Automatic detection of the fetal brain midsagittal plane on MRI using a deep learning pipeline.

Dermoid cysts are congenital lesions that typically occur along the midline. They usually remain asymptomatic unless ruptured, causing meningitis, hydrocephalus, or cranial nerve deficits. This case presents an exceptionally rare scenario of bilateral, symmetric intradiploic dermoid cysts of the occipital bone, which initially manifested as sensorineural hearing loss (an unusual symptom). A 21-year-old woman presented with right-sided hearing loss. Imaging showed bilateral, symmetric intradiploic cystic lesions within the occipital bone. The right-sided lesion had ruptured into the posterior fossa, releasing lipid-rich contents over the cerebellum. A T1-hyperintense signal along the right vestibular aqueduct suggested the migration of debris into the inner ear. Both lesions were resected with maximal safe resection, targeting the ruptured component and preventing future complications. Histopathological analysis confirmed that both lesions were dermoid cysts. Although typically associated with chemical meningitis, dermoid cyst rupture may rarely present solely with sensorineural hearing loss when fatty debris migrates into the vestibular aqueduct. Bilateral, symmetric intradiploic occipital lesions are rare and may reflect developmental anomalies at paired ossification centers. Surgical removal of the antigenic source, even without acute complications, may prevent delayed sequelae. A tailored resection approach that preserves vital structures, including the transverse sinus, is safe and effective. https://thejns.org/doi/10.3171/CASE2691.

To evaluate progression-free survival (PFS), overall survival (OS), local control (LC), and radiotherapy-related toxicities in the treatment of adult intracranial ependymoma. A retrospective analysis was performed of WHO grade 2-3 adult intracranial ependymoma patients (≥ 18 years) treated with surgery alone or surgery and adjuvant radiotherapy between 2000 and 2024. Kaplan-Meier analyses were used to estimate PFS and OS. Acute and late treatment-related toxicities were characterized. Fifty-eight patients met the inclusion criteria. Median age was 39 years (interquartile range [IQR] 25-51), and median follow-up was 51 months (IQR 23-103). Overall, 76% were WHO grade 2, 74% had posterior fossa location, gross total resection was achieved in 60%, 88% received adjuvant local radiotherapy, and 5% received adjuvant chemotherapy. Five and 10-year PFS rates were 80% and 64%, respectively; 5 and 10-year OS rates were 92% and 85%, respectively. There were 13 (22%) recurrences: The location of first failure was local in nine, distant in two, and both local and distant in two. The 5-year LC rate was 82% (95% CI 67-90%), and the 10-year LC rate was 72% (95% CI 53-84%). The median time to local failure was 5.4 years. Ten (22%) patients experienced at least one grade ≥ 2 late treatment-related toxicity. One potential secondary glioma (grade 5) occurred after nine years. In adult patients with intracranial ependymomas, surgery alone or surgery followed by radiotherapy resulted in relatively favorable long-term PFS, OS, and LC. Recurrences and late toxicities remain a concern.

Lateral-type ependymomas, or cerebellopontine ependymomas, of the posterior fossa are rare tumors extending into the cerebellopontine angle, encasing important neurovascular structures, presenting as a particular surgical challenge. We performed a radical resection of lateral-type ependymoma in a 2-year-old patient with anamnesis of torticollis and vomiting. Resection of the tumor was preceded by insertion of external ventricular drainage. Optimal treatment improving prognosis requires achieving gross total resection of the tumor.

Lumbar Puncture in the 21st Century: an Imaging-Based Primer to Determine Procedural Safety.

