[Regarding the manuscript by A.A. Shulgina et al. Combined double-barrel direct and indirect bilateral cerebral revascularization in the treatment of moyamoya disease]. / Po povodu stat'i A.A. Shul'ginoi i soavt. «Sochetanie kombinirovannoi dvustvol'noi pryamoi i nepryamoi revaskulyarizatsii golovnogo mozga s dvukh storon v lechenii bolezni moyamoya¼. Diskussiya i obzor literatury.

In the paper published in issue 2 (2020) of the Burdenko's Journal of Neurosurgery, the authors justifiably propose a technique of bilateral extraintracranial vascular microanastomosis (EICMA) in case of rapidly developing stenotic lesions of the intracranial arteries in order to compensate the marked hypoperfusion in the basins of the anterior cerebral artery and middle cerebral artery on both sides. This allows to significantly reduce the risks of possible ischemic stroke in the earliest period.

On the optimal choice of a hyperelastic model of ruptured and unruptured cerebral aneurysm.

In the last decade, preoperative modelling of the treatment of cerebral aneurysms is being actively developed. Fluid-structure interaction problem is a key point of a such modelling. Hence arises the question about the reasonable choice of the model of the vessel and aneurysm wall material to build the adequate model from the physical point of view. This study covers experimental investigation of 8 tissue samples of cerebral aneurysms and 1 tissue sample of a healthy cerebral artery. Results on statistical significance in ultimate stress for the classification of 2 cohorts of aneurysms: ruptured and unruptured described earlier in the literature were confirmed (p ≤ 0.01). We used the four most common models of hyperelastic material: Yeoh, Neo-Hookean and Mooney-Rivlin (3 and 5 parameter) models to describe the experimental data. In this study for the first time, we obtained a classification of hyperelastic models of cerebral aneurysm tissue, which allows to choose the most appropriate model for the simulation problems requirements depending on the physical interpretation of the considered problem: aneurysm status and range of deformation.

[Use of a mini-approach for performing EC-IC bypass in occlusive lesions of the brachiocephalic arteries]. / Primenenie mini-dostupa dlia sozdaniia ékstra-intrakranial'nogo mikroanastomoza pri okkliuziruiushchikh porazheniiakh brakhitsefal'nykh arterii.

PURPOSE: to evaluate the advantages and disadvantages of a mini-approach for performing EC-IC bypass. MATERIAL AND METHODS: The mini-approach was used in 35 patients (32 males and 3 females) with symptomatic occlusive lesions of the brachiocephalic arteries (BCAs) who were treated at the Department of Vascular Neurosurgery of the Federal Center of Neurosurgery in Novosibirsk in the period between January and December 2014. The mini-approach was performed through a skin incision of up to 5.5 cm in the donor artery projection. The approach was planned based on comparison of the MSCT-angiography data. RESULTS: In all cases, the mini-approach enabled performing EC-IC bypass in the optimal location, with the minimal involvement of the donor artery and the minimal size of craniotomy. Complications (shunt thrombosis) in the early postoperative period occurred in 3 (8.5%) cases. There were no cases of marginal wound necrosis. The mean bed-day was 7 days. DISCUSSION: We analyzed the literature regarding using the mini-approach in combination with various mapping variants based on neuroimaging data. CONCLUSION: The approach has a high potential for wide application in clinical practice. The disadvantage is the narrowness and depth of the surgical wound, which complicates manipulations when performing EC-IC bypass and requires special skills.

[Combination treatment of cerebral arteriovenous malformations using endovascular and microsurgical techniques]. / Kombinirovannoe lechenie arteriovenoznykh mal'formatsii golovnogo mozga s ispol'zovaniem éndovaskuliarnogo i mikrokhirurgicheskogo metodov.

MATERIAL AND METHODS: The study included 40 patients with cerebral AVMs. In the study group, 14 (35%) patients underwent microsurgical resection without preliminary embolization (1st group), and 26 (65%) patients underwent combined treatment (endovascular embolization and microsurgical intervention, 2nd group). The first group included patients with S&M grade I-III AVMs, and the second group included patients with S&M grade II-V AVMs. Treatment outcomes were evaluated with allowance for completeness of AVM resection, operative blood loss, duration of surgery, changes in clinical and neurological impairments according to the modified Rankin scale, and rate of neurological and surgical complications. RESULTS: According to postoperative findings, AVMs were totally resected in all patients. Persistent focal neurological symptoms developed in 2 (7.7%) cases in the second group; neurological complications occurred in 1 (7.1%) patient in the first group. The mean blood loss during resection of AVMs without preliminary embolization and embolized AVMs in patients with S&M grade I-III AVMs was 271.4 mL and 149.1 mL, respectively. The duration of surgery and blood loss did not differ significantly in microsurgery and combination treatment groups. CONCLUSION: Combination treatment, including microsurgical intervention after endovascular embolization, is an effective treatment for AVMs, in particular for high grade (S&M grade III-V) AVMs. Teamwork and coordination among the surgeon, endovascular surgeon, and radiologist in treatment of AVMs is a prerequisite for a good outcome.

