The supraorbital keyhole approach (SKA) is a minimally invasive corridor to the anterior skull base. However, inadvertent frontal sinus (FS) entry remains a primary complication. This study aims to quantify the relationship between surgical landmarks and FS morphometry to establish safety thresholds. Analysis was performed on 120 patients (53 males, 67 females; 48.5 ± 14.5 years old) using high-resolution computed tomography (CT) scans. Distances from the supraorbital notch (SON) and superior temporal line (STL) to the lateral FS border were measured. Statistical analysis was performed according to sides, sexes and FS pneumatization types. Receiver operating characteristic (ROC) curves and the 95% safety rule (5th percentile) were utilized to identify predictive morphometric thresholds and safe surgical corridors. Morphometric analysis recorded significant sexual dimorphism, with males exhibiting larger FS dimensions and more hyperplastic patterns (p < 0.001 and p = 0.013, respectively). Distances of surgical landmarks (SON, STL) from the FS lateral border were significantly different between the FS pneumatization patterns (p < 0.001). These distances were also statistically significant correlated with FS morphometric dimensions. The 95% safety rule established that the FS lateral border remains within 9.20 mm lateral to the SON, while a minimum safe window of 9.13 mm is maintained medial to the STL. ROC analysis identified FS width larger than 28.57 mm (AUC = 0.81) and height more than 23.93 mm (AUC = 0.77) as robust predictors of lateral sinus involvement. The proposed '9-mm safety algorithm' provides a standardized framework to minimize FS breach. Preoperative screening for ipsilateral FS width exceeding 28.57 mm serves as a critical diagnostic finding and highlights the need for patient-specific risk stratification for the supraorbital corridor.

BACKGROUND AND OBJECTIVES:This study highlights the significance of magnetic resonance (MR) venography in guiding surgical planning for the anterior interhemispheric transcallosal-transforaminal (AITT) approach to colloid cysts of the third ventricle. METHODS:We report a series of 32 patients who underwent the AITT approach for third ventricle colloid cysts. Demographic, clinical, neuroimaging, MR venography, surgical, and outcome data were collected prospectively and analyzed retrospectively. Preoperative planning relied particularly on time-of-flight MR venography to assess the patient's specific anatomy of the superficial and deep venous system. This tailored approach determined the site of the craniotomy in relation to the coronal suture and the access side to the ventricle based on the angle of the anterior septal and thalamostriate veins at the foramen of Monro. RESULTS:The colloid cyst was completely resected in all 32 patients without complications. The average patient age was 40 years, with headaches being the most frequent symptom (56.2%). MR venography played a pivotal role in identifying favorable superficial and deep venous patterns, leading to a tailored craniotomy, a good angle for the callosotomy (average: 83°), and selection of the ventricular side. An inverse correlation was found between the callosotomy angle and size, reducing the need for a larger callosal opening. All patients returned to their professional activities without neuropsychological deficits, and no recurrences were observed over an average follow-up of 112 ± 68 months. CONCLUSION:A comprehensive MR venography-guided AITT approach is essential for the craniotomy and selecting the ventricular access side, ensuring less traumatic and complete resection of colloid cysts while minimizing the risk of complications. This strategy consistently yielded good patient outcomes, no recurrences, and a rapid return to educational or professional activities.

