Spontaneous Intracranial Hypotension Research Articles

The Impact of Venous Stenting on Symptoms and Quality of Life in Patients with Idiopathic Intracranial Hypertension and Spontaneous Cerebrospinal Fluid Leak

Abstract Background Elevated intracranial pressure can cause skull base defects and a spontaneous cerebrospinal fluid (CSF) leak. Venous sinus stenting (VSS) has emerged as a promising treatment option for patients with a CSF leak in the setting of idiopathic intracranial hypertension (IIH). There is a lack of literature on symptomatology and quality of life (QOL) after VSS for IIH patients with a CSF leak. This study explores the effects of VSS on symptoms and QOL in IIH patients with a CSF leak. Methods This is a retrospective study on patients who have IIH complicated by a CSF leak and underwent VSS. A QOL questionnaire was developed from the migraine disability assessment test and the PROMIS-PI was given to patients included in this study. Results A total of 10 patients were included in this study. Nine patients underwent endoscopic closure of CSF prior to stent placement and one patient was treated with VSS only. There was no evidence of CSF leak recurrence in this population following VSS. Headaches improved in 5/8, tinnitus in 5/6, and visual disturbance in 4/5 patients. Diamox was discontinued in seven out of eight patients after VSS. There was an improvement in headache-specific questions (p = 0.0140) and overall QOL (p = 0.0061) on the QOL questionnaire. Discussion This preliminary study demonstrates that VSS is effective in alleviating many symptoms in IIH patients with a CSF leak, especially headaches. Diamox may be able to be discontinued in many patients following VSS. No CSF leak recurrence was noted in this patient population.

Expert consensus on diagnosis and treatment of spontaneous intracranial hypotension(2024)

Spontaneous intracranial hypotension is a disease characterized by orthostatic headache caused by spinal cerebrospinal fluid leakage. Patients have to remain bedridden, which significantly affects their quality of life. In severe cases, complications such as subdural hematomas may occur. Clinical practice reveals a high rate of misdiagnosis and insufficient implementation of diagnostic and treatment measures. To improve clinical physicians' understanding of spontaneous intracranial hypotension and to standardize the diagnosis and treatment, the Neurologist Branch of the Chinese Medical Doctor Association and the Headache and Sensory Disorders Committee of the Chinese Research Hospital Association organized experts to develop a total of 30 recommendations on the clinical identification, examination processes, diagnostic criteria, treatment, and follow-up of spontaneous intracranial hypotension based on domestic and international clinical practices and recent literature evidence after extensive discussions.

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.

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.

Meningioma En Plaque Associated with Cerebrospinal Fluid Rhinorrhea: A Systematic Review of the Literature with Case Presentation

BackgroundMeningiomas are the most frequently diagnosed benign intracranial tumors. However, meningioma en plaque (MEP) is a rare subset accounting for 2.5% of all meningiomas and is characterized by flat, carpet-like proliferation along the dura, typically arising in the spheno-orbital region; therefore, causes proptosis, decreased visual acuity, and orbital pain. We present a unique case of MEP presenting with cerebrospinal fluid (CSF) rhinorrhea and conduct a systematic review of literature. MethodsFollowing PRISMA guidelines, a systematic search was conducted in PubMed and Embase databases. Keywords and standardized index terms related to MEP were used. The search was performed without restriction on the publication date. Screening, data extraction, and quality assessment were carried out. Data on demographics, clinical presentations, management modalities, and treatment outcomes were analyzed. ResultsThe search yielded 487 titles, with 36 studies eligible for inclusion. A total of 530 patients with MEP were reported, with a mean age of 50.1±11.62 years. Proptosis was the most common symptom (95%), followed by visual impairment (57.3%), orbital pain (38.3%), ophthalmoplegia (28.6%), and headache (23%). Our patient represented the only case with a spontaneous CSF leak. Surgical resection was performed in 85%, adjuvant radiotherapy in 15.7%, and one patient received primary radiotherapy, while 8 patients were closely followed up with no intervention. ConclusionMEP associated with spontaneous CSF rhinorrhea is extremely rare and poses diagnostic and therapeutic challenges. Conservative management for select cases of MEP can be a good choice, refraining the patient from surgical complications, especially for difficult-access skull base areas.

Brainstem changes causing reversible RBD in patients with spontaneous intracranial hypotension: a longitudinal neuroimaging study.

