Summary of Phase 2 surgical management (VA to SCA bypass), with combined (A)
temporal and (B) far lateral craniotomies through a single incision, (C)
exposure of the donor V3 segment of VA and recipient SCA, (D) completion of the
graft to SCA anastomosis, and (E) graft to VA anastomosis with clip occlusion of
the dominant VA either extradurally (V3) or intradurally (V4). Suboccipital
craniectomy and duroplasty creates space to accommodate cerebellar swelling.
Abbreviations: ICA = internal carotid artery; A1 = anterior
cerebral artery, A1 segment; M1 = middle cerebral artery, M1 segment; BA
= basilar artery; VA = vertebral artery; PICA =
posterior inferior cerebellar artery; SCA = superior cerebellar artery;
PCA = posterior cerebral artery; RAG = radial artery graft; IX
= glossopharyngeal nerve; X = vagus nerve; XI =
accessory nerve.