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Background: Endoscopic endonasal surgical resection is an effective therapeutic approach for olfactory neuroblastoma (ONB). Unilateral excision of ONBs with limited extension has been reported with the purpose of preserving olfactory function. We aimed to review implications of surgical management, olfactory preservation feasibility, and survival outcomes in patients who underwent endoscopic unilateral resection of ONB., Methods: A systematic literature review was conducted using the search terms [("Olfactory neuroblastoma") OR ("Esthesioneuroblastoma")] AND [("Unilateral resection") OR ("Olfaction preservation")]. Studies reporting cases of unilateral ONB endoscopic resection with postoperative olfaction assessment were included. Concurrently, records of patients who met inclusion criteria at our institution were reviewed retrospectively. The survival and olfactory outcomes were analyzed in both cohorts., Results: Thirty-three patients were identified in the published literature. Twenty-three (69.7%) reported postoperative olfaction preservation. Olfactory function after surgery did not show an association with Kadish stage (P = 0.128). No evidence of disease was observed at the latest follow-up in this group of patients. Nine patients who met inclusion criteria were identified at our institution. The extent of resection influenced the level of olfaction preservation when cribriform plate and nasal septum resection coexisted (P = 0.05). A single patient at our institution developed recurrence after being lost to follow-up for 22 months., Conclusions: Olfaction preservation can be achieved in patients who undergo endoscopic unilateral resection and adjuvant radiotherapy. The extent of resection should aim for negative margins, particularly in the midline. Larger studies are required to assess the risk of contralateral microscopic disease, and, hence, close follow-up is advised., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Implementation of standardized protocols in neurooncology during the surgical resection of brain tumors is needed to advance the clinical treatment paradigms that use tissue for diagnosis, prognosis, bio-banking, and treatment. Currently recommendations on intraoperative tissue procurement only exist for diffuse gliomas but management of other brain tumor subtypes can also benefit from these protocols. Fresh tissue from surgical resection can now be used for intraoperative diagnostics and functional precision medicine assays. A multidisciplinary neuro-oncology perspective is critical to develop the best avenues for practical standardization. This perspective from the multidisciplinary Oncology Tissue Advisory Board (OTAB) discusses current advances, future directions, and the imperative of adopting standardized protocols for diverse brain tumor entities. There is a growing need for consistent operating room practices to enhance patient care, streamline research efforts, and optimize outcomes., Competing Interests: The authors, except WJS, are members of an advisory board sponsored by Nico Corporation. However, Nico Corporation was not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication. CB is a consultant for Depuy-Synthes, Bionaut Labs, Haystack Oncology and Privo Technologies. CB is a co-founder of OrisDx and Belay Diagnostics. HB is a chairman of the Medical Advisory Board for Insightec. Insightec is developing focused ultrasound treatments for brain tumors. This arrangement has been reviewed and approved by the Johns Hopkins University in accordance with its conflict-of-interest policies. HB has consultation agreements with Insightec, Candel Therapeutics, Inc., Catalio Nexus Fund II, LLC, LikeMinds, Inc*, and Nurami Medical*, Intragel *includes equity or options. The remaining author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Rodriguez, Ahluwalia, Bettegowda, Brem, Carter, Chang, Das, Eberhart, Garzon-Muvdi, Hadjipanayis, Hawkins, Jacques, Khalessi, McDermott, Mikkelsen, Orr, Phillips, Rosenblum, Shelton, Solomon, von Deimling, Woodworth and Rutka.)

