Purpose: The laterocavernous sinus (LCS) is a normal variation of the venous sinus bordered by the dura mater lateral to the cavernous sinus (CS) and one of the major drainage route of the superficial middle cerebral vein (SMCV). In this study, we evaluated the angiographic findings and the procedure and results of transvenous embolization (TVE) in patients with a cavernous sinus dural arteriovenous fistula (CSDAVF) involving the LCS, and discussed technical tips and pit fall in treatment. In 27 patients with a CSDAVF who underwent TVE between January 2007 and October 2015, we evaluated their three-dimensional digital subtraction angiography/digital angiography (3D-DSA/DA) and selective arteriography about the presence or absence of a shunt to the LCS. Subsequently, in patients with a shunt to the LCS, the angiographic findings and the procedure and results of TVE were evaluated.
Results: A shunt to the LCS was observed in four patients (14.8%). In all the four patients, there were multiple shunted pouches of the CS and LCS, and the feeders to the LCS were the artery of the foramen rotundum, middle meningeal artery, and accessory meningeal artery. Reflux to the SMCV and/or uncal vein (UV) via the LCS was present in all the patients. The LCS was connected to the CS at a dorsal site in two patients and at a lateral site in two patients. In all the patients, embolization was performed by advancing a microcatheter to the LCS, but insertion into the LCS was time-consuming in the patients with CS-LCS connection at a dorsal site. The symptoms disappeared without complications in all the patients.
Conclusion: Microcatheter insertion into the LCS is sometimes difficult in patients with CS-LCS connection at a dorsal site, requiring careful attention. In patients with a shunt to the LCS, since embolization of the CS alone can result in Borden type 3 in which cortical venous reflux remains, it is necessary to be careful.