Oculomotor Impairments in Children After Posterior Fossa Tumors Treatment.

Posterior fossa tumors (PFT) are the most common pediatric brain tumors, and the study of the somatic and cognitive status of PFT survivors still remains a critical problem. Since cerebellar damage can affect eye movement centers located in the vermis and hemispheres, such patients suffer from disturbances in visual perception, visual-spatial functions, reading, etc. Our investigation aimed at describing oculomotor impairments in PFT survivors linked to core oculomotor functions assessed through eye tracking method: gaze holding, reflexive saccades, and organization of voluntary saccades and their dependency on age at tumor diagnosis. Also, we investigated the relationship between oculomotor functions and ataxia measured with International Cooperative Ataxia Rating Scale (ICARS). A total of 110 children (patients and age-matched healthy controls, aged 9-17 years old) participated in the study. We found that the earlier the child had a tumor, the more impaired gaze holding (p = 0.0031) and fewer isometric saccades (p = 0.035) were observed at the time of examination. The above-mentioned functions in healthy controls improved with age. Visual scanning was also impaired compared to controls but was not related to age at diagnosis. A positive correlation between ICARS scores and number of hypermetric saccades (r = 0.309, p = 0.039), but no correlation with the number of hypometric saccades (r = - 0.008, p = 0.956). Furthermore, number of hypometric saccades did not differ between patients and controls (p = 0.238). Thus, primarily hypermetric saccades can be considered a prominent oculomotor symptom of cerebellar tumors. Our study provides basis for new methods of PFT diagnosis and rehabilitation procedure evaluation, both playing essential roles in modern pediatric neurooncology.

Posterior fossa tumors in children: current insights.

While in adults most intracranial tumors develop around the cerebral hemispheres, 45 to 60% of pediatric lesions are found in the posterior fossa, although this anatomical region represents only 10% of the intracranial volume. The latest edition of the WHO classification for CNS tumors presented some fundamental paradigm shifts that particularly affected the classification of pediatric tumors, also influencing those that affect posterior fossa. Molecular biomarkers play an important role in the diagnosis, prognosis, and treatment of childhood posterior fossa tumors and can be used to predict patient outcomes and response to treatment and monitor its effectiveness. Although genetic studies have identified several posterior fossa tumor types, differing in terms of their location, cell of origin, genetic mechanisms, and clinical behavior, recent management strategies still depend on uniform approaches, mainly based on the extent of resection. However, significant progress has been made in guiding therapy decisions with biological or molecular stratification criteria and utilizing molecularly targeted treatments that address specific tumor biological characteristics. The primary focus of this review is on the latest advances in the diagnosis and treatment of common subtypes of posterior fossa tumors in children, as well as potential therapeutic approaches in the future.   Conclusion: Molecular biomarkers play a central role, not only in the diagnosis and prognosis of posterior fossa tumors in children but also in customizing treatment plans. They anticipate patient outcomes, measure treatment responses, and assess therapeutic effectiveness. Advances in neuroimaging and treatment have significantly enhanced outcomes for children with these tumors. What is Known: • Central nervous system tumors are the most common solid neoplasms in children and adolescents, with approximately 45 to 60% of them located in the posterior fossa. • Multimodal approaches that include neurosurgery, radiation therapy, and chemotherapy are typically used to manage childhood posterior fossa tumors What is New: • Notable progress has been achieved in the diagnosis, categorization and management of posterior fossa tumors in children, leading to improvement in survival and quality of life.

Effect of administration of tranexamic acid on blood loss and transfusion requirements in children undergoing posterior fossa tumor excision: a retrospective cohort study.

