Abstracts 2021

AUTHORS: Jessica L. Houk MD, Timothy J. Amrhein MD, Linda Gray MD, Michael D. Malinzak MD, PhD, and Peter G. Kranz MD
CITATION: J Neurosurg. 2021 Oct 29:1-8. doi: 10.3171/2021.6.JNS211010. Epub ahead of print. PMID: 34715671. 

OBJECTIVE: Chiari malformation type 1 (CM-1) and spontaneous intracranial hypotension (SIH) are causes of headache in which cerebellar tonsillar ectopia (TE) may be present. An accurate method for differentiating these conditions on imaging is needed to avoid diagnostic confusion. Here, the authors sought to determine whether objective measurements of midbrain morphology could distinguish CM-1 from SIH on brain MRI.

METHODS USED: This is a retrospective case-control series comparing neuroimaging in consecutive adult subjects with CM-1 and SIH. Measurements obtained from brain MRI included previously reported measures of brain sagging: TE, slope of the third ventricular floor (3VF), pontomesencephalic angle (PMA), mamillopontine distance, lateral ventricular angle, internal cerebral vein–vein of Galen angle, and displacement of iter (DOI). Clivus length (CL), an indicator of posterior fossa size, was also measured. Measurements for the CM-1 group were compared to those for the entire SIH population (SIH_all) as well as a subgroup of SIH patients with > 5 mm of TE (SIH_TE subgroup).

RESULTS OF THE STUDY: Highly significant differences were observed between SIH_all and CM-1 groups in the following measures: TE (mean ± standard deviation, 3.1 ± 5.7 vs 9.3 ± 3.5 mm), 3VF (−16.8° ± 11.2° vs −2.1° ± 4.6°), PMA (44.8° ± 13.1° vs 62.7° ± 9.8°), DOI (0.2 ± 4.1 vs 3.8 ± 1.6 mm), and CL (38.3 ± 4.5 vs 44.0 ± 3.3 mm; all p < 0.0001). Eight (16%) of 50 SIH subjects had TE > 5 mm; in this subgroup (SIH_TE), a cutoff value of < −15° for 3VF and < 45° for PMA perfectly discriminated SIH from CM-1 (sensitivity and specificity = 1.0). DOI showed perfect specificity (1.0) in detecting SIH among both groups. No subjects with SIH had isolated TE without other concurrent findings of midbrain sagging.

STUDY CONCLUSIONS: Measures of midbrain sagging, including cutoff values for 3VF and PMA, discriminate CM-1 from SIH and may help to prevent misdiagnosis and unnecessary surgery.

ABBREVIATIONS: 3VF = slope of the third ventricular floor; CL = clivus length; CM-1 = Chiari malformation type 1; CVF = CSF-venous fistula; DOI = displacement of iter; LVA = lateral ventricular angle; MPD = mamillopontine distance; PMA = pontomesencephalic angle; SIH = spontaneous intracranial hypotension; TE = tonsillar ectopia; VHA = venous hinge angle.

PMID: 34715671 
DOI: 10.3171/2021.6.JNS211010

AUTHORS: Schievink WI, Maya MM, Moser FG, Simon P, Nuño M.
CITATION: Cephalalgia. 2021 Sep 23:3331024211048510. doi:10.1177/03331024211048510. Epub ahead of print. PMID: 34553617.

STUDY BACKGROUND: Spontaneous intracranial hypotension is diagnosed with an increasing frequency, but epidemiologic data are scarce. The aim of this study was to determine the incidence rate of spontaneous intracranial hypotension in a defined population.

METHODS USED: Using a prospectively maintained registry, all patients with spontaneous intracranial hypotension residing in Beverly Hills, California, evaluated at our Medical Center between 2006 and 2020 were identified in this population-based incidence study. Our Medical Center is a quaternary referral center for spontaneous intracranial hypotension and is located within 1.5 miles from downtown Beverly Hills.

