OBJECTIVE: Dysphagia is common in individuals who have undergone posterior fossa tumor (PFT) resection and negatively impacts on the individual\'s quality of life, nutritional status, and overall health. We aimed to quantitatively synthesize data from studies of the prevalence of dysphagia following PFT resection.
METHODS: PubMed, Web of Science, the Cochrane Library, Embase, China National Knowledge Infrastructure (CNKI), Wanfang database, and VIP database were searched for case-control and cross-sectional studies that evaluated the prevalence of dysphagia after PFT surgery. Meta-analyses were performed to determine the prevalence of dysphagia. Subgroup and meta-regression analyses were performed to determine the sources of heterogeneity among the studies.
RESULTS: A total of 22 studies were included, involving 20,921 cases. A meta-analysis of the random-effects model showed that the pooled global prevalence of dysphagia following PFT resection was 21.7% (95% confidence interval: 16.9-26.6). The subgroup and meta-regression analyses demonstrated that participant age (P < 0.001), assessment methods (P = 0.004), and geographical region of the study participants (P = 0.001) were sources of heterogeneity among the studies.
CONCLUSIONS: Dysphagia has a high prevalence following PFT resection. Individuals with PFTs who are at a high risk for dysphagia should be identified early through screening. Multidisciplinary diagnosis and treatment of dysphagia are required to improve the outcomes in the early stages after PFT resection.

OBJECTIVE: Pediatric posterior fossa tumor (PFT) survivors experience long-term cognitive sequelae, including memory disorders, for which irradiation is one of the main risk factors. The aims of the present study were to (1) explore the profile of impairment in episodic, semantic, working and procedural memory systems in irradiated versus nonirradiated PFT survivors, and (2) test whether an autobiographical questionnaire and a two-phase ecological test (Epireal) assessing episodic memory are more sensitive to radiation-induced hippocampal damage than commonly used tests.
METHODS: A total of 60 participants (22 irradiated PFT survivors, 17 nonirradiated PFT survivors, and 21 controls) were included in the prospective IMPALA study. They all underwent a broad battery of tests assessing the different memory systems in two 2-day sessions 3 weeks apart. We performed between-groups comparisons and analyzed impairment profiles, using -1.65 SDs as a cut-off. For irradiated patients, correlations were calculated between mean radiation doses to key brain structures involved in memory (hippocampus, cerebellum, and striatum) and corresponding memory scores.
RESULTS: PBT survivors performed significantly more poorly than controls (p < 0.001) on conventional tests of episodic, semantic and working memory: 64% of irradiated patients and 35% of nonirradiated patients had a deficit in at least two memory systems, with episodic memory impairment being more specific to the irradiated group. Epireal had a larger effect size than the other episodic memory tests, allowing us to detect deficits in a further 18% of irradiated patients. These deficits were correlated with the mean radiation dose to the left hippocampus.
CONCLUSIONS: Memory impairment is a frequent long-term cognitive sequela in PFT survivors, especially after radiation therapy. New ecological tests of episodic memory that are more sensitive to radiation-induced deficits than conventional tests could yield specific markers of the toxicity of medial temporal lobe irradiation.

OBJECTIVE: We aim to report the epidemiology, surgical outcomes, and survival rates of pediatric patients with posterior fossa tumors in a large single-center case series.
METHODS: A retrospective analysis was conducted on pediatric patients who underwent surgical treatment for posterior fossa tumors between January 2011 and January 2019.
RESULTS: A total of 135 pediatric patients, with an average age of 7.5 years at diagnosis and a mean follow-up of 35.7 months, were included in the study. Most tumors were located within the midline, with ventriculomegaly observed in 71.4% of the patients. Pilocytic astrocytomas encompassed the majority of tumors (34.1%), followed by medulloblastomas (27.4%) and ependymomas (11.8%). Gross total resection (GTR) was achieved in 71.8% of the patients, with a recurrence rate of 20%. Surgical complications were observed in 25.9% of the patients. GTR significantly impacted 5-year overall survival (OS) and 4-year progression-free survival (PFS) in patients with posterior fossa tumors. Patients who underwent GTR had a 5-year OS of 89.7%, compared to 72.7% for near-total resection and 70.8% for subtotal resection. The 4-year PFS for patients who underwent GTR was 82.5%, whereas it was 63.6% for patients who underwent near-total resection and 54.2% for patients who underwent subtotal resection.
CONCLUSIONS: Surgical resection remains the main treatment for pediatric posterior fossa tumors, and higher resection rates are linked to better survival outcomes. Despite limited resources for molecular diagnosis, our institution has demonstrated that a specialized neurooncological center with a high surgical volume can still achieve favorable survival outcomes for these patients.