Abstract Purpose Bipolar coagulation was historically described as a method for dome or neck remodeling, but concerns about rupture kept it underused. Yet carefully applied, low-power bipolar bursts can safely shrink or stiffen aneurysm walls, improving clip access in select challenging cases. This study aims to systematically evaluate how bipolar coagulation is used during intracranial aneurysm clipping, including its indications, intraoperative roles, and impact on surgical exposure and postoperative outcomes. Methods We retrospectively analyzed 50 consecutive patients who underwent microsurgical clipping of intracranial saccular aneurysms in which bipolar coagulation was deliberately employed. High-resolution surgical videos were reviewed to document the timing (pre-clip vs post-clip), target (dome vs neck), and purpose (remodeling, shrinkage, dissection assistance, or repair). Aneurysm morphology, rupture status, clip strategy, and perioperative variables were obtained from operative and radiological records. Patients were monitored clinically and radiographically at standardized intervals up to 24 months. Results Bipolar techniques were applied for neck remodeling in 31 patients (62%), dome coagulation in 30 patients (60%), post-clip coagulation in 29 patients (58%). Sole bipolar coagulation combined with cotton wrapping was used in 1 patient (2%). No statistically significant differences were observed among groups in preoperative WFNS scores (p = 0.20), discharge WFNS scores (mean 1.38 ± 1.07; p = 0.71), number of clips used (p = 0.56), mortality (p = 0.93), or indication distribution (p = 5.45). Early postoperative imaging demonstrated complete aneurysm obliteration in 48 of 50 patients (96%), while residual aneurysm was detected in 2 patients (4%). Overall mortality during follow-up was 6% (3/50), with no deaths attributable to surgical technique; all deaths were related to vasospasm. Conclusion Selective, low-power bipolar coagulation was used as an adjunct during aneurysm clipping without bipolar-related intraoperative rupture in this series. Its controlled use can enhance visualization, optimize clip positioning, and expand treatment options in anatomically challenging aneurysms.

The sphenoid sinus (SS) exhibits significant anatomical variability that critically impacts the safety and efficacy of endoscopic transsphenoidal surgery. This systematic review and meta-analysis aims to establish global prevalence rates for SS pneumatization patterns, extensions, and the relationship with adjacent neurovascular structures to guide surgical planning. A systematic literature search was conducted across PubMed, Google Scholar, Scopus, and Web of Science until October 2025. Studies reporting SS pneumatization types, extensions, and neurovascular protrusions/dehiscences based on imaging or cadaveric dissection were included. Random-effect models were used for the meta-analysis. The sellar type was the predominant pneumatization pattern, with the complete sellar type accounting for 48.39

INTRODUCTION:The mastoid emissary foramen (MEF), transmitting the mastoid emissary vein, is a key anatomical structure encountered during posterior cranial fossa and cerebellopontine angle approaches. Injury to this variable venous pathway may result in significant hemorrhage. However, published data regarding the prevalence and morphology of the MEF remain inconsistent. METHODS:A systematic review with meta-analysis was conducted according to PRISMA 2020 and Evidence-based Anatomy guidelines. Four databases were searched for osteological and imaging studies reporting MEF prevalence or morphometry were included. Pooled prevalence and morphometric estimates were calculated using random-effects models. RESULTS:Twenty-one studies comprising 8689 skull sides were included. The pooled prevalence of the MEF was 74% (95% CI: 65.16-82.03), with absence in 26%. A single MEF was most common (53%), while multiple MEFs were present in 16% of cases. Two, three, and four MEFs were observed in 12%, 4%, and 0.6% of cases, respectively. Nationality influenced the prevalence of multiple MEFs, whereas laterality and study type did not. The pooled mean diameter of the MEF was 2 mm (95% CI: 1.55-3.14). CONCLUSIONS:The MEF is a common but highly variable anatomical structure. Awareness of its prevalence and morphology is essential for neurosurgical planning, emphasizing the importance of high-resolution preoperative imaging to minimize vascular complications during posterior cranial fossa approaches.

The pretemporal anteromedial interdural approach provides direct extradural access to Meckel’s cave by exploiting the natural plane between the temporal dura propria and the meningeal layer of the lateral wall of the cavernous sinus. After a pretemporal craniotomy, the foramen rotundum guides interdural dissection along V2 toward the corridor between V1 and V2, enabling controlled exposure of the Gasserian ganglion and proximal trigeminal rootlets. Tumor resection proceeds through internal debulking and circumferential dissection, with extension into the posterior fossa when necessary. In this How I Do It article, we present the key technical steps of the pretemporal anteromedial interdural approach to Meckel’s cave, emphasizing anatomical landmarks and operative nuances. This approach allows safe and effective removal of trigeminal schwannomas while limiting cavernous sinus manipulation and reducing morbidity.

