Theodosis Kalamatianos

Background/Objectives: Trochlear nerve palsy (TNP) is a clinically significant neuro-ophthalmic disorder with a broad and heterogeneous etiologic spectrum. Due to the trochlear nerve (TN)’s long intracranial course and its proximity to key neurosurgical corridors, it is particularly susceptible to injury. This systematic review aimed to synthesize contemporary evidence on TNP etiologies and highlight diagnostic considerations. Methods: Following PRISMA 2020 guidelines (PROSPERO registration: CRD420251150614), we systematically searched PubMed through July 2025 for studies reporting TNP etiologies. Given substantial heterogeneity in study populations and methodologies, a qualitative synthesis was performed examining study characteristics, patient demographics, etiological distribution, and clinical outcomes. Results: Thirty-three studies (n = 5785) met the inclusion criteria. Reported etiologies clustered into seven categories: congenital, vascular/ischemic, infectious/inflammatory, structural, traumatic, iatrogenic, and idiopathic. Congenital cases frequently demonstrated absence of the TN or superior oblique hypoplasia. Microvascular ischemia predominated in older adults with vascular risk factors and typically exhibited spontaneous recovery. Structural lesions (e.g., tumors, aneurysms) and trauma were major acquired causes, often associated with more persistent deficits. Iatrogenic palsy predominantly followed skull base and petroclival procedures; most cases resolved, although lasting dysfunction occurred after complex or radiosurgical interventions. A proportion of cases remained idiopathic, and many resolved spontaneously. Conclusions: TNP displays a broad etiologic spectrum with distinct clinical profiles and prognostic trajectories. Accurate etiologic classifications supported by targeted neuroimaging and focused clinical evaluation are essential for optimizing management and informing neurosurgical decision-making.

Colorectal cancer is a significant health concern that can often be prevented through early detection of precancerous polyps during routine screenings. Although artificial intelligence (AI) methods have shown potential in reducing polyp miss rates, clinical adoption remains limited due to concerns over patient privacy, limited access to annotated data, and the high cost of expert labeling. To address these challenges, we propose an unsupervised domain adaptation (UDA) approach that leverages a fully synthetic colonoscopy dataset, SynthColon, and adapts it to real-world, unlabeled data. Our method builds on the DAFormer framework and integrates a Transformer-based hierarchical encoder, a context-aware feature fusion decoder, and a self-training strategy. We evaluate our approach on the Kvasir-SEG and CVC-ClinicDB datasets. Results show that our method achieves improved segmentation performance of 69% mIoU compared to the baseline approach from the original SynthColon study and remains competitive with models trained on enhanced versions of the dataset.

Savvas Melissanidis*, George Triantafyllou*, George Botis, Konstantinos Natsis, Katerina Vassiou, Marianna Vlychou, George Tsakotos, Theodosis Kalamatianos, Nikolaos Lazaridis, George Matsopoulos, Maria Piagkou. Anat Cell Biol -0001;0:. https://doi.org/10.5115/acb.24.249

Background: The vestibular Romberg test, which assesses the deterioration of balance while standing on rubber foam with closed eyes, is a well-established method in the physical neurological assessment of patients with peripheral vestibulopathy. This study aims to determine whether it can differentiate peripheral vestibulopathy from its main differential diagnosis, namely sensory ataxia, as both conditions typically present with a positive classical Romberg test. Methods: Static balance was assessed in three groups: patients with peripheral vestibulopathy, patients with pure sensory neuropathy, and healthy age-matched controls. Participants stood quietly on a force platform under varying visual and proprioceptive feedback conditions. Conventional and advanced postural sway metrics were investigated to establish a quantitative analogy to both the clinical Romberg and vestibular Romberg tests. Results: Posturographic analysis revealed that, in contrast to healthy controls, patients with vestibular disorders exhibited higher vestibular Romberg quotient values. However, the classical vestibular Romberg quotient did not show diagnostic discrimination between vestibulopathy and sensory neuropathy patients. This lack of discrimination was mainly due to the increased body sway observed in all patient groups under the “eyes open” condition. Nevertheless, a refined vestibular Romberg quotient—comparing standing on foam versus standing on firm support with eyes closed—was able to reliably distinguish vestibulopathy from sensory ataxia. This distinction was evident in both conventional linear sway and spectral postural sway metrics. Conclusions: We conclude that a refined Romberg test, performed solely under conditions of visual deprivation, offers valuable classification potential in differentiating peripheral vestibulopathy not only from healthy controls but also from patients with disequilibrium due to sensory loss.

