Spontaneous intracranial hypotension: diagnostic and therapeutic workup

Safety, Sequelae, and Efficacy of Nerve Root Clipping in Patients With Spontaneous Spinal Cerebrospinal Fluid Leaks

BACKGROUND AND OBJECTIVES

Spinal cerebrospinal fluid (CSF) leaks may cause a myriad of clinical symptoms, the most common being orthostatic headache. Lateral leaks (Type II) and direct CSF-venous fistulas (Type III) are a subgroup of spinal CSF leaks, representing about 1/3 of spinal CSF leaks. This study aimed to analyze the risk and efficacy of nerve root clipping in patients with Type II and Type III CSF leaks.

METHODS

All consecutive patients with Type II and Type III CSF fistulas treated with nerve root clipping at our institution from May 2018 to December 2022 were included. Patients were evaluated for postoperative sensory motor deficits and neuropathic pain using the "Douleur Neuropathique 4" questionnaire, and the outcome was evaluated using the "Patient Global Impression of Change" and the return-to-work rate.

RESULTS

A total of 40 patients were included, and the mean follow-up time was 22 months. According to the Patient Global Impression of Change, significant symptoms improvement was reported in 85% of patients. Over 87% of patients returned to work fully or partially. One patient experienced a low-grade motor deficit after T1-nerve root clipping. 2.5% of patients developed postoperative neuropathic pain requiring medical treatment under which they fully improved. Over 80% of patients developed dermatomal hypoesthesia, with no reported effect on quality of life.

CONCLUSION

The surgical strategy of noneloquent nerve root clipping shows favorable outcomes and return-to-work rates. There are instances of neuropathic pain and dermatomal hypoesthesia with no significant morbidity. Despite the favorable outcome and low recurrence rate, nerve root-sparing surgical techniques should be further explored.

Evaluation of white matter integrity by using diffusion tensor imaging in spontaneous intracranial hypotension

OBJECTIVE

The aim is to investigate whether there is a microstructural change in the white matter pathways in patients with spontaneous intracranial hypotension (SIH). Additionally, the relationship between conventional magnetic resonance imaging (MRI) findings and diffusion tensor imaging (DTI) parameters is determined.

METHODS

Thirty patients diagnosed with SIH and 31 control patients (between January 2019 and February 2024) were included in the case-control study. MRI findings constituting the Bern score were evaluated in contrast-enhanced brain MRI. Ten different white matter pathways were evaluated with the following DTI parameters: fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusion (AD), and radial diffusion (RD). We also examined the association between MRI findings and DTI parameters.

RESULTS

In the cingulum, a decreased FA value (Z = -3.18, p = 0.002) was observed in patients with SIH, indicating disruption of white matter integrity and weakened synaptic transmission in this region. In the corona radiata, significant reductions were observed in both FA (Z = -5.67, p < 0.001) and AD (Z = -3.59, p < 0.001), alongside an increase in RD (Z = -4.99, p < 0.001). The concomitant increase in RD further supports the idea of potential damage to the myelin sheath, which, together with other findings, may reflect disruptions in white matter architecture that underlie the cognitive and motor deficits frequently seen in patients with SIH. In the splenium of the corpus callosum, a significant reduction in AD (Z = -3.00, p = 0.007) was also noted. In the anterior limb of the internal capsule (ALIC), both FA (Z = -4.57, p < 0.001) and AD (Z = -2.73, p = 0.012) values decreased, while RD increased (Z = -2.93, p = 0.007). These alterations suggest the involvement of motor and sensory pathways. In the posterior limb of the internal capsule (PLIC), significant reductions were found in both FA (Z = -5.59, p < 0.001) and AD (Z = -3.82, p < 0.001), along with an increase in RD (Z = -5.49, p < 0.001). In the corticospinal tract, patients with SIH exhibited a decrease in FA (Z = -4.15, p < 0.001), an increase in ADC (Z = -2.87, p = 0.008), and an increase in RD (Z = -3.73, p < 0.001). These findings represent significant microstructural changes reflecting a reduction in the integrity of motor pathways in white matter. In the middle cerebellar peduncle (MCP), patients with SIH showed increased ADC (Z = -4.78, p < 0.001) and RD (Z = -3.23, p = 0.002). Similarly, in optic radiation, there was decreased FA (Z = -4.55, p < 0.001) and AD (Z = -2.59, p = 0.018), with increased RD (Z = -2.95, p = 0.007). In the correlation analysis, positive correlations were found between suprasellar distance and AD values in both the ALIC (rs = 0.451, p = 0.012) and MCP (rs = 0.416, p = 0.022). These findings suggest that structural changes and anatomical shifts, especially in the suprasellar region, may be associated with microstructural changes in the adjacent white matter pathways.

CONCLUSION

We revealed microstructural changes in white matter in SIH. The alterations in DTI parameters may suggest that the white matter microarchitecture is changed as a result of mechanical compression of the axons in the white matter pathways due to brain prolapse and venous congestion.

Intracranial pressure monitoring in patients with spontaneous onset of orthostatic headache

BACKGROUND

Spontaneous intracranial hypotension (SIH) is a debilitating disorder, with an estimated annual incidence of 3.7 per 100,000. Diagnosing SIH can be challenging for clinicians, as patients frequently present with normal investigation findings. Intracranial pressure (ICP) monitoring has been proposed as a valuable tool for patients with orthostatic headaches that are highly suggestive of SIH but have inconclusive investigation results. The primary objective of this study was to determine the proportion of patients with spontaneous orthostatic headaches and normal diagnostic work-up who exhibited abnormal ICP monitoring results.

METHODS

This single-centre, retrospective observational study was conducted at a tertiary referral centre specialising in SIH and CSF dynamics disorders. Consecutive patients with spontaneous orthostatic headaches and inconclusive diagnostic work-up who underwent 24-hour ICP monitoring were considered eligible. The 24-hour ICP monitoring followed a standardised protocol, measuring median ICP and pulse amplitude (a marker of brain compliance) during the daytime, nighttime, and over the entire 24-hour period. Specific cut-offs for low and high ICP states were predetermined based on the best available current evidence.

RESULTS

Thirty-eight patients (23 females, mean age 41 years ± 14SD) were identified. All patients had orthostatic headaches with a spontaneous onset. The mean duration of symptoms was 46 months ± 36SD. ICP monitoring identified 3 patients (7.9%) with low ICP (mean of the median 24-hour ICP - 2 mmHg ± 2SD) and 6 patients (15.8%) with high ICP (mean of the median 24-hour ICP 9 mmHg ± 3SD). Obvious CSF dynamics disturbances were excluded in the remaining 29 patients (76.3%, mean of the median 24-hour ICP 3 mmHg ± 3SD). The only clinical feature that was more common in patients with abnormal ICP compared to patients with normal ICP results was audiovestibular disturbance, namely aural fullness or muffled hearing (67% versus 17%, p = 0.015). There were no complications from the ICP monitoring procedure for any patient.

CONCLUSIONS

When appropriately selected, patients with a clinical picture highly suggestive of SIH, who have a negative diagnostic work-up, may benefit from consideration of invasive ICP monitoring. Moreover, a significant minority of patients with orthostatic headache may paradoxically have a high CSF pressure state, which can be detected using ICP monitoring.

