Background. Cavernoma of cavernous sinus is a fairly rare benign neoplasm, accounting for less than 3 % of all neoplasms in this area. Due to the rarity of this pathology, a standardized protocol for diagnosis or treatment has not been developed. Surgical and radiosurgical methods are used for treatment.

Aim. Analysis of the results of treatment of patients with cavernous sinus cavernomas operated at the N. N. Burdenko National Medical Research Center of Neurosurgery from 2000 to 2022 using endoscopic transnasal access.

Materials and methods. We present our own experience in the treatment of 9 patients who underwent transnasal endoscopic removal of cavernous sinus cavernoma.

Results. A total of about 300 cases of treatment of patients with cavernous sinus cavernomas have been described in the literature, and endoscopic removal has been described in only 12 cases.

As a result, subtotal removal was achieved in 7 cases. In 2 cases, the removal was partial. The postoperative period proceeded in all patients without peculiarities and without complications.

Conclusion. Endoscopic transnasal access allows partial or subtotal removal of the formation without risk of injury to cranial nerves and with minimal soft tissue injury, which has a positive effect on the postoperative period of patients. In combination with radiosurgical methods, it is possible to achieve satisfactory treatment results.

Aim. To estimate the nearest and distant angiographic results of endovascular occlusion of aneurysms of the internal carotid artery ophthalmic segment using non‑reconstructive treatment methods.

Materials and methods. The results of endovascular treatment of 75 patients with aneurysms of the ophthalmic segment of the internal carotid artery admitted to the Neurosurgical Department No. 3 of the V. L. Polenov Russian Research Neurosurgical Institute, from January 1, 2013 to December 31, 2016 were analyzed.

Results. Of 75 aneurysms, 52 (69.3 %) were radically occluded from the blood flow (Type A) and 23 (30.7 %) were sub‑totally (Type B). When isolated occlusion with detachable coils was used, radical result was achieved in 13 (59.1 %) out of 22 cases, subtotal occlusion – in 9 (40.9 %). During balloon‑assisted occlusion 39 (73.6 %) out of 53 aneurysms were shut off from the blood flow totally, 14 (26.4 %) – sub‑totally. Partial aneurysm occlusion (Type C) was not achieved in any of the observations. Recurrence was observed in 3 (30 %) out of 10 cases on control angiography after isolated occlusion with detached spirals, and 2 (20 %) required repeated surgical intervention. From 38 aneurysms operated on using balloon‑assistence, 9 (23,7 %) recurred on control angiography, 6 of them (15,8 %) required repeated surgical intervention.

Conclusion. Nonconstructive surgical interventions for occlusion of aneurysms of the internal carotid artery ophthalmic segment are still urgent and effective method of treatment of patients in acute period of aneurysm rupture combined with somatic status; however, they are inferior to reconstructive surgeries concerning radica lity in the long‑term period.

Aim. To evaluate short‑ and long‑term effectiveness of low‑flow bypass between superficial temporal artery and M4 segment of middle cerebral artery (low‑flow STA‑MCA bypass) in patients with symptomatic occlusion of the internal carotid artery (ICA).

Materials and methods. Between 2016 and 2019 at the Department of Neurosurgery of the N. V. Sklifosovsky Research Institute of Emergency Medicine, 54 patients who underwent low‑flow STA‑MCA bypass formation at the side of symptomatic ICA occlusion between 2013 and 2015 were examined. Symptomatic ICA occlusion was more common in men than in women (7:1 ratio). Patient age varied between 48 and 73 years (mean age was 62 years).

During low‑flow STA‑MCA bypass formation surgery for symptomatic ICA occlusion, intraoperative flowmetry was used in 52 (96 %) patients, in 2 (4 %) patients this diagnostic method was impossible to perform due to technical difficulties. The main examination methods in the long term after cerebral revascularization were evaluation of neurological status dynamics per the National Institute of Health Stroke Scale (NIHSS); modified Rankin scale; Rivermead mobility index; computed tomography angiography of the extra‑intracranial arteries; ultrasound (US) examination of the STA‑MCA bypass for eval uation of linear and volumetric blood flow velocities; single‑photon emission computed tomography. The type and size of trephination were evaluated, and operative time was taken into account.

The patients were divided into 3 groups: group 1 included patients with follow‑up period of 1–2 years after cerebral revascularization, group 2 – 3–4 years, group 3 – 5–6 years. All results were compared to preoperative, early, and longterm measurements.

