[Analysis of intracranial saccular aneurysm wall: neuroimaging and histopathological correlates]. / Issledovanie stenki intrakranial'nykh meshotchatykh anevrizm: neirovizualizatsionnye i gistopatologicheskie korrelyaty.

BACKGROUND: Contrast enhancement of intracranial aneurysm wall during MRI with targeted visualization of vascular wall correlates with previous aneurysm rupture and, according to some data, may be a predictor of further rupture of unruptured aneurysms. OBJECTIVE: To analyze possible causes of aneurysm contrast enhancement considering morphological data of aneurysm walls. MATERIAL AND METHODS: The study included 44 patients with intracranial aneurysms who underwent preoperative MRI between November 2020 and September 2022. Each aneurysm was assessed regarding contrast enhancement pattern. Microsurgical treatment of aneurysm was accompanied by resection of its wall for subsequent histological and immunohistochemical analysis regarding thrombosis, inflammation and neovascularization. Specimens were subjected to histological and immunochemical analysis. Immunohistochemical analysis was valuable to estimate inflammatory markers CD68 and CD3, as well as neurovascularization marker SD31. RESULTS: Aneurysms with contrast-enhanced walls were characterized by higher number of CD3+, CD68+, CD31+ cells and parietal clots. Intensity of contrast enhancement correlated with aneurysm wall abnormalities. CONCLUSION: Contrast enhancement of aneurysm wall can characterize various morphological abnormalities.

[Pathological tortuosity of intracranial arteries (pure arterial malformation) - diagnosis and management tactics]. / Patologicheskaya izvitost' intrakranial'nykh arterii (arterial'naya mal'formatsiya) ­ diagnostika i taktika vedeniya.

BACKGROUND: Tortuosity of intracranial arteries is rare and usually mistaken for arteriovenous malformations. In the world literature, the term «pure arterial malformations¼ is used to refer to this disease. OBJECTIVE: To summarize the experience of the Burdenko Neurosurgery Center on diagnosis of intracranial artery tortuosity, management and treatment of these patients, as well as to review appropriate literature data. MATERIAL AND METHODS: Tortuosity of intracranial arteries was detected in 11 patients (8 women and 3 men) aged 7-48 years who underwent outpatient or inpatient examination and treatment at the Burdenko Neurosurgery Center between 2009 and 2022. We analyzed angiographic, clinical and follow-up data of these patients, as well as appropriate literature data. RESULTS: According to angiography data, all patients had moderate dilatation, elongation and tortuosity of intracranial arteries without signs of arteriovenous shunting. The most common finding was tortuosity of several segments of internal carotid artery (5 cases). Lesion of PCA, PComA, MCA and ACA was less common. In 7 cases, the walls of the deformed vessels had calcified zones. In two cases, there were saccular aneurysms in the walls of the tortuous vessels. In one case, tortuosity was combined with kinking of the left subclavian artery, in another one - tortuosity of C1 segment of the right ICA. No patient had specific clinical manifestations. The follow-up period was 1-10 years in 7 patients. There were no changes in structure of tortuosity or appearance of new aneurysms. CONCLUSION: Tortuosity of intracranial arteries is an extremely rare disease with the highest incidence in young women. This abnormality has no specific clinical manifestations and does not require surgical or conservative treatment. Tortuosity of intracranial arteries should be differentiated from arterial dolichoectasia, fusiform aneurysms and AVMs.

[Magnetic resonance imaging of saccular intracranial aneurysm wall]. / MR-vizualizatsiya sosudistoi stenki meshotchatykh intrakranial'nykh anevrizm.

BACKGROUND: Hemorrhage from intracranial aneurysms is associated with high risk of adverse outcomes. In this regard, surgical treatment of unruptured asymptomatic aneurysms has been actively developed in recent decades. One of the objectives is searching for predictors of aneurysm rupture to clarify the indications for surgery. Non-invasive analysis of vascular wall is actively discussed in last years. OBJECTIVE: To evaluate the possibilities of MRI of ruptured and unruptured intracranial aneurysm walls and determine clinical significance of certain morphological patterns. MATERIAL AND METHODS: The study included 111 patients with 158 ruptured and unruptured saccular aneurysms who underwent MRI according to a special protocol between November 2020 and September 2023. We analyzed each aneurysm regarding features of contrast enhancement and changes in SWAN images. After that, we compared these data with ruptures. RESULTS: Wall of ruptured and unruptured aneurysms can accumulate contrast agent. We found 5 types of contrast enhancement. Thick-layer contrast enhancement was accompanied by 9.6-fold higher risk of aneurysm rupture compared to aneurysms without contrast enhancement. Dark MR signal from intracranial aneurysm wall in SWAN imaging is a significant sign of rupture. CONCLUSION: MRI of the vascular wall is valuable to verify ruptured aneurysms. Unruptured aneurysms can accumulate contrast agent inside the wall, and pattern of accumulation differs from ruptured aneurysms. Morphological analysis is needed to confirm contrast enhancement as a marker of aneurysm rupture.