MEETING PRESENTATIONS

Portions of this work were presented in abstract and oral presentation form at the Twenty-eighth Anglo-Dutch Migraine Association meeting (08/06/2018), the Tenth Meeting of the International Society for Hydrocephalus and Cerebrospinal Fluid Disorders (20/10/2018; Bologna, Italy), the Society of British Neurological Surgeons 2018 Autumn Meeting (19/09/2018; London, United Kingdom), and the European Association of Neurosurgical Societies 2023 congress (27/09/2023; Barcelona, Spain). This work is also part of the doctoral thesis of one of the authors (LD).

MRI and Surgical Findings Refine Concepts of Type 2 Cerebrospinal Fluid Leaks in Spontaneous Intracranial Hypotension

Background Type 2 lateral spinal cerebrospinal fluid (CSF) leakage occurs in approximately 20% of cases of spontaneous intracranial hypotension (SIH); however, the underlying pathologic mechanism remains ambiguous. Purpose To characterize MRI features of type 2 leaks, correlate them with intraoperative observations, and evaluate their diagnostic value. Materials and Methods Patients with SIH and type 2 leaks diagnosed between January 2021 and February 2023 were retrospectively identified. Characteristic imaging features from heavily T2-weighted MR myelography (T2-MRM) images were reevaluated (independently and blinded) in the type 2 leak sample mixed with a sample of 40 patients with SIH and type 1 (ventral) leaks. Available intraoperative data were reviewed for lateral dural tears, arachnoid outpouching, and ruptured spinal meningeal diverticula. Results Twenty-eight patients with SIH (mean age, 37.3 years ± 8.2 [SD]; 22 [79%] female patients) had 29 type 2 leaks between the T7 and L2 levels without side predominance. Characteristic cystic lesions with a broad dural base on the exiting nerve root sleeve were identified at T2-MRM; this "bud-on-branch" sign reflects an arachnoid outpouching herniating through a lateral dural tear, distinct from a meningeal diverticulum, which yielded a sensitivity of 79% (22 of 28; 95% CI: 59, 92) and a specificity of 100% (40 of 40; 95% CI: 91, 100) for leak location. Arachnoid outpouching was confirmed intraoperatively in 23 of 25 patients (92%; 95% CI: 81, 100), originating from the nerve root sleeve axilla in most patients (19 of 25, 76%; 95% CI: 59, 93); two of 25 patients (8%; 95% CI: 0, 19) had a dural tear only, and none had an underlying ruptured meningeal diverticulum. Conclusion This study showed that type 2 leaks are actually due to a lateral dural nerve root sleeve tear through which the arachnoid herniates, which contrasted the common perception that these leaks result from ruptured meningeal diverticula. These leaks had a characteristic anatomic distribution and MRI appearance with substantially facilitated leak localization in patients with SIH. © RSNA, 2025 Supplemental material is available for this article. See also the editorial by Rovira and Torres-Ferrús in this issue.

Role of CT myelography in the diagnosis and management of spontaneous intracranial hypotension

INTRODUCTION

Spontaneous intracranial hypotension (SIH) is a secondary cause of headache. Its pathophysiology is complex, and relies mainly on the notion of a localized leak, and thus a loss of cerebrospinal fluid (CSF) in the spinal region. SIH is little known to the medical profession, for which CT myelography is a technique on the rise, allowing to identify and treat the leak using a blood-patch or a fibrin sealant. The aim of the study was to investigate the contribution of CT myelography in the diagnostic and therapeutic management of spontaneous intracranial hypotension, its modalities and population characteristics.

MATERIAL AND METHODS

A cohort of patients with spontaneous intracranial hypotension who underwent a CT myelography in our department was retrospectively studied. Nineteen patients were included between March 2020 and October 2022.

RESULTS

CT myelography allowed identification of an etiology in 16 patients (84 %). The etiology of the leak was mainly a dural tear, identified in 11 patients. One diverticulum and 4 CSF-venous fistulas were identified. First targeted injection of fibrin sealant allowed stopped the leak in 12 out of 17 patients.

CONCLUSION

CT myelography allows to identify the etiology of the CSF leak and pinpoint its topography. CT guidance can then be used to treat the leak in the same therapeutic timeframe, with greater efficacy during the first targeted injection of fibrin sealant. The current study data showed a high incidence of dural tears, and a significant proportion of venous-dural fistulas, and a low incidence of diverticulum.

Spontaneous intracranial hypotension - a spinal disease

Spontaneous intracranial hypotension (SIH) remains an underdiagnosed condition despite increasing awareness due to recent scientific advances. Diagnosis can be delayed by the broad clinical presentation and imaging pitfalls. This results in a high degree of physical impairment for patients, including social and psychological sequelae as well as long-term damage in the case of delayed diagnosis and treatment.The study is based on a selective literature search on PubMed including articles from 1990 to 2023 and the authors' clinical experience from working in a CSF center.SIH mostly affects middle-aged women, with the primary symptom being position-dependent orthostatic headache. In addition, there is a broad spectrum of possible symptoms that can overlap with other clinical conditions and therefore complicate the diagnosis. The causative spinal CSF loss can be divided into three main types: ventral (type 1) or lateral (type 2) dural leak and CSF-venous fistula (type 3). The diagnosis can be made using a two-stage workup. As a first step, noninvasive MRI of the head and spine provides indicators of the presence of SIH. The second step using focused myelography can identify the exact location of the cerebrospinal fluid leak and enable targeted therapy (surgical or interventional). Intrathecal pressure measurement or intrathecal injection of gadolinium is no longer necessary for primary diagnosis. Serious complications in the course of the disease can include space-occupying subdural hematomas, superficial siderosis, and symptoms of brain sagging, which can lead to misinterpretations. Treatment consists of closing the dural leak or the cerebrospinal fluid fistula. Despite successful treatment, a relapse can occur, which highlights the importance of follow-up MRI examinations and emphasizes the chronic nature of the disease. This paper provides an overview of the diagnostic workup of patients with suspected SIH and new developments in imaging and therapy. · SIH is an underdiagnosed condition with a wide range of possible symptoms.. · The first diagnostic step using MRI provides indications of the presence of SIH.. · The second diagnostic step using (dynamic) myelography can identify the CSF leak.. · Collaboration with a CSF center is advisable for further diagnosis and treatment.. · Prompt detection and treatment of SIH improves the outcome.. · Zander C, Wolf K, El Rahal A et al. Spontaneous intracranial hypotension - a spinal disease. Fortschr Röntgenstr 2024; DOI 10.1055/a-2318-8994.

Diagnosis and treatment of disorders of intracranial pressure: consensus statement of the Spanish Society of Neurology's Headache Study Group

Primary intracranial pressure disorders include idiopathic intracranial hypertension and spontaneous intracranial hypotension. Remarkable advances have been made in the diagnosis and treatment of these 2entities in recent years. Therefore, the Spanish Society of Neurology's Headache Study Group (GECSEN) deemed it necessary to prepare this consensus statement, including diagnostic and therapeutic algorithms to facilitate and improve the management of these disorders in clinical practice. This document was created by a committee of experts belonging to GECSEN, and is based on a systematic review of the literature, incorporating the experience of the participants, and establishes practical recommendations with levels of evidence and grades of recommendation.

