patients with CSFVF that received transvenous Onyx embolization. All patients underwent a brain magnetic resonance imaging (MRI) before and after embolization with MRI follow-up performed at least 3 months after treatment. Clinical and MRI results after treatment were described.

RESULTS

Twenty-one consecutive patients (median age 63 years, IQR = 58-71; females: 15/21 = 71.5%) with 30 CSFVF were included. Most lesions were situated between T9 and L1 (19/30 = 63%), 70% were right-sided, and 38% of the patients had multiples fistulas. Embolization was successful in all cases. The mean MRI SIH score before and after treatment was 6 (±2.5) and 1.4 (±1.6), respectively (p < 0.0001). Twenty patients (90%) experienced improvement of their initial condition, of which 67% reported complete clinical recovery. The mean HIT-6 score decreased from 67 (±15) to 38 (±9) (p < 0.0001), the mean amount of monthly headache days from 23.5 (±10) and 3.2 (±6.6) (p < 0.0001), the visual assessment scale (VAS) for headache severity from 8 (±1.9) to 1.2 (±2) (p < 0.0001), and the mean VAS for perception quality of life improved from 2.6 (±2.5) to 8.6 (±1.8) (p < 0.0001). There were no major complications. The suspected rebound headache rate after treatment was 33%.

CONCLUSION

Transvenous embolization of CSFVF allowed high rates of clinical improvement with no morbidity related to the treatment.

Posterior Transdural Repair of a Spontaneous Ventral Thoracic Cerebrospinal Fluid Leak: 2-Dimensional Operative Video

Spontaneous intracranial hypotension is a rare but serious condition characterized by orthostatic headaches and a variety of neurological symptoms. 1,2 Spontaneous intracranial hypotension should be considered in all patients with new onset, daily, persistent headaches, and orthostatic symptoms. It is typically caused by spontaneous spinal cerebrospinal fluid (CSF) leaks. 1,2 Traditional first-line treatments include hydration, bedrest, epidural blood patches, and fibrin glue injections. However, refractory cases often require surgical intervention, especially those caused by a small ventral osteophyte, which is classified as a type 1 leak. 3-5 The small osteophyte causes a tear in the dura of the ventral canal, usually near the cervicothoracic junction. Diagnosis of these leaks is challenging because these small osteophytes can also occur asymptomatically, or patients may have several of them at multiple levels. Typically, dynamic myelography is needed for accurate localization due to the inadequacy of standard imaging. 6 This video details a young patient with refractory spontaneous intracranial hypotension from a type 1 spontaneous CSF leak, treated successfully using a posterior transdural surgical approach with spinal cord mobilization. Our video presentation outlines the surgical technique and provides an overview of this underdiagnosed condition. Our described approach offers direct visualization, suturing of the leak site, and a multilayer repair without the need for spinal fusion. It also avoids the morbidity to the neck, chest, and mediastinal structures that is at risk with lateral or anterior approaches. A combined intradural and extradural repair may enhance the durability of repair for ventral CSF leaks. The patient consented to the procedure. This operative video did not require Institutional Review Board approval as all patient information has been anonymized, ensuring no identifiable information is disclosed. The video is a single case that does not involve interventions or pose risks beyond standard care, adhering to ethical guidelines and institutional policies.

Identifying Patients with CSF-Venous Fistula Using Brain MRI: A Deep Learning Approach

BACKGROUND AND PURPOSE

Spontaneous intracranial hypotension is an increasingly recognized condition. Spontaneous intracranial hypotension is caused by a CSF leak, which is commonly related to a CSF-venous fistula. In patients with spontaneous intracranial hypotension, multiple intracranial abnormalities can be observed on brain MR imaging, including dural enhancement, "brain sag," and pituitary engorgement. This study seeks to create a deep learning model for the accurate diagnosis of CSF-venous fistulas via brain MR imaging.

MATERIALS AND METHODS

A review of patients with clinically suspected spontaneous intracranial hypotension who underwent digital subtraction myelogram imaging preceded by brain MR imaging was performed. The patients were categorized as having a definite CSF-venous fistula, no fistula, or indeterminate findings on a digital subtraction myelogram. The data set was split into 5 folds at the patient level and stratified by label. A 5-fold cross-validation was then used to evaluate the reliability of the model. The predictive value of the model to identify patients with a CSF leak was assessed by using the area under the receiver operating characteristic curve for each validation fold.

RESULTS

There were 129 patients were included in this study. The median age was 54 years, and 66 (51.2%) had a CSF-venous fistula. In discriminating between positive and negative cases for CSF-venous fistulas, the classifier demonstrated an average area under the receiver operating characteristic curve of 0.8668 with a standard deviation of 0.0254 across the folds.

CONCLUSIONS

This study developed a deep learning model that can predict the presence of a spinal CSF-venous fistula based on brain MR imaging in patients with suspected spontaneous intracranial hypotension. However, further model refinement and external validation are necessary before clinical adoption. This research highlights the substantial potential of deep learning in diagnosing CSF-venous fistulas by using brain MR imaging.

Cerebrospinal fluid-lymphatic fistula in a child with generalized lymphatic anomaly treated with targeted blood patch - a rare case report and review of the literature

Spontaneous intracranial hypotension may result in debilitating postural headaches and severe neurological symptoms due to secondary cerebellar sagging. The most common cause is the cerebrospinal fluid (CSF) leak within the spinal canal. Although previously reported in only a few cases, also paraspinal lymphatic malformations causing vertebral bone destruction may occasionally result in CSF leak to these pathological formations. Here, we present a case of a 9-year-old girl with generalized lymphatic anomaly (GLA) presenting with severe postural headache. Radiological imaging revealed a typical feature of cerebellar sagging. Myelography localized the CSF leakage into vertebral bodies of C7 and Th1, which both were partly involved in pathological paravertebral masses of known lymphatic anomaly, and from there along the right C8 nerve root sleeve into the anomaly. As the C8-nerve root could not be ligated due to the risk of significant neurological injury, we attempted image-guided targeted percutaneous epidural placement of a blood patch directly into the foramen at the affected level. The procedure resulted in obliteration of the fistula and regression of cerebellar sagging, with significant relief of symptoms. Although it is an extremely rare coincidence, patients with paraspinal lymphatic malformations may develop intraspinal CSF leak into these pathological formations. The present case report suggests that besides a direct surgical obliteration of the fistula and sacrificing the nerve root, a targeted percutaneous epidural blood patch may be a possible alternative in the case of a functionally important nerve root.

Intracranial findings in spontaneous intracranial hypotension: Does the severity of abnormalities correspond with certainty and/or multifocality of cerebrospinal fluid leaks?

