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Chiari malformation type 1 (CM1) is a structural defect that involves the herniation of the cerebellar tonsils through the foramen magnum, causing mild to severe neurological symptoms. Little is known about the molecular and developmental mechanisms leading to its pathogenesis, prompting current efforts to elucidate genetic drivers. Inherited genetic disorders are reported in 2–3% of CM1 patients; however, CM1, including familial forms, is predominantly non-syndromic. Recent work has focused on identifying CM1-asscoiated variants through the study of both familial cases and de novo mutations using exome sequencing. This article aims to review the current understanding of the genetics of CM1. We discuss three broad classes of CM1 based on anatomy and link them with genetic lesions, including posterior fossa-linked, macrocephaly-linked, and connective tissue disorder-linked CM1. Although the genetics of CM1 are only beginning to be understood, we anticipate that additional studies with diverse patient populations, tissue types, and profiling technologies will reveal new insights in the coming years. [ABSTRACT FROM AUTHOR]

Background: Epidermoid tumors of the cerebellopontine angle and posterior fossa account for approximately 1% of all intracranial tumors. Classifications that may guide surgical planning in the current neurosurgical practice are lacking. This study aimed to focus on the surgical outcome and suggest a classification system that may aid neurosurgeons in determining the goal of resection to minimize morbidity and mortality rates. Methods: The study population comprised patients who underwent surgery and follow-up for tissue-proven epidermoid tumors between 2015 and 2020. Patients' data, including demographic features, clinical symptomatology, the extent of surgical resection, and postoperative outcomes, were retrospectively evaluated. A new classification system was designed based on the anatomical–radiological findings and was evaluated in terms of clinical symptomatology, radiological features, surgical approach, and postoperative outcomes. Results: The patient population comprised 22 women (57.9%) and 16 men (42.1%), with a mean age of 34.9 years. A practical classification system based on the radiological–anatomical vertical (1, 2, and 3) and horizontal (a, b, and c) tumor extensions was designed. No significant differences were found in the patients in terms of sex/age. The most commonly observed symptom was gait disturbance (34.2%). The preoperative tumor diameter was significantly larger in the subtotal resection (STR) group than in the gross total resection (GTR) and near-total resection (NTR) groups. Significantly more cistern involvement was observed in the STR group than in the GTR group. The GTR, NTR, and STR rates were higher in grade 1, 3, and 2 cases, respectively. The subgroup 'a' was correlated with higher resection rates (GTR and NTR), whereas the subgroup 'b' was correlated with STR. Conclusions: Our suggested classification system represents a simple and practical model that may guide neurosurgeons in predicting the goal of resection during surgical planning and in minimizing potential morbidity. [ABSTRACT FROM AUTHOR]

Introduction: Chiari malformation (CIM) is a congenital anomaly characterized by herniation of hindbrain structures through the foramen magnum into the cervical spinal canal (CSC). Although the pathogenesis of CIM has not been clearly defined, its relationship with the posterior fossa and CSC morphology is unclear. In this study, we aimed to perform morphometric analysis of both the posterior fossa and the CSC in CIM to investigate the correlation of measurements with each other and to reveal their effects on the development of syringomyelia (SM), which has not been previously reported. Methods: Magnetic resonance imaging images of 90 patients and 30 healthy individuals were retrospectively analyzed. Posterior fossa parameters and CSC diameters at all cervical vertebral levels were measured for each patient. The taper ratio of CSC was calculated separately for each group at the C1-C4 and C1-C7 levels. The average CSC shape was drawn for each group. Results: No statistically significant difference was detected between the age groups. A steeper taper ratio was detected when CIM was accompanied by SM. In addition, the posterior fossa had a narrower volume than the normal fossa in CIM. Conclusion: Morphometric analysis of both the posterior fossa and the CSC was performed using CIM for the first time in the literature. This is the first study to present the term "tapering" with an illustration. [ABSTRACT FROM AUTHOR]

Purpose: The Posterior Fossa Society, an international multidisciplinary group, hosted its first global meeting designed to share the current state of the evidence across the multidisciplinary elements of pediatric post-operative cerebellar mutism syndrome (pCMS). The agenda included keynote talks from world-leading speakers, compelling abstract presentations and engaging discussions led by members of the PFS special interest groups. Methods: This paper is a synopsis of the first global meeting, a 3-day program held in Liverpool, England, UK, in September 2022. Results: Topics included nosology, patient and family experience, cerebellar modulation of cognition, and cerebellar cognitive affective syndrome. In addition, updates from large-scale studies were shared as well as abstracts across neuroradiology, neurosurgery, diagnosis/scoring, ataxia, and rehabilitation. Conclusions: Based on data-driven evidence and discussions, each special interest group created research priorities to target before the second global meeting, in the spring of 2024. [ABSTRACT FROM AUTHOR]

The central nervous system (CNS) is less prone to infection owing to protection from the brain-blood barrier. However, craniotomy destroys this protection and increases the risk of infection in the brain of patients who have undergone craniotomy. CNS infection after craniotomy significantly increases the patient's mortality rate and disability. Controlling the occurrence of intracranial infection is very important for post-craniotomy patients. CNS infection after craniotomy is caused by several factors such as preoperative, intraoperative, and post-operative factors. Craniotomy may lead to postsurgical intracranial infection, which is mainly associated with surgery duration, infratentorial (posterior fossa) surgery, cerebrospinal fluid leakage, drainage tube placement, unregulated use of antibiotics, glucocorticoid use, age, diabetes, and other systemic infections. Understanding the risk factors of CNS infection after craniotomy can benefit reducing the incidence of intracranial infectious diseases. This will also provide the necessary guidance and evidence in clinical practice for planning to control intracranial infection in patients with craniotomy. [ABSTRACT FROM AUTHOR]

Simple Summary: Neuronavigation and microscope-based augmented reality are widely used in neurosurgery to support intraoperative orientation, preserve neurological function, and maximize the extent of resection. However, in the sitting position, navigation may not be accurate enough to fully exploit its potential due to brain deformations caused by gravity and brain shift. To ensure accurate navigation and augmented reality support, it is necessary to verify and update navigation regularly. Intraoperative ultrasound is an easy-to-use tool that can be used to verify accuracy and to generate real-time image data to update navigation without significantly interrupting the surgical workflow. This can be achieved by outlining the lesion within the data set or by rigidly co-registering preoperative and intraoperative data to update and enable navigation and augmented reality support. In this study, image-based co-registration improved the navigation accuracy, making intraoperative ultrasound useful for enabling navigation and augmented reality support during posterior fossa surgery in the sitting position. Despite its broad use in cranial and spinal surgery, navigation support and microscope-based augmented reality (AR) have not yet found their way into posterior fossa surgery in the sitting position. While this position offers surgical benefits, navigation accuracy and thereof the use of navigation itself seems limited. Intraoperative ultrasound (iUS) can be applied at any time during surgery, delivering real-time images that can be used for accuracy verification and navigation updates. Within this study, its applicability in the sitting position was assessed. Data from 15 patients with lesions within the posterior fossa who underwent magnetic resonance imaging (MRI)-based navigation-supported surgery in the sitting position were retrospectively analyzed using the standard reference array and new rigid image-based MRI-iUS co-registration. The navigation accuracy was evaluated based on the spatial overlap of the outlined lesions and the distance between the corresponding landmarks in both data sets, respectively. Image-based co-registration significantly improved (p < 0.001) the spatial overlap of the outlined lesion (0.42 ± 0.30 vs. 0.65 ± 0.23) and significantly reduced (p < 0.001) the distance between the corresponding landmarks (8.69 ± 6.23 mm vs. 3.19 ± 2.73 mm), allowing for the sufficient use of navigation and AR support. Navigated iUS can therefore serve as an easy-to-use tool to enable navigation support for posterior fossa surgery in the sitting position. [ABSTRACT FROM AUTHOR]

