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Objective To investigate the imaging diagnosis and differential diagnosis methods for common tumors in the posterior fossa of children, and to propose a flow chart for the diagnosis of common tumors in the posterior fossa of children based on the limited diffusion of DWI according to the idea of localization diagnosis followed by qualitative diagnosis. Methods A total of 118 pediatric patients with posterior fossa tumors who underwent surgical resection in Huashan Hospital, Fudan University from January 2021 to January 2024 were enrolled, and all of them underwent head CT and MRI examinations, and preoperative localization diagnosis and qualitative diagnosis were carried out accordingly. Then, based on whether DWI was diffusion limited, a flow chart for the diagnosis of common tumors in the posterior fossa of children was proposed. Results A total of 118 children with posterior fossa tumors were localization and qualitatively diagnosed, including 41 cases of fourth ventricular tumors, including medulloblastoma (27 cases), pilocytic astrocytoma (7 cases), ependymoma (5 cases), choroid plexus papilloma (one case), and rosette-forming glioneuronal tumor (RGNT, one case). There were 38 cases of brainstem tumors, including 24 cases of diffuse midline glioma, H3 K27 - altered, 5 cases of pilocytic astrocytoma, 3 cases of cavernous hemangioma, 2 cases of pediatric-type diffuse high-grade glioma (prone to diffuse midline glioma, H3 wild type), 2 cases of ganglio glioma, one case of atypical teratoid/rhabdoid tumor (AT/RT), and one case of pediatric - type diffuse low - grade glioma. There were 9 cases of cerebellopontine angle (CPA) tumors, including 3 cases of pilocytic astrocytoma, 2 cases of cholesteatoma, one case of medulloblastoma, one case of diffuse midline glioma, H3 K27-altered, one case of pilomyxoid astrocytoma, and one case of Ewing sarcoma. There were 30 cases of cerebellar tumors, including 15 cases of pilocytic astrocytoma, 7 cases of medulloblastoma, 2 cases of cavernous hemangioma, one case of ependymoma, one case of pediatric-type diffuse low-grade glioma, one case of pediatric-type diffuse high- grade glioma (prone to diffuse midline glioma, H3 wild type), one case of dysembryoplastic neuroepithelial tumor (DNT), one case of hamartoma, and one case of extrarenal rhabdomyomatoid tumor cerebellar metastases. Localization diagnosis, the accuracy of preoperative CT was 93.22% (110/118), while the accuracy of preoperative MRI was 100% (118/118). Qualitative diagnosis, 74 cases (62.71%) had accurate qualitative diagnosis, 23 cases (19.49%) had general diagnosis, and 21 cases (17.80%) had wrong diagnosis. The imaging differential diagnosis of posterior fossa tumors in children focuses on medulloblastoma, pilocytic astrocytoma, ependymoma, and diffuse midline glioma, H3 K27-altered. The incidence of limited diffusion of DWI in medulloblastoma, pilocytic astrocytoma and ependymoma outside the brainstem was 100% (35/35), 4% (1/25) and 5/6, and the difference among the three tumors was statistically significant (Z = - 5.601, P = 0.000). The incidence of limited diffusion of DWI in diffuse midline glioma, H3 K27- altered and pilocytic astrocytoma in the brainstem was 79.17% (19/24) and 1/5, and the difference between the two tumors was also statistically significant (Fisher's exact possibility: P = 0.038). Conclusions The early diagnosis of posterior fossa tumors in children is difficult, and DWI is an important basis for differential diagnosis.

Cerebellar mutism syndrome (CMS) is a prevalent postoperative complication in children following posterior fossa tumor surgery, with a significantly variable incidence rate across different pathological types of tumors, being highest in medulloblastoma (24%-30%). The pathogenesis of CMS remains to be elucidated, but it is believed to be associated with damage to the cerebellocerebral circuits, harm to the fastigial nuclei of cerebellum and periaqueductal gray matter of the midbrain, and alterations in brain networks. Predictive models constructed based on the risk factors of CMS have not yet demonstrated the anticipated stability and have not been widely adopted in clinical settings. Pharmacological treatments are primarily based on clinical experience, yet their efficacy requires further validation, hence there is currently a lack of a clearly effective treatment method; non-pharmacological treatments, such as physical therapy, occupational therapy, and speech therapy, have shown some effect on improving the long - term quality of life. This review summarizes the pathogenesis and therapeutic advances of CMS, and future research should be dedicated to exploring the pathophysiological mechanisms of CMS, constructing more accurate predictive models, devising personalized treatment plans, and enhancing the long-term prognosis for children.

