De novo cerebrospinal fluid-venous fistula following multilevel blood and fibrin patching for spontaneous intracranial hypotension.

Treated cerebrospinal fluid-venous fistulas (CVFs) can recur in up to 15% of cases, and they rarely occur at locations remote from the original lesion; the underlying mechanisms remain unclear. We report the case of a male sexagenarian with spontaneous intracranial hypotension (SIH), diffuse spinal nerve root diverticula, and no CVF identified on baseline lateral decubitus CT myelography (CTM). He underwent high-volume epidural and targeted transforaminal blood and fibrin patching with substantial but incomplete symptom relief, followed by transient rebound intracranial hypertension (RIH). Repeat CTM after symptom recurrence demonstrated a new right T5 CVF arising from a remodeled diverticulum and draining into the azygos system. The fistula was successfully treated with transvenous embolization, resulting in sustained clinical and radiological resolution. This case illustrates that in patients with multilevel diverticula, possibly representing connective tissue weakness, post-treatment pressure shifts (including RIH and other causes of episodic cerebrospinal fluid hypertension) may promote the formation or unmasking of CVFs.