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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]

The rhomboid lip is a neural tissue encountered during cerebellopontine angle surgery, with differing shape and extent among individuals. This study aimed to investigate the variation of rhomboid lips during posterior fossa surgery. In this retrospective study, we examined posterior cranial fossa surgeries performed using a retrosigmoid approach. Rhomboid lips were classified according to thickness, extent, and appearance, with some subjected to histological analysis. T2-weighted magnetic resonance imaging of rhomboid lips was conducted. Among 304 surgeries, rhomboid lips were observed in 75 patients who underwent schwannoma or meningioma resection, facial spasm-related neurovascular decompression, and other surgeries (37, 2, 32, and 4 patients, respectively). Rhomboid lips were categorized based on apparent thickness: thin membranous type, resembling an arachnoid membrane, and thick parenchymal type. Rhomboid lip extension was classified by position relative to the choroid plexus: nonextension, lateral extension, and jugular foramen (41, 22, and 12 patients, respectively). Veins were observed on the rhomboid lip surface in 37 cases. The rhomboid lip was visible in only 1 case (parenchymal jugular foramen type) on magnetic resonance imaging. Histologically, the rhomboid lip comprised an ependymal cell layer, a glial layer, and connecting tissue. The glial layer thickness determined the rhomboid lip thickness, which was greater in the parenchymal type than in the membrane type. In 42 patients, the rhomboid lip was dissected with no complications observed. Morphological classification of the rhomboid lip and understanding of its anatomical details contribute to safe surgical field development for neurosurgeons. [ABSTRACT FROM AUTHOR]

Chiari I malformation (CM-I) is defined as the extension of brain tissue into the spinal cord. This study aimed to refine the methodology for the acquisition of 3-dimensional measurements of the posterior fossa and introduce occipital keel size as a new marker and its impact in patients with CM. In this retrospective study, all patients who underwent Chiari decompression surgery at Montefiore Medical Center from April 2012 to April 2022 were included. Perioperative clinical information was obtained in addition to maximal keel thickness (KT), foramen magnum area, and preoperative and postoperative posterior fossa volumes for each patient and age-matched controls. Volumetric measurements were obtained using artificial intelligence-based semiautomated segmentation. A total of 107 patients with CM including 37 males, and 70 females were studied with a mean age of 26.56 ± 17.31 compared with 103 controls without CM. The comparison between the CM and the general population groups demonstrated a significantly increased keel size in Chiari patients. Keel size had a significant relationship with dysphagia, paresthesia, and intraoperative blood loss, while posterior volume change had a significant relationship with sex and early symptomatic improvement. The Foramen magnum area was related to tonsillar descent and more prominent in patients with spina bifida. The Keel of Goodrich is a new anatomical factor that should be taken into consideration when evaluating preoperative symptoms, and intraoperative complications in patients with CM-I. Volumetric analyses demonstrated that posterior fossa volume change had a significant impact on early symptom improvement in patients with Chiari, as did the choice of operative approach. The routine use of semiautomated segmentation of the posterior fossa may help stratify Chiari patients in the future and should be implemented in routine clinical care. [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.

Cerebellar liponeurocytoma is a rare WHO grade II glioneuronal tumor, characterized by a benign course and a more favorable prognosis. In this paper, we report a 52-year-old man, hospitalized in emergency because of clinical signs of increased intracranial pressure, and gait disturbances. The MRI revealed a lateral well shaped solid lesion within the left cerebellar hemisphere, having a low signal intensity compared to the cerebrospinal fluid, and causing a triventicular hydrocephalus and tonsillar herniation. The patient underwent a direct approach of the tumor through a left suboccipital craniectomy. Total removal of the lesion was achieved, and the histological diagnosis was cerebellar liponeurocytoma. The tumor cell proliferation index was < 6 %, therefore, radiotherapy and chemotherapy were not implemented after surgery. After 5 years of close follow-up there were no clinical or radiological signs of recurrence.Our objective in reporting another case of this unusual tumor is to discuss clinical profile, radiologic and histologic features as well as treatment and prognosis of this rare posterior fossa tumor.