RESULTS OF THE STUDY: A total of 19 patients with spontaneous intracranial hypotension were identified. There were 12 women and seven men with a mean age of 54.5 years (range, 28 to 88 years). The average annual incidence rate for all ages was 3.7 per 100,000 population (95% confidence interval [CI]: 2.0 to 5.3), 4.3 per 100,000 for women (95% CI, 1.9 to 6.7) and 2.9 per 100,000 population for men (95% CI, 0.8 to 5.1).

STUDY CONCLUSION: This study, for the first time, provides incidence rates for spontaneous intracranial hypotension in a defined population.

PMID: 34553617
DOI: 10.1177/03331024211048510

AUTHORS: Osawa I, Kozawa E, Mitsufuji T, Yamamoto T, Araki N, Inoue K, Niitsu M.
CITATION: Eur J Radiol Open. 2021 May 13;8:100352. doi: 10.1016/j.ejro.2021.100352. eCollection 2021.

PURPOSE OF THE STUDY: To evaluate the clinical utility of intravenous gadolinium-enhanced heavily T2-weighted 3D fluid-attenuated inversion recovery (HT2-FLAIR) imaging for identifying spinal cerebrospinal fluid (CSF) leaks in patients with spontaneous intracranial hypotension (SIH).

METHODS USED: Patients with SIH underwent MR myelography and post-contrast HT2-FLAIR imaging after an intravenous gadolinium injection. Two types of CSF leaks (epidural fluid collection and CSF leaks around the nerve root sleeve) at each vertebral level were compared between the 2 sequences. The total numbers of CSF leaks and vertebral levels involved were recorded for the whole spine. The sequence that was superior for the overall visualization of epidural and paraspinal fluid collection was then selected.

RESULTS OF THE STUDY: Nine patients with SIH were included in the present study. HT2-FLAIR imaging was equivalent or superior to MR myelography at each level for detecting the 2 types of CSF leaks. In the 2 types of CSF leaks, the total numbers of CSF leaks and levels involved were higher on HT2-FLAIR images than on MR myelography, while no significant difference was observed for CSF leaks around the nerve root sleeve. In all 9 patients, HT2-FLAIR imaging was superior to MR myelography for the overall visualization of epidural and paraspinal fluid collection.

STUDY CONCLUSION: Intravenous gadolinium-enhanced HT2-FLAIR imaging was superior to MR myelography for the visualization of CSF leaks in patients with SIH. This method can be useful for identifying spinal CSF leaks.

PMID: 34026946 
PMCID: PMC8134034
DOI: 10.1016/j.ejro.2021.100352

AUTHORS: Shlobin NA, Shah VN, Chin CT, Dillon WP, Tan LA.
CITATION: Neurosurgery. 2021 Apr 15;88(5):931-941. doi: 10.1093/neuros/nyaa558.

BACKGROUND: Spontaneous intracranial hypotension (SIH) is usually caused by a spinal cerebrospinal fluid (CSF) leak. CSF-venous fistula is an underdiagnosed cause of spinal CSF leak, as it is challenging to identify on myelography.

OBJECTIVE OF THE STUDY: To review existing literature to summarize common presentations, diagnostic imaging modalities, and current treatment strategies for CSF-venous fistulas.

STUDY METHODS: We conducted a systematic review using PubMed, Embase, Scopus, and Web of Science databases to identify studies discussing CSF-venous fistulas. Titles and abstracts were screened. Studies meeting prespecified inclusion criteria were reviewed in full.

RESULTS OF THE STUDY: Of 180 articles identified, 16 articles met inclusion criteria. Individual patient data was acquired from 7 studies reporting on 18 patients. CSF-venous fistula most frequently presented as positional headache. Digital subtraction myelography provided greatest detection of CSF-venous fistula in the lateral decubitus position and detected CSF-venous fistula in all individual patient cases. Dynamic computed tomography (CT) myelogram enabled detection and differentiation of CSF-venous fistulas from low-flow epidural leaks. The majority of fistulas were in the thoracic spine and slightly more common on the right. Epidural blood patch (EBP) provided temporary or no relief in all individual patients. Resolution or improvement of clinical symptoms and radiologic normalization were observed in all surgically treated patients.