[Surgical treatment of patients with cerebral aneurysms in the acute stage of rupture: dynamics of results during 2006-2018]. / Khirurgicheskoe lechenie bol'nykh s anevrizmami sosudov golovnogo mozga v ostroi stadii razryva: dinamika rezul'tatov za 2006-2018 gg.

Treatment of cerebral aneurysms in the acute stage of subarachnoid hemorrhage (SRH) especially on the background of cerebral vasospasm continues to be a difficult task. OBJECTIVE: Assessment of dynamics of the surgical treatment results of patients with cerebral aneurysms in acute period of SRH. MATERIAL AND METHODS: A comparative analysis of the results of patients' surgical treatment in NMRCN Burdenko about aneurysm in 1-21 days after hemorrhage was made. The following periods were selected: 2006-2014 (343 patients) and 2015-2018 (356 patients). Most patients had microsurgical operations in both periods. The tactics of choosing the surgery time was the main difference between the periods: particularly in 2015-2018 period the surgery was not postponed at patients with severe. RESULTS: Analysing the post surgical mortality, it was found that since 2006 there is a consistent trend towards a decrease in the number of patients who died after surgery. When calculating the average post surgical mortality for the studied periods this trend is confirmed - number of lethal cases in 2015-2018 reliably decreased when comparing with 2006-2014 - from 6.8 till 3.2%; p=0.03. At the same time, the number of patients with outcome of vegetative status (from 0.3 till 5%). CONCLUSION: The tactics of surgical treatment of patients with cerebral aneurysms in the acute period of SRH regardless of severity of patient's condition and time of hemorrhage did not lead to worse treatment. In contrast, post surgical mortality rates show a consistent decline. We associate this fact with a number of changes that have occurred in the management and treatment of patients. In particular, we have high hopes for developing new approaches to the treatment of vasospasm, which remains the leading cause of lethal cases. More definite conclusions will be made at the end of the treatment analysis of the respective patient groups.

[Intra-arterial administration of verapamil for prevention and treatment of cerebral angiospasm after SAH due to cerebral aneurysm rupture]. / Intraarterial'noe vvedenie verapamila dlia profilaktiki i lecheniia tserebral'nogo angiospazma posle SAK vsledstvie razryva anevrizm sosudov golovnogo mozga.

AIM: The study purpose was to analyze the efficacy of intra-arterial administration of verapamil (IAV) in the treatment of angiospasm in SAH patients and to determine optimal parameters of the procedure. A number of studies demonstrated the efficacy of intra-arterial administration of vasodilators, in particular verapamil, in the treatment of angiospasm after aneurysmal SAH, which served the basis for inclusion of this method in the recommended protocol for treatment of SAH patients [1-7]. MATERIAL AND METHODS: We analyzed the efficacy of IAV in 35 patients in the acute period of SAH, with 77.2% of the patients having a Hunt-Hess score of III-V. The inclusion criteria were as follows: IAV within two weeks after SAH; excluded aneurysm; verapamil dose per administration of at least 15 mg; follow-up for at least three months. Efficacy endpoints were as follows: changes in spasm according to angiography and transcranial dopplerography (TCDG); development of ischemic lesions; clinical outcome according to the modified Rankin scale. RESULTS: A total of 76 IAV procedures were performed. The verapamil dose per procedure was 36.7±9.7 mg, on average; the number of procedures varied from 1 to 5. One arterial territory was treated in 12 cases, two arterial territories were treated in 48 cases, and three arterial territories were treated in 15 cases. Typical adverse reactions included decreased blood pressure, a reduced heart rate, and elevated ICP. In all cases, TCDG revealed signs of reduced angiospasm - a 20-40% decrease in the LBFV in the M1 MCA. Four (11.4%) patients died; of these, only one died due to angiospasm progression. On examination at 3 months or more after discharge, favorable outcomes were observed in 74.3% of cases. CONCLUSION: IAV is associated with a low risk of significant complications. IAV should be performed under control of systemic hemodynamics and ICP. The indications for IAV include signs of moderate worsening or severe angiospasm according to TCDG and/or angiography. The IAV procedure may be performed every day. Further clarification of the IAV procedure and evaluation of clinical outcomes under prospective study conditions are required.