Yufeng Liu,1,&ast; Jie Liu,1,&ast; Xiaoyan Wu,1 Enshe Jiang2,3 1Department of Cardiovascular Medicine, Luoyang Central Hospital affiliated to Zhengzhou University, Luoyang, Henan, 471000, People’s Republic of China; 2Department of Neurosurgery, The First Affiliated Hospital of Henan University, Kaifeng, Henan, 475004, People’s Republic of China; 3Institute of Nursing and Health, Henan University, Kaifeng, Henan, 475004, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Enshe Jiang, Email esjiang@gmail.comAbstract: 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.Keywords: surgery duration, posterior fossa, cerebrospinal fluid leakage, drainage tube, antibiotics, glucocorticoids

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]

A cerebellar bulge prior to posterior fossa resection is an emergency condition during surgery. Intraoperative cerebellar bulging not only increases the difficulty of lesion resection but also brings additional postoperative complications. Currently, there are few systematic reports on this topic. The predictors of cerebellar bulge and how to effectively prevent intraoperative cerebellar bulge are discussed in this article. The clinical and imaging data of 527 patients with posterior fossa lesions who underwent resection at our hospital were retrospectively collected and analyzed. Perioperative clinical and imaging data were assessed. Variables were analyzed using univariate and multivariate regression analyses. Overall, 10.4% (55/527) of patients had intraoperative acute bulges. Multivariate analysis revealed that age <60 years, body mass index ≥24, lesion size ≥30 (mm), cerebellar tonsillar herniation and/or hydrocephalus, and perilesional edema (moderate-severe) were predictors of cerebellar bulging. Relief of the cerebellar bulge can be accomplished by excising the lesion, releasing cerebrospinal fluid, and removing the cerebellum (the outer one-third). Obvious cerebellar-related complications occurred in 4 patients postoperatively, and the symptoms disappeared after 6 months of follow-up. Cerebellar bulging during intraoperative posterior fossa resection deserves attention. Through the analysis of multiple factors related to cerebellar bulge, comprehensive evaluation and early intervention during the perioperative period are necessary. The incidence of cerebellar bulges can be reduced, and surgical complications related to cerebellar bulges can be avoided. [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]

Venous sinus thromboses (VSTs) are rare complications of neurosurgical procedures in the proximity of the dural sinuses. Surgery of the posterior cranial fossa (PCF) and particularly of the cerebellopontine angle (CPA) shows increased risk of VST. VST management is challenging because anticoagulant therapy must be balanced with the risk of postoperative bleeding. We performed a systematic review and meta-analysis to summarize the most important neuroradiologic and clinical aspects of VST after PCF/CPA surgery. We performed a comprehensive literature search to identify articles reporting data on VST after PCF/CPA surgery. We selected only comparative studies providing adequate neuroimaging assessing VST and a control group. We included 13 articles reporting 1855 patients. VST occurred in 251/1855 cases (estimated incidence, 17.3%; 95% confidence interval [CI], 12.4%–22.2%). Only presigmoid approach (odds ratio [OR], 2.505; 95% CI, 1.161–5.404; P = 0.019) and intraoperative sinus injury (OR, 8.95; 95% CI, 3.43–23.34; P < 0.001) showed a significant association with VST. VST-related symptoms were reported in 12/251 patients with VST (pooled incidence, 3.1%; 95% CI, 1%–5.2%). In particular, we found a significantly increased OR of cerebrospinal fluid leak (OR, 3.197; 95% CI, 1.899–5.382; P < 0.001) and cerebrospinal fluid dynamic alterations in general (OR, 3.625; 95% CI, 2.370–5.543; P < 0.001). Indications for VST treatment were heterogeneous: 58/251 patients underwent antithrombotics, with 6 treatment-related bleedings. Recanalization overall occurred in 56.4% (95% CI, 40.6%–72.2%), with no significant difference between treated and untreated patients. However, untreated patients had a favorable outcome. VST is a relatively frequent complication after PCF/CPA surgery and a presigmoid approach and intraoperative sinus injury represent the most significant risk factors. However, the clinical course is generally benign, with no advantage of antithrombotic therapy. [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]

Ganglioglioma is a rare neoplasm most common in children and adolescents. It is typically located in the supratentorial compartment, with the temporal lobe being the most common tumor location. Anaplastic ganglioglioma is a WHO grade III ganglioglioma, a rare subtype accounting for a small minority of ganglioglioma cases. Posterior fossa anaplastic ganglioglioma in an adult is incredibly rare; only 3 prior cases have been reported. Only 1 adult anaplastic ganglioglioma in the cerebellum has been reported. We present the second reported adult cerebellar anaplastic ganglioglioma.