Magnetic Resonance Imaging Diagnosis of Spinal Longitudinal Epidural Collections in a Spontaneous Spinal Dural Breach and Successful Surgical Treatment

Spontaneous intracranial hypotension is generally secondary to cerebrospinal fluid leaks. Spinal magnetic resonance imaging is an important part of the diagnostic workup, especially to display spinal longitudinal epidural collections. Other causes of leaks include nerve root sleeve tear and cerebrospinal fluid-venous fistula. We propose a standard magnetic resonance imaging protocol including sagittal T1, T2-weighted, and T2 fat-saturated sequences, with addition of high-resolution three-dimensional T2 images to improve detection of spinal longitudinal epidural collections and help locate the dural breach level. Spine computed tomography may prove useful in detecting a bony spur that may cause the dural breach. Treatment of identified dural breaches includes targeted epidural blood patch or neurosurgery in case of blood patch inefficacy. Few cases of successful surgical treatments of dural breaches have been reported with complete regression of spinal longitudinal epidural collections; thus more studies will be valuable to help establish guidelines in this pathology.

Dorsolateral Transdural Surgical Management of Spontaneous Intracranial Hypotension From Ventral Dural Cerebrospinal Fluid Leaks: Case Series and Technical Report

BACKGROUND AND OBJECTIVES

Spontaneous intracranial hypotension is an uncommon but debilitating condition that commonly involves positional headaches and vertigo. One cause is cerebrospinal fluid (CSF) leakage from ventral dural defects from calcified spinal discs. Patients can undergo epidural blood or fibrin glue patches as treatment; however, in cases where the leak does not resolve, surgical repair of the dural tear may be warranted. We aim to describe a case series and technical notes for these patients.

METHODS

Patients with spontaneous intracranial hypotension because of myelography-confirmed ventral dural defect from calcified thoracic disc, who were treated surgically between June 2020 and March 2024, were included in the study cohort. Demographic information, clinical course, and postoperative outcomes were collected. The surgical technique was also described based on an illustrative case.

RESULTS

Twelve consecutive patients underwent surgery between June 2020 and March 2024 with postoperative records. The median age at the time of surgery was 41.5 years (range: 28-58 years). Male patients comprised 50% of the cohort. Dural defects were spread throughout the thoracic spine in the cohort. While all patients reported positional headaches, other symptoms included vertigo, pulsatile tinnitus, and neck pain. Median length of follow-up time was 6.5 weeks. There were no surgical complications or permanent neurologic deficits. All patients had radiologic cure of their leaks with absence of extradural CSF on postoperative MR imaging. Ten patients (83.3%) had complete resolution of spontaneous intracranial hypotension-related symptoms. Two patients did suffer from rebound headaches postoperatively.

CONCLUSION

The dorsolateral transdural surgical approach is a safe and effective method to repair type 1 CSF leaks caused by ventral dural defects. Our case series of 12 patients did not involve any surgical or immediate postoperative complications, and all patients had radiologic resolution of their leaks with relief of positional headaches. Two patients experienced continued headaches after treatment.

Different Glymphatic Kinetics in Spontaneous Intracranial Hypotension

BACKGROUND AND PURPOSE

The glymphatic (glia-lymphatic) system is a paravascular pathway for the clearance of waste metabolites including amyloid β from the brain. Serial T1 relaxation time measurements after the intrathecal injection of gadolinium-based contrast agents facilitate the analysis of the temporal dynamics that may be different in patients with spontaneous intracranial hypotension (SIH) and those without SIH.

MATERIALS AND METHODS

3D T1-weighted magnetization-prepared 2 rapid gradient echo sequences were acquired in 4 patients with SIH with proved CSF leaks and 12 patients without SIH before, 2-4, 6-8, and 24-48 hours after intrathecal gadobutrol injection. MR scans were warped to the Montreal Neurological Institute space and serial scans were coregistered. T1 relaxation times were measured in predefined ROIs including the subarachnoid space, cortex, white matter, and cervical lymph nodes.

RESULTS

In the subarachnoid space and cortex, T1 relaxation times decreased after 2-4 and 6-8 hours before they increased again. In contrast, in the white matter of the temporal lobe T1 relaxation time still decreased after 24-48 hours. There was a striking difference in patients with SIH who did not show a clear contrast distribution within the brain parenchyma.

CONCLUSIONS

T1 relaxation time curves are compatible with a convective flow driven by arterial pulsations via paravascular spaces surrounding penetrating arteries into the brain's interstitial fluid in the deep white matter. Different curves in patients with SIH and those without SIH indicate that the CSF pressure also impacts the temporal kinetics of the glymphatic system.

Spinal dementia: Don't miss it, it's treatable

BACKGROUND & PURPOSE

Around 5% of dementia patients have a treatable cause. To estimate the prevalence of two rare diseases, in which the treatable cause is at the spinal level.

METHODS

A radiology information system was searched using the terms CT myelography and the operation and classification system (OPS) code 3-241. The clinical charts of these patients were reviewed to identify patients with a significant cognitive decline.

RESULTS

Among 205 patients with spontaneous intracranial hypotension (SIH) and proven CSF leaks we identified five patients with a so-called frontotemporal brain sagging syndrome: Four of those had CSF venous fistulas and significantly improved by occluding them either by surgery or transvenous embolization. Another 11 patients had infratentorial hemosiderosis and hearing problems and ataxia as guiding symptoms. Some cognitive decline was present in at least two of them. Ten patients had ventral dural tears in the thoracic spine and one patient a lateral dural tear at C2/3 respectively. Eight patients showed some improvement after surgery.

DISCUSSION

It is mandatory to study the (thoracic) spine in cognitively impaired patients with brain sagging and/ or infratentorial hemosiderosis on MRI. We propose the term spinal dementia to draw attention to this region, which in turn is evaluated with dynamic digital subtraction and CT myelography.

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.

Cerebrospinal Fluid Leak Secondary to Whiplash Injury

Although rare, cerebrospinal fluid (CSF) leaks can prove to be detrimental if severe. Usually secondary to dural punctures, CSF leaks can present as severe headaches, neck pain, blurry vision, confusion, and nausea. However, patients can also be asymptomatic. Due to the rarity and variability in symptom presentation, the diagnosis of these leaks is often missed. We present a case of a 15-year-old female who had been experiencing severe headaches after she hyperextended her neck during a horseback ride. On diagnostic imaging, a CT myelogram confirmed a CSF leak with contrast extravasation along the left T9 nerve root up to the T3-T4 levels. After confirmation, the patient received an epidural blood patch, with 15 ml of autologous blood injected into the epidural space. After the procedure, the patient experienced significant symptomatic relief, resulting in an 80% improvement in her pain scale. Our case demonstrates how a prompt and accurate diagnosis of a CSF leak can optimize patient outcomes.

Lateral Spinal CSF Leaks in Patients with Spontaneous Intracranial Hypotension: Radiologic-Anatomic Study of Different Variants

BACKGROUND AND PURPOSE

Spinal CSF leaks cause spontaneous intracranial hypotension. Several types of leaks have been identified, and one of these types is the lateral dural tear. Performing myelography with the patient in the decubitus position allows precise characterization of these leaks. The purpose of the current study was to describe the different variants of spontaneous lateral CSF leaks.

MATERIALS AND METHODS

This retrospective cohort study included a consecutive group of patients with spontaneous intracranial hypotension and lateral CSF leaks who underwent digital subtraction myelography in the decubitus position and underwent surgery to repair the CSF leak between July 2018 and June 2023.