This study aimed to investigate the prevalence of REM sleep behavior disorder (RBD) in patients with spontaneous intracranial hypotension (SIH) and longitudinally assess the effects of epidural blood patch (EBP) treatment on brainstem structures using a neuroimaging approach. Twenty-two participants (10 SIH patients and 12 controls) underwent 3-Tesla Magnetic Resonance Imaging (MRI) scans. Midbrain and pons areas were measured on T1-weighted scans at baseline in both groups and three months after the first EBP in SIH patients to determine any MRI structural changes. The RBD Single-Questionnaire was used to screen SIH patients with symptoms suggestive of RBD for polysomnographic (PSG) recording. Half of the SIH patients (5/10) exhibited PSG-confirmed RBD. Baseline evaluation revealed deep brain swelling (DBS) on MRI scans in SIH-RBD patients. Following EBP treatment, significant changes in midbrain and pons morphometry were associated with complete clinical remission of RBD. Cross-sectional analysis showed larger midbrain and pons areas in SIH patients (with and without RBD) compared to controls. A midbrain area of 200 mm2 was identified as a cut-off value distinguishing SIH patients (with and without RBD) from controls individually. Longitudinal analysis demonstrated lower midbrain areas at follow-up compared to baseline in SIH patients. The study suggests that brainstem morphometric changes may underlie reversible RBD in SIH patients. Midbrain area measurement could serve as a dynamic biomarker for SIH, particularly in the presence of RBD, offering insights for clinical practice.

IIH, SIH and headache: Diagnosis and treatment update

Idiopathic intracranial hypertension (IIH) and spontaneous intracranial hypotension (SIH) are two major secondary headache disorders resulting from abnormal intracranial pressure (ICP). This short communication outlines the pathophysiology, diagnostic criteria, and management strategies for IIH and SIH. IIH predominantly affects obese women of childbearing age and presents with daily headaches, visual disturbances, and papilledema. It is characterized by elevated cerebrospinal fluid (CSF) pressure, with diagnosis supported by imaging and lumbar puncture. Treatment includes weight reduction, medications, and surgical interventions in refractory cases. SIH, conversely, is caused by spontaneous spinal CSF leaks and presents with acute orthostatic headaches. Diagnosis is supported by neuroimaging and lumbar puncture, revealing low CSF pressure. Treatment includes supported care, (targeted) epidural blood patch, with surgical repair considered in refractory cases. Advances in imaging and treatment have significantly improved outcomes for both conditions.

Assessing the Diagnostic Value of Brain White Matter Hyperintensities and Clinical Symptoms in Predicting the Detection of CSF Venous Fistula in Patients with Suspected Spontaneous Intracranial Hypotension.

Spontaneous intracranial hypotension (SIH) due to CSF venous fistula (CVF) is increasingly recognized as a secondary cause of headaches, with symptoms often overlapping with primary headache syndromes such as migraine. While brain MRI studies have focused on features indicative of SIH, findings that support an alternate headache etiology, such as the bifrontal white matter hyperintensities (WMH) often seen in migraines, have not been explored in this context. This study assesses 1) the quantity and distribution of WMH and 2) the presenting clinical features in patients with and without CVF found on dynamic decubitus CT myelography (dCTM). 72 consecutive patients underwent clinical workup for SIH due to suspected CVF, including pre-procedural brain and spine MRI followed by dCTM. Brain imaging features were analyzed, including Bern score, quantitative WMH burden, and WMH distribution. Demographics and clinical symptoms present at the time of presentation were recorded. Imaging features were compared between groups with and without CVF using parametric or nonparametric comparisons according to variable normality. Multivariate logistic regression explored the relationships between imaging features, clinical symptoms, and the presence of CVF. The cohort included 40 patients with (CVF+) and 32 patients without (CVF-), with no significant age or sex differences. CVF+ patients had significantly higher Bern scores and significantly fewer WMH. There were significant differences in the frequencies of WMH patterns between groups, with a migrainous pattern observed most frequently in CVF-patients. Logistic regression combining Bern score, WMH burden, and WMH pattern demonstrated a better fit for predicting CVF than using Bern score or WMH features alone. Fourteen clinical symptoms showed the greatest differences between CVF+ and CVF-groups. Logistic regression demonstrated a positive association between CVF detection and a pressure/throbbing headache quality, and negative associations for neck pain, facial pain, phonophobia, and anhedonia/depression. These findings suggest a negative association between CVF detection, increased burden of WMH, and a migrainous WMH pattern. Symptom analysis describes distinct clinical phenotypes, challenging orthostatic headache as a defining characteristic. These results support a comprehensive assessment of imaging and clinical presentations in the workup of suspected SIH. SIH = spontaneous intracranial hypotension; CVF = CSF venous fistula; WMH = white matter hyperintensities; dCTM = dynamic CT myelography; dDSM = dynamic digital subtraction myelography; PPV = positive predictive value; NPV = negative predictive value Received month day, year; accepted after revision month day, year.