Background: Cognitive resilience is a critical factor in high-performance environments such as military operations, where sustained stress can impair attention and decision-making. In the present study, we utilized EEG and machine learning to assess cognitive resilience in elite military personnel. Methods: For this purpose, EEG signals were recorded from elite military personnel during stress-inducing attention-related and emotional tasks. The EEG signals were segmented into two temporal windows corresponding to the initial stress response (baseline) and the adaptive/recovery phase, extracting power spectral density features across delta, theta, alpha, beta, and gamma bands. Different machine learning models (Decision Tree, Random Forest, AdaBoost, XGBoost) were trained to classify temporal phases. Results: XGBoost achieved the highest accuracy (0.95), while Shapley Additive Explanations (SHAP) analysis identified delta and alpha bands (particularly in frontal and parietal regions) as key features associated with adaptive mental states. Conclusions: Our findings indicate that resilience-related neural responses can be successfully distinguished and that interpretable AI frameworks can be used for monitoring cognitive adaptation in high-stress environments.

Background: The morphology of the occipital condyles (OCs) and foramen magnum (FM) is critical for neurosurgical planning and forensic identification. However, pooled reference values and the impact of study-level moderators on morphometric estimates remain underexplored. Methods: A systematic review and meta-analysis were conducted to estimate pooled morphometric values of the OCs and FM. Databases were searched for studies reporting relevant data in adult human subjects. A random-effects model was used to calculate pooled means and mean differences (MDs) by sex and side (left vs. right). Risk of bias and study quality were assessed. Subgroup analyses were conducted based on study design (osteological vs. imaging) and geographical region. Meta-CART (classification and regression trees) was used to explore moderator interactions and identify data-driven subgroups contributing to heterogeneity. Results: A total of 61 studies comprising 8010 adult skulls met the inclusion criteria. Substantial heterogeneity was observed across studies; most were assessed as having low-to-moderate methodological quality and a high risk of bias. The pooled mean values were as follows: OC length (OCL): 21.51 mm, OC width (OCW): 11.23 mm, OC thickness (OCT): 9.11 mm, FM length (FML): 35.02 mm, and FM width (FMW): 28.94 mm. Morphometric values reported in imaging-based studies were consistently lower than those from osteological studies. Evident sexual dimorphism was identified, with males exhibiting larger dimensions than females. The most pronounced sex-based mean differences (MDs)—approximately 2 mm—were found in OCL, FML, and FMW. In contrast, differences in OCT and OCW were under 1 mm. No significant side-related asymmetries were observed overall. Subgroup analysis revealed that sex-related MDs were more prominent in imaging studies, particularly for the right OCL and OCW. Meta-CART analysis identified study design as the strongest moderator for OCL, OCW, and FML. Sexual dimorphism was more pronounced in imaging studies but statistically insignificant in osteological samples. Furthermore, sex emerged as a stronger predictor for OCL than OCW, while geographical region had a greater impact on OCW. For OCT, geographical region was the main influencing factor, whereas sex was the primary moderator for FMW. Conclusions: OC and FM morphometry exhibit substantial heterogeneity across studies. Imaging-based methods more effectively detect sex-related differences, underscoring their utility in forensic identification and neurosurgical planning. These findings emphasize the need for more standardized, high-quality morphometric research to support population-specific anatomical reference data.