Objective: Brain tumors display remarkable cellular and molecular diversity, significantly impacting the progression and outcomes of the disease. The utilization of tumor tissue acquired through surgical handheld devices for tumor characterization raises important questions regarding translational research. This study seeks to evaluate the integrity of tissue resected using a microdebrider (MD) in the context of establishing tumor organoids from glioblastomas (GBM)., Methods: Tumor samples were collected from patients with GBM using both tumor forceps (en bloc) and a MD. The time required to protocol completion and cell viability of paired samples was measured. H&E staining was performed to examine histologic morphology., Results: Ten paired samples were obtained from GBM patients using tumor forceps and the MD. Samples collected with the MD demonstrated significantly shorter processing times compared to those obtained through en bloc resection, with overall means of 31.7 ± 2.4 mins and 38.8±3 mins, respectively (P < 0.001). Cell viability measured at the end of protocol completion was comparable between tissues obtained using both the MD and en bloc, with mean viabilities of 80.2 ± 12.4% and 79.1 ± 12.5%, respectively (P = 0.848). H&E examination of tissues revealed no significant differences in the cellular and histologic characteristics of paired samples obtained using both methods across GBM tumors, nor in the corresponding established organoids., Conclusions: Tumor tissues obtained using the MD and en bloc methods demonstrate a high success rate in establishing GBM organoids, with the MD offering the advantage of significantly reduced processing time. Both methods display comparable cell viability and maintain consistent histologic characteristics in the resected tissue and the corresponding organoids., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background and Objectives: Traditional and well-established transcranial approaches to the spheno-orbital region and middle cranial fossa guarantee optimal intracranial exposure, and additional orbital and zygomatic osteotomies provide further control over extracranial components to be resected; however, these techniques come at the cost of additional morbidity. The introduction of minimally invasive endoscopic approaches and the conceptualization of the so-called "multiportal" paradigm might provide an alternative route. This preliminary study investigates the feasibility of the combined Biportal Endoscopic TransOrbital and transMaxillary Approach (bETOMA) approach to the spheno-orbital and middle cranial fossa regions., Methods: Using 4 silicon-injected adult cadaver heads (8 sides; 16 approaches), we systematically dissected through superior eyelid ETOA and endoscopic TMA approaches. The analysis focused on pterygopalatine, infratemporal, anterior and middle cranial fossae, Meckel cave, and cavernous sinus access. We evaluated the feasibility of bETOMA using linear distances, angles of attack, and exposure areas. We also introduced volume of operative maneuverability, its standardized derivative (sVOM), target distance, visuo-operative angle, and working zone volume as novel metrics., Results: The analysis revealed comparable angles of attack between approaches. ETOA and TMA exposure areas were 918.38 ± 223.93 mm2 and 257.07 ± 86.07 mm2, respectively. TMA showed a larger VOM in the greater sphenoid wing, but ETOA offered superior distal maneuverability (sVOM: 5.39 ± 1.94 vs 2.54 ± 0.79 cm3) and closer intracranial space access (27.45 vs 50.83 mm). The combined approaches yielded a mean working zone volume of 13.75 ± 3.73 cm3 in the spheno-orbital interface., Conclusion: The bETOMA approach provides adequate neurovascular exposure and maneuverability to the spheno-orbital region, infratemporal, and anterior and middle cranial fossae, addressing significant limitations of previously investigated monoportal techniques (ie, optic nerve decompression, hyperostotic bone resection, and infratemporal exposure). This combined minimally invasive approach might help manage lesions harbored within the cranio-orbital interface region invading the extracranial space., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Background and Objectives: The emergence of machine learning models has significantly improved the accuracy of surgical outcome predictions. This study aims to develop and validate an artificial neural network (ANN) model for predicting facial nerve (FN) outcomes after vestibular schwannoma (VS) surgery using the proximal-to-distal amplitude ratio (P/D) along with clinical variables., Methods: This retrospective study included 71 patients who underwent VS resection between 2018 and 2022. At the end of surgery, the FN was stimulated at the brainstem (proximal) and internal acoustic meatus (distal) and the P/D was calculated. Postoperative FN function was assessed using the House-Brackmann grading system at discharge (short-term) and after 9-12 months (long-term). House-Brackmann grades I-II were considered good outcome, whereas grades III-VI were considered fair/poor. An ANN model was constructed, and the performance of the model was evaluated using the area under the ROC curve for internal validation and accuracy, sensitivity, specificity, and positive and negative predictive values for external validation., Results: The short-term FN outcome was grades I-II in 57.7% and grades III-VI in 42.3% of patients. Initially, a model using P/D had an area under the curve of 0.906 (internal validation) and an accuracy of 89.1% (95% CI: 68.3%-98.8%) (external validation) for predicting good vs fair/poor short-term FN outcomes. The model was then refined to include only muscles with a P/D with a proximal latency between 6 and 8 ms. This improved the accuracy to 100% (95% CI: 79%-100%). Integrating clinical variables (patient's age, tumor size, and preoperative HB grade) in addition to P/D into the model did not significantly improve the predative value. A model was then created to predict the long-term FN outcome using P/D with latencies between 6 and 8 ms and had an accuracy of 90.9% (95% CI: 58.7%-99.8%)., Conclusion: ANN models incorporating P/D can be a valuable tool for predicting FN outcomes after VS surgery. Refining the model to include P/D with latencies between 6 and 8 ms further improves the model's prediction. A user-friendly interface is provided to facilitate the implementation of this model., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

Background and Objectives: Spheno-orbital meningiomas arise from the arachnoid villi cap cells at the sphenoid ridge and have the ability to spread through soft tissue extension and cranial bone invasion. Owing to their orbital hyperostosis and intraorbital soft tissue extension, they commonly present with ophthalmologic manifestations. This study aims to investigate the correlation between tumor volume with the presenting symptoms and postoperative outcomes., Methods: This retrospective study analyzed patients who underwent surgical resection of spheno-orbital meningiomas. Tumor volumes in different compartments were measured using preoperative and postoperative imaging. Linear and logistic regression analyses were used to identify correlations between tumor volumes and presenting symptoms preoperatively and postoperative outcomes., Results: Sixty-six patients were included in this study, of whom 86.4% had proptosis, 80.3% had decreased visual acuity (VA), 30.3% had visual field defects, and 13.6% had periorbital edema. Preoperatively, proptosis linearly correlated with intraosseous tumor volume (coefficient = 0.6, P < .001), while the decrease in baseline VA correlated with the intraorbital tumor volume (coefficient = 0.3, P = .01). The odds of periorbital edema were found to increase with an increase in intraosseous tumor volume with an adjusted odds ratio of 1.4 (95% CI, 1.1-1.7, P = .003), while the odds of visual field defects were found to increase with an increase in intraorbital tumor volume with an adjusted odds ratio of 2.7 (95% CI, 1.3-5.6, P = .01). Postoperatively, the volume of intraosseous tumor resected linearly correlated with the improvement in proptosis (coefficient = 0.7, P < .001), while the volume of intraorbital tumor resected linearly correlated with improvement in VA (coefficient = 0.5, P < .001) and with a larger effect size in patients presenting with moderate-to-severe decrease in VA preoperatively (coefficient = 0.8)., Conclusion: Underscoring the importance of each tumor compartment relative to the patient's symptomatology serves as a valuable guide in implementing a compartmentalized resection approach tailored to the surgical objectives., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

