Radiofrequency (RF) lesioning is a precise and established destructive technique in functional neurosurgery for treating chronic pain, movement disorders, and other conditions. This paper reviews its history, technical evolution, and key applications such as trigeminal gangliolysis, cordotomy, and deep brain lesioning. Despite being irreversible and less commonly practiced today due to the rise of neuromodulation, RF lesioning offers significant advantages like predictability, minimal invasiveness, and cost-effectiveness, making it a valuable option for specific patients, particularly in oncology pain care.

Introduction. Augmented reality (AR) technologies allow a surgeon to overlay three-dimensional virtual models onto real objects, enhancing visualization and facilitating the performance of complex surgeries. The primary objective of using AR in surgery is the precise alignment of the virtual model with the patient’s real anatomy, enabling the surgeon to see key anatomical structures as a projection onto or inside the body.

Materials and methods. The study utilized Microsoft Hololens 2 HMD (head-mounted display) glasses and the “Medgital” software for AR navigation. This article presents the results of a technical comparison of three methods for aligning AR 3D models with a patient’s head: alignment using craniometric points, the use of a QR code and a 3D printed frame and the application of pre-programmed points with a 3D pointer. The accuracy of fiducial point registration was assessed using the fiducial registration error (FRE) metric, and the execution time was measured for each method, allowing for the determination of their advantages and limitations.

Results. The mean FRE for alignment using craniometric points was 1.1 ± 0.3 cm, for the method using a QR code and a 3D printed frame it was 0.4 ± 0.3 cm, and for the method using pre-programmed points and a 3D pointer it was 0.7 ± 0.6 cm. The average alignment time was 180, 5, and 100 seconds, respectively. It was found that the method using the QR code and the 3D frame offered the highest accuracy, making it preferable for most clinical situations.

Conclusion. Each method has its own strengths and weaknesses; the choice depends on the clinical situation, available equipment, and required accuracy. The integration of AR technologies with surgical techniques improves the safety and precision of operative interventions.

Introduction. Aneurysms of the posterior inferior cerebellar artery (PICA) account for approximately 0.36–4.5 % of all intracranial aneurysms. The rupture rate reaches 77–88 %, and the risk of rerupture is 71–78 %. Currently, microsurgical and endovascular treatment methods are competing. However, despite their advantages, endovascular interventions for ruptured aneurysms have a number of drawbacks. According to modern protocols, the treatment of choice for excluding PICA aneurysms from the circulation in the acute period of subarachnoid hemorrhage (SAH) is microsurgical clipping.

The aim of this study. To evaluate the immediate and long-term outcomes, as well as the quality of life and return to work after microsurgical treatment of PICA aneurysms in the acute stage of SAH.

Materials and methods. A retrospective study included 32 patients operated on in the acute stage of SAH at the Moscow Regional Research and Clinical Institute from June 2019 to December 2024.

Results. Patients admitted to the hospital in a compensated state (13–15 points on the Glasgow Coma Scale (GCS), Grade 1 and 2 on the Hunt – Hess scale) showed favorable clinical outcomes after treatment (mean Glasgow Outcome Scale (GOS) score – 7.4). Favorable clinical outcomes were also noted among decompensated patients (9–12 points on the GCS, Grade 3 and 4 on the Hunt – Hess scale) (mean GOS score – 6.9). Mortality was 6.2 % (n = 2). Distribution of patients according to the EQ-5D-3L health questionnaire: full recovery – 15 (55.7 %), good recovery – 7 (25.9 %), other patients – 5 (18.5 %). According to the patients’ subjective assessment of their health status, the mean value was 79.8 ± 12.9 points. Twenty patients (74.1 %) returned to work.

Conclusion. Microsurgical treatment of PICA aneurysms is a safe and effective method with favorable immediate and long-term outcomes. Good quality of life and return to work were observed in more than 74% of patients.

The removal of large and giant vestibular schwannomas remains one of the most challenging tasks in neurosurgery. The probability of anatomical injury to the facial nerve during the removal of these neoplasms is 10.3–17%. Objective of the article was to analyze the frequency and risk factors for anatomical injury of the facial nerve during the removal of large and giant vestibular schwannomas.