Microcystic meningioma is an uncommon subtype of World Health Organization grade 1 meningiomas often associated with a shorter progression-free survival. Diagnosis through imaging alone can often be challenging due to atypical characteristics, especially when found in unexpected locations. Here, we present a 55-year-old woman who was diagnosed, based on imaging, with a posterior fossa arachnoid cyst 5 years prior after complaints of headaches and gait imbalance. After surgical resection of the “arachnoid cyst,” the diagnosis of microcystic meningioma was made. This case report emphasizes the clinical importance and challenges associated with diagnosing microcystic meningiomas.

AbstractAlthough glioblastoma is the commonest primary brain tumour in adults, its location in the cerebellum is extremely rare. We present thirteen cases (3 female, 10 male; median age at presentation 56 [age range 21–77]) of surgically managed, histologically confirmed, primary cerebellar glioblastoma (cGB) over a 17 year period (2005–2022). Pre-operative radiological diagnosis was challenging given cGB rarity, although MRI demonstrated ring enhancement in all cases. Surgical management included posterior fossa craniectomy and debulking in 11 cases and burr hole biopsy in two. CSF diversion was necessary in four cases. No evidence of IDH or ATRX gene mutations was found when tested. Survival ranged from 1 to 22 months after diagnosis (mean 10.9 months). We also seek to understand why glioblastoma is rare in this location and discuss potential reasons for this. We hypothesise that increasing anatomical distance from germinal regions and decreased local endogenous neural stem cell activity (which has been associated with glioblastoma) may explain why glioblastoma is rare in the cerebellum. We hereby seek to add to the limited literature on cGB as this is the largest UK cGB series to date. [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: 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]

Durotomies, traditionally used during the midline suboccipital approach, involve sacrificing the occipital sinus (OS) with consequent shrinking of the dura, risk of venous complications, difficulty performing watertight closure, and a higher rate of postoperative cerebrospinal fluid (CSF) leaks. The present technical note describes the OS-sparing linear paramedian dural incision, which leads to a decrease in the risk of complications during the median suboccipital approach in our case series. The OS-sparing linear incision technique involves a dural incision placed 1 cm lateral to the OS. The angle of view of the microscope is frequently changed to overcome the narrowed exposure of the linear durotomy. Copious irrigation with saline prevents drying of the dura. A running watertight closure of the dura is performed. The overall results of 5 cases are reviewed. The cases were 3 tumors and 2 cavernomas. The OS was preserved in all 5, and no duraplasty was needed. The average dura closure time was 16.8 minutes. No CSF leak occurred, and no wound complications were observed. A gross total resection of the lesion was achieved in all the patients. The mean follow-up was 10.2 months, and there were no late complications related to the dura closure. In comparison to the types of durotomies conventionally used for the midline suboccipital approach, the OS-sparing linear paramedian dural incision entails lower risks of bleeding, venous complications, CSF leaks, and infections by avoiding duraplasty. Validation of this technical note on a larger patient cohort is needed. [ABSTRACT FROM AUTHOR]

Introduction and objective: The main causes of vertigo in childhood are benign and have a favorable prognosis, the most prevalent being recurrent vertigo of childhood and vestibular migraine [1]. Less frequent are the central causes of vertigo, but most of them are associated with serious and lifethreatening disorders, hence the importance of making an early diagnosis and thus being able to start a specific treatment for each pathology. Method: A narrative review of the literature in the Pubmed, Dialnet and SciELO databases of articles published on causes of central vertigo in childhood in the last 15 years has been carried out. Conclusions: The structural core causes of vertigo in childhood are varied and rare. They are characterized by associating the vestibular clinic with other central neurological symptoms and headache. the seriousness of some of them, it is necessary to make an early diagnosis through imaging tests, mainly MRI, and start a specific treatment as soon as possible. [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]

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]

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]