BACKGROUND: Surgical resection of posterior fossa tumors (PFT) in the pediatric age group often results in significant intraoperative blood loss. The primary objective was to assess the effect of tranexamic acid (TXA) on blood loss and transfusion requirement in pediatric patients undergoing excision of PFT. METHODS: In this retrospective study, all pediatric patients ≤ 18 years, who underwent PFT resection over a period of 7 years, were included. The patient and surgical characteristics, estimated blood loss (EBL), the need for blood and blood product transfusion, use of crystalloids, vasopressors, and any adverse events like seizures and thromboembolic events were recorded and compared between Group A who received TXA and Group B who did not. RESULTS: The study included 50 patients, out of which 36 belonged to Group A and 14 to Group B. The median age was 8 years (IQR, 2-17) and the mean BMI was 16.46 ± 4.11 kg/m2. The mean EBL was 224.29 ± 110.36 ml in group A (n = 36) and 362 ± 180.11 ml in group B (n = 14) (p = 0.007). The intraoperative volume of crystalloid use was significantly higher in group B (p = 0.04). The requirement of blood and blood product transfusion was similar between the groups, but the volume of blood transfusion per kg body weight was higher in group B, 8.3 (IQR, 6.7-11.1) ml/kg in Group A versus 10.5 (IQR, 8.1-16.1) ml/kg in Group B (p-value 0.3). The rates of complications noted in the form of seizures and thromboembolic events were comparable. CONCLUSION: The use of TXA in the pediatric population undergoing PFT resection aids in reducing blood loss during the surgery without increasing complications.

Quality of life in survivors of pediatric medulloblastoma: a systematic review and meta-analysis.

INTRODUCTION: Medulloblastoma (MB) is the most common malignant pediatric brain tumor. The mainstay of treatment is maximum surgical resection and craniospinal radiation, which may be followed by chemotherapy. The debilitating effect of the tumor and the intensive treatment approaches in MB lead to long-term neuropsychological, physical, and chronic medical problems. We conducted a systematic review to assess the quality of life (QoL) in the long-term survivors of MB and the factors leading to compromised QoL. METHODS: We utilized the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for our review. A comprehensive literature search was performed using PubMed, Cochrane Library, Digital Commons Network, and Wiley Online Library databases to search for articles having quality of life, medulloblastoma, and pediatric survivors in title or abstract. We removed duplicates and screened through titles, and full texts. Twelve articles were included in our study. Articles using and reporting all domains of PaedsQL were included in the meta-analysis. The PaedsQL scores of survivors and their caregivers were compared. Subgroup analysis was conducted for craniospinal and proton radiotherapy groups. RESULTS: As compared to other posterior fossa tumors, MB survivors have the lowest QoL scores. There is a difference in the perception of QoL of survivors between caregivers and survivors themselves with survivors rating themselves higher in several domains. The overall PaedsQL scores were significantly different for both groups (p < 0.001). Subgroup analysis showed that the difference between those who were treated with craniospinal or proton radiation was not significant (p = 0.76). For the subscales, physical (p = 0.005), psychosocial (p = 0.0003), and school (p = 0.03) perceptions were significantly different for the survivors and their caregivers; however, psychosocial (p = 0.80) and emotional (p = 0.93) scales were not different for the survivors or caregivers. Patient characteristics related to a worse QoL included disease severity, metastatic disease, lesser family income, smaller current ventricle size, need for permanent hydrocephalus treatment, and lesser age at diagnosis. CONCLUSION: An analysis of various studies, using different measures of QoL, concludes that QoL is compromised in all pediatric survivors of MB; however, the perception of QoL of the survivors is better than objective or caretaker-rated QoL.

Resection of posterior fossa tumors in the semi-sitting position in children younger than 4 years of age.

