Abstracts 2016

This is a collection of selected publication abstracts about spinal CSF leak / intracranial hypotension from 2016.
* Abstract links are included. (click on the PMID number)
* Note that links to full-text are provided for open access papers (line below PMID).

Time-Dependent Changes in Dural Enhancement Associated With Spontaneous Intracranial Hypotension.
Kranz PG, Amrhein TJ, Choudhury KR, Tanpitukpongse TP, Gray L.
AJR Am J Roentgenol. 2016 Dec;207(6):1283-1287. Epub 2016 Aug 24.
The objective of our study was to determine whether the presence of individual imaging signs of spontaneous intracranial hypotension (SIH) is correlated with increasing duration of headache symptoms. Of particular interest is the relationship of symptom duration to dural enhancement because it is the most commonly identified imaging sign in patients with SIH.
Eighty-nine patients with SIH who underwent pretreatment brain MRI and total-spine CT myelography and whose medical record included data on the duration of clinical symptoms were included in this cross-sectional retrospective study. Brain imaging was reviewed for the presence of dural enhancement, brain sagging, and the “venous distention” sign. CT myelograms were assessed for CSF leak. If present, a leak was subcategorized as a high-flow or low-flow leak. Differences in headache duration between subjects with and those without individual imaging signs were compared.
Subjects without dural enhancement on brain MRI had a longer average duration of symptoms than those with dural enhancement present (average symptom duration: 45.3 ± 59.0 [SD] vs 15.1 ± 33.0 weeks, respectively; p = 0.002). No difference in symptom duration was observed between subjects whose MRI studies showed and those whose MRI studies did not show brain sagging (p = 0.10) or the venous distention sign (p = 0.21). The presence of a CSF leak on CT myelography was not associated with symptom duration (p = 0.56) except in the subgroup of patients with low-flow leaks.
Increasing symptom duration in SIH is associated with decreased prevalence of abnormal dural enhancement on brain MRI. Because dural enhancement is considered a hallmark imaging feature of this condition, its absence may exacerbate the problem of underdiagnosis in chronic cases of SIH.
PMID: 27557149
DOI: 10.2214/AJR.16.1638

Vanishing calcification associated with a spontaneous ventral spinal cerebrospinal fluid leak.
Schievink WI, Ross L, Prasad RS, Maya MM.
Cephalalgia. 2016 Dec;36(14):1366-1369. Epub 2016 Jan 20.
2016 Jan 20. pii: 0333102416628468. [Epub ahead of print]
Some patients with spontaneous intracranial hypotension have a ventral spinal cerebrospinal fluid (CSF) leak and these CSF leaks may be associated with calcified disk herniations. Identifying these calcifications is helpful in directing treatment. We report here the unusual case of a patient with a ventral CSF leak in whom the associated calcification absorbed over a five-month period.
A 42-year-old woman developed orthostatic headaches and bilateral abducens nerve palsies. Magnetic resonance imaging of her brain showed typical findings of spontaneous intracranial hypotension. Magnetic resonance imaging of her spine showed an extensive cervicothoracic CSF leak. Computed tomographic myelography showed calcification at the Th1-2 disk space. Three epidural blood patches were performed, but her symptoms persisted. Digital subtraction myelography performed five months later showed an upper thoracic ventral CSF, but the calcification was no longer present. A dural tear, found at surgery at the Th1-2 level, was repaired and the patient made an uneventful recovery.
The resorption of calcifications at the level of a ventral spinal CSF leak could explain the absence of any calcifications in at least some patients with such leaks and demonstrates the usefulness of reviewing previous imaging in patients with ventral CSF leaks if the exact site of the leak remains unknown.
PMID: 26792915

Clinical characteristics of 15 cases of chronic subdural hematomas due to spontaneous intracranial hypotension with spinal cerebrospinal fluid leak.
Wan Y, Xie J, Xie D, Xue Z, Wang Y, Yang S.
Acta Neurol Belg. 2016 Dec;116(4):509-512. Epub 2016 Jan 14.
The etiology of chronic subdural hematoma (CSDH) in patients is diverse. The primary objective of this article was to discuss one of the causes, spontaneous intracranial hypotension with spinal cerebrospinal fluid (CSF) leak, which is usually neglected by the neurosurgeon. All the consecutive 15 patients who underwent operation for CSDHs between June 2012 and June 2014 at Sir Run Run Shaw Hospital of Zhejiang University were included in this retrospective cohort study. The clinical and imaging data of these patients with CSDHs due to spinal CSF leak were retrospectively studied. Fifteen patients, with a mean age of 53.8 ± 8.3 years, underwent operations for CSDH. Hematomas were unilateral in 4 patients and bilateral in 11 patients. Among these patients, eight patients had recurrence of hematomas after operation due to neglect of spinal CSF leak. All patients had fully recovery. Spinal CSF leak is a cause of cSDH, which is overlooked by the doctor.
PMID: 26769700

An Unusual Case of Post-Traumatic Headache Complicated by Intracranial Hypotension.
Siavoshi S, Dougherty C, Ailani J, Yadwadkar K, Berkowitz F.
Brain Sci. 2016 Dec 29;7(1). pii: E3. doi: 10.3390/brainsci7010003.
We present a case of post-traumatic headache complicated by intracranial hypotension resulting in an acquired Chiari malformation and myelopathy with syringomyelia. This constellation of findings suggest a possible series of events that started with a traumatic cerebral spinal fluid (CSF) leak, followed by descent of the cerebellar tonsils and disruption of CSF circulation that caused spinal cord swelling and syrinx. This unusual presentation of post-traumatic headache highlights the varying presentations and the potential sequelae of intracranial hypotension. In addition, the delayed onset of upper motor neuron symptoms along with initially normal head computerized tomography scan (CT) findings, beg the question of whether or not a post-traumatic headache warrants earlier magnetic resonance imaging (MRI).
PMID: 28036062
DOI: 10.3390/brainsci7010003
Full text: mdpi.com/2076-3425/7/1/3/htm

Spontaneous intracranial hypotension with pseudo-subarachnoid hemorrhage.
Yokota H, Yokoyama K, Nakase H.
Acta Neurol Belg. 2016 Dec;116(4):643-644. Epub 2016 Mar 4.
No Abstract.
PMID: 26943460
DOI: 10.1007/s13760-016-0623-4