BACKGROUND AND PURPOSE

Spontaneous intracranial hypotension (SIH) is caused by spinal cerebrospinal fluid (CSF) leaks. This study assessed whether the certainty and/or multifocality of CSF leaks is associated with the severity of intracranial sequelae of SIH.

MATERIALS AND METHODS

A retrospective review was completed of patients with suspected SIH that underwent digital subtraction myelogram (DSM) preceded by brain MRI. DSMs were evaluated for the presence or absence of a CSF leak, categorized both as positive/negative/indeterminate and single versus multifocal. Brain MRIs were assessed for intracranial sequelae of SIH based on two probabilistic scoring systems (Dobrocky and Mayo methods). For each system, both an absolute "numerical" score (based on tabulation of findings) and "categorized" score (classification of probability) were tabulated.

RESULTS

174 patients were included; 113 (64.9%) were female, average age 52.0 ± 14.3 years. One or more definite leaks were noted in 76 (43.7%) patients; an indeterminate leak was noted in 22 (12.6%) patients. 16 (16.3%) had multiple leaks. There was no significant difference in the severity of intracranial findings between patients with a single versus multiple leaks (p values ranged from .36 to .70 using categorized scores and 0.22-0.99 for numerical scores). Definite leaks were more likely to have both higher categorized intracranial scores (Mayo p = .0008, Dobrocky p = .006) and numerical scores (p = .0002 for Mayo and p = .006 for Dobrocky).

CONCLUSIONS

Certainty of a CSF leak on diagnostic imaging is associated with severity of intracranial sequelae of SIH, with definite leaks having significantly more intracranial findings than indeterminate leaks. Multifocal leaks do not cause greater intracranial abnormalities.

Spinal Cerebrospinal Fluid Leak Localization with Digital Subtraction Myelography: Tips, Tricks, and Pitfalls

Cerebrospinal fluid (CSF) leak can cause spontaneous intracranial hypotension (SIH) which can lead to neurologic symptoms, such as orthostatic headache. Over time, imaging techniques for detecting and localizing CSF leaks have improved. These techniques include computed tomography (CT) myelography, dynamic CT myelography, cone-beam CT, MRI, MR myelography, and digital subtraction myelography (DSM). DSM provides the highest sensitivity for identifying leak sites and has comparable radiation exposure to CT myelography. The introduction of the lateral decubitus DSM has proven invaluable in localizing leaks when other imaging tests have been inconclusive.

Endovascular Embolization Techniques for Cerebrospinal Fluid-Venous Fistula in the Treatment of Spontaneous Intracranial Hypotension

Cerebrospinal fluid-venous fistula (CVF) is an important cause of spontaneous intracranial hypotension (SIH), a condition characterized by low cerebrospinal fluid (CSF) volume and orthostatic headaches. The pathogenesis of CVF is thought to be direct connection of the spinal dura to one or more veins in the epidural space, allowing unregulated flow of CSF into the venous system. Herein, we provide a comprehensive review of the endovascular management of CVF in patients with SIH. We also focus on the various techniques and devices used in endovascular treatment, as well as the pathogenesis, diagnosis, and alternative treatment options of CVF.

Management of cervical CSF-venous fistula causing acute cognitive impairment and coma

CSF-venous fistulas (CVFs) are increasingly recognised as a cause of spontaneous intracranial hypotension. They may present atypically including with brain sagging pseudo-dementia. Cervical CVFs are rare and their management can be difficult due to associated eloquent nerve roots. We report the case of a 49-year-old woman who presented with cognitive decline progressing to coma. Brain imaging showed features of spontaneous intracranial hypotension and a right C7 CVF was identified at digital subtraction and CT myelography. Initial treatment with CT-guided injection of fibrin sealant produced temporary improvement in symptoms before surgical treatment resulted in total clinical remission and radiological resolution.

Lateral Decubitus Dynamic CT Myelography with Real-Time Bolus Tracking (dCTM-BT) for Evaluation of CSF-Venous Fistulas: Diagnostic Yield Stratified by Brain Imaging Findings

BACKGROUND AND PURPOSE

CSF-venous fistulas (CVFs) associated with spontaneous intracranial hypotension (SIH) may have a transient appearance, relative to contrast arrival, which may influence the diagnostic performance of lateral decubitus CT myelography (CTM). We developed a dynamic CTM protocol using real-time bolus-tracking (dCTM-BT) to improve the temporal resolution and standardize the timing of CTM acquisitions post-intrathecal contrast administration. The purpose of our study was to evaluate the feasibility of the dCTM-BT technique and evaluate its diagnostic yield for CVF detection, stratified by brain MRI SIH findings.

MATERIALS AND METHODS

Patients with suspected SIH without extradural fluid collection on spine MRI who underwent dCTM-BT were retrospectively reviewed. CT bolus monitoring was performed at the upper thoracic level. Following the visualization of dense intrathecal contrast, at least 3 CTM acquisitions of the spine were obtained and reviewed by 2 neuroradiologists. The Bern SIH score was calculated on the brain MRI. The diagnostic yield for CVF detection was evaluated, stratified by Bern score categories and a receiver operating characteristic (ROC) analysis.

RESULTS

Out of 48 patients, 23 (48%) had a CVF on dCTM-BT, located at T1-5 (n = 4), T6-12 (n = 18), L1 (n = 1), with 70% on the right. CVF was identified in 22/22 (100%) of patients who had a high Bern score, 1/7 (14%) of those who had an intermediate score, and 0/19 (0%) of those who had a low score. The area under the ROC curve was 0.99 (95% CI, 0.98-1.00). The optimal cutoff was a Bern score of ≥5 (96% sensitivity, 100% specificity).

CONCLUSIONS

dCTM-BT is feasible and has excellent diagnostic performance for CVF identification/localization. The Bern score is strongly associated with CVF detection and may help inform who will benefit from dCTM-BT.

Fluctuating hearing loss secondary to spontaneous intracranial hypotension: A case report and review of the literature

OBJECTIVE

Fluctuating sensorineural hearing loss (SNHL) has multiple etiologies, most commonly Ménière's disease (MD), recurrent sudden SNHL, and autoimmune inner ear disorders. Fluctuating SNHL has rarely been described as a symptom of spontaneous intracranial hypotension (SIH).

PATIENT

A 39-year-old previously healthy female presented with "Ménière's like" symptoms responsive to steroid treatment, which worsened during the day and improved in the supine position. Conservative treatment for MD consisting of low salt and caffeine diet and betahistine medication yielded no improvement. Secondary revision of brain imaging scans showed signs indicative of SIH, and a spinal cerebrospinal fluid leak was ultimately found and treated by a novel technique of transvenous fistula embolization by means of Onyx® glue, leading to gradual clinical improvement and near-complete resolution of symptoms.