RESULTS

The mean age of the 53 patients (37 women and 16 men) was 35.5 years. Three different variants of lateral CSF leak could be identified. Forty-nine patients (92.5%) had a lateral dural tear associated with the nerve root sleeve. The dural tear was at the axilla of the nerve root sleeve in 36 patients (67.9%) and at the shoulder in 13 patients (24.5%). Four patients (7.5%) had a lateral dural tear at the level of the pedicle that was not associated with the nerve root sleeve. Findings on digital subtraction myelography were concordant with intraoperative findings in all patients. An extradural CSF collection was seen in all patients with a lateral dural tear associated with the nerve root sleeve but in only 2 of the 4 patients with the pedicular variant of a lateral dural tear.

CONCLUSIONS

We identified 3 variants of spontaneous lateral dural tears. Most lateral dural tears are associated with extradural CSF collections and arise from either the axilla (67.9%) or the shoulder (24.5%) of the nerve root sleeve. Lateral dural tears at the level of the pedicle (7.5%) not associated with the nerve root sleeve are uncommon and may require specialized imaging for their detection.

Non-invasive biomarkers for spontaneous intracranial hypotension (SIH) through phase-contrast MRI

BACKGROUND AND OBJECTIVE

Spontaneous intracranial hypotension (SIH) is an underdiagnosed disease. To depict the accurate diagnosis can be demanding; especially the detection of CSF-venous fistulas poses many challenges. Potential dynamic biomarkers have been identified through non-invasive phase-contrast MRI in a limited subset of SIH patients with evidence of spinal longitudinal extradural collection. This study aimed to explore these biomarkers related to spinal cord motion and CSF velocities in a broader SIH cohort.

METHODS

A retrospective, monocentric pooled-data analysis was conducted of patients suspected to suffer from SIH who underwent phase-contrast MRI for spinal cord and CSF velocity measurements at segment C2/C3 referred to a tertiary center between February 2022 and June 2023. Velocity ranges (mm/s), total displacement (mm), and further derivatives were assessed and compared to data from the database of 70 healthy controls.

RESULTS

In 117 patients, a leak was located (54% ventral leak, 20% lateral leak, 20% CSF-venous fistulas, 6% sacral leaks). SIH patients showed larger spinal cord and CSF velocities than healthy controls: e.g., velocity range 7.6 ± 3 mm/s vs. 5.6 ± 1.4 mm/s, 56 ± 21 mm/s vs. 42 ± 10 mm/s, p < 0.001, respectively. Patients with lateral leaks and CSF-venous fistulas exhibited an exceptionally heightened level of spinal cord motion (e.g., velocity range 8.4 ± 3.3 mm/s; 8.2 ± 3.1 mm/s vs. 5.6 ± 1.4 mm/s, p < 0.001, respectively).

CONCLUSION

Phase-contrast MRI might become a valuable tool for SIH diagnosis, especially in patients with CSF-venous fistulas without evidence of spinal extradural fluid collection.

Keyhole Fenestration for Cerebrospinal Fluid Leaks in the Thoracic Spine: Quantification of Bone Removal and Microsurgical Anatomy

BACKGROUND AND OBJECTIVE

A safe working trajectory is mandatory for spinal pathologies, especially in the midline, anterior to the spinal cord. For thoracic cerebrospinal fluid (CSF) leaks, we developed a minimally invasive keyhole fenestration. This study investigates the necessary bone removal for sufficient exposure of different leak types particularly regarding weight-bearing structures.

METHODS

In this retrospective case series between January 2022 and June 2023, the volume of bone resection and the axial and sagittal diameter of hemilamina defects after closure through keyhole fenestration were quantified. The involvement of facet joints and pedicles was qualitatively rated. Demographic (age, sex, body mass index, leak type) and surgical data (blood loss, surgery time, discharge after surgery) and complications were analyzed.

RESULTS

Thirty-three patients with 34 approaches were included. The volume of resected bone was 1.5 cm3, and the diameter of the hemilamina defect was 17.8 mm in the sagittal and 15.1 mm in the axial plane. Facet joints were uninvolved in 24% and partly resected in 74%, and one facet joint was resected completely. Pedicles remained intact in 71% and were minimally involved in 29%. The median surgery time was 93 minutes, blood loss was 45 mL, and discharge was 4 days after surgery. Three patients (9%) needed revision surgery. No relevant and persisting morbidity occurred. Within the median follow-up period of 10 months, no stabilizing surgery was necessary. No permanent neurological deficit occurred.

CONCLUSION

The keyhole fenestration leaves weight-bearing structures like facet joints and pedicles intact in most cases. The limited, penny-sized bone resection is sufficient to reach and close thoracic CSF leaks Type 1, 2, and 3 from the anterior midline to the ganglion. For experienced centers, it is a universal minimally invasive approach for treating all CSF leaks.

A Low-Volume Epidural Blood Patch for the Treatment of Spontaneous Intracranial Hypotension: A Case Report

Spontaneous intracranial hypotension (SIH) is a rare neurological syndrome. We report the case of a 47-year-old woman with acute, severe orthostatic headache after surgery, chemotherapy, and radiotherapy for breast cancer. The brain and spine magnetic resonance imaging showed signs of intracranial hypotension. We describe the results of a non-targeted epidural blood patch with 10 mL of the patient's blood administered after unsuccessful conservative treatment. After the procedure, the patient reported gradual headache relief. This effect persisted over one year. The case shows that a single non-targeted low-volume epidural blood patch can be an effective treatment option for a patient with SIH when conservative treatment fails.

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.

Don't delay, but don't despair: symptom duration, comorbidity and outcome after closure of spinal cerebrospinal fluid leaks

OBJECTIVE

Microsurgical sealing of spinal cerebrospinal fluid (CSF) leaks is a viable treatment option in spontaneous intracranial hypotension (SIH). Several factors may influence the outcome, with symptom duration probably the most modifiable variable.

METHODS

Patients with closure of spinal CSF leaks between September 2020 and March 2023 and a follow-up period of 6 months were included in this retrospective single-center study. Pre- and postoperative scores for impact of headaches (Headache Impact Test, HIT-6) and quality of life (QoL, EQ-5D-5L) were systematically collected. Multiple regression modelling and subgroup analyses for different symptom durations and comorbidities were performed for these outcomes.

RESULTS

One hundred patients (61% female, median age 43.5 years) were included. Six months postoperatively, there was significant improvement in headache impact (HIT-6: 66 (IQR 62-69) to 52 (IQR 40-61, p < 0.001) and QoL (EQ-5D-5L VAS: 40 (IQR 30-60) to 79 (IQR 60-90); EQ-5D-5L Index: 0.67 (IQR 0.35-0.8) to 0.91 (IQR 0.8-0.94, p < 0.001, respectively). Subgroup analysis for a symptom duration above (74%) and below 90 days (26%) and comorbidity, as well as multiple regression analysis, revealed a trend in favor of early treatment and lower comorbidity. However, even after a prolonged symptom duration, improvements were significant.

CONCLUSION

As patients with shorter symptom duration show a trend for a better outcome, our results promote a timely diagnosis and treatment in SIH patients. However, a significant postoperative improvement can still be expected even after a prolonged symptom duration.