In contrast to tumors in children, between 6% and 20% of all brain tumors in adults arise solitary in the posterior cranial fossa. Given their rarity in adults, as well as the importance and complexity of their treatment, this paper reviews and discusses the clinical and surgical characteristics of such tumors. In a retrospective single-institution observational study, adult patients with posterior fossa tumors treated surgically over a ten-year period were analyzed. The characteristics observed were age and gender distribution, clinical symptoms, histopathologic tumor type, tumor size, location and extent of surgical resection, tumor recurrence and postoperative complications, as well as surgical outcome. Sixty-six patients who underwent surgical treatment were diagnosed with a tumor in the posterior fossa. The mean age was 63 years, and patients were evenly distributed by gender. The most common histopathologic type was metastatic tumor (59.1%), whereas meningioma was the most common primary brain tumor (16.6%) recorded. Most patients presented with vegetative and cerebellar symptoms in general and cranial nerve palsy, especially in the occurrence of vestibular schwannoma. In conclusion, posterior fossa tumors grow in a confined space and therefore may directly threaten vital centers in their immediate vicinity. Thus, it is crucial to schedule an appropriate surgical intervention as soon as possible, as it can significantly improve treatment outcome and prognosis of the disease. If possible, meticulous total tumor resection should be the treatment of choice. In the case of hydrocephalus, a ventriculoperitoneal shunt should be considered as an alternative surgical option after tumor resection.

Background: Malignant swelling is a fatal complication that can occur abruptly in space-occupying cerebellar infarction. We aimed to establish markers that predict malignant swelling in cerebellar infarction., Methods: We retrospectively analysed data of stroke patients who were treated in our hospital between 2014 and 2020. Malignant swelling was defined as a mass effect in the posterior cranial fossa, accompanied by a decrease in consciousness due to compression of the brainstem and/or the development of obstructive hydrocephalus. Statistical analyses were performed on multiple variables to identify predictors of malignant swelling., Results: Among 7284 stroke patients, we identified 487 patients with an infarct in the cerebellum. 93 patients were suitable for analysis having space-occupying cerebellar infarction. 33 of 93 (35.5%) patients developed malignant swelling. Multivariable analysis revealed infarct volume as the main predictor being independently associated with the development of malignant swelling with a cut-off infarct volume of 38 cm 3 being associated with a swelling rate of >50% (OR 32.0, p<0.001). Higher NIHSS (National Institutes of Health Stroke Scale) score on admission (median NIHSS 12 vs 4, OR 1.078; p=0.008) and the presence of additional brainstem infarction (51.5% vs 16.7%, OR 5.312; p=0.013) were associated with the development of malignant swelling in univariate analyses. 13 of 33 (39.4%) cases of malignant swellings occurred after more than 3 days., Conclusions: Infarct volume was the key significant predictor of malignant swelling in space-occupying cerebellar infarction. With many cases of malignant swelling occurring after more than 72 hours, we advocate prolonged neurological monitoring., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background Deep ⁃ seated clival varied malignancies represent a surgical challenge because of complex anatomy and surgical procedures posing great risks to adjacent neurovascular structures. To investigate effects of diagnosis and treatment of clival region lesions, review experience of individualized surgical procedures and comprehensive therapy. Methods and Results A total of 56 patients with clival malignancies from July 2007 to December 2018 were included. The patients mainly presented with headache and cranial nerve paresis. After multidisciplinary consultation, radical resection were performed in 45 cases different kinds of surgical approaches including endonasal (15 cases, 33.33% ), intraoral accompanied by intraoral and endonasal combined (7 cases, 15.56%), Derome (8 cases, 17.78%), maxillary swing (9 cases, 20% ), and infratemporal (6 cases, 13.33% ) approaches were chosen according to clinical and radiographic findings, and biopsies were performed in 11 patients to confirm the pathological diagnosis. The primary pathological finding was chordoma (28 cases, 50%). Total resection was achieved in 21 cases (46.67%), and 17 cases (37.78%) underwent subtotal resection. Besides, partial resection was performed in 7 cases (15.56% ). The complications developed in 28 patients, including cranial nerve deficits (13 cases, 23.21%), cerebrospinal fluid leakage (14 cases, 25%), intracranial infection (8 cases, 14.29%), pneumonitis (2 cases, 3.57% ), postoperative hematoma (2 cases, 3.57% ), and mental disorder (1 cases, 1.79% ). Adjuvant chemoradiotherapy was provided by the oncologists depending on the pathological findings. The average follow⁃up was 59.90 months, but 8 patients (14.29%) were lost. The progression⁃free survival was achieved in 16 patients (28.57%), whereas the disease progression occurred in 13 patients (23.21%). The mortality was 33.93% (19/56). Conclusions Although malignancies occupy a larger subset of clival tumors, not all are needed to be radically resected. Our preliminary results suggest that multidisciplinary consultation is indispensable to clarify the therapeutic purpose and provide individualized surgical approaches. Postoperative comprehensive therapy may reduce the surgical complications and improve the outcomes of patients. DOI：10.3969/j.issn.1672⁃6731.2020.03.008