Surgical approaches to the fourth ventricle involve the suboccipital surface of the cerebellum, where the inferior vermian vein (IVV) and inferior hemispheric vein (IHV) are often encountered and are at risk of injury. Iatrogenic injury to these veins could thereby lead to venous infarction and other postoperative complications; however, venous anatomy of these veins remains less well characterised. A retrospective bilateral analysis of contrast-enhanced MRI was conducted for 79 patients (n = 158 hemispheres) focusing on presence, termination and diameter of these veins. Additionally, the dominant patterns of this surface were documented. These factors were then compared on the basis of laterality and sex. The IVV had an overall presence of 88.6% with no bilateral absence noted. The prevalent termination of the IVV was the straight sinus (47.9%). A single IHV was the frequent configuration (65.2%), with a maximum of 3 IHVs per hemisphere. IHVs were further investigated based on their configuration as longitudinal and transverse veins. The prevalent drainage point of the IHV was the tentorial sinus (42.8%). The mean diameter for the IVV and IHV was 1.7 ± 0.5mm and 1.5 ± 0.4mm, respectively. The suboccipital surface exhibited a prevalent co-dominant pattern (58.9%), followed by IVV dominant (32.3%) and IHV dominant patterns (8.9%), respectively. These findings provide clinically relevant data that will assist in surgical planning and reduce risk of iatrogenic injury during posterior fossa approaches.

Abstract Background Brain tumor(BT) in children and adolescent and Young adults(AYA) show age-related heterogeneity, yet data on age-stratified incidence and multidisciplinary team (MDT)–based care from LMICs remain scarce. Material and Methods Single centre retrospective review of electronic medical records for demographic, clinico-pathologic, MDT care (neurosurgery, radiation and paediatric/medical oncology team participation at any point in time) and overall-survival (OS) data of patients aged <40 years with primary BTs between January 2014 - December 2024 from a tertiary referral centre in India. Results Among 641 patients, infants(<3 years) constituted 3%, children(3-14 years) 23%, and AYA (15-39 years)74%; predominantly from urban regions(87.2%) and male gender(68%). Median symptom duration prior to presentation was 30 days (range, 10days–5years). Medulloblastoma(47%) in infants and, gliomas(64%) in AYA were the most frequent diagnosis; 66% of all gliomas were high- grade likely due to referral bias. Tumor location varied by age: posterior fossa(children) vs, supratentorial(infants and AYA)(p = 0.02). Only 37%(243/641) underwent definitive treatment that did not vary by age. MDT care delivery remained inconsistent across different age groups 14% (p-value-0.001) with 17 % vs 0.4% in those seeking definitive treatment vs opinion (pvalue-0.001). However , medulloblastoma patients demonstrated highest utilization(37%, p = 0.006). The treated cohort had 2- and 5-year actuarial OS of 62% and 55%, respectively. On univariate analysis, diagnosis and tumor site influenced OS; however, only diagnosis remained significant on multivariate analysis (p = 0.001). Conclusion Our study reveals distinct age-stratified patterns of paediatric and AYA BTs presentation, low treatment uptake, urban bias, and substantial gaps in MDTcare highlighting critical opportunities to strengthen referral pathways, expand outreach to underserved rural populations, and institutionalize MDT workflows. This analysis resulted in establishment of paediatric/AYA neuro-oncology tumor board at our centre, representing a scalable model to improve equitable care and BT outcomes in LMIC setting.

Medulloblastoma, the most common malignant pediatric posterior fossa tumor, exhibits metabolic reprogramming and tumor immune microenvironment heterogeneity in non-WNT/non-SHH subgroups, yet the interplay between these features remains poorly defined. Revealing potential molecular features and hidden therapeutic target, we integrated the transcriptomic data of non-WNT/non-SHH medulloblastoma from GEO and EMBL-EBI databases. Through examination of the Grp3/4 transcriptional continuum, we identified PCK2 (a key gene in the TCA cycle with the highest correlation with continuum score). We validated PCK2 as a driver of proliferation, migration, invasion, glycolysis, and M2 macrophage polarization in MYC-amplified MB cells through short hairpin RNA knockdown experiments. Together, our findings establish metabolic-TIME crosstalk as a prognostic determinant and proffer PCK2 as a therapeutic target for aggressive MB subtypes, offering insights into metabolic subtyping and precision therapy strategies to improve clinical outcomes.