The World Federation of Neurosurgical Societies (WFNS) Young Neurosurgeons Committee conducted a global survey to identify key challenges affecting early-career neurosurgeons. These challenges ranging from restricted access to advanced training and limited research funding to insufficient mentorship, work-life imbalance, and experiences of gender and racial bias pose significant obstacles to professional growth and equitable neurosurgical development worldwide. A cross-sectional, web-based survey comprising 49 structured and open-ended questions was disseminated through neurosurgical networks, mailing lists, and social media. The target group included neurosurgeons within 10 years of completing residency. Data were analyzed using descriptive statistics for quantitative responses and thematic analysis for qualitative insights. Of the 500 respondents, 56.1

BACKGROUND AND OBJECTIVE:Endoscopic third ventriculostomy (ETV) is a minimally invasive procedure for hydrocephalus management. Variable neuroanatomical features in the floor of the third ventricle (3VF) and the basilar artery (BA) complex contribute to the risk of vascular lesions in the BA complex. This study aims to evaluate the neuroradiological characteristics of the 3VF with the BA complex to determine the ETV fenestration "vascular safe zone". METHODS:Preoperative neuroimaging studies from a consecutive cohort of adult patients who underwent ETV between January 2016 and March 2025 were retrospectively reviewed. Preoperative MRIs were used to evaluate the neuroradiological axial and sagittal characteristics of the 3VF with the BA complex. RESULTS:The neuroradiological BA complex position was described. In the sagittal plane, Type II (74 %) was the most common, with mean distances ranging from 4.1 mm to 8 mm. The mean distance from the top of the BA complex to the 3VF was 6.86 mm (SD 1.56 mm). In the axial plane, Classes C and D (71.2 %) were predominant and had varied distances to the 3VF. CONCLUSIONS:Our results suggest that the "vascular safe zone" for an ETV fenestration is primarily located in the anterior half of the 3VF. 71.2 % of our cases showed that the basilar artery (BA) complex was located in the posterior half. Future research should validate the "vascular safe zone" for ETV fenestration with neuroendoscopy intraoperative observations and assess clinical outcomes, including post-operative complications and success rates, to ensure the effectiveness of the proposed fenestration area.

Introduction:The jugular foramen (JF) is a critical anatomical structure that houses the lower cranial nerves (IX, X, and XI), making it a key focus in neurosurgical procedures. Variations, such as ossified dural septations within the JF, can significantly impact surgical outcomes. The present study investigates the incidence and impact of these ossifications on JF morphometry, providing insights crucial for surgical planning and execution. Materials and Methods:We analyzed bilaterally 120 adult dried skulls to assess the presence of accessory foramina (AF), proposing that these represent ossified dural septations. Morphometric measurements of the JF, including height and width, were taken in both cases with and without AF with the use of digital caliper. A thorough literature review was conducted to correlate the findings with clinical implications, and statistical analyses were used to determine significant morphological differences. Results:A complete AF was identified in 2.92% of skulls and an incomplete one in 0.42%. Ossified dural septations were associated with significantly reduced JF height and width. This reduction may hinder intraoperative manipulation, especially of the lower cranial nerves, increasing the potential for complications. Conclusion:The findings underscore the need to recognize JF variants, especially ossified septations, in neurosurgical practice. These variants can complicate surgical approaches to the skull base, highlighting the need for careful preoperative assessment. Future studies are warranted to explore the clinical ramifications of these findings, particularly to patient outcomes in skull base surgeries.