Materials and methods. A total of 93 patients were examined. To determine risk factors, linear and angular parameters of the posterior cranial fossa, magnetic resonance characteristics of the tumor, as well as clinical and intraoperative data were investigated. Statistical analysis was performed using the Statistica software package (version 10.0) for Windows (StatSoft, USA). Statistical significance was assessed using the Mann – Whitney U test, Pearson’s χ2 test, or Fisher’s exact test for categorical data.

Results. Anatomical injury to the facial nerve during tumor removal was recorded in 8 patients, accounting for 8.6%. The length of the posterior cranial fossa was statistically significantly smaller than in the comparison group: 73.3 mm and 78.8 mm, respectively (U = 491.0, p = 0.039). The width of the posterior cranial fossa was also smaller but without statistical significance: 108.8 mm and 113.3 mm, respectively (U = 433.0, p = 0.205). According to MRI results, patients in the main group more frequently exhibited peritumoral edema (p = 0.345), hydrocephalus and periventricular edema (p = 0.204), and absence of a cerebrospinal fluid (CSF) cleft (p = 0.426). According to CT perfusion data, a higher CBF (cerebral blood flow) index was noted in the tumor tissue (p = 0.800). The identified differences were not statistically significant. Among intraoperative risk factors, the radicality of tumor removal should be noted. In the main group, all tumors were removed radically, while in the comparison group, the percentage of radically resected schwannomas was only 62.3% (p = 0.047).

Conclusion. In addition to well-known factors leading to an increased risk of intraoperative nerve injury, we also identified the influence of anatomical features of the posterior cranial fossa structure. This complication occurs more often in patients with a narrow and short fossa. The probability of anatomical injury to the facial nerve during radical removal of large and giant vestibular schwannomas is statistically significantly higher compared to subtotal removal.

Introduction. The degree of invasion of meningiomas of the anterior oblique process into the main vessels of the brain directly correlates with the radicality of their removal. The creation of safety bypass arterial shunts is one of the ways to increase the radicality of operations.

Case description. A 36-year-old patient was admitted to the Regional Clinical Hospital No. 1 named after Professor S.V. Ochapovsky with a diagnosis of meningioma of the right anterior oblique process. It was decided to perform a radical removal of the tumor with the imposition of an extra-intracranial anastomosis between the radial artery of the left arm and the right middle cerebral artery. After removal of the tumor, stenosis of the internal carotid artery was revealed, and therefore a temporary extraintracranial anastomosis was converted into a permanent shunt. The control MRI showed no signs of a residual tumor, and the cerebral blood flow was not compromised. The patient was discharged in a satisfactory condition.

Discussion. The involvement of the main cerebral arteries in the tumor node reduces the radical removal of neoplasms and reduces the duration of the recurrence-free period. The creation of a bypass arterial shunt is one of the methods of cerebral revascularization in the removal of tumors of the base of the skull with invasion into the main vessels of the brain. We used a technique that allows, at the stage of tumor removal, to provide temporary retrograde perfusion of the carotid basin arteries with the forced cessation of antegrade blood flow in them, and, if necessary, to perform permanent bypass bypass surgery of various volumes of blood flow in areas of the artery affected by the tumor.

Introduction. Effective hemostasis is crucial in neurosurgical operations at the tumor/brain interface, where classical methods of bleeding control may be insufficient. The widely used oxidized cellulose material (Surgicel®, one of the most popular materials used in our operating rooms) rarely causes granulomatous reactions that can mimic tumor recurrence or an abscess. Objective of the study was to review two clinical cases of an inflammatory reaction to a hemostatic agent with successful conservative treatment and to discuss the existing literature on this issue.

Materials and methods. We present the clinical cases of two patients (17 and 10 years old) who underwent neurosurgical operations using oxidized cellulose hemostatic agents, after which an inflammatory reaction to the material developed. In both cases, anti-inflammatory therapy with prednisolone was administered, leading to the complete regression of symptoms, including radiological findings.

