Александр Владиславович Природов

Aim: to evaluate influence of robotic manipulator calibration accuracy and the spatial configuration of calibration points on the resulting target-point localization accuracy in a robot-assisted surgical navigation system. Material and methods. We conducted an experimental study with the use of an anthropomorphic head phantom made of polyethylene terephthalate glycol (PETG) using FDM. The phantom contained nine fiducial markers and an integrated measurement unit equipped with a monocular optical system. For the study we used integration of a collaborative robotic manipulator (REDS-C10) with a surgical navigation system (Autoplan). The research conducted a complete factor experiment investigating the relative accuracy impact of spatial configuration points (7 calibration configurations A–G of differing number of points and calibrator plans) rated for three calibration options (standard calibration, calibration with a prescribed calibration needle length error of +0.5 mm and calibration with incorrectly determined calibration point positions) and two surgical approaches (90° and 45° relative to the horizontal plane trajectories). A total of 5 repetitions were performed for each case, amounting to 210 measurements in all. The biopsy needle (1.9-mm-diameter) deviation from the aiming point was determined by pixel-based image analysis (pixel size: 0.029 mm). The vertical and horizontal components were measured separately. We used the Kruskal–Wallis and Mann–Whitney U tests with Holm correction to compare the results. Paired comparisons of the components were performed using the Wilcoxon signed-rank test. Results. Under standard calibration, the deviation was 0.81 (0.40) mm (95% CI, 0.71–0.90), compared with 1.21 (0.44) mm for a calibration needle length error and 1.72 (0.54) mm for incorrectly determined calibration point positions (H = 84.7; p 0.001; ε² = 0.40; all pairwise comparisons, p 0.001). The proportions of measurements exceeding the clinically acceptable threshold of 2 mm were 0%, 1.4%, and 30.0%, respectively. The two types of calibration error differed in the direction of the resulting deviation. A needle length error produced predominantly horizontal deviation (1.12 [0.43] vs. 0.35 [0.31] mm; p 0.001), whereas errors in calibration point determination resulted in an approximately isotropic deviation (1.09 [0.53] and 1.19 [0.60] mm; p = 0.25). The calibration point configurations also differed significantly under standard calibration (p 0.001). Configuration B yielded the smallest relative increases in deviation (+42.4% and +56.3%) while maintaining no measurements exceeding 2 mm. Conclusions. Calibration quality is an independent determinant of accuracy in robot-assisted surgical navigation. Incorrect determination of calibration point positions has a greater effect on accuracy than a calibration needle length error. The direction of the bias is specific to the type of calibration error and may be used to detect errors during calibration quality control. A uniform distribution of 12 calibration points across the four calibrator planes provides an optimal compromise between baseline accuracy and robustness to calibration errors.

Профилактика развития дизрезорбтивной шунтзависимой гидроцефалии у пациентов после разрыва артериальных аневризм сосудов головного мозга

Introduction Symptomatic cerebral vasospasm (CVS) is one of the most severe complications of subarachnoid hemorrhage (SAH) due to ruptured cerebral aneurysms, leading to delayed cerebral ischemia. The pathogenesis of CVS is associated, among other factors, with a deficiency of the endothelial vasorelaxant factor — nitric oxide (NO). Administration of inhaled NO can replenish this deficit and help reduce the severity of CVS; however, clinical data remain limited. Aim To evaluate the feasibility of inhaled nitric oxide (iNO) therapy in patients with signs of symptomatic vasospasm in the acute period of non-traumatic SAH caused by ruptured cerebral aneurysms. Material and methods A case series was carried out involving 9 patients (5 women, 4 men; aged 35–74 years) admitted to the N.V. Sklifosovsky Research Institute for Emergency Medicine in 2022–2024 during the hyperacute period after cerebral aneurysm rupture. The main inclusion criterion was the development of symptomatic CVS resistant to standard therapy (calcium channel blockers, induced hypertension) for at least 1 hour. All the patients underwent microsurgical aneurysm clipping. Inhalation of NO was performed via a face mask using a “Tianox” device at a concentration of 55–80 ppm with FiO₂ 21% until regression of symptoms. Clinical neurological status, jugular venous oximetry, markers of oxidative stress (malondialdehyde (MDA), total antioxidant status (TAS)) and endogenous vascular regulation (nitric oxide metabolites (NOx), angiotensin-converting enzyme (ACE)), video-EEG monitoring and CT perfusion data were assessed. Results Inhalation therapy resulted in regression of symptomatic CVS in 8 of 9 patients, including complete neurological recovery in 5 patients. The mean time to symptom regression ranged from 3 to 21 hours. In 2 patients, premature discontinuation of therapy led to symptom recurrence, requiring resumption of inhalations. CT perfusion on day 7 revealed reversible focal cerebral perfusion deficits in 4 patients. No adverse effects (methemoglobinemia >3.5%, hypotension, toxic NO₂ concentrations) were recorded. Mortality (n=2) was due to extracranial complications. Conclusion Inhaled NO therapy in SAH patients with symptomatic CVS on spontaneous breathing is safe and potentially effective for rapid regression of neurological symptoms and improvement of cerebral perfusion.