[Surgical treatment of a pregnant female with AVM hemorrhage]. / Khirurgicheskoe lechenie patsientki s krovoizliyaniem iz AVM vo vremya beremennosti.

Hemorrhages from arteriovenous malformations (AVMs) in pregnant females are rare, but they are known to lead to high maternal and infant mortality. There are no standards for AVM treatment in pregnant females. Many authors believe that AVM resection before delivery improves the prognosis for life and health of the mother and fetus. In this paper, we present a case of successful surgical treatment of a female patient with AVM hemorrhage at 20 weeks and address management issues of these patients.

[De novo cerebral aneurysms].

OBJECTIVE: To substantiate the reasonability and duration of angiographic follow-up of patients operated on for cerebral aneurysms to rule out de novo aneurysm formation. MATERIAL AND METHODS: The results of angiographic examination (cerebral angiography and SCT angiography) of 43 patients with cerebral aneurysms operated on at the Burdenko Neurosurgical Institute in 1995-2012 are analyzed. The follow-up duration varied from 1 to 14 years after surgery (mean duration, 5 years). Patients' age ranged from 14 to 56 years. RESULTS: Control angiographic examination showed that de novo aneurysms were formed in 7 (16.2%) patients. A total of 8 de novo aneurysms were detected (in one case there were two aneurysms formed). All aneurysms, both the previously operated and the de novo ones, were located in the anterior part of the circle of Willis. De novo aneurysms were clipped in 5 cases; the cavity of the de novo aneurysm was occluded with spirals in one case. One patient with a small aneurysm of the middle cerebral artery refused surgery. Neither lethal nor unfavorable outcomes were recorded. CONCLUSIONS: The patient groups with the high risk of de novo aneurysm formation are as follows: 1) young smokers with hypertension; 2) patients who developed clinical signs of the disease when being young; 3) patients subjected to proximal exclusion of the main artery; and 4) patients with multiple and familial forms of the pathology. Dynamic angiographic follow-up (SCT angiography or magnetic resonance angiography) for 1-3 years is recommended for these patients.

[Intraoperative indocyanine green fluorescence angiography in surgery of brain aneurysms. The first experience with using the technique and literature review].

Intraoperative blood flow assessment after aneurysm clipping has become a standard procedure in vascular neurosurgery worldwide. Intraoperative indacyanine green angiography (ICG) has recently been certified in Russia. Fifteen patients with aneurysms operated with ICG control in Burdenko NSI are described in present publication. ICG advantages and weaknesses are discussed along with alternative flow control techniques available now.

[Long-term results of treatment of patients with large or giant intracranial aneurysms of internal carotid artery].

At Burdenko Neurosurgical Institute annually arrives 50-60 patients with large and giant aneurysms of the brain, which is nearly 15% of all patients with aneurysms. About half of them--patients with paraclinoid aneurysms, which are successfully treated by cliping using techniques of intravascular blood aspiration (IVBA) or proximal control of blood flow in the neck. This paper analyzes the long-term outcomes of patients who were operated for large and giant aneurysms of the internal carotid artery in the last 15 years. Catamnesis was collected from 93 (71.5%) of 130 patient. Mean follow-up was 65.2 +/- 36.0 months. Mean age of patients at the time of surgery was 45.55 +/- 7.5 years and at the time of catamnesis evaluation 50.4 +/- 10.2 years. Men to women ratio was 18:75. Patients with multiple aneurysms was 22.6% (21 patients). In most cases--67 (72%) patients--aneurysms were treated by cliping of aneurysms using IVBA, in 14 (15%) cases--using proximal control of blood flow in the neck, in 5 (5.4%) cases--reinforced with gauze and glue, in 6 (6.5%) patient--by aneurysm trapping, in one case the aneurysm was not cliped. Radical surgery performed in 87 (93.5%) patients. Catamnesis analysis of survived patients showed that 55.8% of them are complaining of headaches, which they associate with the operation. 39 (43.3%) patients noted persistent elements of asthenia, 4 (4.6%) had sleep disorders, 5 (5.8%) suffered of epileptic seizures and 1 (1.10%) of depression. Korsakoff's syndrome, developed after surgery in 2 (2.3%) patients remains. Only 38.4% of patients after surgery continue to work. Favorable outcome on the Glasgow outcome scale (4-5) was obtained in 81 (87.1%) patients, poor (2-3) in 5 (5.4%) patients. Mortality rate was 7.5%. Severe oculomotor disturbances have a slight tendency to recovery over time.