STUDY CONCLUSION: Although rare, CSF-venous fistula is an important cause of spinal CSF leak contributing to SIH. Dynamic CT myelogram and digital subtraction myelography, particularly in the lateral decubitus position, are the most accurate and effective diagnostic imaging modalities. EBPs often provide only transient relief, while surgical management is preferred.

PMID: 33438744
DOI: 10.1093/neuros/nyaa558

AUTHORS: Chan TLH, Vuong K, Chugh T, Carroll I.
CITATION: Heliyon. 2021 Apr 19;7(4):e06795. doi: 10.1016/j.heliyon.2021.e06795. eCollection 2021 Apr.

Study Abstract
Cerebellar tonsillar descent can be seen on head magnetic resonance imaging in both Chiari malformation type 1 and spinal cerebrospinal fluid leak creating the potential for misdiagnosis. We report five cases of spinal cerebrospinal fluid leak at Stanford University initially misdiagnosed and treated as Chiari malformation type 1 based on cerebellar tonsillar descent demonstrated on imaging. All five cases had sustained relief at the 6-month follow up visit from epidural blood patches for the treatment of spinal cerebrospinal leak after unsuccessful suboccipital decompression surgeries. A misdiagnosis of Chiari malformation type 1 in patients with spinal cerebrospinal fluid leak may lead to unnecessary surgeries instead of the less invasive treatment, such as epidural blood patches. It is imperative to consider a spinal cerebrospinal fluid leak in the differential based on clinical-radiological correlation and not solely on cerebellar tonsillar descent demonstrated on imaging.

PMID: 33981879
PMCID: PMC8082209
DOI: 10.1016/j.heliyon.2021.e06795

AUTHORS: D’Antona L, Jaime Merchan MA, Vassiliou A, Watkins LD, Davagnanam I, Toma AK, Matharu
CITATION: JAMA Neurol. 2021 Mar 1;78(3):329-337. doi: 10.1001/jamaneurol.2020.4799.

IMPORTANCE OF THE STUDY: Spontaneous intracranial hypotension (SIH) is a highly disabling but often misdiagnosed disorder. The best management options for patients with SIH are still uncertain.

OBJECTIVE OF THE STUDY: To provide an objective summary of the available evidence on the clinical presentation, investigations findings, and treatment outcomes for SIH.

STUDY DATA SOURCES: Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline-compliant systematic review and meta-analysis of the literature on SIH. Three databases were searched from inception to April 30, 2020: PubMed/MEDLINE, Embase, and Cochrane. The following search terms were used in each database: spontaneous intracranial hypotension, low CSF syndrome, low CSF pressure syndrome, low CSF volume syndrome, intracranial hypotension, low CSF pressure, low CSF volume, CSF hypovolemia, CSF hypovolaemia, spontaneous spinal CSF leak, spinal CSF leak, and CSF leak syndrome.

STUDY SELECTION: Original studies in English language reporting 10 or more patients with SIH were selected by consensus.
Data extraction and synthesis: Data on clinical presentation, investigations findings, and treatment outcomes were collected and summarized by multiple observers. Random-effect meta-analyses were used to calculate pooled estimates of means and proportions.

MAIN OUTCOMES AND MEASURES OF THE STUDY: The predetermined main outcomes were the pooled estimate proportions of symptoms of SIH, imaging findings (brain and spinal imaging), and treatment outcomes (conservative, epidural blood patches, and surgical).

