Dural arteriovenous fistulas involving the superior sagittal and parasagittal sinuses: clinical presentation, imaging characteristics and treatment strategies.

BACKGROUND AND PURPOSE: Dural arteriovenous fistulas (DAVFs) involving the superior sagittal (SSS) and parasagittal sinuses are often inappropriately classified. We explore the clinical presentations, imaging characteristics and endovascular treatment strategies these two DAVF subtypes.

MATERIALS AND METHODS: Clinical and imaging data of 19 patients with SSS or parasagittal sinus DAVFs who underwent endovascular treatment in our institution from 2017 and 2022 were retrospectively analyzed. The angiographic findings, endovascular treatment strategies and angiographic outcomes were evaluated and recorded.

RESULTS: Among these 19 patients, 14 had a parasagittal DAVF, 4 had a SSS DAVF, one patient had both a parasagittal and SSS DAVF. Only one (1/19, 5.26%) patient presented with intracranial haemorrhage (ICH); For the parasagittal DAVF group, most of the shunts were located along the middle third of the SSS (12/15, 80%), on the dura in proximity with the junctional zone between the bridging vein and SSS (15/15, 100%), with ipsilateral cortical venous reflux (CVR) (15/15, 100%). For the SSS DAVF group,; all 5 patients had shunting zone along the middle third of the SSS, on the sinus or parasinus wall, with bilateral CVR. Trans-arterial embolization, via the middle meningeal artery (MMA) as the primary route of access, was the primary treatment approach in 95% of cases (19/20). Reflux of embolization material into the SSS was observed in one case (1/5, 20%) of SSS DAVF in which balloon sinus protection was not used during embolization.

CONCLUSIONS: Our study found that parasagittal DAVFs have shunting point(s) centred on the junctional zone of the bridging vein and the SSS with ipsilateral CVR, while SSS DAVFs have shunting point(s) centred on the sinus or parasinus wall with bilateral CVR. Trans-arterial embolization via the MMA(s) can be used as the primary treatment strategy in most cases. Balloon sinus protection during embolization is not necessary in cases of parasagittal DAVF with occluded or stenosed connection with the SSS but its use should be considered in cases of SSS DAVF with patent sinus.

ABBREVIATIONS: DAVF, Dural arteriovenous fistula; SSS, Superior sagittal sinus; CVR, Cortical venous reflux; MMA, middle meningeal artery; ICH, Intracranial haemorrhage; STA, Superficial temporal artery; OA, Occipital artery. CFD, Computational fluid dynamics.