Background: Approximately 20% of all transient ischaemic attacks (TIAs) and ischaemic strokes occur within the posterior circulation, with vertebrobasilar stenosis identified as the cause in roughly 25% of the cases. Studies have shown that about a quarter of these patients have atherosclerotic stenosis of at least 50% of the vertebrobasilar artery. Stenosis has been shown to be associated with an increased risk of 90-day recurrent vertebrobasilar stroke, particularly in the first few weeks, which is significantly higher when compared with patients with stenosis of the anterior circulation. Therefore, aggressive treatment is important for the patient's prognosis. Stenting is emerging as a promising therapeutic strategy for persistent ischaemia events that do not respond to the best medical treatment, but it is not without complications. We systematically reviewed the literature on percutaneous transluminal angioplasty and stenting (PTAS) for intracranial vertebrobasilar artery stenosis (IVBS)., Methods: PubMed, Web-of-Science and Scopus were searched upon the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to include prospective/retrospective cohort, randomised/non-randomised clinical trials and case series studies describing PTAS for IVBS. Pooled rates of intervention-related complications and outcomes were analysed with random-effect model meta-analysis using StataMP V.18.0 software., Results: 31 studies were found eligible which included 1928 cases. 1103 basilar artery stenosis cases were reported in 27 studies 0.65 (95% CI 0.53, 0.76), I 2 : 99.72%. 648 vertebral cases were reported in 18 studies 0.60 (95% CI 0.49, 0.70), I 2 : 97.49%. In four studies, the rate of vertebrobasilar stenosis cases calculated as a proportion of the total sample size was 0.10 (95% CI 0.05, 0. 15). Mean stenosis in 21 included studies was found to be 0.83 (95% CI 0.79, 0.88), I 2 : 0.00%, which shows variation of baseline stenosis between studies was minimal. 51 deaths were recorded in 24 studies. Meta-analysis of mortality showed the overall rate of mortality was 0.03 (95% CI 0.02, 0.05), I 2 : 44.90%. In 14 studies, symptomatic intracranial haemorrhage events were recorded at an overall rate of 0.01 (95% CI 0.00, 0.02), I 2 : 0.00%. Generally, a follow-up period of at least 3 months was reported in the included studies. Furthermore, procedural stroke/TIA was evaluated in seven studies, four of which reported no events (0.03 (95% CI 0.00, 0.08), I 2 : 20.38%). Mean time from initial symptoms to recanalisation was 23.98 (95% CI 18.56, 29.40), I 2 =98.8%, p=0.00 days., Conclusion: In certain individuals with medically unresolved, severe, symptomatic and non-acute IVBS, elective vertebrobasilar PTAS appears to be both safe and effective. Various stent designs and angioplasty-assisted techniques should be taken into consideration based on the specific clinical and radiological traits of the lesions. Future randomised controlled trials are required to verify these results., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Basilar invagination (BI) is a common deformity. This study aimed to quantitatively evaluate the height of clivus and atlanto-occipital lateral mass (LM) in patients with BI with or without atlas occipitalization (AOZ). We evaluated 166 images of patients with BI and of controls. Seventy-one participants were control subjects (group A), 68 had BI with AOZ (group B), and 27 had BI without AOZ (group C). Parameters were defined and measured for comparisons across the groups. Multiple linear regression analysis was used to test the relationship between Chamberlain's line violation (CLV) and the clivus height ratio or atlanto-occipital LM height. Based on the degree of AOZ, the lateral masses in group B were classified as follows: segmentation, incomplete AOZ, complete AOZ. From groups A to C, there was a decreasing trend in the clivus height and clivus height ratio. There was a linear negative correlation between the clivus height ratio and CLV in the three groups. Generally, the atlanto-occipital LM height followed the order of group B < group C < group A. The atlanto-occipital LM height was included only in the equations of groups B. There were no cases of atlantoaxial dislocation (AAD) in group C. There was a decreasing trend in LM height from the segmentation type to the complete AOZ type in group B. BI can be divided into three categories: AOZ causes LM height loss; Clivus height loss; Both clivus and LM height loss. The clivus height ratio was found to play a decisive role in both controls and BI group, while the atlanto-occipital LM height loss caused by AOZ could be a secondary factor in patients with BI and AOZ. AOZ may be a necessary factor for AAD in patients with congenital BI. The degree of AOZ is associated with LM height in group B., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Posterior fossa tumors are common in the pediatric population and require adequate characterization by means of structural magnetic resonance imaging (MRI) and advanced MRI techniques to achieve an appropriate therapeutic approach. Objectives: To determine the usefulness of apparent diffusion coefficient (ADC) values for the differential diagnosis of posterior fossa tumors in the pediatric population treated at a reference hospital in Bogotá D.C., Colombia. Materials and methods: Diagnostic accuracy study carried out in 28 pediatric patients diagnosed with posterior fossa tumor between 2017 and 2019 at the Fundación Hospital de la Misericordia, a quaternary care institution. ADC values were measured and compared with histopathological diagnosis as gold standard, obtaining sensitivity, specificity, and positive and negative predictive values. Differences between medians were determined using the Kruskall-Wallis test. The p value between the quantitative ADC value and the gold standard was calculated using Pearson's chi-squared test, with a significance level of p