RESULTS OF THE STUDY: Of 6878 articles, 144 met the selection criteria and reported on average 53 patients with SIH each (range, 10-568 patients). The most common symptoms were orthostatic headache (92% [95% CI, 87%-96%]), nausea (54% [95% CI, 46%-62%]), and neck pain/stiffness (43% [95% CI, 32%-53%]). Brain magnetic resonance imaging was the most sensitive investigation, with diffuse pachymeningeal enhancement identified in 73% (95% CI, 67%-80%) of patients. Brain magnetic resonance imaging findings were normal in 19% (95% CI, 13%-24%) of patients. Spinal neuroimaging identified extradural cerebrospinal fluid in 48% to 76% of patients. Digital subtraction myelography and magnetic resonance myelography with intrathecal gadolinium had high sensitivity in identifying the exact leak site. Lumbar puncture opening pressures were low, normal (60-200 mm H2O), and high in 67% (95% CI, 54%-80%), 32% (95% CI, 20%-44%), and 3% (95% CI, 1%-6%), respectively. Conservative treatment was effective in 28% (95% CI, 18%-37%) of patients and a single epidural blood patch was successful in 64% (95% CI, 56%-72%). Large epidural blood patches (>20 mL) had better success rates than small epidural blood patches (77% [95% CI, 63%-91%] and 66% [95% CI, 55%-77%], respectively).

STUDY CONCLUSIONS AND RELEVANCE: Spontaneous intracranial hypotension should not be excluded on the basis of a nonorthostatic headache, normal neuroimaging findings, or normal lumbar puncture opening pressure. Despite the heterogeneous nature of the studies available in the literature and the lack of controlled interventional studies, this systematic review offers a comprehensive and objective summary of the evidence on SIH that could be useful in guiding clinical practice and future research.

PMID: 33393980
PMCID: PMC7783594 
DOI: 10.1001/jamaneurol.2020.4799

AUTHORS: Malinzak MD, Kranz PG, Gray L, Amrhein TJ
CITATION: Neurol Clin Pract Mar 2021. First pub March 3, 2021, DOI:10.1212/CPJ.0000000000001061

Study Abstract
Spinal CSF-venous fistulas (CVF) were described in 2014 and are now recognized as an important etiology of spontaneous intracranial hypotension (SIH) 1-3. Surgical ligation is highly effective for treating CVFs4. Given the relatively recent discovery of this entity, long-term follow up on treated cases has not been available, however, surgery has generally been considered definitive treatment. We report four cases of SIH in which CVFs have recurred or developed de novo at a different spinal level following complete surgical ligation of the primary lesion. In all cases, the new CVF was not present on any pre-surgical imaging.

PMID:
DOI: 10.1212/CPJ.0000000000001061

AUTHORS: Park JY, Ro YJ, Leem JG, Shin JW, Oh Y, Choi SS.
CITATION: J Clin Med. 2021 Feb 28;10(5):922. doi: 10.3390/jcm10050922.

Study Abstract
An autologous epidural blood patch (EBP) is a mainstay of treatment in patients with spontaneous intracranial hypotension (SIH). EBP, however, is less effective for SIH than post-dural puncture headaches. Therefore, patients with SIH frequently require an additional EBP. The aim of this study was to identify factors associated with poor response to EBP. This single-center retrospective observational study used the institutional registry records of 321 patients who underwent EBP between September 2001 and March 2016. Patients were divided into two groups, a poor responder group, consisting of patients who underwent EBP at least three times or more, and a good responder group of patients who experienced sufficient symptom relief after two or fewer EBP. The demographic characteristics, clinical features, radiologic findings, procedural data, and laboratory data were analyzed. Univariate analysis showed that the neutrophil-to-lymphocyte ratio (NLR; p = 0.004) and platelet-to-lymphocyte ratio (p = 0.015) were significantly lower in poor than in good responders. Multivariate analysis found that NLR was the only independent factor associated with a poor response (odds ratio = 0.720; p = 0.008). These findings indicate that a low NLR was associated with three or more EBP administrations for the sufficient improvement of symptoms in patients with SIH.

PMID: 33670838
DOI: 10.3390/jcm10050922
Open Access

AUTHORS: Mamlouk MD, Shen PY, Sedrak MF, Dillon WP.
CITATION: Radiology. 2021 Mar 2:204231. doi: 10.1148/radiol.2021204231. Online ahead of print.

BACKGROUND: Cerebrospinal fluid-venous fistulas (CVFs) are one of the less common etiologic causes of spontaneous intracranial hypotension. CVFs are most commonly treated with open surgical ligation and have reportedly not responded well to percutaneous treatments. Purpose To study treatment outcomes of CT-guided fibrin glue occlusion for CVFs.