CSF hypotension: A review of its manifestations, investigation and management.
Pattichis AA, Slee M.
J Clin Neurosci. 2016 Dec;34:39-43. doi: 10.1016/j.jocn.2016.07.002. Epub 2016 Aug 4.
Intracranial cerebrospinal fluid (CSF) hypotension usually arises in the context of known or suspected leak of CSF. This can be spontaneous, or due to central nervous system trauma or dural defects created during lumbar puncture or epidural anaesthesia. Spontaneous intracranial hypotension (SIH) is increasingly being recognised as a cause for orthostatic headache or spontaneous subdural haematoma where no other obvious cause is found. We review CSF physiology, the mechanism of symptom generation in CSF hypotension and the investigation and management of the syndrome. Whilst commonly mild and self-limiting, CSF hypotension may result in life threatening complications and is most often treatable. When the syndrome is severe, prolonged or complicated, epidural blood patching (EBP) is the mainstay of treatment.
PMID: 27499119
DOI: 10.1016/j.jocn.2016.07.002

Epidural Blood Patch for the Treatment of Spontaneous and Iatrogenic Orthostatic Headache.
So Y, Park JM, Lee PM, Kim CL, Lee C, Kim JH.
Pain Physician. 2016 Nov-Dec;19(8):E1115-E1122.
The cerebrospinal fluid (CSF) leakage could be happened spontaneously or related to the procedures such as spinal anesthesia, epidural anesthesia, CSF tapping, intrathecal chemotherapy or other spinal procedures. The leakage of CSF leads to intracranial hypotension of which distinguishing clinical feature is orthostatic headache. The epidural blood patch is a gold-standard treatment for intracranial hypotension-related orthostatic headaches.
We conducted this study to compare the efficacy and number of epidural blood patches for spontaneous and iatrogenic orthostatic headaches.
Retrospective study.
University hospital inpatient and outpatient referred to our pain clinic.
Sex, weight, height, cause of orthostatic headache, leakage site evaluation test, epidural blood patch injection level, number of administered epidural blood patches, and pain intensity data were collected. We classified patients into two groups according to the cause of orthostatic headache: spontaneous (Group S) and iatrogenic (Group I). Patients with myelograms were also divided into 2 groups: multiple cerebrospinal fluid (CSF) leakages and no multiple leakages.
Overall, 133 patients (162 procedures) were managed using epidural blood patches. Groups S and I included 34 and 99 patients, respectively. In Group I, 90.9% of the patients achieved complete recovery following a single procedure, whereas 44.1% of Group S patients required repeated procedures. The average number of administered epidural blood patches was significantly higher in Group S (1.48 ± 0.64) than in Group I (1.11 ± 0.35; P = 0.007). Among 23 patients evaluated via myelography, 12 had multiple CSF leakages. Patients with multiple leakages required a significantly higher number of epidural blood patches, compared to patients without multiple leakages (P = 0.023).
This retrospective study reveals several limitations including insufficient evaluation of CSF leakage site by myelogram and the retrospective nature of the study itself.
Most patients with iatrogenic orthostatic headache required a single epidural blood patch, although most did not undergo a myelogram or similar test. Patients with spontaneous orthostatic headache or multiple CSF leakages were more likely to require a repeated epidural blood patch.
PMID: 27906941
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Spontaneous Intracranial Hypotension: An Etiology for Consciousness Disorder and Coma.
Collange O, Wolff V, Cebula H, Pradignac A, Meyer A, Kindo M, Diemunsch P, Proust F, Mertes PM, Kremer S.
A A Case Rep. 2016 Nov 15;7(10):207-211.
We report 3 cases of spontaneous intracranial hypotension (SIH) associated with consciousness disorder and coma. In patients, SIH was suspected on a computed tomography scan and diagnosed by cerebral magnetic resonance imaging (MRI). Spinal MRI confirmed cerebrospinal fluid leakage. SIH should be seen as an underestimated cause of consciousness disorder and coma, especially in patients with a history of orthostatic headache, spinal injury, or oculomotor signs. Computed tomography scans should be examined for signs of SIH before operating on patients with a spontaneous subdural hematoma. Brain and spine MRI should be performed when SIH is suspected. Our 3 patients have shown good recovery without any neurological sequelae.
PMID: 27552236
DOI: 10.1213/XAA.0000000000000385

CT Fluoroscopy-Guided Blood Patching of Ventral CSF Leaks by Direct Needle Placement in the Ventral Epidural Space Using a Transforaminal Approach.
Amrhein TJ, Befera NT, Gray L, Kranz PG.
AJNR Am J Neuroradiol. October 2016, 37 (10) 1951-1956
Author information
Epidural blood patch treatment of spontaneous intracranial hypotension arising from ventral CSF leaks can be difficult secondary to challenges in achieving ventral spread of patching material. The purpose of this study was to determine the technical success rates and safety profile of direct needle placement into the ventral epidural space via a posterior transforaminal approach.
We retrospectively reviewed consecutive CT fluoroscopy-guided epidural blood patches from June 2013 through July 2015. Cases were included if a posterior transforaminal approach was taken to place the needle directly in the ventral epidural space. Rates of technical success (defined as contrast in the spinal canal ventral epidural space) and optimal epidurogram (defined as contrast spreading into or beyond the middle third of the spinal canal ventral epidural space) were determined. Factors influencing these rates were assessed. All complications, inadvertent intravascular injections, and intrathecal punctures were recorded.
A total of 72 ventral epidural blood patches were identified; immediate technical success was achieved in 95.8% and an optimal epidurogram in 47.2%. Needle position within the spinal canal ventral epidural space was associated with obtaining an optimal epidurogram (P = .005). Inadvertent intravascular injection was identified in 29.3% of cases, but all were venous. There were no inadvertent intrathecal punctures or complications.
Direct needle placement in the ventral epidural space via a transforaminal approach for treatment of ventral CSF leaks has an excellent technical success rate and safety profile. This technique can be considered as a treatment option in selected patients with ventral CSF leaks for whom traditional techniques are unsuccessful.
PMID: 27390315
DOI: 10.3174/ajnr.A4842