Introduction: Spheno-orbital meningiomas (SOMs) represent a distinct subtype of meningioma characterized by their unique multi-compartmental invasion pattern. Previous studies have investigated correlations between SOMs and visual manifestations. However, our comprehension of pain associated with SOMs remains limited. This study aims to provide insight into the pathophysiology underlying SOM-related pain through measurements of tumor volume and superior orbital fissure (SOF) narrowing., Methods: This retrospective study included patients who underwent surgical resection of a SOM between 2000 and 2022. Preoperative CT and/or MRI scans were analyzed, and the tumor volume of each segment was measured. Bony 3D reconstructions were used to measure the area of the SOF, and SOF narrowing was calculated., Results: The study cohort included 66 patients diagnosed with SOMs, among which 25.8% (n = 17) presented with pain. Postoperatively, 14/17 (82.4%) of patients reported pain improvement. There was no significant correlation between the total volume or the volume of tumor within each compartment and the presence of pain on presentation (p > 0.05). The median SOF narrowing was significantly different between patients presenting with and without tumor-associated pain with median of 11 mm 2 (IQR 2.8-22.3) and 2 mm 2 (IQR 0-6), respectively (p = 0.005). Using logistic regression, a significant correlation between the degree of SOF narrowing and the presence of SOM-associated pain on presentation was identified, with an aOR of 1.2 (95% CI 1.12-1.3, p = 0.02)., Conclusion: While the exact cause of tumor-associated pain remains unclear, SOF narrowing seems to play a role in pain among SOM patients. Based on the radiological characteristics, SOF neurovascular decompression is recommended in SOM patients., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

The angle of exposure (AnE) represents a metric that is particularly useful for analyzing circular bony structures during skull base dissections. The authors aimed to develop and validate a neuronavigation-based method to measure the AnE. A formula based on vectorial geometry and the coordinates of three points collected with a neuronavigation system was developed to measure the AnE. The method was validated using a plexiglass phantom head. To demonstrate its applicability, the authors measured the AnE in 6 cadaveric specimens after exposure of the hypoglossal canal using a far-medial approach (FMA) and a far-lateral transtubercular approach (FLTA) and in 6 different specimens after exposure of the jugular foramen using an FLTA and a retrosigmoid approach (RSA). The mean angles measured at 45°, 90°, and 180° using a goniometer during the validation test were 44.8° ± 1.1°, 90.8° ± 1.2°, and 179.7° ± 0.8° using the novel formula (p > 0.05). In the first illustrative application, the mean AnEs for the FMA and FLTA were 129° ± 0.9° and 243° ± 1.9°, respectively. In the second scenario, the mean AnEs were 192° ± 1.3° for the FTLA and 143° ± 2.1° for the RSA. The neuronavigation-based technique described is a highly accurate method to measure the AnE.

Background: Cavernous malformations (CMs) are clusters of thin-walled sinusoidal vessels without well-defined walls. Though they can occur anywhere in the neuroaxis, cranial nerve (CN) CMs are rare., Method: We report a 47-year-old male with gradual CN III palsy. Initial imaging showed no significant findings, but a follow-up MRI revealed a growing lesion along CN III. Intraoperative findings confirmed a CN III CM. Diagnosing and treating CN III CM are complex. Radiological findings lack specificity, requiring consideration of various diagnoses for patients with isolated CN III palsy and abnormal radiological findings., Conclusion: Surgery is the gold standard, aiming for complete lesion removal while minimizing neurological complications., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Background: Infectious intracranial aneurysms (IIAs) are a rare sequel of systemic infection and occur most commonly in patients with infective endocarditis (IE). Despite the increasing use of non-invasive screening angiography in patients with IE, the incidence remains low, yielding limited data on the management of IIAs in pediatric populations. We performed a pooled analysis of all published series of pediatric patients with IIAs to study the disease landscape including presentation, management, and outcomes., Methods: Data included in this study were pooled from published literature on IIAs between 1960 and 2023. Abstracts were selected for full review to include only manuscripts reporting at least one case of pediatric IIA (age 0-18 years)., Results: A total of 145 pediatric patients with 178 IIAs were included. Patients presented with rupture in 68% of cases, of which 36% had intraparenchymal hemorrhage and 39% had subarachnoid hemorrhage. Using multivariate logistic regression, independent predictors of rupture were posterior location (aOR 10, P=0.041) and history of IE (aOR 7.2, P=0.001). Primary medical management was successful in 82% of cases with unruptured aneurysms while, in those with ruptured IIAs, medical management was successful in 26% of cases. The 90-day mortality rate was 28%. Using multivariate logistic regression, ruptured IIAs (aOR 5.4, P<0.01) and failure of medical management (aOR 11.1, P<0.05) were independent predictors of 90-day mortality., Conclusion: Pediatric IIAs remain a rare complication of systemic or localized CNS infection in the pediatric population. Medical management of unruptured aneurysms is highly successful, while ruptured aneurysms have a remarkably high rate of failure of medical management and should be treated by early surgical or endovascular intervention when feasible., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Brain tumors display significant inter and intratumoral heterogeneity, impacting disease progression and outcomes. Preserving surgically resected tissue is vital for ensuring accurate research results to enhance understanding of tumor pathophysiology. This study evaluates tissue integrity and viability of tissue resected using 2 surgical devices for tumor resection: a mechanical microdebrider (MD) and an ultrasonic aspirator (UA)., Methods: Tumor samples were obtained from patients undergoing surgical resection of primary and secondary intracranial tumors. Cell viability was assessed, and histopathological analysis of Hematoxylin and Eosin -stained tissues was performed. Adherent monolayer and neurospheres cell cultures were established from paired samples. RNA isolation and quantitative polymerase chain reaction of housekeeping genes were conducted to compare genetic integrity., Results: The cellular viability was comparable between samples obtained using both the MD and the UA, with a mean viability of 75.2% ± 15.6 and 70.7% ± 16.8, respectively (P = 0.318). Histopathological evaluation indicated no discernible differences in cellular integrity between the devices. Cell culture success rates and growth characteristics were similar for both devices. RNA concentration and integrity were well-maintained in both MD and UA samples, with no significant differences (P = 0.855). Quantitative polymerase chain reaction analysis of housekeeping genes showed consistent results across matched tissues from both devices and different tumor pathologies., Conclusions: Surgical handheld devices provide valuable, high-quality tissue samples for research. Surgeon preference, tumor pathology, and anatomical location dictate device choice. Both MD and UA devices are reliable for obtaining quality tissue specimens, facilitating translational neuro-oncology research., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Atypical teratoid/rhabdoid tumor (ATRT) is a rare, highly aggressive central nervous system tumor predominantly found in children. Limited information exists on ATRT in adults, posing challenges in diagnosis and treatment. This study presents the case of an adult patient with ATRT in the sellar region and explores the impact of different treatment regimens on patient survival., Observations: A 60-year-old female with an ATRT underwent resection of the tumor, followed by adjuvant chemoradiotherapy. Molecular genetic analysis revealed compound heterozygous SMARCB1 point mutations. Survival analysis was performed on previously published adult ATRT cases, comparing treatment approaches. The cohort's overall median survival was 6 months, with patients receiving combined chemoradiotherapy showing the longest median survival of 23.5 months. Statistical analysis demonstrated a significant difference in survival between patients treated with surgery alone and those receiving surgery followed by chemoradiotherapy (p < 0.001). However, no significant difference was observed between patients treated with surgery alone and those with postoperative radiotherapy (p = 0.105)., Lessons: Early initiation of adjuvant chemoradiotherapy following surgery improves survival outcomes in adult patients with ATRT. Because of limited data on standardized treatment protocols for adults with ATRT, further research and larger-scale studies are needed to establish effective treatment guidelines for this population.

