[Mathematical modeling of high-flow extra-intracranial bypass in the treatment of a complex cerebral aneurysm]. / Matematicheskoe modelirovanie obkhodnogo vysokopotochnogo ekstra-intrakranial'nogo shuntirovaniya pri lechenii slozhnoi tserebral'noi anevrizmy.

BACKGROUND: Intracranial aneurysms (IAs) pose a high risk of spontaneous subarachnoid hemorrhage. In the most complex cases, the only way to exclude the aneurysm from the circulation is to perform a high-flow extracranial-to-intracranial bypass, thus creating a new bloodstream. This avoids severe ischemic complications; however, it requires careful consideration of individual anatomy and hemodynamic parameters. Computational fluid dynamics (CFD) can be of great help in planning such a surgery by creating 3D patient-specific models of cerebral circulation. OBJECTIVE: Assessment of the perspectivity of high-flow extracranial-to-intracranial bypass planning using computational modeling. MATERIAL AND METHODS: In this research work, we have applied the CFD methods to a patient with a giant thrombosed IA of the internal carotid artery (ICA). Preoperative CTA images and Gamma Multivox workstation were used to create a 3D model with current geometry and three additional models: Normal anatomy (no IA), Occlusion (with ligated ICA), Virtual bypass (with bypass and ligated ICA). The postoperative data were also available. Boundary conditions were based on PC-MRI measurements. Calculation of hemodynamics was conducted with a finite element package ANSYS Workbench 19. RESULTS: The results demonstrated an increase in the blood flow on the affected side by more than 70% after the virtual surgery and uniformity of flow distribution between the affected and contralateral sides, indicating that the treatment is likely to be efficient. Later, postoperative data confirmed that. CONCLUSION: The study showed that virtual preoperative CFD modeling could significantly simplify and improve surgical planning.

[Brain retraction injury]. / Retraktsionnaya travma golovnogo mozga.

This review is devoted to various techniques for reduction of brain damage during retraction. Searching for reports was carried out in Russian and English languages using the PubMed database (n=721) without restrictions on language, date and study design according to the following keywords: «brain retraction injury¼, «spatula brain retractors¼, «tubular brain retractors¼, «retractorless neurosurgery¼. Primary screening and exclusion of duplicate manuscripts allowed us to single out the main group of articles (n=121). Some reports were excluded due to non-compliance with inclusion criteria (no description of methods, few references and insufficient data). The final list included 32 studies which were represented by cohort studies, retrospective analyses of surgical interventions, as well as experimental and laboratory studies. Small number of publications did not allow us to obtain unambiguous conclusions. Further research is required to reduce brain retraction trauma.

[Analysis of local hemodynamics in complex aneurysms: an effect of the vessel arising from the dome or the neck]. / Issledovanie lokal'noi gemodinamiki v slozhnykh anevrizmakh: vliyanie sosuda, otkhodyashchego ot kupola ili sheiki.

BACKGROUND: Assessment of rupture risk for intracranial aneurysms (IA) is a particular challenge in cases of so-called complex aneurysms due to their variable morphometric characteristics. Arterial branch arising from the dome or the neck of IA is one of the least explored features of complex aneurysms. The methods of computational fluid dynamics may be valuable to determine the influence of arterial branches of IA on local hemodynamics. OBJECTIVE: To analyze local hemodynamics in IA with arterial branch arising from the cupola or the neck depending on the structure of the aneurysm and blood flow rate in the parent vessel. MATERIAL AND METHODS: CT angiography data of 4 patients with IA were estimated in this study. Modifications of the baseline 3D models of the aneurysms resulted 12 patient-specific models included into analysis. Hemodynamic calculations were made by using of ANSYS Workbench 19 software package. RESULTS: Wall shear stress (WSS) was characterized by the most significant variability, especially in case of sidewall aneurysms. Small cross-sectional area of additional branch in relation to the neck of IA was not followed by considerable changes of blood flow patterns inside IA after «virtual¼ removal of the vessel. Otherwise, the intensity of flows was drastically reduced. Simulation of high inlet flows demonstrated substantial variation of WSS in the area of jet. CONCLUSION: Additional arterial branch arising from the dome or the neck of IA significantly influences local hemodynamics. This influence depends on the localization of IA in relation to the parent vessel and the diameter of additional arterial branch.

