[Extra-intracranial shunts by venous grafts interposed on the carotid system]

Patients with occlusive arterial diseases, tumors invading the vascular structures of the skull base or giant aneurysms may benefit from an EICB. Most of the time this can be achieved using a scalp artery. But in cases of a thrombotic ECA, excessively short or thin scalp branches or destruction of those by prior cranial surgery, an interposed venous graft is needed. In the author's series, which consists of 16 patients, the bypass was performed for ICA occlusive diseases in 5, before complete removal of cavernous sinus tumours in 4 and prior to cervical internal carotid ligation for giant aneurysms in 7. The grafts were always harvested from the internal saphenous vein. The proximal site of implantation was CCA (2 cases), ECA (6 cases), ICA (1 case), superior thyroid A (2 cases)--i.e. 11 long grafts--and the trunk of the occipital A--i.e. short grafts in 5 cases. In this series, there was no mortality and no morbidity related to revascularization. The early patency rate, checked with arteriography, was 62.5% (10 cases) and the late one 56.2% (9 cases). Causes of failure, partially related to technical difficulties in 2 cases, were almost always due to an insufficient extra-intracranial pressure gradient (4 cases). Excepted in one case, there was no correlation between patency and the use or not of anti-aggregant and/or heparin. Literature data are summarized and discussed. They all confirm the importance--besides the absence of technical errors--of a sufficient extra-intracranial gradient for obtaining a good patency rate.