A 62-year-old man was referred for a transorbital injury. A preoperative computed tomography scanner confirmed an 8 cm long × 14 mm wooden piece penetrating the right orbit and perforating the anterior cranial base until the frontal lobe with no apparent prominent vascular injury. However, an unexpected posterior fossa tumor causing blocked hydrocephalus was unveiled. Extraction of the wooden stick was safely achieved after intracranial exploration followed by meticulous cleaning and careful watertight closure to prevent cerebrospinal fluid (CSF) leakage. Except the right eyesight loss, he initially recovered well, were it not for his hard-to-treat hydrocephalus. What at the time of its discovery seemed to be a less important but very likely the indirect cause of its injury, became unexpectedly problematic. Despite all CSF diversion procedures, the patient worsened gradually. Neither a failed attempt to remove the tumor due to the fourth ventricle floor broad infiltration nor the posterior fossa decompressive craniectomy succeeded in improving his neurological status. Despite the diagnosis of a grade II ependymoma, the tumor demonstrated an aggressive radiological behavior with an intense edema of the brainstem, possibly the cause of his drowsiness. Unfortunately, he died of tumor progression solely 52 days after his transorbital injury. [ABSTRACT FROM AUTHOR]

Background: Segmentation tools continue to advance, evolving from manual contouring to deep learning. Researchers have utilized segmentation to study a myriad of posterior fossa-related conditions, such as Chiari malformation, trigeminal neuralgia, post-operative pediatric cerebellar mutism syndrome, and Crouzon syndrome. Herein, we present a summary of the current literature on segmentation of the posterior fossa. The review highlights the various segmentation techniques, and their respective strengths and weaknesses, employed along with objectives and outcomes of the various studies reported in the literature. Methods: A literature search was conducted in PubMed, Embase, Cochrane, and Web of Science up to November 2023 for articles on segmentation techniques of posterior fossa. The two senior authors searched through databases based on the keywords of the article separately and then enrolled joint articles that met the inclusion and exclusion criteria. Results: The initial search identified 2205 articles. After applying inclusion and exclusion criteria, 77 articles were selected for full-text review after screening of titles/abstracts. 52 articles were ultimately included in the review. Segmentation techniques included manual, semi-automated, and fully automated (atlas-based, convolutional neural networks). The most common pathology investigated was Chiari malformation. Conclusions: Various forms of segmentation techniques have been used to assess posterior fossa volumes/pathologies and each has its advantages and disadvantages. We discuss these nuances and summarize the current state of literature in the context of posterior fossa-associated pathologies. [ABSTRACT FROM AUTHOR]

Introduction Emotional lability (EL), the uncontrollable and unmotivated expression of emotion, is a rare and distressing symptom of brainstem compression. In published case reports, EL from an extra-axial posterior fossa tumor was alleviated by tumor resection. The primary aim herein was to radiographically establish the degree of compression from mass lesions onto brainstem structures. Secondarily, we compared changes in patient-reported quality of life (QOL) pre- and postoperatively. Methods A retrospective review of posterior fossa tumors treated between 2002 and 2018 at Vancouver General Hospital revealed 11 patients with confirmed EL. Each case was matched to three controls. A lateral brainstem compression scale characterized mass effect at the level of the medulla, pons, and midbrain in preoperative axial T2-weighted fluid-attenuated inversion recovery magnetic resonance imaging (FLAIR MRI) scans. Compression and clinical variables were compared between patient groups. Short Form-36 version 1 health surveys were retrospectively obtained from patient charts to compare pre- versus postoperative changes in survey scores between EL and control patients. Results EL symptoms ceased postoperatively for all EL patients. EL tumors exert greater compression onto the pons (p = 0.03) and EL patients more commonly have cerebellar findings preoperatively (p = 0.003). Patients with EL-causing tumors experienced greater improvement postoperatively in "Health Change" (p = 0.05), which was maintained over time. Conclusion Findings suggest that compression onto the pons inhibits control over involuntary, stereotyped expression of emotion. This adds to evidence that EL may be attributed to cerebellum deafferentation from cortical and limbic structures through the basis pontis, leading to impaired modulation of emotional response. QOL results augment benefits of offering patients EL-alleviating tumor resection surgery. [ABSTRACT FROM AUTHOR]

Introduction Safe, effective access to the fourth ventricle for oncologic resection remains challenging given the depth of location, restricted posterior fossa boundaries, and surrounding eloquent neuroanatomy. Despite description in the literature, a practical step-by step dissection guide of the suboccipital approaches to the fourth ventricle targeted to all training levels is lacking. Methods Two formalin-fixed, latex-injected specimens were dissected under microscopic magnification and endoscopic visualization. Dissections of the telovelar, transvermian, and supracerebellar infratentorial-superior transvelar approaches were performed by one neurosurgery resident (D.D.D.), under guidance of senior authors. The dissections were supplemented with representative clinical cases to highlight pertinent surgical principles. Results The telovelar and transvermian corridors afford excellent access to the caudal two-thirds of the fourth ventricle with the former approach offering expanded access to the lateral recess, foramen of Luschka, adjacent skull base, and cerebellopontine angle. The supracerebellar infratentorial-superior transvelar approach reaches the rostral third of the fourth ventricle, the cerebral aqueduct, and dorsal mesencephalon. Key steps described include positioning and skin incision, myofascial dissection, burr hole and craniotomy, durotomy, the aforementioned transventricular routes, and identification of relevant skull base landmarks. Conclusion The midline suboccipital craniotomy represents a foundational cranial approach, particularly for lesions involving the fourth ventricle. Operatively oriented resources that combine stepwise neuroanatomic dissections with representative cases provide a crucial foundation for neurosurgical training. We present a comprehensive guide for trainees in the surgical anatomy laboratory to optimize familiarity with fourth ventricle approaches, mastery of relevant microsurgical anatomy, and simultaneous preparation for learning in the operating room. [ABSTRACT FROM AUTHOR]

Introduction: Posterior fossa extradural hematoma (PFEDH) is an infrequent occurrence in traumatic brain injuries, constituting approximately 4-7% of all extradural hematomas (EDHs). Despite its rarity, PFEDH demands urgent attention as it can swiftly lead to a fatal outcome unless promptly identified and addressed. The posterior fossa's confined space means that even a relatively small hematoma volume can result in clinical deterioration. Early detection through cranial computed tomography is imperative, and immediate evacuation is essential for a positive prognosis. The critical nature of PFEDH underscores the necessity for rapid intervention to prevent irreversible neurological damage and reduce the risk of mortality. Materials and methods: This study was conducted at Department of Neurosurgery, Gajra Raja Medical College, Gwalior, Madhya Pradesh, India from a period of July 2021 to June 2023 of 23 cases of PFEDHs. Records of patients with PFEDHs were reviewed for the mode of injury, Glasgow Coma Scale (GCS) at admission, imaging, type of intervention, outcome, and follow-up. GCS was assessed at 6 months. Results: Of these 23 patients, 17 were males and 6 females. The mean age of patients was 25 year .12 patients had GCS 15 at admission, and only 4 of them had GCS <8. Mean EDH volume was 25 ml. 20 patients were operated, 3 managed conservatively. 21 patients were discharged, Two patients died. At 6 months follow-up, 20 patients had good reovery (Glasgow Outcome Score [GOS] 5). Conclusions: Posterior fossa extradural hematomas (PFEDH) are uncommon occurrences often linked with occipital bone fractures and occasionally accompanied by supratentorial hematomas. The rapid fatality of PFEDH results from hematoma expansion, which compromises the limited space in the posterior cranial fossa. This compression can lead to severe consequences such as brainstem compression, tonsillar herniation, and obstructive hydrocephalus. Timely identification and urgent evacuation through medical intervention are pivotal for a positive outcome in PFEDH cases. [ABSTRACT FROM AUTHOR]

