The endoscopic endonasal transsphenoidal approach (EETA) is recognized as an effective and safe method for the resection of pituitary and sellar/suprasellar tumors. Classified as a clean-contaminated procedure, EETA entails intraoperative exposure to the nasal cavity, thereby introducing a potential risk of contamination with Staphylococcus aureus. The procedure also involves the sphenoid sinus - an anatomical region whose microbiological profile is poorly characterized in the current literature. To determine microbial colonization patterns within the sphenoid sinus and their correlation with other anatomical sites for the preoperative identification of high-risk patients prior to EETA. This prospective study included patients who underwent EETA between December 2024 and February 2025. All patients underwent microbiological testing of nasopharyngeal swabs, sphenoid sinus mucosa biopsies, gastrointestinal tract specimens, and endotracheal aspirates obtained via the endotracheal tube. A cohort of forty-one patients with a mean age of 61 years, was enrolled in this study. Microbial colonization of the sphenoid sinus was highly prevalent, detected in 90
Background. Cerebral arteriovenous malformations (AVMs) are high-flow vascular anomalies that carry a considerable burden of haemorrhagic morbidity. Work over the past decade has shown that both inherited syndromes and apparently sporadic lesions can be traced to alterations in a handful of signalling pathways, but the relevant evidence sits awkwardly between human genetic studies, animal models, and molecular profiling experiments. Objective. To bring together the current evidence on the molecular and genetic underpinnings of cerebral AVM formation, clinical course, and candidate therapeutic targets. Methods. We searched MEDLINE (PubMed), Embase, Web of Science Core Collection, and Scopus from inception to 1 January 2026. Records were screened, and full texts assessed, by two reviewers working independently. Studies were eligible if they reported genetic, molecular, or epigenetic data on cerebral AVMs. Because of substantial heterogeneity in designs and outcomes, evidence was synthesised qualitatively. Results. Of 343 records, 44 primary studies (28 clinico-genetic and 16 experimental) together with 20 reviews and meta-analyses met inclusion. Inherited AVM syndromes largely reflected germline variants in the TGF-β/BMP network (ENG, ACVRL1, SMAD4, GDF2/BMP9) or in arteriovenous-specification regulators (RASA1, EPHB4); penetrance was incomplete and there was support for local modifying "second-hit" events. Resected sporadic cerebral AVMs often carried somatic activating mutations in the RAS/MAPK cascade—mostly KRAS, less often BRAF—at low variant allele fractions that demanded high-sensitivity assays. Endothelial-specific activation of KRAS or BRAF reproduced AVM-like phenotypes in vivo and showed MEK–ERK dependence. Susceptibility variants (notably at 9p21/ANRIL), inflammatory mediators, extracellular-matrix remodelling, and epigenetic changes appear to fine-tune lesion behaviour and haemorrhagic risk. Conclusions. Syndromic predisposition and clonal somatic events in endothelium converge on a small set of developmental signalling axes that govern angiogenesis and vessel-wall maturation. Diagnostics anchored in this biology, together with pathway-targeted therapy, now need prospective evaluation, paired with standardised approaches for detecting low-level mosaicism.
Background: Endoscopic endonasal surgery (EES) offers a direct ventral corridor to the skull base, potentially enabling maximal resection of extensive cholesteatomas (epidermoid cysts) in the posterior cranial fossa and parasellar region. However, outcomes and complications specific to this approach require detailed analysis. Methods: A retrospective review was conducted on 34 patients who underwent EES for cholesteatomas of the posterior fossa and parasellar region at a single high-volume center (2011-2025). Surgical approaches were tailored to the lesion's extent. Extent of resection (near-total >95%, subtotal 90-95%), complications, and neurological outcomes were analyzed. Results: Near-total resection was achieved in 65% of cases and subtotal in 35%. The most frequent complications were postoperative cerebrospinal fluid (CSF) leakage (23.5%) and meningitis (23.5%; 33.3% in patients with intradural extension). Rates were significantly higher than for other skull base tumors. Only visual symptoms showed consistent postoperative improvement. New or worsened cranial nerve deficits occurred in 12% of cases. The rates of CSF leakage and meningitis were 25% and 33%, respectively. Arrested hydrocephalus requiring shunting developed in 14.7% of patients. Conclusion: EES provides a valid alternative for the surgical management of posterior fossa and parasellar cholesteatomas, allowing for a high degree of resection. However, it is associated with a notably higher risk of CSF leakage and meningitis compared to EES for other pathologies, attributable to the lesion's adhesive and inflammatory characteristics. Furthermore, significant recovery of preoperative neurological deficits (except visual) is uncommon. These findings underscore that such complex procedures should be performed in specialized centers with extensive expertise in endoscopic skull base surgery and multidisciplinary perioperative care.
