Evolution in Cerebrovascular Bypass: Conceptual Framework, Technical Nuances, and Initial Clinical Experience with Fourth-Generation Bypass.

Cerebrovascular bypass has undergone a remarkable evolution since its initial description. Recent developments have required the conceptualization of a fourth generation in bypass techniques, encompassing both unconventional suturing techniques (type 4A; eg, intraluminal suturing) and atypical vascular constructs (type 4B; eg, middle communicating artery bypass). This cohort study reports 44 bypass operations performed by a single cerebrovascular neurosurgeon from 1997 to 2021 among a total cohort of 750 bypasses. Most bypasses were for the treatment of complex aneurysms (36 of 44 cases, 89%). Although challenging, these operations empower novel approaches to a variety of otherwise untreatable lesions.