Objectives: Our objectives were: (1) to assess the visualization rate of the choroid bar in a consecutive series of 306 first‐trimester scans; (2) to verify, in this cohort of fetuses, the normality of the posterior fossa later in pregnancy; and (3) to confirm the non‐visualization of the choroid bar in a retrospective series of fetuses with posterior fossa malformations. Methods: This study included a prospective and a retrospective series. The former comprised 306 fetuses undergoing routine obstetric ultrasound at our unit in both the first and second trimesters over a 6‐month period, while the latter comprised 12 cases of posterior fossa malformations. In the prospective study, the presence of the choroid bar, which is defined as a visually continuous, homogeneously hyperechogenic, thick structure bridging the cisterna magna from side to side, was evaluated at the end of the first‐trimester nuchal translucency scan. In the retrospective study, previously acquired three‐dimensional volume datasets were processed in order to assess whether the choroid bar could be visualized in cases of open spinal dysraphisms and vermian cystic anomalies. In the prospective study, confirmation of a normal posterior fossa was based on the sonographic features of this anatomical region at the time of the second‐trimester anomaly scan at 19–21 weeks' gestation, while, in the retrospective study, it was based on autopsy results, when available, or further direct imaging of the defect later in pregnancy. Results: In the prospective study, the choroid bar could be visualized in all 306 fetuses, on transabdominal ultrasound in 287 (93.8%) cases and on transvaginal ultrasound in 19 (6.2%) cases. The choroid bar was displayed with a ventral/dorsal approach in 67 (21.9%) cases, with a lateral approach in 56 (18.3%) cases and with both in 183 (59.8%) cases. All 306 cases were confirmed to have a sonographically normal posterior fossa at 19–21 weeks. On the other hand, in the retrospective study, it was not possible to visualize the choroid bar in any of the fetuses with posterior fossa malformations. Conclusions: We have described a new sign, the choroid bar, consistent with a normal posterior fossa at 12–14 weeks' gestation. The choroid bar provides the option of screening for major abnormalities of the posterior fossa, since its absence raises suspicion of both open spinal dysraphisms and posterior fossa cystic malformations. At the same time, it is easy to visualize, as it can be seen with all lines of insonation. © 2023 International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

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Objective: Lesions of the posterior fossa (brainstem and cerebellum) are challenging in diagnosis and treatment due to the fact that they are often located eloquently and total resection is rarely possible. Therefore, frame-based stereotactic biopsies are commonly used to asservate tissue for neuropathological diagnosis and further treatment determination. The aim of our study was to assess the safety and diagnostic success rate of frame-based stereotactic biopsies for lesions in the posterior fossa via the suboccipital-transcerebellar approach. Methods: We performed a retrospective database analysis of all frame-based stereotactic biopsy cases at our institution since 2007. The aim was to identify all surgical cases for infratentorial lesion biopsies via the suboccipital-transcerebellar approach. We collected clinical data regarding outcomes, complications, diagnostic success, radiological appearances, and stereotactic trajectories. Results: A total of n = 79 cases of stereotactic biopsies for posterior fossa lesions via the suboccipital-transcerebellar approach (41 female and 38 male) utilizing the Zamorano-Duchovny stereotactic system were identified. The mean age at the time of surgery was 42.5 years (± 23.3; range, 1–87 years). All patients were operated with intraoperative stereotactic imaging (n = 62 MRI, n = 17 CT). The absolute diagnostic success rate was 87.3%. The most common diagnoses were glioma, lymphoma, and inflammatory disease. The overall complication rate was 8.7% (seven cases). All patients with complications showed new neurological deficits; of those, three were permanent. Hemorrhage was detected in five of the cases having complications. The 30-day mortality rate was 7.6%, and 1-year survival rate was 70%. Conclusions: Our data suggests that frame-based stereotactic biopsies with the Zamorano-Duchovny stereotactic system via the suboccipital-transcerebellar approach are safe and reliable for infratentorial lesions bearing a high diagnostic yield and an acceptable complication rate. Further research should focus on the planning of safe trajectories and a careful case selection with the goal of minimizing complications and maximizing diagnostic success. [ABSTRACT FROM AUTHOR]

Posterior fossa tumors are the most common pediatric brain tumors, and present unique challenges in terms of their location and surgical management. The posterior fossa comprehends complex anatomy and represents the smallest and deepest of the three cranial base fossae. An in-depth understanding of posterior fossa anatomy is crucial when it comes to the surgical resection of pediatric brain tumors. Mastering the knowledge of posterior fossa anatomy helps the neurosurgeon in achieving a maximal and safe volumetric resection, that impacts in both overall and progression free survival. With the advancements in microsurgery, the telovelar approach has emerged as the workhorse technique for the resection of posterior fossa tumors in pediatric patients. This approach involves meticulously dissecting of the natural clefts present in the cerebellomedullary fissure, making a comprehensive understanding of the underlying anatomy key for its success. [ABSTRACT FROM AUTHOR]

Purpose: To review a multicentric series of lateral-type posterior fossa ependymomas operated in the last ten years and to analyze the factors related to clinical evolution and tumor survival. Methods: Descriptive, retrospective study. Active members of the Spanish Society of Pediatric Neurosurgery were invited to participate in this multicentric study. Clinical and radiological data were incorporated to an open database. The role of histologic grade, grade of resection, postoperative morbidities, and clinical follow-up was evaluated through bivariate associations (chi-square), Kaplan–Meier's curves (log-rank test), and multivariate analysis (binary logistic regression). Results: Fourteen centers entered the study, and 25 cases with a minimum follow-up of 6 months were included. There were 13 boys and 12 girls with a mean age close to 3 years. Mean tumor volume at diagnosis was over 60 cc. A complete resection was achieved in 8 patients and a near-total resection in 5 cases. Fifteen tumors were diagnosed as ependymoma grade 2 and ten as ependymoma grade 3. Major morbidity occurred postoperatively in 14 patients but was resolved in twelve within 6 months. There were six cases of death and 11 cases of tumor progression along the observation period. Mean follow-up was 44.8 months. Major morbidity was significantly associated with histologic grade but not with the degree of resection. Overall and progression-free survival were significantly associated with complete surgical resection. At the last follow-up, 16 patients carried a normal life, and three displayed a mild restriction according to Lansky's scale. Conclusions: Lateral-type posterior fossa ependymomas constitute a specific pathologic and clinical tumor subtype with bad prognosis. Gross total resection is the goal of surgical treatment, for it significantly improves prognosis with no additional morbidity. Neurological deficits associated to lower cranial nerve dysfunction are common, but most are transient. Deeper genetic characterization of these tumors may identify risk factors that guide new treatments and stratification of adjuvant therapies. [ABSTRACT FROM AUTHOR]