[Diagnosis of the source of bleeding in multiple cerebral aneurysms by susceptibility-weighted imaging].

OBJECTIVE: to evaluate the efficiency of susceptibility-weighted imaging (SWI) in diagnosing the source of bleeding in multiple cerebral aneurysms. SUBJECTS AND METHODS: This investigation enrolled 30 patients with multiple aneurysms (MA) treated at the N. N. Burdenko Neurosurgery Research Institute in 2008 to 2011. A study group included 19 women and 11 men whose age was 28 to 62 years. Thirty patients with MA were found to have 84 aneurysms at different sites. All the 30 patients were operated on using microsurgical techniques. RESULTS: SWI established the source of bleeding in 27 of the 30 patients. The technique was informative in all the cases, except 2 patients, who were studied in late periods (3 and 16 years) after hemorrhage. Bleeding in one patient with MA and suspected clinical subarachnoid hemorrhage was not confirmed by SWI or during surgery. According to the authors' data, the sensitivity and specificity of the technique were 93.1 and 100%, respectively. CONCLUSION: SWI is the method of identifying the source of bleeding in patients with MA, which enables the treatment tactic to be correctly chosen. The informative value of the technique decreases as a longer period is after hemorrhage.

[Stepwise treatment of multiple cerebral aneurysms utilizing surgical and endovascular techniques].

To evaluate results of combined treatment of multiple intracranial aneurysms utilizing microsurgical clipping with endovascular techniques. Study group comprised 60 patients with 230 multiple aneurysms (MA) of different location. Most common were aneurysms of ICA--49% and MCA--24%. Single-side ICA aneurysms were found in 11 (18.3%) patients, two-sides ICA lesions in 25 (41.7%); single-side ICA aneurysm with posterior circulation aneurysm--11 (18.3%) and two-sides ICA aneurysm with posterior circulation aneurysm in 13 (21.7%). All patients were treated with endovascular coiling followed by direct surgery. Eight patients treated in acute stage of SAH. Two-stage surgery was performed in 49 cases, three-stage treatment--in 11 cases yielding 131 operations total. Time break between surgeries was 1 day to 4 month. Total occlusion was achieved in 95.3% cases, 98 aneurysms were clipped, 64 (33.4%) coiled. In 15 (7.8%) patients aneurysms were excluded with stent or balloon assisting techniques. Six aneurysms were treated with flow diverters (Pipeline Embolisation Device). Palliative treatment (ICA occlusion with balloon or coils and aneuryms wrapping) were performed in 4.7%. There were no fatal outcomes or complications required repeated surgery in the group. Multimodal approach that combines endovascular techniques with microsurgery is an effective option in multiple aneurysm treatment. Updated endovascular modalities and direct surgery together become a treatment of choice for MA patient improving radical exclusion rate and outcomes. Combined treatment is specifically indicated for elaborate MA cases requiring multiple approaches.

[Complex intracranial vascular pathology: multiple aneurysms combined with ICA aplasia].

Rare case of multiple aneurysms of posterior circulation associated with right ICA aplasia in 39 year old female patient is described. Detailed description of ICA aplasia is enclosed. Modern diagnostic methods (MRI-SWI) were performed to identify the bleeding source. Ruptured PCA aneurysm was successfully treated with clipping. The case carries clinical interest from the standpoint of rarity and management.

[Microsurgical treatment of cerebral arteriovenous malformations in Burdenko Neurosurgical Institute (recent experience)].