The burden of tuberculosis is very high in our country and though the number of deaths due to tuberculosis has drastically reduced, still the associated morbidities caused by the disease can be very debilitating.1 Central nervous system tuberculosis is a rare and serious presentation of tuberculosis, the general presentation being hydrocephalus, meningitis, and disseminated miliary lesions.2 More often than not tuberculosis is associated with immunocompromised status and central nervous system tuberculosis in immunocompetent young individuals with no evidence of systemic tuberculosis is very rare.3Association of tuberculosis with ocular manifestations and even blindness is not uncommon, the causes of blindness being causes like uveitis, retinitis, interstitial keratitis, ophthalmitis, and even orbital tuberculosis.4 Classical teaching in neurosurgery is that a posterior fossa lesion unless proven otherwise is a metastasis. Therefore, here we are discussing three cases of central nervous system tuberculosis in isolation, without any systemic involvement in immunocompetent adults in the posterior fossa region as well as a literature review of cases from across the globe of posterior fossa tuberculosis in immunocompetent adults. The first case is regarding a treatable cause like tuberculoma in an immunocompetent young adult causing blindness which is rare as well as unfortunate. The other two cases highlight the need to keep tuberculosis as a differential even when the clinical features, radiological features, and blood and other investigations are not suggestive.

Summary: Background: Traumatic brain injuries involving the posterior fossa are rare and case reports indicate they often result in severe outcomes. We seek to describe characteristics and outcomes of traumatic posterior fossa injuries. Methods: We performed a planned secondary analysis of all patients with posterior fossa injuries enrolled in the NEXUS head computed tomography (CT) validation study dataset. The dataset includes prospectively collected data on all patients undergoing non-contrast cranial CT following blunt traumatic head injury from April 2006 to December 2015, at four emergency departments comprising community and university sites, as well as urban, suburban and rural settings in California (Antelope Valley Hospital, San Francisco General Hospital, UCLA Ronald Reagan Medical Center, UCSF Fresno Community Regional Medical Center). We classified each patient into one of three injury patterns: Type I—notable traumatic injuries primarily above the tentorium, with minimal posterior fossa involvement; Type II—notable traumatic injuries both above and within the posterior fossa; and Type III—notable traumatic injuries primarily within the posterior fossa. We extracted demographic data for each patient as well as physician assessments of the NEXUS head CT and Canadian Head CT rule clinical criteria, mechanisms of injury, patient outcomes, and the location and types of intracranial injuries sustained. Findings: Of 11,770 patients in the database, 184 (1.6%) had posterior fossa injuries on CT imaging. Mean age was 55.4 years (standard deviation 22.5 years, range 2–96 years); 131 (71.2%) were males. We identified 63 patients with Type I injuries, 87 with Type II injuries, and 34 Type III injuries. The most common mechanisms of injury were falls (41%), pedestrian vs automobile (15%), and motor vehicle collisions (13%). On presentation most patients had altered mental status (72%), abnormal behavior (53%), or a neurologic deficit (55%). The majority of individuals, 151 (82%), had clinically important injuries and 111 (60%) required neurosurgical intervention. The dispositions for the subjects included 52 deaths (28%), 49 (27%) patients discharged home, and 48 (26%) discharged to rehabilitation facilities. When compared to individuals with Type I and Type II injuries, patients with Type III injuries had lower mortality (6% vs 30% and 35%) and higher percentage of patients discharged home (60% vs 19% and 21%). Interpretation: Patients with Type I and II injury patterns (those that involve both the posterior fossa and supratentorium) experienced high mortality and disability. Patients with Type III injuries (isolated posterior fossa) had a better prognosis. Funding: None.

Approaching posterior fossa pathologies is fairly challenging. Poor exposure, Cerebrospinal Fluid (CSF) leak following surgery, post-operative suboccipital and neck pain, and wound healing are common challenges following traditional suboccipital midline incision. Herein, we present a new incision for approaching posterior fossa pathologies. The incision is shaped like a question mark and makes a musculofascial flap supplied by occipital artery on top of providing a wide area for craniotomy. In our technique, the dura is also incised in a question mark shaped manner. Three patients with masses in posterior fossa were operated with the new incision. Following surgeries, there were no adverse events including CSF leak, wound complications, severe suboccipital pain and neck instability in any of the patients. This new incision not only facilitates approaching to pathologies in posterior fossa with providing wider exposure, but also enables us for watertight Dural closure which decreases CSF leak. Also, as the muscular incision provides a sufficient area for craniotomy, muscular retraction can be minimized to avoid post-operative pain. Moreover, as opposed to the midline avascular incision, the flap is well supplied by occipital artery which facilitates the healing procedure.

