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Spinal Findings in Spontaneous Intracranial Hypotension 2006

General Spine

Jocelyn H Medina, M.D., Non ASSR Member
Stephen Falcone, M.D., ASSR Member
Kevin Abrams, M.D., ASSR Member

Excerpta Extraordinaire

Excerpta

Spontaneous intracranial hypotension (SIH) is a syndrome of postural headaches arising spontaneously, without prior lumbar puncture. It is a benign condition that is difficult to diagnose because of its highly variable and often nonspecific clinical and imaging presentation (1, 2, 3). It is thought to be caused by development of cerebrospinal fluid (CSF) leaks usually in the spine (4). Spinal imaging may be necessary in order to identify the site of the CSF leakage, particularly in refractory or diagnostically difficult cases or when a surgical or invasive approach is planned(5). This study retrospectively reviews the spinal findings of eleven patients with SIH in order to further characterize the spinal findings in the disease.

Purpose

The role of spinal imaging in diagnosis and management of SIH has not been well established. Multiple spinal findings have been reported in SIH, but the sensitivity and specificity of these findings has not been well characterized in the current literature (6,7). The first major goal of our study is to better characterize spinal findings and determine which findings are clinically useful. A second goal of our research is to define when spinal imaging is necessary in SIH and demonstrate that in the appropriate clinical setting, spinal imaging is a useful and beneficial tool in the diagnosis and management of the disease.

Methods & Materials

Eleven (4 male, and 7 female) patients ages 25-56years old with the clinical diagnosis of Spontaneous Intracranial Hypotension were identified at University of Miami/Jackson Memorial Hospital, and Baptist Memorial Hospital. Clinical records and operative reports were reviewed where applicable. All cranial MRI, spinal MRI, and CT myelograms were collected for each patient and retrospectively reviewed by 2 attending neuroradiologists. Four of the patients had complete imaging workup to include cranial and spinal MRI, and CT myelography of the entire spine. Three patients had MRI imaging of the brain and spine, but no myelogram. Three patients had spinal MRI imaging only and one patient had a CT myelogram of the entire spine and MRI of the brain and upper cervical spine.

Results

Fluid collections were the most common imaging finding and were seen in 10 of 11 patients (91%). A thickened epidural venous plexus was another common imaging finding seen in 9 patients (82%). Dural enhancement was seen in 64%. Four patients (36%) had evidence of a high signal between the spinous processes of C1 and C2, or the false c1/2 localizing sign describe previously by Shievink (8). 27% (3 patients) had nerve root cysts, and 3 (27%) patients had dilated epidural veins. In the 5 patients who underwent CT myelography, 4 patients (36%) had active extravasation of contrast.

Four patients had surgical correlation. Three of these had complete concordance with imaging and surgical findings. The patient with discordant surgical and imaging findings was felt to have a leak by CT myelography extending into the region of the brachial plexus. At surgery, no active extravasation of CSF was seen at the site. However, the site was surgically packed and the patients clinical symptoms subsequently resolved.

Conclusion

An array of imaging findings were identified in this series of patients with SIH. All the patients in the series had at least two of findings in the spine defined by this study even in the absence of classic intracranial imaging findings. Notably, most of the patients in this series demonstrated spinal fluid collections, dural enhancement and a thickened epidural venous plexus, suggesting that these may represent sensitive findings for the disease. The use of contrast was also noted to be extremely helpful in distinguishing thickened venous plexus from fluid collections.

References

1. Schaltenbrand G (1938). Neuere Anschauungen zur Pathophysiologie der Liquorzirkulation. Zeentralbl Neurochir 3: 290-300.
2. Jacobs MB, Wasserstein PH (1991) Spontaneous intracreanial hypotension: An uncommon and underrecognized cause of headache. West J Med 155: 178-180
3. Messori A, Salvolini U (2002). Comment on Chiappariniet al.: spinal radiological findings in nine patients with spontaneous intracranial hypotension. Neuroradiology 44: 151-152.
4. Schievink WI, Meyer FB, Atkinson JLD, Mokri B (1996) Spontaneious spinal cerebrospinal fluid leaks and intracranial hypotension. J Neurosurg 84: 598-605.
5. Spelle, L, Boulin A, Tainturier C, Visot A, Graveleau P, Pierot L (2001) Neuroimaging features of spontaneous intracranial hypotension. Neuroradiology 43: 622-627.
6. Messori A, Polonara G, Salvolini U (2001) Dilation of Cervical Epidural veins in intracranial hypotension. AJNR 22: 224-225.
7. Chiaparini L, Farina L, D'Incerti, Erbetta A, Pareyson, Carriero R, Savoiardo M (2002). Spinal radiological findings in nine patients with spontaneous intracreanial hypotension. Neuroradiology 44: 143-150.
8. Schievink WI, Maya MM, Tourje J (2004). False localizing sign of C1/2 cerebrospinal fluid leak in spontaneous intracranial hypotension. J Neurosurg 100:639-644.