The retrosigmoid approach is a standard surgical route used for the treatment of various tumors and vascular lesions in the cerebellopontine angle. However, postoperative reconstruction of the surgical defect could remain challenging, particularly in cases requiring intraoperative extension. For this reason, a novel concept was developed to define the surgical approach and enable precise defect coverage using a patient-specific implant. This concept was designed to be patient-specific and realized through 3D printing. The developed 3D printed template-implant concept was designed to facilitate precise craniotomy. The template is used as a stencil and a surgical marker is applied to delineate the implant contours directly on the patient's skull. This outline subsequently serves as a guide for where to perform the craniotomy and defines its boundaries. The custom-fit implant replicates the template design and ensures complete coverage of the craniotomy defect, while allowing intraoperative adjustment if required. Preclinical testing was conducted on a 3D printed simulation model representing the posterior cranial fossa (surgical area). The novel concept was tested by nine senior and attending neurosurgeons from the University Hospital Leipzig. Bilateral craniotomies were performed using the template and subsequently closed with the implant. The fit of the implant was evaluated using CT scans. The time required for preparation, including craniotomy, as well as for post-procedure handling, including implant placement, was recorded. The average gap of the new concept was 2.11mm, which was significantly smaller than that of the current standard approach (5.52mm) and showed lower variability. The entire procedure, including craniotomy and implant placement, took an average of 13min and 20s. The novel template-implant concept for retrosigmoid approaches improves defect coverage and reduces gap sizes. Furthermore, it demonstrates the potential of 3D printed patient-specific implants for more precise and predictable surgical procedures, although further studies are required to validate efficiency and clinical safety.

Dandy-Walker malformation (DWM) is a condition characterized by a cyst in the posterior cranial fossa contiguous with the fourth ventricle, combined with complete or partial agenesis of the cerebellar vermis; and elevation of the cerebellar tentorium, torcular Herophili, and transverse sinuses. DWM has been linked to specific genetic variants, with pathogenic or likely pathogenic variants reported in FOXC1, ZIC1, and ZIC4. Variants in the TUBB2B and TUBB3 genes are associated with abnormalities in tubulin, leading to cerebellar hypoplasia. In our study, three patients diagnosed with DWM underwent whole-genome analysis using next-generation sequencing, and two were found to have heterozygous variants in the tubulinopathy-associated genes TUBB2B and TUBB3, respectively. These findings indicate that some cases previously diagnosed as DWM may fall under the spectrum of tubulinopathies associated with cerebellar hypoplasia.

Dural arteriovenous fistulas (DAVFs) represent a rare form of intracranial arteriovenous malformation, characterized by direct shunts between meningeal arteries and dural sinuses, dural veins, or cortical veins. DAVFs located in the foramen magnum (FM) region, including those involving the marginal sinus and condylar vein, exhibit complex arterial supply, diverse venous drainage patterns, and a range of clinical symptoms and associated risks. We present a case involving a 61-year-old male patient with a DAVF in the foramen magnum region, who clinically manifested limited abduction of the left eye and diminished visual acuity. Digital subtraction angiography (DSA) confirmed the presence of a DAVF in this region. Successful endovascular treatment, which included comprehensive cerebral angiography, was conducted under general anesthesia. Postembolization cerebral angiography demonstrated complete obliteration of the DAVF in the foramen magnum region, with no additional abnormalities observed. The patient experienced a favorable recovery and exhibited no subsequent neurological deficits. Diagnosing foramen magnum DAVFs is particularly challenging due to their nonspecific symptomatology, which frequently mimics more prevalent cervical or posterior cranial fossa disorders, potentially resulting in diagnostic delays or inaccuracies. This report aims to elucidate the clinical course, imaging findings, and therapeutic interventions in a patient with a foramen magnum DAVF, thereby offering valuable insights to enhance clinical suspicion, improve diagnostic accuracy, and facilitate timely management of this condition.