The vertebral arteries represent in the adult the main blood supply of the posterior cranial fossa, even if they appear relatively late during the embryological life. We reviewed all the most important steps of the vertebral artery's embryological development and the most common variants that can occur in the adult. The aim of this review is to summarize the main events of the development of this artery and to give an embryological explication for the most common variants of this artery., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Background: Postoperative pediatric cerebellar mutism syndrome (CMS) may occur following a process affecting the posterior cranial fossa. Recent evidence demonstrates disabling and potentially lasting motor components of this syndrome, including ataxia, hemiparesis, and oculomotor dysfunction. These impairments may contribute to vestibular deficits., Methods: This case series contributes data to quantify vestibular dysfunction in postoperative CMS. The pair consisted of one female and one male., Results: Vestibular testing demonstrated both peripheral and central dysfunction., Conclusions: Given these findings, a thorough vestibular assessment may be indicated as part of a comprehensive evaluation following a postoperative CMS diagnosis. Further research is needed to understand the pathophysiology, treatment, and long-term outcomes of postoperative pediatric CMS., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Osteoradionecrosis (ORN) of the skull base is a rare complication after head and neck radiation with a broad variety of subsequent complications., Methods: A 68-year-old woman with a complex oncological history (right-sided sphenoid meningioma; left-sided neck metastasis of a Cancer of Unknown Primary-CUP) was admitted with a right-sided epi-/ oropharyngeal mass and severe pain exacerbations for further evaluation. CT scan revealed an advanced ORN of the skull base with subsequent abruption of the ventral part of the clivus. This dislocated part of the clivus wedged in the oropharynx for 48 h and then moved towards the larynx, resulting in dyspnea and almost complete airway obstruction., Results: Due to the dangerous airway situation, an urgent exploration and removal of the dislocated clivus was necessary. After a potential cervical spine instability was ruled out, the patient's airway was initially secured with an awake tracheotomy and the clivus was removed transorally. The tracheostomy tube was removed during the ongoing inpatient stay, and the patient was discharged with significant pain relief., Conclusions: The present case illustrates an orphan complication of skull base ORN resulting in a major airway emergency situation., (© 2024. The Author(s).)

Competing Interests: The authors have no funding or conflicts of interest to disclose.

