A scarce combination of arterial variants: an occipital artery originating from the internal carotid artery associated with a linguofacial trunk.

The occipital artery (OA) typically originates from the external carotid artery (ECA). Variations of the ECA has been well described in the current literature, while the OA is a relatively stable vessel, and its variations are uncommon. In the current case report, an aberrant OA has been found coexisting with a linguofacial trunk (LFT) on the right hemineck of a 51-year-old male patient. The OA was identified originating from the cervical internal carotid artery (ICA) at the level of the second cervical vertebra (C2). On the ECA, the lingual and facial arteries were emanating in common, as LFT. The left hemineck of the patient was free of variations. The current coexistence of arterial variants has been reported only once previously; therefore, the current case corresponds to the second case in the English literature. The aberrant OA origin from the ICA has been estimated with a pooled prevalence of 0.37%, while the origin at the C2 level and from the anterior surface of the ICA corresponds to a very rare variation. Additionally, the LFT is one of the most common trunk that can be found on the ECA. Interventional radiologists and surgeons must be aware of common and uncommon variation to avoid iatrogenic lesion.

Romberg's test revisited: Changes in classical and advanced sway metrics in patients with pure sensory neuropathy.

OBJECTIVES: The Romberg test, undoubtedly a classical and well-established method in physical neurological assessment of patients with sensory ataxia, has long been suspected to be prone to several limitations. Here, we quantified upright stance before and after visual deprivation in a selected cohort of patients with pure sensory neuropathy. METHODS: Static balance was assessed in sensory neuropathy patients during quiet stance on a force platform under different visual and proprioceptive feedback conditions. Sural nerve neurography was employed to evaluate the severity of peripheral neuropathy. Conventional and advanced postural sway metrics were investigated to draw a quantitative analogy to the clinical Romberg test. RESULTS: Posturographic analyses showed that patients displayed Romberg and vestibular Romberg quotient values around 2, indicating an approximately twofold increase in body sway in the absence of vision. However, the diagnostic discrimination ability between patients and controls was only modest. Even less impactful were the diagnostic contributions of frequency domain and non-linear sway analyses. This was primarily attributed to the heightened body sway exhibited by patients with sensory neuropathy under 'eyes open' conditions, diminishing the contrast with the 'eyes closed' condition as assessed in the classical Romberg test. CONCLUSION: We conclude that the Romberg test, even in its quantitative form with the aid of an apparatus, had an unsatisfactory classification value in terms of distinguishing patients from healthy controls. Instead, it should be interpreted within the comprehensive context of the broader neurological examination and the electrodiagnosis of peripheral nerve function.

An ectopic thyrolingual trunk arising from the common carotid artery: a rare variant.

The common carotid artery (CCA) typically bifurcates into the external and internal carotid arteries (ECA and ICA). In the head and neck area, the ECA gives off a few anterior branches from proximal to distal: the superior thyroid artery (STA), the lingual artery (LA), and the facial artery (FA). Occasionally, these branches can fuse into trunks, with the linguofacial trunk being the most common. During a computed tomography angiography (CTA) of a 67-year-old patient, a common arterial trunk, 11.3 mm proximal (prior) to the CCA bifurcation was recorded. The trunk was formed by the STA and the LA fusion and was characterized as a thyrolingual trunk (TLT). These trunks have been reported with a prevalence ranging between 0.3 and 1% and correspond to one of the rarest variants of the ECA anterior branches. Knowledge of the typical and variant anatomy of the carotid arteries and their branches is of paramount importance to surgeons and interventional radiologists.

Over 30 Years of DiI Use for Human Neuroanatomical Tract Tracing: A Scoping Review.

In the present study, we conducted a scoping review to provide an overview of the existing literature on the carbocyanine dye DiI, in human neuroanatomical tract tracing. The PubMed, Scopus, and Web of Science databases were systematically searched. We identified 61 studies published during the last three decades. While studies incorporated specimens across human life from the embryonic stage onwards, the majority of studies focused on adult human tissue. Studies that utilized peripheral nervous system (PNS) tissue were a minority, with the majority of studies focusing on the central nervous system (CNS). The most common topic of interest in previous tract tracing investigations was the connectivity of the visual pathway. DiI crystals were more commonly applied. Nevertheless, several studies utilized DiI in a paste or dissolved form. The maximum tracing distance and tracing speed achieved was, respectively, 70 mm and 1 mm/h. We identified studies that focused on optimizing tracing efficacy by varying parameters such as fixation, incubation temperature, dye re-application, or the application of electric fields. Additional studies aimed at broadening the scope of DiI use by assessing the utility of archival tissue and compatibility of tissue clearing in DiI applications. A combination of DiI tracing and immunohistochemistry in double-labeling studies have been shown to provide the means for assessing connectivity of phenotypically defined human CNS and PNS neuronal populations.

