Characteristic of Non–Sinus-Type Parasagittal Dural Arteriovenous Fistulas: Clinical and Cadaveric Experiences

Abstract

BACKGROUND: In parasagittal dural arteriovenous fistulas (DAVFs), the shunt point is on the falx cerebri and drains directly into the cortical vein. The venous structure anatomy of the falx cerebri is not well understood. OBJECTIVE: To describe a parasagittal DAVF as a non–sinus-type DAVF using clinical expertise and cadaver analysis. We focused on the clinical characteristics of parasagittal DAVFs, anatomy of the cortical vein directly flowing into the falx cerebri, and venous route in the falx cerebri. METHODS: Six patients with parasagittal DAVFs were examined between April 2009 and March 2019. In 7 cadaver heads, we examined the entire falx cerebri length and the cortical veins flowing into it were noted. The falx cerebri was divided down from the midline into the dura propria to examine the venous pattern. RESULTS: Clinically, all 6 cases were classified as parasagittal DAVFs. Intracerebral hemorrhage occurred in 2 patients (33.3%). In all 6 cases, only the cortical vein was the draining vein ipsilateral to the shunt point. One patient (16.7%) underwent transarterial embolization, 2 (33.3%) underwent direct surgery, and 2 (33.3%) underwent combined transarterial embolization with direct surgery. In the anatomic study, 7 (50.0%) venous structures directly flowed into the falx cerebri and 5 (35.7%) were located in the parasinus portion. The veins directly flowing into the falx ran through the dura propria on each side. CONCLUSION: Based on the clinical characteristics and anatomic features, clinicians must pay attention to cerebral hemorrhage in patients with parasagittal DAVFs to manage aggressive symptoms.