Objective To compare the three-dimensional anatomic differences of far lateral approach versus presigmoidal approach to expose inferior clivus by virtual reality technique. Methods CT and MRI image data of 15 cadaver heads (30 sides) were inputted into Vitrea virtual reality system to establish three-dimensional anatomy model of posterior cranial fossa. Three points including anterior edges of bilateral tubercula jugulare and tubercula pharyngeum were selected to form a plane. The region of inferior clivus was defined as area under the aforementioned plane. The anterior edge of intersection curve between the plane and the clivus was selected as skull base landmark to expose. The mastoidale and posterior edge of occipital condyle articular surface were selected as craniotomy landmarks of presigmoidal and far lateral approaches. Cylinder with 1 cm diameter was outlined to simulate surgical approach, of which the axis passed through the aforementioned craniotomy landmarks. The superior edge of bottom surface of cylinder on the side of skull base was located in the aforementioned landmark of skull base. Anatomic exposures of the above two approaches were compared by paired t test. Results The far lateral approach located at the lateral edge of foramen magnum, anterior to the cerebellum, lateral to the brain stem, medial to the jugular bulb, lateral and inferior to the accessory nerve, involved hypoglossal nerve and reached inferior clivus. Bone drilling through presigmoidal approach began with mastoidale. The approach passed through inferior edge of jugular bulb, anterior to the sigmoid sinus, inferior to the accessory nerve, involved hypoglossal nerve at the lateral edge of foramen magnum, reached inferior clivus anterior to the brain stem. The volumes of surgical route [(4629.80 ± 81.00) mm3 vs. (2622.60 ± 72.58) mm3; t = 91.532, P = 0.000] and route involving hypoglossal nerve [(10.15 ± 0.17) mm3 vs. (7.15 ± 0.20) mm3; t = 52.413, P = 0.000] through presigmoidal approach were more than those through far lateral approach. Osseous structures involved in far lateral approach was more than that in presigmoidal approach [(2362.90 ± 80.18) mm3 vs. (1851.60 ± 63.62) mm3; t = 25.714, P = 0.000]. Conclusions Passing through hypoglossal nerve and drilling partial osseous structures will help to avoid cerebellum and brain stem and expose inferior clivus through far lateral approach and presigmoidal approach. DOI: 10.3969/j.issn.1672-6731.2017.12.008

Background: There are many morphometric studies on Chiari malformation type I (CMI) patients, most of which focus on the posterior cranial fossa (PCF). Less attention has been paid to the atlanto-occipital joint. In this study, we aim to evaluate the morphological characteristics of the atlanto-occipital joint in CMI patients., Materials and Methods: The cervical CT imaging data of adult patients diagnosed with CMI but without any bony malformation in craniovertebral junction (CVJ) who were treated by the authors between January 2014 and December 2019 were retrospectively analyzed. The equal number of sex and age-matched healthy individuals were included as the control group. The morphometric analysis was performed by measuring the length and depth of the atlanto-occipital joint, and the depth/length ratio was calculated to evaluate the curvature of the joint., Results: A total of 47 patients (15 males and 32 females) were included. The mean age of patients was 47.49 ± 9.01 years (range 19-62 years). The mean depth/length ratio of the atlanto-occipital joint in CMI patients was 0.141 ± 0.065 (range 0.027 - 0.274), which was smaller than that of control individuals (0.228 ± 0.057, range 0.069 - 0.379). And the difference was statistically significant ( p  < .01)., Conclusions: The atlanto-occipital joints in CMI patients are significantly flatter compared with those in healthy controls. This morphological variation could lead to differences of the atlanto-occipital stability between CMI patients and normal population, which may be related to the pathogenesis of CMI.

