Selective transvenous embolization for dural arteriovenous fistulas with the aid of superselective venograms of fistulous drainages and involved sinuses.

SUMMARY: For the treatment of transvenous embolization (TVE) of dural arteriovenous fistulas (DAVFs) the sites of arteriovenous shunts, fistulous drainage, and the pathological changes inside the affected sinuses were explored in detail by means of preoperative arteriograms, superselective arteriograms, and superselective venograms. Out of 42 adult patients with DAVFs involving a total of 63 sinuses, three distinctive findings were identified as essential for indication of selective TVE for DAVFs. The first is extra-sinus fistulous drainage, which is embolizable fistulous drainage, remote from the major dural sinus, that flows into the sinus lumen. The second is intramural fistulous drainage, which is embolizable fistulous drainage located within the dural leafs of the involved sinus and separate from the major sinus lumen. The third consists of several lumens inside the affected sinuses, which suggests a variety of histological changes in the developmental process of sinus thrombosis and DAVFs. The extra-sinus drainage was occluded in three torcular heroplili fistulas and three transverse sinus fistulas. The intramural fistulous drainage was eliminated in three superior sagittal sinus fistulas. Several lumens inside the affected sinuses were encountered in 17 posterior fossa fistulas (68%) and 10 cavernous sinus fistulas (34%). These distinctive findings were recognized in 52% of the DAVFs. Out of various modalities for treatment of DAVFs, TVE has been the method of choice for the treatment of diffuse DAVFs. The TVE of DAVFs do not correspond to simple sinus occlusion, but imply selective occlusion of fistulous drainages and sinus lumens. The recognition of these three distinctive types of fistulous drainages have clinical impact in that it helps to completely occlude all the fistulous components of fistulas as well as preserve or restore the normal venous outflow through the involved sinus.