Results. Both patients exhibited a typical clinical picture of an inflammatory reaction to the hemostatic material, confirmed by neuroimaging (MRI) and laboratory data. Anti-inflammatory treatment with prednisolone provided a rapid therapeutic effect, avoiding the need for reoperation.

Conclusions. A reaction to the hemostatic material, such as granulomatous inflammation, requires careful differential diagnosis from tumor recurrence and abscess. In stable cases, successful conservative treatment is possible, avoiding unnecessary surgical interventions.

The most common tumors of the cranial nerves are schwannomas. However, in rare cases, meningiomas that grow from arachnoid sheath оf cranial nerves may occur. Meningioma of the accessory nerve is an extremely rare pathology. In total, 6 cases of surgical removal of such tumors have been described in the literature to date. A 41-year-old woman consulted a neurosurgeon due to the presence of a tumor at the level of the craniovertebral junction, as well as its dynamic increase in size. According to magnetic resonance imaging, an intradural extramedullary lesion was detected at the level of the C1 vertebra on the right side, with intensive contrast enhancement. The patient underwent surgery, during which two tumors growing from the sheaths of the root of the right accessory nerve were visualized. Both tumors were removed totally, the histological and immunohistochemical analysis revealed an angiomatous meningiomas (WHO Grade I). The postoperative period was uneventful and the patient was discharged on the fourth day in a satisfactory condition.

Conclusion. Meningioma of sheaths of accessory nerve is a rare pathology, in the literature there are only isolated descriptions of the removal of this tumor. This clinical case is unique in that two meningiomas were located on the root of the accessory nerve.

Trigeminal neuralgia (TN) is a severe chronic condition that significantly impacts patients’ quality of life. The article reviews modern standardized approaches to neuroimaging in TN aimed at improving diagnostic accuracy. It proposes the implementation of a unified MRI protocol incorporating specialized sequences for detailed assessment of trigeminal nerve structures and detection of neurovascular conflict. The paper describes an image analysis algorithm focused on targeted evaluation of key anatomical areas and highlights the benefits of using clinically oriented structured reporting templates. Standardization of imaging methods helps reduce variability in data interpretation and enhances the quality of diagnosis and treatment for patients with TN.

Introduction. Syringomyelia is a chronic progressive disease of the nervous system characterized by the formation of cavities within the spinal cord. Idiopathic syringomyelia, which is associated with the development of spinal cord cavities without an apparent cause, is of particular interest. This article describes a clinical case of syringomyelia where determining the etiology proved to be significantly challenging, to the extent that it could have been classified as idiopathic.

Aim of the study. To present a diagnostically complex case of syringomyelia for discussion and to propose a diagnostic approach for situations where verifying the cause is difficult.

Case description. The paper presents a clinical case of a patient who was admitted to the Irkutsk City Clinical Hospital No. 3 in January 2023. The patient’s complaints included severe progressive weakness in the legs (more pronounced on the left), moderate weakness in the arms, decreased sensation in the lower half of the body (more pronounced on the right), impaired temperature sensitivity on the back and abdomen, increased urinary frequency, and weakness in the left arm since December 2022. Over several years of seeking medical help, magnetic resonance imaging (MRI) and contrast-enhanced MRI had been performed repeatedly but failed to identify the cause of the disease. A comprehensive examination was conducted, including contrast-enhanced multispiral computed tomography with myelography, which revealed a blockage of contrast agent propagation in the posterior spinal subarachnoid space. Surgical treatment was performed, involving laminectomy of Th_III–Th_VI and microsurgical removal of a space-occupying lesion in the spinal canal at the Th_III–Th_V level using intraoperative ultrasound navigation. The postoperative course was uneventful, with regression of neurological symptoms noted. The follow-up period was over 3 months with a favorable outcome. Histological examination determined that the cause of syringomyelia in patient A. was a Grade 1 meningothelial meningioma, which did not accumulate contrast agent.