Spontaneous Intracranial Hypotension: Case Report and Update on Diagnosis and Treatment

Spontaneous intracranial hypotension (SIH) is an important cause of daily headaches that occur in young and middle-aged, active persons and is often misdiagnosed, leading to prolonged inactivity and rather high healthcare expenditures. Its diagnosis requires a high degree of clinical suspicion and careful interpretation of imaging studies. We present a case of SIH, which was successfully treated but which posed serious diagnostic challenges, ranging from cerebro-vascular disease and meningitis to granulomatous diseases, and for whom every therapeutic attempt just worsened the patient's condition until we finally reached the correct diagnosis. To raise awareness of this condition, we also present an updated overview of the clinical picture, evaluation, and treatment options for SIH.

Real-life study of the use of oto-acoustic emissions in the diagnosis of intracranial hypotension

BACKGROUND

The diagnosis of spontaneous or post-traumatic intracranial hypotension (IH) mainly relies on clinical features and neuro-imaging. However, the results of brain and spine magnetic resonance imaging are not always contributive. There is an interest for other non-invasive procedures, able to confirm or refute the diagnosis. The use of oto-acoustic emissions (OAE) was previously reported on isolated cases of IH associated with endolymphatic hydrops (ELH). The aim of this study was to assess the real-life utilization of this electrophysiological method in a larger population of suspected IH.

METHODS

A retro-prospective cohort study was conducted from November 2013 to July 2022 in patients with a suspected or doubtful diagnosis of IH. They were assessed for ELH by recording bilateral distortion product of oto-acoustic emissions (DPOAE) in sitting then in supine position.

RESULTS

Among the 32 patients assessed, the diagnostic of IH was confirmed in 18 patients. An ELH was shown in 15 of them (83%), but also in seven other patients. They had several differential diagnoses: chronic migraine, Chiari malformation, rebound intracranial hypertension and perilymph fistula.

CONCLUSIONS

This procedure seems to be insufficient to exclude differential diagnosis when intracranial hypotension is suspected.

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.

Headache Disorders: Differentiating Primary and Secondary Etiologies

In the initial assessment of a headache patient, several dangerous secondary etiologies must be considered. A thorough history and physical examination, along with a comprehensive differential diagnosis may alert a physician to the diagnosis of a secondary headache particularly when it is accompanied by certain clinical features. Evaluation and workup include a complete neurological examination, consideration of neuroimaging, and serum/spinal fluid analysis if indicated. Careful attention to the patients' history and physical examination will guide the diagnostic work-up and management. In this review, we summarize the diagnostic workup of various primary and secondary headache etiologies. Although most headaches are primary in nature, it is essential to screen for headache "red flags", as they can suggest life threatening secondary etiologies. When secondary causes are suspected, appropriate neuroimaging can further differentiate the underlying cause. The appropriate imaging is dependent on the most likely secondary etiology, which is deduced from history and physical examination. When no red flags are present, primary headaches are more likely. These can be differentiated by frequency, location, duration, triggers, and presence of aura. The different clinical presentations for secondary headaches, as well as the distinguishing features for primary headaches are outlined in this review.

Spontaneous Intracranial Hypotension and Subdural Hematomas Treatment Management Using MMA Embolization and Target Blood Patch: A Case Report

We report a patient suffering from spontaneous intracranial hypotension (SIH) who, following a non-selective lumbar blood patch, returned to his healthcare provider with severe symptoms of neurological deficits. It was subsequently discovered that the aforementioned deficits were due to a bilateral subdural hematoma, and an emergency surgical drainage of the hematoma has been performed. However, the hematoma reformed and potential cerebrospinal fluid leakage was consequently investigated through myelography. Following the diagnostic finding of a venous diverticulum, a selective blood patch was executed in the affected area, and in order to stabilize the hematoma, an embolization of the middle meningeal arteries was performed. The combination of such operations allowed for the resorption of the hematoma and the improvement of neurological symptoms.

CT-guided percutaneous cyanoacrylate injection targeting the spinal cerebrospinal fluid leak: a potential therapeutic option for spontaneous intracranial hypotension

BACKGROUND

We report the first case series of spontaneous intracranial hypotension (SIH) patients who underwent CT-guided percutaneous cyanoacrylate injection targeting the cerebrospinal fluid (CSF) leak.

METHODS

A retrospective analysis was performed for all consecutive cases of SIH patients with CSF leak confirmed on CT myelography, treated by CT-guided percutaneous cyanoacrylate injection at our institution from 2016 to 2022. On pretreatment brain and spine MRIs, we analyzed signs of SIH according to the Bern score, and dichotomized cases into positive/negative for spinal longitudinal extradural CSF collection (SLEC-P or SLEC-N). The leaks detected on CT myelography were classified into three types according to Schievink et al. We collected the Headache Impact Test 6 (HIT-6) scores throughout a 6-month follow-up, with a brain CT scan at each visit.

RESULTS

11 patients were included (mean age 48.4 years, six men). Five SLEC-P type 1, three SLEC-P type 2, and three SLEC-N type 3 leaks were identified. All patients had significant signs of SIH on pretreatment brain MRI (mean Bern score 7.8±1.1). Six patients underwent a foraminal puncture, and five patients had a cervical epidural approach. Two patients experienced mild and transient locoregional pain after cervical epidural injection. Mean HIT-6 score at baseline was 66.8±3.2 and at the 6-month follow-up was 38±3.6 (P<0.001). All patients achieved improvement in their symptoms, with 82% of them (9/11) having complete resolution of headaches and SIH findings on CT scans at 6 months. No clinical worsening or recurrence was observed.

CONCLUSIONS

CT-guided percutaneous cyanoacrylate injection may be a potential therapeutic option for the different types of CSF leak causing SIH.

The cervical blood patch: A therapeutic "miraculous" for cerebrospinal fluid leaks: A case report

RATIONALE

Cerebrospinal fluid (CSF) leaks, arising from abnormal openings in the protective layers surrounding the spinal cord and brain, are a significant medical concern. These leaks, triggered by various factors including trauma, medical interventions, or spontaneous rupture, lead to the draining of CSF-an essential fluid safeguarding the nervous system. A classic symptom of CSF leaks is an incapacitating headache exacerbated by sitting or standing but relieved by lying down. Spontaneous intracranial hypotension (SIH) denotes the clinical condition marked by postural headaches due to spontaneous CSF leakage and hypotension, often misdiagnosed or underdiagnosed. While orthostatic headaches are the hallmark, SIH may manifest with an array of symptoms including nausea, tinnitus, hearing loss, visual disturbances, and dizziness. Treatment options encompass conservative measures, epidural blood patches (EBP), and surgery, with EBP being the primary intervention.

PATIENT CONCERN

The patient did not express any specific concerns regarding their medical diagnosis. However, they did harbor apprehensions that their condition might necessitate surgical intervention in the future.

DIAGNOSIS

The patient had been treated with antibiotics with a pre-diagnosis of sinusitis and was admitted to the neurology department of our hospital when his symptoms failed to improve. Cranial magnetic resonance imaging was interpreted as thickening of the dural surfaces and increased contrast uptake, thought to be due to intracranial hypotension. Cranial MR angiography was normal. Full-spine magnetic resonance imaging revealed a micro-spur at the C2 to 3 level and the T1 to 2 level in the posterior part of the corpus.

INTERVENTIONS

The cervical EBP was performed in the prone position under fluoroscopic guidance. There were no complications.

OUTCOMES

The patient was invited for follow-up 1 week after the procedure, and control examination was normal.

