Intracranial arterial reconstructions with [[reimplantation]]s, [[reanastomoses]], in situ [[bypass]]es, and intracranial [[interpositional bypass]]es (third-generation bypasses) augment conventional extracranial-intracranial techniques (first- and second-generation bypasses) and generate innovative bypasses in deep locations, such as for [[anterior inferior cerebellar artery aneurysm]]s. When conventional combinations of [[anastomoses]] and [[suturing]] techniques are reshuffled, the fourth generation of bypasses results, with eight new types of bypasses. Type 4A bypasses use in situ suturing techniques within the conventional anastomosis, whereas type 4B bypasses maintain the basic construct of reimplantations or reanastomoses but use an unconventional anastomosis. [[Bypass surgery]] (605 cases) demonstrates that open [[microsurgery]] will continue to evolve. The best neurosurgeons will be needed to tackle the complex lesions that cannot be managed with other modalities. Becoming an open [[vascular neurosurgeon]] will be intensely competitive. The microvascular practice of the future will require [[subspecialization]], [[collaborative]] team effort, an [[academic]] [[medical center]], regional prominence, and a large catchment population, as well as a [[health system]] that funnels patients from hospital networks outside the region. [[Dexterity]] and meticulous application of microsurgical [[technique]] will remain the fundamental skills of the open vascular neurosurgeon
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)).