The Anatomical Variation of the Distal Anterior Cerebral Artery: An Angiographic Study in a Greek Population Sample.

Objective The current retrospective angiographic study establishes the rates of variants in the distal anterior cerebral artery (DACA) in a sample of the Greek population. Methods Data were collected from 456 patients who underwent two-dimensional (2D) or three-dimensional (3D) digital subtraction angiography (DSA) of the carotid and vertebral arteries bilaterally. The study focused on patients with good visualization of the anterior and posterior circulations and employed magnetic resonance (MR) or computed tomography (CT) angiography for 3D reconstruction. The anterior cerebral artery (ACA) was classified into one of its two basic configurations, that is, with or without the callosomarginal artery (CMA). The bihemispheric, median, and azygos ACA patterns were also identified. Results The majority (373/456, 81.8%) exhibited a typical DACA pattern. The bihemispheric, median, and azygos patterns were identified in 66/456 (14.5%), 10/456 (2.2%), and 7/456 (1.5%), respectively. The CMA was present in 824/912 (90.4%) of the hemispheres, with a trend toward male predominance for bilateral presence (males: 167/192, 86.98%; females: 210/264, 79.55%; p = 0.05). In particular, the CMA was present significantly more frequently (p = 0.002) in the left hemispheres of male patients. Gender differences in CMA presence persisted in the analysis of the patients with a typical DACA pattern. Conclusion This study provides insights into the variations of the DACA in the Greek population. The observed gender differences in CMA rates suggest potential morphological variations in cerebral vasculature between males and females and contribute to a better understanding of vascular anatomy for clinical and surgical applications.

Parcellating the vertical associative fiber network of the temporoparietal area: Evidence from focused anatomic fiber dissections.

Introduction: The connectivity of the temporoparietal (TP) region has been the subject of multiple anatomical and functional studies. Its role in high cognitive functions has been primarily correlated with long association fiber connections. As a major sensory integration hub, coactivation of areas within the TP requires a stream of short association fibers running between its subregions. The latter have been the subject of a small number of recent in vivo and cadaveric studies. This has resulted in limited understanding of this network and, in certain occasions, terminology ambiguity. Research question: To systematically study the vertical parietal and temporoparietal short association fibers. Material and methods: Thirteen normal, adult cadaveric hemispheres, were treated with the Klinger's freeze-thaw process and their subcortical anatomy was studied using the microdissection technique. Results: Two separate fiber layers were identified. Superficially, directly beneath the cortical u-fibers, the Stratum proprium intraparietalis (SP) was seen connecting Superior Parietal lobule and Precuneal cortical areas to inferior cortical regions of the Parietal lobe, running deep to the Intraparietal sulcus. At the same dissection level, the IPL-TP fibers were identified as a bundle connecting the Inferior Parietal lobule with posterior Temporal cortical areas. At a deeper level, parallel to the Arcuate fasciculus fibers, the SPL-TP fibers were seen connecting the Superior Parietal lobule to posterior Temporal cortical areas. Discussion and conclusion: To our knowledge this is the first cadaveric dissection study to comprehensively study and describe of the vertical association fibers of the temporoparietal region while proposing a universal terminology.

The anterior communicating artery variants: a meta-analysis with a proposed classification system.