Objective: Lesions of the posterior fossa (brainstem and cerebellum) are challenging in diagnosis and treatment due to the fact that they are often located eloquently and total resection is rarely possible. Therefore, frame-based stereotactic biopsies are commonly used to asservate tissue for neuropathological diagnosis and further treatment determination. The aim of our study was to assess the safety and diagnostic success rate of frame-based stereotactic biopsies for lesions in the posterior fossa via the suboccipital-transcerebellar approach. Methods: We performed a retrospective database analysis of all frame-based stereotactic biopsy cases at our institution since 2007. The aim was to identify all surgical cases for infratentorial lesion biopsies via the suboccipital-transcerebellar approach. We collected clinical data regarding outcomes, complications, diagnostic success, radiological appearances, and stereotactic trajectories. Results: A total of n = 79 cases of stereotactic biopsies for posterior fossa lesions via the suboccipital-transcerebellar approach (41 female and 38 male) utilizing the Zamorano-Duchovny stereotactic system were identified. The mean age at the time of surgery was 42.5 years (± 23.3; range, 1–87 years). All patients were operated with intraoperative stereotactic imaging (n = 62 MRI, n = 17 CT). The absolute diagnostic success rate was 87.3%. The most common diagnoses were glioma, lymphoma, and inflammatory disease. The overall complication rate was 8.7% (seven cases). All patients with complications showed new neurological deficits; of those, three were permanent. Hemorrhage was detected in five of the cases having complications. The 30-day mortality rate was 7.6%, and 1-year survival rate was 70%. Conclusions: Our data suggests that frame-based stereotactic biopsies with the Zamorano-Duchovny stereotactic system via the suboccipital-transcerebellar approach are safe and reliable for infratentorial lesions bearing a high diagnostic yield and an acceptable complication rate. Further research should focus on the planning of safe trajectories and a careful case selection with the goal of minimizing complications and maximizing diagnostic success. [ABSTRACT FROM AUTHOR]

Copyright of Hamidiye Medical Journal is the property of Galenos Yayinevi Tic. LTD. STI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Although uncommon, cerebellar contusions are associated with significant morbidity and mortality. Literature is lacking in the prognostic and morphological factors relating to their clinical picture and outcomes, especially within children. The objective of this study is to evaluate prognostic and anatomic factors in the clinical picture of cerebellar contusions, including effacement of the 4th ventricle and cisterna magna. Methods: This is a retrospective chart review over 11 years across two medical centers. Patients included were under 18 years who presented with a cerebellar contusion. Patients were stratified within the study group based on discharge Glasgow outcome scale (GOS) and reviewed for prognostic factors contributing to outcome. Mid sagittal area of the 4th ventricle and cisterna magna were measured using magnetic resonance imaging and compared within the groups. Results: A total of 21 patients met the study criteria, of which 16 (76.2%) were male, with an average patient age of 8.65 years. Poor outcome at discharge (GOS <4) was associated with decreased admission Glasgow coma scale (P = 0.003), admission motor response (P = 0.006), pupil reactivity (P = 0.014), presence of concomitant subarachnoid hemorrhage (P = 0.010), contusion volume (P < 0.001), and decreased area of the cisterna magna (P = 0.012). Patients with poor outcomes were also more likely to require surgical intervention (P = 0.042). Conclusion: There are multiple prognostic factors associated with the overall outcome following cerebellar contusions. The rate of good outcomes in this study was superior to that in previous studies in adults. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, we reviewed and analyzed various radiomics models used to identify three of the most common pediatric posterior fossa tumors: medulloblastoma, pilocytic astrocytoma, and ependymoma. We wanted to understand how well these models worked overall. By examining a range of studies, we found that the models could effectively distinguish between these tumor types with high accuracy. Certain types of models and specific features in the images seemed to perform better. The findings suggest that these models can be very useful in accurately diagnosing these pediatric brain tumors. This research could lead to even more precise models in the future. Purpose: To better define the overall performance of the current radiomics-based models for the discrimination of pediatric posterior fossa tumors. Methods: A comprehensive literature search of the databases PubMed, Ovid MEDLINE, Ovid EMBASE, Web of Science, and Scopus was designed and conducted by an experienced librarian. We estimated overall sensitivity (SEN) and specificity (SPE). Event rates were pooled across studies using a random-effects meta-analysis, and the χ2 test was performed to assess the heterogeneity. Results: Overall SEN and SPE for differentiation between MB, PA, and EP were found to be promising, with SEN values of 93% (95% CI = 0.88–0.96), 83% (95% CI = 0.66–0.93), and 85% (95% CI = 0.71–0.93), and corresponding SPE values of 87% (95% CI = 0.82–0.90), 95% (95% CI = 0.90–0.98) and 90% (95% CI = 0.84–0.94), respectively. For MB, there is a better trend for LR classifiers, while textural features are the most used and the best performing (ACC 96%). As for PA and EP, a synergistic employment of LR and NN classifiers, accompanied by geometrical or morphological features, demonstrated superior performance (ACC 94% and 96%, respectively). Conclusions: The diagnostic performance is high, making radiomics a helpful method to discriminate these tumor types. In the forthcoming years, we expect even more precise models. [ABSTRACT FROM AUTHOR]

Background: Neurovascular relationships in the posterior fossa are more frequently investigated due to the increasing availability of 3.0 Tesla MRI. For an assessment with 3D visualization, no systematic analyzes are available so far and the question arises as to whether 3.0 Tesla MRI should be given preference over 1.5 Tesla MRI. Methods: In a prospective study, a series of 25 patients each underwent MRI investigations with 3D-CISS and 3D-TOF at 1.5 and 3.0 Tesla. For both field strengths separately, blood vessel information from the TOF data was fused into the CISS data after segmentation and registration. Four visualizations were created for each field strength, with and without optimization before and after fusion, which were evaluated with a rating system and verified with the intraoperative situation. Results: When only CISS data was used, nerves and vessels were better visualized at 1.5 Tesla. After fusion, flow and pulsation artifacts were reduced in both cases, missing vessel sections were supplemented at 3.0 Tesla and 3D visualization at 1.5 and 3.0 Tesla led to anatomically comparable results. By subsequent manual correction, the remaining artifacts were further eliminated, with the 3D visualization being significantly better at 3.0 Tesla, since the higher field strength led to sharper contours of small vessel and nerve structures. Conclusion: 3D visualizations at 1.5 Tesla are sufficiently detailed for planning microvascular decompression and can be used without restriction. Fusion further improves the quality of 3D visualization at 3.0 Tesla and enables an even more accurate delineation of cranial nerves and vessels. [ABSTRACT FROM AUTHOR]

Background: Chiari I malformation is defined by tonsillar herniation through the foramen magnum. There is no consensus on the treatment of Chiari malformation. A simple follow-up is recommended for asymptomatic cases. The classic approach is the midline sub-occipital craniotomy. Methods: For four years, we operated on six patients with Chiari malformation I using our endoscopic minimally invasive sub-occipital approach. We compared the results with six other patients operated by the classical sub-occipital approach. Results: Patients operated by endoscopic approach had shorter hospital stays, and wounds healed faster and smoother. Mid-term results were similar in the two groups. Conclusion: This paper proposes a new endoscopic Minimally invasive paramedian sub-occipital approach for Chiari malformation I. Although the number of cases is limited, the results look promising. We need to gather more cases to have significant numbers to perform a global comparison between the two approaches and assess the advantages and disadvantages of each technique. [ABSTRACT FROM AUTHOR]