Surgeons frequently approach the foramen ovale (FO) via the infratemporal fossa (ITF) to treat trigeminal neuralgia. However, this percutaneous procedure could be unsuccessful due to anatomical factors. The present study aimed to assess the FO morphology and its relationship with the lateral pterygoid process plate (LPPP), emphasizing coexisting ITF variants. One-hundred-and-eight (216 sides) adult dried skulls were evaluated at the ITF (FO and LPPP). The FO maximum anteroposterior and lateromedial distances (APD and LMD) were calculated and correlated with the FO morphology. The FO-LPPP relationship was observed, and the presence of a sphenoidal emissary foramen (SEF) and possible ossified sphenoid bone’s ligaments variants (pterygoalar and pterygospinous—PTA and PTS variable ossification) were recorded. Statistical analysis was performed using the SPSS statistical program. The FO morphology was classified into three types after taking into consideration the FO morphometry. Type 1 FO was considered when the APD was two times more than the LMD (45.83%), Type 2 FO was identified when the APD was more than the LMD but no more than two times (51.85%), and Type 3 FO was considered when the APD and LMD were equal (2.32%). The FO and LPPP relationships were classified into the following four types: the direct type when the LPPP base ended at the FO center (32.3%), the lateral type was observed when the LPPP base ended at the FO lateral margin (28.76%), the far type was considered when the LPPP base ended distally to the FO (22.57%), and the medial type was when the LPPP base ended at the FO medial margin (11.95% of cases). Concerning the impact of the sphenoid bone variants on the FO-LPPP, the SEF did not alter the FO-LPPP relationship, while the PTA or PTS bar presence significantly affected it ( p < 0.001 and p = 0.007, respectively). When the sphenoid bone ossified bars were present, the most common type of FO was the medial one. A novel classification system was proposed for the FO morphology, assessing possible coexisting ITF variants that could alter the FO-LPPP relationship. Knowledge of these details would help clinicians perform percutaneous procedures to treat trigeminal neuralgia.

The vertical location of the basilar artery bifurcation (BAB) is a crucial factor in determining the best surgical approach for basilar tip (BAT) aneurysms. Although anatomical variants, such as the fetal-type posterior cerebral artery (FPCA), have been linked to aneurysm formation, their impact on BAB height remains unclear. A retrospective anatomical-imaging analysis of 250 high-resolution computed tomography angiograms (CTAs) was conducted to measure the vertical distance from the BAT to the clinoidal line (CL). A dominant posterior communicating artery and/or a hypoplastic or absent P1 segment defines the FPCA. BATs were classified into four types based on their BAT-CL distance, with Type 2 BATs (within ± 5 mm of the CL) being the most common. The mean BAT-CL distance was + 2.88 ± 4.8 mm. An FPCA was identified in 74 patients (29.6

With the rapid rise of artificial intelligence tools, applications like ChatPDF are seen as promising for supporting academic tasks in neurosurgery, such as literature review, summarization, and question generation. However, its accuracy and relevance remain to be critically assessed. This study assesses ChatPDF's accuracy in interpreting neurosurgical research articles, aiming to identify its strengths and limitations. Articles from the 10 highest-ranked neurosurgical journals were reviewed by selecting the first original research article from each journal's 2023 volume. Ten detailed questions were independently generated by 2 researchers based on each article's content. Each article was then uploaded to ChatPDF, which generated its own questions and provided responses to both its questions and those posed by the researchers. Responses were categorized as completely correct, partially correct, or incorrect. Source reliability was also evaluated to determine ChatPDF's performance. An overall accuracy rate of 89% was achieved by ChatPDF across 100 questions, with 89% of responses classified as completely correct, 5% as partially correct, and 6% as incorrect. Source reliability averaged 83%, although variability was noted, particularly in journals such as the Journal of Neurosurgery: Spine and Neurosurgery Clinics, which showed lower reliability rates. Substantial accuracy and potential were demonstrated by ChatPDF as a supplementary tool for neurosurgical literature review. However, limitations such as inconsistent source reliability and lack of visual content analysis highlight the need for ongoing refinement. While promising, ChatPDF should be used alongside manual verification to ensure comprehensive and accurate literature interpretation in neurosurgical research.