Morphological and morphometric variants of the anterior communicating artery (AComA) have been described by multiple studies; however, a complete classification system of all possible morphological variants with their prevalence is lacking. The current systematic review with meta-analysis combines data from different databases, concerning the AComA morphological and morphometric variants (length and diameter). Emphasis was given to the related clinical implications to highlight the clinical value of their knowledge. The typical AComA morphology occurs with a pooled prevalence (PP) of 67.3%, while the PP of atypical AComA is 32.7%. The identified AComA morphological variants (artery's hypoplasia, absence, duplication, triplication, differed shape, fenestration, and the persistence of a median artery of the corpus callosum- MACC) were classified in order of frequency. The commonest presented variants were the AComA hypoplasia (8%) and the anterior cerebral artery (ACA) fusion (5.9%), and the rarest ones were the MACC persistence (2.3%), and the AComA triplication (0.7%). The knowledge of those variants is essential, especially for neurosurgeons operating in the area. Given the high prevalence of AComA aneurysms, an adequate and complete classification of those variants is of utmost importance.

Anaplastic Lymphoma Kinase (ALK) in Posterior Cranial Fossa Tumors: A Scoping Review of Diagnostic, Prognostic, and Therapeutic Perspectives.

Anaplastic Lymphoma Kinase (ALK) has been implicated in several human cancers. This review aims at mapping the available literature on the involvement of ALK in non-glial tumors localized in the posterior cranial fossa and at identifying diagnostic, prognostic, and therapeutic considerations. Following the PRISMA-ScR guidelines, studies were included if they investigated ALK's role in primary CNS, non-glial tumors located in the posterior cranial fossa. A total of 210 manuscripts were selected for full-text review and 16 finally met the inclusion criteria. The review included 55 cases of primary, intracranial neoplasms with ALK genetic alterations and/or protein expression, located in the posterior fossa, comprising of medulloblastoma, anaplastic large-cell lymphoma, histiocytosis, inflammatory myofibroblastic tumors, and intracranial myxoid mesenchymal tumors. ALK pathology was investigated via immunohistochemistry or genetic analysis. Several studies provided evidence for potential diagnostic and prognostic value for ALK assessment as well as therapeutic efficacy in its targeting. The available findings on ALK in posterior fossa tumors are limited. Nevertheless, previous findings suggest that ALK assessment is of diagnostic and prognostic value in medulloblastoma (WNT-activated). Interestingly, a substantial proportion of ALK-positive/altered CNS histiocytoses thus far identified have been localized in the posterior fossa. The therapeutic potential of ALK inhibition in histiocytosis warrants further investigation.

GFAP and UCHL1 in Non-traumatic SAH: The Story thus Far. A Systematic Review of the Literature.

OBJECTIVE: Non-traumatic subarachnoid hemorrhage (SAH) is associated with a high percentage of misdiagnosis and poor prognosis. Biomarkers could be useful in the identification, treatment/management guidance, and outcome improvement of SAH patients. The current systematic review aims to investigate the potential role of biomarkers GFAP (Glial Fibrillary Acidic Protein) and UCH-L1 (Ubiquitin C-Terminal Hydrolase L1) in the diagnosis and prognosis of non-traumatic SAH. METHODS: A systematic search of PubMed, Scopus, and Web of Science databases was conducted from their inception through February 2023. RESULTS: 17 studies met the inclusion criteria and were included in this review. The vast majority of the included studies (82%) were on GFAP. Most studies used blood and/or CSF samples and incorporated multiple measurements through the initial hospitalization days. The majority of identified studies significantly reported higher levels of GFAP and UCHL1 in SAH patients with poor outcomes. There was notable variation in the specimen type and the timing of sampling. CONCLUSION: Quantification of GFAP and UCHL1 through the initial days of hospitalization shows promise in the prediction of SAH patient outcomes. Further research is nevertheless warranted to confirm these findings and further clarify the use of the two biomarkers in SAH diagnosis and the prediction of severity and secondary events.

The Landscape of Randomized Clinical Trial Meta-analyses on Statins for Aneurysmal Subarachnoid Hemorrhage: A Scoping Review.