Background: The ultrasonic aspirator micro claw tool (UAmCT) can be used to remove the bone of the internal auditory canal (IAC) during vestibular schwannoma resection via the retrosigmoid approach (RSA) without the risk of a spinning drill shaft. However, the thermal profile of the UAmCT during IAC removal has not been reported., Objective: To compare the thermal profile of the UAmCT during access of the IAC to that of a conventional high-speed drill (HSD) and to present an illustrative case of this application., Methods: IAC opening via RSA was performed in 5 embalmed cadaveric specimens using the UAmCT with 3, 8, and 15 mL/min irrigation on the left and the HSD at 75 000 revolutions per minute and 0%, 14%, and 22% irrigation on the right. Peak bone surface temperatures were measured 4 times in 20-second intervals, and statistical analyses were performed using SPSS software. An illustrative case of a vestibular schwannoma resected via an RSA using the UAmCT to access the IAC is presented., Results: The IAC was opened in all 5 specimens using both the UAmCT and HSD without complication. The mean peak bone surface temperatures were significantly lower with the UAmCT compared with the HSD ( P < .001). The UAmCT did not meaningfully prolong the operating time in the illustrative case, and the IAC was accessed without complication., Conclusion: The UAmCT may be a safe and effective alternative to HSD for IAC opening during vestibular schwannoma resection via the RSA. Larger studies under clinical conditions are required to further validate these findings., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

Introduction: Aggressive prolactinomas (APRLs) pose a significant clinical challenge due to their high rate of regrowth and potentially life-threatening complications. In this study, we present a case of a patient with an APRL who had a trial of multiple therapeutic modalities with the aim to provide a review of molecular abnormalities and management of APRLs by corroborating our experience with previous literature., Methods: A total of 268 articles were reviewed and 46 were included. Case reports and series, and studies that investigated the molecular and/or genetic analysis of APRLs were included. Special care was taken to include studies describing prolactinomas that would fall under the APRL subtype according to the European Society of Endocrinology guidelines; however, the author did not label the tumor as "aggressive" or "atypical". Addiontionally, we present a case report of a 56-year-old man presented with an invasive APRL that was resistant to multiple treatment modalities., Results: Literature review revealed multiple molecular abnormalities of APRLs including mutations in and/or deregulation of ADAMTS6, MMP-9, PITX1, VEGF, POU6F2, CDKN2A, and Rb genes. Mismatch repair genes, downregulation of microRNAs, and hypermethylation of specific genes including RASSF1A, p27, and MGMT were found to be directly associated with the aggressiveness of prolactinomas. APRL receptor analysis showed that low levels of estrogen receptor (ER) and an increase in somatostatin receptors (SSTR5) and epidermal growth factor receptors (EGFR) were associated with increased invasiveness and higher proliferation activity. Our patient had positive immunohistochemistry staining for PD-L1, MSH2, and MSH6, while microarray analysis revealed mutations in the CDKN2A and POU6F2 genes. Despite undergoing two surgical resections, radiotherapy, and taking dopamine agonists, the tumor continued to progress. The patient was administered pazopanib, which resulted in a positive response and the patient remained progression-free for six months. However, subsequent observations revealed tumor progression. The patient was started on PD-L1 inhibitor pembrolizumab, yet the tumor continued to progress., Conclusion: APRLs are complex tumors that require a multidisciplinary management approach. Knowledge of the molecular underpinnings of these tumors is critical for understanding their pathogenesis and identifying potential targets for precision medical therapy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Medina, Zohdy, Porto, Revuelta Barbero, Bray, Maldonado, Rodas, Mayol, Morales, Neill, Read, Pradilla, Ioachimescu and Garzon-Muvdi.)

