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Year : 2018  |  Volume : 4  |  Issue : 1  |  Page : 55-59

What is the Safest Specialty to Perform Neuroendovascular Procedures for Cerebral Vascular Lesions? What Should We Tell Our Patients?

1 Neurosurgery Department, Neurosurgery Teaching Hospital, Baghdad University, Baghdad, Iraq
2 College of Medicine, Baghdad University, Baghdad, Iraq
3 Neurosurgery Department, Universidad de Cartagena, Cartagena de Indias, Colombia

Date of Web Publication27-Mar-2018

Correspondence Address:
Luis R Moscote-Salazar
Universidad de Cartagena Cartagena de Indias
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/mamcjms.mamcjms_4_18

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How to cite this article:
Hoz S, AbdulAzeez MM, Borhan M, Al-Awadi OM, Moscote-Salazar LR. What is the Safest Specialty to Perform Neuroendovascular Procedures for Cerebral Vascular Lesions? What Should We Tell Our Patients?. MAMC J Med Sci 2018;4:55-9

How to cite this URL:
Hoz S, AbdulAzeez MM, Borhan M, Al-Awadi OM, Moscote-Salazar LR. What is the Safest Specialty to Perform Neuroendovascular Procedures for Cerebral Vascular Lesions? What Should We Tell Our Patients?. MAMC J Med Sci [serial online] 2018 [cited 2020 Jul 7];4:55-9. Available from: http://www.mamcjms.in/text.asp?2018/4/1/55/228648


For the vascular diseases of the central nervous system (CNS) (e.g., arteriovenous malformation or intracranial aneurysms, etc.), treatment regimens may include endovascular interventions or open surgeries. Because open surgery is the fundamental job of the neurosurgeon, the endovascular procedures have variable concepts regarding the subspecialty of the physician who would be responsible for performing this kind of intervention.

Endovascular surgical neuroradiology (ESN) is a clinical subspecialty for the diagnosis and treatment of neurovascular diseases using X-ray fluoroscopy and angiography. ESN was previously called as interventional neuroradiology, but trainees with a neurology background were also included.[1]

Egas Moniz, a Portuguese neurologist in the 1920s, is regarded as the pioneer who performed the first cerebral angiogram in 1927.[2] Interestingly, Moniz did receive the Nobel Prize in 1949, not for his work on cerebral angiography, but rather for his work on frontal leucotomy.[3]

The endovascular treatments of the vascular or tumor diseases of the CNS have been developing since the late 60s and have now reached a phase of maturation. Initially, such treatments were performed by neurologists, neurosurgeons, anatomists, as well as radiologists.[4]

“Interventional neuroradiology,” “Surgical neuroangiography,” “Endovascular neurosurgery,” or “Minimally invasive neurological therapy” is nowadays still being practiced by physicians from various medical backgrounds. In Europe, it is mostly performed by interventional neuroradiologists. In North and South America, the process of embolization is shared mainly by neurosurgeons and neuroradiologists, whereas in Japan, most of the procedures are being performed by neurosurgeons. Neurointerventional therapies were not a natural extension from diagnostic cerebral angiography. These therapies were developed by physicians who were first and foremost clinicians, but dared to pioneer the riskier work with the goal of developing effective neuroendovascular therapies.[4]

The basic principle of all endovascular procedures (regardless of specialty) involves percutaneous entry into the femoral, radial, or brachial artery. Guide catheters or sheaths are introduced through the aorta into the supra-aortic vessel of interest. Microcatheters, balloon catheters, and stent delivery devices are introduced through the guide catheter and guided to the target lesion with flexible microwires. The advanced designs of microcatheters including flow-directed microcatheters have allowed the highly selective delivery of coils, embolic materials, and drugs into the regions of interest.[5]

Endovascular technology is evolving so rapidly, that by the time the outcome data are published, the devices are already obsolete, and their next iterations are already widely used.