[Resection of a giant fusiform aneurysm of the pericallosal artery with «hemi-bonnet bypass¼ procedure (case report and literature review)]. / Vyklyuchenie gigantskoi fuziformnoi anevrizmy perikalleznoi arterii s primeneniem obkhodnogo shuntirovaniya po tipu «hemi-bonnet bypass¼. Sluchai iz praktiki i obzor literatury.

A 30-year-old woman with giant fusiform aneurysm of the azygos anterior cerebral artery is reported. Clipping of the aneurysm followed by modeling of pericallosal artery was performed in 2017. However, further enlargement of the aneurysm has been observed for subsequent 2 years. The patient underwent redo surgery with excision of the aneurysm followed by «hemi-bonnet bypass¼ procedure (anastomosis between superficial temporal artery and anterior cerebral artery with radial artery as an interposition graft). Literature data on reconstructive surgery in the treatment of complex pericallosal artery aneurysms are reviewed.

[Surgical revascularization of the brain in patients with acute ischaemic stroke]. / Khirurgicheskaia revaskuliarizatsiia golovnogo mozga u patsientov s ostrym ishemicheskim insul'tom.

AIM: The study was aimed at developing a surgical policy for patients presenting with acute ischaemic stroke induced by lesions of the intra- and extracranial arteries. PATIENTS AND METHODS: The patients were enrolled into the study resulting from the current practice of the Department of Emergency Neurosurgery of the Research Institute of Emergency Medicine named after N.V. Sklifosovsky. Sampling of patients was carried out from 1st January, 2014 to 10th October, 2017, eventually comprising all those (n=160) operated on for verified pathology of brachiocephalic arteries and acute impairment of cerebral circulation. RESULTS: During the examination, 101 (63.1%) patients were found to have unilateral or bilateral stenosis of the internal carotid artery, 22 (10.7%) patients were diagnosed with occlusion of the internal carotid artery, and 36 (17.6%) had acute thrombosis of the internal carotid artery. All this was the cause of acute impairment of cerebral circulation. Also, 1 patient was found to have occlusion of the 1st segment of the vertebral artery. Depending on the type of the lesion to the internal carotid artery, the patients were subdivided into 3 groups: 1) patients with internal carotid artery stenosis who received carotid endarterectomy; 2) patients with occlusion of the internal carotid artery, subjected to creation of an extra-intracranial microanastomosis, and 3) those with thrombosis of the internal carotid artery, who depending on the degree of occlusion of the internal carotid artery and patency of the intracranial arteries underwent thrombintimectomy or an extra-intracranial microanastomosis. The indications for and contraindications to interventions were defined based on the existing symptomatic pathology of brachiocephalic arteries, the terms of acute impairment of cerebral circulation, perfusion of the brain, the risk for the development of malignant stroke and cerebral oedema, possible haemorrhagic transformation of the focus of ischaemia, the rehabilitational potential of the patient and the analysis of the current literature. The results of our work demonstrated that surgical treatment of patients in the cute period of ischaemic stroke makes it possible to improve the neurological outcomes in patients as compared with the preoperative status and is not accompanied by a high risk of surgical complications (with the haemorrhagic complication rate amounting to 0.6%). CONCLUSION: Surgical revascularization of the brain in the acute period of ischaemic stroke is a safe and effective method of treatment in patients with different haemodynamically significant damage of brachiocephalic arteries, once the patients were correctly selected for the operation.

[Assessing efficacy of carotid endarterectomy by means of intraoperative flowmetry]. / Otsenka éffektivnosti karotidnoi éndarteréktomii s pomoshch'iu intraoperatsionnoi floumetrii.