Introduction. Non-traumatic subarachnoid hemorrhage (SAH) due to ruptured cerebral aneurysms remains one of the most severe forms of acute cerebrovascular disease with a high risk of delayed cerebral ischemia. One of the key pathogenetic mechanisms in this pathology is severe impairment of endogenous regulation of vascular tone and the development of oxidative stress. Inhaled nitric oxide therapy is considered a potential method for modulating vascular tone and reducing the risk of vasospasm. The aim of the study. Was to evaluate the effect of inhaled nitric oxide therapy on the severity of oxidative stress and endogenous factors involved in regulation of vascular tone in patients with acute non-traumatic SAH due to ruptured cerebral aneurysms. Materials and methods. The study included 57 patients with acute SAH hospitalized at the N.V. Sklifosovsky Research Institute for Emergency Medicine between 2020 and 2025. The study group consisted of 25 patients receiving inhaled nitric oxide therapy (50–80 ppm, 3–24 hours per day, 4–7 days postoperatively); the comparison group consisted of 32 patients without this therapy. Inclusion criteria: massive basal hemorrhage, aneurysm clipping within the first 72 hours, and Hunt-Hess stage II–IV. Levels of malondialdehyde (MDA), total antioxidant activity, stable nitric oxide (NOx) metabolites, angiotensin-converting enzyme (ACE), glucose, and lactate dehydrogenase (LDH) were assessed in serum and cerebrospinal fluid. Statistical analysis was performed using the Mann-Whitney U test, with a significance level of pResults. In patients receiving therapy, serum NOx levels increased statistically significantly at all observation periods (pConclusions. Inhaled nitric oxide therapy helps restore the balance of endogenous factors involved in regulation of vascular tone without increasing oxidative stress and ischemic damage. This method can be considered as an additional component of complex therapy, but requires further study.

Background. Treatment of patients with combined injury and unstable sacral fractures is a complex interdisciplinary problem due to high risks of mortality and neurological complications, and long rehabilitation. The study is important because of the absence of a consensus on the optimal time and technique of surgical stabilization, as well as on further treatment of patients with unstable sacral fractures. Aim. To analyze results of treatment of patients with unstable sacral fractures (type С per the Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification). Materials and methods. The retrospective study included 67 patients aged 18 to 65 years with diagnosis of unstable sacral fracture (2014–2023). Depending on treatment tactics, 2 groups were identified: group 1 received surgical treatment ( n = 54) with subgroup 1А undergoing sacroiliac fixation ( n = 26), group 1B – triangular fixation ( n = 25), group 1В – sacral canal decompression ( n = 3); group 2 received conservative treatment ( n = 13). Assessment of treatment efficacy included analysis of the following parameters: time to mobilization, complications, functional outcomes (Majeed scale), neurological status (Gibbons scale). Results. Time to mobilization in the group 1 (surgical treatment) was 6.2 ± 3.8 days (subgroup 1А), in the group 2 (conservative treatment) – 31.4 ± 8.3 days ( p Conclusion. The maximal efficacy in treatment of type C3 per AO classification complicated sacral fractures was achieved using triangular fixation technique which allowed to achieve the best neurological outcomes. For uncomplicated fractures, isolated sacroiliac fixation showed excellent results. Conservative treatment is associated with high risk of complications and is the last choice.