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

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. 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. 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. 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.

Audiological Outcomes following Middle Cranial Fossa Repair of Spontaneous CSF Leaks.

Audiological Outcomes following Middle Cranial Fossa Repair of Spontaneous CSF Leaks.

Additional Diagnostic Value of Cone Beam CT Myelography Performed After Digital Subtraction Myelography for Detecting CSF-venous Fistulas.

CSF-venous fistulas are a common cause of spontaneous intracranial hypotension. The diagnosis and precise localization of these fistulas hinges on specialized myelographic techniques, which mainly include decubitus digital subtraction myelography and decubitus CT myelography (using either energy integrating or photon counting detector CT). A previous case series showed that cone beam CT myelography, performed as an adjunctive tool with digital subtraction myelography, increased the detection of CSF-venous fistulas. Here, we sought to determine the additive yield of cone beam CT myelography for CSF-venous fistula detection in a consecutive series of patients with spontaneous intracranial hypotension who underwent concurrent decubitus digital subtraction myelography and cone beam CT myelography. We retrospectively searched our institutional database for all consecutive patients who underwent decubitus digital subtraction myelography with adjunctive cone beam CT myelography between 8/5/2021 and 8/5/2024. We excluded any patients harboring extradural CSF on spine imaging, not meeting International Classification of Headache Disorders (3rd edition) criteria for spontaneous intracranial hypotension, or not having undergone technically successful cone beam CT myelography in combination with digital subtraction myelography. All myelographic images were independently reviewed by two neuroradiologists. We calculated the diagnostic yield of both myelographic tests for localizing a CSF-venous fistula. We identified 100 patients who underwent decubitus digital subtraction myelography with adjunctive cone beam CT. We excluded 15 patients based on above criteria. 59/85 patients had a single definitive CSF-venous fistula. Among positive cases, the fistula was visible on digital subtraction myelography in 38/59 patients and visible on cone beam CT myelography in 59/59 patients. In 26/85 patients, no definitive fistula was identified on either modality. Cone beam CT myelography increased the diagnostic yield for CSF-venous fistula detection and may be a useful addition to digital subtraction myelography. CB-CTM = cone beam CT myelography; CVF = CSF-venous fistula; DSM = digital subtraction myelography; EID-CTM = energy integrating detector CT myelography; PCD CTM = photon counting detector CT myelography; SIH = spontaneous intracranial hypotension.

Spontaneous Intracranial Hypotension in Children: A Multi-Institutional Review of Spinal CSF Leaks Localized on Advanced Myelography.

Spontaneous intracranial hypotension is an increasingly recognized syndrome caused by a spinal CSF leak, with most reported cases occurring in adults. The use of specialized or advanced myelography to localize spinal CSF leaks has evolved substantially in recent years, particularly since the initial description of CSF-venous fistulas in 2014. To our knowledge, no prior series have evaluated the use of specialized myelographic techniques to localize CSF leaks in children with spontaneous intracranial hypotension, likely because the disease is rare in this patient population. This issue may be compounded by a hesitation to perform invasive procedures in children. In this clinical report, we conducted a multi-institutional review of pediatric patients with spontaneous spinal CSF leaks localized using advanced myelographic techniques, such as prone and decubitus digital subtraction and CT myelography, as well as dynamic CT myelography. We report the clinical features of these patients, as well as imaging findings, types of leaks discovered, and method of treatment. We found that the primary types of spontaneous spinal CSF leaks that occur in adults, including dural tears and CSF fistulas, can be seen in children, too. Furthermore, we show that specialized myelographic techniques can successfully localize these leaks and facilitate effective targeted treatment.

More than a headache-somatic and mental symptom burden in spontaneous intracranial hypotension before and after surgical treatment.