INTRODUCTION: Aneurysmal subarachnoid hemorrhage (aSAH) is a type of non-traumatic SAH that can have detrimental effects on the central nervous system, resulting in severe disability or death. METHODS: Early nimodipine is currently the only strongly recommended pharmacological treatment that has shown efficacy in improving neurological/functional outcomes in aSAH patients. Whether statin treatment is of benefit to aSAH patients is an issue that has generated considerable interest and debate. In the present scoping review, we mapped and analyzed the available literature on metaanalyses of randomized clinical trials (RCTs) examining the effect of statins on aSAH. Seventeen meta-analyses of RCTs, published between 2008 and 2023, were identified. RESULTS: Treatments in included meta-analyses were based on various regimens of simvastatin, pravastatin, pitavastatin or atorvastatin for up to 21 days. Eleven of the included reports indicated some beneficial effect of statin treatment, reducing rates of at least one of the following: cerebral vasospasm, delayed cerebral ischemia/delayed ischemic neurologic deficit, mortality or functional/ neurological outcome. In contrast, six meta-analyses, showed no such effects. CONCLUSION: The limitations reported by several meta-analyses, included low patient numbers or disproportionate representation of patients from certain RCTs, differences in drug treatment, patient diagnostic criteria and outcome evaluation between RCTs, as well as poor data quality or lack of RCTs data. Knowledge of the reported limitations may aid the design of future clinical trials and/or their meta-analyses.

Advances on Liquid Biopsy Analysis for Glioma Diagnosis.

Gliomas comprise the most frequent primary central nervous system (CNS) tumors, characterized by remarkable genetic and epigenetic heterogeneity, difficulty in monitoring, and increased relapse and mortality rates. Tissue biopsy is an established method of tumor cell collection and analysis that enables diagnosis, classification of different tumor types, and prediction of prognosis upon confirmation of tumor's location for surgical removal. However, it is an invasive and often challenging procedure that cannot be used for frequent patient screening, detection of mutations, disease monitoring, or resistance to therapy. To this end, the minimally invasive procedure of liquid biopsy has emerged, allowing effortless tumor sampling and enabling continuous monitoring. It is considered a novel preferable way to obtain faster data on potential tumor risk, personalized diagnosis, prognosis, and recurrence evaluation. The purpose of this review is to describe the advances on liquid biopsy for glioma diagnosis and management, indicating several biomarkers that can be utilized to analyze tumor characteristics, such as cell-free DNA (cfDNA), cell-free RNA (cfRNA), circulating proteins, circulating tumor cells (CTCs), and exosomes. It further addresses the benefit of combining liquid biopsy with radiogenomics to facilitate early and accurate diagnoses, enable precise prognostic assessments, and facilitate real-time disease monitoring, aiming towards more optimal treatment decisions.

Biofluid Biomarkers in the Prognosis of Chronic Subdural Hematoma: A Systematic Scoping Review.

The present systematic scoping review aimed at mapping and analyzing the available literature on biological fluid (biofluid) biomarkers showing promise in the prediction of chronic subdural hematoma (cSDH) recurrence and the prognosis of neurological/functional patient outcome. Twenty-three studies published between 2003 and 2023 investigating a diverse range of biomarkers in hematoma fluid and/or the circulation in 3749 patients were included. Immune cell populations and inflammatory/anti-inflammatory cytokines comprised the most studied category of biomarkers displaying significant findings. A notable time trend in biomarker studies was a recent shift in research focus towards the analysis of circulating biomarkers. Several biomarkers were indicated as independent predictors of cSDH recurrence and/or functional/neurological outcome, including circulating fibrinogen degradation products (FDP), brain natriuretic peptide (BNP-1) and high-density lipoprotein (HDL), as well as blood urea nitrogen (BUN) and the ratios of blood neutrophil to lymphocyte (NLR) or red blood cell distribution width to platelet count (RPR). While studies on cSDH prognostic biomarkers have gained, in recent years, momentum, additional multicenter prospective studies are warranted to confirm and extend their findings. The identification of prognostic biofluid biomarkers in cSDH is an active field of research that may provide future tools, guiding clinical decisions and allowing for the design of treatments based on risk stratification.

Medial Pulvinar Stimulation in Temporal Lobe Epilepsy: A Literature Review and a Hypothesis Based on Neuroanatomical Findings.

While bilateral stimulation of the anterior thalamic nuclei remains the only approved deep brain stimulation (DBS) option for focal epilepsy, two additional thalamic targets have been proposed. Earlier work indicated the potential of centromedian thalamic nucleus stimulation with recent findings highlighting the medial pulvinar nucleus. The latter has been shown to exhibit electrophysiological and imaging alterations in patients with partial status epilepticus and temporal lobe epilepsy. On this basis, recent studies have begun assessing the feasibility and efficacy of pulvinar stimulation, with encouraging results on the reduction of seizure frequency and severity. Building on existing neuroanatomical knowledge, indicating that the medial pulvinar is connected to the temporal lobe via the temporopulvinar bundle of Arnold, we hypothesize that this is one of the routes through which medial pulvinar stimulation affects temporal lobe structures. We suggest that further anatomic, imaging, and electrophysiologic studies are warranted to deepen our understanding of the subject and guide future clinical applications.

