Dec. 29, 2017
With the development of new neurovascular techniques, treatment options for patients with intracranial aneurysms have vastly improved. However, the optimal use of the multiple possible treatment modalities — and decisions about which aneurysms to treat — require sound diagnostic and surgical skills. Neurovascular surgeons at all three Mayo Clinic campuses have the experience and expertise to successfully manage these complicated cases.
"We are able to treat complex patients with very low morbidity and mortality. Equally important, we are able to differentiate between dangerous aneurysms that need treatment and the large number of aneurysms that are absolutely innocuous and don't need treatment," says Giuseppe Lanzino, M.D., a consultant in Neurosurgery at Mayo Clinic in Rochester, Minnesota.
In addition to fully equipped neurological intensive care units, Mayo Clinic also provides round-the-clock coverage by fellowship-trained neurovascular surgeons. "Our depth of expertise means that we have individual neurovascular surgeons who can perform whatever the patient needs — such as extracranial to intracranial bypass, coiling, stenting or microvascular procedures," says Bernard R. Bendok, M.D., chair of Neurosurgery at Mayo Clinic in Phoenix/Scottsdale, Arizona. "Many of these techniques were pioneered by Mayo Clinic neurosurgeons."
Prioritizing the patient's needs
As members of a group practice, Mayo Clinic neurosurgeons make treatment decisions based on the individual patient's needs, free of incentives to recommend unnecessary surgery or a particular technique. "It's important for patients to hear about all treatment options and their particular benefits," Dr. Bendok says. "Telling the patient only about the technique preferred by the surgeon would go against the Mayo Clinic model."
"Every aneurysm and every patient is different," adds Leonardo Rangel Castilla, M.D., a consultant in Neurosurgery at Mayo Clinic's campus in Minnesota. "Being trained in both open vascular and endovascular neurosurgery gives us a full understanding of intracranial vascular anatomy and pathophysiology, and allows us to tailor treatment based on the patient's condition and the anatomy of the aneurysm."
When appropriate, Mayo Clinic neurosurgeons use minimally invasive techniques, such as modified eyebrow incision, endoscopic skull base surgery, and transnasal and transcranial endoscopy. "The modern care of aneurysms requires a team that has wide expertise in these minimally invasive techniques and access to the very latest neuronavigation technology," Dr. Bendok says.
When making recommendations about treatment, Mayo Clinic neurovascular surgeons consider a constellation of factors, such as the patient's age and comorbidities and the aneurysm's size, shape and location. The complex decision-making is facilitated by the surgeons' extensive experience. "I have followed more than 1,200 patients with unruptured aneurysms," Dr. Lanzino says. "Over the years you acquire a set of skills to analyze each patient to determine whether an aneurysm is dangerous."
It's also common for Mayo Clinic neurosurgeons to review cases in conference with colleagues who have decades of neurovascular experience. "We learn from sharing previous experiences. It's a pool of experts giving a recommendation, not a single surgeon," says Rabih G. Tawk, M.D., a consultant in Neurosurgery at Mayo Clinic in Jacksonville, Florida.
Patients also benefit from Mayo Clinic's highly skilled interventional radiologists, neuroradiologists and vascular neurologists. "Vascular wall imaging can tell us if the walls of an aneurysm are inflamed and indicate whether there is a high risk of rupture," Dr. Tawk says. "Our neuroradiologists and vascular neurosurgeons work together to develop these imaging modalities."
Before complex surgeries, Mayo Clinic also has the resources to engage in simulations of the procedure on a computer or a 3-D-printed model of the patient's anatomy. "We can use these pre-surgical simulations to determine the best surgical techniques for that patient, to plan the procedure and then practice it on a physical model," Dr. Bendok says.
Placement of a flow diverter in a patient with an intracranial aneurysm
Angiograms illustrate the successful placement of a flow diverter in a patient with an intracranial aneurysm complicated by a dissected carotid vessel. A. Stents had been placed in the carotid artery before the aneurysm at another center. B. A Mayo Clinic neurosurgery team successfully crossed the stents to gain access to the aneurysm. C. The flow diverter was deployed. D. Final angiogram shows perfusion after treatment.
Collective wisdom and pre-surgical preparation are especially important for patients with complex intracranial aneurysms. Dr. Tawk describes a patient who came to Mayo Clinic's campus in Florida after three unsuccessful attempts elsewhere to have a flow diverter implanted for treatment of an aneurysm that was causing double vision.
"The complication was that the vessel dissected, and there were stents that were placed in the carotid artery before the aneurysm. Crossing those stents is very complex," Dr. Tawk says. "I ended up going step by step, first crossing the stents and then putting a balloon inside the stents and opening them up to create a pathway to the aneurysm where I needed to place the flow diverter. We successfully implanted the device, and a day later the patient went home."
At the forefront of clinical trials
Since the 1990s, Mayo Clinic has participated in major clinical trials leading to new treatment approaches for intracranial aneurysms. Most recently, Mayo Clinic was part of the multicenter International Study of Unruptured Intracranial Aneurysms (ISUIA), which defined indications for treatment and possible complications, as well as the Pipeline for Uncoilable or Failed Aneurysms (PUFS) trial, which led to the approval of flow diverters. Dr. Bendok serves as principal investigator of the Hydrogel Endovascular Aneurysm Treatment (HEAT) coiling trial.
Other Mayo Clinic studies have addressed the long-term safety of flow diverters, as described in the October 2017 issue of Journal of Neurosurgical Sciences, and the long-term clinical outcomes of stent-assisted embolization for wide-neck aneurysms, as reported in the February 2016 issue of Neurosurgery.
"Studies done at Mayo Clinic guide the treatment decisions of doctors worldwide," Dr. Lanzino says. "Our expertise is based partly on the fact that we not only treat patients but also study the disease."
For more information
Morales-Valero SF, et al. Low frequency of delayed ischemic events on MRI after flow diversion for intracranial aneurysms. Journal of Neurosurgical Sciences. 2017;61:459.
Brasiliense LB, et al. A reappraisal of anterior communicating artery aneurysms: A case for stent-assisted embolization. Neurosurgery. 2016;78:200.