LESSONS

SIH poses a diagnostic challenge due to its diverse clinical presentation and necessitates precise imaging for effective intervention. Cervical EBP emerges as a promising treatment modality, offering relief and improved quality of life for individuals grappling with this condition. However, clinicians must carefully assess patients and discuss potential risks and benefits before opting for cervical blood patches.

Acquired tonsillar herniation related to spontaneous intracranial hypotension: case reports

Background

Acquired prolapse of the cerebellar tonsils in spontaneous intracranial hypotension (SIH) patients is rare. This study aims to evaluate neuroimaging changes of acquired prolapse of the cerebellar tonsils below the foramen magnum in SIH patients due to spontaneous spinal cerebrospinal fluid leakage, which was treated by targeted epidural blood patches (EBP).

Methods

We retrospectively reviewed clinical and neuroimaging characteristics of 5 cases of SIH with acquired prolapse of the cerebellar tonsils that received targeted EBP in our institution from January 2013 to December 2016.

Results

Of these SIH patients, all of them suffered from an orthostatic headache. Initial cranial MRI demonstrated descent of the cerebellar tonsils ≥5 mm. Intrathecal gadolinium-enhanced spinal MR myelography and/or spinal MR hydrography were performed to evaluate the level of spinal cerebrospinal fluid leakage. Symptoms were alleviated in all 5 patients after two (n = 4), or three (n = 1) targeted EBP during hospitalization. Follow-up cranial MRI revealed that the descent of cerebellar tonsils was reversed after EBP treatment.

Conclusion

Acquired tonsillar herniation can occur in patients with SIH and spinal cerebrospinal fluid leakage. Symptoms of these patients may be resolved and radiologic findings may be reversed after EBP treatment.

Spontaneous Intracranial Hypotension: A Review of Neuroimaging and Current Concepts

Spontaneous intracranial hypotension (SICH) is the emerging cause of orthostatic headache as it has been better recognized in recent years. SICH happens due to spinal cerebrospinal fluid (CSF) leak; however, the manifestations are predominantly cranial and hence imaging in SICH includes brain and spine. There are few characteristic brain imaging features to be concerned about to diagnose SICH in patients with vague symptoms or low clinical suspicion. Spine screening is recommended in these patients to assess spinal CSF leaks. While neuroradiologists play a significant role from the time of diagnosis to treatment of SICH, there is a need for all the general radiologists to be aware of the condition. Computed tomography myelogram and digital subtraction myelogram are performed for diagnostic and therapeutic management of SICH. There is a known risk for SICH recurrence in patients with sagittal longitudinal epidural collection and hence, targeted blood patch should be used instead of blind patch. Most importantly, slow mobilization is recommended following the patch to avoid recurrence.

[Spinal Presentation of Spontaneous Intracranial Hypotension]

Spontaneous intracranial hypotension (SIH), which generally presents as orthostatic headache, is increasingly being identified due to improved imaging technologies and heightened awareness. Many prior studies have reported the characteristic brain MRI findings of SIH. However, recently, focus has shifted to spinal MRI, as SIH is believed to be caused by leakage of cerebrospinal fluid from the spinal dural sac. Advanced techniques such as ultrafast CT myelography and digital subtraction myelography have emerged as useful technique to identify the site of cerebrospinal fluid leakage. In this review, we discuss the diagnosis, spinal MRI findings, imaging techniques, and treatment of SIH.

Management of Tarlov cysts: an uncommon but potentially serious spinal column disease-review of the literature and experience with over 1000 referrals

Tarlov cysts were thought to be anatomic variants of uncertain etiology and clinical significance when initially described over 80 years ago. They are often detected in routine lumbosacral imaging and generally not reported in a differential diagnosis. There is increasing evidence that at least some Tarlov cysts are symptomatic and can have a significant adverse impact on patients' health and well-being. Women are disproportionately affected with this condition, often presenting with long-standing pain and neurological dysfunctions. Significant gender bias has been a concern in the management of these patients. Unfortunately, there is no consensus on patient selection or management approaches for symptomatic Tarlov cysts. This review article updates information on the prevalence, diagnosis, clinical significance, and treatments of these cysts. Based on these findings and experience with over 1000 patient referrals, a treatment decision algorithm for symptomatic Tarlov cysts was constructed to provide guidance for appropriate management of patients with these complex cysts.

Prevalence of SLEC-negative spontaneous intracranial hypotension in patients with spinal nerve root sleeve diverticula on MRI

PURPOSE

While there is thought to be an association between spinal nerve root diverticula (NRD) and spontaneous intracranial hypotension (SIH) without a spinal longitudinal epidural collection (SLEC), it remains unclear what the overall prevalence of SLEC-negative SIH is in patients with NRD on MRI.

METHODS

Spine MRI imaging reports from our single institution were electronically screened for instances of NRD over a 9-year period (2016-2023). From these cases, patients with brain MRIs consistent with SIH were also identified. Subsequently, the overall proportion of SLEC-negative SIH was determined as a function of total cases with NRD based on spinal level.

RESULTS

In total, 83,843 patients with spinal MRIs were screened which identified 4174 (4.97%) with NRD. From these, there were 1203 cervical, 622 thoracic, and 2979 lumbosacral spine MRIs. In total, 16 patients (0.38%; Standard Error [SE]: 0.48%-0.28%) had a brain MRI compatible with SLEC-negative SIH and met ICHD-3 criteria. Patients with cervical NRD had SIH in 2 cases (0.16%; SE: 0.27%-0.05%). SLEC-negative SIH was present in 11 patients with lumbosacral NRD (0.34%; SE: 0.44%-0.24%). In patients with diverticula in the thoracic spine, 14 (2.3%; SE: 2.8%-1.8%) had SLEC-negative SIH. SLEC-negative SIH was significantly more prevalent in patients with thoracic diverticula compared to those with cervical (p<.0001) or lumbosacral NRD (p<.0001).

CONCLUSION

In patients with spinal NRD, concurrent SLEC-negative SIH is present in approximately 0.38% of patients, suggesting that in the vast majority of cases, they are an incidental finding. However, SIH is present in approximately 2.3% of patients with thoracic NRD and may be more specific for leak localization.

Prone Dynamic CT Myelography in Spontaneous Intracranial Hypotension : Diagnostic Need and Radiation Doses

BACKGROUND AND PURPOSE

The diagnostic work-up in patients with spontaneous intracranial hypotension (SIH) and spinal longitudinal extradural CSF collection (SLEC) on magnetic resonance imaging (MRI) comprises dynamic digital subtraction myelography (dDSM) in prone position for leak detection. Dynamic computed tomography (CT) myelography (dCT-M) in prone position follows if the leak is not unequivocally located. A drawback of dCT‑M is a high radiation dose. This study evaluates the diagnostic needs of dCT-M examinations and measures to reduce radiation doses.

METHODS

Frequency, leak sites, length and number of spiral acquisitions, DLP and effective doses of dCT‑M were retrospectively recorded in patients with ventral dural tears.

RESULTS

Of 42 patients with ventral dural tears, 8 underwent 11 dCT‑M when the leak was not unequivocally shown on digital subtraction myelography. The median number of spiral acquisitions was 4 (range 3-7) and the mean effective radiation dose 30.6 mSv (range 13.1-62.16 mSv) mSv. Five of eight leaks were located in the upper thoracic spine (range C7/Th1-Th2/3). Bolus tracking of intrathecal contrast agent in dCT‑M was used to limit the number and length of spiral acquisitions.