CONCLUSION

SIH should be considered as part of the differential diagnosis of fluctuating SNHL. Clinical and radiological features should be known and sought. We suspect that early diagnosis and treatment can lead to cure and prevent permanent auditory damage.

Efficacy of transvenous embolization of CSF-venous fistula in spontaneous intracranial hypotension: Case-series

BACKGROUND

Spontaneous intracranial hypotension is a debilitating neurological condition which can be caused by a cerebrospinal fluid-venous fistula. Transvenous embolization is a promising technique to provide minimally invasive yet durable treatment.

METHODS

A retrospective single-center case series was performed on all patients who underwent transvenous embolization of a cerebrospinal fluid (CSF)-venous fistula. Clinical and radiographic parameters, including Bern score, were reported preoperatively and at 3-month follow-up.

RESULTS

Six patients underwent embolization of a CSF-venous fistula. All fistulae were located in the thoracic spine and technical success was achieved in all cases. Three patients had symptom resolution, two had significant improvement, and one had stable symptoms on follow-up. The mean Bern score was 6.83 (SD = 1.47) preoperatively and 1.83 (SD = 1.64) postoperatively with a mean improvement in Bern score of 5.0 (SD = 1.9, p = 0.0013).

CONCLUSIONS

CSF-venous fistulas are an increasingly recognized clinical entity which may be treated with transvenous embolization. This case series serves to further validate this technique and suggests it can be performed with similar outcomes in lower volume centers.

Direct comparison of digital subtraction myelography versus CT myelography in lateral decubitus position: evaluation of diagnostic yield for cerebrospinal fluid-venous fistulas

BACKGROUND

Cerebrospinal fluid (CSF)-venous fistulas (CVFs) are increasingly identified as a cause of spontaneous intracranial hypotension (SIH). Lateral decubitus digital subtraction myelography (LD-DSM) and CT myelography (LD-CTM) are mainly used for detection, but the most sensitive method is yet unknown.

OBJECTIVE

To compare LD-DSM with LD-CTM for diagnostic yield of CVFs.

METHODS

Patients with SIH diagnosed with a CVF between January 2021 and December 2022 in which the area of CVF(s) was covered by both diagnostic modalities were included. LD-CTM immediately followed LD-DSM without repositioning the spinal needle, and the second half of the contrast agent was injected at the CT scanner. Patients were awake or mildly sedated. Retrospectively, two neuroradiologists evaluated data independently and blinded for the presence of CVF.

RESULTS

Twenty patients underwent a total of 27 combined LD-DSM/LD-CTM examinations (4/20 with follow-up and 3/20 with bilateral examinations). Both raters identified significantly more CVFs with LD-CTM than with LD-DSM (rater 1: 39 vs 9, P<0.001; rater 2: 42 vs 12, P<0.001). Inter-rater agreement was substantial for LD-DSM (κ=0.732) and LD-CTM (κ=0.655). The results remained significant after considering the senior rating for cases of disagreement (39 vs 10; P<0.001), and no CVF detected on LD-DSM was missed on LD-CTM.

CONCLUSION

In this study, LD-CTM has a higher diagnostic yield for the detection of CVFs than LD-DSM and should supplement LD-DSM, but further studies are needed. LD-CTM can be easily acquired in awake or mildly sedated patients with the second half of contrast injected just before CT scanning, or it may be considered as a stand-alone investigation.

Likelihood of Discovering a CSF Leak Based on Intracranial MRI Findings in Patients without a Spinal Longitudinal Extradural Collection: A New Probabilistic Scoring System

BACKGROUND AND PURPOSE

The likelihood of discovering a CSF leak can be determined by assessing intracranial abnormalities. However, the Dobrocky scoring system, which is used to determine this likelihood, did not incorporate patients with CSF-venous fistulas. This study sought to create a new probabilistic scoring system applicable to patients without a spinal longitudinal extradural collection.

MATERIALS AND METHODS

A retrospective review was completed of patients with suspected spontaneous intracranial hypotension who underwent brain MR imaging followed by digital subtraction myelography with same-day CT myelography. Patients with and without leaks found on digital subtraction myelography were included. MRIs were assessed for numerous reported stigmata of spontaneous intracranial hypotension and were compared between cohorts.

RESULTS

One hundred seventy-four patients were included; 113 (64.9%) were women (average age, 52.0 [SD, 14.3] years). A CSF leak was found in 98 (56.3%) patients, nearly all of which (93.9%) were CSF-venous fistulas. Diffuse dural enhancement, internal auditory canals dural enhancement, non-Chiari cerebellar descent, pituitary engorgement, brain sag, dural venous sinus engorgement, and decreased suprasellar cistern size were associated with a CSF leak. A probabilistic scoring system was made in which a single point value was assigned to each of those findings: 0-2 considered low probability and ≥3 considered intermediate-to-high probability of a CSF leak.

CONCLUSIONS

This study offers a new probabilistic scoring system for evaluating the likelihood of discovering a CSF leak on the basis of intracranial MR imaging findings, though the new system is not superior to that of the Dobrocky method for predicting the presence of CSF leaks.

Clinical and imaging outcomes of 100 patients with cerebrospinal fluid-venous fistulas treated by transvenous embolization

BACKGROUND

Cerebrospinal fluid-venous fistulas (CSFVF) are a common cause of spontaneous intracranial hypotension (SIH). Transvenous embolization has emerged as a reliable treatment option. We review the clinical presentation, imaging, and clinical outcomes of 100 consecutive CSFVF patients who underwent embolization over 2 years.

METHODS

Baseline clinical characteristics, imaging findings (including Bern SIH score), technical outcomes, and long-term imaging and clinical outcomes were collected. All patients had at least 3 months of clinical follow-up and had baseline MRI. 99/100 patients underwent follow-up imaging at ≥3 months post-treatment.

RESULTS

100 patients were included. Mean imaging and clinical follow-up duration was 8.3±7.7 months and 15.0±6.8 months, respectively. The mean duration of symptoms before embolization was 40.9±52 months. Mean baseline Bern SIH score was 5.9±3.3. The most common baseline symptoms were headache (96 patients), tinnitus (55 patients), and cognitive dysfunction (44 patients). Technical success rate was 100%. Mean post-treatment Bern SIH score was 0.9±1.6 (P<0.0001). Following treatment, 95% of patients reported significant improvement or resolution in symptoms (58 patients reporting resolution and 37 reporting improvement). 5 patients reported no improvement. There were no major procedural or periprocedural complications. 10 patients had minor procedural complications that did not result in any change in management (Onyx emboli, venous perforation). 19 patients had rebound intracranial hypertension requiring acetazolamide therapy. 7 patients had recurrent fistula at the initially treated level.

