OBJECTIVE:To describe the history of vascular and endovascular neurosurgery.METHODS:A literature research was conducted including historical events from 2000 bc to the twenty-first century ad, and a timetable was filled with information regarding the most representative historical landmarks regarding vascular and endovascular neurosurgery.RESULTS:Starting from approaches limited to the cervical carotid artery, vascular neurosurgery gained its way through the intracranial and finally endovascular space thanks to the introduction of both innovative and progressively less invasive procedures. With the invention of cerebral angiography in 1927, Egas Moniz paved the way for modern endovascular neurosurgery.CONCLUSIONS:Numerous pioneers have been described through this historical reconstruction. Their genius, effort, dedication, and passion brought a massive contribution to vascular and endovascular neurosurgery as we know it today.

The authors report on the histologic and immunohistochemical analyses of a cerebral aneurysm embolized with platinum coils and with the longest observation period. A 58-year-old woman presenting with subarachnoid hemorrhage due to ruptured basilar top aneurysm was treated with Guglielmi detachable coils (GDC) 22 years ago. She was the 15th case since the GDC was introduced. After she died of unrelated causes, an autopsy and thorough histologic examination were performed. Gross examination revealed no adhesion between the aneurysm wall and the surrounding brain tissue. Histologic and immunohistochemical analyses demonstrated that the cavity of the aneurysm was filled with homogeneous collagenous fibrous tissue, while the neck was completely covered by a dense collagenous neointima and a smooth muscle cell layer. The unique histologic results of this case may contribute to a better understanding of the long-term evolution of the healing process in intracranial aneurysms successfully treated with the GDC.

During the last 10 years, the development of flexible microcatheters which can navigate cerebral vessels to lesions deep within the brain, has allowed the treatment of an increasing range of intracranial pathologies, including aneurysms. Techniques to embolize aneurysms, either by occlusion of their parent artery or endosaccular packing with its preservation, have evolved largely in order to treat inoperable aneurysms. Endosaccular packing with thrombogenic coils has recently allowed embolization of smaller aneurysms to be performed in patients acutely ill after subarachnoid haemorrhage. The procedural morbidity associated with these endovascular treatments are less dependent on aneurysm site than conventional neurosurgical clipping and initial results are comparable. These developments are challenging current thinking on the surgical management of patients with intracranial aneurysms. This review describes the evolution and practice of current endovascular treatments and their possible implications for the future of neuroradiology.

In the March 2014 issue of J Neurointerv Surg , I read an article entitled ‘A history of detachable coils: 1987–2012’,1 in which the progressive development of detachable coils over the past 25 years was described. The article was interesting and gave the reader a sense of how, starting from a basic ‘game changer’ idea,2–6 events progressed in a steady fashion over time, in an effort to offer the best possible treatment to patients harboring brain aneurysms. However, on page 1 of the article, in the paragraph entitled ‘The first coil’, there are some comments, statements, and information that need to be corrected. 1. As the inventor of the detachable coils (which is rightfully acknowledged by the authors), I was the first to test them.3 ,4 As such, I can state that the title of the article is incorrect and, for the sake of historical accuracy, should be changed to ‘A history of detachable coils: 1989–2012’. In other words, the ‘beginnings’ occurred in 1989 (not in …

In the July 2013 issue of the American Journal of Neuroradiology an editorial appeared, authored by Dr H.J. Cloft, entitled “Capitalism and Commodities: My Two Cents.”[1][1] In the editorial, Dr Cloft explains that nowadays “more that 20 years after the invention of the Guglielmi Detachable

The genesis of detachable coils and the background of this genesis are described in this article. To frame the beginning developmental stages of the discovery of detachable coils, the previous extravascular-intravascular and endovascular techniques are presented, as well as the development of the various delivery systems. The experimental studies, initial clinical application, and crucial moment of the conception of detachable coils are also reported.