DISCUSSION

A dCT‑M in prone position to localize a ventral dural tear is needed in every fifth patient with a SLEC on MRI. It is typically needed when the leak is located in the upper thoracic spine and when patients have broad shoulders. Measures to reduce the radiation dose include bolus tracking or to repeat the DSM with adjusted positioning of patient.

Recovery and long-term outcome after neurosurgical closure of spinal CSF leaks in patients with spontaneous intracranial hypotension

INTRODUCTION

Spontaneous intracranial hypotension due to a spinal cerebrospinal fluid leak causes orthostatic headaches and impacts quality of life. Successful closure rates are often reported, whereas data on long-term outcome are still scarce.

METHODS

Between April 2020 and December 2022 surgically treated patients completed the Headache Impact Test-6 prior to surgery and at 14 days, three months, six months, and 12 months postoperatively. In addition to the Headache Impact Test-6 score, we extracted data related to orthostatic symptoms.

RESULTS

Eighty patients were included. Median Headache Impact Test-6 score preoperatively was 65 (IQR 61-69), indicating severe and disabling impact of headaches. At three months headache impact significantly improved to 49 (IQR 44-58) (p < 0.001) and remained stable up to 12 months (48, IQR 40-56), indicating little to no impact of headaches on quality of life. The need to lie down "always" or "very often" was reduced from 79% to 23% three months postoperatively (p < 0.001).

CONCLUSIONS

Surgical closure of spinal CSF leaks significantly improves the impact of headaches in the long term. At least three months should be expected for recovery. Despite permanent closure of the CSF-leak, a quarter of patients still have relevant long-term impairment, indicating the need for further research on its cause and possible treatment.

Overview of Spontaneous Intracranial Hypotension and Differential Diagnosis with Chiari I Malformation

Spontaneous intracranial hypotension (SIH) occurs due to a leakage of the cerebrospinal fluid (CSF) lowering the pressure of subarachnoid space, mostly caused by a dural breach or discogenic microspur. As a result of less support provided by CSF pressure, intracranial structures are stretched downward, leading to a constellation of more or less typical MRI findings, including venous congestion, subdural effusions, brainstem sagging and low-lying cerebellar tonsils. Clinic examination and an MRI are usually enough to allow for the diagnosis; however, finding the location of the dural tear is challenging. SIH shares some MRI features with Chiari malformation type I (CM1), especially low-lying cerebellar tonsils. Since SIH is likely underdiagnosed, these findings could be interpreted as signs of CM1, leading to a misdiagnosis and an incorrect treatment pathway. Medical treatment, including steroids, bed rest, hydration caffeine, and a blind epidural blood patch, have been used in this condition with variable success rates. For some years, CSF venous fistulas have been described as the cause of SIH, and a specific diagnostic and therapeutic pathway have been proposed. The current literature on SIH with a focus on diagnosis, treatment, and differential diagnosis with CM1, is reviewed and discussed.

[Guidelines for the Diagnosis and Treatment of Spontaneous Intracranial Hypotension]

Spontaneous intracranial hypotension (SIH) is a syndrome characterized by disabling orthostatic headache, due to reduced cerebrospinal fluid (CSF) volume probably caused by a CSF fistula. It affects mostly women of working-age, although it is probably underdiagnosed. The aim of this article is to present a practical approach to the diagnosis and treatment of SIH. After a description of its symptoms and signs, we present a step-by-step approach to the confirmation of the diagnosis and treatment, considering different clinical scenarios. This is intended to guide clinical decision making, through a systematized and individualized management, aimed at the best interest of the patient.

Intraoperative Visualization of Flow in Direct Cerebrospinal Fluid-Venous Fistulas Using Intrathecal Fluorescein

BACKGROUND

Cerebrospinal fluid-venous fistulas (CVFs) are a rare cause of spontaneous intracranial hypotension. Intraoperatively, CVFs are not readily identifiable and difficult to differentiate from normal veins.

OBJECTIVE

To assess the utility of intrathecal fluorescein injection intraoperatively to visualize and identify the CVF.

METHODS

We report a case series of patients treated surgically for a CVF. After surgical exposure, we injected intrathecal fluorescein (5-10 mg) through a lumbar catheter, which we placed immediately before surgery.

RESULTS

Four patients with spontaneous intracranial hypotension with a suspected CVF underwent surgical ligation with adjunctive intrathecal fluorescein application. Intraoperative fluorescein injection confirmed the presence of a CVF in 3 cases. In 2 cases, we observed rapid fluorescein filling of a single epidural vein constituting the CVF. Other epidural vessels did not fill with fluorescein. In 1 case, fluorescein helped to identify a residual CVF after previous incomplete embolization. In the fourth case, no CVF was found intraoperatively. By contrast, a meningeal nerve root diverticulum was visualized, wrapped, and clipped.

CONCLUSION

We demonstrate for the first time the direct intraoperative visualization of CVF using intrathecal fluorescein. CVF can be identified intraoperatively using fluorescein dye, which can be a valuable adjunct for the surgeon confronted with this disease.

Continuous Epidural Saline Infusion for the Treatment of Spontaneous Intracranial Hypotension

OBJECTIVE

Spontaneous intracranial hypotension (SIH) is an increasingly recognized cause of orthostatic headache, but treatment strategies remain controversial. The epidural blood patch is a well-known and widely used treatment in patients with conservative treatment-resistant SIH, but symptoms may not improve even after multiple epidural blood patches, and resistant patients suffer from a lack of appropriate treatment options. Therefore, this study assessed the safety and efficacy of continuous epidural saline infusion (CESI) for SIH treatment.

METHODS

CESI was performed in 11 consecutive patients affected by conservative treatment-resistant SIH. Patient characteristics were obtained by reviewing medical records retrospectively. Headache intensity was assessed using the numerical rating scale (NRS), and changes in NRS before and after treatment were recorded.

RESULTS

The average treatment period for CESI was 21.3 ± 9.6 days, and the average follow-up period was 35.0 ± 30.2 months. CESI was without major complications or mortality, and no infections occurred, even without prophylactic antibiotics. The median NRS score before treatment was 10 points, improving to 5 points 1 day after infusion (P < 0.05), 2 points 1 week after infusion (P < 0.05), and 0 points at 3 months after infusion and the final follow-up. No patients have since experienced recurrence of orthostatic headaches.

CONCLUSIONS

CESI appears to be a safe and well-tolerated procedure for SIH. Further experience may demonstrate this technique to be a viable treatment option for SIH.