CONCLUSIONS

Transvenous embolization of CSFVF in SIH patients is safe and effective with a 95% treatment response, significant improvement in imaging outcomes, and a very low rate of complications.

Incremental diagnostic yield and clinical outcomes of lateral decubitus CT myelogram immediately following negative lateral decubitus digital subtraction myelogram

INTRODUCTION

Spontaneous intracranial hypotension (SIH) caused by a spinal cerebrospinal fluid (CSF) leak classically presents with orthostatic headache. Digital subtraction myelography (DSM) has a well-established diagnostic yield in the absence of extradural spinal collection. At our institution, DSM is followed by lateral decubitus CT myelogram (LDCTM) in the same decubitus position to increase diagnostic yield of the combined study. We evaluated the incremental diagnostic yield of LDCTM following negative DSM and reviewed patient outcomes.

METHODS

Retrospective review of consecutive DSMs with subsequent LDCTM from April 2019 to March 2021 was performed. Combined reports were reviewed, and studies with positive DSMs were excluded. Of the exams with negative DSM, only studies with LDCTM reports identifying potential leak site were included. Interventions and follow-up clinical notes were reviewed to assess symptoms improvement following treatment.

RESULTS

Of the 83 patients with negative DSMs, 11 (13.2%) had positive leak findings on LDCTMs, and 21 (25.3%) were equivocal. Of 11 positive LDCTMs, 6 leaks were nerve sheath tears (NSTs) and 5 were CSF-venous fistulas (CVFs). 10/11 (90.9%) had intervention and follow-up, with 9/10 (90%) having positive clinical outcome. Of the 21 equivocal LDCTM patients (19 CVFs and 2 NSTs), 15 (71.4%) had interventions and follow-up, with 3/15 (20.0%) with positive clinical outcomes.

CONCLUSION

LDCTM following negative DSM has an incremental diagnostic yield up to 38.6%, with up to 14.5% of positive patient outcomes following treatment. LDCTM should be considered after DSM to maximize diagnostic yield of the combined exam.

Utility of Photon-Counting Detector CT Myelography for the Detection of CSF-Venous Fistulas

CSF-venous fistulas are an increasingly recognized type of CSF leak that can be particularly challenging to detect, even with recently improved imaging techniques. Currently, most institutions use decubitus digital subtraction myelography or dynamic CT myelography to localize CSF-venous fistulas. Photon-counting detector CT is a relatively recent advancement that has many theoretical benefits, including excellent spatial resolution, high temporal resolution, and spectral imaging capabilities. We describe 6 cases of CSF-venous fistulas detected on decubitus photon-counting detector CT myelography. In 5 of these cases, the CSF-venous fistula was previously occult on decubitus digital subtraction myelography or decubitus dynamic CT myelography using an energy-integrating detector system. All 6 cases exemplify the potential benefits of photon-counting detector CT myelography in identifying CSF-venous fistulas. We suggest that further implementation of this imaging technique will likely be valuable to improve the detection of fistulas that might otherwise be missed with currently used techniques.

Spontaneous intracranial hypotension due to CSF-venous fistula: Evaluation of renal accumulation of contrast following decubitus myelography and maintained decubitus CT to improve fistula localization

PURPOSE

Presented here is a strategy of sequential lateral decubitus digital subtraction myelography (LDDSM) followed closely by lateral decubitus CT (LDCT) to facilitate cerebrospinal fluid (CSF)-venous fistula (CVF) localization.

MATERIALS AND METHODS

This is a retrospective analysis of patients referred to our institution for evaluation of CSF leak. Patients with Type 1 and Type 2 leaks, and those not displaying MR brain stigmata of intracranial hypotension were excluded. All patients underwent consecutive LDDSM and LDCT. If the CVF was not localized on the first LDDSM-LDCT pair the patient returned for contralateral examinations. Images were reviewed for CVF and for accumulation of contrast within the renal pelvises expressed as a renal pelvis contrast score (RPCS) in Hounsfield units (HU).

RESULTS

Twenty-two patients were included in this study. In 21 of 22 patients (95%) a CVF was identified yielding an RPCS for the LDDSM-LDCT pair ipsilateral to the CVF ranging from 71 to 423 with an average of 146 HU. An RPCS of the negative side LDDSM-LDCT pair contralateral to a CVF was available in 8 patients and averaged 51 HU. In 4 patients the initial bilateral LDDSM-LDCT pairs did not reveal the location of the CVF however in 3 of these 4 cases the CVF was revealed on a third LDDSM repeated ipsilateral to the higher RPCS.

CONCLUSION

The strategy of sequential LDDSM-LDCT coupled with evaluation of renal accumulation of contrast agent appears to improve the rate of CVF localization and warrants further evaluation.

The clue is in the kidneys: greater renal contrast medium accumulation on ipsilateral side down CT myelogram after lateral decubitus digital subtraction myelogram as a predictor of laterality of cerebrospinal fluid leak

AIM

To assess the potential correlation of the laterality of a cerebrospinal fluid (CSF)-venous fistula with the laterality of decubitus computed tomography (CT) myelogram (post decubitus digital subtraction myelogram) based on which side demonstrated more renal contrast medium excretion.

MATERIALS AND METHODS

Patients with CSF-venous fistulas diagnosed at lateral decubitus digital subtraction myelograms were reviewed retrospectively. Patients who did not have CT myelogram following one or both left and right lateral decubitus digital subtraction myelograms were excluded. Two neuroradiologists independently interpreted the CT myelogram for the presence or absence of renal contrast, and whether subjectively more renal contrast medium was visualised on the left or right lateral decubitus CT myelogram.

RESULTS

Renal contrast medium was seen in lateral decubitus CT myelograms in 28 of 30 (93.3%) patients with CSF-venous fistulas. Having more renal contrast medium in right lateral decubitus CT myelogram was 73.9% sensitive and 71.4% specific for the diagnosis of a right-sided CSF-venous fistula, whereas having more renal contrast medium in the left lateral decubitus CT myelogram was 71.4% sensitive and 82.6% specific for a left-sided CSF-venous fistula (p=0.02).

CONCLUSION

When the CSF-venous fistula lies on the dependent side of a decubitus CT myelogram performed after decubitus digital subtraction myelogram, relatively more renal contrast medium is visualised compared to when the fistula lies on the non-dependent side.

