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Spontaneous CSF–venous fistulas may be present in up to one-fourth of patients with spontaneous intracranial hypotension. This is a recently discovered type of CSF leak, and much remains unknown about these fistulas. Spinal CSF–venous fistulas are usually seen in coexistence with a spinal meningeal diverticulum, suggesting the presence of an underlying structural dural weakness at the proximal portion of the fistula. The authors now report the presence of soft-tissue venous/venolymphatic malformations associated with spontaneous spinal CSF–venous fistulas in 2 patients with spontaneous intracranial hypotension, suggesting a role for distal venous pathology. In a third patient with spontaneous intracranial hypotension and a venolymphatic malformation, such a CSF–venous fistula is strongly suspected.

Objective: To visualize and treat spinal dural CSF leaks in all patients with intractable spontaneous intracranial hypotension (SIH) who underwent spinal microsurgical exploration. Methods: 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. Results: 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. Conclusion: 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.

BACKGROUND AND PURPOSE:Comprehensive diagnostic criteria encompassing the varied clinical and radiographic manifestations of spontaneous intracranial hypotension are not available. Therefore, we propose a new set of diagnostic criteria. MATERIALS AND METHODS: The diagnostic criteria are based on results of brain and spine imaging, clinical manifestations, results of lumbar puncture, and response to epidural blood patching. The diagnostic criteria include criterion A, the demonstration of extrathecal CSF on spinal imaging. If criterion A is not met, criterion B, which is cranial MR imaging findings of spontaneous intracranial hypotension, follows, with at least one of the following: 1) low opening pressure, 2) spinal meningeal diverticulum, or 3) improvement of symptoms after epidural blood patch. If criteria A and B are not met, there is criterion C, the presence of all of the following or at least 2 of the following if typical orthostatic headaches are present: 1) low opening pressure, 2) spinal meningeal diverticulum, and 3) improvement of symptoms after epidural blood patch. These criteria were applied to a group of 107 consecutive patients evaluated for spontaneous spinal CSF leaks and intracranial hypotension. RESULTS: The diagnosis was confirmed in 94 patients, with use of criterion A in 78 patients, criterion B in 11 patients, and criterion C in 5 patients. CONCLUSIONS:A new diagnostic scheme is presented reflecting the wide spectrum of clinical and radiographic manifestations of spontaneous spinal CSF leaks and intracranial hypotension.

Intracranial hypotension seems to be caused by cerebrospinal fluid (CSF) leakage from a spinal meningeal diverticulum or dura tear. It is characterized by orthostatic headache and diffuse meningeal enhancement on gadolinium-enhanced brain magnetic resonance imaging. Site of CSF leakage could be disclosed with radioisotope cisternography, and computed tomography myelography is useful when cisternography failed to unravel anatomical information. Epidural blood patch is very effective to stop the leakage. We report a case of orthostatic headache caused by intracranial hypotension in a 32-year-old woman. Computed tomography myelography confirmed a CSF leakage in the area of left L2 nerve root. The patient was successfully treated by epidural blood patch. (J Kor Neurotraumatol Soc 2007;3:116-118)