Section Editor(s): Bendok, Bernard R. MD; Levy, Elad I. MD
Mount Sinai Hospital, New York, New York
Correspondence: Alejandro Berenstein, MD, Mount Sinai Hospital, 1000 10th Ave, Room 10G, New York, NY 10019. E-mail: firstname.lastname@example.org
This supplement explores recent advances and innovations in vascular neurosurgery. Over the past 3 decades, this field has undergone one of the most dramatic evolutions, or, more accurately, revolutions in medicine, thanks, in large part, to the participation of health care professionals across many disciplines.
A great treasure of this supplement is the rich bibliography that is evidence of the growing interest in this field, as well as the prolific developments in technology and understanding of the diseases. We are now able to regularly catheterize vessels of 100 μm and smaller with incredible accuracy and safety thanks to the technical advancements in endovascular navigation of the arterial, venous, and even capillary network, as well as the continuous improvements in imaging techniques. Superselectivity has allowed us to pursue the most elegant and ergonomic access to the most distal parts of the brain, head, neck, spine, and spinal cord by using minimally invasive methods. The development of increasingly reliable devices that have better tissue response (such as coils, biologically coated hydrocoils) has been complemented by the introduction of those that produce flow diversion and result in progressive obliteration of otherwise difficult, or impossible to coil, aneurysms (such as intracranial balloons, stents, and intraluminal higher-density stents). Most recently, intra-aneurysmal metal flow diverters have leap-frogged the endovascular therapy of aneurysms. Meanwhile, parallel advances in minimally invasive craniotomies were developed to compete with percutaneous catheterization, and are less traumatic than the more traditional craniotomies. Advances in revascularization of cerebral arteries by using higher-flow radial artery and venous grafts continue and, in properly selected clinical conditions, can further expand what we can achieve.
The use of liquid embolics has had a more important effect in the treatment of arteriovenous malformations than it has in aneurysms. The introduction of slowly vulcanizing mixtures has permitted more controlled penetration, whereas the combination of multiple catheters has expanded the technical reach of what we can embolize. The use of detachable-tip microcatheters will increase safety and efficacy during embolization. Onyx embolization of dural malformations represents a drastic change in our ability to cure these malformations and still preserve the sinuses in a large number of cases. This procedure has become the treatment of choice in most dural malformations. In those cases where a sinus cannot be preserved, the transvenous approach is very effective and safe in curing dural arteriovenous fistulas. When endovascular treatment is incomplete or impossible, the information acquired by superselective angiography will pinpoint the area that must be closed. At present, the goal in vascular neurosurgery is to have well-balanced teams of professionals that can select the best strategy to safely cure the patient.
The use of various radiosurgery strategies alone or in combination with embolization is becoming more creative, and can offer expanded indications for using radiosurgery not only after embolization, but for small surgical residuals. In appropriate cases, radiosurgery can be followed by embolization or microsurgery.
Rapidly evolving endovascular technologies for revascularization in the management of stenotic and ischemic disease are currently undergoing validation in comparison with medical or other surgical treatments and will be scrutinized in coming years. In ischemic stroke, the challenge is beyond technology, or proof of safety and efficacy. The challenge is to rapidly manage patients with this time-sensitive disease and to simplify the procedures so that they can be made available in small hospitals, and ambulances, or even at the site of occurrence in order to play a major role in large populations.
At present, surgical revascularization is reserved for some patients presenting with the heterogeneous gamut of the “moyamoya” group of diseases. The indications for the type of procedure to be used require careful selection that depends on multiple factors, including ethnicity, age of presentation, and clinical presentation (ie, ischemic vs hemorrhagic, potential etiologies). The benefits of surgical techniques are undergoing clinical trials, and the challenge of designing these trials illustrates the difficulty of studying the moyamoya group of diseases specifically, and cerebrovascular diseases in general.
Although our field currently emphasizes vascular and hypervascular diseases, our technical and imaging advances coupled with anatomic and physiological manipulations should permit us to expand our possibilities toward a territorial approach. Pursuing a territorial approach could allow us to isolate 1 anatomic area and manipulate and open the blood-brain barrier, permitting the delivery of treatments such as chemotherapy, genetic vectors, or other treatments. The introduction of transcatheter ultrasounds, lasers, or other modalities is now possible, with the future being limited only by our imagination.
Accreditation by the Council for Graduate Medical Education (ACGME), “Endovascular Surgical Neuroradiology” exists, but it is inefficient and requires compromises that limit training. The training of the next generation of cerebrovascular specialists must evolve differently. The needs of society are changing. Long “comprehensive” Halstedian model training schemes no longer apply. The present “boxes” or boards that certify specialists are biased both financially and by territorial interests. The enemy is the disease (ie, the aneurysm) not the surgeon, or the radiologist, or the neurologist. Despite requiring training in spine surgery, barium enemas, or electromyography, neither neurosurgery, radiology, nor neurology provide the most simple and basic sciences needed for endovascular surgery, such as vascular biology, vascular physiology, expertise in the coagulation cascade, and study of the endothelium, which is an incredibly unique organ.
It is clear that the way forward is a new specialty. Beginning in medical school, doctors should be trained as the endovascular surgeons. And if a student wants to learn microneurosurgery, he or she could add training in neurosurgical skills, or start with a neurosurgical residency.
An important omission in this supplement is the tremendous impact that the endovascular therapies of embolizations and sclerotherapy treatments have had on patients with vascular lesions of the head and neck. The use of percutaneous direct punctures by using ultrasound, or the fusion of magnetic resonance imaging and DynaCT guiding techniques, can safely reach deep head and neck and intraorbital lesions. At present, physicians coming from neurosurgery or neurology are not interested in this patient population because they do not have the training or the exposure to deal with these diseases, but the benefit they provide should be part of our practice.
The author has no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.