AIM: The study was aimed at determining volumetric blood flow velocity (VBFV) through the internal carotid artery (ICA) and assessing functional outcomes of treatment of patients, taking into consideration the dynamics of VBFV before and after the operation. PATIENTS AND METHODS: The study comprised a total of 53 patients subjected to examination of VBFV through the ICA before and after carotid endarterectomy (CEA) assessed by means of flowmetry. Neurological deficit was evaluated by means of the NIHS Scale (the M NIHSS prior to operation equalling 2.49), the degree of disability and functional independence of the patient after endured stroke was assessed by the modified Rankin Scale (the M mRS before operation amounting to 1.23) and the Rivermead Mobility Index, the severity of cognitive dysfunctions was determined by the Mini-Mental State Examination (the M MMSE before surgery equalling 24.85) and the Montreal Cognitive Assessment scale (the M MoCA before surgery scoring 23.3). RESULTS: At the first stage of examination we determined that the VBFV after the operation increased in all patients, but the highest values of the increment were observed in groups of patients with ICA stenoses of 80-89% and 90-99%. During the second stage, it was determined that with a higher value of the VBFV after carotid endarterectomy regression of neurological deficit occurred faster (the postoperative M NIHSS scoring 2.09, with the M mRS of 1.00), the patients demonstrated higher results while undergoing the tests for intellectual ability (the postoperative MMSE and MoCA equalling 25.4 and 23.91, respectively) compared with the patients showing low values of the increment of the VBFV after the operation. CONCLUSION: Intraoperative flowmetry is a simple and efficient method of evaluating the VBFV through the ICA, an increase in volumetric blood flow (VBF) contributes to restoration of normal perfusion of the brain and creates prerequisites for more complete and faster restoration of the lost functions after ischaemic stroke (IS) and chronic cerebral ischaemia.

[Surgical prevention of ischaemic strokes by means of an extraintracranial microanastomosis (EICMA) in the carotid basin]. / Khirurgicheskaya profilaktika ishemicheskikh insul'tov s ispol'zovaniem ekstra-intrakranial'nogo mikroanastomoza (EIKMA) v karotidnom basseine.

BACKGROUND: Not less than 50% of all ischaemic strokes appear to occur resulting from pathology of extracranial arteries. Occlusions and stenoses are more commonly encountered in carotid arteries, with the incidence of occlusion of the internal carotid artery (ICA) ranging from 5 to 10% within the structure of all lesions of brachiocephalic arteries (BCA). AIM: The study was aimed at assessing the results of a surgical procedure of extra-intracranial microanastomosis (EICMA) performed in patients presenting with occlusive and stenotic lesions of BCA at the Neurosurgical Department. PATIENTS AND METHODS: During the period between January 1st 2009 to September 30th 2015, specialists of the Neurosurgery Department of the Research Institute of Emergency Medical Care named after N.V. Sklifosovsky treated a total of 1,101 patients presenting with atherosclerotic lesions of BCA, with a total of 1,038 surgical interventions performed. Of these, there were 837 operations of carotid endarterectomy and 180 operations of EICMA in the carotid basin. The indications for performing EICMA in patients from the group with occlusive-stenosing lesions of the major arteries of the head and neck were as follows: the presence of occlusion of the internal carotid artery or M1 segment of the middle cerebral artery, verified by the findings of angiographic examinations; previously endured ischaemic-type cerebral circulation impairment in the basin on the side of occlusion; a decrease in the perfusion reserve of the brain on the side of occlusion by the findings of positron emission tomography (PET), single-photon emission computed tomography (SPECT) or CT-perfusion with loading tests. RESULTS: After performing EICMA, the neurological status in patients averagely improved by 1.2 points according to the NIH Stroke Scale; by 0.5 point according to the Rankin scale, and by 3.5 points according to the Rivermead Mobility Index (Table 1). The dynamics of functional outcomes of EICMA turned out to depend on the terms of the operation (R=2143, p<0.05) and the degree of neurological deficit prior to surgery (R=3422, p<0.05): the deeper the neurological deficiency was and the sooner after acute cerebral ischaemia (ACI) the operation was performed, the more significant restoration of the functions was at the moment of discharge from hospital. Major complications of EICMA in patients operated on at various terms of ischaemic stroke were as follows: recurrent cerebral circulatory impairments - in 6 (3.3%) patients, subdural and intracranial haemorrhage - in 2 (1.1%), temporal deepening of the neurological deficit on the background of reperfusion, confirmed by the findings of SPECT - in 2 (1.1%), pneumonia with a lethal outcome - in 1 (0.6%), fatal ischaemic stroke of the opposite hemisphere - in 1 (0.6%) subject. The lethality rate amounted to 1.1% (2 cases). The risk for the development of complications was higher in elderly and aged patients (75 years and over), in patients with pronounced neurological deficit and significant somatic disorders. CONCLUSION: The indications for surgical prevention of recurrent ischaemic stroke by means of EICMA should be based on the following factors: the presence of confirmed occlusion of the ICA, a history of endured acute cerebral ischaemia, and decreased cerebrovascular reserve. Performing a surgical intervention is not appropriate for patients presenting with pronounced neurological deficit and significant somatic pathology. Careful selection of patients, the use of modern methods of neuroimaging, and intraoperative control make it possible to achieve favourable functional outcomes and to decrease the postoperative complications rate.