PURPOSE: The semi-sitting position for resection of posterior fossa tumors is a matter of ongoing debate. Here we report about our experience with this approach in children younger than 4 years of age. METHODS: We retrospectively analyzed data of children younger than 4 years of age operated on in our institution in the semi-sitting position over a 15-year period. Patients were intraoperatively monitored for venous air embolism (VAE) by transthoracic Doppler (TTD) or transesophageal echocardiography (TEE). The severity of VAE was classified according to the Tübingen grading scale. Intraoperative incidents of VAE were recorded and the patients' course was followed postoperatively with a special focus on possible complications. RESULTS: Twenty-four children (18 boys, 6 girls) were operated on in the semi-sitting position (26 operations). Mean age was 2.2 years (± 1.0), range between 0.4 and 3.9 years. External ventricular drains were inserted in 18 children with hydrocephalus preoperatively. VAE was detected in 6 instances during surgery (6/26 (23.1%)). In 3 patients with grade 1 VAE, no additional treatment was necessary. In one patient with grade 2 VAE, intracardiac air suction via the central venous catheter was performed, and in two patients with grade 4 VAE, additional cathecholamine-infusion was administered. No major intraoperative complications occurred. Postoperative CT images showed pneumocephalus in all children. In two children, small asymptomatic impression skull fractures at the site of the Mayfield pin occurred. Revision surgery was necessary in one child with a suboccipital CSF fistula. CONCLUSION: The semi-sitting position for resection of tumors in the posterior fossa in children younger than 4 years of age can be safely performed in experienced centers taking special caution to detect and treat potential complications in an interdisciplinary setting.

Placement of EVD in pediatric posterior fossa tumors: safe and efficient or old-fashioned? The Vienna experience.

PURPOSE: The perioperative treatment of hydrocephalus in pediatric posterior fossa tumors with an external ventricular drain (EVD) is the treatment of choice in our center. We analyzed our experience in using EVD concerning safety and effectivity. METHODS: This is a single-center retrospective cohort study of 100 consecutive pediatric patients who underwent resection for a newly diagnosed tumor in the posterior fossa between 2011 and 2022. RESULTS: Of the 100 patients with posterior fossa tumors, 80 patients (80%) had radiological signs of hydrocephalus at presentation, 49 patients (49%) of whom underwent placement of an EVD. In 40 patients, the EVD was inserted at a mean of 2.25 days prior to the tumor resection; 9 had the EVD inserted during tumor resection (frontal trajectory in 7 patients, occipital trajectory in 2 patients). Histology revealed pilocytic astrocytoma in 48 patients, medulloblastoma in 32, ependymoma in 11, and other histologic entities in 9 patients. Gross total/near-total resection was achieved in 46 (95.83%) of the 48 pilocytic astrocytomas, 30 (93.75%) of the 32 medulloblastomas, and 11 (100%) of the 11 ependymomas. The mean number of total days with the EVD in place was 8.61 ± 3.82 (range 2-16 days). The mean number of days with an EVD after tumor resection was 6.35 ± 3.8 (range 0-16 days). EVD-associated complications were seen in 6 patients (12.24%) including one infection. None of these resulted in a worse clinical course or any long-term sequelae. Permanent CSF diversion at 6 months after surgery was necessary in 13 patients (13%), including two VP shunt, two SD-shunt, six endoscopic third ventriculostomy (ETV), and three combined VP shunt and ETV procedures. Patients with a medulloblastoma or ependymoma had a higher rate of permanent CSF diversion needed than the group of pilocytic astrocytoma patients (27.9% versus 2.13%, p < 0.001). In patients with metastatic disease, 7 of 17 patients (41.18%) needed a permanent CSF diversion, compared to 6 of 83 patients (7.23%) in the group without metastasis (p = 0.001). CONCLUSION: The treatment of hydrocephalus in pediatric posterior fossa tumors with an EVD as a temporary measure is safe and effective, provided that a multi-professional understanding for its handling is given and there is no need for a long transport of the children.

Surgical outcome of children with medulloblastoma: a retrospective study of a 405-patient series from Children's Cancer Hospital Egypt (CCHE-57357).