The field of endovascular neurosurgery was paved by the work of a few creative “pioneers” who invented new delivery systems and new embolic agents capable of treating vascular diseases of the brain, such as aneurysms. Knowledge of the historical basis, of the foundations, of our discipline is always beneficial: it allows appreciation of the work of the “fathers” and gives a sense of continuity in science. It also gives doctors in training the fundamental background information. And, why not, history is also entertaining! The history of the endovascular treatment of brain aneurysms can be divided into three periods or eras: the pre-balloons era, the balloons era and the coils era. We can say that, as of today (2009), our discipline of endovascular neurosurgery–interventional neuroradiology is 45 years old! In fact, Luessenhop and Velasquez performed the first catheterization of intracranial vessels in 1964.1 They invented a system capable of entering brain arteries with a silastic microcatheter, via the surgically exposed external carotid artery in the neck. They even performed endovascular temporary balloon occlusion of the neck of a posterior communicating artery aneurysm. They prophetically predicted that “catheterization as well as embolization of the intracranial arteries may have therapeutic usefulness, particularly in the treatment of aneurysms and arteriovenous malformations”. In the mid-1960s, Frei, Yodh, Driller, Montgomery, Cares and Hilal utilized a new microcatheter called para-operational device (POD).2 3 4 5 6 7 The proximal portion was made of polyethylene and the distal portion of soft silicone rubber. The distal section measured only 1.3 mm in outer diameter and was 7 cm in length. Embedded in the tip of the silicone tubing was a micromagnet which measured 1 mm in diameter. External magnetic fields, both continuous and alternating, could be applied to pull and bend the micromagnet tipped microcatheter (by the continuous field) and …

OBJECTA series of 306 consecutive patients with an anterior communicating artery (ACoA) aneurysm is presented. The goal in this study was to report the results of endovascular treatment of ACoA aneurysms in these patients.METHODSThe aneurysms were managed with an endovascular approach in which detachable coils were used. A brief anatomical description of the ACoA and its branches as well as a review of the surgical and endovascular literature is presented. The "ACoA Syndrome" (that is, amnesia and personality changes), which may occur after subarachnoid hemorrhage, is briefly reviewed and described. Recent technical developments that can lead to improved results are also discussed.RESULTSOf the 306 aneurysms, 268 (87.5%) were small, 30 (10%) were large, and 8 (2.6%) were giant. One hundred ninety-three aneurysms (63%) had a small neck, whereas 113 (37%) had a wide neck. Sixty-five lesions (21%) were incidental, 5 (2%) presented with symptoms of mass effect, and 236 (77%) presented with a subarachnoid hemorrhage. A complete aneurysm occlusion was attained in 139 cases (45.5%), a neck remnant was detected in 145 (47.5%), and in 22 cases (7%) a residual filling of the aneurysm was observed. Regarding the clinical neurological outcome, 280 patients (91.5%) remained neurologically intact, improved, or unchanged from their initial clinical status. Two large, wide-necked, subtotally occluded aneurysms ruptured 3-7 months after the procedure, with subsequent death of the patients. The procedure-related morbidity and mortality rates were 3.5% (11 cases) and 1% (3 cases), respectively.CONCLUSIONSThe inherently lower risk of injuring or occluding the delicate branches and perforating vessels arising from the ACoA makes the endovascular approach attractive, interesting, and elegant.

The endovascular approach is described in 113 middle cerebral artery (MCA) aneurysms. The treatment failed in six cases with no adverse clinical consequences. Out of the 107 treated cases, it was possible to obtain a complete occlusion in 50 aneurysms (47%), whereas a residual aneurysm neck was observed in 54 cases (50%). Follow-up angiograms were performed in 60 cases, showing a 22% rate of further thrombosis of the aneurysm. Recanalization of the aneurysm was observed in 8% of cases, which required retreatment.The technique-related permanent morbidity rate was 9% while the mortality rate was 2%. A review of the surgical and endovascular literature is presented. The endovascular approach is particularly indicated when normal MCA branches do not arise from the aneurysm base. It must be meticulously planned in all other cases. Endovascular coil treatment of MCA aneurysms is feasible, with acceptable morbi-mortality rates.

The endovascular approach is described in 113 middle cerebral artery (MCA) aneurysms. The treatment failed in six cases with no adverse clinical consequences. Out of the 107 treated cases, it was possible to obtain a complete occlusion in 50 aneurysms (47%), whereas a residual aneurysm neck was observed in 54 cases (50%). Follow-up angiograms were performed in 60 cases, showing a 22% rate of further thrombosis of the aneurysm. Recanalization of the aneurysm was observed in 8% of cases, which required retreatment. The technique-related permanent morbidity rate was 9% while the mortality rate was 2%. A review of the surgical and endovascular literature is presented. The endovascular approach is particularly indicated when normal MCA branches do not arise from the aneurysm base. It must be meticulously planned in all other cases. Endovascular coil treatment of MCA aneurysms is feasible, with acceptable morbi-mortality rates.