[The use of high-flow extracranial-intracranial artery bypass in pathology of the cerebral and brachiocephalic arteries: technical features and surgical outcomes]. / Ispol'zovanie metoda obkhodnogo vysokopotochnogo ékstra-intrakranial'nogo arterial'nogo shuntirovaniia pri patologii tserebral'nykh i brakhiotsefal'nykh arteriĭ: tekhnicheskie osobennosti i rezul'taty operatsiĭ.

BACKGROUND: Poor outcomes of surgical treatment for complex cerebral aneurysms due to the development of cerebral ischemia were the cause to use cerebral revascularization surgery for this pathology. OBJECTIVE: the study objective was to master a high-flow extracranial-intracranial (EC-IC) artery bypass technique and evaluate its application in surgical treatment of complex and giant cerebral aneurysms as well as complex lesions of the brachiocephalic arteries. MATERIAL AND METHODS: Fifty two patients underwent high-flow IC-EC bypass surgery; of these, 34 patients had complex cerebral aneurysms, and 18 patients had complex stenotic occlusive lesions of the brachiocephalic arteries. After bypass placement, the patients with aneurysms underwent different variants of aneurysm exclusion (trapping or proximal clipping/ligation of the parent artery). All patients underwent follow-up studies of the bypass function and clinical condition in the early postoperative period and 6 and 12 months after surgery. RESULTS: High-flow IC-EC bypass surgery is routinely used in clinical practice of the Novosibirsk Federal Center of Neurosurgery. Fifty one out of the 52 patients were followed-up in a range of 4 to 56 months. According to the direct or CT angiography data, bypasses functioned in 51 (98.1%) patients in the early and long-term postoperative periods. The clinical efficacy (no ischemic changes and improved cerebral perfusion) of high-flow IC-EC bypasses was demonstrated in 31 (91.2%) of 34 patients with aneurysms and in 17 (94.4%) of 18 patients with complex lesions of the brachiocephalic arteries. The total number of surgical complications was 8 (15.4%) cases: 7 complications occurred in patients with aneurysms, and 1 complication developed in a patient with bilateral ICA occlusion. Of these, ischemic complications developed in 4 (7.7%) cases, hemorrhagic complications occurred in 2 (3.8%) cases, and cranial nerve complications were found in 2 (3.8%) cases. One (1.9%) female patient with a giant aneurysm died from hemispheric stroke due to insufficient blood flow through the bypass. CONCLUSION: Implementation of a large number of surgeries enabled improvement of the technique and clarification of the prerequisites for preoperative examination, intraoperative control, and postoperative management of patients. A low mortalits rate suggests this technique for use in clinical practice. The surgery is indicated for the treatment of giant aneurysms of the petrous, cavernous, and clinoid segments of the ICA. In the case of giant supraclinoid aneurysms, the surgery may be combined with removal of thrombotic masses from the aneurysm sac for rapid decompression of the cranial nerves. Application of this surgery for treatment of giant aneurysms of the trunk and bifurcation of the basilar artery is promising but requires further investigation. The surgery is also recommended for improving cerebral perfusion in the setting of complex stenotic occlusive lesions of the BCA: prolonged BCA stenoses, tandem ICA stenoses located in both the extracranial and intracranial segments, nonspecific vasculitis and arteriitis, subcranial aneurysms, kinking etc.

[Surgical treatment of «Mirror¼ aneurysms of the internal carotid artery]. / Khirurgicheskoe lechenie «zerkal'nykh¼ anevrizm vnutrennei sonnoi arterii.

BACKGROUND: A relatively high occurrence of "mirror" aneurysms of the anterior cerebral circulation in neurosurgical practice necessitates generalization of experience of using different surgical approaches. The choice of treatment is usually associated with the number of surgical stages. MATERIAL AND METHODS: Forty nine patients (19 males and 30 females) with mirror aneurysms of the anterior circulation underwent one- and two-step surgery at the Novosibirsk Federal Center of Neurosurgery in 2013-2015. The total number of bilateral aneurysms was 51 couples (102 aneurysms). The patients' age ranged from 19 to 66 years (mean age, 47.1±11.6 years). Most of the patients (47) underwent elective surgery; 2 patients were operated on in acute subarachnoid hemorrhage. RESULTS: Sixty nine microsurgical operations and 19 endovasal interventions were performed during the main step. Microsurgery alone was used in 34 cases; endovascular surgery alone was performed in 6 cases; a combination of the techniques was used in 9 cases. Ten patients underwent one-step surgery, and 39 patients underwent two-step surgery. The radicalness of surgery amounted to 94.1% for the microsurgical technique and 83.3% for the endovasal technique. The excellent and good functional outcome (modified Rankin scale, 0-2) was achieved in 46 (93.9%) patients, and the poor outcome (mRs, 3-5) was observed in 3 (6.1%) patients. CONCLUSION: Generalization of the results indicates that one-stage surgery is more preferable in the treatment of mirror cerebral aneurysms. However, the two-stage approach remains important and, in the case of certain anatomical peculiarities, is the only possible treatment. A combination of microsurgical and endovascular techniques improves clinical outcomes in treatment of mirror aneurysms of the anterior part of the cerebral arterial circle.