Results. In the long‑term postoperative period between 1 and 6 years after cerebral revascularization, 54 patients were examined. Computed tomography angiography and US showed functioning STA‑MCA bypass in 53 (98 %) patients. According to single‑photon emission computed tomography of the brain, regional cerebral blood flow in the longterm postoperative period varied between 28 and 40 mL / 100 g / min, median regional cerebral blood flow in the long‑term postoperative period was 38 mL / 100 g / min. Intraoperative flowmetry was performed in 52 (96 %) patients, median was 15.5 mL / min. US showed that linear blood flow velocity in the STA‑MCA bypass varied between 20 and 95 cm / s, median was 49 cm / s. Volumetric blood flow varied between 30 and 85 mL / min with median of 75 mL / min.

Resection trephination was performed in 36 (67 %) patients, mean size of trephination hole was 3 cm³. In the study, operative time was measured: mean value was 212 min; no significant correlation between operative time and trephination size was observed.

Improved neurological status was observed in all study groups. Per the NIHSS, in group 1 (1–2 years) improvement was observed in 59 % of patients, in group 2 (3–4 years) in 48 %, in group 3 (5–6 years) in 47 %. Per the modified Rankin scale, in group 1 improvement was observed in 36.4 % of patients, in group 2 – in 48 %, in group 3 – in 42.9 %. Per the Rivermead mobility index, in group 1 improvement was observed in 63.3 % patients, in group 2 – in 56 %; in group 3 – in 57.1 %. The best outcomes were observed in group 1 (63.3 %).

Conclusion. Instrumental diagnostic methods and evaluation of neurological status showed positive dynamics both in the postoperative period and in long‑term period between 1 and 6 years after low‑flow STA‑MCA bypass formation. In the long term, repeat abnormalities of cerebral blood flow of ischemic type and repeat transient ischemic attacks were not observed. Correct selection of patients in the preoperative period and comprehensive treatment including drug therapy in the postoperative and long‑term periods allow to prevent repeat ischemic cerebrovascular disease and therefore improve patients’ quality of life.

Background. Stereotactic operations on the ventral‑intermediate nucleus of the thalamus (Vim) and the posterior subthalamic area (PSA) are used for the surgical treatment of tremor. Since these structures are invisible in standard magnetic resonance imaging (MRI) regimes, indirect stereotactic guidance is mainly used during operations. MRI tractography allows taking into account the individual variability of the target structures for tremor, visualizing the target directly, but this technique has not yet entered the routine practice of preparing operations.

Aim. The aim of the work is to study the variability of the position of the dentato‑rubro‑thalamic tract (DRT), determined according to MRI tractography data, in relation to the main reference points for indirect stereotactic guidance, as well as to the visible landmarks on MRI in FGATIR mode, to assess the validity of the currently used methods of preparing operations in patients with tremor.

Materials and methods. Probabilistic MRI tractography of DRT based on the HARDY protocol was performed in 34 patients. Additionally, 3D T1 tomograms were obtained with axial slices with an isotropic voxel size equal to 1 mm, as well as FLAIR sagittal slices with a thickness of 1.12 and a pitch of 0.56 mm. Eleven patients additionally underwent a series of MRI sections according to the FGATIR program with a thickness of 1 mm, without an intersectional gap.

Results. A significant variability of the DRT position has been established both in the coordinate system of the anterior and posterior commissures, and in relation to standard targets for indirect stereotactic guidance. In addition, a visible interhemispheric asymmetry of the position of the tracts was revealed. The smallest degree of deviation from the tract was noted for the trajectories of deep brain stimulation electrodes implanted in the caudal zona incerta (cZI) at the level of the maximum diameter of the red nuclei. A high degree of correspondence between the tract and the target zone of prelemniscal radiations (Raprl) was also established on tomograms in the FGATIR mode.

Conclusions. The standard target points for the indirect targeting of Vim targets and the cerebello‑thalamic tract in PSA give a deviation of more than 2 mm from DRT in almost half of patients. During the use of cZI as a standard target for indirect guidance in the treatment of tremor, the DRT is located at the zone of stereotactic impact at the level of the 2^nd or 3^rd contact of the electrode in 76.5 % of cases. FGATIR mode allows visualizing the structure of Raprl, with stereotactic guidance on which the effect on the DRT can be achieved in 86.4 % of cases.

Background. Traumatic brain injury (TBI) remains a big problem of modern neurosurgery, accompanied by high rates of disability and lethality. Venous thromboembolism (VTE) including venous thrombosis and pulmonary embolism (PE) plays a significant role in the structure of mortality in this pathology. Regimens and schemes of pharmacological prevention of VTE in TBI as well as corresponding preventative measures are not yet determined completely.

Aim. To identify the frequency of VTE in patients with isolated moderate and severe TBI, and to evaluate the results of prevention and treatment of these complications in patients of this category.