Introduction  This study highlights the relation between compound muscle action potential (CMAP) latency variations and the predictive value of facial nerve (FN) proximal-to-distal (P/D) amplitude ratio measured at the end of vestibular schwannoma resection. Methods  Forty-eight patients underwent FN stimulation at the brainstem (proximal) and internal acoustic meatus (distal) using a current intensity of 2 mA. The proximal latency and the P/D amplitude ratio were assessed. House-Brackmann grades I & II indicated good FN function, and grades III to VI were considered fair/poor function. A P/D amplitude ratio > 0.6 was used as a cutoff to indicate a good FN function, while a ratio of ≤ 0.6 indicated a fair/poor FN function. Results  The P/D amplitude ratio was measured for all patients, and the calculated sensitivity (SE), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV) were 85.2, 85.7, 88.5, and 81.8%, respectively. The CMAPs from the mentalis muscle were then classified based on their proximal latency into group I (< 6 ms), group II (6-8 ms), and group III (> 8 ms). The SE, SP, PPV, and NPV became 90.5, 90.9, 95, and 83.3%, respectively, in group II. In group I, SE and NPV increased, whereas SP and PPV decreased. While in group III, SP and PPV increased, whereas SE and NPV decreased. Conclusion  At a latency between 6 and 8 ms, the P/D amplitude ratio was predictive of outcomes with high SE and SP. When latency was < 6 ms or > 8 ms, the same predictive ability was not observed. Knowing the strengths and limitations is important for understanding the predictive value of the P/D amplitude ratio., Competing Interests: Conflict of Interest None declared., (Thieme. All rights reserved.)

Background: Intracranial tumors are infrequently encountered during pregnancy, and their diagnosis and management require a multidisciplinary approach to ensure the best possible outcomes for the mother and fetus. The pathophysiology and manifestations of these tumors are influenced by hormonal changes, hemodynamic modifications, and alterations in immunological tolerance that occur during pregnancy. Despite the complexity of this condition, no standardized guidelines exist. This study aims to highlight the key points of this presentation, along with the discussion of a possible management algorithm., Observations: The authors report the case of a 35-year-old woman who presented during the third trimester of pregnancy with severe signs of increased intracranial pressure (ICP) due to a posterior cranial fossa mass. The decision was made to stabilize the patient by placing an external ventricular drain to temporize her increased ICPs until the baby could be safely delivered via cesarean section. The mass was resected via suboccipital craniectomy 1 week postpartum., Lessons: In considering treatment modalities and their timing in patients presenting with intracranial tumors during pregnancy, each patient should be managed on the basis of an individual treatment algorithm. Symptoms, prognosis, and gestational age should be taken into account to optimize the surgical and perioperative outcomes of both the mother and fetus.

Background: The radial forearm free flap (RFFF) is an indispensable tool for the reconstruction of a range of defects, including those of the skull base. Several options for routing of the RFFF pedicle have been described, and the parapharyngeal corridor (PC) has been proposed as an option and employed for a nasopharyngeal defect. However, there are no reports of its use for the reconstruction of anterior skull base defects. The objective of this study is to describe the technique for free tissue reconstruction of anterior skull base defects using the RFFF and routing of the pedicle via the PC., Methods: Relevant neurovascular landmarks and critical surgical steps for reconstruction of anterior skull base defects with an RFFF and routing of the pedicle via the PC are reported using an illustrative clinical case and cadaveric dissections., Results: We present a case of a 70-year-old man who underwent endoscopic transcribriform resection of cT4N0 sinonasal squamous cell carcinoma and was left with a large anterior skull base defect that persisted despite several repair attempts. An RFFF was utilized to repair the defect. This report is the first description of the clinical use of the PC for free tissue repair of an anterior skull base defect., Conclusions: The PC is an option for routing the pedicle during the reconstruction of anterior skull base defects. When the corridor is prepared as described in this case, a direct route exists from the anterior skull base to cervical vessels, simultaneously maximizing the reach of the pedicle and minimizing the risk of kinking., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Competing Interests: None declared.