Diskogenic microspurs as a major cause of intractable spontaneous intracranial hypotension.
Beck J, Ulrich CT, Fung C, Fichtner J, Seidel K, Fiechter M, Hsieh K, Murek M, Bervini D, Meier N, Mono ML, Mordasini P, Hewer E, Z’Graggen WJ, Gralla J, Raabe A.
Neurology. 2016 Sep 20;87(12):1220-6. doi: 10.1212/WNL.0000000000003122. Epub 2016 Aug 26.
To visualize and treat spinal dural CSF leaks in all patients with intractable spontaneous intracranial hypotension (SIH) who underwent spinal microsurgical exploration.
Patients presenting between February 2013 and July 2015 were included in this consecutive case series. The workup included spinal MRI without and with intrathecal contrast, dynamic myelography, postmyelography CT, and microsurgical exploration.
Of 69 consecutive patients, 15 had intractable symptoms. Systematic imaging revealed a suspicious single location of the leak in these 15 patients. Fourteen patients underwent microsurgical exploration; 1 patient refused surgery. Intraoperatively, including intradural exploration, we identified the cause of the CSF leaks as a longitudinal dural slit (6.1 ± 1.7 mm) on the ventral (10), lateral (3), or dorsal (1) aspect of the dura. In 10 patients (71%), a ventral, calcified microspur originating from the intervertebral disk perforated the dura like a knife. Three patients (22%) had a lateral dural tear with an associated spinal meningeal diverticulum, and in 1 patient (7%), a dorsal osteophyte was causal. The microspurs were removed and the dural slits sutured with immediate cessation of CSF leakage.
The nature of the CSF leak is a circumscribed longitudinal slit at the ventral, lateral, or dorsal dura mater. An extradural pathology, diskogenic microspurs, was the single cause for all ventral CSF leaks. These findings challenge the notion that CSF leaks in SIH are idiopathic or due to a weak dura. Microsurgery is the treatment of choice in cases with intractable SIH.
PMID: 27566748
DOI: 10.1212/WNL.0000000000003122

Epidural Anesthesia Complicated by Subdural Hygromas and a Subdural Hematoma.
Vien C, Marovic P, Ingram B.
Case Rep Anesthesiol. 2016;2016:5789504. Epub 2016 Aug 29.
Inadvertent dural puncture during epidural anesthesia leads to intracranial hypotension, which if left unnoticed can cause life-threatening subdural hematomas or cerebellar tonsillar herniation. The highly variable presentation of intracranial hypotension hinders timely diagnosis and treatment. We present the case of a young laboring adult female, who developed subdural hygromas and a subdural hematoma following unintentional dural puncture during initiation of epidural anesthesia.
PMID: 27651956
DOI: 10.1155/2016/5789504

A classification system of spontaneous spinal CSF leaks.
Schievink WI, Maya MM, Jean-Pierre S, Nuño M, Prasad RS, Moser FG.
Neurology. 2016 Aug 16;87(7):673-9. doi: 10.1212/WNL.0000000000002986. Epub 2016 Jul 20.
Spontaneous spinal CSF leaks cause spontaneous intracranial hypotension but no systematic study of the different types of these CSF leaks has been reported. Based on our experience with spontaneous intracranial hypotension, we propose a classification system of spontaneous spinal CSF leaks.
We reviewed the medical records, radiographic studies, operative notes, and any intraoperative photographs of a group of consecutive patients with spontaneous intracranial hypotension.
The mean age of the 568 patients (373 [65.7%] women) was 45.7 years. Three types of CSF leak could be identified. Type 1 CSF leaks consisted of a dural tear (151 patients [26.6%]) and these were almost exclusively associated with an extradural CSF collection. Type 1a represented ventral CSF leaks (96%) and type 1b posterolateral CSF leaks (4%). Type 2 CSF leaks consisted of meningeal diverticula (240 patients [42.3%]) and were the source of an extradural CSF collection in 53 of these patients (22.1%). Type 2a represented simple diverticula (90.8%) and type 2b complex meningeal diverticula/dural ectasia (9.2%). Type 3 CSF leaks consisted of direct CSF-venous fistulas (14 patients [2.5%]) and these were not associated with extradural CSF collections. A total of 163 patients (28.7%) had an indeterminate type and extradural CSF collections were noted in 84 (51.5%) of these patients.
We identified 3 types of spontaneous spinal CSF leak in this observational study: the dural tear, the meningeal diverticulum, and the CSF-venous fistula. These 3 types and the presence or absence of extradural CSF form the basis of a comprehensive classification system.
PMID: 27440149
DOI: 10.1212/WNL.0000000000002986

Dural Reduction Surgery: A Treatment Option for Frontotemporal Brain Sagging Syndrome
Mostofi E, Schievink WI, Sim VL.
Can J Neurol Sci. 2016 Jul;43(4):593-5. doi: 10.1017/cjn.2016.3. Epub 2016 Mar 14.
Frontotemporal brain sagging syndrome is a dementia associated with hypersomnolence, personality changes, and features of intracranial hypotension on magnetic resonance imaging. The literature is sparse with respect to treatment options; many patients simply worsen. We present a case in which this syndrome responded to lumbar dural reduction surgery. Postoperative magnetic resonance imaging indicated normalization of brain sagging and lumbar intrathecal pressure. Although no evidence of cerebrospinal leak was found, extremely thin dura was noted intraoperatively, suggesting that a thin and incompetent dura could result in this low-pressure syndrome. Clinicians who encounter this syndrome should consider dural reduction surgery as a treatment strategy.
PMID: 26972054

The “Hyperdense Paraspinal Vein” Sign: A Marker of CSF-Venous Fistula
Kranz PG, Amrhein TJ, Schievink WI, Karikari IO, Gray L.
AJNR Am J Neuroradiol. 2016 Jul;37(7):1379-81. doi: 10.3174/ajnr.A4682. Epub 2016 Feb 11.
Author information
CSF-venous fistula is a recently reported cause of spontaneous intracranial hypotension that may occur in the absence of myelographic evidence of CSF leak. Information about this entity is currently very limited, but it is of potential importance given the large percentage of cases of spontaneous intracranial hypotension associated with negative myelography findings. We report 3 additional cases of CSF-venous fistula and describe the “hyperdense paraspinal vein” sign, which may aid in its detection.
PMID: 26869470

