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Endovascular Neuroradiology The New Frontier

Dr. Sean Lavine

Today we are seeing the integration of medicine and technology like never before and nowhere is this more true than in a subspecialty of medicine you may never have even heard of called Endovascular Surgical Neuroradiology (ESNR).  ESNR is formally defined by the Accreditation Council for Graduate Medical Education as “a clinical subspecialty for the diagnosis and treatment of neurovascular diseases using x-ray fluoroscopy and angiography.”

What this means is that surgeons can find and fix problems with our blood vessels from the inside out.  Using tiny instruments, powerful imaging technology, and sophisticated computer integration, surgeons can actually travel throughout the body and deep into the brain using our vessels themselves.

ESNR’s appeal is that it offers clinicians less invasive alternatives to traditional surgical procedures. They can more accurately target lesions with smaller incisions, cause less damage to surrounding tissue, and do it all with less blood loss.  What this means to their patients is less pain and a quicker recovery.

Here at the Department of Neurosurgery are three specialists in this area, Dr. Sean D. LavineDr. Philip M. Meyers and Dr. Jobyna Whiting from the Endovascular Center, who are helping us to understand this innovative and emerging field of medicine.

According to the Center’s doctors, “ESNR is still in its formative years.”  Previously called Interventional Neuroradiology, just four years ago the name was changed to ESNR and the practice guidelines were broadened to accommodate more areas of medicine including neurology, neurosurgery, radiology, vascular surgery, and cardiology.

Probably the most commonly known use of ESNR is in the treatment of  atherosclerosis or narrowing of blood vessels from plaque buildup. Clogged arteries, either inside the brain or that feed the brain, are one of the leading causes of stroke.

The standard surgical treatment has been endarterectomy where surgeons actually open up the artery and remove the plaque. This can be very effective, especially with the carotid artery in the neck.  But, when the location of the artery is harder to get to, like when it is inside the brain, or if standard open surgery is too risky, an ESNR technique called angioplasty can be preferable.

The first balloon angioplasty was performed on the carotid artery in 1980.  Here, a tiny balloon is inserted in the narrowed vessel and inflated to widen the opening.  It is then deflated and removed.

Over time, this technique has been augmented with the use of stents and vascular filtration devices.  A stent can hold the walls of the narrowed blood vessel open with or without angioplasty. A vascular filtration device is used to keep pieces of plaque or blood clots from migrating away from the surgical field and preventing strokes when the stent angioplasty is taking place.

To actually extract clots from vessels, two other ESNR methods have also emerged, the Merci Device and the Penumbra Device.  According to Lavine, “The Merci Device was specially designed and tested for extracting clots from major cerebral arteries.  However, some stroke specialists have questioned the effect on patient outcome making this an area of continued clinical investigation.”

Dr. Lavine continues, “We also use the Penumbra Device to mechanically remove the stroke-causing clots with a microcatheter suction device delivered directly to the clot in the brain.”  Despite some controversy, there is tremendous interest in these techniques and the possibility of near-term medical advancement.

Dr. Philip Meyers

When talking about ESNR, Lavine and Meyers usually start by talking about the treatment of another condition, Cerebral Aneurysms.  They say, this is the new  “proving ground for ESNR.”

A cerebral aneurysm occurs when part of the wall of a blood vessel in the brain becomes thinned or damaged and bulges or balloons out. They are often only discovered once they have burst and caused a brain hemorrhage.

They can be surgically treated before or after they burst. The traditional treatment is called surgical clipping.  In this type of open brain surgery, surgeons place a clip at the base of the aneurysm to stop it from bleeding if it has ruptured, or to stop it from filling if it has not.

After 1990, with the introduction of the Guglielmi Detachable Coil, a new ESNR alternative became available called endovascular coiling. Through an artery in the groin, surgeons can reach the aneurysm and place a number of tiny flexible coils inside it.  This stimulates the formation of a clot that later heals and prevents the aneurysm from bursting.  This treatment  has become even more effective with the recent introduction of Bioactive coils.

The use of coils was until recently only possible in the type of aneurysm that has a narrow base or “neck.”  Surgeons were able to coil wide-necked aneurysms after 2002 when a stent, or mesh device, was designed for use at the base of the aneurysm to keep the coils from falling back into the main artery.

Shortly after the coil’s introduction, a large multi-year study, the International Subarachnoid Aneurysm Trial (ISAT), was implemented to compare clipping with coiling in unruptured aneurysms.  This study concluded in 2003 when it became clear that coiling had a better outcome. For unruptured aneurysms though, there is still some controversy as to which method is most effective. See our blog: Results From First IML: Aneurysm Coiling V. Clipping Still A Toss Up for more on this.

ESNR is also commonly used as an adjunct in the treatment of Arteriovenous Malformations (AVM).   Research has shown that preoperative endovascular embolization or “gluing” of the AVM to keep it from bleeding when operated on makes the surgery safer. To learn more about this technique see our blog: New Study Finds Little Risk And Much Benefit In “Gluing” Blood Vessels Before Surgery.

Similar ESNR techniques are being used to embolize the arteries that feed brain tumors before they are surgically removed.  This reduces the tumor’s blood supply and according to Lavine, “This benefits the patient in that it makes the surgical time shorter and there is less blood loss.”

ESNR techniques are also being used outside the fields of cardio and cerebrovascular medicine.   Spine surgeons are increasingly using ESNR techniques in the treatment of certain causes of back pain. In particular they are finding success with facet joint arthropathy, osteoporotic Vertebral Compression Fractures, and Spinal Tumors.  Using a minimally invasive, radiologically guided procedure they can treat the pain and disability by injecting cement to stabilize the area.

ESNR is an exciting new arena and more doctors are jumping on board.   A report authored by members* of the Department of Neurosurgery, including Lavine and Meyers, contained surveys they conducted that show more fellows and residents are venturing into this new field than ever before and that this trend is primed to continue.

They are also seeing a change in the faculty of ESNR programs.   The authors say, “While the majority of current faculty are still neuroradiologists, our study indicates that a shift is afoot and that neurosurgeons and neurologists will eventually outnumber their colleagues in radiology.”

The science is moving fast and with that comes some controversy, but without a doubt, this is a new frontier and the benefits to patients are only just beginning.

To learn more about this growing subspecialty see Dr. Sean Lavine and Dr. Philip Meyers’ chapter on the subject in the 12th edition of Merritt’s Neurology.

Also see our related Blogs: New Study Finds Little Risk And Much Benefit In “Gluing” Blood Vessels Before Surgery , Endovascular Surgery: To Clot Or Not To Clot, Results From First IML: Aneurysm Coiling V. Clipping Still A Toss Up


* Doctors who surveyed the ESNR Progams are: Dorothea Strozyk, MDSimon Hanft, M.D; Christopher Kellner M.D.; Philip M. Meyers, M.D.; and Sean D. Lavine, M.D..

patient journey

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