Authors: L. Nelson Hopkins, III
Hakeem Shakir, MD
"You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete." - R. Buckminster Fuller1
Leaders hip can be a difficult task for those involved in periods of rapid change and paradigm shifts. Leaders must demonstrate adaptability to change and willingness to approach problems from different vantage points during these situations to maintain ongoing growth. Neurosurgery was no stranger to the challenges confronting cerebrovascular specialists amidst the neuroendovascular revolution.
The visualization of the vasculature of various organs by direct puncture became possible with the discovery of angiography by Portuguese neurologist Egas Moniz in 1927.2 However, Moniz's encouraging innovation was fraught with risk. In 1953, Swedish radiologist Sven-Ivar Seldinger developed a technique to access the vascular system via the femoral artery.3 The improved technique was a development that made angiography safer and launched the future of endovascular methods.
Neurosurgeons began using carotid punctures in the 1950s to perform angiograms.4 In 1960, American neurosurgeons Alfred Luessenhop and William Spence reported the first embolization of an arteriovenous malformation (AVM) using pellets introduced into the cervical portion of the internal carotid artery. Then in 1964, Luessenhop and Velasquez succeeded in catheterizing intracranial cerebral vessels. However, radiologists resumed the lead as the demands of neurosurgery increased. With the exception of a few prominent neurosurgeons like Guido Guglielmi and Fedor Serbinenko,4, 5 radiologists directed the movement toward minimally invasive catheter-based approaches to vascular pathologies throughout the 1960s and 1970s.
Neurosurgeons traditionally favored open and very invasive approaches to intracranial aneurysms, AVMs, and fistulas. It is no mystery that young residency applicants of the past, and perhaps some today, were and are drawn to neurosurgery because of a preference for open cranial procedures rather than coiling or embolizing lesions through catheters from small access sites in the groin. The challenges of clipping aneurysms, resecting AVMs, and anastomosing cerebral vessels for surgical bypass undoubtedly attracted neurosurgeons whose affinity for an open view of the cerebrum often outweighed the growing trend toward minimally invasive methods.
In the 1970s, a handful neurosurgeons began treating central nervous system (CNS) diseases such as carotid-cavernous fistulas and AVMs with emerging endovascular approaches. Technology such as balloons and catheters were made or borrowed from other specialties and adapted to neurovascular problems. Advances in technology and improved methods would catalyze endovascular approaches to brain pathologies in the 1980s. Given their control of catheter angiography, neuroradiologists took the early lead in developing catheter-based approaches to the brain. Considering their familiarity with open approaches to cerebrovascular abnormalities and the complications associated with catheter-based approaches, neurosurgeons needed to learn catheter skills to participate in this growing field. However, there were significant challenges in crossing the bridge to learn catheter-based approaches with radiologists.
Neurosurgical endovascular training began in Buffalo, New York, in the early 1980s. The first neurosurgical endovascular fellowship program was established there in 1991. Today, endovascular neurosurgeons (ENS) are a dominant force in catheter-based therapies for brain and spine pathologies. This advancement was largely due to neurosurgeons' clinical skills and penchant for treating complex vascular lesions of the CNS. Other specialists, such as neurologists and even interventional cardiologists, have entered the field. Each specialty has a unique perspective and contributes to this rapidly expanding field.
The neurosurgical vascular community leadership initially eschewed reconsideration of the traditional approach to vascular disease. Progress in developing neurosurgical endovascular centers was slow and required dedication and perseverance.
By comparison, spinal surgery was traditionally a neurosurgical field. But as spinal reconstruction techniques evolved, orthopedic surgeons entered the field and made significant contributions. At several centers, combined neurosurgical-orthopedic programs have further advanced the field. Unlike spinal surgery, which occurred in an operating room and was familiar to neurosurgeons, endovascular treatments were not considered standard or routine for neurosurgeons during the 1990s. However, a number of neurosurgical centers began performing and teaching endovascular approaches. National neurosurgical meetings were rife with debates over endovascular versus open surgical approaches to the treatment of vascular diseases of the CNS. At the same time, radiology experts questioned whether neurosurgeons were skilled to perform endovascular procedures. Other specialties faced similar dilemmas as catheter-based therapies gained acceptance. An example can be observed in the history of cardiothoracic surgery. Cardiothoracic surgeons have seen their patients opt for less-invasive revascularization procedures performed by interventional cardiologists because they did not adopt progressive catheter-based approaches.