Background. Invasive monitoring of electrical activity of the brain (invasive electroencephalography (EEG)) can have a number of advantages in diagnosis of early damage and delayed ischemia of the brain during cerebral vascular spasm due to its higher sensitivity and lower number of artifacts compared to noninvasive (scalp) monitoring. However, there are no standards of invasive electrode placement and registration of invasive recording. We present clinical experience of invasive prolonged EEG monitoring in patients during the acute period of cerebral aneurysm rupture.Aim. To develop technique of invasive EEG monitoring in patients with cerebral aneurysm rupture and to evaluate characteristics of the observed electrographic changes.Materials and methods. Series of clinical observations are presented: 6 patients who were operated on in the acute period of nontraumatic subarachnoid hemorrhage and who underwent simultaneous scalp and invasive EEG monitoring.Results. Pathologic changes observed during EEG correlated with development of areas of cerebral ischemia. Changes registered during invasive EEG were more pronounced and appeared earlier than during scalp monitoring.Conclusion. Informativity of invasive EEG monitoring in diagnosis of delayed cerebral ischemia and seizureless epileptiform activity is higher compared to scalp EEG monitoring.

INTRODUCTION The main reasons for the unsatisfactory outcome of surgical treatment of patients with non-traumatic subarachnoid hemorrhage (SAH) due to ruptured cerebral aneurysms are vascular spasm (VS) and delayed cerebral ischemia. Lysis of blood clots in the subarachnoid space leads to the release of a large number of various vasoactive factors that stimulate cytotoxic, inflammatory reactions and oxidative stress, which may be one of the reasons for the development of VS and secondary ischemic brain damage.THE AIM OF THE STUDY Study of the dynamics of oxidative stress indicators and factors of endogenous vascular regulation in patients with non-traumatic SAH due to ruptured cerebral aneurysms.MATERIAL AND METHODS A total of 80 patients in the acute period of SAH due to ruptured cerebral aneurysms were treated and examined. The average age of the patients was 51.7 years. The control group (norm) included 25 practically healthy people, whose average age was 32.7±8.6 years. The study used the blood serum and cerebrospinal fluid of the patients. The study points were 0, 1, 3, and 7 days after the patient’s admission to the hospital. The severity of oxidative stress was assessed by the level of malonic dialdehyde (MDA) and total antioxidant activity of blood serum (TAA); vasotonic function of vascular endothelium by the content of stable metabolites of nitric oxide (NOx) and the concentration of angiotensin-converting enzyme (ACE). Biochemical studies were carried out on the biochemical analyzer “Olympus AU 2700” (Beckman Coulter, USA).RESULTS It was revealed that patients with SAH already had pronounced oxidative stress upon admission to the hospital (increased MDA level, decreased TAA level), which led to an imbalance in the endogenous regulation of vascular tone (decreased NOx level, increased ACE concentration) and increased by the 7th day after admission to the hospital. High lactate dehydrogenase (LDH) activity was observed, the peak of which was on the 7th day of observation. Determination of LDH activity may be promising as a biomarker of ischemic brain injury and a prognostic indicator of the development of an unfavorable outcome.CONCLUSIONS The obtained data indicate the need for a comprehensive approach to the treatment of patients with subarachnoid hemorrhage. The most relevant therapeutic goal is the removal of blood from the subarachnoid space of the brain to prevent increased oxidative stress and angiospasm.

Secondary vascular spasm due to non-traumatic rupture of cerebral artery aneurysms is a formidable complication leading to serious disability of patients who face this disease, and in 30–50% of cases leads to death. Standard therapy used in intensive care units does not have tremendous success in the treatment of this pathology, which encourages scientists around the world to search for new drugs that can improve the outcome and increase the quality of life of patients. At the moment, the most promising non-surgical method of treatment is the use of nitric oxide donor drugs as part of complex therapy. In modern medicine, there are several ways to administer drugs of this group: intravenously, intra-arterially , intrathecally , intraventricularly and by inhalation . The method depends on the type of drug used. Despite the promise of using these dosage forms, there are a number of negative side effects, which, due to insufficient study, limit their widespread use in hospitals. This review contains studies examining the positive and negative aspects of the use of these drugs and the appropriateness of their use.