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. [Med-Science 2023; 12(4.000): 1066-73]

The role of surgical management of arachnoid cyst (AC) of the cerebellopontine angle (CPA) is uncertain. This topic has remained controversial with varying contradictory recommendations in the literature, which is limited to mostly case reports. We aimed to provide a comprehensive summary and analysis of symptoms, operative techniques, outcomes, and recurrence of all available surgical cases of AC of the CPA to date. A systematic literature search was performed in May 2022 querying several scientific databases. Inclusion criteria specified all studies and case reports of patients with AC located at the CPA for which any relevant surgical procedures were performed. A total of 55 patients from the literature and 5 treated at our institution were included. Mean patient age was 29 years (range, 0.08–79 years), with nearly twice (1.7×) as many female as male patients (37 female, 22 male). Headaches (35%), hearing loss (30%), vertigo (22%), and ataxia (22%) were the most common presentations. Following surgery, 95% experienced symptom improvement, with complete resolution in 64%. Of patients with hearing loss, 44% reported a return to normal. The rate of mortality was 1.69%, and 10% of tumors recurred (mean follow-up 2.3 years [range, 0–15 years]. Symptomatic AC of the CPA is rare. It exhibits a proclivity for females and commonly manifests with headache, hearing loss, vertigo, and ataxia. While careful selection for surgical candidacy is needed and intervention should be reserved for patients with severe symptoms, surgical decompression is an effective tool for symptom alleviation and recovery. [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]

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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]

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]

The distal suboccipital segment of the occipital artery is commonly used as a donor vessel for aneurysms of the posterior circulation requiring revascularization techniques. Isolating this segment of vessel can be challenging due to its course in and out of the various layers of the suboccipital musculature. We describe the use of the proximal suboccipital segment of the occipital artery within the occipital groove at the lateral skull base as a donor segment for an interposition graft in revascularization surgery. We present a case detailing the use of this technique for treatment of a dissecting PICA aneurysm and photographs from cadaveric dissections demonstrating relevant anatomy. Our patient is a 62-year-old man who presented with a high-grade subarachnoid hemorrhage from a proximal dissecting-type aneurysm of the posterior inferior cerebellar artery (PICA). Endovascular options were limited to coil sacrifice of the parent vessel, and thus the patient was taken for a far lateral craniotomy, trapping of the aneurysm, and revascularization of the PICA territory via a saphenous vein interposition graft sewn proximally and distally to the occipital artery within the occipital groove and a cortical segment of the affected PICA, respectively. Postoperative imaging demonstrated filling of the PICA territory via the graft, and the patient ultimately recovered from his subarachnoid hemorrhage. The use of the proximal suboccipital segment of the occipital artery is a viable option for a donor in posterior fossa revascularization surgery. [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]

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]

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]

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]

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: Brain tumour is a common problem in paediatric age group and posterior fossa is the commonest location. Treatment of these tumours is difficult due to a confined space and potential involvement of brainstem. The aim of this study is to analyse the clinical features, radiological findings, pathological diagnosis, surgical management, postoperative complications and outcome in 3 months in paediatric patients with posterior fossa tumours. Method: Retrospective chart review of 24 patients treated in the Department of Neurosurgery, TUTH, between 2019 April – 2023 April was done. The variables included were age, sex, clinical features, radiological findings, histopathological diagnosis, management and postoperative complications. Results: Twenty-four patients (30%) out of 80 childhood tumors were located in posterior fossa. The most common presenting symptoms was headache in 83.3% and vomiting in 75%. The most common location of tumour was the fourth ventricle in 66.7% while most common tumour histology was Type IV medulloblastoma in 45%. The commonest mode of treatment in 90% of cases was Ventriculoperitoneal (VP) shunting followed by surgical excision of tumour. Conclusion: Posterior fossa tumours are common tumour occurring in children. Majority of the patients presented with features of raised intracranial pressure and gait ataxia. Fourth ventricle and cerebellar vermis are the most common location. Most common histology types are medulloblastoma followed by pilocytic astrocytoma and ependymoma. Management involves addressing acute hydrocephalus followed by definitive surgery. Keywords: Medulloblastoma, Paediatrics, Posterior fossa, Surgery, Ventriculoperitoneal shunt

Intradiploic epidermoid cysts are rare intracranial tumours, with an estimated prevalence of less than 1% of all cranial tumours. Most of the intradiploic cysts are asymptomatic; however, clinical findings consist of headache and tenderness. We presented a case of a 21-year-old female who consulted the neurosurgery department for a period of three years about a mass in the occipital region, which was growing gradually. The patient was treated with surgical removal without complications. Intradiploic epidermoid cysts are infrequent intracranial tumours that primarily affect adults. This tumour has a wide spectrum of symptoms. Radiologic findings on computed tomography (CT) and magnetic resonance imaging (MR) are the cornerstone for the diagnosis, which is finally confirmed by histopathological studies. Surgical management with a complete resection of the cyst and capsule is the most commonly used treatment.

