Histopathological Analysis of Five Patients with CSF-Venous Fistulas After Surgical Nerve Root Ligation and Resection

ABSTRACT

Cerebrospinal fluid-venous fistulas (CVF) are recognized as the most common cause of spontaneous intracranial hypotension (SIH), however exactly how and why CVFs form remains unclear. To better elucidate CVF pathophysiology, histopathological analysis was performed in five patients with CVFs who underwent operative ligation and removal of the implicated nerve root. There were no archetypal findings seen uniformly in all five cases, and no definitive CSF-venous connections were visualized. However, all cases manifested variable vascular abnormalities. These included dystrophic mineralization in venous walls, focal venous wall thinning, thrombosis, and hemosiderin deposition. Collectively, these findings suggest venous alterations are associated with CVFs, though causality cannot be determined.

ABBREVIATIONS: CVF = cerebrospinal fluid-venous fistula; SIH = spontaneous intracranial hypotension; dCTM = dynamic CT myelography; IHC = immunohistochemistry; SSTR2A = somatostatin receptor 2a; CD31 = cluster of differentiation 31; ERG = ETS-related gene; SMA = smooth muscle actin; IGF-1 = Insulin-like Growth Factor I (IGF-1); TGF-β = Transforming Growth Factor Beta; BMPs = Bone Morphogenic Proteins