Association between preoperative neurocognitive status and IDH1 mutation status in high-grade gliomas.

Background: High-grade glioma (HGG) patients present with variable impairment in neurocognitive function (NCF). Based on that, isocitrate dehydrogenase 1 (IDH1) wild-type HGGs are more aggressive than IDH1 mutant-type ones, we hypothesized that patients with IDH1 wild-type HGG would exhibit more severe NCF deficits than their IDH1 mutant counterparts. Methods: NCF was assessed by Mini Mental Status Exam (MMSE), Trail Making Test (TMT), Digit Span (DS), and Controlled Word Association Test (COWAT) tests in 147 HGG patients preoperatively. Results: Analyses between IDH1 groups revealed a significant difference on MMSE concentration component (p ≤ .01), DS (p ≤ .01), TMTB (p ≤ .01), and COWAT (p ≤ .01) scores, with the IDH1 wild group performing worse than the IDH1 mutant one. Age and tumor volume were inversely correlated with MMSE concentration component (r = -4.78, p < .01), and with MMSE concentration (r = -.401, p < .01), TMTB (r = -.328, p < .01), and COWAT phonemic scores (r = -.599, p < .01), respectively, but only for the IDH1 wild-type group. Analyses between age-matched subsamples of IDH1 groups revealed no age effect on NCF. Tumor grade showed nonsignificance on NCF (p > .05) between the 2 IDH1 mutation subgroups of grade IV tumor patients. On the contrary, grade III group showed a significant difference in TMTB (p < .01) and DS backwards (p < .01) between IDH1 subgroups, with the mutant one outperforming the IDH1 wild one. Conclusions: Our findings indicate that IDH1 wild-type HGG patients present greater NCF impairment, in executive functions particularly, compared to IDH1 mutant ones, suggesting that tumor growth kinetics may play a more profound role than other tumor and demographic parameters in clinical NCF of HGG patients.

Autotaxin Activity in Chronic Subdural Hematoma: A Prospective Clinical Study.

Autotaxin (ATX) is the ectoenzyme producing the bulk of lysophosphatidic acid (LPA) in circulation. ATX and LPA-mediated signaling (the ATX-LPA axis) play critical roles in the vascular and nervous system development. In adults, this axis contributes to diverse processes, including coagulation, inflammation, fibroproliferation and angiogenesis under physiological and/or pathophysiological conditions. Given evidence implicating several of these processes in chronic subdural hematoma (CSDH) pathogenesis and development, we assessed ATX activity in CSDH patients. Twenty-eight patients were recruited. Blood and hematoma fluid were collected. Enzymatic assays were used to establish serum and hematoma ATX activity. Enzyme-linked immunosorbent assays were used to establish hematoma beta trace (BT) levels, a cerebrospinal fluid (CSF) marker, in a hematoma. ATX activity was nearly three folds higher in hematoma compared to serum (P < 0.001). There was no significant correlation between BT levels and ATX activity in a hematoma. The present results show, for the first time, that ATX is catalytically active in the hematoma fluid of CSDH patients. Moreover, our findings of significantly elevated ATX activity in hematoma compared to serum, implicate the ATX-LPA axis in CSDH pathophysiology. The CSF origin of ATX could not be inferred with the present results. Additional research is warranted to establish the significance of the ATX-LPA axis in CSDH and its potential as a biomarker and/or therapeutic target.

A stepwise laboratory manual for the dissection and illustration of limbic and paralimbic structures: lessons learned from the Klingler's technique.