Atypical Presentations of Intracranial Hypotension: Comparison with Classic Spontaneous Intracranial Hypotension
Capizzano AA, Lai L, Kim J, Rizzo M, Gray L, Smoot MK, Moritani T.
AJNR Am J Neuroradiol. 2016 Jul;37(7):1256-61. doi: 10.3174/ajnr.A4706. Epub 2016 Mar 3.
Atypical clinical presentations of spontaneous intracranial hypotension include obtundation, memory deficits, dementia with frontotemporal features, parkinsonism, and ataxia. The purpose of this study was to compare clinical and imaging features of spontaneous intracranial hypotension with typical-versus-atypical presentations.
Clinical records and neuroimaging of patients with spontaneous intracranial hypotension from September 2005 to August 2014 were retrospectively evaluated. Patients with classic spontaneous intracranial hypotension (n = 33; mean age, 41.7 ± 14.3 years) were compared with those with intracranial hypotension with atypical clinical presentation (n = 8; mean age, 55.9 ± 14.1 years) and 36 controls (mean age, 41.4 ± 11.2 years).
Patients with atypical spontaneous intracranial hypotension were older than those with classic spontaneous intracranial hypotension (55.9 ± 14.1 years versus 41.7 ± 14.3 years; P = .018). Symptom duration was shorter in classic compared with atypical spontaneous intracranial hypotension (3.78 ± 7.18 months versus 21.93 ± 18.43 months; P = .015). There was no significant difference in dural enhancement, subdural hematomas, or cerebellar tonsil herniation. Patients with atypical spontaneous intracranial hypotension had significantly more elongated anteroposterior midbrain diameter compared with those with classic spontaneous intracranial hypotension (33.6 ± 2.9 mm versus 27.3 ± 2.9 mm; P < .001) and shortened pontomammillary distance (2.8 ± 1 mm versus 5.15 ± 1.5 mm; P < .001). Patients with atypical spontaneous intracranial hypotension were less likely to become symptom-free, regardless of treatment, compared with those with classic spontaneous intracranial hypotension (χ2 = 13.99, P < .001). CONCLUSIONS: In this sample of 8 patients, atypical spontaneous intracranial hypotension was a more chronic syndrome compared with classic spontaneous intracranial hypotension, with more severe brain sagging, lower rates of clinical response, and frequent relapses. Awareness of atypical presentations of spontaneous intracranial hypotension is paramount.
PMID: 26939631

Syringomyelia caused by traumatic intracranial hypotension: a case report and literature review.
Richard S, Humbertjean L, Mione G, Braun M, Schmitt E, Colnat-Coulbois S.
World Neurosurg. 2016 Jul;91:674.e13-8. doi: 10.1016/j.wneu.2016.04.062. Epub 2016 Apr 26.
Syringomyelia due to intracranial hypotension is rarely described. As a consequence, intracranial hypotension is less recognized as a potential cause of syringomyelia or mistaken with Chiari type 1 malformation. The pathogeny is poorly understood and we lack diagnostic and therapeutic strategies for this particular setting.
We describe a 45-year-old patient who developed syringomyelia after about 10 years of undiagnosed intracranial hypotension caused by traumatic C6 cerebrospinal fluid leak. Surgical closing of the leak was required to treat intracranial hypotension after failure of conservative measures and blind epidural patches. It led to a marked improvement of cerebral and spinal signs. We discuss the pathogeny of syringomyelia caused by intracranial hypotension, and highlight a mechanical theory of hyper-pressure against the cervical spine due to blockage of cerebrospinal fluid flow by descent of cerebellar tonsils at the foramen magnum level. We describe discriminating clinical and radiological signs to differentiate intracranial hypotension from Chiari type 1 malformation and discuss mechanisms and causality relating trauma and intracranial hypotension.
Syringomyelia can be a consequence of long-term progression of intracranial hypotension which has to be differentiated from Chiari type 1 malformation. In our case, resolution was achieved by detecting and closing the cerebrospinal fluid leak causing the intracranial hypotension. Reports of similar cases are necessary to understand the origin of cerebrospinal fluid leak in traumatic intracranial hypotension and assess the best therapeutic strategy.
PMID: 27126910

Digital subtraction myelography for the identification of spontaneous spinal CSF-venous fistulas.
Schievink WI, Moser FG, Maya MM, Prasad RS.
J Neurosurg Spine. 2016 Jun;24(6):960-4. doi: 10.3171/2015.10.SPINE15855. Epub 2016 Feb 5.
OBJECTIVE In most patients with spontaneous intracranial hypotension, a spinal CSF leak can be found, but occasionally, no leak can be demonstrated despite extensive spinal imaging. Failure to localize a CSF leak limits treatment options. The authors recently reported the discovery of CSF-venous fistulas in patients with spontaneous intracranial hypotension and now report on the use of digital subtraction myelography in patients with spontaneous intracranial hypotension but no CSF leak identifiable on conventional spinal imaging (i.e., non-digital subtraction myelography).
METHODS The patient population consisted of 53 consecutive patients with spontaneous intracranial hypotension who underwent digital subtraction myelography but in whom no spinal CSF leak (i.e., presence of extradural CSF) was identifiable on conventional spinal imaging.
RESULTS The mean age of the 33 women and 20 men was 53.4 years (range 29-71 years). A CSF-venous fistula was demonstrated in 10 (19%) of the 53 patients. A CSF-venous fistula was found in 9 (27%) of the 33 women and in 1 (5%) of the 20 men (p = 0.0697). One patient was treated successfully with percutaneous injection of fibrin sealant. Nine patients underwent surgery for the fistula. Surgery resulted in complete resolution of symptoms in 8 patients (follow-up 7-25 months), and in 1 patient, symptoms recurred after 4 months.
CONCLUSIONS In this study, the authors found a CSF-venous fistula in approximately one-fifth of the patients with recalcitrant spontaneous intracranial hypotension but no CSF leak identifiable on conventional spinal imaging. The authors suggest that digital subtraction myelography be considered in this patient population.
PMID: 26849709

Spontaneous intracranial hypotension: diagnosis to management.
Limaye K, Samant R, Lee RW.
Acta Neurol Belg. 2016 Jun;116(2):119-25. doi: 10.1007/s13760-015-0577-y. Epub 2015 Dec 10.
Spontaneous Intracranial Hypotension typically occurs from spontaneous CSF leak. CSF volume depletion rather than decrease in CSF pressure is thought to be the main causative feature for intracranial hypotension. More and more cases of intracranial hypotension are getting diagnosed with the advances in the imaging. The advances in the imaging have also led to the better understanding of the dynamic changes that occur with intracranial hypotension. The old theories of CSF overproduction or CSF underproduction have not been substantially associated with intracranial hypotension. It has also led to the fore different atypical clinical features and presentations. Although, it has been known for a long time, the diagnosis is still challenging and dilemma persists over one diagnostic modality over other and the subsequent management. Spontaneous CSF leaks occur at the spinal level and the skull base and other locations are rare. The anatomy of spontaneous intracranial hypotension is a very complex process with significant overlap in connective tissue disorders, previous dural weakness or meningeal diverticula. To localize the location of the CSF leak-CT myelography is the modality of choice. CSF cysternography may provide additional confirmation in uncertain cases and also MRI spine imaging may be of significant help in some cases. Spontaneous intracranial hypotension continues to be a diagnostic dilemma and our effort was to consolidate available information on the clinical features, diagnostics, and management for a practicing neurologist for a “15-20 min quick update of the topic”.
PMID: 26661291

