Anatomic basis for the treatment of aneurysms of the upper cervical segment of the internal carotid artery by extra- intracranial cervico-petrous bypass with inverted "in situ" saphenous vein graft

In the surgical treatment of aneurysms of the upper cervical portion of the internal carotid a., exclusion of the affected vascular segment combined with an extra-anatomic cervico-petrous bypass using a vein graft (great saphenous v.) may be considered. One of the problems specific to these extra-anatomic bypasses is asociated with the sub-cutaneous positioning of the vein graft, exposing it to risks of angulation, torsion or extrinsic compression that may lead to early venous thrombosis. We suggest an alternative technique using the principle of telescoping and consisting of positioning the vein graft within the cervical portion of the artery (" in situ" bypass). The cervical portion of the ICA may be used as a tunnel for the vein graft since there are no collateral arterial branches at this level. The technical features of such a bypass are defined by means of an anatomo-surgical study in the cadaver: exposure of the petrous portion of the internal carotid a. in its horizontal segment by subtemporal access, exposure of the ICA in the neck, transverse arteriotomies of the ICA, angioplasty with a Fogarty balloon, intracarotid telescoping of a saphenous vein graft from the cervical to the petrous region, distal end-to-end anastomosis between the vein graft and the petrous portion of the ICA, and proximal end-to-end anastomosis between the vein graft and the cervical portion of the ICA.