BACKGROUND: Three-dimensional relationships within the limbic and paralimbic areas are often hard to grasp. Relevant anatomical structures exhibit a complicated architecture and connectivity and therefore surgical approaches targeting lesions or functional resections in this area pose a distinct challenge. PURPOSE: To provide an educational, comprehensive, systematic and stepwise manual for the dissection and illustration of major limbic structures since there is a gap in the pertinent literature. Further, we aim to offer a thorough yet simplified roadmap for laboratory and intraoperative dissections. METHODS: Twenty (20) normal adult, formalin-fixed cerebral hemispheres were studied through the fiber dissection technique and under the microscope. Stepwise and in tandem medial to lateral and lateral to medial dissections were performed in all specimens aiming to reveal the morphology and spatial relationships of major limbic and paralimbic areas. RESULTS: Fourteen (14) consecutive, discrete and easily reproducible laboratory anatomical steps are systematically described to reveal the intricate anatomy of the limbic and paralimbic structures and their main connections. CONCLUSION: This study offers for the first time in the pertinent literature a focused, step-by-step laboratory manual for the dissection and illustration of the limbic and paralimbic structures. The overreaching goal is to supplement the novice and experienced anatomist and neurosurgeon with a thorough and systematic reference to facilitate laboratory or intraoperative dissections.

A computed tomography study on the olfactory fossa in dried skulls.

PURPOSE: The computed tomography (CT) study investigates the olfactory fossa (OF) morphometry and morphology. METHODS: Fifty Greek adult dried skulls were macroscopically investigated for the detection of the OF morphological patterns and after a multiplanar CT reconstruction, the OF morphometry was accurately calculated using a digital ruler. RESULTS: Types I and II surface contour patterns were the most frequently identified (36 and 32%), followed by types III, IV, and V (16, 12, and 4%). Crista galli mean length, height, and width were 19.46 ± 2.34 mm, 12.69 ± 2.7 mm, and 5.18 ± 1.11 mm. The OF mean maximum length was 22.29 ± 2.16 mm on the right and 22.10 ± 2.44 mm on the left side, and symmetry was detected. The OF median values of the maximum depth for its anterior, middle, and posterior third were 4.91 mm, 4.72 mm, and 2.78 mm on the right and 4.55 mm, 4.75 mm, and 2.55 mm on the left side. Symmetry was observed in any third of the OF. The OF median values of the surface maximum width for the anterior, middle, and posterior thirds were 9.29 mm, 11.48 mm, and 13.07 mm. A significant gradual increase of the OF surface maximum width was detected in the anteroposterior direction in the total sample (p < 0.001), with the highest value (23.12 mm) in the posterior third. A significant (p < 0.001) very strong (rs = -0.798) and a moderate (rs = -0.524) negative linear correlation in the OF anterior and middle third were, respectively, identified between its maximum depth and width. No gender impact was identified. CONCLUSIONS: The study helps to familiarize with the calculation of the OF dimensions and simplifies the understanding of its complex anatomy, to reach successful surgical planning and minimize perioperative complications.

Type 2 Diabetes Mellitus as a Risk Factor for Alzheimer's Disease: Review and Meta-Analysis.

Alzheimer's disease is the most common type of dementia, reaching 60-80% of case totals, and is one of the major global causes of the elderly population's decline in functionality concerning daily life activities. Epidemiological research has already indicated that, in addition to several others metabolic factors, diabetes mellitus type 2 is a risk factor of Alzheimer's disease. Many molecular pathways have been described, and at the same time, there are clues that suggest the connection between type 2 diabetes mellitus and Alzheimer's disease, through specific genes, autophagy, and even inflammatory pathways. A systematic review with meta-analysis was conducted, and its main goal was to reveal the multilevel connection between these diseases.

A distal anterior cerebral artery tripod branching to a bihemispheric pericallosal artery.

The anterior cerebral artery (ACA) branching pattern may be particularly complex and variant including bifurcations, trifurcations or quadrifurcations, thus leading to typical or atypical vessels. The bihemispheric ACA (BhACA) variant crosses the midline to supply the contralateral hemisphere. The current case highlights a left-sided ACA trifurcation into a bihemispheric pericallosal artery, and two ipsilateral atypical arteries: a callosomarginal artery of short course and a left-sided pericallosal artery of an aberrant course into the cingulate sulcus. The depicted trifurcation was characterized as a distal ACA tripod. The bihemispheric branch supplied the contralateral pericallosal area and coursed into the cingulate sulcus. Deviations from the typical ACA pattern, especially when they coexist are quite rare and may complicate neurosurgical approaches or raise diagnostic difficulties. The BhACA may be implicated in aneurysm formation and bilateral ischemia after its occlusion. Knowledge of such variants, as well as awareness of the complications they may be related to, is of great significance.