A Lasting Future for Open Vascular Neurosurgery

Open vascular neurosurgery has been transformed by the widespread implementation of endovascular techniques and stereotactic radiosurgery. Aneurysms once treated with microsurgical clipping are now coiled, pipelined, or treated with intravascular flow diverters. Aneurysms at the basilar bifurcation and paraclinoid internal carotid artery, which helped incorporate orbitozygomatic craniotomies and anterior clinoidectomies into open vascular neurosurgery, are no longer routinely clipped, and many trainees have never seen these skull base surgical techniques. Similarly, arteriovenous malformations (AVMs), once resected microsurgically, are now typically embolized and treated with radiosurgery or managed conservatively. Open vascular case volume has decreased, and more neurosurgeons use a hybrid open and endovascular approach focused on the specific disease rather than on particular operative techniques. These trends, combined with the advent of mechanical thrombectomy for treating acute ischemic stroke, economic pressures, and convenience, have led many cerebrovascular neurosurgeons to favor endovascular therapies.

This issue of Neurosurgery Clinics of North America is an update on how open vascular neurosurgery has responded to these developments. First, microneurosurgeons have focused on complex cases that are less favorable for endovascular therapy, for which microneurosurgery is more efficacious, or that require a multimodal approach. Articles in this issue on wide-neck and bifurcation aneurysms, giant aneurysms, and dolichoectatic vertebrobasilar aneurysms exemplify this willingness to tackle the most challenging aneurysms. Second, microneurosurgeons continue to innovate and advance open techniques. Articles on novel bypasses and fourth-generation constructs, as well as transcavernous approaches, exemplify this increasing technical sophistication. Third, microneurosurgeons have redoubled efforts to treat pathologies for which endovascular therapy is limited, namely cerebral cavernous malformations and AVMs. Articles in this update examine the state of surgical practice for these two key lesions. Fourth, open vascular neurosurgery is changing with the integration of technology and its delivery to patients. This update addresses minimally invasive aneurysm surgery performed in the outpatient setting, endoscopic techniques, use of the exoscope, and the application of big data and artificial intelligence. Last, microneurosurgeons are conducting laboratory research to identify novel therapies for aneurysms and other vascular lesions, both technical and pharmacologic. This research includes studies on the hemodynamics and biology of aneurysm rupture and AVM formation and anatomical studies as the basis for new surgical approaches and devices.

Open microsurgery has a lasting role in vascular neurosurgery. As this issue demonstrates, open microsurgery may be superior to endovascular therapies in treating patients with complex aneurysms. Brainstem cavernous malformations exemplify how fresh insights and the application of open microsurgical skills can expand vascular neurosurgery. AVMs demonstrate that, even as other modalities minimize invasive interventions, occlusive and obliterative therapies remain inferior to resective therapies. Open microsurgery is and should remain a cornerstone of neurosurgical culture because it offers anatomical insights that result from direct contact with pathology, which is difficult to obtain from radiography alone. Instruments under the microscope respond to the hands with precision, and we should not relinquish this power. Our very best neurosurgeons must be capable of repairing complex lesions that cannot be managed in any other way. Manual dexterity and technical skill still matter. Anastomoses that have existed for decades produce some of neurosurgery’s most artful constructs, and we resort to old-fashioned techniques when cutting-edge devices fail. Modern neurosurgery has been shaped by endovascular technology, radiosurgery, endoscopy, minimally invasive techniques, and biologic therapies that demand little of the neurosurgeon. Open microsurgery resists these trends by emphasizing a few simple instruments, steady hands, and meticulous technique. The craft will last and remain relevant if enough creative surgeons continue to engage our hands, heads, and hearts in treating our most complex and difficult lesions.