STUDY MATERIALS AND METHODS: Retrospective review of medical records from two institutions was performed for all patients with CVFs who underwent CT-guided percutaneous fibrin glue occlusion from March to October 2020. CVFs were assessed for resolution or persistence at posttreatment decubitus CT myelography (CTM). Pre- and posttreatment brain MRI scans were reviewed for principal signs of spontaneous intracranial hypotension. Clinical symptoms were documented before and immediately after therapy, and the current symptoms to date after fibrin glue occlusion were documented.

RESULTS OF THE STUDY: CT-guided fibrin glue occlusion was performed in 13 patients (mean age, 62 years ± 14 [standard deviation]; eight women) with CVFs. Ten of 10 patients who underwent final posttreatment decubitus CTM examinations showed CVF resolution. All 13 patients showed improvement on posttreatment brain MRI scans. All 13 patients are currently asymptomatic, although three patients were asymptomatic before fibrin glue occlusion.

CONCLUSION OF THE STUDY: CT-guided fibrin glue occlusion is an effective treatment for patients with cerebrospinal fluid-venous fistulas (CVFs). Direct fibrin glue administration within the CVF may be one of the key factors for success. Further studies are needed to determine the long-term efficacy of this treatment.

PMID: 33650903
DOI: 10.1148/radiol.2021204231

AUTHORS: Signorelli F, Caccavella VM, Giordano M, Ioannoni E, Caricato A, Polli FM, Olivi A, Montano N.
CITATION: Neurosurg Rev. 2021 Feb 21. doi: 10.1007/s10143-021-01505-5. Online ahead of print.

Study Abstract
Spontaneous intracranial hypotension (SIH) is an often misdiagnosed condition resulting from non-iatrogenic cerebrospinal fluid (CSF) hypovolemia, typically secondary to spinal CSF leakage. Patients commonly present with posture-related headache, nausea, and vomiting. Following failure of conservative measures, epidural blood patching (EBP) is the most commonly performed intervention for spinal CSF leaks. The authors performed a systematic review and meta-analysis of existing literature to evaluate the role of different factors possibly affecting the efficacy of the EBP procedure. In accordance with the PRISMA guidelines, PubMed/Medline and SCOPUS databases were searched. Six eligible articles were retrieved. Five hundred patients were treated for SIH with EBP, of which 300 reported good response defined as complete remission of symptoms within 48 h after the first EBP requiring no further invasive treatment. Among the factors available for meta-analysis, none was found to be statistically significant in affecting the efficacy of the EBP procedure. A largely symmetrical funnel plot is reported for all the variables evaluated, indicating that publication bias did not play a significant role in the observed effects. The current knowledge about SIH and the EBP is scarce. The existing literature is contradictory and insufficient to aid in clinical practice. More studies are needed to draw significant conclusions that may help in the identification of patients at higher risk of EBP failure, who may benefit from different approaches.

PMID: 33611638 
DOI: 10.1007/s10143-021-01505-5

AUTHORS: Caton MT Jr, Laguna B, Soderlund KA, Dillon WP, Shah VN.
CITATION: AJNR Am J Neuroradiol. 2021 Feb 18. doi: 10.3174/ajnr.A7018. Online ahead of print.

BACKGROUND AND PURPOSE OF THE STUDY: Craniospinal space compliance reflects the distensibility of the spinal and intracranial CSF spaces as a system. Craniospinal space compliance has been studied in intracranial pathologies, but data are limited in assessing it in spinal CSF leak. This study describes a method to estimate craniospinal space compliance using saline infusion during CT myelography and explores the use of craniospinal space compliance and pressure-volume curves in patients with suspected cerebrospinal-venous fistula.

STUDY MATERIALS AND METHODS: Patients with suspected cerebrospinal-venous fistula underwent dynamic CT myelography. During the procedure, 1- to 5-mL boluses of saline were infused, and incremental changes in CSF pressure were recorded. These data were used to plot craniospinal space compliance curves. We calculated 3 quantitative craniospinal space compliance parameters: overall compliance, compliance at opening pressure, and the pressure volume index. These variables were compared between patients with confirmed cerebrospinal-venous fistula and those with no confirmed source of CSF leak.