Background: Internal carotid artery injury (ICAI) represents one of the most challenging complications in endoscopic endonasal neurosurgery and its rarity results in limited opportunities for trainees and surgeons to achieve proficiency in its management. Currently, available models for ICAI have employed costly systems that prevent their widespread use. The objective of this study is to validate an affordable submersible peristaltic pump (SPP)-based model as a reproducible and realistic paradigm for ICAI management training., Methods: A laceration of the left parasellar internal carotid artery was purposely carried out in 2 human cadaveric heads. A blood substitute was perfused to ensure a perfusion flow of 1 L/min using an affordable SPP. A cohort of 20 neurosurgery and otolaryngology residents, fellows, and attendings were enrolled to evaluate the realism and content validity of the model using a validated 5-grade questionnaire., Results: The model proved to mimic a real intraoperative scenario of ICAI with an expected output flow of 1 L/min. Questionnaire responses reported a realistic experience and the impact of this model on improving trainee surgical coordination and capability to rehearse the most accepted repair technique. The use of a fixed noninjected head allowed the reproducibility of the training session without the additional cost of new fresh-frozen heads. The affordable SPP allowed an impactful reduction of ICAI model training expenses maintaining high realism., Conclusions: The SPP-based ICAI model with noninjected cadaveric specimens is an affordable and cost-effective system that allows reproducibility and realism. These qualities favor greater adoption in neurosurgery and otolaryngology training curricula., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Different materials and techniques have been proposed for surgical repair of spontaneous middle cranial fossa (MCF) defects. However, conclusive evidence supporting their selection and impact on clinical outcomes is lacking. The study aims to conduct a systematic review and meta-analysis on materials and techniques employed to repair MCF defects and evaluate complications and rates of recurrent cerebrospinal fluid (CSF) leaks. A PRISMA-guided systematic review and meta-analysis were performed using MESH terms and specific keywords including studies published before May 2022. Primary outcomes included recurrence of CSF leak and complication rates by type of reconstructive material and technique utilized. Meta-analyses of proportions were performed using random effects and confidence intervals for individual proportions were calculated using the Clopper-Pearson method. Twenty-nine studies were included (n = 471 cases). Materials employed for repair were categorized according to defect size: 65% of defects were of unknown size, 24% were small (< 1 cm), and 11% were large (≥ 1 cm). Rigid reconstruction (RR) was significantly favored over soft reconstruction (SR) for larger defects (94% of cases, p < 0.05). Complications and recurrent CSF leak rates of SR and RR techniques were comparable for defects of all sizes (p > 0.05). Complication rates reported for these procedures are low regardless of technique and material. RR was universally preferred for larger defects and analysis of complication and recurrence rates did not reveal differences regardless of defect size. While RR was more frequently reported in smaller defects, SR was used by several centers, particularly for smaller MCF floor defects., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Recent studies highlighted how exoscopes may be employed to approach the lateral skull base. The use of exoscope-assisted procedures to repair middle cranial fossa (MCF) defects has not been fully explored. The surgical microscope in the same circumstances has been associated with relevant limitations, such as its physical obstruction, among others. The aim of this study was to present a proof of concept of exoscope-assisted surgery for MCF defects., Methods: A detailed step-by-step MCF approach was performed on 2 alcohol-preserved, latex-injected cadaveric specimens under exoscopic magnification. An illustrative clinical case of encephalocele secondary to a spontaneous tegmen tympani defect repaired via an exoscope-assisted MCF approach was presented., Results: The most common sites of MCF defects, the tegmen tympani and the arcuate eminence, were successfully exposed under exoscopic magnification. Dissection was easily performed; no damage to the dura mater or to vascular or neural structures occurred. In the clinical case, the exoscope-assisted technique demonstrated adequate maneuverability and magnification quality. After localization, the encephalocele was resected, and the MCF defect was repaired. The surgeon's position was comfortable, and operative time was not prolonged., Conclusions: The exoscope allows adequate exposure of the MCF floor with identification and preservation of key anatomical structures. The exoscope represents a valuable alternative to the microscope in reconstruction of MCF defects, offering high-quality magnification and proven maneuverability., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The epidermal growth factor receptor (EGFR) is a prime oncogene that is frequently amplified in glioblastomas. Here we demonstrate a new tumour-suppressive function of EGFR in EGFR-amplified glioblastomas regulated by EGFR ligands. Constitutive EGFR signalling promotes invasion via activation of a TAB1-TAK1-NF-κB-EMP1 pathway, resulting in large tumours and decreased survival in orthotopic models. Ligand-activated EGFR promotes proliferation and surprisingly suppresses invasion by upregulating BIN3, which inhibits a DOCK7-regulated Rho GTPase pathway, resulting in small hyperproliferating non-invasive tumours and improved survival. Data from The Cancer Genome Atlas reveal that in EGFR-amplified glioblastomas, a low level of EGFR ligands confers a worse prognosis, whereas a high level of EGFR ligands confers an improved prognosis. Thus, increased EGFR ligand levels shift the role of EGFR from oncogene to tumour suppressor in EGFR-amplified glioblastomas by suppressing invasion. The tumour-suppressive function of EGFR can be activated therapeutically using tofacitinib, which suppresses invasion by increasing EGFR ligand levels and upregulating BIN3., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Meniere disease (MD) is an idiopathic peripheral pathology involving the acoustic apparatus. One of the most critical challenges in managing MD is intractable vertigo. In this context, retrosigmoid vestibular neurectomy has been described as a safe and effective technique to manage this symptom when it is resistant to first- and second-line treatments. This article analyzed the alternative treatment options, specific surgical anatomy, and relevant details of vestibular neurectomies performed for intractable MD., Methods: Relevant neurovascular landmarks, critical surgical steps, adequate indications, and potential pitfalls of retrosigmoid vestibular neurectomy were analyzed based on an illustrative clinical case of intractable MD., Results: The illustrative case demonstrated how early recognition of the facial nerve and the vestibulocochlear plane is fundamental to performing retrosigmoid vestibular neurectomy. This procedure is indicated in cases of resistant MD with preoperative hearing integrity. Potential pitfalls of this technique are incomplete neurotomy, nerve regeneration, comorbidities in the contralateral ear, adverse anatomy, the possibility of nonotologic vertigo, and incomplete vestibular compensation., Conclusions: Vestibular neurectomy represents a safe and effective technique to manage MD that is resistant to medical treatment, allowing symptom control and hearing preservation. Nevertheless, detailed knowledge of surgical anatomy and possible pitfalls is of paramount importance to achieve a good outcome., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Historically, creating patient-derived models of lower-grade glioma (LGG) has been challenging, contributing to few experimental platforms that support laboratory-based investigations of this disease. Although organoid modeling approaches have recently been employed to create in vitro models of high-grade glioma (HGG), it is unknown whether this approach can be successfully applied to LGG., Methods: In this study, we developed an optimized protocol for the establishment of organoids from LGG primary tissue samples by utilizing physiologic (5%) oxygenation conditions and employed it to produce the first known suite of these models. To assess their fidelity, we surveyed key biological features of patient-derived organoids using metabolic, genomic, histologic, and lineage marker gene expression assays., Results: Organoid models were created with a success rate of 91% (n = 20/22) from primary tumor samples across glioma histological subtypes and tumor grades (WHO Grades 1-4), and a success rate of 87% (13/15) for WHO Grade 1-3 tumors. Patient-derived organoids recapitulated stemness, proliferative, and tumor-stromal composition profiles of their respective parental tumor specimens. Cytoarchitectural, mutational, and metabolic traits of parental tumors were also conserved. Importantly, LGG organoids were maintained in vitro for weeks to months and reanimated after biobanking without loss of integrity., Conclusions: We report an efficient method for producing faithful in vitro models of LGG. New experimental platforms generated through this approach are well positioned to support preclinical studies of this disease, particularly those related to tumor immunology, tumor-stroma interactions, identification of novel drug targets, and personalized assessments of treatment response profiles., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Society for Neuro-Oncology.)