OBJECTIVE: As no guidelines for pencil beam scanning (PBS) proton therapy (PT) of paediatric posterior fossa (PF) tumours exist to date, this study investigated planning techniques across European PT centres, with special considerations for brainstem and spinal cord sparing.
METHODS: A survey and a treatment planning comparison were initiated across nineteen European PBS-PT centres treating paediatric patients. The survey assessed all aspects of the treatment chain, including but not limited to delineations, dose constraints and treatment planning. Each centre planned two PF tumour cases for focal irradiation, according to their own clinical practice but based on common delineations. The prescription dose was 54 Gy(RBE) for Case 1 and 59.4 Gy(RBE) for Case 2. For both cases, planning strategies and relevant dose metrics were compared.
RESULTS: Seventeen (89 %) centres answered the survey, and sixteen (80 %) participated in the treatment planning comparison. In the survey, thirteen (68 %) centres reported using the European Particle Therapy Network definition for brainstem delineation. In the treatment planning study, while most centres used three beam directions, their configurations varied widely across centres. Large variations were also seen in brainstem doses, with a brainstem near maximum dose (D2%) ranging from 52.7 Gy(RBE) to 55.7 Gy(RBE) (Case 1), and from 56.8 Gy(RBE) to 60.9 Gy(RBE) (Case 2).
CONCLUSIONS: This study assessed the European PBS-PT planning of paediatric PF tumours. Agreement was achieved in e.g. delineation-practice, while wider variations were observed in planning approach and consequently dose to organs at risk. Collaboration between centres is still ongoing, striving towards common guidelines.

Central neurogenic hyperventilation (CNH) is a rare disease, caused by chemical or mechanical disturbance of respiratory centers. It is characterized by the absence of extracerebral respiratory stimuli. A woman developed severe respiratory alkalosis and lactatemia after resection of a posterior fossa meningioma despite lack of cardio-respiratory or metabolic alterations. Cerebral computed tomography (cCT) revealed edema of the pontomedullary area. Treatment with mannitol and dexamethasone reestablished normal breathing patterns. Lactatemia was likely due to reduced splanchnic lactate utilization. Intracranial pathologies should be suspected in case of hyperventilation without overt reasons. cCT to confirm edema or ischemia and prompt treatment is suggested.

Persistent hydrocephalus is common in children after resection of posterior fossa tumours. However, occurrence of subdural hygroma is very rare. We report the case of a 14-month-old child who presented at a paediatric neurology clinic in Muscat, Oman in 2021 who developed a tense subdural hygroma with stable hydrocephalus, in the early postoperative period, following posterior fossa tumour resection. We describe the distinctive clinical, radiological and pathological features associated with the development of a tense subdural hygroma. We also discuss the management by cerebrospinal fluid diversion, which includes either a ventriculoperitoneal or subduroperitoneal shunt. This unique condition is distinguished from external hydrocephalus by features that are critical to the management strategy.

UNASSIGNED: Hemangioblastomas are benign vascular neoplasms, World Health Organization grade I, with the most frequent location in the cerebellum. Complete microsurgical resection can be a challenge due to excessive bleeding, which is why preoperative embolization takes importance.
UNASSIGNED: Two clinical cases are presented, a 25-year-old woman and a 75-year-old man, who presented with intracranial hypertension symptoms due to obstructive hydrocephalus; a ventriculoperitoneal shunt was placed in both cases; in addition, they presented with cerebellar signs. Both underwent embolization with ethylene vinyl alcohol copolymer, with blood flow reduction. After that, they underwent microsurgical resection within the 1st-week post embolization, obtaining, in both cases, gross total resection without hemodynamic complications, with clinical improvement and good surgical outcome. It is worth mentioning that surgical management is the gold standard that allows a suitable surgical approach, like in our patients, for which a lateral suboccipital craniotomy was performed.
UNASSIGNED: Solid hemangioblastomas are less frequent than their cystic counterparts. The treatment is the surgical resection, which is a challenge and always has to be considered as an arteriovenous malformation in the surgical planning, including preoperative embolization to reduce perioperative morbidity and mortality and get good outcomes.

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OBJECTIVE: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.

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