RESULTS OF THE STUDY: Thirty-four CT myelograms in 22 patients were analyzed. Eight of 22 (36.4%) patients had confirmed cerebrospinal-venous fistulas. Bolus infusion was well-tolerated with no complications and transient headache in 2/34 (5.8%). Patients with confirmed cerebrospinal-venous fistulas had higher compliance at opening pressure and overall compliance (2.6 versus 1.8 mL/cm H₂0, P < .01). There was no difference in the pressure volume index (77.5 versus 54.3 mL, P = .13) between groups.

CONCLUSIONS OF THE STUDY: A method of deriving craniospinal space compliance curves using saline intrathecal infusion is described. Preliminary analysis of craniospinal space compliance curves provides qualitative and quantitative information about pressure-volume dynamics and may serve as a diagnostic tool in patients with known or suspected cerebrospinal-venous fistulas.

PMID: 33602750
DOI: 10.3174/ajnr.A7018

AUTHORS: Brinjikji W, Savastano LE, Atkinson JLD, Garza I, Farb R, Cutsforth-Gregory JK.
CITATION: AJNR Am J Neuroradiol. 2021 Feb 4. doi: 10.3174/ajnr.A7014. Online ahead of print.

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

PMID: 33541895
DOI: 10.3174/ajnr.A7014

AUTHORS: Schievink WI, Maya M, Prasad RS, Wadhwa VS, Cruz RB, Moser FG, Nuno M.
CITATION: Headache. 2021 Jan 23. doi: 10.1111/head.14048. Online ahead of print.

OBJECTIVE OF THE STUDY: To determine the occurrence of cerebrospinal fluid (CSF)-venous fistulas, a type of spinal CSF leak that cannot be detected with routine computerized tomography myelography, among patients with orthostatic headaches but normal brain and spine magnetic resonance imaging.

BACKGROUND: Spontaneous spinal CSF leaks cause orthostatic headaches but their detection may require sophisticated spinal imaging techniques.

STUDY METHODS: A prospective cohort study of patients with orthostatic headaches and normal brain and conventional spine imaging who underwent digital subtraction myelography (DSM) to look for CSF-venous fistulas, between May 2018 and May 2020, at a quaternary referral center for spontaneous intracranial hypotension.

RESULTS OF THE STUDY: The mean age of the 60 consecutive patients (46 women and 14 men) was 46 years (range, 13-83 years), who had been suffering from orthostatic headaches between 1 and 180 months (mean, 43 months). DSM demonstrated a spinal CSF-venous fistula in 6 (10.0%; 95% confidence interval [CI]: 3.8-20.5%) of the 60 patients. The mean age of these five women and one man was 50 years (range, 41-59 years). Spinal CSF-venous fistulas were identified in 6 (19.4%; 95% CI: 7.5-37.5%) of 31 patients with spinal meningeal diverticula but in none (0%; 95% CI: 0-11.9%) of the 29 patients without spinal meningeal diverticula (p = 0.024). All CSF-venous fistulas were located in the thoracic spine. All patients underwent uneventful surgical ligation of the fistula. Complete and sustained resolution of symptoms was obtained in five patients, while in one patient, partial recurrence of symptoms was noted 3 months postoperatively.

CONCLUSION OF THE STUDY: Concerns about a spinal CSF leak should not be dismissed in patients suffering from orthostatic headaches when conventional imaging turns out to be normal, even though the yield of identifying a CSF-venous fistula is low.

PMID: 33484155
DOI: 10.1111/head.14048

AUTHORS: Roytman M, Salama G, Robbins MS, Chazen JL.
CITATION: Curr Pain Headache Rep. 2021 Jan 21;25(1):5. doi: 10.1007/s11916-020-00921-4.