Uncommon Manifestations of Intervertebral Disk Pathologic Conditions.
Diehn FE, Maus TP, Morris JM, Carr CM, Kotsenas AL, Luetmer PH, Lehman VT, Thielen KR, Nassr A, Wald JT.
Radiographics. 2016 May-Jun;36(3):801-23. doi: 10.1148/rg.2016150223. Epub 2016 Apr 15.
Beyond the familiar disk herniations with typical clinical features, intervertebral disk pathologic conditions can have a wide spectrum of imaging and clinical manifestations. The goal of this review is to illustrate and discuss unusual manifestations of intervertebral disk pathologic conditions that radiologists may encounter, including disk herniations in unusual locations, those with atypical imaging features, and those with uncommon pathophysiologic findings. Examples of atypical disk herniations presented include dorsal epidural, intradural, symptomatic thoracic (including giant calcified), extreme lateral (retroperitoneal), fluorine 18 fluorodeoxyglucose-avid, acute intravertebral (Schmorl node), and massive lumbar disk herniations. Examples of atypical pathophysiologic conditions covered are discal cysts, fibrocartilaginous emboli to the spinal cord, tiny calcified disks or disk-level spiculated osteophytes causing spinal cerebrospinal fluid (CSF) leak and intracranial hypotension, and pediatric acute calcific discitis. This broad gamut of disease includes a variety of sizes of disk pathologic conditions, from the tiny (eg, the minuscule calcified disks causing high-flow CSF leaks) to the extremely large (eg, giant calcified thoracic intradural disk herniations causing myelopathy). A spectrum of clinical acuity is represented, from hyperacute fibrocartilaginous emboli causing spinal cord infarct, to acute Schmorl nodes, to chronic intradural herniations. The entities included are characterized by a range of clinical courses, from the typically devastating cord infarct caused by fibrocartilaginous emboli, to the usually spontaneously resolving pediatric acute calcific discitis. Several conditions have important differential diagnostic considerations, and others have relatively diagnostic imaging findings. The pathophysiologic findings are well understood for some of these entities and poorly defined for others. Radiologists’ knowledge of this broad scope of unusual disk disease is critical for accurate radiologic diagnoses. Online supplemental material is available for this article.
PMID: 27082664

Diffuse non-aneurysmal SAH in spontaneous intracranial hypotension: Sequela of ventral CSF leak?
Schievink WI, Maya MM.
Cephalalgia. 2016 May;36(6):589-92. doi: 10.1177/0333102415604473. Epub 2015 Sep 7.
Spontaneous intracranial hypotension due to a spinal cerebrospinal fluid (CSF) leak has become a well-recognized cause of headaches. Recently, various unusual neurological syndromes have been described in such patients with chronic ventral CSF leaks, including superficial siderosis and an amyotrophic lateral sclerosis-like syndrome. The authors now report two patients with spontaneous intracranial hypotension due to a chronic ventral CSF leak who suffered a diffuse non-aneurysmal subarachnoid hemorrhage (SAH).
A 62-year-old woman underwent uneventful microsurgical repair of a ventral thoracic CSF leak that had been present for 13 years. Seventeen months after surgery, she was found unresponsive and CT showed a diffuse intracranial SAH. Cerebral angiography and spine and brain MRI did not reveal a source of the SAH. A 73-year-old woman was found unresponsive and CT showed a diffuse intracranial SAH. Cerebral angiography and brain MRI did not reveal a source of the SAH, although superficial siderosis was detected. Spine MRI showed a ventral thoracic CSF leak that by history had been present for 41 years. She underwent uneventful microsurgical repair of the CSF leak.
The authors suggest that patients with a ventral spinal CSF leak of long duration may be at risk of diffuse non-aneurysmal SAH.
PMID: 26346560

Transpedicular surgical approach for the management of thoracic osteophyte-induced intracranial hypotension refractory to non-operative modalities: case report and review of literature.
Dash D, Jalali A, Harsh V, Omeis I.
Eur Spine J. 2016 May;25 Suppl 1:209-15. doi: 10.1007/s00586-016-4408-5. Epub 2016 Jan 29.
In this article, we aim to describe the presentation and management of a case of spontaneous intracranial hypotension caused by a dural tear from a ventral thoracic osteophyte at the T12 level that was refractory to non-surgical treatment modalities. A review of the literature has been performed. Also a proposal of diagnostic and treatment algorithm is presented. Intracranial hypotension and CSF leak as a result of dural tear is a common phenomenon. However, the detection of the source of CSF leak from a thoracic spinal osteophyte has rarely been reported.
Diagnostic workup including MRI and CT Myelogram as well as application of epidural blood patches and surgical technique of hemilaminectomy and osteophytectomy by transpedicular approach have been described. Literature review was conducted using relevant search terms in PubMed.
The patient’s spontaneous intracranial hypotension symptoms resolved and this persisted on follow up visits. Review our experience as well as similar cases in the literature pointed us towards a diagnostic and treatment algorithm.
Spontaneous resolution is the norm for intracranial hypotension of most etiologies and management of all such cases begins with fluid resuscitation coupled with bed rest. On failure of conservative therapy, autologous epidural blood patches into the spinal epidural space should be tried, which often produce an immediate relief of symptoms. Osteophyte-induced dural tear and consequent intracranial hypotension may require surgical intervention if the symptoms are refractory to conservative treatment. Under all circumstances a careful step-wise approach for diagnosis and treatment of spontaneous intracranial hypotension needs to be followed, as we have proposed in our article.
PMID: 26831535