Background: The caroticoclinoid bar (CCB) or caroticoclinoid foramen (CCF) represents a well-described ossified variant of the skull base. It corresponds to an osseous bridge (resulting after homonymous ligament ossification) between the anterior and middle clinoid processes (ACPs and MCPs) surrounding the internal carotid artery (ICA)’s cavernous segment. Although extensive research has been performed on this clinically significant entity, only a few studies have been conducted on its effect on the ICA. The current study on dried skulls, using computed tomography (CT) and computed tomography angiography (CTA) scans, aimed to investigate the CCB’s presence and potential morphological stenosis patterns. Methods: One hundred (100) dried adult skulls and one hundred sixty (160) skulls from CT scans of patients were obtained (a total of 520 observations). To further calculate the ICA diameter (at the ACP-MCP region) and correlate the resulting dimeters with all potential morphological stenosis patterns of the CCB, thirty (30) CTAs of patients free of the variant were selected. Results: Concerning the osseous pattern morphology, of the total of 520 sides, the CCB was identified in 17.1%, the complete variant (creating a caroticoclinoid foramen-CCF) was calculated in 11.5%, and the incomplete one was calculated in 5.6%. No side, sex, or age impact was identified for the CCB presence. Concerning the ICA dimensions, its diameter was calculated to be between 4 and 5 mm. Thus, we observed three morphological stenosis patterns of the CCF. A low-risk pattern of stenosis (>5 mm diameter) was observed in 40 CCFs (44.9%), an intermediate risk of stenosis (4–5 mm diameter) in 38 CCFs (38.2%), and a high risk of stenosis (<4 mm diameter) was depicted in 15 CCFs (16.8%). Conclusions: In the present study, we investigated the CCF presence and potential morphological stenosis patterns by calculating and correlating the ICA diameter. In 16.8% of the current sample with CCFs (irrespective of their morphology), we observed that the ICA is probably at a high risk of compression. Radiologists and neurosurgeons intervening in the area should preoperatively diagnose the possibility of ICA compression in this area.

PurposeThis 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.MethodsThe 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.ResultsA 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.ConclusionThis 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.

BACKGROUND:Cirsoid aneurysms are rare arteriovenous fistulas involving direct connections between scalp arteries and draining veins, often located within the periosteal or temporal fascia, or beneath the galea. First described by Brecht in 1833, these lesions may be congenital or posttraumatic and can occasionally be associated with intracranial vascular malformations. OBSERVATIONS:A 69-year-old woman with thrombocytopenia developed a large cirsoid aneurysm in the right parieto-occipital subcutaneous region following head trauma. The lesion evolved into a soft tissue hematoma, eventually leading to a spontaneous cutaneous fistula with active, profuse bleeding. An endovascular embolization attempt failed due to complex vascular architecture. Emergency surgical intervention was performed for hematoma evacuation and complete resection of the vascular malformation. LESSONS:This case is unique in combining several high-risk factors rarely reported together: an acutely ruptured cirsoid aneurysm, severe thrombocytopenia, and failed endovascular embolization due to prohibitive vessel tortuosity. A successful outcome was achieved through rapid multidisciplinary coordination-integrating neurosurgical expertise for definitive nidus excision, hematological optimization, and reconstructive planning to preserve scalp integrity. https://thejns.org/doi/10.3171/CASE25508.