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

PMID: 33475890 
DOI: 10.1007/s11916-020-00921-4

AUTHORS: Kim DK, Carr CM, Benson JC, Diehn FE, Lehman VT, Liebo GB, Morris JM, Morris PP, Verdoorn JT, Cutsforth-Gregory JK, Atkinson JD, Brinjikji W.
CITATION: Neurology. 2021 Jan 20:10.1212/WNL.0000000000011522. doi: 10.1212/WNL.0000000000011522. Online ahead of print.

OBJECTIVE OF THE STUDY: Assess the diagnostic yield of lateral decubitus digital subtraction myelography (LDDSM) and stratify LDDSM diagnostic yield by the Bern spontaneous intracranial hypotension (SIH) score of the pre-procedure brain MRI.

STUDY METHODS: This retrospective diagnostic study included consecutive adult patients investigated for SIH who underwent LDDSM. Patients without pre-procedure brain and spine MRI, and patients with extradural fluid collection on spine MRI (type 1 leak) were excluded. LDDSM images and brain MRIs were assessed by two independent blinded readers; a third reader adjudicated any discrepancies. Diagnostic yield of LDDSM was assessed, both overall and stratified by Bern SIH scoring.

RESULTS OF THE STUDY: Of the 62 patients included in this study, 33(53.2%) had a CSF leak identified on LDDSM. Right-sided leaks were more common (70.6%), and the most commonly identified levels of leaks were at T6, T7, and T10. No leak was found in any of the 9 patients with Bern SIH score of 2 or less. Of the 11 patients with Bern SIH score of 3-4, 5(45.5%) had a CSF leak identified, while of the 42 patients with Bern SIH score of 5 or higher, 28 (66.7%) had a CSF leak identified.

CONCLUSIONS OF THE STUDY: LDDSM has a high diagnostic yield for finding the exact location of spinal CSF leak, and the diagnostic yield increases with higher Bern SIH score. No leaks were found in patients with Bern SIH score of 2 or less, suggesting that foregoing invasive testing such as LDDSM in these patients may be appropriate unless accompanied by high clinical suspicion.
Classification of evidence: This study provides Class II evidence that for patients with suspected SIH, higher Bern SIH scores are associated with a greater likelihood of LDDSM-identified CSF leaks.

PMID: 33472917
DOI: 10.1212/WNL.0000000000011522

AUTHORS: Takai K, Taniguchi M.
CITATION: J Neurol. 2021 Jan 3. doi: 10.1007/s00415-020-10319-2. Online ahead of print.

OBJECTIVE OF THE STUDY: Superficial siderosis of the central nervous system is a rare intractable disease induced by chronic subarachnoid hemorrhage. Neurological deficits, such as cerebellar ataxia and hearing difficulties, gradually progress if left undiagnosed. Hemosiderin deposition is irreversible because standard medical treatment has not yet been established. Interventions at the source of bleeding may be the key to a preferable outcome of treatment for chronic subarachnoid hemorrhage; however, the source is not clear in many cases.

STUDY METHODS: Among the consecutive cases diagnosed with a spontaneous cerebrospinal fluid (CSF) leak, cases of superficial siderosis associated with a CSF leak due to a ventral dural defect were retrospectively analyzed.

RESULTS OF THE STUDY: Among 77 cases of a CSF leak, 7 cases (9%) of superficial siderosis were identified (median age of 59 years, male, 4 cases). Defects were diagnosed on 1-mm sliced fast imaging employing steady-state acquisition MRI (n = 5), conventional myelographic CT (n = 1), or dynamic myelographic CT (n = 1) at high thoracic levels (T1-T4). All defects were repaired by direct neurosurgery. During surgery, continuous bleeding from the epidural veins of the internal vertebral venous plexus was identified as the source of subarachnoid hemorrhage. Epidural CSF pulsations through the defect prevented clot formation by the epidural veins. Dural repair stopped free communication between the subarachnoid and epidural spaces, leading to the disappearance of chronic subarachnoid hemorrhage.

CONCLUSION OF THE STUDY: Bleeding from the epidural venous plexus may be the cause of superficial siderosis associated with ventral dural defects. Neurosurgical repair may stop the progression of this condition.

PMID: 33389031
DOI: 10.1007/s00415-020-10319-2