Prominent Inferior Intercavernous Sinus on Sagittal T1-Weighted Images: A Sign of Intracranial Hypotension.
Alcaide-Leon P, López-Rueda A, Coblentz A, Kucharczyk W, Bharatha A, de Tilly LN.
AJR Am J Roentgenol. 2016 Apr;206(4):817-22. doi: 10.2214/AJR.15.14872. Epub 2016 Feb 25.
The purpose of this study is to describe the diagnostic accuracy of the dilatation of the inferior intercavernous sinus as a sign of intracranial hypotension and to raise awareness of this anatomic structure, which can be mistaken for a focal pituitary lesion.
Sagittal T1-weighted images of 26 patients with intracranial hypotension and 28 control subjects were evaluated to determine the presence of a distended inferior intercavernous sinus. Information about the shape, size, and signal of the inferior intercavernous sinus was also collected. The chi-square test was used to compare both groups. Sensitivity and specificity of the dilatation of the inferior intercavernous sinus as a sign of intracranial hypotension were calculated.
A visible inferior intercavernous sinus was found in 13 of 26 patients with intracranial hypotension (50%) and in four of 28 control subjects (14.3%). These percentages were significantly different (p = 0.005). There was no significant difference in size of the inferior intercavernous sinus in the intracranial hypotension group (median, 5.86 mm(2); interquartile range, 6.28 mm(2)) compared with the control group (median, 8.25 mm(2); interquartile range, 16.69 mm(2)). Changes in the size of the inferior intercavernous sinus were detected in congruence with the appearance or resolution of intracranial hypotension.
Dilatation of the inferior intercavernous sinus is frequently associated with intracranial hypotension, although it can also be found in the healthy adult as a normal anatomic variant. Recognition of this anatomic structure is important to avoid mistaking it for a focal pituitary lesion.
PMID: 27003051

The Relief of Unilateral Painful Thoracic Radiculopathy without Headache from Remote Spontaneous Spinal Cerebrospinal Fluid Leak.
Son BC, Ha SW, Lee SH, Choi JG.
Pain Res Manag. 2016;2016:4798465. doi: 10.1155/2016/4798465. Epub 2016 Apr 17.
Spontaneous intracranial hypotension (SIH) caused by spontaneous spinal cerebrospinal fluid (CSF) leaks produces orthostatic headaches. Although upper arm pain or paresthesia is reportedly associated with SIH from spontaneous spinal CSF leak in the presence of orthostatic headache, low thoracic radicular pain due to spontaneous spinal CSF leak unassociated with postural headache is extremely rare. We report a 67-year-old female who presented with chronic, positional radicular right T11 pain. Computed tomography myelography showed a spontaneous lumbar spinal CSF leak at L2-3 and repeated lumbar epidural blood patches significantly alleviated chronic, positional, and lower thoracic radiculopathic pain. The authors speculate that a chronic spontaneous spinal CSF leak not severe enough to cause typical orthostatic headache or epidural CSF collection may cause local symptoms such as irritation of a remote nerve root. There might be considerable variabilities in the clinical features of SIH which can present a diagnostic challenge.
PMID: 27445613
PMCID: PMC4904640
DOI: 10.1155/2016/4798465

Intraspinal hemorrhage in spontaneous intracranial hypotension: link to superficial siderosis? Report of 2 cases
Schievink WI, Wasserstein P, Maya MM.
J Neurosurg Spine. 2016 Mar;24(3):454-6. doi: 10.3171/2015.6.SPINE15428. Epub 2015 Nov 20.
Spontaneous intracranial hypotension due to a spinal CSF leak has become a well-recognized cause of headaches, but such spinal CSF leaks also are found in approximately half of patients with superficial siderosis of the CNS. It has been hypothesized that friable vessels at the site of the spinal CSF leak are the likely source of chronic bleeding in these patients, but such an intraspinal hemorrhage has never been visualized. The authors report on 2 patients with spontaneous intracranial hypotension and intraspinal hemorrhage, offering support for this hypothesis. A 33-year-old man and a 62-year-old woman with spontaneous intracranial hypotension were found to have a hemorrhage within the ventral spinal CSF collection and within the thecal sac, respectively. Treatment consisted of microsurgical repair of a ventral dural tear in the first patient and epidural blood patching in the second patient. The authors suggest that spontaneous intracranial hypotension should be included in the differential diagnosis of spontaneous intraspinal hemorrhage, and that the intraspinal hemorrhage can account for the finding of superficial siderosis when the CSF leak remains untreated.
PMID: 26588500

Reversible coma and Duret hemorrhage after intracranial hypotension from remote lumbar spine surgery: case report.
Bonow RH, Bales JW, Morton RP, Levitt MR, Zhang F
J Neurosurg Spine. 2016 Mar;24(3):389-93. doi: 10.3171/2015.6.SPINE1521. Epub 2015 Nov 20.
Intracranial hypotension is a rare condition caused by spontaneous or iatrogenic CSF leaks that alter normal CSF dynamics. Symptoms range from mild headaches to transtentorial herniation, coma, and death. Duret hemorrhages have been reported to occur in some patients with this condition and are traditionally believed to be associated with a poor neurological outcome. A 73-year-old man with a remote history of spinal fusion presented with syncope and was found to have small subdural hematomas on head CT studies. He was managed nonoperatively and discharged with a Glasgow Coma Scale score of 15, only to return 3 days later with obtundation, fixed downward gaze, anisocoria, and absent cranial nerve reflexes. A CT scan showed Duret hemorrhages and subtle enlargement of the subdural hematomas, though the hematomas remained too small to account for his poor clinical condition. Magnetic resonance imaging of the spine revealed a large lumbar pseudomeningocele in the area of prior fusion. His condition dramatically improved when he was placed in the Trendelenburg position and underwent repair of the pseudomeningocele. He was kept flat for 7 days and was ultimately discharged in good condition. On long-term follow-up, his only identifiable deficit was diplopia due to an internuclear ophthalmoplegia. Intracranial hypotension is a rare condition that can cause profound morbidity, including tonsillar herniation and brainstem hemorrhage. With proper identification and treatment of the CSF leak, patients can make functional recoveries.
PMID: 26588496

Treatment and prognosis of subdural hematoma in patients with spontaneous intracranial hypotension
Chen YC, Wang YF, Li JY, Chen SP, Lirng JF, Hseu SS, Tung H, Chen PL, Wang SJ, Fuh JL.
Cephalalgia. 2016 Mar;36(3):225-31. doi: 10.1177/0333102415585095. Epub 2015 May 5.
The objective of this article is to elucidate the outcome, prognostic predictors and timing of surgical intervention for subdural hematoma (SDH) in patients with spontaneous intracranial hypotension (SIH).
Patients with SDH were identified retrospectively from 227 consecutive SIH patients. Data were collected on demographics, clinical courses, neuroimaging findings, and treatment of SDH, which was later divided into conservative treatment, epidural blood patches (EBP), and surgical intervention. Poor outcome was defined as severe neurological sequelae or death.
Forty-five patients (20%) with SDH (mean maximal thickness 11.9 ± 6.2 mm) were recruited. All 15 patients with SDH <10 mm achieved good outcomes by either conservative treatment or EBP. Of 30 patients with SDH ≥10 mm, patients with uncal herniation (n = 3) had poor outcomes, even after emergent surgical evacuation (n = 2), compared to those without (n = 27) (100% vs. 0%, p < 0.001). Fourteen patients underwent surgical evacuation, resulting in good outcomes in all 12 who received early intervention and poor outcomes in the remaining two who received delayed intervention after Glasgow Coma Scale (GCS) score ≤8 (100% vs. 0%, p = 0.01). CONCLUSIONS: Uncal herniation results in poor outcomes in patients with SIH complicated with SDH. In individuals with SDH ≥10 mm and decreased GCS scores, early surgical evacuation might prevent uncal herniation. PMID: 25944817