PURPOSE: To analyze the impact of increasing the extent of resection (EOR) on the survival rates and on the surgical outcome of children with medulloblastoma. METHODS: A series of consecutive 405 children operated for medulloblastoma between July 2007 and April 2018 was identified. The details of pre-operative data, surgical interventions, post-operative complications, and survival rates were analyzed. RESULTS: The Kaplan-Meier (KM) analysis showed no advantage of gross total resection (GTR) over near and subtotal resection regarding over all (OS) (p=0.557) and progression free survival (PFS) (p=0.146). In the same time, increasing the EOR was not associated with higher morbidity. Tumor dissemination at onset correlated to worse OS (KM: p=0.003, OR 1.999, 95% CI: 1.242-3.127; p = 0.004) and PFS (KM: p<0.001, Cox: OR 2.171, 95% CI: 1.406-3.353; p<0.001). OS was significantly affected in patients < 3 years old (KM: p=0.011, OR 2.036, 95% CI: 1.229-3.374; p = 0.006), while PFS was worse among patients who had pre-op seizures (KM: p=0.036, Cox: OR 2.852, 95% CI: 1.046-7.773; p=0.041) or post-op pseudomeningocele (KM: p=0.021, Cox: OR 2.311, 95% CI: 1.123-4.754; p=0.023). CONCLUSIONS: Although surgical excision of medulloblastoma is the standard of care, there was no significant benefit for GTR over near or subtotal resection on the OS or PFS rates that are mainly influenced by the patient's age and tumor dissemination. However, GTR should be targeted, as it is not associated with increased incidence of mutism or other surgery-related complications.

Neuropsychological Profile in Children with Posterior Fossa Tumors with or Without Postoperative Cerebellar Mutism Syndrome (CMS).

Cerebellar mutism syndrome (CMS) is a common surgical sequela in children following posterior fossa tumor (PFT) resection. Here, we analyze the neuropsychological features associated with PFT in children, focusing particularly on the differential profiles associated with the presence or absence of CMS after surgery. We further examine the effect of post-resection treatments, tumor type, and presence/absence of hydrocephalus on surgical outcome. Thirty-six patients diagnosed with PFT (19 with and 17 without CMS) and 34 age- and gender-matched healthy controls (HCs) were recruited. A comprehensive neuropsychological evaluation was conducted in all patients postoperatively and in HCs, including an assessment of general cognitive ability, motor skills, perception, language, memory, attention, executive functions, and academic competence. CMS was found to be a clinical marker of lower neuropsychological profile scores across all cognitive domains except auditory-verbal processing and visual memory tasks. PFT patients not presenting CMS exhibited milder impairment in intellectual functioning, motor tasks, reasoning, language, verbal learning and recall, attention, cognitive executive functions, and academic competence. High-grade tumors were associated with slower processing speed and verbal delayed recall as well as alterations in selective and sustained attention. Hydrocephalus was detrimental to motor functioning and nonverbal reasoning. Patients who had undergone surgery, chemotherapy, and radiotherapy presented impaired processing speed, verbal learning, and reading. In addition to the deleterious effects of PFT, post-resection PFT treatments have a negative cognitive impact. These undesired consequences and the associated tumor-related damage can be assessed using standardized, long-term neuropsychological evaluation when planning rehabilitation.

Eye Movements and White Matter are Associated with Emotional Control in Children Treated for Brain Tumors.