In order to overcome the possibility of recanalization and compaction with Platinum GDC coils Tantalum coils were placed in three aneurysms in swine. Comparative coiling was done on the other side in each animal with platinum GDC.More stable thrombus was observed on the aneurysms coiled with Tantalum GDC.

OBJECTIVE: The goal of this report is to analyze the hemodynamic characteristics of low- and high-flow arteriovenous malformations (AVM) using computerized electrical models.METHODS: Two electrical models of brain AVMs were created. These models consist of electrical resistors that Simulate AVM vessels. In both models, a low-flow AVM and a high-flow AVM, the flow of electrons simulates the flow of blood.RESULTS: Using the models, it was possible to analyze the pressure and flow patterns in the nidus of the small, low-flow AVM and in the nidus of the large, high-flow AVM. Baseline hemodynamic "physiological" conditions of the two AVMs were studied. With the models, it was also possible to assess the AVM hemodynamic changes (in the feeding arteries, in the various parts of the nidus, and in the draining veins) after surgery, after embolization, and after surgical bypass of the malformation. The role of autoregulation in the three treatment modalities was also assessed.CONCLUSION: These electrical models seem to be useful in simulating and studying the behavior of flow and pressure in the different parts of the AVM nidus (arterial, arteriolar, arteriolar-venular, venular, venous) before and after treatment. The models can also be used to devise and simulate new treatment strategies that might lead to improved treatment of these highly complex vascular malformations of the brain.

To the Editor: I attentively read the “Endovascular Neurosurgery” supplement to the November 2006 issue of NEUROSURGERY. Regarding the endovascular treatment of brain aneurysms with the Guglielmi detachable coiling (GDC) technique, I noticed that in two reports (2,3) the role of electrothrombosis was considered to be null. I would like to clarify that effective electrothrombosis did not even come close to the GDC technique. In fact, the amount of electricity that was delivered (1 mA) was not enough to generate a sufficient electrothrombotic phenomenon. The mass of the thrombus is directly proportional to the amount of electrical current. Chen, Ji, and Guglielmi performed a series of in vitro experiments on heparinized blood (unpublished data). They confirmed that the amount of thrombus is directly proportional to the electrical current. The following weights of thrombus were formed when the given current was applied for 3 minutes, using a platinum electrode: at 1 mA, mass was 10 mg; at 2 mA, mass was 12 mg; at 3 mA, mass was 26 mg; and at 10 mA, mass was 85 mg. Past researchers (1) have almost always used 10 mA to produce sufficient electrothrombosis in both the experimental and clinical settings. From the data of the literature, we can say that when applying 1 mA of current, the mass of the (electro)thrombus is almost insignificant. Despite the reassuring experimental and clinical data of the literature, we did not increase the electrical current from 1 to 10 mA. Whether an increase of the electrical current would lead to improved results remains unknown. Guido Guglielmi Rome, Italy

Four cases of posterior cerebral artery (PCA) aneurysms are described. The aneurysms were located at the P2 segment of PCA. All cases presented with a subarachnoid hemorrhage (SAH). Endovascular treatment was performed, with occlusion of the aneurysm and parent vessel, using platinum coils. Two patients developed a homonymus lateral hemianopia after treatment.

OBJECTIVE: Peripheral brain aneurysms arise from the distal segments of cerebral arteries. They can be treated by surgery or by an endovascular approach. We present our experience of endovascular treatment of peripheral brain aneurysms with a novel enclovascular device, the Guglielmi detachable coil (GDC) "crescent."METHODS: The GDC "crescent" is a 5-mm long, curved coil steerable beyond the tip of a microcatheter and detachable at a distance. The GDC "crescent" was used in three cases of intracranial peripheral aneurysms to occlude their parent vessel.RESULTS:Three peripheral brain aneurysms in three patients were successfully treated with parent vessel occlusion using the prototype GDC "crescent" coils, thereby excluding the aneurysms from the brain circulation. No complications were encountered.CONCLUSION: From this limited experience, the GDC "crescent" seems particularly suitable for the controlled endovascular occlusion of the often-narrow parent artery of distal brain aneurysms.

A concise historical review of the endovascular, endosaccular treatment of intracranial aneurysms is reported. The transition from detachable balloons to detachable coils is described. The development of microcatheters for intracranial endovascular navigation is also reported.