Recently the number of AVM resections in Burdenko Neurosurgical Institute has been increased dramatically. Aim of this study was to assess the results of open surgery in our clinic in modern neurosurgical era. Consecutive series if 160 patients with AVM treated using microsurgical technique since 2009 till 2011 was analyzed. Spetzler-Martin score distribution was: grade I--29 (18.1%) cases, grade II--84 (52.5%), grade III--38 (23.8%), grade IV--9 (5.6%). Patients with grade V AVMs were not operated. Treatment options included: AVM resection in 143 (89.4%) cases, embolization followed by resection in 15 (9.3%) and clipping of afferents in 2 (1.3%). Glasgow outcome scale score distribution was the following: V (good recovery)--70 (43.7%), IV (moderate disability)--71 (44.4%), III (severe disability)--16 (10%), II (vegetative state)--1 (0.6%) and I (death)--2 (1.3%). Microsurgery remains the primary option for radical treatment of cerebral AVMs. Careful selection of patients and planning of surgery are crucial for good outcomes.

[Substantiation of differentiated management of patients with multiple cerebral aneurysms].

The study was performed to substantiate optimal tactics of management of patients with multiple cerebral aneurysms based on analysis of surgical results. This study included 233 (20%) patients with multiple cerebral aneurysms who were treated in Burdenko Neurosurgical Institute since 1995 till 2007. We analyzed results of single-stage (microsurgical technique) and multistage (microsurgical technique and step-by-step application of endovascular and microsurgical techniques) approaches. The following factors were investigated: severity of subarachnoid hemorrhage (Hunt-Hess scale), localization of aneurysms in different arterial systems, quantity and size of aneurysms.. Postoperative mortality was 4.7%. Poor outcomes were observed in 37 (16%) patients. In multi-stage surgical treatment the number of totally occluded aneurysms was significantly higher (92% vs. 79%, p < 0.05) as the number of palliative operations and untreated aneurysms was lower (5.8% vs. 16%, p < 0.05). The best technical and clinical results were obtained in the group of patients who were treated using step-by-step application of endovascular and microsurgical techniques. Despite coexistence of aneurysms of both carotid systems with vertebrobasilar aneurysms in 15% of this group, poor outcomes were not observed and total occlusion of aneurysms was performed in 91.4% of cases. Obtained technical and clinical results of treatment of multiple aneurysms prove that multi-stage surgical management is the therapy of choice in surgery of multiple aneurysms. Our data demonstrate high effectiveness of multimodal approach with integration of endovascular and microsurgical methods. Combination of both techniques is preferential in coexistence of aneurysms of carotid and vertebrobasilar systems.

[Local fibrinolysis in treatment of non-traumatic intracerebral hematomas and ventricular hemorrhages].

Local fibrinolysis and aspiration in treatment of spontaneous intracerebral hematomas (SIH) and ventricular hemorrhages (VH) have become a wide spread technique in dedicated cerebrovascular centers. Forty four patients treated in Burdenko NSI in 2007-2011 were evaluated. Local fibrinolysis for SIH were perfomed in 30 pt., for isolated VH in 14. Puroplazan, a prourokinaze based derivative (mean dose - 50 000 ME) were used in 36 cases, Actilyse (tPA) (2.0 g mean) in 8 cases. Status at discharge was improved in 66.7% of patients with SIH and 57.1% of patients with isolated VH. Mortality comprised to 10 and 28.6% correspondingly. Local hematoma aspiration and fibrinolysis is an effective minimally-invasive method of primary and secondary non-traumatic SIH and VH evacuation. Dose of fibrinolytic agent should be selected individually and depends on hematoma volume. Applied dose clinically-wise should be decreased along with reducing of hematoma size and number of injections to minimize recurrent hemorrhage risk.

[The role of susceptibility-weighted MRI in detection of ruptured aneurysm in multiple aneurysms].

Since 2008 till 2010 years 22 patients with multiple aneurysms were examined in Burdenko Neurosurgical Institute (Moscow, Russia). The series included 13 female and 9 male patients, age ranged from 28 to 62 years (mean 45 years). 68 aneurysms of different localization were discovered in these 22 patients. We also analyzed results of examination of 2 patients with solitary aneurysms in which SW-MRI was performed to confirm or exclude the fact of hemorrhage due to rupture of the aneurysm. All patients were operated microsurgically. SW-MRI is effective technique for identification of source of hemorrhage in patients with multiple aneurysms thus allowing selection of correct tactics of management. Information value of the method declines with increase of time after hemorrhage (over 2 years). SW-MRI enables verification of the fact of hemorrhage due to aneurysm in disputable cases (minimal non-specific clinical presentation, absence of hemorrhage verification).