Intensive care of patients with acute non-traumatic subarachnoid hemorrhage primarily relies on diagnostics of delayed cerebral ischemia (DCI). The major difficulty in detecting DCI emerges upon suppression of wakefulness, when clinical assessment of growing neurological deficit becomes complicated. Widely used transcranial dopplerography allows solely to verify a vasospasm development not always leading to DCI exhibiting a multifactorial underlying mechanism. Electroencephalography (EEG) is the only broadly available instrumental tool ensuring a continuous monitoring of cerebral functional status including in subjects at intensive care unit. To date, non-specific EEG parameters pointing at development of acute cerebral injury were identified that provide varying diagnostic and predictive informative value in DCI. We reviewed publications aimed at assessing the data on visual and quantitative EEG parameters such as regional slowing, alpha rhythm spectral power and relative variability, alpha-to-delta power ratio, and detection of epileptiform activity. Having searched international and Russia-wide medical databases, we found only 7 publications quantitatively assessing diagnostic value of EEG monitoring, which showed that for DCI diagnosis its sensitivity ranged from 76% to 100%, and specificity – from 54% to 100%. We also present a clinical case with a 70-year-old female patient who underwent surgery for non-traumatic subarachnoid hemorrhage due to a ruptured aneurysm of the communicating segment of the right internal carotid artery. During the continuous videoEEG monitoring 2 days before clinical deterioration and appearance of ischemic changes in the right cerebral hemisphere on computed tomography scans, an ictal-interictal continuum pattern was noted to emerge. Future studies should be aimed at clarifying and validating the most informative DCI biomarkers including while recording EEG with intracranial electrodes that may contribute to development of automated algorithms for DCI detection.

RELEVANCE. One of the problems complicating the early postoperative period in patients with supratentorial meningiomas is epileptic seizures, which in 9-16% of cases first develop within the first 7 days after tumor removal (acute symptomatic epileptic seizures).AIM OF THE STUDY. To identify risk factors for the occurrence of acute symptomatic epileptic seizures in the early postoperative period in patients with supratentorial meningiomas and to evaluate the effectiveness of prophylactic antiepileptic therapy.MATERIAL AND METHODS. A prospective, single-blind, randomized, placebo-controlled study was conducted using the sequential, alternate-arm randomization method. The treatment of 102 patients with supratentorial meningiomas was analyzed, in whom the tumor was removed between 01.01.2021 and 30.09.2023 at the N.V. Sklifosovsky Research Institute for Emergency Medicine. To identify risk factors for the development of acute symptomatic epileptic seizures in patients, we assessed the data of the anamnesis, examination of the patient, electroencephalography before surgery, neuroimaging before and after tumor resection, as well as the characteristics of the intraoperative period, duration and outcomes of hospitalization. To evaluate the effectiveness of the prophylactic use of antiepileptic drugs, patients were divided into two groups. The first group consisted of 49 patients who took an antiepileptic drug as a prophylaxis of early epileptic seizures. The second group consisted of 53 patients who took a placebo drug. Both groups were divided into two subgroups each depending on the development of an epileptic seizure or its absence after surgery. In the first group, patients with epileptic seizures were considered the main subgroup, the patients without seizures were considered the control. We assessed the placebo group similarly.RESULTS. In the placebo group, a risk factor for the development of acute symptomatic epileptic seizures was the transection of one or more veins, which was necessary to achieve sufficient surgical access, leading to a change in cerebral venous blood flow (p=0.013, odds ratio (OR)=11.43; 95% CI [1.75–74.73]). In both the antiepileptic drug group and the placebo group, risk factors included an increase in the volume of cerebral edema according to postoperative CT scan data compared with preoperative (p=0.05, OR=18.8; 95% CI [2.0–182.7] and p=0.01, OR=12.6; 95% CI [2.36–68.0], respectively), as well as hemorrhagic transformation of the perifocal edema zone (p=0.03, OR=8.75; 95% CI [1.36–56.4] and p=0.02, OR=9.7; 95% CI [2.1–44.6], respectively). The efficacy of prophylactic use of antiepileptic drugs in reducing the incidence of acute symptomatic epileptic seizures in the first 7 days after surgery was not established (p=0.295, OR=0.533; 95% CI [0.181–1.572]).CONCLUSION. We have identified the following risk factors for the development of acute symptomatic epileptic seizures: an increase in the volume of cerebral edema compared to the preoperative level according to postoperative computed tomography, the development of hemorrhagic transformation of cerebral edema in both groups, and the intersection of one or more veins during surgery (in the placebo group). Confirmation of the efficacy of routine use of antiepileptic drugs for the prevention of acute symptomatic epileptic seizures not received.