OBJECTIVE: Children treated for brain tumors often experience social and emotional difficulties, including challenges with emotion regulation; our goal was to investigate the attention-related component processes of emotion regulation, using a novel eye-tracking measure, and to evaluate its relations with emotional functioning and white matter (WM) organization. METHOD: Fifty-four children participated in this study; 36 children treated for posterior fossa tumors, and 18 typically developing children. Participants completed two versions of an emotion regulation eye-tracking task, designed to differentiate between implicit (i.e., automatic) and explicit (i.e., voluntary) subprocesses. The Emotional Control scale from the Behavior Rating Inventory of Executive Function was used to evaluate emotional control in daily life, and WM organization was assessed with diffusion tensor imaging. RESULTS: We found that emotional faces captured attention across all groups (F(1,51) = 32.18, p < .001, η2p = .39). However, unlike typically developing children, patients were unable to override the attentional capture of emotional faces when instructed to (emotional face-by-group interaction: F(2,51) = 5.58, p = .006, η2p = .18). Across all children, our eye-tracking measure of emotion regulation was modestly associated with the parent-report emotional control score (r = .29, p = .045), and in patients it was associated with WM microstructure in the body and splenium of the corpus callosum (all t > 3.03, all p < .05). CONCLUSIONS: Our findings suggest that an attention-related component process of emotion regulation is disrupted in children treated for brain tumors, and that it may relate to their emotional difficulties and WM organization. This work provides a foundation for future theoretical and mechanistic investigations of emotional difficulties in brain tumor survivors.

Posterior Fossa Society Consensus Meeting 2018: a synopsis.

PURPOSE: The Posterior Fossa Society (PFS) was founded 4 years ago to systematically gather and exchange information on the post-operative (CMS) and cerebellar cognitive affective syndrome (CCAS). With its consensus meetings, the PFS orchestrates research studies in the field of cerebellar injury and progresses the knowledge of post-operative pediatric cerebellar mutism syndrome (CMS). In this article, we captured the 3-day program of presentations, group discussions, interactive workshops, and dialogue, highlighting the key topic areas of CMS and its research advances. METHODS: This synopsis is based on the third consensus meeting which was held in Reykjavik, Iceland, in August 2018. RESULTS: Three working groups have been defined to drive the future research priorities on post-surgical CMS: (i) refining definition and symptoms scoring of CMS; (ii) understanding the pathogenesis and enhancing risk-stratification strategies; and (iii) developing rehabilitation approaches and protocols. CONCLUSIONS: The third consensus meeting highlighted a unanimous desire for data-driven information to advance the knowledge and guide future research efforts. The PFS constitutes an established and expanding network of multi-disciplinary expertise that can facilitate the development of collaborative studies and produce official guidelines on the topic.

Posterior fossa syndrome: Review of the behavioral and emotional aspects in pediatric cancer patients.

Medulloblastoma, the most common malignant brain tumor of childhood, occurs in the posterior fossa, the part of the intracranial cavity that contains the brainstem and the cerebellum. The cerebellum is involved in many complex aspects of human behavior and function, and when it is disrupted or insulted, this can lead to significant sequelae in children with posterior fossa tumors. A constellation of impairing and distressing symptoms, including mutism, ataxia/hypotonia, and emotional lability, develops in approximately 25% of children after the surgical resection of posterior fossa tumors. These symptoms may impede treatment and frequently require intervention in order for children to be able to participate in their care. The eventual recovery of speech occurs for most, but with slowly improving dysarthria over many months. Behavioral changes and emotional lability also occur. This phenomenon has been classified differently by different investigators over the past 35 years. For the purposes of this article, the term posterior fossa syndrome is used to refer to the neuropsychiatric and behavioral features that compose this condition. The current review summarizes the development of the clinical understanding of this phenomenon with a focus on near- and long-term psychosocial and psychiatric implications. Also, clinical examples of the presentation, management, and lasting implications of this syndrome are provided. This review is intended to be a resource for clinicians who treat affected children. Cancer 2017;123:551-559. © 2016 American Cancer Society.

Regulatory T cell subsets in patients with medulloblastoma at diagnosis and during standard irradiation and chemotherapy (PBTC N-11).