Brainstem cavernous malformations are relatively rare lesions with a higher tendency of hemorrhage than supratentorial cavernous malformations. Due to the compact arrangement of fiber tracts and nuclei of the region, any hemorrhagic event can cause severe neurological deficits. This eloquent architecture of the area also makes any surgical attempt challenging. Anatomical location and dimension of the lesion, presence of hemorrhage, age, and the neurological status of the patient need to be considered before determining the appropriate course of treatment. A surgical approach is preferred for young symptomatic patients with at least 1 previous episode of bleeding. Subtemporal and supracerebellar infratentorial approaches can be used to access these lesions.1-5 We present a 44-year-old woman with a hemorrhagic tegmental cavernous malformation presenting with imbalance and right-sided hemiparesis (Video 1). The paramedian supracerebellar infratentorial translateral mesencephalic sulcus approach is used to resect the lesion with the patient in a dynamic lateral semisitting position. The paramedian variant of the supracerebellar infratentorial approach provides a relatively bridging vein-free corridor compared with midline approaches.6 With the patient in the semisitting position, gravity retraction of the brain provided a natural corridor with a clear surgical field. In the dynamic lateral semisitting position, we aimed to reduce the risk of venous air embolism associated with the sitting position by keeping the patient in the lateral decubitus position during the dural and extradural phases of the surgery.7

BACKGROUND AND OBJECTIVES:Occipital condylar canals (OCCs) and associated condylar emissary veins contribute to brain thermoregulation, waste clearance, and venous outflow, particularly in an upright posture, supporting intracranial pressure regulation and cerebral homeostasis. When present, OCCs are critical landmarks in posterolateral skull base approaches, including the far lateral and transcondylar surgical routes. Their identification is useful for avoiding neurovascular injury during craniovertebral junction procedures. Despite their potential surgical relevance, the variability in OCCs (presence, associated symmetry or asymmetry, and morphometry) remains poorly documented. This study aimed to provide a detailed identification analysis of the inconsistent OCCs [the posterior condylar canals (PCCs) and paracondylar canals (PCs)], emphasizing their morphometry to enhance applied anatomic knowledge and improve surgical planning. METHODS:A total of 113 dried adult European skulls were examined at the National and Kapodistrian University of Athens to determine the prevalence of PCCs and PCs. When present, morphometric evaluations were performed according to laterality using metal wire probes to confirm patency. The prevalence of presence and absence was recorded based on laterality. All variables were additionally analyzed by sex, and significance was assessed using Fisher's exact test (P < .05). RESULTS:PCC was identified in 74.3% of the specimens (bilateral, 44.2%; unilateral left-sided, 13.3%; and unilateral right-sided, 16.8%). Females showed a higher prevalence of PCC (80%) than males (58.6%). PC was observed in 9.7% of specimens. In the authors' experience, when present, the PCC and the corresponding condylar emissary veins served as useful anatomic landmarks during the far-lateral approach. CONCLUSIONS:This study highlights the anatomic variability and surgical relevance of the PCC, PC, and their emissary veins. Though not consistently reliable landmarks, their identification and variation assessment may aid preoperative planning and intraoperative safety by reducing bleeding risk and preserving craniovertebral junction stability.

Glioblastoma (GBM) is the most common malignant central nervous system tumor. The emerging field of epigenetics stands out as particularly promising. Notably, the discovery of micro RNAs (miRNAs) has paved the way for advancements in diagnosing, treating, and prognosticating patients with brain tumors. We aim to provide an overview of the emergence of miRNAs in GBM and their potential role in the multifaceted management of this disease. We discuss the current state of the art regarding miRNAs and GBM. We performed a narrative review using the MEDLINE/PUBMED database to retrieve peer-reviewed articles related to the use of miRNA approaches for the treatment of GBMs. MiRNAs are intrinsic non-coding RNA molecules that regulate gene expression mainly through post-transcriptional mechanisms. The deregulation of some of these molecules is related to the pathogenesis of GBM. The inclusion of molecular characterization for the diagnosis of brain tumors and the advent of less-invasive diagnostic methods such as liquid biopsies, highlights the potential of these molecules as biomarkers for guiding the management of brain tumors such as GBM. Importantly, there is a need for more studies to better examine the application of these novel molecules. The constantly changing characterization and approach to the diagnosis and management of brain tumors broaden the possibilities for the molecular inclusion of novel epigenetic molecules, such as miRNAs, for a better understanding of this disease.