Chiari malformation (CM) is characterized by herniation of the cerebellar tonsil(s) and/or medulla oblongata into the spinal canal, resulting in various morphometric abnormalities. The current study aimed to evaluate the magnetic resonance imaging (MRI) findings and morphometric features of the craniocervical region in patients who underwent surgery for CM. Demographic and radiological data were collected from 59 patients who underwent surgery for CM and a control group of 58 randomly selected nonsurgical patients. For between-group comparisons, Continuous variables were described as the mean (±SD) or median (IQR) and categorical variables as frequency (%). The mean age of the control group participants was 33.38 years. The mean age of patients in the CM group at the time of surgery was 33.83 years. The diameter of the foramen magnum, the maximum anteroposterior diameter of the C1 vertebra, the maximum diameter of the spinal canal at the C2 vertebra, and the atlantodental interval were all positively correlated with the total cerebellar tonsil length [r=0.54, 0.37, 0.42, 0.71]. Comparisons of total cerebellar tonsil length with other morphological and clinical variables, including contact between the brainstem and clivus, basilar invagination, preoperative hydrocephalus, remnant cartilage between the odontoid and C2 corpus, and associated craniovertebral junction anomalies, revealed no other significant correlations. CM is associated with many structural anomalies in the brain. However, there is relatively little detail in the existing literature on the morphometric parameters associated with the malformation. The findings of this study provide insights for future research and contribute to knowledge of the morphometric features of CMs in general and CMs in patients requiring surgical management in particular. [ABSTRACT FROM AUTHOR]

Background Hemangioblastomas pose an inherent surgical risk due to the potential for high intraoperative blood loss, especially in larger tumors. One approach to minimize this risk is to use preoperative embolization. Herein, we present our institutional experience treating large and giant cerebellar hemangioblastomas. Methods We performed a retrospective chart review of 19 patients with cerebellar hemangioblastomas that had a maximal diameter of >3 cm. We performed a literature review and included individual patient-level data that met our >3 cm diameter cerebellar hemangioblastoma inclusion criteria. Results Our cohort consisted of 19 patients that received a total of 20 resections for their cerebellar hemangioblastomas. Preoperative embolization was utilized in eight cases (38.1%). One patient experienced transient neurological complications after embolization (12.5%). Tumors of patients in the embolization group had larger median total, solid, and cystic volumes and were more likely to involve the cerebellopontine angle than those in the non-embolized group. Compared with non-embolized patients, embolized patients had less decrease in their hemoglobin, lower volumes of estimated blood loss, reduced rates of postoperative complications and permanent deficits, and greater instances of neurological improvement. The larger cohort (obtained from the combining our cohort with patients identified during a literature review) consisted of 99 patients with 39 receiving preoperative embolization. Conclusion It is important to examine individual patient characteristics when determining eligibility for preoperative embolization. However, improvements in endovascular techniques have made preoperative embolization a safe and effective procedure with minimal risks that can be performed in many patients. [ABSTRACT FROM AUTHOR]

Cerebellar ischemic stroke (CIS) is a morbid neurological event, with potentially fatal consequences. There is currently no objective standard of care regarding when surgical procedures are required for this entity. We retrospectively reviewed 763 patients with CIS, 247 patients of which had a stroke larger than 1 cm in greatest dimension on cranial imaging. In this subgroup, 11% of patients received ventriculostomy, 12% suboccipital craniectomy, and 9% mechanical endovascular thrombectomy. Various clinical and radiographic variables were examined for relationship to surgical procedures, 30-day mortality rate, and modified Rankin scores. The smallest volume of stroke requiring a surgical procedure was 15.5 mL3 (BrainLab Software). Patients receiving surgical procedures had a higher incidence of multi-territory infarctions, hydrocephalus, cistern compression, 4th ventricular compression, as well as younger age, lower admission GCS, higher admission NIHSS, and higher 30-day mortality/disability. Patients deemed to require surgical procedures for CIS have a higher expected morbidity and mortality than those not requiring surgery. Various clinical and radiographic variables, including stroke volume, can be used to guide selection of patients requiring surgery. [ABSTRACT FROM AUTHOR]

The Anterior Inferior Cerebellar Artery-Posterior Inferior Cerebellar Artery (AICA-PICA) common trunk is a rare variant of cerebral posterior circulation in which a single vessel originating from either the basilar or vertebral arteries supplies both cerebellum and brainstem territories. We present the first case of an unruptured right AICA-PICA aneurysm treated with flow diversion using a Shield-enhanced pipeline endovascular device (PED, VANTAGE Embolization Device with Shield Technology, Medtronic, Canada). We expand on this anatomic variant and review the relevant literature. A 39-year-old man presented to our treatment center with vertigo and right hypoacusis. The initial head CT/CTA was negative, but a 4-month follow-up MRI revealed a 9 mm fusiform dissecting aneurysm of the right AICA. The patient underwent a repeat head CTA and cerebral angiogram, which demonstrated the presence of an aneurysm on the proximal portion of an AICA-PICA anatomical variant. This was treated with an endovascular approach that included flow diversion via a PED equipped with Shield Technology. The patient's post-procedure period was uneventful, and he was discharged home after two days with an intact neurological status. The patient is still asymptomatic after a 7-month follow-up, with MR angiogram evidence of stable aneurysm obliteration and no ischemic lesions. Aneurysms of the AICA-PICA common trunk variants have a high morbidity risk due to the importance and extent of the territory vascularized by a single vessel. Endovascular treatment with flow diversion proved to be both safe and effective in obliterating unruptured cases. [ABSTRACT FROM AUTHOR]

Chronic subdural hematoma (CSH) in the posterior fossa is extremely rare in the adult population. CT scanning is generally accurate and sufficiently sensitive in the diagnosis of supratentorial subdural hematomas, while MRI has clearly shown its superiority in the detection of subdural collections at unusual locations and particularly in the detailed analysis of the posterior cranial fossa. The surgical strategy is still controversial. We report a case of CSH in the posterior fossa successfully treated with a suboccipital craniectomy. A 70-year-old man; has developed headaches, nausea, cerebellar syndrome and ataxia of walking. Radiological examinations revealed the appearance of a right CSH in the posterior fossa associated with hydrocephalus. Upon rapid deterioration of the patient's consciousness, urgent treatment was required. A small right suboccipital craniectomy was to access the hematoma. Postoperative computed tomography showed that the CSH and hydrocephalus had been successfully treated. [ABSTRACT FROM AUTHOR]

While comprising only 2% of all ischemic strokes, cerebellar strokes are responsible for substantial morbidity and mortality due to their subtle initial presentation and the morbidity of posterior fossa swelling. Furthermore, low temporal muscle thickness (TMT) has recently been identified as a prognostic imaging parameter to assess patient frailty and outcome. We analyzed radiological and clinical data sets of 282 patients with cerebellar ischemic stroke. Our analysis showed a significant association between low TMT, reduced NIHSS and mRS at discharge (p = 0.035, p = 0.004), and reduced mRS at 12 months (p = 0.001). TMT may be used as a prognostic imaging marker and objective tool to assess outcomes in patients with cerebellar ischemic stroke. [ABSTRACT FROM AUTHOR]

Background: The anterior transpetrosal approach (ATPA) is a cranial base approach for addressing upper petroclival or lateral pontine lesions. It is fundamentally an epidural procedure involving the drilling of the petrous apex. However, this approach has significant procedure-related morbidity, and the surgeon must perform a complete petrosectomy, as the intradural structures are not in view during the drilling. For selected cases, a rationale exists for choosing a tailor-made intradural anterior petrosectomy (IAP). Method: This article describes the relevant surgical anatomy and the different surgical steps of the IAP. Conclusion: IAP represents a feasible alternative to the standard ATPA with the advantage of minimizing the extent of petrous bone removal to the individual need. [ABSTRACT FROM AUTHOR]