As technology evolves and current trends keep progressing, the proportion of aneurysms safely treated using endovascular methods will likely be increased. This leaves only the most challenging aneurysms to undergo open surgical treatment.[6]

Endovascular techniques do not yet cover the full variety of complex aneurysms.[6] For example, there are about 10 types of aneurysms that may not be appropriate for endovascular coiling and open cerebrovascular surgery remains essential, such as wide-necked aneurysms located at the branch points of major vessels, large saccular aneurysms with multiple efferent arteries, dolichoectatic aneurysms, and large aneurysms with mass effect; when there are technical complications with endovascular intervention, as well as when patients cannot tolerate or have contraindications to antiplatelet therapy, in the setting of a subarachnoid hemorrhage, aneurysms located on small or very tortuous vessels may not be accessible via microcatheters, blister aneurysms, or pseudoaneurysms.[7],[8],[9]

For a complex vascular lesion, the endovascular intervention is not a real minimally invasive procedure, because the procedure may last for several hours or several sessions under general anesthesia, with an increased risk of arterial dissection or vasospasm or thrombosis with time, especially while using bilateral portal or double catheter techniques.

We reviewed the literature for this conflict topic to gain knowledge regarding the current concept that should be delivered to the medical community and may be to our patients regarding which is the best subspecialty to perform the endovascular procedures. We have tried to describe the pros and cons regarding each specialty for performing the neuroendovascular interventions. We are not trying to exclude any specialty but to raise awareness about the current situation and the need for each specialty to be a cut above the rest to perform these procedures.

  Radiologists Top

Literature dealing with neuroendovascular procedures tend to support their interventions as the exclusive treatment for many vascular lesions, as a recommended part of treatment for most of vascular lesions, and as the initial diagnostic angiography indicated for all CNS lesions suspected to be vascular, except very rare conditions.

Interventional neuroradiologists were the pioneers in developing this area of therapy, but the number of neurosurgical trainees in neuroendovascular treatment is increasing. In addition, other specialties, including neurology, vascular surgery, and cardiology, are now gaining access to the field of neuroendovascular treatment.[10]

Interventional radiology is in danger; this aspect is indisputable. Modern interventional radiologists complain about limited direct access to patients, as well as the lack of own beds and staff. Some believe that interventional radiology becoming a specialty of its own would solve these problems. This, however, is wishful thinking.[11]

Radiology, regardless of its technique and area, is a diagnostic specialty. Thus, patients who get intervened by interventional radiologists are not hospitalized in radiology departments and are not under the physical, legal, and financial responsibility of therapeutic radiologists.

If there is a debate on how interventional neuroradiology therapy is or should be organized, it is because these procedures are against radiology’s primary goal, which is the diagnosis of disease. Notably, this objection is becoming progressively ostensible. The operator participates in the diagnostic evaluation, proposes treatment, informs the patient and his/her advocates, obtains consent on the risks and potential complications of the procedure, performs the procedure, follows up after the procedure and prescribes appropriate postprocedure medical treatment, orders the patient’s release, writes the hospital summary, sees him/her at follow-up visits, is liable, and carries insurance. For all purposes and intents, the radiologist treats the patient. This new therapeutic specialty is no longer anything in common with radiology, apart from using X-rays. How confusing for the patients and their advocates! If we were the patients, wouldn’t we prefer to be treated by bona fide therapists, that is, therapists with hospital staff and beds?[12]

Clinical life is usually out of scope for the radiologist. It has been may be around 5–10 years since the radiologist visited the patients’ wards and conducted patient tour and follow-up. In addition, the radiologist’s daily practice does not involve dealing with the patient or patient’s relatives, informing them about the conservative vs. interventional vs. surgical options, and discussing the risks related to each procedure, rather than simply describing the surgical options and possible complications. The last issue can be also applied to the neurologists.

One cannot consider that INR only belongs to the radiology specialty because the environment in which INR is being performed in is the angiographic suite, which is usually located in the radiology department. Such views appear to be outdated, as is evident by the evolution of the procedure and the experiences around the world.[13]

One critical issue to be raised here is regarding the list on critical findings, which must be considered in each neuroradiology department. This list contains findings that must be brought to the notice of the referring physician, because it denotes a patient is at risk. One of the studies regarding the critical finding list showed that “of the surveyed neuroradiology programs that responded, less than a half (41.2%) had critical findings lists that they disseminated during orientation and most neuroradiology critical findings lists were created by radiology departments without the input from neurology, neurosurgery, or otolaryngology departments. There was a great variability in the length and content of the lists. Training programs with no critical findings lists contacted the referring physicians and discussed radiographic findings based on common sense, clinical judgment, or word of mouth!”[14]

