Cervical carotid to vertebral artery high-flow interposition graft bypass serves as an extracranial communicating pathway between anterior and posterior circulation for vertebrobasilar lesions.

PURPOSE: Conventional surgical techniques for posterior circulation bypass have certain limitations, necessitating innovative approaches. This study evaluates the indications and outcomes of cervical carotid-to-V2 vertebral artery bypass-functioning as an extracranial "posterior communicating artery"-in the treatment of vertebrobasilar lesions.

METHODS

The V2 bypass procedure via a cervical anterolateral approach was applied in cases of (1) bilateral vertebral artery (VA) occlusions (Type I), (2) subclavian artery (SBA) occlusion with steal phenomenon (Type II), and (3) compensated posterior circulation aneurysm (Type III).

RESULTS

All eight patients exhibited patent bypass grafts. In seven cases with anterior-to-posterior bypass flow, the carotid artery supplied the entire vertebrobasilar territory. All four Type I patients showed improved regional cerebral perfusion. Among the three Type II patients, two (with a non-dominant contralateral VA) underwent VA ligation, resulting in significant reduction of blood steal. In one patient with bilateral symmetric VAs, VA ligation was not performed due to personal reasons, and hemodynamic status remained unchanged. One Type III patient showed contrast retention within the aneurysm sac and progressive shrinkage following bypass.

CONCLUSION

The V2 bypass uses a short interposition graft between the anterior and posterior circulations, offering high flow and orthograde perfusion without complex skull base manipulation. This technique simplifies revascularization for posterior circulation ischemia, mitigates steal phenomena in SBA occlusion, and enables trans-circulatory flow modulation for compensatory aneurysms.