Background: Here, we sought to examine the validity and reproducibility of balanced fast field echo (bFFE) for assessing superior petrosal vein (SPV) complex (SPVC) anatomy. Methods: Preoperative bFFE or equivalent scans and operative videos were studied and directly compared with regard to the individual anatomical features of SPVCs and their relation to the operative field. The anatomical details of the bFFE findings of the non-operated side (group 2) of all 50 patients were then reviewed, including the presence of petrosal–galenic anastomosis, and finally compared to the operated SPVCs (group 1). Results: A complete correlation between bFFE and intraoperative findings was observed in 62% of cases and had a significant correlation with 3 Tesla magnet strength and higher pixel bandwidth (rbis = − 0.47; p = 0.005). The sensitivity and specificity of bFFE magnetic resonance imaging were 93.7 and 95.2%, respectively, for detecting an SPV disturbing the operative field, and 97.3% and 95% for a disturbing tributary, respectively. Each group had 50 SPVCs, with a total of 70 and 64 SPVs, 10 and 11 general SPVC configurations, as well as 29 and 28 different individual anatomical variations in groups 1 and 2, respectively. Both groups had 1–3 SPVs with a similar distribution of frequencies [Chi-square (4) = 27.56; p = 0.0145 (Fisher's exact test)]. The similarity of the general configurations was not statistically significant. The same four predominant configurations constituted 80% of the SPVCs in each group. The vein of the cerebellopontine fissure was most frequently found in 86% and 88% of cases, and a petrosal–galenic anastomosis was seen in 38% and 40% of groups 1 and 2, respectively. Conclusions: Individual SPVC variations are extensive. Good quality bFFE or equivalents are feasible for preoperative SPVC assessments. However, methods improving vascular visualization are recommended. [ABSTRACT FROM AUTHOR]

Intraparenchymal meningiomas without dural attachments are extremely rare. A 32-year-old female adult was admitted to our hospital, complaining of occasional dizziness. The patient had no neurological deficits. MRI demonstrated a lesion with mild edema located in the left cerebellar parenchyma. CT revealed calcification within the mass. Gross total resection was achieved. The histopathological examination indicated that the lesion was an atypical meningioma (WHO-II). We herein report an extremely rare case of an intraparenchymal meningioma located in the left cerebellar hemisphere. The significance of the differential diagnosis of lesions in the cerebellum should be emphasized. [ABSTRACT FROM AUTHOR]

Single stereotactic radiosurgery (SRS) for posterior fossa brain metastases (BM) larger than 4cm3 is dangerous. 'Sandwich treatment' strategy was developed for these BMs. The strategy was one week treatment course which includes 2-stage SRS and using Bevacizumab once during SRS gap. Patients from four gamma knife center were retrospectively analyzed. The changes of tumor and peri-tumor edema volume were studied. The Dizziness Handicap Inventory (DHI) Vomiting Score (VS) and Glasgow Coma Scale (GCS) were used to evaluate patients' clinical symptom changes. Karnofsky performance scale (KPS) and Barthel Index (BI) were used to evaluate patients' overall fitness status and physical activity rehabilitation. Tumor local control (TLC) and patients' overall survival (OS) rate were also calculated. Forty patients with 45 LBMs received 'Sandwich treatment'. The mean edema volume reduced remarkably at the course of therapy and 3 months later (P < 0.01). The mean tumor volume greatly decreased 3 months later (P < 0.01). Patients' clinical symptoms that reflected by median score of DHI, VS, GCS were improved dramatically at the course of therapy and 3 months later (P < 0.01). Similar changes happened in median score of KPS and BI that reflected patients' overall fitness status and physical activity rehabilitation (P < 0.01). Patients' median OS was 14.3 months, with 95.4%, 76.2%, and 26.3% survival rate at 6, 12, 24 months. The TLC rate at 6, 12, 24 months was 97.5%, 86.0% and 62.2%.The 'Sandwich treatment' is safe and effective for patients with LBM over 4cm3 in the posterior fossa. The strategy could quickly improve patients' symptoms, well control tumor growth, prolong patient's OS, and has controllable side effects. [ABSTRACT FROM AUTHOR]

Copyright of Revista Argentina de Anatomia Online is the property of Asociacion Argentina de Anatomia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Postoperative pediatric cerebellar mutism syndrome (POPCMS) is a significant complication observed after posterior fossa surgery for tumors, particularly in pediatric neurosurgery. This paper presents a literature review on the physiopathology, diagnosis, treatment, and long-term outcomes of POPCMS. Methods: A systematic review following PRISMA guidelines, searching for articles published in PubMed, Web of Science, and Lilacs in the last ten years. Inclusion criteria involved studies on human subjects under 18 years of age, focusing on the pathophysiology, diagnosis, treatment, and outcome of POPCMS. Results: The review identified 34 studies on POPCMS for final inclusion. Preoperative risk factors commonly associated with cerebellar mutism included midline tumor location, diagnosis of medulloblastoma, younger age at diagnosis, preoperative language impairment, brainstem infiltration, and tumor histology. The SHH subgroup was found to reduce the risk of CMS. Diagnostic criteria for POPCMS included language impairment, emotional lability, hypotonia, oropharyngeal dysfunction, dysphagia, cerebellar motor syndrome, cerebellar cognitive affective syndrome, and brainstem dysfunction. Treatment approaches varied, with medications showing potential benefits. Rehabilitation options for speech and language deficits were limited. Cognitive remediation programs showed promise in improving academic achievement and attention. A significant proportion of patients experienced clinical improvement. Conclusion: POPCMS remains a challenging complication following posterior fossa surgery. Further research is needed to develop standardized diagnostic criteria, effective treatments, and rehabilitation strategies to improve long-term outcomes for patients with POPCMS. [ABSTRACT FROM AUTHOR]

Background: Infratentorial choroid plexus tumors are rare lesions in the pediatric population. At diagnosis, they most often present with signs of intracranial hypertension and cranial nerve deficits. The main objective of the surgery is total resection and the prognosis is favorable in most cases. Case Report: A 16-year-old boy with gait disturbance, headaches and left side hypoacusia had a diagnosis of posterior fossa tumor with hypertensive hydrocephalus. He underwent urgent placement of a ventriculoperitoneal shunt and subsequently microsurgery with gross total resection. At follow up, the patient was asymptomatic and without deficits. Conclusion: Choroid plexus tumors should be included in the differential diagnosis of posterior fossa tumors in childhood. Preoperative planning, choosing the best surgical approach and interruption of the lesion's vascular supply as the initial step of surgery are fundamental strategies for successful treatment. [ABSTRACT FROM AUTHOR]

Background Penetrating brain injury (PBI) can be caused by several objects ranging from knives to chopsticks. However, an assault with hand drill while working in a factory is a peculiar accident. Because of its rarity and lack of standard protocol management, the management of PBI is complex. Case Presentation We presented a case of a 26-year-old male with alleged history of insertion of eight nails from a hand drill machine from right side of head while working in a factory accompanied by loss of consciousness and history of vomiting. Computer tomography demonstrated that nails passed through the right parietal bone and reached up to contralateral hemisphere and posterior cranial fossa. Removal of nails and hematoma evacuation was done timely that led the patient to have a good postoperative recovery. Conclusion In this case report, we discussed the successful management of a very rare penetrating head injury with a hand drill machine. The goal of this case report is to demonstrate the general management principles in PBI that can improve the patient outcome. [ABSTRACT FROM AUTHOR]

We report on a patient, who underwent the resection of a cerebellar primary central nervous system lymphoma and was administered intraoperative fluorescein sodium to improve the visualization of the tumor and guide surgery. Low-dosage fluorescein was administered prior to opening the dura so to distinguish contrast-enhanced lymphomatous tissue from the surrounding unenhanced brain cerebellar parenchyma. Intraoperatively, the tumor was indistinguishable from cerebellar parenchyma under the white light, however, after the administration of low-dose intravenous fluorescein, it appeared brightly fluorescent under yellow light, and was safely resected. Our protocol of administration allowed for the sampling of the pathological tissue while at the same time avoiding neurological damage. The fluorescein-guided technique for the resection of primary central nervous system lymphomas has only been rarely described, as surgical excision of such tumors is rarely indicated. Starting from our case, we review and discuss the pertinent literature. Furthermore, an intraoperative video detail is provided. [ABSTRACT FROM AUTHOR]