  Cardiologists Top

Specialty societies in vascular surgery and cardiology have developed short courses of instruction to allow their diplomates to perform neuroendovascular procedures. This has had the effect of rapidly increasing the number of physicians who have been trained to perform neuroendovascular procedures, often with little or no understanding of the nervous system or cerebrovascular anatomy and pathophysiology. The biggest threat is from interventional cardiologists who exist in large numbers, possess catheter skills, have access to angiographic imaging, have demonstrated a desire to do procedures, and who have the infrastructure for patient access and follow-up. Cardiologists already perform the majority of carotid stenting procedures in the United States, and they have no plans to stop at the cranial base.[10]

  Neurologists Top

The literature for neurologists obviously tries to push the younger generations of neurologists toward availing opportunities to be more involved in the neurointerventional procedures. The following are examples of article titles from literature: “The need for interventional neurologists is growing”[5] or “Interventional Neurology, a subspecialty whose time has come.”[15] Picard felt neurology to be the logical choice, but he did not find it very effective in the 1960s. Conversely, he felt neurosurgery to be too aggressive. Neuroradiology appeared to him to be poised to undergo immense development with the potential for what he described as having “grand efficacy.”[4]

As we described earlier, dealing with patients or patients’ relatives, telling them about conservative vs. interventional vs. surgical options, and discussing the risks related to each procedure, rather than simply describing the surgical options and possible complications, are not the usual daily practice for neurologists.

Another issue is that “These patients are often critically ill, and the ability to manage the airway, blood pressure, and raised intracranial pressure among other issues can only improve patient management.” At the first annual society of vascular and interventional neurology (SVIN) meeting in Boston, Walter Koroshetz, deputy director of the National Institute of Neurological Disorders and Stroke, addressed the question, “Why the neurologist?” He emphasized that a vascular or neurocritical care background is an essential aspect of training, as this is the expertise the neurologist contributes to a field with neuroradiologists and neurosurgeons.[4]

  Neurosurgeons Top

It is easier for the neurosurgeon to attain rapid evolving learning curve in the endovascular procedures, because he is already knowing the gross appearance of vessels and the vascular lesions, which will improve the general orientation of the interventionist and have a profound implication of the patient safety during treatment, that is to say “mastering the knife as well as the catheter,”[16] because open surgical procedures are still the immediate and definite treatment. The main drawbacks for the open surgery option are the learning curve required, the risk of surgery, and the inoperable cases.

Intraprocedural arterial perforation (IPAP) is a potentially dismal complication of neuroendovascular therapy with high mortality and morbidity rates. IPAP can be rescued successfully with an aggressive approach and quick conversion to backup surgery by a dual-trained endovascular neurosurgeon in the hybrid operating room (OR).[17]

The challenge for neurosurgery in comparison to other specialties in regard to the care of patients with cerebrovascular disease is, in many ways, analogous to the challenge from orthopedic surgery in regard to the treatment of patients with spine disease. Although significant differences exist between the two situations, they are similar enough that the neurosurgical response to the orthopedic challenge can be used as a starting point for the neurosurgical response to the challenge of other specialties using endovascular therapy in the treatment of cerebrovascular diseases.[10]

  Patient’s Perspectives Top

When viewed from a patient’s perspective, he/she may simply enquire as to who would be the best to treat the vascular malformation in the brain and what are the internationally approved guidelines? The answer would be quite strange if you know the following current facts: (1) The endovascular management regimes are developing out of proportion to the time required to update the guidelines. (2) The increasing number of cases that were previously untreated via endovascular procedures and are currently considered one of the best indications for endovascular intervention (e.g., the basilar artery aneurysm). (3) The cost: for the endovascular coiling of cerebral aneurysm as an example, the cost usually depends on the number of catheters and coils being used during the procedure. Studies showed a relatively higher cost of admission for endovascular coiling as compared to open surgery with regard to a comparable cerebral aneurysm. Therefore, endovascular intervention is not always very cost effective as compared to open surgery.

Patient’s preference is one of the used indications for endovascular interventions offered by non-neurosurgeons; actually, it is a subjective matter and depends on the way the treatment options are presented to the patient.