BACKGROUND: We evaluated circulating levels of immunosuppressive regulatory T cells (Tregs) and other lymphocyte subsets in patients with newly diagnosed medulloblastoma (MBL) undergoing surgery compared to a control cohort of patients undergo craniectomy for correction of Chiari malformation (CM) and further determined the impact of standard irradiation and chemotherapy on this cell population. METHODS: Eligibility criteria for this biologic study included age 4-21 years, patients with CM undergoing craniectomy (as non-malignant surgical controls) and receiving dexamethasone for prevention of post-operative nausea, and those with newly diagnosed posterior fossa tumors (PFT) undergoing surgical resection and receiving dexamethasone as an anti-edema measure. Patients with confirmed MBL were also followed for longitudinal blood collection and analysis during radiotherapy and chemotherapy. RESULTS: A total of 54 subjects were enrolled on the study [22-CM, 18-MBL, and 14-PFT]. Absolute number and percentage Tregs (defined as CD4+CD25+FoxP3+CD127low/-) at baseline were decreased in MBL and PFT compared to CM [p = 0.0016 and 0.001, respectively). Patients with MBL and PFT had significantly reduced overall CD4+ T cell count (p = 0.0014 and 0.0054, respectively) compared to those with CM. Radiation and chemotherapy treatment in patients with MBL reduced overall lymphocyte counts; however, within the CD4+ T cell compartment, Tregs increased during treatment but gradually declined post therapy. CONCLUSIONS: Our results demonstrate that patients with MBL and PFT exhibit overall reduced CD4+ T cell counts at diagnosis but not an elevated proportion of Tregs. Standard treatment exacerbates lymphopenia in those with MBL while enriching for immunosuppressive Tregs over time.

Management of hydrocephalus in pediatric metastatic tumors of the posterior fossa at presentation.

PURPOSE: Presence of metastases in newly diagnosed pediatric posterior fossa tumors (PFT) is not a rare situation, but optimal treatment of associated hydrocephalus in these children has remained undetermined. METHODS: Twenty-nine children treated between January 2005 and December 2015 for a metastatic PFT associated with hydrocephalus constituted the study cohort. Patients were divided into three groups: ventriculoperitoneal shunt (VPS), endoscopic third ventriculostomy (ETV), and temporary ventricular drainage before or during tumor resection (PVD). RESULTS: There were 4 VPS, 18 ETV, and 7 PVD. The global incidence of CSF diversion failure was 52%. No case of dysfunction or dissemination of metastatic cells occurred in the VPS group. Recurrence of hydrocephalus occurred in 55% of the ETV group. Presence of multiple macroscopic metastases and CSF metastatic cells after tumor surgery was associated with ETV failure. Fifty-seven percent of the children in the PVD group were reoperated after an average time of 53 days. Specific oncologic treatment was initiated earlier in the VPS group (11 days) compared to ETV (27 days) and PVD (23 days) groups. CONCLUSIONS: ETV should be avoided in cases of multiple macroscopic metastases, and children who underwent ETV must be followed carefully when metastatic cells are present in CSF after tumor surgery. External ventricular drainage before or during surgical removal should not be considered as a final option to treat hydrocephalus. VPS remains a safe alternative in this situation and allows an early specific oncologic treatment.

Posterior fossa tumors in children: developmental anatomy and diagnostic imaging.