Intracranial dermoid cysts are rare dysembryonic tumors of benign nature. These are uncommon in adults. If present, they are usually located in the midline or along the lines of embryonic fusion. The posterior fossa region is an infrequent site. Extradural or interdural locations are even more rare. In this case report, the authors report a laterally located large posterior fossa right cerebellar convexity interdural and extradural dermoid cyst over the sigmoid sinus. It was managed by totally extradural maximum possible safe decompression with microneurosurgical technique. The authors share their experience of addressing this rare pathology at the rarest location with unusual imaging findings. [ABSTRACT FROM AUTHOR]

Proliferating trichilemmal tumors (PTT) are rare benign lesions that predominantly occur in elderly women and usually affect the scalp. They originate from the outer root sheath of hair shafts and have trichilemmal differentiation on histopathological examination. Compared to trichilemmal cysts, PTTs show increased cell proliferation and variable cytological atypia. We report the first case of a patient with an intracranial PTT in the posterior fossa. The clinicoradiological presentation and surgical management of the patient as well as the possible pathogenesis of this tumor are discussed. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to verify the feasibility, safety, and benefit of using fluorescein sodium (FL) and a YELLOW 560 nm filter in posterior fossa tumors in children. Methods: All cases of pediatric posterior fossa tumors that have undergone surgery using fluorescein (2018–2022) have been included and were examined retrospectively. In those cases where resection of the tumor was planned, a blinded neuroradiologist distinguished gross total resection and subtotal resection according to the postoperative MRI findings. The surgical report and medical files were reviewed regarding the intraoperative staining grade and adverse events. The grade of fluorescent staining of the targeted lesion was assessed as described in the surgical reports. The screening was conducted for any reference to the degree of fluorescent staining: "intense," "medium," "slight," and "no staining." Results: 19 cases have been included. In 14 cases, a complete resection was initially intended. In 11 of these cases, a gross total resection could be achieved (78.6%). Staining was described as intense in most cases (58.8%). Except for yellow-colored urine, no side effects obviously related to FL were found throughout the observation period. Conclusion: In combination with a specific filter, FL is a reliable, safe, and feasible tool in posterior fossa surgery in children. [ABSTRACT FROM AUTHOR]

Background: Chronic supratentorial subdural hematoma is uncommon in neonates but accounts for most neurosurgical procedures in neonatal age. However, its occurrence in the posterior fossa is extremely rare. It can be caused by instrumental delivery, coagulation abnormality, hypoxic insult, and various structural abnormalities. Furthermore, spontaneous onset has been reported only in a few case reports. Case Presentation: A twenty-nine-day-old male neonate presented with failure to suck for three days duration associated with vomiting. Imaging showed bilateral posterior fossa chronic subdural hematoma and obstructive hydrocephalus. Bilateral burrhole craniostomy and hematoma evacuation was done which resulted in an excellent outcome. Conclusion: Posterior fossa chronic subdural hematoma is extremely rare in the neonatal period. It can be caused by various possible etiologic agents; however, rarely it can occur spontaneously. Management with suboccipital burrhole craniostomy and hematoma evacuation can result in a good outcome. Intraoperative monitoring and management with an experienced anesthesiology team are indispensable for a good outcome. Study Setting: Pediatrics neurosurgery ward, St Peter's Comprehensive Specialized Hospital, Addis Ababa, Ethiopia. [ABSTRACT FROM AUTHOR]

Background: Diencephalic-Mesencephalic Junction Dysplasia (DMJD) is a rare and recently newly described forebrain-midbrain malformation involving the upper aspect of the brainstem and resulting in an abnormal regionalization of the diencephalon and mesencephalon level. The fingerprint of DMJD is the pathognomonic butterfly-like appearance of the midbrain seen on the axial plane of brain magnetic resonance imaging (MRI). Initially, only two types of diencephalon-mesencephalon continuity were defined: type A describes the continuity of the hypothalamus with the mesencephalon, and type B a parenchymal band between the thalamus and the superior surface of the midbrain. However, DMJD classification continues to expand, and recently, type C was described as showing a complete continuity of the thalamus and midbrain. In this paper, we refer to mesencephalon and midbrain as the anatomical marker of the topmost part of the brainstem, and those terms are used interchangeably in the text. Methodology: PubMed database search for the exact words "diencephalic-mesencephalic junction dysplasia" and "DMJD" yielded 12 relevant publications. A showcase of an original rare type C DMJD was performed. Objective: The purpose of this article is to present a brief comprehensive illustration/ elucidation of the physiopathology of neural tube regionalization to facilitate the understanding of DMJD malformation; to present an updated overview of recent publications involving imaging findings, genetics, and clinical concerns; and to show an original fetal case of type C DJMD. The aim is to increase awareness of DMJD and strengthen clinical suspicion, especially since early diagnosis is primarily based on imaging. [ABSTRACT FROM AUTHOR]

Pseudomeningocele formation following posterior fossa surgery is a well-recognised complication, occurring in up to 33% of operated cases in some series. Ossification of a cranial pseudomeningocele is, however, an exceptionally rare event with only three prior reported cases. We present the unique case of a paediatric patient who developed rapid ossification of a giant occipital pseudomeningocele following posterior fossa surgery. An 8-year-old female patient underwent a midline posterior fossa craniotomy for resection of an exophytic brainstem low-grade glioma. Post-surgery, the patient developed pan-ventricular hydrocephalus and a large occipital pseudomeningocele, which initially increased in size despite a successful endoscopic third ventriculostomy (ETV) being performed. At approximately 3 months post-surgery, reduction of the pseudomeningocele was observed with associated prominent ossification of the pseudomeningocele wall on computed tomography (CT) imaging. Surgical excision was subsequently undertaken, and intra-operatively, a large ossified pseudomeningocele was found. Follow-up MRI 1 month later demonstrated almost complete resolution of the pseudomeningocele with an associated reduction in the degree of pan-ventricular ventriculomegaly. This case highlights that ossification of even giant pseudomeningoceles can occur over a time period of just a few months and clinicians should consider ossification whenever a change in size or consistency of a post-operative pseudomeningocele is encountered. [ABSTRACT FROM AUTHOR]

Posterior fossa atypical teratoid rhabdoid tumor (ATRT) is a rare childhood tumor usually associated with a dismal prognosis. Although upfront surgical gross total resection (GTR) has classically been the first line of treatment, new multimodal treatments, including two-stage surgery, are showing promising results in terms of overall survival (OS) and complication rate. We present a case of a 9-month-old child treated with two-staged surgery and chemotherapy. When deemed risky, multimodal treatments, including staged surgeries, can be a safe alternative to reduce surgical mortality and morbidity. At 23 months old, the patient had normal global development and no major impact on quality of life. We, therefore, discuss the most recent advancements from a treatment perspective, including molecular targeting. [ABSTRACT FROM AUTHOR]