Spontaneous Intracranial Hypotension Associated with Kinetic Tremor and Ataxia.
Salazar R1.
Tremor Other Hyperkinet Mov (N Y). 2016 Mar 9;6:366. doi: 10.7916/D8HQ3ZN5. eCollection 2016.
Spontaneous intracranial hypotension (SIH) is a clinically variable syndrome caused by low cerebrospinal fluid (CSF) pressure due to a non-traumatic CSF leak.
This case describes a 68-year-old gentleman who presents with chronic and slightly progressive kinetic tremor of bilateral hands associated with gait ataxia and gait start hesitation.
This case underscores the importance of having a high index of suspicion for the diagnosis of SIH when encountering a patient presenting with late-onset progressive kinetic tremor and gait ataxia syndrome.
PMID: 27351232
PMCID: PMC4790469
DOI: 10.7916/D8HQ3ZN5

Efficacy of epidural blood patch with fibrin glue additive in refractory headache due to intracranial hypotension: preliminary report.
Elwood J, Dewan M, Smith J, Mokri B, Mauck W, Eldrige J.
Springerplus. 2016 Mar 11;5:317. doi: 10.1186/s40064-016-1975-1. eCollection 2016.
Injection of fibrin glue mixed with blood into the epidural space to reliably and effectively treat medically refractory orthostatic headache caused by spinal cerebrospinal fluid (CSF) leaks and subsequent intracranial hypotension has recently been described. The study described in this article utilizes an analogous technique to gauge the therapeutic reproducibility of this novel technique.
Eight patients with medically refractory headache resulting from intracranial hypotension caused by spinal CSF leaks received epidural injections of combined fibrin glue, autologous blood, and Isovue contrast at the L1-2 vertebral level using intermittent fluoroscopic guidance. Pre-procedure, 1-week post-procedure, and 3-month post-procedure headache pain scores were collected and used for comparison.
Three out of 8 patients reported relief at 1 week, although 1 of these 3 patients had returned to their baseline pain intensity at 3 months. Four patients reported no change at 1 week, though 2 of these patients had reduction of their chronic headache pain at 3 months. A single patient reported increased pain 1 week after the procedure, which persisted at 12 weeks. Overall, 4 out of the 8 patients had decreased pain scores at 3-month follow-up.
We did not achieve a similar frequency of headache resolution as reported in prior original studies. However, a subset of patients did appear to receive substantial benefit from the combined fibrin glue-blood patching procedure. This technique may prove to be useful in medically refractory cases, including those patients who continue to have symptoms despite the prior administration of conventional epidural blood patches.
PMID: 27066348
Full text

Venous infarction mimicking a neoplasm in spontaneous intracranial hypotension: an unusual cause of Parinaud’s syndrome.
Bray TJ, Chandrashekar H, Rees J, Burke A, Merve A, Thust S.
J Surg Case Rep. 2016 Mar 17;2016(3). pii: rjw037. doi: 10.1093/jscr/rjw037.
We present a case of longstanding, undiagnosed spontaneous intracranial hypotension (SIH) with an acute presentation of Parinaud’s syndrome, in whom serial imaging demonstrated development of a midbrain mass. The patient was ultimately diagnosed with tumefactive venous infarction secondary to SIH. However, this patient underwent a brainstem biopsy, which in retrospect may have been avoidable. This case demonstrates the imaging features of tumefactive venous infarction in SIH and highlights the risk of misinterpretation as a neoplasm with potentially catastrophic consequences.
PMID: 26987945
Full text: PMC4794942

Chronic Subdural Hematoma Associated with Spontaneous Intracranial Hypotension: Therapeutic Strategies and Outcomes of 55 Cases.
Takahashi K, Mima T, Akiba Y.
Neurol Med Chir (Tokyo). 2016;56(2):69-76. doi: 10.2176/nmc.oa.2015-0032. Epub 2015 Oct 21.
Spontaneous intracranial hypotension (SIH) has increasingly been recognized, and it is well known that SIH is sometimes complicated by chronic subdural hematoma (SDH). In this study, 55 cases of SIH with SDH were retrospectively analyzed, focusing on therapeutic strategies and outcomes. Of 169 SIH cases (75 males, 84 females), 55 (36 males, 19 females) were complicated by SDH. SIH was diagnosed based on clinical symptoms, neuroimaging, and/or low cerebrospinal fluid pressure. Presence of orthostatic headache and diffuse meningeal enhancement on magnetic resonance imaging were regarded as the most important criteria. Among 55 SIH with SDH cases, 13 improved with conservative treatment, 25 initially received an epidural blood patch (EBP), and 17 initially underwent irrigation of the hematomas. Of the 25 initially treated with EBP, 7 (28.0%) needed SDH surgery and 18 (72.0%) recovered fully without surgery. Of 17 SDH cases initially treated with surgery, 6 (35.7%) required no EBP therapy and the other 11 (64.3%) needed EBP and/or additional SDH operations. In the latter group, 2 cases had transient severe complications during and after the procedures. One of these 2 cases developed a hoarse voice complication. Despite this single, non-severe complication, all enrolled in this study achieved good outcomes. The present study suggests that patients initially receiving SDH surgery may need additional treatments and may occasionally have complications. If conservative treatment is insufficient, EBP should be performed prior to hematoma irrigation.
PMID: 26489406