Materials and methods. Over a 3‑year period (from 2020 to 2023) 73 patients with isolated moderate and severe TBI (51 men and 22 women, mean age 61.0 ± 13.0 years) were treated in the V. M. Buyanov City Clinical Hospital. Of these, 31 patients received only conservative therapy, and 42 patients underwent surgery (craniotomy with hematoma removal, closed external hematoma drainage, and installation of intracranial pressure sensor). Ultrasound examination of the lower limb veins was performed at patient admission, then every 7 days until discharge from the hospital. Pharmacological prevention of VTE using low molecular weight heparin in non‑surgical patients was started after 1–2 days if computed tomography of the brain 24 h after admission showed no negative hematoma dynamics. Surgical patients were prescribed preventive medications 24 h after surgery if computed tomography confirmed intracranial hemostasis.

Results. Venous thrombosis was detected in 22 (30.1 %) of 73 patients. PE complicated the underlying disease in 1 (1.4 %) case and was non‑fatal. There was no fatal PE in the study group. An increase of the initial intracranial hematoma volume occurred in 3 (4.1 %) patients, in 2 (2.8 %) patients the recurrence of hemorrhage occurred before the beginning of heparin administration, and in 1 (1.4 %) case against the background of therapeutic doses of anticoagulants prescribed for venous thrombosis. In the majority of cases (82.0 %; 18 of 22 patients) thromboses were localized in deep veins of the lower leg and were asymptomatic. Intrahospital mortality was 23.3 % (17 patients), all lethal outcomes were due to the course of traumatic brain disease.

Conclusion. VTE is a frequent complication of TBI with intracranial hemorrhage. Regular ultrasound diagnostics makes it possible to diagnose asymptomatic distal venous thrombosis in a timely manner and to prescribe therapeutic doses of low molecular weight heparin in time which in turn allows to avoid fatal PE. Currently, there are no clear domestic recommendations for the prevention and, most importantly, for the treatment of these complications in patients with isolated moderate and severe TBI, which requires further active study of this problem.

Background. Physiological hand tremor is one of significant problems in microsurgical technique. One careless movement can cause damage to the neighboring structures and consequently worsen a patient’s condition. Therefore, the problem of reducing hand tremor remains relevant.

Aim. To determine the effect of microsurgeon’s pose, duration of operation on the accuracy of surgical action and level of microsurgical hand tremor.

Materials and methods. The study included 14 neurosurgery residents satisfying inclusion criteria. For evaluation and simulation of microsurgical action, validated and developed by the study authors devices for testing and surgical  microscope Carl Zeiss were used. The experimental results were compared using univariate analysis. The differences were considered statistically significant at p <0.05.

Results. Surgeon’s pose standing / sitting did not affect spatial accuracy of surgical action and the level of microsurgical hand tremor. However, statistically significant changes in hand tremor were observed both in standing and sitting positions with increased time of microsurgical action.

Conclusion. The choice between sitting or standing pose for microsurgical operation is not a factor significantly affecting microsurgeon’s spatial accuracy of movement and hand tremor. Duration of surgical intervention affects the level of microsurgical hand tremor.

Intermediate nerve neuralgia (INN) is a rare pathology with difficult diagnostics and currently there is no generally accepted surgical management protocol. In this regard, an optimal surgical strategy in this case is a difficult task. The aim was to determine an optimal approach for surgical management of patients with INN using intraoperative neurophysiological monitoring (IONM).

The INN was diagnosed in a patient, a vestibulo‑cochlear complex dissection with intermediate nerve sectioning under IONM control of was performed intraoperatively. There was the earache regression, but there were gustatory disorders in the anterior portion on the left side of the tongue in the early postoperative period. In the late postoperative period, a delayed facial nerve paresis and signs of liquorrhea were diagnosed, which were completely regressed after reoperation and medication. The follow‑up period was more than 12 months; a stable regression of otoalgia was achieved. Intermediate nerve sectioning is an effective and common technique for the treatment of patients with INN. IONM improves surgical results and reduces a likelihood of different complications.

COVID‑19‑associated osteomyelitis is a purulo‑necrotic complication of past coronaviral infection. The majority of described cases of this complication are caused by Mucorales fungi. Mucormycosis is a severe complication of COVID‑19 associated with high mortality rate. Most commonly it affects maxillary sinuses, facial bones, and orbits. Due to quick progression of the disease, it is important to remember the association between COVID‑19 infection and purulo‑necrotic lesions of the skull that can be complicated by brain involvement.

The article presents a very rare observation of COVID‑19‑associated osteomyelitis affecting the squamous part of the frontal bone complicated by formation of bilateral symmetrical subgaleal abscesses in the projection of the frontal eminences.