68Ga-DOTA PET for Diagnosis of Spinal Cerebrospinal Fluid Leaks

Spontaneous intracranial hypotension due to spinal cerebrospinal fluid (CSF) leakage causes substantial disease burden. In many patients, the course is protracted and refractory to conservative treatment, requiring targeted therapy. We propose PET of the CSF space with 68Ga-DOTA as a state-of-the-art approach to radionuclide cisternography (RC) and validate its diagnostic value. Methods: This study is a retrospective analysis of patients with suspected intracranial hypotension due to spinal CSF leaks and who underwent whole-body PET/CT at 1, 3, and 5 h after intrathecal lumbar injection of 68Ga-DOTA. Two independent raters unaware of the clinical data analyzed all scans for direct and indirect RC signs of CSF leakage. Volume-of-interest analysis was performed to assess the biologic half-life of the tracer in the CSF space and the ratio of decay-corrected activity in the CSF space at 5 and 3 h (simplified marker of tracer clearance). Comprehensive stepwise neuroradiologic work-up served as a reference; additional validation was provided by surgical findings and follow-up. Results: Of 40 consecutive patients, 39 patients with a working diagnosis of intracranial hypotension due to a spinal CSF leak (spontaneous, n = 31; postintervention, n = 8) could be analyzed. A spinal CSF leak was verified by the neuroradiologic reference method in 18 of 39 patients. As the only direct and indirect diagnostic signs, extrathecal tracer accumulation at the cervicothoracic junction (67% sensitivity and 90% specificity) and lack of activity over the cerebral convexities (5 h; 94% sensitivity and 67% specificity) revealed a high diagnostic value for spinal CSF leaks. Their combination provided little improvement (71% sensitivity and 95% specificity). Additional quantitative analyses yielded no benefit (94% sensitivity and 53% specificity for biological half-life; 94% sensitivity and 58% specificity for the ratio of total radioactivity within the CSF space at 5 and 3 h). The location of direct signs (extrathecal tracer accumulation) did not correlate with verified sites of spinal CSF leakage. Conclusion: We propose CSF PET with 68Ga-DOTA as a novel, fast, and convenient approach to RC for verification but not localization of spinal CSF leaks with high sensitivity and specificity. CSF PET may fulfill an important gatekeeper function for stratifying patients toward escalation (ruling in) or deescalation (ruling out) of diagnostic and therapeutic measures. Further prospective studies are needed to validate the present results and determine the potential of the methods to reduce the burden to patients.

CSF Flow and Spinal Cord Motion in Patients With Spontaneous Intracranial Hypotension: A Phase Contrast MRI Study

BACKGROUND AND OBJECTIVES

Spontaneous intracranial hypotension (SIH) is characterized by loss of CSF volume. We hypothesize that in this situation of low volume, a larger CSF flow and spinal cord motion at the upper spine can be measured by noninvasive phase contrast MRI.

METHODS

A prospective, age-, sex-, and body mass index (BMI)-matched controlled cohort study on patients with SIH presenting with spinal longitudinal extradural fluid collection (SLEC) was conducted from October 2021 to February 2022. Cardiac-gated 2D phase contrast MRI sequences were acquired at segment C2/C3, and C5/C6 for CSF flow, and spinal cord motion analysis. Data processing was fully automated. CSF flow and spinal cord motion were analyzed by peak-to-peak amplitude and total displacement per segment and heartbeat, respectively. Clinical data included age, height, BMI, duration of symptoms, Bern score according to Dobrocky et al., and type of the spinal CSF leak according to Schievink et al. Groups were compared via the Mann-Whitney U test; multiple linear regression analysis was performed to address possible relations.

RESULTS

Twenty patients with SIH and 40 healthy controls were analyzed; each group consisted of 70% women. Eleven patients with SIH presented with type 1 leak, 8 with type 2, and 1 was indeterminate. CSF flow per heartbeat was increased at C2/C3 (peak-to-peak amplitude 65.68 ± 18.3 vs 42.50 ± 9.8 mm/s, total displacement 14.32 ± 3.5 vs 9.75 ± 2.7 mm, p < 0.001, respectively). Craniocaudal spinal cord motion per heartbeat was larger at segment C2/C3 (peak-to-peak amplitude 7.30 ± 2.4 vs 5.82 ± 2.0 mm/s, total displacement 1.01 ± 0.4 vs 0.74 ± 0.4 mm, p = 0.006, respectively) and at segment C5/C6 (total displacement 1.41 ± 0.7 vs 0.97 ± 0.4 mm, p = 0.021).

DISCUSSION

SLEC-positive patients with SIH show higher CSF flow and higher spinal cord motion at the upper cervical spine. This increased craniocaudal motion of the spinal cord per heartbeat might produce increased mechanical strain on neural tissue and adherent structures, which may be a mechanism leading to cranial nerve dysfunction, neck pain, and stiffness in SIH. Noninvasive phase contrast MRI of CSF flow and spinal cord motion is a promising diagnostic tool in SIH.

TRIAL REGISTRATION INFORMATION

German Clinical Trials Register, identification number: DRKS00017351.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that noninvasive phase contrast MRI of the upper spine identifies differences in CSF flow and spinal cord motion in patients with SIH compared with healthy controls.

Progressive loss of hearing and balance in superficial siderosis due to occult spinal dural defects

PURPOSE

Superficial siderosis, a progressive, debilitating, neurological disease, often presents with bilateral impairment of auditory and vestibular function. We highlight that superficial siderosis is often due to a repairable spinal dural defect of the type that can also cause spontaneous intracranial hypotension.

METHODS

Retrospective chart review of five patients presenting with moderate to severe, progressive bilateral sensorineural hearing loss as well as vestibular loss. All patients had developed superficial siderosis from spinal dural defects: three after trauma, one after spinal surgery and one from a thoracic discogenic microspur.

RESULTS

The diagnosis was made late in all five patients; despite surgical repair in four, hearing and vestibular loss failed to improve.

CONCLUSIONS

In patients presenting with progressive bilateral sensorineural hearing loss, superficial siderosis should be considered as a possible cause. If these patients also have bilateral vestibular loss, cerebellar impairment and anosmia, then the diagnosis is likely and the inevitable disease progress might be halted by finding and repairing the spinal dural defect.

Spontaneous intracranial hypotension: updates from diagnosis to treatment

Spontaneous intracranial hypotension (SIH) is caused by spinal cerebrospinal fluid (CSF) leaks, which result in continued loss of CSF volume and multiple debilitating clinical manifestations. The estimated annual incidence of SIH is 5/100,000. Diagnostic methods have evolved in recent years due to improved understanding of pathophysiology and implementation of advanced myelographic techniques. Here, we synthesize recent updates and contextualize them in an algorithm for diagnosis and treatment of SIH, highlighting basic principles and points of practice variability or continued debate. This discussion includes finer points of SIH diagnosis, CSF leak classification systems, less common types and variants of CSF leaks, brain MRI Bern scoring, potential SIH complications, key technical considerations, and positioning strategies for different types of dynamic myelography. The roles of conservative measures, non-targeted or targeted blood patches, surgery, and recently developed endovascular techniques are presented.

Spontaneous Intracranial Hypotension: Controversies in Treatment

Spontaneous intracranial hypotension (SIH) is a disorder of low cerebrospinal fluid (CSF) volume secondary to CSF leakage through a dural defect along the neuraxis with an estimated incidence of 5 people per 100,000.Great debate persists on the optimal treatment of this pathology, and clinical results are often contradictory. SIH may be initially approached via conservative measures, such as bed rest that is often supplemented with hydration, caffeine, and theophylline, which overall relieve symptoms in a small subset of patients at 6 months. Epidural blood patching (EBP) is generally the next consideration in symptom management. It is the most commonly performed intervention for spinal CSF leaks, as the first option or following the failure of conservative treatment. Further procedures may be performed in the case of EBP partial or temporary response and if the spinal CSF leak has been definitively localized (Beck et al., Neurology 87:1220-26, 2016). In those cases, if the CSF leak is well localized, the surgical closure of the spinal CSF leak may be considered.SIH is a complex but treatable CSF disorder. Despite recent advances in the field of neuroimaging and the different therapeutic options available, the appropriate management remains controversial and should be tailored to the patient.

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.