Extracranial Carotid-Vertebral Bypass for Endovascular Access to Complex Posterior Circulation Aneurysms

BACKGROUND: Endovascular embolization is a desirable treatment option for complex posterior circulation aneurysms, particularly recurrent aneurysms or those in difficult-to-access surgical locations. However, endovascular access is occasionally prohibited by proximal vertebral artery (VA) occlusion or vessel tortuosity. One strategy in such instances involves creation of an extracranial bypass conduit to the distal VA. OBJECTIVE: To describe a novel strategy to allow for endovascular treatment of aneurysms at high risk for direct surgery. METHODS: Three cases of carotid-VA bypass performed to provide endovascular access to posterior circulation aneurysms were identified. The clinical indications, radiographic characteristics, operative technique, and outcomes were reviewed. RESULTS: Indications for bypass were previously clipped recurrent basilar tip aneurysm, previously coiled midbasilar aneurysm with compaction requiring stent placement, and distal intracranial VA aneurysm with iatrogenic vertebral dissection/occlusion after initial coil attempt. In all cases, routine endovascular access for primary or stent-assisted coiling was prohibited by VA tortuosity. Bypass with the use of interposition saphenous vein grafts was successfully performed to the C1-C2 region of the V2 segment without complications. The bypass was followed by successful endovascular treatment in all cases 2 to 6 weeks after surgery. In 1 patient, 2 recurrent treatments through the graft were subsequently performed for coil compaction. CONCLUSION: Extracranial carotid-VA bypass can be a valuable tool in the management of complex posterior circulation aneurysms. It is a safe and efficacious technique providing a conduit for repeated access to the posterior circulation in patients with otherwise prohibitive vertebral anatomy.

Thyrocervical trunk—external carotid artery bypass for positional cerebral ischemia due to common carotid artery occlusion

✓ Medically refractory positional cerebral ischemia (PCI) and concomitant orthostatic hypotension associated with chronic common carotid artery (CCA) occlusion are rare. In this technical report, the authors describe an extracranial bypass in which the thyrocervical trunk was used as a donor vessel to treat three cases of CCA occlusion with PCI. Postoperatively, although orthostatic hypotension remained, ischemia-related symptoms resolved in all three patients and long-term graft patency was demonstrated. It is possible to treat cerebral ischemia due to CCA occlusion with extracranial bypass surgery. In these patients, the thyrocervical trunk proved to be a suitable donor vessel for the reconstitution of blood flow within the external carotid artery.

Thyrocervical trunk–external carotid artery bypass for positional cerebral ischemia due to common carotid artery occlusion

Medically refractory positional cerebral ischemia and concomitant orthostatic hypotension associated with chronic common carotid artery (CCA) occlusion are rare. The authors detail their experience with three cases treated exclusively by an extracranial bypass in which the thyrocervical trunk was used as the donor vessel. Postoperatively grafts were patent and symptoms resolved in all three patients, although orthostatic hypotension remained. Postural cerebral ischemia due to CCA occlusion can be treated by extracranial bypass surgery. The thyrocervical trunk is a suitable donor for reconstruction of the external carotid artery in these cases.