INTRODUCTION: Modern understanding of the relation between the mutated cancer stem cell and its site of origin and of its interaction with the tissue environment is enhancing the importance of developmental anatomy in the diagnostic assessment of posterior fossa tumors in children. The aim of this review is to show how MR imaging can improve on the exact identification of the tumors in the brainstem and in the vicinity of the fourth ventricle in children, using both structural imaging data and a precise topographical assessment guided by the developmental anatomy. RESULTS: The development of the hindbrain results from complex processes of brainstem segmentation, ventro-dorsal patterning, multiple germinative zones, and diverse migration pathways of the neural progenitors. Depending on their origin in the brainstem, gliomas may be infiltrative or not, as well as overwhelmingly malignant (pons), or mostly benign (cervicomedullary, medullo-pontine tegmental, gliomas of the cerebellar peduncles). In the vicinity of the fourth ventricles, the prognosis of the medulloblastomas (MB) correlates the molecular subtyping as well as the site of origin: WNT MB develop from the Wnt-expressing lower rhombic lip and have a good prognosis; SHH MB develop from the Shh-modulated cerebellar cortex with an intermediate prognosis (dependent on age); recurrences are local mostly. The poor prognosis group 3 MB is radiologically heterogeneous: some tumors present classic features but are juxtaventricular (rather than intraventricular); others have highly malignant features with a small principal tumor and an early dissemination. Group 4 MB has classic features, but characteristically usually does not enhance; dissemination is common. Although there is as yet no clear molecular subgrouping of the ependymomas, their sites of origin and their development can be clearly categorized, as most develop in an exophytic way from the ventricular surface of the medulla in clearly specific locations: the obex region with expansion in the cistern magna, or the lateral recess region with expansion in the CPA and prepontine cisterns (cerebellar ependymomas, and still more intra-brainstem ependymomas are rare). Finally, almost all cerebellar gliomas are pilocytic astrocytomas. CONCLUSIONS: A developmental and anatomic approach to the posterior fossa tumors in children (together with diffusion imaging data) provides a reliable pre-surgical identification of the tumor and of its aggressiveness.

A systematic review of neuropsychological outcomes following posterior fossa tumor surgery in children.

PURPOSE: Central nervous system tumors are the most common solid tumors in the pediatric population. As children with central nervous system (CNS) tumors are surviving into adolescence and adulthood, more research is being focused on the long-term cognitive outcomes of the survivors. This review examines the literature on different cognitive outcomes of survivors of different childhood posterior fossa CNS tumor types. METHODS: The authors reviewed the literature for articles published from 2000 to 2012 about long-term neuropsychological outcomes of children diagnosed with posterior fossa brain tumors before the age of 18, which distinguished between histological tumor types, and had a minimum follow-up of 3 years. RESULTS: The literature search returned 13 articles, and a descriptive analysis was performed comparing intelligence quotient (IQ), attention/executive function, and memory components of 456 survivors of childhood posterior fossa tumors. Four articles directly compared astrocytoma and medulloblastoma survivors and showed medulloblastoma survivors fared worse in IQ, attention/executive function, and memory measurements. Five articles reporting medulloblastomas found IQ, attention, and memory scores to be significantly below the standardized means. Articles examining astrocytoma survivors found IQ scores within the normal range for the population. Survivors of ependymomas reported 2/23 survivors impaired on IQ scores, while a second study reported a significant number of ependymoma survivors lower than the expected population norm. CONCLUSIONS: Tumor histopathology and the type of postoperative adjuvant therapy seem to have a significant impact on the long-term neuropsychological complications of pediatric posterior fossa CNS tumor survivors. Age at diagnosis and treatment factors are important variables that affect the outcomes of the survivors.

Posterior fossa tumors in infants and neonates.

INTRODUCTION: Management of posterior fossa tumors in infants and neonates is challenging. The characteristics of the young babies make surgery very difficult, sometimes precluding a safe complete removal. METHODS: A review of the literature was undertaken to examine the incidence, histology, surgical aspects, and prognosis of posterior fossa tumors in the first year of life. Therapeutical strategies of the most frequent tumor types are also discussed in detail. RESULTS: Histology is dominated by tumors with aggressive behavior, such as medulloblastomas, atypical teratoid/rhabdoid tumors, and anaplastic ependymomas. The most important surgical considerations in small children are the small circulating blood volume; the poor thermoregulation; and incomplete maturation of the brain, of the skull, and of the soft tissue. Treatment toxicity is inversely related to the age of the patients. Radiation therapy is usually considered as contraindicated in young children, with few exceptions. Proton therapy is a promising tool, but access to this kind of treatment is still limited. The therapeutic limitations of irradiation render resection of this tumor and adjuvant chemotherapy often the only therapeutic strategy in many cases. CONCLUSIONS: The overall prognosis remains dismal because of the prevalent aggressive histologies, the surgical challenges, and the limitations of adjuvant treatment. Nevertheless, the impressive improvements in anesthesiology and surgical techniques allow, in the vast majority of the cases, complete removal of the lesions with minor sequelae in high-volume referral pediatric centers.