Case DiagnosisAn 11-year-old male with medulloblastoma underwent gross total resection of a posterior fossa tumor, complicated by post-operative pediatric cerebellar mutism syndrome (ppCMS), exhibiting mutism, emotional dysregulation, impaired volitional movement initiation, and ataxia.Case DescriptionWhile ppCMS's pathophysiology remains incompletely understood, prevailing hypotheses implicate cerebellothalamocortical dysregulation, functional diaschisis, and inhibitory-excitatory network imbalance. This case explores the use of lorazepam, a benzodiazepine that enhances GABA-A receptor activity, as a potential neuromodulator to facilitate recovery in ppCMS.SettingTertiary care children's hospital.Assessments/ResultsPharmacologic trials with bromocriptine, risperidone, and gabapentin yielded minimal benefit. However, administration of intranasal midazolam (5 mg) during radiation simulation resulted in transient resolution of mutism and improved initiation of movement. Based on this response, lorazepam (2 mg daily, 0.06 mg/kg) was initiated, leading to sustained improvements in speech, motor function, and therapy participation. Functional outcome assessments, including the WeeFIM, revealed a 40-unit gain within one week of lorazepam initiation compared to a 1-unit gain in the preceding week. Immediate regression was noted upon medication discontinuation and reintroduction resulted in subsequent recovery.Discussion/RelevanceThe differential response to benzodiazepines compared to other medications suggests potential for inhibitory-excitatory network imbalances. Future research should explore whether less sedating benzodiazepines, such as clobazam, or other GABAergic modulators could provide similar benefits without the cognitive side effects associated with lorazepam.ConclusionsThere is compelling evidence that benzodiazepine-mediated GABAergic modulation may facilitate CMS recovery by restoring cerebellothalamocortical network function. The observed improvements in motor initiation and speech fluency underscore the potential for pharmacologic neuromodulation as an adjunct to traditional rehabilitative therapies.An 11-year-old male with medulloblastoma underwent gross total resection of a posterior fossa tumor, complicated by ppCMS, exhibiting mutism, emotional dysregulation, impaired volitional movement initiation, and ataxia. Amid ongoing neurorehabilitation, a pharmacologic trial with lorazepam led to a reproducible improvement in speech and engagement. Though transient, the response suggested reversible disruption within functional circuits rather than fixed structural damage. This case report uncovers latent functional capacity in ppCMS, which can help distinguish ppCMS from other overlapping neurologic or psychiatric conditions throughout the course of rehabilitation.

The cerebellar tentorium, composed of 2 laminae of dura mater, is an essential structure that separates the posterior and middle cerebral fossae. As it has a dural sinus within its 2 laminae, it carries significant risk potential. Cranium shape may affect its morphological properties. The cephalic index (CI) can easily describe a ratio of the length and width of the cranium. People may have different CI values individually, or some populations have a typical cranium shape that gives a clue for the CI. The aim of the present study was to investigate the morphometric properties of the cerebellar tentorium related to CI groups. A total of 594 participants’ (304 women and 290 men) computed tomographic angiography image series were included in the presented study, retrospectively. We evaluated cerebellar tentorium’s morphometric properties, its length, and its angle according to the McRae line, and compared these measurements in relation to CI. All morphometric evaluations were completed using free licensed Horos Software v.3.3.6. According to our results, morphometric properties tended to be higher in men than in women. We also found morphometric differences in the cerebellar tentorium among the CI groups. However, our results demonstrated that age was not effective on the cerebellar tentorium’s morphometric organization. Cerebellar tentorium has a potential risk for injuries during posterior cranial fossa approaches. A number of studies aimed to evaluate patients’ position during surgical interventions. However, the morphometric properties of cerebellar tentorium were not considered during the evaluation of patients’ surgical position in previous studies. Though statistically significant, observed differences and correlations in tentorial morphometry were weak and likely of limited clinical utility. Findings contribute to anatomical reference data but may not be useful for inferring surgical guidance.