Temporal Characteristics of CSF-Venous Fistulas on Digital Subtraction Myelography

BACKGROUND AND PURPOSE

CSF-venous fistula can be diagnosed with multiple myelographic techniques; however, no prior work has characterized the time to contrast opacification and the duration of visualization. The purpose of our study was to evaluate the temporal characteristics of CSF-venous fistula on digital subtraction myelography.

MATERIALS AND METHODS

We reviewed the digital subtraction myelography images of 26 patients with CSF-venous fistulas. We evaluated how long the CSF-venous fistula took to opacify after contrast reached the spinal level of interest and how long it remained opacified. Patient demographics, CSF-venous fistula treatment, brain MR imaging findings, CSF-venous fistula spinal level, and CSF-venous fistula laterality were recorded.

RESULTS

Eight of the 26 CSF-venous fistulas were seen on both the upper- and lower-FOV digital subtraction myelography, for a total of 34 CSF-venous fistula views evaluated on digital subtraction myelography. The mean time to appearance was 9.1 seconds (range, 0-30 seconds). Twenty-two (84.6%) of the CSF-venous fistulas were on the right. The highest fistula level was C7, while the lowest was T13 (13 rib-bearing vertebral bodies). The most common CSF-venous fistula levels were T6 (4 patients) followed by T8, T10, and T11 (3 patients each). The mean age was 58.3 years (range, 31.7-87.6 years). Sixteen patients were women (61.5%).

CONCLUSIONS

This is the first study to report the temporal characteristics of CSF-venous fistulas using digital subtraction myelography. We found that on average, the CSF-venous fistula appeared 9.1 seconds (range, 0-30 seconds) after intrathecal contrast reached the spinal level.

Conebeam CT as an Adjunct to Digital Subtraction Myelography for Detection of CSF-Venous Fistulas

Lateral decubitus digital subtraction myelography is an effective technique for precisely localizing CSF-venous fistulas, a common cause of spontaneous intracranial hypotension. However, despite an optimal imaging technique, digital subtraction myelography fails to identify some CSF-venous fistulas for a variety of reasons. Here, we describe a technique involving conebeam CT performed during intrathecal contrast injection as an adjunct to digital subtraction myelography, allowing identification of some otherwise-missed CSF-venous fistulas.

Presentation, Diagnosis, and Management of Lower Back Pain Associated with Spinal Stenosis: A Narrative Review

Lower back pain (LBP) is an extremely common symptom experienced by people of all ages and is also one of the most frequent causes of disability worldwide. This article aims to review the presentation, diagnosis, and management of lower back pain associated with spinal stenosis. The paper we prepared was classified as a "literature narrative review." Nonetheless, when searching for manuscripts included in our work and reviewing them critically, we concentrated on the keywords: "lower back pain", "lumbar spine stenosis", "diagnostic", "rehabilitation", "neurosurgery", "spine", and "elderly". The incidence of chronic lower back pain (CLBP) increases linearly starting with the third decade of life until 60 years old, and it more often affects women. The course of non-specific LBP above all depends on factors not connected with the spine, which include psychological, behavioral, and social factors, determined by the way the condition is perceived by the patient the environment. Lumbar spine stenosis (LSS) is an age-related process of degeneration of the intervertebral discs, ligamentum flavum, and facet joints, which results in narrowing of the space around the neurovascular structures of the spine. Diagnosis of spinal pain syndromes includes radiography (RTG), computed tomography (CT), and magnetic resonance imaging (MRI). Based on the results of imaging studies, neurological examination, and the severity of the disease, treatment can consist of analgesics and rehabilitation, or, when conservative methods are insufficient, surgical treatment is indicated.

[Spontaneous dural CSF fistula as a cause of intracranial hypotension syndrome. Case report and literature review]

Typical symptoms of spontaneous intracranial hypotension syndrome are severe headache, weakness, dizziness and inability to stay upright for a long time. Most often, this syndrome occurs due to CSF fistula in spinal space. Pathophysiology and diagnosis of this disease are poorly known for neurologists and neurosurgeons that can complicate timely surgical care. In case of correct diagnosis, we can identify the exact location of CSF fistula in 90% of cases. Treatment eliminates symptoms of intracranial hypotension and provides functional recovery. The purpose of this article is to describe the diagnostic algorithm and successful microsurgical treatment of a patient with spinal dural CSF fistula Th3-Th4 through posterolateral transdural approach.

Spinal dural cerebrospinal fluid fistula as a cause of spontaneous intracranial hypotension syndrome: Diagnosis and surgical treatment

Spontaneous intracranial hypotension (SIH) syndrome most often occurs following a cerebrospinal fluid (CSF) fistula that develops in the spinal space. Neurologists and neurosurgeons lack an understanding of the pathophysiology and diagnosis of this disease, which can make timely surgical care difficult. With the correct diagnostic algorithm, it is possible to identify the exact location of the liquor fistula in 90% of cases; subsequent microsurgical treatment can save the patient from the symptoms of intracranial hypotension and restore the ability to work. Female patient, 57 years old, was admitted with SIH syndrome. Magnetic resonance imaging (MRI) of the brain with contrast confirmed signs of intracranial hypotension. Computed tomography (CT) myelography was performed to pinpoint the location of the CSF fistula. The diagnostic algorithm and successful microsurgical treatment of a patient with spinal dural CSF fistula at the Th3-4 level using a posterolateral transdural approach. The patient was discharged on day 3 after the surgery when these complaints regressed completely. At the control examination of the patient 4 months postoperatively, there were no complaints. Identification of the cause and location of spinal the CSF fistula is a complex process that requires several stages of diagnosis. Examination of the entire back with MRI, CT myelography, or subtraction dynamic myelography is recommended. Microsurgical repair of a spinal fistula is an effective method for the treatment of SIH. The posterolateral transdural approach is effective in the repair of a spinal CSF fistula located ventrally in the thoracic spine.

Sacral CSF-Venous Fistulas and Potential Imaging Techniques

This is the first study to describe CSF-venous fistulas involving the sacrum, a location that may be underrecognized on the basis of current imaging techniques. We describe a delayed decubitus flat CT myelogram technique that may be useful to identify sacral CSF-venous fistulas.

Resisted Inspiration: A New Technique to Aid in the Detection of CSF-Venous Fistulas

We describe a technique termed "resisted inspiration" that could be used during myelography to decrease superior vena cava venous pressure and increase lumbar CSF pressure, potentially aiding in the detection of CSF-venous fistulas.