Eyerusalem Bergene,1 Abdi Ermolo Tira,2 Endris Hussen,1 Caitlyn J Smith,3 Yonas T Fetle4 1Department of Neurosurgery, St. Paul’s Millennium Medical College, Addis Ababa, Ethiopia; 2Department of Neurosurgery, St. Peter’s Comprehensive Specialized Hospital, Addis Ababa, Ethiopia; 3Department of Neurosurgery, University of Missouri School of Medicine, Columbia, MO, USA; 4Department of Neurosurgery, Addis Ababa University College of Health Science, Addis Ababa, EthiopiaCorrespondence: Eyerusalem Bergene, Email monorovia@gmail.comBackground: 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.Keywords: posterior fossa, chronic, subdural hematoma, neonate

Aim: Posterior cranial fossa (PCF) surgery is associated with complications, including cerebrospinal fluid (CSF) leakage. Dural sealants such as polyethylene glycol (PEG)-based hydrogels and fibrin glue can prevent CSF leaks, with evidence suggesting PEG hydrogels may outperform fibrin glue. However, the budget impact of using PEG hydrogels in PCF surgeries in Europe is unclear. Materials & methods: A decision tree was developed based on a previous US model, to assess the budget impact of switching from fibrin glue to PEG hydrogel in PCF surgery across five European countries. Input costs were derived from published sources for the financial year 2022/2023. Health outcomes, including CSF leaks, were considered. Results: The model predicted that using PEG hydrogel instead of fibrin glue in PCF surgery can lead to cost savings in five European countries. Cost savings per patient ranged from EUR 419 to EUR 1279, depending on the country. Sensitivity analysis showed that the incidence of CSF leaks and pseudomeningoceles had a substantial impact on the model’s results. Conclusion: PEG hydrogels may be a cost-effective alternative to fibrin glue in PCF surgery. The model predicted that cost savings would be mainly driven by a reduction in the incidence of postoperative CSF leaks, resulting in reduced reliance on lumbar drains, reparative surgery and shortened hospital stays.

Introduction: Studies report rates of treatment-requiring postoperative intracranial haemorrhage after craniotomy around 1–2%, but do not distinguish between supratentorial and posterior fossa operations. Reports about intracranial haemorrhages’ temporal occurrence show conflicting results. Recommendations for duration of postoperative monitoring vary. Research question: To determine the rate, temporal pattern and clinical presentation of reoperation-requiring postoperative intracranial posterior fossa haemorrhage. Material and methods: This retrospective case-series identified cases operated with posterior fossa craniotomy or craniectomy between January 1, 2007 and December 31, 2021 by an electronic search in the patient administrative database, and collected data about patient- and treatment-characteristics, postoperative monitoring, and the occurrence of haemorrhagic and other serious postoperative complications. Results: We included 62 (n = 34, 55% women) cases with mean age 48 (interquartile range 50) years operated for tumours (n = 34, 55%), Chiari malformations (n = 18, 29%), ischemic stroke (n = 6, 10%) and other lesions (n = 3, 5%). One (2%) 66-year-old woman who was a daily smoker operated with decompressive craniectomy and infarct resection, developed a reoperation-requiring postoperative intracranial haemorrhage after 25.5 h. In four (6%) cases, other serious complications requiring reoperation or transfer from the post anaesthesia care unit or regular bed wards to the intensive care unit occurred after 0.5, 6, 9 and 54 h, respectively. Discussion and conclusion: Treatment-requiring postoperative intracranial haemorrhage and other serious complications after posterior fossa craniotomies occur over a wide timespan and are difficult to capture with a standardized postoperative monitoring time. This indicates that the duration of monitoring should be individualized based on assessment of risk factors.

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.