Transvascular neurosurgery

Major advances in cerebrovascular neurosurgery have repeatedly emerged from the convergence of a transformative idea with enabling technology. The introduction of the operating microscope and microsurgical instrumentation in the late 1960s redefined the limits of safe access to deep cerebrovascular structures and gave rise to microneurosurgery. The advent of catheter-based intracranial navigation in the late 20th century created the field of endovascular neurosurgery, transforming the management of aneurysms, arteriovenous malformations, dural arteriovenous fistulas, atherosclerosis, and large-vessel occlusion stroke. Throughout this evolution, the vessel wall has been treated as an inviolable barrier; the cardinal rule of endovascular practice has been to avoid perforating it. Herein, it is argued that the deliberate and controlled crossing of the vessel wall-transvascular neurosurgery-represents a third paradigm shift, whereby the neurovascular arterial and venous networks are repurposed as a natural operative corridor to access the subdural, subarachnoid, parenchymal, and ventricular compartments of the brain without a craniotomy or burr hole. Early clinical work has shown that controlled transvascular exit from the meningeal vasculature is feasible and can enable a range of intracranial procedures, from implantation of biomimetic shunts and combined middle meningeal artery embolization with transarterial evacuation of nonacute subdural hematoma. The authors review the historical arc that brought us to this point, summarize the technical and biological rationale for meningeal-vascular access, and outline a roadmap by which a broad ecosystem of transvascular neurosurgical procedures could be performed through rapid, outpatient, catheter-based workflows.