The diagnosis of Chiari I malformation is straightforward in patients with typical signs and symptoms of Chiari I malformation and magnetic resonance imaging (MRI) confirming ≥5 mm of cerebellar tonsillar ectopia, with or without a syrinx. However, in many cases, Chiari I malformation is discovered incidentally on MRI to evaluate global headache, cervical radiculopathy, or other conditions. In those cases, the clinician must consider if cerebellar tonsillar ectopia is related to the presenting symptoms. Surgical decompression of the cerebellar tonsils and foramen magnum in patients with symptomatic Chiari I malformation effectively relieves suboccipital headache, reduces syrinx distension, and arrests syringomyelia progression. Neurosurgeons must avoid operative treatments decompressing incidental tonsillar ectopia, not causing symptoms. Such procedures unnecessarily place patients at risk of operative complications and tissue injuries related to surgical exploration. This chapter reviews the typical signs and symptoms of Chiari I malformation and its variant, Chiari 0 malformation, which has <5 mm of cerebellar tonsillar ectopia and is often associated with syringomyelia. Chiari I and Chiari 0 malformations are associated with incomplete occipital bone development, reduced volume and height of the posterior fossa, tonsillar ectopia, and compression of the neural elements and cerebrospinal fluid (CSF) pathways at the foramen magnum. Linear, angular, cross-sectional area, and volume measurements of the posterior fossa, craniocervical junction, and upper cervical spine identify morphometric abnormalities in Chiari I and Chiari 0 malformation patients. Chiari 0 patients respond like Chiari I patients to foramen magnum decompression and should not be excluded from surgical treatment because their tonsillar ectopia is <5 mm. The authors recommend the adoption of diagnostic criteria for Chiari 0 malformation without syringomyelia. This chapter provides updated information and guidance to the physicians managing Chiari I and Chiari 0 malformation patients and neuroscientists interested in Chiari malformations., (© 2024. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

The treatment of pathologies located within and surrounding the orbit poses considerable surgical challenges, due to the intricate presence of critical neurovascular structures in such deep, confined spaces. Historically, transcranial and craniofacial approaches have been widely employed to deal with orbital pathologies. However, recent decades have witnessed the emergence of minimally invasive techniques aimed at reducing morbidity. Among these techniques are the endoscopic endonasal approach and the subsequently developed endoscopic transorbital approach (ETOA), encompassing both endonasal and transpalpebral approaches. These innovative methods not only facilitate the management of intraorbital lesions but also offer access to deep-seated lesions within the anterior, middle, and posterior cranial fossa via specific transorbital and endonasal corridors. Contemporary research indicates that ETOAs have demonstrated exceptional outcomes in terms of morbidity rates, cosmetic results, and complication rates. This study aims to provide a comprehensive description of endoscopic-assisted techniques that enable a 360° access to the orbit and its surrounding regions. The investigation will delve into indications, advantages, and limitations associated with different approaches, while also drawing comparisons between endoscopic approaches and traditional microsurgical transcranial approaches., (© 2024. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

Background: There is no comprehensive and up-to-date overview of audiovestibular approach to the posterior fossa tumors in the literature., Objective: This paper reviewed the literature relating to tumors at the posterior cranial fossa to find red flags alerting a posterior fossa lesion from audiovestibular perspectives., Methods: This review was developed from articles published in those journals listed on the journal citation reports. Through the PubMed database, Embase, Google Scholar, and Cochrane library, 60 articles were finally obtained based on the PRISMA guidelines for reporting reviews., Results: The presence of one red flag indicates a positive predictive value of 33% for detecting a posterior fossa lesion. Clinical features, namely, 1) mid-frequency sudden sensorineural hearing loss (SNHL), 2) bilateral sudden SNHL, and 3) rebound nystagmus may indicate a posterior fossa lesion, representing one, two, and three red flags, respectively., Conclusion: Those with 1) mid-frequency sudden SNHL, 2) bilateral sudden SNHL, and 3) rebound nystagmus trigger one, two, and three red flags, respectively, alerting clinicians the possibility of a posterior fossa lesion, which warrant MR imaging to exclude life-threatening or treatable conditions., Significance: Patients with posterior fossa tumors may have potential life-threatening outcome.

Background: Intra-osseous vessels are normal anatomic structures in the calvarium and skull base. On imaging, these structures-particularly venous lakes-can mimic pathologic abnormalities. This study sought to assess the prevalence of veins and lakes in the skull base on MRI., Materials and Methods: A retrospective review was completed of consecutive patients that underwent contrast-enhanced MRI imaging of the internal auditory canals. The clivus, jugular tubercles, and basio-occiput were assessed for the presence of both intra-osseous veins (serpentine and/or branching vessels) and venous lakes (well-circumscribed round or oval enhancing structures). Vessels in the adjacent synchondroses major foramina were excluded. Three board-certified neuroradiologists performed independent blinded reviews, with discrepancies agreed upon by consensus., Results: 96 patients were included in this cohort (58.3% female). Mean age was 58.4 years (range = 19-85). At least one intra-osseous vessel was identified in 71 (74.0%) patients. 67 (70.0%) had at least one skull base vein, and 14 (14.6%) had at least one venous lake. Both vessel subtypes were observed in 8.3% of patients. Vessels were more commonly observed in women, though this did not reach statistical threshold ( p = 0.56). Age was not associated with the presence of vessels (0.59) or vessel location ( p values ranged from 0.44-0.84)., Conclusions: Intra-osseous skull base veins and venous lakes are relatively common findings on MRI. Both vascular structures should be considered normal anatomy, and care should be taken to not confuse these for pathologic entities., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