[The use of combined revascularization surgery for successful elimination of a middle cerebral artery aneurysm].

OBJECTIVE: The study objective is to present a clinical case of successful surgical treatment of a complex middle cerebral artery (MCA) aneurysm using various types of bypasses. MATERIAL AND METHODS: A 59-year-old female patient presented with nontraumatic intracranial hemorrhage caused by rupture of a complex right MCA aneurysm. The anatomical features of the MCA aneurysm were identified using computed tomography (CT) in angiographic and 3D modes. The surgical intervention included aneurysmectomy and an end-to-end reanastomosis between the M1 and M2 segments of the MCA followed by an extra-intracranial microvascular anastomosis (EICMA) between the frontal branch of the right superficial temporal artery (STA) and the cortical branch of the right MCA located on the frontal lobe surface. RESULTS: The intraoperative blood flow via an intra-intracranial bypass (IC-IC bypass) was 30 mL/min, and the linear velocity of blood flow (LVBF) was 50 cm/s; the blood flow and LVBF via the STA-MCA bypass were 7-8 mL/min and 15 cm/s, respectively. CT angiography performed on the 1st postoperative day revealed the patency of the IC-IC and STA-MCA bypasses. The patient was discharged in satisfactory condition (Glasgow Outcome Scale -V) 1 month after surgery. CONCLUSION: Revascularization surgery is the sought-after surgical technique for complex intracranial aneurysms that enables efficient exclusion of the aneurysm from blood flow and prevention of ischemic brain injuries in the carrying artery territory.

[The use of extra-intracranial microanastomosis in the treatment of cerebral ischemia in patients with nontraumatic subarachnoid hemorrhage]. / Primenenie ekstra-intrakranial'nogo mikroanastomoza v lechenii ishemii golovnogo mozga u bol'nykh s netravmaticheskim subarakhnoidal'nym krovoizliyaniem.

OBJECTIVE: to evaluate the use of extra-intracranial microanastomosis (EICMA) in the treatment of brain ischemia in patients with nontraumatic subarachnoid hemorrhage (SAH). MATERIAL AND METHODS: In the period from 01.01.14 to 01.07.15, there were 229 surgeries for ruptured intracranial aneurysms performed in the urgent surgery unit. Nine patients with marked and widespread angiospasm, subcompensated and decompensated cerebral ischemia underwent the simultaneous clipping of ruptured intracranial aneurysms and EICMA. The age of patients varied from 32 to 52 years (mean 36 years). The severity of patient's state was assessed as III-IV grades on the Hunt and Hess scale before operation. The surgery was performed 1-2 days after admission to the hospital, 1-8 days after the development of SAH. RESULTS AND CONCLUSION: Excellent and good outcome was recorded in 4 patients, severe disability in 3 patients, fatal outcome in 2 patients. The fatal outcome was due to decompensated cerebral ischemia and progressive angiospasm with the high linear blood flow rate and the following reduction in perfusion in the affected hemisphere. The simultaneous clipping of ruptured intracranial aneurysms and EICMA in the acute stage of SAH of patients with subcompensated cerebral ischemia allow to improve treatment RESULTS: This technique is most applicable for patients with proximal angiospasm of M1- and M2-segments of the middle cerebral artery in the first 24 h of the development of a focal neurological deficit supported by the reduction in perfusion in the corresponding vascular area.