Utility of Dual-Energy CT to Improve Diagnosis of CSF Leaks on CT Myelography following Lateral Decubitus Digital Subtraction Myelography with Negative Findings

CSF leaks, including CSF-venous fistulas, which cause spontaneous intracranial hypotension, remain difficult to diagnose, even on digital subtraction myelography and CT myelography. Dual-energy CT technology has been used to improve diagnostic utility within multiple organ systems. The capability of dual-energy CT to create virtual monoenergetic images can be leveraged to increase conspicuity of contrast in CSF-venous fistulas and direct epidural CSF leakage to improve the diagnostic utility of CT myelography. Six cases (in 5 patients) are shown in which virtual monoenergetic images demonstrate a leak location that was either occult or poorly visible on high- or low-kilovolt series. This clinical report describes the novel application of dual-energy CT for the detection of subtle CSF leaks including CSF-venous fistulas.

Current perspectives on the recognition and diagnosis of low CSF pressure headache syndromes

INTRODUCTION

Headaches occur when cerebrospinal fluid (CSF) pressure drops following dural puncture or trauma or spontaneously. As the features of these headaches and their accompanying symptoms might not be typical, low CSF pressure headache syndromes, and spontaneous intracranial hypotension in particular, are often misdiagnosed and underdiagnosed.

AREAS COVERED

The aim of this narrative review is to summarize the most recent evidence regarding the clinical presentation and the diagnosis of low CSF pressure headache syndromes.

EXPERT OPINION

The clinical spectrum low CSF pressure headache syndromes varies significantly and key signs might be missing. Low CSF pressure headache syndromes should be included in the differential diagnosis of any case of refractory headache, even when the headache is not orthostatic, or there are normal neuroimaging findings, and/or lumbar puncture opening pressure is within normal limits. Future research should focus on controlled interventional studies on the treatment of low CSF pressure headache syndromes, which are currently lacking.

Imaging, Clinical, and Demographic Differences in Patients With Type III Spinal Cerebrospinal Fluid Leak (Cerebrospinal Venous Fistulas) Compared With Patients With Types I and II Spinal Cerebrospinal Fluid Leak

OBJECTIVE

Spinal cerebrospinal fluid (CSF) leaks are an underdiagnosed cause of neurologic symptoms. The most common types of spinal CSF leaks are from dural tears (type I) and meningeal diverticula (type II). Cerebrospinal fluid-venous fistulas (type III) are less common and underrecognized. The purpose of this study was to evaluate the intracranial and spinal imaging findings in patients with types I/II versus type III leaks.

MATERIALS AND METHODS

This was a retrospective, institutional review board-approved study performed on adult patients between January 2020 to September 2021 with surgically confirmed type I/II/III spinal CSF leak. Patients had preoperative brain magnetic resonance imaging (MRI) with contrast and medical records detailing symptoms and clinical diagnoses. Patients were excluded for nondiagnostic brain MRIs. Demographic and clinical information were recorded. The presence of extra-axial collections, pachymeningeal thickening, brain sagging, and decreased pontomamillary distance were evaluated on MRI.

RESULTS

Seven patients had type III leaks, and 16 had type I/II leaks. Patients with type III leaks were older (P = 0.0003) and had higher rates of initial misdiagnosis (100% vs 31%) and longer times to correct diagnosis (P = 0.03) compared with type I/II leaks. Intracranial extra-axial collections were never seen with type III leaks but were seen in 50% of type I/II leaks. Pachymeningeal thickening and brainstem sagging occurred in nearly equal frequency between groups. Smaller pontomamillary distances were seen in type III leaks versus type I/II leaks (P = 0.047).

CONCLUSIONS

When evaluating patients with suspected spinal CSF leak, findings of older age, absence of intracranial extra-axial collections, and small pontomamillary distances may raise suspicion for type III versus type I/II leak.

CSF-venous leak responsible for spontaneous intracranial hypotension treated by endovascular venous route: First cases in Italy

Spontaneous intracranial hypotension (SIH) is due to a leakage of CSF lowering the pressure of subarachnoid space, mostly caused by a dural breach or discogenic microspur. Clinical and MRI are usually typical enough to allow diagnosis, while finding the location of the dural breach is challenging. Since some years, CSF venous fistulas have been described as the cause of SIH, and a specific diagnostic and therapeutic path has been proposed. Here we report the first two successfully treated patients in Italy. Both had chronic and non specific symptoms, with severe reduction of quality of life; clinical symptoms improved after endovascular occlusion of the responsible vein.

Spontaneous Spinal CSF Leaks Stratified by Age, Body Mass Index, and Spinal Level

BACKGROUND AND PURPOSE

There are 3 main types of spinal CSF leaks, and the imaging appearances are well-reported. Specific patient demographics and spinal locations of the various types of spinal leaks are less frequently described. The purpose of this article was to stratify the various types of spontaneous CSF leaks on the basis of age, body mass index, and spinal level.

MATERIALS AND METHODS

Retrospective review was performed for all patients with spontaneous spinal CSF leaks identified on CT myelography. Age, body mass index, and spinal CSF leak type and level were recorded.

RESULTS

Sixty-five patients (37 women and 28 men) had spinal CSF leaks. Type 1 CSF leaks (dural tears) were observed in 25 patients (mean age, 44.5 years; mean body mass index, 24.3) and were most common in the upper thoracic spine (72%), particularly at the T1-T2 level (36%). Type 2 CSF leaks (ruptured meningeal diverticula) were observed in 4 patients (mean age, 45.5 years; mean body mass index, 27.5) and were all seen in the lower thoracic spine. Type 3 CSF leaks (CSF-venous fistulas) were observed in 36 patients (mean age, 58.8 years; mean body mass index, 27.0) and were most common on the right side (72%) and in the lower thoracic spine (56%).

CONCLUSIONS

Type 1 CSF leaks occurred in younger patients with a normal body mass index, while patients with type 3 CSF leaks were relatively older and had an elevated body mass index. Type 1 leaks mostly occurred in the upper thoracic spine, and types 2 and 3 leaks mostly occurred in the lower thoracic spine.

Combined CSF-venous Fistula and middle meningeal artery embolization for treatment of spontaneous intracranial hypotension

Transvenous Onyx embolization was recently described as an effective treatment of spontaneous intracranial hypotension caused by CSF-venous fistulas. Patients with CSF-venous fistulas can present with a wide spectrum of clinical and imaging findings, sometimes including spontaneous subdural hematomas, subdural hygromas, or a combination of both. Here, we describe four patients with spontaneous intracranial hypotension complicated by subdural fluid collections caused by CSF-venous fistulas. The patients were treated with transvenous Onyx embolization of their CSF-venous fistulas and transarterial particle embolization of the bilateral middle meningeal arteries, with both procedures performed in a single treatment session. All four patients had clinical improvement and decreased size or resolution of their subdural fluid collections. Based on our findings, we believe that middle meningeal embolization could be a useful adjunct to CSF-venous fistula embolization. A case-control study comparing patients who did or did not undergo middle meningeal embolization will be necessary to validate this supposition.

