With the ELANA technique, a whole new spectrum of possible bypasses opens up in vascular neurosurgery. Because of the different possible proximal locations it can facilitate a high flow in the original direction of the bloodflow.
Extra-Intracranial High-Flow Bypass
As a proximal, extracranial anastomosis site the external carotid artery (ECA) or the superficial temporal artery (STA) can be chosen. This is preformed in a conventional way because, except from a small group of patients with an occluded ICA and collateral ophthalmic flow, patients tolerate temporary occlusion time in these regions. The distal anastomosis can be made in any area suitable for ELANA.
Schematic overview of an extra-intracranial bypass from the ECA to the ICA (left and the STA to the ICA (right). The bypass conduit can be constructed behind or in front of the ear. Indications could be giant ICA aneurysm, an occluded ICA or skull base tumors(see ‘ indications’ under ). Recently a mean postoperative flow of 156 cc/min was reported through these kind of ELANA Ec-Ic bypasses.
Intra-Intracranial High-Flow Bypass
The ELANA can also be used for Ic-Ic bypass grafting for more peripheral pathology. Depending on recipient size, degree of arteriosclerosis and if the site is surgical reachable, a proximal and distal ELANA or only a proximal ELANA can be perormed. Examples are shown in figure 3
Left: Ic-Ic bypass from the ICA bifurcation (ELANA) to an M3 branch of the MCA (conventional). Note that if an M2 branch is reachable with a minimal diameter of 2.5 mm without arteriosclerosis, an ELANA would be preferable. Mean flow of 53 cc/min was recently reported through these ELANA bypasses. Middle: Ic-Ic bypass from the ICA bifurcation (ELANA) to a right A3 branch (Conventional). Right: Ic-Ic bypass with a proximal (ICA) and distal (P1 part of PCA) ELANA anatomosis.