[Acute injuries to the upper gastrointestinal tract in patients with multiple cerebral arterial aneurysms].

The paper describes a case of multiple cerebral arterial aneurysms in a patient with prior subarachnoidal hemorrhage, who developed postoperative acute upper gastrointestinal tract (GIT) lesion manifesting itself as bleeding and requiring multiple endoscopic treatment procedures and eventually a direct surgical intervention. The susceptibility of patients with cerebral pathology to upper GIT lesions and methods of their therapy and prevention are discussed.

[Cognitive disturbances in patients with arteriovenous malformations, cerebellar cavernomas and hematomas].

A clinical-neuropsychological study using Luria's method has been conducted in 13 patients with arteriovenous malformations (AVM) and 12 patients with cerebellar cavernomas and hematomas. The syndromes were similar to lesions of the large hemisphere cortex, more often of premoter regions and less often of the cortex of posterior hemispheric regions. After a surgery on the right cerebellar hemisphere, some patients had perseverations and micrographia in writing. These syndromes were principal similar with findings described in the literature. However there were differences including the absence of marked cognitive disturbances even after the surgery. The disturbances of verbal memory were found in the lesion of both right and left cerebellar hemispheres that is the functional asymmetry of cerebellar hemispheres was not pronounced. The inactivity of speech and agrammatism in writing, even in patients with large duration of hemorrhage, were not observed. In some patients with the lesion of right cerebellar hemisphere, the disinhibition of speech, similar to that in patients with the lesion of right frontal lobe, was found. There were no marked mental disturbances. The most distinct cognitive disturbances were found after surgeries of the superior cerebellar artery. Possible mechanisms of the cerebellum's role in cognitive functions are discussed.

[Stage-by-stage treatment of multiple cerebral aneurysms using endovascular and microsurgical techniques].

Aim of the study was to substantiate effectiveness of stage-to-stage application of microsurgical and endovascular techniques in treatment of patients with multiple cerebral aneurysms (MA). 22 patients with MA were included in this study. 70 aneurysms of different location were found in this series. Aneurysms of MCA were the most frequent. Unilateral aneurysms were found in 6 patients, bilateral -- in 7, unilateral with aneurysm of vertebro-basilar system -- in 4, bilateral with aneurysm of vertebro-basilar system -- in 5. All 22 patients underwent surgical treatment with stage-to-stage application of endovascular and microsurgical techniques. 6 patients were operated in acute period of SAH. In 16 cases two-stage surgeries were made, in 5 -- three-stage. Totally 42 operations were performed. Intervals between stages varied from 1 day to 4 months. Total occlusion of aneurysms was achieved in 91.4% of cases. 40 aneurysms were clipped and 22 were coiled. In 2 cases aneurysms were occluded using coils and stent. Enforcement of aneurysmal walls by oxycellulose and different glue compositions was used in 4 cases. There was no mortality in the series. In 1 female patient with 6 aneurysms transient neurological deficit occurred after third stage of surgical treatment (stenting of basilar artery with coiling of aneurysm of this artery). We did not observe complications demanding wound revision. Obtained results of stage-to-stage surgical treatment of MA are the evidence of high effectiveness of multimodal approach with integration of endovascular and microsurgical techniques. This tactics allows to decrease mortality and disability in acute period of SAH as well in cold period. Described approach can be the treatment of choice in surgical management of MA.

[Microsurgical treatment of large and giant aneurysms of the internal carotid artery: analysis of application of intravascular blood aspiration technique and future perspectives].

The article discusses results of surgical treatment of 82 patients with large and giant cerebral aneurysms operated in Burdenko Neurosurgical Institute (Moscow, Russia) during the recent 14 years. Special attention was given to benefits of intravascular blood aspiration (IBA) technique. This technique was proven to be very effective, allowing to clip the aneurysm in 87.8% of cases with good recovery in 41.5% and with moderate disability in 39%. Postoperative mortality was 4.9% (4 patients). The authors suggested original surgical classification of large and giant aneurysms. IBA was ineffective in cases of giant partially thrombosed aneurysms with sclerotic walls and giant aneurysms with very wide neck. These aneurysms require other surgical procedures such as embolization of ICA followed by extraintracranial bypass or high-flow bypass.