With a distinctive shape and surrounding anatomical structures, the fourth ventricle is located in the posterior cranial fossa. There are various pathologies, either developmental or acquired, that can present as a characteristic deformity of the fourth ventricle. Therefore, this paper will cover the anatomy of the fourth ventricle and correlate this to the various pathologies. The aim of this review is to improve the ability of the readers to recognise the change in shape and configuration of the fourth ventricle, enabling early detection of pathologies., (Copyright © 2023. Published by Elsevier Ltd.)

Objective The article analyzed the curative effect of different surgical treatments for non-solid hemangioblastoma in posterior cranial fossa to explore reasonable operation method. Methods Clinical data of 61 patients with non-solid hemangioblastoma who underwent surgeries in Tianjin Huanhu Hospital during July 2007 and June 2014 were retrospectively analyzed. According to surgical approaches and the situation of foramen magnum and atlas, these patients were divided into 5 groups: midline approach opening foramen magnum and atlas (Group A), midline approach without opening foramen magnum and atlas (Group B), paramedian approach opening foramen magnum and atlas (Group C), paramedian approach without opening foramen magnum and atlas (Group D), retrosigmoid approach (Group E). By collecting clinical symptoms, imaging findings, surgical records and postoperative complications, the surgical results and occurrence of postoperative complications were summarized and reasonable operation method was discussed. Results Among 61 patients, total resection was achieved in 56 cases (91.80%), and partial resection was achieved in 5 cases (8.20% ). The postoperative remission rate of 43 cases with hydrocephalus was 79.07% (34/43). Intracranial infection was the most common postoperative complication, accounting for 22.95% (14/61). There was significant difference in occurrence rate of intracranial infection among 4 subgroups: opening or not opening the foramen magnum and atlas with or without restoring bone flap (Z = 16.269, P = 0.001). In the subgroup of not opening foramen magnum and atlas with restoring bone flap, the infection rate, which accounted for 6.90% (2/29), was the lowest. Conclusions The surgical treatment options for non-solid hemangioblastoma in posterior fossa should be done according to patients' condition, and performed by a professional group. If conditions allow, not to open the foramen magnum and atlas, as well as intraoperative restoring bone flap should be chosen as far as possible, so as to reduce the occurrence of postoperative complications. DOI: 10.3969/j.issn.1672-6731.2015.06.013

In contrast to tumors in children, between 6% and 20% of all brain tumors in adults arise solitary in the posterior cranial fossa. Given their rarity in adults, as well as the importance and complexity of their treatment, this paper reviews and discusses the clinical and surgical characteristics of such tumors. In a retrospective single-institution observational study, adult patients with posterior fossa tumors treated surgically over a ten-year period were analyzed. The characteristics observed were age and gender distribution, clinical symptoms, histopathologic tumor type, tumor size, location and extent of surgical resection, tumor recurrence and postoperative complications, as well as surgical outcome. Sixty-six patients who underwent surgical treatment were diagnosed with a tumor in the posterior fossa. The mean age was 63 years, and patients were evenly distributed by gender. The most common histopathologic type was metastatic tumor (59.1%), whereas meningioma was the most common primary brain tumor (16.6%) recorded. Most patients presented with vegetative and cerebellar symptoms in general and cranial nerve palsy, especially in the occurrence of vestibular schwannoma. In conclusion, posterior fossa tumors grow in a confined space and therefore may directly threaten vital centers in their immediate vicinity. Thus, it is crucial to schedule an appropriate surgical intervention as soon as possible, as it can significantly improve treatment outcome and prognosis of the disease. If possible, meticulous total tumor resection should be the treatment of choice. In the case of hydrocephalus, a ventriculoperitoneal shunt should be considered as an alternative surgical option after tumor resection., (Sestre Milosrdnice University Hospital.)