Background. Standard error matrices systematically underestimate the clinical value of diagnostic artificial intelligence (AI) tools by misclassifying cautionary conclusions regarding histologically benign, yet clinically suspicious neoplasms with clinical signs of malignancy as false-positive outcomes. Objective: To develop and validate a methodology for assessing the clinical effectiveness and accuracy of diagnostic AI tools in dermato-oncology, incorporating clinical caution alertness as an independent metric. Material and methods. A total of 342 skin lesions were evaluated at the Burdenko Main Military Clinical Hospital (2025–2026). While a standard error matrix was used or the formal accuracy assessment, the clinical evaluation relied on two newly developed: a four-category clinical effectiveness system (complete concordance, concordance in clinical caution, discordance in clinical caution, complete discordance), and a clinical accuracy formula derived from a clinical case matrix (Justified Conclusion, Unjustified Conclusion, Missed Justified Conclusion and Not Missed Justified Conclusion). Wilson confidence intervals (CIs) were applied. Results. The formal evaluation yielded an accuracy was of 89.7% (100.0% sensitivity, 84.8% specificity). The analysis of clinical effectiveness revealed complete concordance in 82.2% of cases, concordance in clinical caution in 12.9%, discordance in clinical caution in 1.2%, and complete discordance in 3.8%. Clinical accuracy metrics were as follows: 98.5% sensitivity (95% CI 94.6–99.6), 88.1% specificity (95% CI 83.0–91.8), 92.1% accuracy (95% CI 88.8–94.5). Conclusion. Relying solely on the formal diagnostic accuracy of AI tools underestimates their clinical value. The proposed clinical accuracy and effectiveness metrics ensure an objective assessment of AI tools in relation to the real-world tasks in dermatooncological patient routing.
Background: Virtual reality (VR) is actively used in medicine for surgeon training, allowing the practice of complex procedures without risk to patients. In neurosurgery, VR is particularly relevant for procedures such as external ventricular drainage (EVD) placement, which require high precision. The aim of this study was to develop a VR simulator for EVD placement and evaluate its effectiveness in training surgeons with different levels of experience. Methods: The simulator was developed using Meta Quest 3 VR headsets with motion tracking and controllers as well as Inobitec and Shapelab software for segmentation and 3D visualization based on computed tomography/magnetic resonance imaging data. The model included anatomical structures (skull, brain, and ventricles) and surgical tools (catheter, scalpel, and drill). This is a prospective cross-sectional simulation pilot with three expertise strata (experts, residents, and students). The study involved 15 surgeons (5 experienced, 5 residents, and 5 students) performing virtual EVD placement. The primary endpoint was the accuracy of catheter placement, assessed on a 6-point scale (I-VI) by a single independent expert who was blinded to the participant’s group. The secondary endpoints were the procedure time, the number of predefined error types (incorrect entry point, incorrect trajectory, etc.), error rates (the proportion of attempts in which at least one error was made), and the survey results. Results: Experienced surgeons completed the procedure faster (113.4 ± 116.4 s) and with fewer errors (6%) compared to residents (176.3 ± 118.0 s) and students (140.8 ± 178.6 s), who had a 28% error rate. The most common errors were incorrect catheter placement (36% of cases) and wrong entry point selection (24%). A postexperiment survey revealed that 14 out of 93% of participants reported a positive training effect and would recommend the simulator for routine practice. Conclusion: The study confirms that VR-based simulation of EVD placement is a feasible technique and shows evidence of construct validity. The technology allows surgeons to practice precision in a risk-free environment, reducing errors in real-world procedures. However, further research is needed to expand its clinical applications.