Same-Day Bilateral Decubitus CT Myelography for Detecting CSF-Venous Fistulas in Spontaneous Intracranial Hypotension

Lateral decubitus CT myelography is a sensitive technique for detecting CSF-venous fistulas in patients with spontaneous intracranial hypotension. It might be necessary to perform bilateral studies to locate a fistula. We report on the feasibility of obtaining diagnostic-quality bilateral decubitus CT myelography in a single session, avoiding the need to schedule separate examinations for the left and right sides on different days.

Clinical and imaging outcomes of cerebrospinal fluid-venous fistula embolization

Background

We report outcomes of spontaneous intracranial hypotension (SIH) patients who underwent transvenous embolization of cerebrospinal fluid-venous fistulas (CSFVFs) confirmed on digital subtraction myelography (DSM) performed at our institution.

Methods

This is a retrospective evaluation of a prospectively collected database of SIH patients who underwent transvenous embolization of CSFVFs. Only patients who had fistulas confirmed on DSM performed at our institution were included. All patients had a baseline MRI and an MRI performed at least 90 days post-embolization, as well as clinical evaluation using the six item Headache Impact Test (HIT-6) and the Patient Global Impression of Change (PGIC) scales. Paired t-test was used to report changes in Bern MRI scores and HIT-6 scores at follow-up.

Results

40 patients were included (29 female, 11 male). Mean age was 57.4±10.3 years. Mean Bern score improved from 5.7±3.0 at baseline to 1.3±2.0 at follow-up (p<0.0001). Mean HIT-6 score at baseline was 67.2±11.1 and at follow-up was 41.5±10.1 (p<0.0001). Median PGIC was 1, with 36 patients (90.0%) reporting at least minimal improvement and 32 patients (82.5%) reporting much or very much improvement. Complications included persistent local site pain in 12 patients (30%), suspected rebound intracranial hypertension requiring medical intervention in 7 patients (17.5%), and asymptomatic tiny Onyx emboli to the lungs in 3 patients (7.5%).

Conclusions

Transvenous embolization of CSFVFs using Onyx is safe and effective, resulting in significant improvement in headache and overall clinical outcomes in nearly 90% of patients, and substantial improvements in brain MRI abnormalities.

[Spinal CSF-venous fistula: case report and literature review]

Syndrome of spontaneous intracranial hypotension is increasingly described in the literature as a multifactorial disease with impairment of the quality of life and risk of mortality. CSF-venous fistula as a cause of intracranial hypotension syndrome is extremely rare and requires complex diagnosis and timely surgical treatment.

OBJECTIVE

We present a 55-year-old patient with acute spontaneous intracranial hypotension and spinal CSF-venous fistula. Literature data are also analyzed.

RESULTS

Algorithm for diagnosis and efficacy of microsurgical resection of CSF-venous fistula is demonstrated.

CONCLUSION

Intracranial hypotension following spinal fistula requires careful examination. Accurate understanding of pathophysiological and anatomical features of this disease is necessary to select an effective treatment method.

Spontaneous intracranial hypotension: the role of radiology in diagnosis and management

Spontaneous intracranial hypotension (SIH) is a condition that results from leakage of cerebrospinal fluid (CSF) from the spine, and which typically presents with debilitating orthostatic headache, but can be associated with a wide range of other symptoms. The causes of spontaneous CSF leaks that lead to SIH include dural tears, leaking meningeal diverticula, and CSF-venous fistulas. Imaging plays a central role in the initial diagnosis of SIH and in its subsequent investigation and management. This article reviews the typical neuroimaging manifestations of SIH and discusses the utility of different myelographic techniques for localising spinal CSF leaks as well as the role of image-guided treatment.

Post-dural puncture pseudomeningocele ("arachnoid bleb"): An underrecognized etiology of spontaneous intracranial hypotension symptomatology

Spontaneous intracranial hypotension (SIH) is an important secondary cause of a persistent headache syndrome, classically presenting as sudden onset debilitating positional headaches related to reduced intracranial cerebrospinal fluid (CSF) volume. Current understanding of SIH pathogenesis recognizes three underlying etiologies: dural tear, meningeal diverticulum, and CSF-venous fistula, with a fourth broad category of indeterminate/unknown etiologies. Post-dural puncture headache (PDPH) is a well-known and common complication of dural puncture, typically remitting spontaneously within two weeks of onset or with autologous epidural blood patch, though with some patients developing complex and difficult to manage chronic PDPH. Herein, we present a case of chronic PDPH resulting in SIH symptomatology secondary to a post-dural puncture pseudomeningocele, or "arachnoid bleb," successfully treated with curative surgical intervention. Increasing awareness of additional potential etiologies of SIH symptomatology will allow for improved detection for targeted definitive therapy, ultimately improving patient outcomes including quality of life in this debilitating and difficult to manage secondary headache syndrome.

Spontaneous intracranial hypotension: diagnostic and therapeutic workup

Spontaneous intracranial hypotension (SIH) is an orthostatic headache syndrome with typical MRI findings among which engorgement of the venous sinuses, pachymeningeal enhancement, and effacement of the suprasellar cistern have the highest diagnostic sensitivity. SIH is in almost all cases caused by spinal CSF leaks. Spinal MRI scans showing so-called spinal longitudinal extradural fluid (SLEC) are suggestive of ventral dural tears (type 1 leak) which are located with prone dynamic (digital subtraction) myelography. As around half of the ventral dural tears are located in the upper thoracic spine, additional prone dynamic CT myelography is often needed. Leaking nerve root sleeves typically associated with meningeal diverticulae (type 2 leaks) and CSF-venous fistulas (type 3 leaks) are proven via lateral decubitus dynamic digital subtraction or CT myelography: type 2 leaks are SLEC-positive if the tear is proximal and SLEC-negative if it is distal, and type 3 leaks are always SLEC-negative. Although 30–70% of SIH patients show marked improvement following epidural blood patches applied via various techniques definite cure mostly requires surgical closure of ventral dural tears and surgical ligations of leaking nerve root sleeves associated with meningeal diverticulae or CSF-venous fistulas. For the latter, transvenous embolization with liquid embolic agents via the azygos vein system is a novel and valuable therapeutic alternative.