The senior author of this piece, despite doubt from some of his contemporaries, felt neurosurgeons ought to be involved in the leadership of endovascular therapies field because neurosurgeons have unique experience in open and intravascular approaches to vascular abnormalities of the CNS and are therefore capable of anticipating the complications associated with either approach. From teaching the first endovascular courses at annual meetings of the Congress of Neurological Surgeons to participating in clinical trials at our home institution, leadership from neurosurgeons was a necessity. Leadership meant much more than simply telling people "what to do" or "how to do it;" leadership required constant innovation and action in addition to building strategic partnerships.
Collaboration and cross-pollination with industry and other specialties has driven the neuroendovascular space forward. Headway began with publishing our data on carotid artery stenting and challenging the old mindset that endarterectomy was the only option. After pushing the endovascular envelope by participating in early trials for stroke stenting and thrombectomy,6 we continued to publish our findings and helped to lay the foundation for trials such as Solitaire with the Intention for Thrombectomy as Primary Endovascular Treatment (SWIFT PRIME)7 and Clinical Mismatch in the Triage of Wake Up, and Late Presenting Strokes Undergoing Neurointervention with Trevo (DAWN) (http://evtoday.com/2017/05/dawn-trial-results-presented-for-strykers-trevo-retriever) . Trials such as these have significantly advanced stroke intervention. Today, endovascular neurosurgery is one of the most sought-after subspecialties within neurosurgery, and the next generation of neurosurgeons is leading the cerebrovascular field. Some of the largest clinical trials in stroke and aneurysm treatment are led by neurosurgeons across the country. Thirty years ago, some would reject the notion of a neurosurgeon spending time in an angiography suite and treating vascular pathologies through femoral or radial access, but now neurosurgeons are leading the way in endovascular therapies.
"When envisioning the technologic process, we must 'think young' and consider the impossible. The mindset is best achieved in an environment where innovators consider the unachievable as being possible." - Thomas J. Fogarty8
- Fuller RB. Critical Path. 1st ed. New York: St. Martin’s Press, 1981.
- Moniz E, Dias A, Lima A. La radio-artériographie et la topagraphie cranio-encéphalique. J Radiologie 1928;12:72-82.
- Seldinger SI. Catheter replacement of the needle in percutaneous arteriography; a new technique. Acta radiol 1953;39:368-76.
- Alexander LF, Ward BA. The history of endovascular therapy. Neurosurg Clin N Am 1994;5:383-91.
- Guglielmi G. History of endovascular endosaccular occlusion of brain aneurysms: 1965-1990. Interv Neuroradiol 2007;13:217-24.
- Levy EI, Siddiqui AH, Crumlish A, Snyder KV, Hauck EF, Fiorella DJ, Hopkins LN, Mocco J. First Food and Drug Administration-approved prospective trial of primary intracranial stenting for acute stroke: SARIS (stent-assisted recanalization in acute ischemic stroke). Stroke 2009;40:3552-6.
- Saver JL, Goyal M, Bonafe A, Diener HC, Levy EI, Pereira VM, Albers GW, Cognard C, Cohen DJ, Hacke W, Jansen O, Jovin TG, Mattle HP, Nogueira RG, Siddiqui AH, Yavagal DR, Baxter BW, Devlin TG, Lopes DK, Reddy VK, du Mesnil de Rochemont R, Singer OC, Jahan R. for the SWIFT Prime Investigators. Stent-retriever thrombectomy after intravenous t-PA vs. t-PA alone in stroke. N Engl J Med 2015;372:2285-95.
- Fogarty TJ. Vision of relevant technologic progress for the next two decades. J Vasc Surg 1996;24:291-6.