Postsurgical Recurrence of CSF-Venous Fistulas in Spontaneous Intracranial Hypotension

PRACTICAL IMPLICATIONS

For patients with continued SIH symptoms or persistent brain MRI findings of SIH after CVF ligation, consider repeat myelographic examination to exclude a recurrent or new CVF.

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 CVFs.⁴ 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 4 cases of SIH in which CVFs have recurred or developed de novo at a different spinal level after complete surgical ligation of the primary lesion. In all cases, the new CVF was not present on any presurgical imaging.

Case Reports

Case 1

A 60-year-old woman developed an orthostatic headache with memory impairment. Neurologic examination revealed right-sided ptosis. Brain MRI showed severe brain sagging and pachymeningeal enhancement confirming SIH. CT myelography (CTM) demonstrated a single CVF in the right T6-T7 neuroforamen (figure 1A), which underwent surgical ligation. SIH symptoms initially improved but then fully recurred by 3 months postoperatively, at which time brain MRI findings were unchanged. A 6-month postoperative CTM showed a new CVF in the right T5-T6 neuroforamen (figure 1B), which was not present on preoperative imaging.

Figure 1. Recurrent CSF-Venous Fistulas (CVF) at Levels Adjacent to the Initial Fistula Ligation.

Case 1: preoperative image A shows initial CVF at the right T6 neuroforamen (arrow), and image B shows postoperative recurrence of CVF at the right T5 neuroforamen (arrow). Case 2: preoperative image C shows initial CVF at the left T10 neuroforamen (arrow), and postoperative image D shows recurrent CVF at the left T9 neuroforamen (arrow).

Case 2

A 67-year-old man presented with an orthostatic, left temporo-occipital headache that had progressed in severity over 4 years. He also suffered disequilibrium with falls, word finding difficulties, slurred speech, and short-term memory impairment. Brain MRI confirmed SIH with severe brain sagging, pachymeningeal enhancement, and venous distension. CTM demonstrated a left T10-T11 CVF (figure 1C), which was surgically ligated. After surgery, the patient reported partial headache improvement with resolution of speech and memory impairments. A 2-month postoperative brain MRI showed partial improvement in pachymeningeal enhancement but with unchanged severe brain sagging. Five months after CVF ligation, he experienced complete recurrence of baseline SIH symptoms, and brain MRI showed worsening severe brain sagging and new small subdural effusions. Over the next 18 months, 4 CTMs failed to show a definite cause for SIH and confirmed successful ligation of the left T10-T11 CVF. A fifth CTM performed 24 months after surgery revealed a new CVF in the left T9-T10 neuroforamen (figure 1D).

Case 3

A 56-year-old woman presented with 4 years of nonpositional suboccipital headaches with progressive memory and concentration difficulties. Neurologic examination was normal. Brain MRI was notable for severe brain sagging, pachymeningeal enhancement, and venous distension confirming SIH. CTM demonstrated a CVF in the left T11-T12 neuroforamen (figure 2A), which was then surgically ligated. After surgery, the patient's symptoms nearly resolved. Recurrence of memory difficulties and a newly orthostatic suboccipital headache developed 4 months postoperatively. A brain MRI 15 months after surgery showed partial improvement in the findings of SIH findings, with improved but persistent brain sag, resolved pachymeningeal enhancement, and unchanged venous distension. A CTM acquired 13 months after the initial surgery confirmed successful ligation of the left T11-T12 CVF, but now showed a new CVF in the right T8-T9 neuroforamen (figure 2B).

Figure 2. Recurrent CSF-Venous Fistulas (CVF) at Sites Distant From the Initial Fistula Ligation.

Case 3: preoperative image A shows initial CVF at the left T11 neuroforamen (arrow), and postoperative image B shows recurrent CVF at the right T8 neuroforamen (arrow). Case 4: preoperative image C shows initial CVF at the left T7 neuroforamen (arrow), and postoperative image D shows recurrent CVF at the left T10 neuroforamen (arrow).

Case 4

A 51-year-old woman with chronic migraine developed a new highly orthostatic, severe occipital headache with right V3 distribution pain and cervicalgia. Neurologic examination was normal. Brain MRI demonstrated severe brain sagging, mild pachymeningeal enhancement, and venous distension consistent with SIH. CTM demonstrated a CVF in the left T7-T8 neuroforamen (figure 2C), which was surgically ligated. After surgery, she experienced 4–6 weeks of significant symptom improvement, followed by return to baseline SIH symptoms. A 2-month postoperative brain MRI showed unchanged findings of SIH. A 10-month postoperative CTM confirmed successful ligation of the left T7-T8 CVF, but revealed a new CVF in the left T10-T11 neuroforamen (figure 2D).

Discussion

In this case series, we report on the development of a newly visible CVF at a location different from the initial causative CVF that was successfully surgically ligated. In each case, the postoperative myelogram confirmed successful surgical ligation of the initial CVF, with new venous enhancement at a location 1–3 spinal segments distant to the operative site reflecting a new CVF. New CVF sites were variably located cranial, caudal, and even contralateral to the site of initial CVF ligation. Potential hypotheses to explain this observation include the possibility that some CVFs may consist of multilevel fistulous connections between the CSF and veins that individuals who develop one CVF may be prone to developing more (e.g., patients with unrecognized connective tissue disorders or preexisting idiopathic intracranial hypertension) and that CVFs may be able recruit new drainage pathways if the underlying fistulous connection is not entirely disrupted. For patients with continued SIH symptoms or persistent brain MRI findings of SIH after CVF ligation, these cases underscore a role for repeat myelographic examination to exclude a recurrent or new CVF.

Appendix. Authors

Study Funding

No targeted funding reported.

Disclosure

The authors report no disclosures relevant to the manuscript. Full disclosure form information provided by the authors is available with the full text of this article at Neurology.org/cp.