Managing large posterior fossa brain metastases (PFBMs) poses significant challenges. Although staged stereotactic radiosurgery (SRS) is an effective and minimally invasive alternative for large brain metastases, its clinical utility for large PFBMs has not yet been fully elucidated. The aim of this study was to evaluate the safety and efficacy of staged SRS in the treatment of large PFBMs. This retrospective analysis included patients who underwent upfront staged SRS for PFBMs measuring 4 mL or larger between 2010 and 2024 at a single tertiary cancer center. Patients who had received prior local treatment were excluded from the study. The radiosurgical protocol encompassed delivering 24-30 Gy in 2 fractions, with a time interval of 3-4 weeks between sessions. Outcome measures, including overall survival, local control of large PFBMs, and leptomeningeal metastasis (LM), were assessed using time-dependent analyses, considering competing events when appropriate. A consecutive cohort of 92 patients (49 male, median age 68 years) with 96 large PFBMs was included in the study. Primary cancers were small cell lung cancer, non-small cell lung cancer, and colorectal, breast, genitourinary, and upper digestive tract cancers in 11, 30, 24, 16, 7, and 4 patients, respectively. Eighty-two patients (89%) exhibited neurological symptoms, and the median volume of large PFBMs was 9.0 mL. At the time of the second session, the median PFBM volume had decreased by 49% to 4.6 mL. During the treatment interval, 2 patients underwent urgent craniotomies due to tumor bleeding and obstructive hydrocephalus. The 1- and 2-year overall survival rates following staged SRS were 51% and 30%, respectively (median 12.2 months). The 1- and 2-year local failure rates for large PFBMs were 17% and 23%, respectively. Rapid tumor response (defined as a 50% or greater volume reduction at the second session) was the sole factor associated with higher probability of local tumor control (HR 0.32, 95% CI 0.12-0.86; p = 0.024). The mean Karnofsky Performance Status (KPS) score improved from 71 at the first SRS session to 85 at the second; the first follow-up mean KPS score was 90 (p < 0.001). The 1- and 2-year LM rates remained low at 11% and 14%, respectively. These results suggest that staged SRS is a safe and less invasive treatment option for selected patients with PFBMs larger than 4 mL, achieving reasonable local control rates and low LMs rates in the long term.

A One-Finger-Width "Baklava Dough" Dural Thinning Technique in Dura-Preserving Posterior Fossa Decompression for Chiari Type I Malformation.

Endoscopic endonasal surgery (EES) offers a direct ventral corridor to the skull base, potentially enabling maximal resection of extensive cholesteatomas (epidermoid cysts) in the posterior cranial fossa and parasellar region. However, outcomes and complications specific to this approach require detailed analysis. A retrospective review was conducted on 34 patients who underwent EES for cholesteatomas of the posterior fossa and parasellar region at a single center from 2011 to 2025 year. Extent of resection (near-total > 95%, subtotal 90-95%), complications, and neurological outcomes were analyzed. Near-total resection was achieved in 65% of cases and subtotal in 35%. The most frequent complications were postoperative cerebrospinal fluid (CSF) leakage (23.5%) and meningitis (23.5%; 33.3% in patients with intradural extension). Rates were significantly higher than for other skull base tumors. Only visual symptoms showed consistent postoperative improvement. New or worsened cranial nerve deficits occurred in 12% of cases. Arrested hydrocephalus requiring shunting developed in 14.7% of patients. The endoscopic endonasal approach is one of the surgical options for patients with cholesteatomas involving the posterior cranial fossa and the chiasmatic-sellar region. However, it is associated with a notably higher risk of CSF leakage and meningitis compared to EES for other pathologies, attributable to the lesion's adhesive and inflammatory characteristics. Furthermore, significant recovery of preoperative neurological deficits (except visual) is uncommon. These findings underscore that indications for selecting this approach must be strictly justified, taking into account the risk of complications.