[Operations of revascularization in surgery of cerebrovascular aneurysms].

Surgical revascularization of the brain is one of the most important trends in the development of neurosurgery. Restoration of adequate blood flow through pre- and intracerebral arteries promotes prevention and treatment of ischaemic lesions of the brain in various pathology. The present work was aimed at analysing the experience gained in performing revascularizing operations in patients with cerebral aneurysms at the department of neurosurgery. The authors analysed therapeutic outcomes in a total of 45 patients presenting with giant and complex aneurysms of cerebral arteries and treated from 2009 to 2014. Of the 45 patients with giant and complex aneurysms of cerebral arteries, 31 (68.8%) patients underwent open microsurgical interventions (including 10 patients with the use of different variants of revascularizing operation) and 14 (31.2%) patients were subjected to endovascular exclusion of the aneurysm from the blood flow. It was shown that performing revascularizing operations in patients with complex and giant aneurysms of cerebral arteries makes it possible to compensate circulation in the interested arterial basin and to obtain good functional results.

ASSESSMENT OF CEREBRAL PERFUSION IN PATIENTS WITH HEMODYNAMIC ISCHEMIC STROKE UNDERGOING RECONSTRUCTIVE BRACHIOCEPHALIC ARTERY INTERVENTIONS.

The paper deals with the assessment of cerebral perfusion in patients in the acute period of acute cerebrovascular accident before and after revascularization surgery. It gives a clinical example of using contrast-free perfusion magnetic resonance imaging (MRI) in a patient with hemodynamic ischemic stroke. The use of this technique made it possible to determine indications for early carotid endarterectomy for the contralateral internal carotid artery and to evaluate positive postoperative changes in cerebral perfusion and the patient's neurological status. The authors analyzed the current literature on this problem with a particular emphasis on the possibilities of using dynamic susceptibility contrast-enhanced and arterial spin-labeling contrast-free perfusion MRI in this category of patients. Carotid endarterectomy in the acute period of acute cerebrovascular accident can improve cerebral hemodynamics and the patient's neurological status and prevent recurrent cerebral circulatory disorders. Indications for this surgery should be determined by taking into consideration the results of perfusion MRI techniques (single-photon computed tomography contrastenhanced and contrast-free perfusion MRI).

[High-flow extracranial-intracranial (EC-IC) bypass surgery in a patient with giant right cavernous ica aneurysm].

To present the clinical case of successful extracranial-intracranial (EC-IC) high-flow bypass performance. Patient, female, 51 years old, was suffered from giant cavernous aneurysm of right internal carotid artery (ICA), presented with mass effect. The EC-IC high-flow bypass using radial artery was performed between M2 segment of right middle cerebral artery and right external carotid artery. Bypass patency was confirmed by intraoperative dopplerography, postoperative digital subtraction angiography and by ultrasound examination of anasthomosis. Patient was discharged in 3 weeks after operation in satisfactory condition. The EC-IC high-flow bypass is one of effective method for cavernous aneurysm treatment, allowing excluding aneurysm from cerebral blood flow and decreasing its mass effect.

[Morphological, clinical, diagnostic features and the treatment of patients with giant brain aneurisms].

Retrospective analysis of treatment outcomes of 89 patients with GIAs, treated in Sklifosovsky Emergency Care Institute from 01.01.1992 till 30.11.2010, was performed. 67 patients were operated on, among them open surgery was conducted for 49 patients, endovascular embolisation - 18 patients. Severity of patients' condition was assessed according to Hunt - Hess (H-H) scale, level of consciousness - Glasgow Coma Scale (GCS), treatment outcomes - Glasgow Outcomes Scale (GOS). Hemorrhage due to GIA rupture was seen at у 64 (72,0%) patients, mass lesion signs - at 18 (20,2%), embolic events - at 3 (3,4%) and GIA without any symptoms - at 4 (4,4%) patients. Good and excellent outcomes were at 79,1% operated patients, total lethality among operated patients was 13,4%. Lethality among non-operated patients was 47,4%. Conservative treatment of patients with GIAs has low perspectives. Open and endovascular operative interventions are the high-risk surgery but they allow decreasing the lethality and morbidity rate among these patients compared with conservative treatment.