  Discussion and Conclusion Top

There are a number of subspecialists, often situated in separate departments, including neurology, neurosurgery, and neuroradiology, who care for these patients and have overlapping skill sets.[18]

Cox et al. stated that radiologists performed 51% of all intracranial procedures in 2013, down from 80% in 2000. However, neurosurgeons have made substantial inroads into neuroendovascular procedures, with their volume increasing from 10 to 33% from 2000 to 2013. The overall volume of neuroendovascular procedures rose steadily from 2000 to 2013 (triple).[19] Even the literatures dealing with the radiologist confessed that the neuroendovascular intervention as a specialty “is much closer to surgery than to radiology.”[12]

The possibility of trial and error during the endovascular procedures is increasing with the continuous introduction of a new coil, stent, or flow-diverter design. This is the reality faced during the daily practice of endovascular therapy and may affect the patient’s life as well.

The risk of treatment and possible complications for cerebral aneurysms or arteriovenous malformations (AVMs) are obviously lower for the endovascular procedures as compared to open surgery. However, if the possibility of incomplete obliteration of the vascular lesions, multiple-staged procedures, recurrences, or coils impaction is taken in consideration, then there is a remarkable increasing risk of rebleeding during that period. Rebleeding usually does not occur if open surgery is applied, because open surgery usually obtains immediate and definitive treatment for such lesions.

In 2016, both Fennell et al.[20] and Montanera[21] conducted different interesting studies regarding “Morbidity and mortality of patients with endovascularly treated intracerebral aneurysms: does physician specialty matter?” In both studies, there was a statistically significant finding that neurosurgically trained physicians may demonstrate improved outcomes with respect to the endovascular treatment of unruptured aneurysms regarding both mortality and morbidity as compared with neurologists or radiologists.

Another issue is the recent increase in the number and complexity of INR procedures, which result in increased radiation exposure for the patient. Moreover, the extent of radiation exposure should be one outcome measure used to assess new technologies and procedural efficacy, and training programs should include techniques for exposure limitation.[22]

The highest training standard should be applied to physicians interested in performing any neurovascular intervention, because procedural complications can be disabling or fatal.[23] Thus, “the solitary practice of interventional neuroradiology is strongly discouraged.”[24] No specialist shall be excluded from practicing INR as long as they have been properly trained, because, thereby, it will lead to the best service being provided to the patients who trust us.[13]

Therefore, the solution for all specialties to be the best and, most importantly, the safest one to perform neuroendovascular procedures is to obtain enough training in all the requirements, “due to the grave consequences of inadequate or deficient training.”[24]

The most critical issue is when to quit the procedure and change to open surgery? We think that is the most important setting related to patient’s safety, because non-neurosurgeons have the tendency to stage procedures rather than shifting to open surgery. This will result in variations in decision and affect the patient’s safety, primarily because of the urgency of the current status.

A multispecialty team is logically the best choice to solve such conflict. However, in real life, it is quite hard to proceed the treatment decisions with ease unless there is a team head who will be able to take the final decision when there is numerous varying opinions.