Encephalocele or craniocerebral hernia is a disease in which there is a prolapse of the meninges and structures of the brain through a skull defect. Clinically, they are manifested by a violation of nasal breathing, deformation of the naso‑ethmoid region, and nasal liquorrhea. Various inflammatory complications (meningitis, meningoencephalitis, ventriculitis, brain abscess) can occur against the background of persistent hernia, while mortality is 8–10 %.

Basal encephalocele is a rare pathology that requires an integrated approach in a specialized hospital using high‑tech equipment. Therapeutic tactics and risks are determined individually based on the patient’s age, current symptoms, size of the nasal cavity, location and size of the skull base defect. In the absence of nasal liquorrhea, it is possible to delay surgical treatment in order to be able to use an autologous bone of the calvarium, to collect a larger periosteal flap, to perform the operation using a combined approach and to minimize surgical complications. With endonasal endoscopic access, it is necessary to separate the encephalocele from the surrounding tissues, completely remove the hernial sac and visualize the bone edges of the defect, and then perform its plastic closure.

Despite the fact that in most cases the existing methods of treatment are very effective, in a number of cases it is not possible to achieve the desired result. This article presents two rare clinical cases in which patients with basal encephalocele required reoperation for herniation and skull base defect repair.

Vestibular schwannomas are the most common tumors in the cerebellopontine angle. Stereotactic radiosurgery is included in the armamentarium of methods for treating these tumors along with surgical treatment. Given the annual incidence of more than 15 radiosurgical cases of vestibular schwannomas per 1 million population, the expected need for stereotactic radiosurgery of these tumors in Russia is more than 2000 cases annually.

Stereotactic radiosurgery is located at the intersection of several clinical specialties: neuroradiology, neurosurgery and radiation therapy, each of which has made a significant contribution to the development of this treatment method. The most commonly used for this is the cobalt‑based Leksell Gamma Knife, specifically intended for the treatment of intracranial neoplasms. Treatment is also possible with modern linear accelerators and proton accelerators, which provide high accuracy and conformity of irradiation. The experience gained since the first application of this method in the treatment of vestibular schwannomas has made it possible not only to optimize the radiation doses to the tumor and adjacent critical structures (brain stem, inner ear), but also to study the features of post‑radiation micro‑ and macro‑ changes, their impact on the clinical course, to develop recommendations for radiosurgery with schwannomas of various sizes. All this contributes to high control of tumor growth and a low level of functional disorders, which, along with easy tolerability and minimal hospitalization time, determines lower cost of this treatment compared to the traditional surgical approach and significant social and economic effect.

This lecture is intended for neurosurgeons and radiation therapists and focuses on the most significant factors that influenced the development, promotion and active use of stereotactic radiosurgery of vestibular schwannomas in cli nical practice.

Variants of atypical structure and location of anatomical structures always complicate the course of surgical access and admission and are often the causes of surgical errors and complications. This article presents an overview of some features of variant anatomy in areas of interest to neurosurgeons, including those leading to the development of intraoperative problems and postoperative neurological deficits.

The main message of the article is not only that neurosurgeons should plan surgery taking into account individual anatomical variability starting with the shape of the skull, but also that in cases of adverse perioperative events, atypical anatomy should be taken into account as an objective risk factor and have a mitigating value in the evaluation of the neurosurgeon’s performance.

The aim of this paper is to present and analyse scientific publications on variant anatomy, determining its role in the development of surgical errors and complications in neurosurgery.

Awake surgery is usually used to save patient’s speech. Various tests are applied for this purpose, whish selection  depends on tumor location. In multilingual patients verbal centers usually have different position. Location of each of them is necessary to keep patient’s communication capabilities after operation.

To study vision, tests with presentations of color points or pictures on the screen divided on 4 parts are used. Such testing allows to estimate vision and speech simultaneously.

Mapping of motor area in awake patients allows to evaluate this function more comprehensively including motion planning, proprioceptive control and balance. Stimulation of sensory area in awake patients gives opportunity to differ various types of sensitivity.

Mapping and keeping of cognitive functions, memory, attention and ability of calculation increases chance to save professional skills and quality of life after operation.

Due to its rarity and complex etiopathogenesis, spontaneous cerebrospinal fluid rhinorrhea remains an understudied problem. Similarity of symptoms with other disorders of the ENT organs, low vigilance of primary care specialists lead to delayed diagnosis and treatment increasing the risk of complications. In recent years, diagnosis and treatment of this pathology have received a higher level of attention as evidenced by increased number of publications on this topic.

The review considers in detail the problems of etiopathogenesis, classification, diagnosis and treatment of spontaneous cerebrospinal fluid rhinorrhea based on current data from scientific literature.