Headache Rounds: Sudden Onset Chronic Daily Headache
Wrobel Goldberg S, Young W.
Headache. 2016 Feb;56(2):379-88. doi: 10.1111/head.12724. Epub 2015 Dec 6.
The following article is a Thomas Jefferson Headache Center headache rounds presentation. A 37-year-old woman, who reports a history of chronic sinusitis, developed sudden onset headache 1 1/2 years prior to her initial presentation at the Jefferson Headache Center. At that time she noted acute severe pressure-like pain bilaterally in her neck, which radiated to her forehead above her eyebrows. She denied fever, rashes, or nasal discharge at the time. The pain was much more intense than her usual “sinus headaches” and associated with a positional component, occurring only upon standing, reaching a peak intensity of 10/10 that would only last seconds and remaining as a dull milder continuous frontal pain for up to 12 hours. She had nausea and vomiting but no photophobia, phonophobia, or osmophobia. There was no rhinorrhea, conjuctival injection, or eye tearing. The pain was alleviated upon lying down. After several emergency department visits, a head computed tomography was performed revealing chronic sinus disease that led her to sinus surgery with no improvement of symptoms. For several months, she was unsuccessfully treated with preventive therapy including topiramate, duloxetine, gabapentin, onabotulinumtoxin A, and abortive therapy including triptans, nonsteroidal anti-inflammatory drugs, barbiturates, and muscle relaxants. Acupuncture and occipital nerve blocks provided limited relief. The patient denied a prior medical and family history of migraines. Since the onset of symptoms, the patient continued to have intermittent explosive frontal headaches that would be triggered by standing and improved upon lying down. As time elapsed, she also noticed suboccipital pain and neck discomfort worsened by Valsalva maneuvers such as straining and coughing. She also reported bilateral upper extremity paresthesias along with subjective weakness.
PMID: 26638182

Treatment strategy for cerebral hypotension caused by spontaneous cerebrospinal fluid leaks.
Janssen I, Gempt J, Gerhardt J, Meyer B, Ryang YM.
Acta Neurochir (Wien). 2016 Feb;158(2):273-8. doi: 10.1007/s00701-015-2653-8. Epub 2015 Dec 5.
Spontaneous spinal cerebrospinal fluid (CSF) leaks are rare (5 per 100,000 per year). Treatment generally consists of conservative therapy or interventional therapy with epidural blood patching. Surgical treatment is conducted rarely, usually in cases when conservative or interventional treatment has failed. The aim of our case series was to assess the clinical outcome after surgery.
Our clinical database was reviewed for patients with spontaneous spinal CSF leaks who underwent surgical exploration between 2010 and 2013. Etiology, symptoms, preoperative imaging, type of required surgical method, intraoperative findings, and clinical outcome were reported.
We identified five patients with a mean age of 62 years with spontaneous spinal CSF leaks who were treated surgically. Two patients received surgery after failure of interventional treatment. The origin of the CSF leak could be identified intraoperatively in three cases. Surgical technique in all cases consisted of an interlaminar fenestration or hemilaminectomy and a complete foraminotomy to explore the thecal sack and the exiting nerve roots and identify the CSF leak. After surgery, the preoperative symptoms improved in all patients. In one case, there was a relapse after 4 weeks.
Preoperative identification of a CSF leak with MRI was positive in only one case. In all other cases, a post-myelography CT had to be performed. In all cases, the preoperative symptoms improved after surgery. Surgical treatment is an effective treatment of spontaneous cerebrospinal fluid leaks in cases of refractory symptoms after failed conservative or interventional treatment.
PMID: 26638152

Reversible alterations of the neuronal activity in spontaneous intracranial hypotension
Amemiya S, Takahashi K, Mima T, Yoshioka N, Miki S, Ohtomo K.
Cephalalgia. 2016 Feb;36(2):162-71. doi: 10.1177/0333102415585085. Epub 2015 May 1.
The aim of this article is to investigate the pathophysiology underlying the alternation of the cognitive function and neuronal activity in spontaneous intracranial hypotension (SIH).
Fifteen patients with SIH underwent resting-state functional magnetic resonance imaging and working-memory (WM) test one day before and one month after a surgical operation. Alternation of the cognitive function and spontaneous neuronal activity measured as amplitude of the low-frequency fluctuations (ALFF) and the functional connectivity of the default-mode network (DMN) and frontoparietal networks (FPNs) were evaluated.
WM performance significantly improved post-operatively. Whole-brain linear regression analysis of the ALFF revealed a positive correlation between cognitive performance change and ALFF change in the precuneus while a negative correlation was found in the bilateral orbitofrontal cortices (OFCs) and right medial frontal cortex (MFC). The ALFF changes normalised with the WM performance improvement post-operatively. The FPN activity in the right OFC was also increased pre-operatively. Partial correlation analysis revealed a significant correlation between WM performance and right OFC activity controlled for right FPN activity.
The abnormal activity of the OFCs and MFC that is not originating from the synchronous intrinsic network activity, together with the decreased activity of the central node of the DMN, could lead to cognitive impairment in SIH that is reversible through restoration of the cerebrospinal fluid.
PMID: 25934316

The utility of radioisotope cisternography in low CSF/volume syndromes compared to myelography.
Monteith TS, Kralik SF, Dillon WP, Hawkins RA, Goadsby PJ.
Cephalalgia. 2016 Jan 27. pii: 0333102416628467. [Epub ahead of print]
The objective of this report is to compare computed tomography (CT) and magnetic resonance (MR) myelography with radioisotope cisternography (RC) for detection of spinal cerebrospinal (CSF) leaks.
We retrospectively reviewed 12 spontaneous intracranial hypotension (SIH) patients; CT and RC were performed simultaneously. Three patients had MR myelography.
CT and/or MR myelography identified CSF leaks in four of 12 patients. RC detected spinal leaks in all three patients confirmed by CT myelography; RC identified the CSF leak location in two of three cases, and these were due to osteophytic spicules and/or discs. RC showed only enlarged perineural activity. Only intrathecal gadolinium MR myelography clearly identified a slow leak from a perineural cyst. In eight remaining cases, the leak site was unknown; however, two of these showed indirect signs of CSF leak on RC. CSF slow leaks from perineural cysts were the most common presumed etiology; and the cysts were best visualized on myelography.
RC is comparable to CT myelography but has spatial limitations and should be limited to atypical cases.
PMID: 26823556

Myelographic Techniques for the Detection of Spinal CSF Leaks in Spontaneous Intracranial Hypotension.
Kranz PG, Luetmer PH, Diehn FE, Amrhein TJ, Tanpitukpongse TP, Gray L.
AJR Am J Roentgenol. 2016 Jan;206(1):8-19. doi: 10.2214/AJR.15.14884.
Spinal leakage of CSF causes almost all cases of spontaneous intracranial hypotension. Leak detection and localization are important for both diagnosis and treatment. The myelographic appearance of the leaks may vary, however, depending on the cause of the leak, rate of leakage, and imaging modality used.
The purpose of this article is to review the imaging of spinal CSF leaks and to assist in the selection of appropriate imaging modalities in this condition.
PMID: 26700332