Diagnosis of a Cerebrospinal Fluid–Venous Fistula Associated with a Venous Malformation Using Digital Subtraction and Computed Tomography Myelography

Background: Spontaneous cerebrospinal fluid (CSF) leaks can be an intractable cause of orthostatic headaches but have several treatable causes. CSF-venous fistulas are an increasingly recognized cause of rapid CSF leaks. Although CSF-venous fistulas have been previously reported in the literature, their imaging appearance, associated anomalies, and treatment are incompletely understood. We present a case of a CSF-venous fistula draining to adjacent venous malformations with symptoms responding to surgical treatment. This is the first such case to our knowledge showing enhancement of venous malformations on computed tomography myelography. Case Description: A 61-year-old woman with known soft tissue venous malformations presented with progressive hearing loss, headaches, and nausea. Brain magnetic resonance imaging performed at an outside institution showed findings of CSF hypotension. Her symptoms were refractory to a single-level blood patch. Digital subtraction and computed tomography myelography performed at our institution showed CSF-venous fistulas arising from thoracic nerve root sleeve diverticula and draining to paraspinal venous malformations. She was treated with surgical ligation of the fistula and associated nerve roots. At 3-month follow-up, she reported improvement in her headaches, and magnetic resonance imaging showed resolution of all brain abnormalities. Conclusions: CSF-venous fistulas are a relatively uncommon cause of spontaneous CSF leaks. Though difficult to diagnose, they can respond to surgical treatment as seen in this case. In our experience, decubitus digital subtraction myelography combined with computed tomography myelography is instrumental in making the diagnosis and fully characterizing any abnormalities associated with the fistula. This case also supports the suggested association between CSF-venous fistulas and venous malformations, which is worthy of continued study.