Patients with spontaneous intracranial hypotension (SIH) frequently present with several symptoms and impaired mental health. This study systematically investigates the somatic and mental symptom burden of SIH and the effect of surgical treatment. In this single-center retrospective study, patients with surgical closure of a spinal cerebrospinal fluid leak between September 2022 and July 2023 completed the Somatic Symptom Scale (SSS-8), the Somatic Symptom Disorder - B Criteria Scale (SSD-12), and the Patient Health Questionnaire (PHQ-8) preoperatively and three and 6 months postoperatively. Fifty-seven patients were included. All three scores showed clearly pathological values before surgery (SSS-8: 12 [IQR 6.5-16], SSD-12: 26 [IQR 19.5-33.5], PHQ-8: 11 [IQR 6.5-15]) representing a high somatic symptom burden and relevant current depression. After surgery, there was a significant and sustainable improvement (SSS-8: 8 [IQR 3-11.75], SSD-12: 12.5 [IQR 5-21.75], PHQ-8: 4.5 [IQR 2-9], p < 0.001, respectively) that exceeded the minimal clinically important difference for every score. SIH presents with high somatic and mental symptom burden. Surgical treatment leads to a relevant improvement of somatic and depressive symptoms. However, even after surgical success some patients still exhibit elevated depressive scores. Depressive symptoms might be added to the typical symptomatology of SIH.

Jugular venous narrowing and spontaneous spinal cerebrospinal fluid leaks: A case-control study exploring association and proposed mechanism.

Spontaneous skull base cerebrospinal fluid leaks (CSFLs) are associated with increased intracranial pressure in idiopathic intracranial hypertension (IIH) and hypothesized to relate to skull base erosions due to increased CSF pressure. Given the increasing recognition of internal jugular venous stenosis (IJVS) as a cause of intracranial hypertension (IH), we evaluated the relationship between spinal CSFL and venous causes of IH. The spinal CSFL database at a single institution was assessed to identify 12 consecutive spontaneous, non-traumatic spinal CSFL patients with CTV data. Exclusion criteria included documented IIH and iatrogenic CSFL. Demographics, clinical parameters, imaging characteristics, and IJV manometry results were recorded. Internal jugular venous stenosis was graded as: none (0-10%), mild (10-50%), moderate (50-80%), severe (>80-99%), and occluded (100%). Twelve consecutive patients who presented with cerebrovascular accidents without CSFL, matched by age and sex, were similarly analyzed as a control group. STROBE guidelines were used in reporting results. All CSFL patients had IJVS (83.3% bilateral, 33.3% severe) compared to 41.7% of the control group (33.3% bilateral, 16.7% severe-occluded); p = 0.04. All CSFL patients with available venogram manometry data had at least unilateral IJV gradients. Most patients presented with modified Rankin score (mRS) of 1 (66.7%), but in those with higher mRS, medical and/or surgical interventions were associated with decreased morbidity. Spontaneous spinal CSFL was associated with IJVS in patients not meeting IIH criteria. Persistently high CSF pressure resulting in CSFL may cause opening pressure to be falsely normal or low. Internal jugular venous stenosis may be a viable target in recurrent CSFL management and improve morbidity.

Myelographic Techniques for the Localization of CSF-Venous Fistulas: Updates in 2024.

CSF-venous fistulas (CVFs) are a common cause of spontaneous intracranial hypotension. Despite their relatively frequent occurrence, they can be exceedingly difficult to detect on imaging. Since the initial description of CVFs in 2014, the recognition and diagnosis of this type of CSF leak has continually increased. As a result of multi-institutional efforts, a wide spectrum of imaging modalities and specialized techniques for CVF detection is now available. It is important for radiologists to be familiar with the multitude of available techniques, because each has unique advantages and drawbacks. In this article, we review the spectrum of imaging modalities available for the detection of CVFs, explain the advantages and disadvantages of each, provide typical imaging examples, and discuss provocative maneuvers that may improve the conspicuity of CVFs. Discussed modalities include conventional CT myelography, dynamic myelography, digital subtraction myelography, conebeam CT myelography, decubitus CT myelography by using conventional energy-integrating detector scanners, decubitus photon counting CT myelography, and intrathecal gadolinium MR myelography. Additional topics to be discussed include optimal patient positioning, respiratory techniques, and intrathecal pressure augmentation.