Purpose: The transpetrosal–transtentorial approach provides a practical and safe surgical corridor for the treatment of petroclival region lesions. Any inaccuracies while performing this surgical technique can result in catastrophic results; nevertheless, this can be prevented under the guidance of a detailed anatomical orientation. An "intertriangles line" was defined to preserve the internal auditory canal (IAC) and cochlea during extradural bone drilling. Methods: The anatomical study consisted of two groups: the cadaveric head and the skull group. A literature-based landmark and criteria list was created to examine the borders of the Kawase triangle/space and evaluate the anatomical structures that may be at risk during drilling for anterior petrosectomy. Results: A total of 20 cadaveric head sides and 30 dried skull sides were examined. The rhomboid area was divided into two triangles with a common the intertriangles line. In all dissections, the IAC was found to be localized posterior to the "intertriangle line". A minimum distance of 1 mm for the Internal Carotid artery and 2 mm for the IAC can serve as threshold values to be considered by the surgeon during drilling for petrosectomy. Conclusions: Kawase's area resembles a minefield, in which every step and manipulation should be considered. A minimal but effective resection of the cranial base is needed to increase safety and decrease morbidity during skull base surgery. Furthermore, this study investigated accessible and prominent landmarks to establish a feasible area of triangles and define the intertriangles line to guide the neurosurgeon under microscope and avoid IAC injury. [ABSTRACT FROM AUTHOR]

Copyright of Ümraniye Pediatri Dergisi is the property of KARE Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: To determine whether intraoperative adjunctive EVD placement in patients with a posterior fossa tumor (PFT) led to improved surgical, radiographic, and clinical outcomes compared to those who did not receive an EVD. Methods: Patients were grouped as those who underwent routine intraoperative adjunctive EVD insertion and those who did not at time of PFT resection. Patients who pre-operatively required a clinically indicated EVD insertion were excluded. Comparative analyses between both groups were conducted to evaluate clinical, radiological, and pathological outcomes. Odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were computed for post-operative outcomes. Results: Fifty-five selected patients were included, 15 who had an EVD placed at the time of PFT resection surgery, and 40 who did not. Children without an EVD did not experience a higher rate of complications or poorer post-operative outcomes compared to those with an EVD placed during resection surgery. There was no significant difference in the degree of gross total resection (p = 0.129), post-operative CSF leak (p = 1.000), and post-operative hemorrhage (p = 0.554) between those with an EVD and those without. The frequency of new cranial nerve deficits post-operatively was higher in those with an EVD (40%) compared to those without (3%, p = 0.001). There was a trend towards more frequently observed post-operative hydrocephalus in the EVD group (p = 0.057). Conclusion: The routine use of EVD as an intraoperative adjunct in clinically stable pediatric patients with posterior fossa tumors and hydrocephalus may not be associated with improved radiological or clinical outcomes. [ABSTRACT FROM AUTHOR]

Background: Results of the management of superior cerebellar artery (SCA) aneurysms are typically reported in combination with those for all posterior circulation aneurysms. We report our experience with the management of SCA aneurysms and a systematic review of the endovascular management of these rare aneurysms. Methods: Patients with saccular SCA aneurysms that were not associated with arteriovenous malformations and who presented to our institute between 2000 and 2017 were identified. Patient demographics, aneurysm characteristics, interventions, and follow-up data were collected, compared, and analyzed. For the review, data including number of aneurysm treated, outcomes, follow-up, and occlusion rates were collected. Results: Mean age of the 31 identified patients was 57.4 ± 12.3 years; 19.4% were men. Mean aneurysm size was 5.1 ± 2.9 mm. Seven of 21 patients with unruptured aneurysms were managed conservatively. Ten patients (32.3%) presented with ruptured aneurysms (mean aneurysm size, 6.2 ± 3.2 mm). Treatment was successfully completed in 22 patients: 13-primary coiling, 7-stent-assisted coiling, and 2-microsurgical clipping. Complete angiographic aneurysm occlusion after primary treatments was achieved in 19 (86.4%) patients. The total complication rate among treated patients was 4.2% (1 of 24 treated aneurysms). No minor complications occurred. However, in 2 patients, coil embolization was attempted but aborted due to coil protrusion into the parent artery. Clinical and angiographic follow-up data were available for 26 observed or treated patients. Mean follow-up duration was 5.3 ± 4.5 years. Six articles met our review inclusion criteria and demonstrated similar mean treated aneurysm sizes ranging from 4.6–7.7 mm, and follow-up from these articles ranged from 15.3–50 months. Conclusions: Endovascularly treated patients with ruptured and unruptured SCA aneurysms, of which most were <7 mm, had good clinical outcomes with minimal complications. [ABSTRACT FROM AUTHOR]

Introduction: Ependymomas (EPN) are the third most common malignant brain cancer in children. Treatment strategies for pediatric EPN have remained unchanged over recent decades, with 10-year survival rates stagnating at just 67% for children aged 0-14 years. Moreover, a proportion of patients who survive treatment often suffer long-term neurological side effects as a result of therapy. It is evident that there is a need for safer, more effective treatments for pediatric EPN patients. There are ten distinct subgroups of EPN, each with their own molecular and prognostic features. To identify and facilitate the testing of new treatments for EPN, in vivo laboratory models representative of the diverse molecular subtypes are required. Here, we describe the establishment of a patient-derived orthotopic xenograft (PDOX) model of posterior fossa A (PFA) EPN, derived from a metastatic cranial lesion. Methods: Patient and PDOX tumors were analyzed using immunohistochemistry, DNA methylation profiling, whole genome sequencing (WGS) and RNA sequencing. Results: Both patient and PDOX tumors classified as PFA EPN by methylation profiling, and shared similar histological features consistent with this molecular subgroup. RNA sequencing revealed that gene expression patterns were maintained across the primary and metastatic tumors, as well as the PDOX. Copy number profiling revealed gains of chromosomes 7, 8 and 19, and loss of chromosomes 2q and 6q in the PDOX and matched patient tumor. No clinically significant single nucleotide variants were identified, consistent with the low mutation rates observed in PFA EPN. Overexpression of EZHIP RNA and protein, a common feature of PFA EPN, was also observed. Despite the aggressive nature of the tumor in the patient, this PDOX was unable to be maintained past two passages in vivo. Discussion: Others who have successfully developed PDOX models report some of the lowest success rates for EPN compared to other pediatric brain cancer types attempted, with loss of tumorigenicity not uncommon, highlighting the challenges of propagating these tumors in the laboratory. Here, we discuss our collective experiences with PFA EPN PDOX model generation and propose potential approaches to improve future success in establishing preclinical EPN models. [ABSTRACT FROM AUTHOR]

Background: Prenatal diagnoses of cystic malformations of the posterior fossa mainly encompass arachnoid cysts, Blake's pouch cysts and Dandy-Walker syndrome. To date, vermian cysts have not been reported prenatally. Objectives: To report a series of fetuses with a vermian cyst. Materials and methods: This was a single-center retrospective study conducted from 2012 to 2021. We included all fetuses presenting with a vermian cyst and excluded all other types of posterior fossa cyst. The cyst was visible at prenatal ultrasound (US) and/or magnetic resonance imaging (MRI). Postnatal imaging and/or clinical outcome data were available. Results: Sixteen fetuses fulfilled the inclusion criteria with a strong female predominance (n=13). US and MRI were performed at a mean gestational age of 29+5 and 33+1 weeks, respectively. In all patients, the cyst was in the vermian horizontal fissure. The mean longest dimension was about 10 mm. The vermis and other posterior fossa structures were otherwise normal. At postnatal imaging, 13 children underwent brain imaging including 11 MRIs with complete regression (n=9), stability (n=1) and increase in size (n=3) of the cyst. Psychomotor development was normal in 14 children. One child (with an inner ear malformation) showed a slight delay in walking and language acquisition. Slight walking ataxia was present in another child. Conclusion: We report 16 fetuses with posterior fossa cysts located within the vermis at the level of the horizontal fissure, diagnosed at US and/or MRI and carrying an overall excellent neurological prognosis. [ABSTRACT FROM AUTHOR]