Diagnostic Yield of Intrathecal Gadolinium MR Myelography for CSF Leak Localization

PURPOSE

Intrathecal gadolinium magnetic resonance (MR) myelography can be used to localize various types of spinal cerebrospinal fluid (CSF) leaks; however, its diagnostic yield is not well known. We sought to determine the diagnostic yield of MR myelography in patients with spontaneous intracranial hypotension.

METHODS

A retrospective review was performed on all patients who had undergone intrathecal gadolinium MR myelography at our institution from 2002 to 2020 for suspected spinal CSF leak. The MR myelography images were reviewed for the presence or absence of a spinal CSF leak site. Images were also evaluated for the presence an extradural fluid collection.

RESULTS

A total of 97 patients were included in the final cohort. The average age was 52.6 years; 67.0% were female, 4 patients underwent 2 examinations each, yielding a total of 101 MR myelograms. The source of a spinal CSF leak was localized in 14 patients. The diagnostic yield for CSF leak localization on intrathecal gadolinium MR myelography was 14/101 (13.9%) per GdM examination and 14/97 (14.4%) per patient. Among the subset of patients without extradural fluid collections, the yield was 15.7% per examination. All detected leaks were either CSF-venous fistulas or distal nerve root sleeve tears.

CONCLUSION

Intrathecal gadolinium MR myelography is capable of localizing CSF-venous fistulas and distal nerve root sleeve tears; however, our data show that it has a limited diagnostic yield. We suggest that other modalities may be a better first step before attempting intrathecal gadolinium MR myelography.

CSF-Venous Fistulas: Anatomy and Diagnostic Imaging

CSF-venous fistulas (CVFs), first described in 2014, represent an important cause of spontaneous intracranial hypotension (SIH). CVFs can be challenging to detect on conventional anatomic imaging because, unlike other types of spinal CSF leak, they do not typically result in pooling of fluid in the epidural space, and imaging signs of CVF may be subtle. Specialized myelographic techniques have been developed to help with CVF identification, but these techniques are not yet widely disseminated. This article reviews the current understanding of CVFs, emphasizing correlations between venous anatomy and imaging findings as well as potential mechanisms for pathogenesis, and describes current imaging techniques used for CVF diagnosis and localization. These techniques are broadly classified into fluoroscopy-based methods, including digital subtraction myelography and dynamic myelography, as well as cross-sectional methods, including decubitus CT myelography and MR myelography with intrathecal gadolinium. Knowledge of these various options, including their relative advantages and disadvantages, is critical in the care of patients with SIH. Investigation is ongoing, and continued advances are anticipated in understanding of CVFs as well as in optimal imaging detection.

Spontaneous Intracranial Hypotension in the Critical Patient

Spontaneous intracranial hypotension typically manifests with orthostatic headaches and is caused by spinal dural tears, ruptured meningeal diverticula, or CSF-venous fistulas. While most patients are diagnosed and treated in the outpatient setting, some patients will occasionally present in the emergent ICU setting due to subdural hematomas, coma, or downward brain herniation. In this review paper, we will discuss the diagnostic and treatment steps that intensivists can undertake to coordinate a team approach to successfully manage these patients. A brief general overview of spontaneous intracranial hypotension will also be discussed.

Headache Emergencies

Headache is a common reason for seeking medical attention. Most cases are benign primary headache disorders; however, there is significant overlap between symptoms of these disorders and secondary headaches. Differentiating these clinical scenarios requires a careful history with attention to red flag symptoms and a neurologic examination. These details can identify dangerous disorders: subarachnoid hemorrhage, reversible cerebral vasoconstriction syndrome, elevated intracranial pressure, hydrocephalus, cerebral venous sinus thrombosis, arterial dissection, central nervous system infection, and inflammatory vasculitis. Older, pregnant, or immunocompromised patients have a higher risk for secondary disorders; clinicians should have a different threshold to conduct evaluations in such patients.

A Novel Endovascular Therapy for CSF Hypotension Secondary to CSF-Venous Fistulas

We report a consecutive case series of patients who underwent transvenous embolization of the paraspinal vein, which was draining the CSF-venous fistula, for treatment of spontaneous intracranial hypotension. These are the first-ever reported cases of this treatment for CSF-venous fistulas. All patients underwent spinal venography following catheterization of the azygous vein and then selective catheterization of the paraspinal vein followed by embolization of the vein with Onyx. All patients had improvement of clinical and radiologic findings with 4 patients having complete resolution of headaches and 1 patient having 50% reduction in headache symptoms. Pachymeningeal enhancement resolved in 4 patients and improved but did not resolve in 1 patient. Brain sag resolved in 4 patients and improved but did not resolve in 1 patient. There were no cases of permanent neurologic complications. All patients were discharged home on the day of the procedure.

The importance of repeat digital subtraction myelography in the diagnosis of cryptogenic CSF-venous fistula causing spontaneous intracranial hypotension

Spontaneous intracranial hypotension (SIH) is a rare disorder that occurs secondary to acquired cerebrospinal fluid (CSF) leaks in the spine. Treatment involves either an epidural blood patch or surgical ligation. Essential to the selecting the optimal management strategy is classifying the type of leak and accurate localization of its level. Hitherto, this has been achieved using conventional imaging methods such as static CT or MR myelography which are adequate for the demonstration of only high flow leaks. Digital subtraction myelography (DSM) is a novel technique which provides superior temporal and spatial resolution in the localization of more challenging slow flow leaks. However, DSM may also be initially non-diagnostic. We report a case of SIH in which repeat DSM revealed a type 3 CSF-venous fistula and demonstrate a possible mechanism of transient CSF leak block resulting in the initial false negative findings based on morphological changes in the culprit nerve sheath diverticulum-pseudomeningocoele complex. The patient underwent successful surgical ligation with clinicoradiological resolution of SIH.

CSF-Venous Fistula

PURPOSE OF REVIEW

To provide an update on recent developments in the understanding, diagnosis, and treatment of CSF-venous fistula (CVF).

RECENT FINDING

CVF is a recently recognized cause of spontaneous intracranial hypotension (SIH), an important secondary headache, in which an aberrant connection is formed between the spinal subarachnoid space and an adjacent spinal epidural vein permitting unregulated loss of CSF into the circulatory system. CVFs often occur without a concurrent epidural fluid collection; therefore, CVF should be considered as a potential etiology for patients with SIH symptomatology but without an identifiable CSF leak. Imaging plays a critical role in the detection and localization of CVFs, with a number of imaging techniques and provocative maneuvers described in the literature to facilitate their localization for targeted and definitive treatment. Increasing awareness and improving the localization of CVFs can allow for improved outcomes in the SIH patient population. Future prospective studies are needed to determine the diagnostic performance of currently available imaging techniques as well as their ability to inform workup and guide treatment decisions.