Our recommendation is that the treatment of vascular lesions affecting the CNS must be offered either by a vascular team (open and endovascular) led by a neurosurgeon or by a dual neurosurgeon (a neurosurgeon how can perform both open surgery and endovascular intervention). By this, we can maximize the patient’s safety during the management of such lesions.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Available from: http://www.acgme.org/acWebsite/downloads/RRC_prRev/163_422pr08_31_06.pdf. [Last accessed on Sep 19, 2017].  Back to cited text no. 1
Doby T. Cerebral angiography and Egas Moniz. Am J Roentgenol 1992;159:364.  Back to cited text no. 2
Ligon BL. The mystery of angiography and the “unawarded” Nobel Prize: Egas Moniz and Hans Christian Jacobaeus. Neurosurgery 1998;43:602-11.  Back to cited text no. 3
Chen M, Nguyen T. Emerging subspecialties in neurology: Endovascular surgical neuroradiology. Neurology 2008;70:e21-4.  Back to cited text no. 4
Qureshi AI. Endovascular treatment of cerebrovascular diseases and intracranial neoplasms. Lancet 2004;363:804-13.  Back to cited text no. 5
Mazur MD, Taussky P, Park MS, Couldwell WT. Contemporary endovascular and open aneurysm treatment in the era of flow diversion. J Neurol Neurosurg Psychiatry 2018;89:277–286. doi: 10.1136/jnnp-2016-314477.  Back to cited text no. 6
Couldwell WT, Liu JK, Amini A, Kan P. Submandibular-infratemporal interpositional carotid artery bypass for cranial base tumors and giant aneurysms. Neurosurgery 2006;59:ONS353-9. Discussion ON S59-60.  Back to cited text no. 7
Sanai N, Zador Z, Lawton MT. Bypass surgery for complex brain aneurysms: An assessment of intracranial-intracranial bypass. Neurosurgery 2009;65:670-83. Discussion 83.  Back to cited text no. 8
Sekhar LN, Kalavakonda C. Cerebral revascularization for aneurysms and tumors. Neurosurgery 2002;50:321-31.  Back to cited text no. 9
Harbaugh R, Agarwal A. Training residents in endovascular neurosurgery. Neurosurgery 2006; 59(Suppl 5):S3-277-81.  Back to cited text no. 10
Interventional radiology as a (sub) specialty: A word of caution. Cardiovasc Intervent Radiol 2017;40:1-2.  Back to cited text no. 11
Houdart E. Interventional neuroradiology is dead! Long live endovascular therapy! Intervent Neuroradiol 2005;11:5-6.  Back to cited text no. 12
Rodesch G, Picard L, Berenstein A, Biondi A, Bracard S, Choi IS et al. Interventional neuroradiology: A neuroscience sub-specialty? Intervent Neuroradiol 2013;19:521-8.  Back to cited text no. 13
Babiarz L, Trotter S, Viertel V, Nagy P, Lewin J, Yousem D. Neuroradiology critical findings lists: Survey of neuroradiology training programs. Am J Neuroradiol 2012;34:735-9.  Back to cited text no. 14
Edgell R, Alshekhlee A, Yavagal D, Vora N, Cruz-Flores S. Interventional neurology: A reborn subspecialty. J Neuroimaging 2010;22:319-23.  Back to cited text no. 15
Peschillo S, Delfini R. Endovascular neurosurgery in Europe and in Italy: What is in the future? World Neurosurg 2012;77:248-51.  Back to cited text no. 16
Tsuei YS, Liao CH, Lee CH, Liang YJ, Chen WH, Yang SF. Intraprocedural arterial perforation during neuroendovascular therapy: Preliminary result of a dual-trained endovascular neurosurgeon in the neurosurgical hybrid operating room. J Chin Med Assoc 2018;81:31-6.  Back to cited text no. 17
Williams J, Hodgson T, Goldenberg F, Lukas R. Trends in neurology fellowship training. Neuroimmunol Neuroinflamm 2017;4:65.  Back to cited text no. 18
Cox M, Levin D, Parker L, Rao V. Relative roles of radiologists and other physicians in percutaneous endovascular neurointerventions. J Am Coll Radiol 2015;12:1030-5.  Back to cited text no. 19
Fennell V, Martirosyan N, Palejwala S, Lemole G, Dumont T. Morbidity and mortality of patients with endovascularly treated intracerebral aneurysms: Does physician specialty matter? J Neurosurg 2016;124:13-7.  Back to cited text no. 20
Montanera W. Editorial. Does physician specialty matter? J Neurosurg 2016;124:7-8.  Back to cited text no. 21
Alexander M, Oliff M, Olorunsola O, Brus-Ramer M, Nickoloff E, Meyers P. Patient radiation exposure during diagnostic and therapeutic interventional neuroradiology procedures. J Neurointervent Surg 2009;2:6-10.  Back to cited text no. 22
Jansen O, Szikora I, Causin F, Brückmann H, Lobotesis K. Standards of practice in interventional neuroradiology. Neuroradiology 2017;59:541-4.  Back to cited text no. 23
Connors J, Sacks D, Furlan A, Selman WR, Russell EJ, Stieg PE et al. Training, competency, and credentialing standards for diagnostic cervicocerebral angiography, carotid stenting, and cerebrovascular intervention. J Vasc Intervent Radiol 2009;20:S292-301.  Back to cited text no. 24


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