Background: Distant spread of pituitary adenoma outside the sellar/suprasellar region is classified as pituitary carcinoma. Cerebrospinal fluid (CSF)-born spread of pituitary adenoma can occur after tumor cell spillage into the CSF space after surgery, irradiation, or apoplexy and is not necessarily related to intrinsic tumor biology., Objective: To systematically review the literature and describe the clinical characteristics and treatment strategies of patients with pituitary carcinomas. We further present 2 cases from our institution., Methods: A single-center retrospective review of patients with pituitary adenoma spread to distant intracranial locations between 2000 and 2020 was performed. Electronic databases were searched from their inception to May 25, 2021, and studies describing patients with pituitary spread to distant locations were included., Results: Of 1210 pituitary adenoma cases reviewed, 2 (0.16%) showed tumor spread to distant locations. We found 134 additional cases (from 108 published articles) resulting in a total of 136 cases (61.9% were male). The time to tumor spread ranged between 0 and 516 months (median: 96 months). The follow-up duration ranged between 0 and 240 months (median: 11.5 months). All but 2 patients (98.5%) underwent surgical resection before adenoma spread. The 2 exceptions included a patient with evidence of an apoplectic event on autopsy and another patient with leptomeningeal pituitary spread but an unclear history of apoplexy. Elevated tumor markers were not linked to poor outcomes., Conclusion: Distant spread of pituitary adenoma may occur after surgery, irradiation, or apoplexy. It is not necessarily associated with a malignant clinical course., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Background: Primary central nervous system (CNS) sarcomas represent a heterogeneous group of rare neoplasms with unclear etiology. Available data on clinical characteristics, treatment strategies, and survival are scarce. We comprehensively reviewed management strategies and outcomes of primary CNS sarcomas in adults., Methods: PubMed, Scopus, and Cochrane were search following the PRISMA guidelines to include studies on primary CNS sarcomas in adults. Clinical features, management strategies, and survival were analyzed., Results: We included 9 studies comprising 78 patients. Primary CNS sarcomas were mostly intracranial (87.2%), frequently located in the parietal (17.9%), frontal (14.1%), and temporal (14.1%) lobes. Spinal CNS sarcomas were found in 10 patients (12.8%). The most common tumor histology were fibrosarcoma (16.7%), intracranial synovial sarcoma (12.8%), extraosseous mesenchymal chondrosarcoma (11.5%), perivascular sarcoma (11.5%), reticulum cell sarcoma (11.5%), and myeloid sarcoma (9%). Partial resection (57.7%) was preferred over complete resection (42.3%), and 43 patients (55.1%) received adjuvant treatments: radiotherapy (51.3%) and/or systemic chemotherapy (20.5%). 21 patients experienced CNS sarcomas recurrences, with a median progression-free survival of 9 months (range, 4-48). At last follow-up, 60 patients (76.9%) were dead, with a median overall survival of 9 months (0.1-396). Overall survival was significantly longer in patients with fibrosarcoma (p = 0.001)., Conclusion: Surgical resection coupled with adjuvant chemotherapy or radiation has historically been the cornerstone treatment for CNS sarcoma but showed poor local control and dismal survival. A better understanding of the CNS sarcoma microenvironment may favor the development of tailored strategies aimed at improving survival., (Copyright © 2022. Published by Elsevier B.V.)

Background: Non-functioning pituitary adenomas (NFPA) are often discovered incidentally. The natural history of NFPA is not well understood, obfuscating evidence-based management decisions. Meta-data of radiographically followed NFPA may help guide conservative versus operative treatment of these tumors., Methods: We searched PubMed, Medline, Embase, and Ovid for studies with NFPA managed nonoperatively with radiographic follow-up. Studies on postoperative outcomes after NFPA resection and studies that did not delineate NFPA data from functional pituitary lesions were excluded. NFPA were divided into micro- and macroadenomas based on size at presentation. We performed a meta-analysis of aggregate data for length of follow-up, change in tumor size, rate of apoplexy, and need for resection during follow-up., Results: Our database search yielded 1787 articles, of which 19 were included for final analysis. The studies included 1057 patients with NFPA followed radiographically. Macroadenomas were significantly more likely to undergo growth (34% vs. 12%; p < 0.01) or apoplexy (5% vs. < 1%; p = 0.01) compared to microadenomas. Resection was performed in 11% of all NFPA patients during follow-up regardless of size at presentation. Meta-regression showed that surgery during follow-up was associated with macroadenomas and negatively associated with microadenomas that decreased in size., Conclusion: Low-quality evidence suggests that NFPA classified as macroadenomas have an increased rate of growth and apoplexy during follow-up compared to microadenomas. A significant minority of all NFPA patients ultimately underwent surgery. In select patients, nonoperative management may be the appropriate strategy for NFPA. Macroadenomas may require closer follow-up., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Objective  A variety of endonasal sellar repair techniques have been described; many of which are complex, expensive, and carry potential morbidity but are felt to be necessary to prevent postoperative cerebrospinal fluid (CSF) leaks. We propose an effective, technically simple repair for select sellar defects utilizing an onlay of regenerated oxidized cellulose. Design  Retrospective review of patients from a single neurosurgeon who underwent endoscopic transsphenoidal surgery for pituitary adenoma and sellar reconstruction with only an onlay of regenerated oxidized cellulose. Patients were selected for this repair technique based on the absence of: (1) intraoperative identification of a CSF leak, (2) patulous diaphragm (expanded diaphragm sella herniating to or through sellar floor defect), and (3) other prohibiting comorbidities. Setting  The present study was conducted at a tertiary care center. Participants  In this study, pituitary adenoma patients were the participants. Outcome Measures  Main outcome measure of the study is postoperative CSF leak. Results  A total of 172 patients were identified. Of these, 153 were initial resections of pituitary adenomas. Gross total resection was achieved in 142 (82.6%) cases. Average tumor size was 2.2 ± 1.1 cm. Average tumor volume was 10.4 ± 19.8 cm 3 . No patients had intraoperative CSF leaks. All cases were repaired with only an onlay of regenerated oxidized cellulose. There were two postoperative CSF leaks (1.16%). Pre and postoperative SNOT-22 scores were 12.9 ± 11.9 and 14.3 ± 14.9 ( p  = 0.796), respectively. Conclusion  The use of an onlay of regenerated oxidized cellulose alone is an effective repair technique for select sellar defects. This technique does not result in increased postoperative CSF leak rates and avoids the higher relative cost and potential morbidity associated with more complex, multilayered closures., Competing Interests: Conflict of Interest None declared., (Thieme. All rights reserved.)