Purpose: This meta-analytical systematic review aims at investigating the variability of the pterion, focusing on its morphological types and precise distances from various bony landmarks. Additionally, the neurosurgical significance of this critical cranial landmark is examined in depth. Methods: The systematic review was conducted following PRISMA 2020 and Evidence-based Anatomy Workgroup guidelines for anatomical studies. The risk of bias was assessed using the Anatomical Quality Assurance Tool (AQUA). The meta-analysis was performed using R programming software and RStudio, employing the “meta” and “metafor” packages. Results: A total of 79 studies were included, encompassing 18,694 skull sides. The sphenoparietal type was identified as the most prevalent pterion variant, with a pooled prevalence of 78.54%. The epipteric type followed at 8.41%, while the frontotemporal (5.74%) and stellate (4.26%) types were the rarest. Significant differences in the prevalence of the epipteric, frontotemporal, and stellate types were observed across different nationalities. However, sex, side, and study type did not significantly influence pterion morphological variation. The study also extracted and calculated the distances between the pterion and key anatomical landmarks, including the midpoint of the zygomatic arch, the frontozygomatic suture, the mastoid process, and the external acoustic meatus. Conclusion: This study offers critical anatomical insights by accurately mapping the pterion’s location relative to essential cranial landmarks. These findings are vital for neurosurgical planning, particularly for procedures involving the anterior and middle cranial fossae. The detailed anatomical data provided can enhance the precision and safety of neurosurgical interventions, ultimately improving patient outcomes.

This study aimed to conduct a bibliometric analysis of the 100 most cited articles on experimental cardiac arrest models in rats, identifying key contributors, publication trends, research themes, and collaboration networks. A comprehensive literature search was performed on the Web of Science (WoS) database on June 11, 2024, using keywords related to cardiac arrest and rat models. The top 100 most cited articles were analyzed using the Biblioshiny web application from the Bibliometrix R package (version 4.2.3), categorized by primary research focus. Articles, published from 1980 to 2022, involved 416 authors across 44 journals, averaging 106.7 citations each. Primary research themes were neurology (72%), organ transplantation (7%), cardiovascular system (6%), CPR outcomes after local anesthetic toxicity (4%), and other topics (5%). The United States, Japan, and Germany were leading contributors, with limited international collaborations. Major clusters identified included "Cerebral Ischemia and Outcomes," "Brain Imaging Metrics," and "Blood Brain Barrier". The most commonly used methodologies for cardiac arrest induction were asphyxia, induction by magnesium or potassium chloride and electrical stimulation. This first bibliometric analysis on the topic reveals a dominance of neuroscience in experimental cardiac arrest models in rats. High-impact journals like the "Journal of Cerebral Blood Flow and Metabolism" play critical roles in disseminating significant research. The study highlights substantial gaps in global research engagement, with minimal contributions from lower-income countries and few international collaborations. This analysis provides a roadmap for future research directions and opportunities for more extensive international and interdisciplinary collaboration, always with a focus on scientific rigor.

Purpose The paracentral lobule artery (PLA) is a typically present branch of the distal anterior cerebral artery (ACA), irrigating the homonymous lobule. The PLA origin is either a pericallosal portion of the ACA or a prominent branch of the ACA termed callosomarginal (CMA). In addition to the paracentral lobule, the PLA irrigates the cingulate gyrus in the medial hemispheric surface, and the superior portion of the precentral and postcentral gyri in the lateral hemispheric surface. The present cadaveric case series aimed at establishing previously unreported morphometric estimates of the PLA, including its length according to its site of origin, its supplying branches according to its distribution area, as well as its anastomoses. Methods Seventeen colored latex-injected cadaveric heads were studied with a surgical microscope and microsurgical instruments. Results The PLA was invariably present and most commonly originated from the A4 (n = 15 hemispheres, 50%) segment of the ACA. Other PLA origins were the CMA (n = 10, 30%), the A3 (n = 5, 16.7%) and the A5 (n = 1, 3.3%) segments. When the PLA originated from the A4, its mean (SD) overall length was 7.6 (17.9) mm and its mean (SD) diameter was 0.88 (0.26) mm. The PLA supplied the paracentral lobule, cingulate gyrus and post central gyrus with a mean (SD) of 28.07 (13.4), 8.53 (4.27), 5.92 (4.4) branches respectively and the precentral gyrus with a median [IQR] of 2 [0–6] branches. The most common anastomoses of the PLA in the medial and the lateral hemispheric surface involved the ipsilateral posterior internal frontal artery and the branches of the middle cerebral artery, respectively. There were no significant differences between sexes or hemispheric sides for the anatomical features of the artery analyzed. Conclusion The present study established previously unreported morphometric estimates for the PLA by considering all possible PLA variant origins and morphological variants. Given that variable pathologies have been previously detected in the areas supplied by the PLA, a better understanding of its anatomy can aid surgical planning and approaches.