Comments 19.5

IPS approach (cases 1-5) In principle, every tributary and every vein or sinus draining the CS can be considered a potential venous approach for transvenous occlusion (TVO) of DCSFs. Among all venous routes, the IPS represents anatomically the shortest, technically the less complicated and clinically the safest approach to the cavernous sinus. If posterior drainage is present, the IPS can frequently be passed without problems either using transfemoral approach or, as frequently used in this study, by percutaneous puncture of the internal jugular * vein. The IPS approach is usually also successful in cases when the IPS is not angiographically identifi able or indeed thrombosed, and allows cross over navigation in the majority of cases10,14,17,21,28. Some authors emphasize the risk of IPS rupture during catheter manipulation, although there are only seven reported cases leading to subarachnoid, intracerebral or epidural hemorrhage, none of which causing a permanent neurological defi cit 9-11,13,19. One patient in our group showed extravasation during IPS catheterization which remained clinically silent. Because the IPS is located in the extradural space, SAH following IPS-rupture is not very likely to occur. As pointed out already by Shiu et al.23, perforating the dura mater in this region requires a certain amount of mechanical force. The use of a 0.035” guide wire for recanalization of a thrombosed IPS (”Kuru-Kuru-technique“)8 can be considered rather aggressive. In such cases the loop technique using small hydrophilic microcatheters and wires (0.010”, 0.012”) is the preferred method, causing less trauma and allowing to successfully manage even so called intractable fi stulas 3 .