Introduction  Decompression of the optic nerve within the optic canal is indicated for compressive visual decline. The two most common approaches utilized for optic canal decompression are a medial approach with an endoscopic endonasal approach and a lateral approach with a craniotomy. Our study is a cadaveric anatomical study comparing the length and circumference of the orbit decompressed via an endoscopic endonasal approach versus a frontotemporal craniotomy. Methods  Five cadaveric specimens were utilized. Predissection computed tomography (CT) scans were performed on each specimen. On each specimen, a standard frontotemporal craniotomy with anterior clinoidectomy and superolateral orbital decompression was performed on one side and an endoscopic endonasal approach with medial wall decompression was performed on the contralateral side. Post-dissection CT scans were performed. An independent radiologist provided measurements of the length (mm) and circumference (degrees) of optic canal decompression bilaterally. Results  The mean length of optic canal decompression for open and endoscopic approach was 13 mm (range 12-15 mm) and 12.4 mm (range 10-16 mm), respectively. The mean circumference of decompression for open and endoscopic approaches was 252.8 degrees (range 205-280 degrees) and 124.6 degrees (range 100-163 degrees), respectively. Conclusion  The endoscopic endonasal and the transcranial approaches provide a similar length of optic canal decompression, but the transcranial approach leads to greater circumferential decompression. The endoscopic endonasal approach has the benefit of being minimally invasive, though. Ultimately, the surgical approach decision should be based on the location of the pathology and the surgeon's comfort., Competing Interests: Conflict of Interest None declared., (Thieme. All rights reserved.)

Chordomas and chondrosarcomas are rare but devastating neoplasms that are characterized by chemoradiation resistance. For both tumors, surgical resection is the cornerstone of management. Immunotherapy agents are increasingly improving outcomes in multiple cancer subtypes and are being explored in chordoma and chondrosarcoma alike. In chordoma, brachyury has been identified as a prominent biomarker and potential molecular immunotherapy target as well as PD-1 inhibition. While studies on immunotherapy in chondrosarcoma are sparse, there is emerging evidence and ongoing clinical trials for PD-1 as well as IDH inhibitors. This review highlights potential biomarkers and targets for immunotherapy in chordoma and chondrosarcoma, as well as current clinical evidence and ongoing trials.

Background: Atypical and anaplastic meningiomas (AAMs) are rare and comprise approximately 5% of all meningiomas. Extracranial metastases in meningioma patients occur in 0.1% of all cases, but these lesions are difficult to treat and may be a poor prognostic factor., Methods: We conducted a retrospective chart review between 1990 and 2016 of patients who had surgical resection of AAM. In a cohort of 149 patients, 6 had metastatic lesions that were histologically confirmed to be meningioma. We compared baseline characteristics between patients with and without metastasis and performed a multivariate Cox regression analysis to assess risk factors for the development of systemic metastasis., Results: Six patients had histologically confirmed meningioma metastasis. We hypothesized that the presence of scalp invasion in patients could be a potential risk factor for the development of systemic meningioma metastasis. Nine out of the 149 patients without metastasis had scalp invasion, whereas 4 out of the 6 patients with metastasis had scalp invasion. Patients with metastasis had a median age of 62 ± 20. Patients without metastasis had a median age of 59 ± 15 years. Gender distribution was similar; approximately 50% of patients in each group were female. Eighty-five percent of patients with metastatic disease were white, and 65% of patients without metastatic disease were white. Among patients without metastatic disease, 77% had World Health Organization II tumors, whereas 50% of patients with metastatic disease had World Health Organization II tumors. In multivariate analysis including age, tumor grade, size, location, extent of resection, sex, and scalp invasion, the only significant predictor of systemic metastasis was scalp invasion (odds ratio = 39.67; 95% confidence interval = 3.74-421.12; P = 0.0023). Median overall survival (OS) with metastasis was 126 months, and median OS without metastasis was 158 months. Having metastatic disease was not significantly associated with worse OS (P = 0.33)., Conclusions: Metastasis development from AAM is a rare but serious event. Because scalp invasion is a strongly associated predictive factor for development of systemic metastasis in patients with AAM, it is necessary to consider strategies to prevent and to be vigilant of the development of scalp invasion., (Published by Elsevier Inc.)