BackgroundSpontaneous cerebellar hemorrhage (sCH) is a severe condition, due to the limited space in the posterior fossa. The temporal dynamics of cerebral physiological variables such as intracranial pressure (ICP), pressure reactivity index (PRx), cerebral perfusion pressure (CPP), “optimal” CPP (CPPopt), and CPP deviation from CPPopt (ΔCPPopt) and associations with functional outcome remain insufficiently characterized in sCH.MethodsThis study retrospectively analyzed 94 adult sCH patients treated at the neurointensive care (NIC) unit in Uppsala University Hospital, Sweden, between 2008 and 2024, with collected high resolution monitoring data. The association between insult intensity-duration, temporal dynamics, and interactions with cerebrovascular autoregulation of the cerebral physiological variables with Glasgow Outcome Scale at discharge (GODS) were analyzed in outcome heatmaps. Formal statistical analyses between % of good monitoring time (%GMT) of the cerebral physiological variables within/outside certain thresholds were analyzed in relation to GODS.ResultsIn the exploratory analyses, ICP > 15 mmHg demonstrated a descriptive trend toward unfavorable outcome irrespective of duration, particularly the first two days post-injury. Still, the association lacked significance (p = 0.85). Sustained PRx elevations > 0.2 showed a descriptive trend toward worse outcome, with expanding vulnerability over time. However, this association was not significant (p = 0.26). CPP < 80 mmHg was associated with worse outcome, particularly if PRx was elevated. In addition, CPP < 60 mmHg was associated with worse outcome, while CPP > 80 mmHg was associated with favorable outcome (p = 0.02, respectively). Negative ΔCPPopt for longer durations and if PRx was elevated correlated with lower GODS. ΔCPPopt < -5 mmHg was associated with worse outcome (p = 0.04).ConclusionsCerebral physiological monitoring provides important prognostic information in sCH. Optimal targets differ from supratentorial acute brain injuries, with an apparent benefit of higher CPP in sCH. ICP, CPP, and ΔCPPopt remain central, warranting larger multi-center studies to define sCH-specific targets.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13054-026-06136-0.

Dizziness is a prevalent clinical complaint, and determining the underlying etiology can be challenging. Posterior fossa masses have been observed to cause vertigo, with presentations very similar to Meniere’s disease. In this report, we describe a case of a patient who presented with recurrent episodes of Meniere’s-like vertigo in the setting of a posterior fossa meningioma, who underwent surgical resection of the tumor with significant improvement postoperatively. We postulate that these symptoms were caused by secondary endolymphatic hydrops and were able to demonstrate improvement in high-frequency vestibulo-ocular reflex with pre- and postoperative video head impulse testing.

Abstract Extradural posterior fossa decompression is widely used in symptomatic Chiari I malformation. Minimally invasive endoscopic approaches aim to reduce surgical morbidity while preserving decompression efficacy. The objective of this study is to compare operative efficiency and perioperative morbidity between endoscopic and conventional microsurgical extradural decompression techniques over an extended institutional experience. A retrospective comparative study of 25 consecutive adult patients undergoing extradural posterior fossa decompression for Chiari I malformation over an 8-year period was performed. Patients were divided into an endoscopic group (n = 13) and a microsurgical group (n = 12). Operative time, estimated blood loss, hospital stay, and perioperative complications were analyzed. The present cohort represents an extension of a previously published pilot series with additional patients and expanded perioperative evaluation. Mean operative time was comparable between endoscopic and microsurgical techniques (65 vs. 64 minutes). Estimated blood loss was lower in the endoscopic group (110 mL) compared with the microsurgical group (180 mL), representing a 39% reduction. Mean hospital stay was shorter in the endoscopic group (1.75 days) versus the microsurgical group (2.67 days). No cerebrospinal fluid leakage, reoperation, or neurological deterioration occurred in either group. Delayed wound healing was more frequent in the microsurgical group, whereas one case of delayed occipital neuralgia was observed in the endoscopic group. Endoscopic extradural decompression provides operative efficiency equivalent to the microsurgical approach while reducing intraoperative blood loss and shortening hospitalization. Technical refinement and standardization appear critical in optimizing surgical morbidity without compromising decompression safety.

Morphological analysis of posterior fossa in Apert and Crouzon syndromes before and after posterior cranial vault expansion.