Mechanical Thrombectomy in Cerebral Venous Thrombosis Caused by Spontaneous Intracranial Hypotension: A Case Report with Novel Pathological Findings of Fibrin/Platelet-predominant Thrombus

This case report presents pathological findings in a rare case of cerebral venous thrombosis (CVT) caused by spontaneous intracranial hypotension (SIH) that was treated successfully with mechanical thrombectomy. The etiologies and prognosis of CVT vary, and CVT resulting from SIH is particularly uncommon and challenging to diagnose and manage. In this case, magnetic resonance imaging revealed signs consistent with both SIH and CVT, which contributed to the patient’s worsening weakness. The patient was treated with a combination of endovascular thrombectomy and epidural blood patch, followed by anticoagulation therapy, and recovered without any complications. A pathological analysis of the retrieved thrombus using hematoxylin and eosin staining showed a high proportion of fibrin and platelets, which could shed light on the mechanism of CVT induced by SIH under conditions of low blood flow due to venous engorgement.

Ventral Thoracic Cerebrospinal Fluid Leak Repair in Spontaneous Intracranial Hypotension Complicated by Superficial Siderosis: 2-Dimensional Operative Video.

Ventral Thoracic Cerebrospinal Fluid Leak Repair in Spontaneous Intracranial Hypotension Complicated by Superficial Siderosis: 2-Dimensional Operative Video.

Density and Time Characteristics of CSF-venous fistulas on CT myelography in Patients with Spontaneous Intracranial Hypotension.

The conspicuity of CSF-venous fistulas (CVF) on specialized myelographic imaging protocols varies, and the factors that determine their visibility have not yet been extensively studied. The purpose of this study was to determine the relative effect of two variables on CVF visibility: timing of imaging and intrathecal contrast density. Retrospective cohort of 24 patients with spontaneous intracranial hypotension due to a CVF who underwent a total of 34 CT myelographies. All CTM acquisitions that included the level of the known definite CVF were evaluated for (1) time passed after injection of contrast, (2) attenuation of the adjacent subarachnoid space, (3) subjective visibility of the CVF on that series,(4) attenuation of the corresponding draining vein and (5) contrast dose used. A total of 131 acquisitions included the level of the known CVFs. Attenuation values of the thecal sac were significantly higher in acquisitions where the CVFs were definitely visible (average 2283 HU) than on acquisitions where the CVFs were equivocal or not visible (764 HU and 583 HU respectively). No significant difference was shown in the timing of the acquisitions between the three groups (12.8 min, 20.4 min and 17.5 min respectively). Multivariate linear regression showed thecal sac density to be the only independent predictor of the density of the CVF draining vein, while time passed after contrast injection was not independently correlated. Intrathecal contrast density has a strong positive relationship with the visibility of CVF. Timing of the acquisition was not an independent predictor of CVF visibility under our acquisition protocolABBREVIATIONS: LDCTM = lateral decubitus CT myelography; CVF = CSF-venous fistula; IOCM = iodinated contrast media.

Different Glymphatic Kinetics in Spontaneous Intracranial Hypotension.

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. 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. 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. 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.

Reappraisal of the Previously Described False Localizing Sign at C1-2 in Cases of Spontaneous Intracranial Hypotension

BACKGROUND AND OBJECTIVES: We present an illustrative case of spontaneous intracranial hypotension (SIH) in the setting of a suspected C1-2 cerebrospinal fluid (CSF) leak that was successfully treated with muscle, collagen, and epidural blood patch. We examined the literature to identify similar cases reporting Cl-2 retrospinal fluid collections identified on imaging in the setting of SIH and quantified the success of targeted treatment to this area despite previous reports that caution about a “C1-2 false localizing sign.” METHODS: A systematic search was performed identifying cases of SIH resulting from CSF leak with C1-2 fluid collection observed on imaging. PubMed, Google Scholar, and Web of Science were queried, and articles were screened for possible inclusion by 2 authors and supervised by the senior author. RESULTS: In total, 28 studies were included with a total of 32 patients. The number of patients in each study with C1-2 fluid collections, number of patients with fluid collections at multiple levels, specific intervention used, and outcomes of each intervention were recorded, with a focus on whether treatment occurred at the levels exhibiting fluid signal. CONCLUSION: Although the C1-2 fluid signal in SIH has previously been described as a “false localizing sign,” our study indicates that treating this level as the source of CSF leak results in successful and durable outcomes. Most SIH cases with signal at C1-2 did not have a fluid signal at any other level and were treated successfully and most commonly through epidural blood patch at the C1-2 level. Symptom resolution was also reported after direct repair of C1-2 CSF leaks through primary closure, Gelfoam patch, and muscle fragment with fibrin. In patients with SIH, C1-2 fluid signal, and no other source of CSF leak identified on imaging, surgical intervention at the C1-2 level seemed to have a high success rate.