Cerebellar mutism.

INTRODUCTION: Cerebellar mutism (CM) is defined as a peculiar form of mutism that may complicate the surgical excision of posterior cranial fossa tumor. The incidence is variable in the literature, occurring in up to one third of cases in some series. Commonly occurring peculiar features of CM are delayed onset following surgery, limited duration, and spontaneous recovery usually associated with dysarthria. METHODS: A review has been performed concerning anatomical substrates and circuits actually considered to be involved in the development of cerebellar mutism, as well as risk factors for its development that have been documented in the literature. Attention has also been given to the long-term prognosis and the possibilities of rehabilitation that can be considered in these children, which has been compared with the authors' institutional experience. RESULTS AND CONCLUSIONS: Tumor infiltration of the brainstem seems to represent the most relevant feature related to the development of CM, along with the histological diagnosis of medulloblastoma. On the other hand, hydrocephalus does not represent an independent risk factor. The higher rate of CM in children seems to be related to the higher incidence in children of tumors with malignant histology and brain stem involvement. Surgical technique does not seem to have a definite role; in particular, the use of a telovelar approach as compared to vermian split to reach the fourth ventricle extension of the tumor has not been demonstrated to prevent the development of cerebellar mutism. Concerning long-term prognosis, around one third of the children who develop cerebellar mutism after surgery have a persistent dysarthria, the remaining ones showing a residual phonological impairment. Long-term dysarthric features tend to be more severe and less prone to recovery in children presenting at diagnosis with associated combined procedural memory and defective neurocognitive functions.

The role of precentral cerebellar vein in neurosurgery: An in-depth review of anatomy, implications, and risks.

Background: The Precentral Cerebellar Vein (PCV) plays a crucial role as an anatomical landmark in neurosurgery, and the possibility of its safe sacrifice is controversial. Understanding its anatomical nuances and clinical implications is fundamental in enhancing neurosurgical practice. Methods: A systematic review following PRISMA guidelines was conducted to consolidate literature on the PCV. PubMed, Scopus, and Web of Science were systematically searched using predefined criteria. Studies providing complete research texts in English, focusing on the PCV's surgical anatomy and neurosurgical implications were included. Results: Fourteen articles met inclusion criteria, exploring the PCV's anatomical variations, trajectory, dimensions, and connections. The PCV's utility in localizing posterior fossa tumors was underscored, aiding in surgical precision. However, sacrifices of the PCV or minor veins for access to quadrigeminal areas posed postoperative risks, emphasizing the need for careful preoperative planning. Additionally, the PCV's diagnostic value in venous malformations and developmental anomalies was highlighted. Conclusions: This comprehensive review accentuates the pivotal role of the PCV in neurosurgery. While serving as a vital guide in procedures, it poses potential risks when manipulated. Understanding its multifaceted significance, from anatomy to clinical implications, is paramount for informed decision-making and minimizing complications in neurosurgical interventions.

Machine Learning Analysis in Diffusion Kurtosis Imaging for Discriminating Pediatric Posterior Fossa Tumors: A Repeatability and Accuracy Pilot Study.

Background and purpose: Differentiating pediatric posterior fossa (PF) tumors such as medulloblastoma (MB), ependymoma (EP), and pilocytic astrocytoma (PA) remains relevant, because of important treatment and prognostic implications. Diffusion kurtosis imaging (DKI) has not yet been investigated for discrimination of pediatric PF tumors. Estimating diffusion values from whole-tumor-based (VOI) segmentations may improve diffusion measurement repeatability compared to conventional region-of-interest (ROI) approaches. Our purpose was to compare repeatability between ROI and VOI DKI-derived diffusion measurements and assess DKI accuracy in discriminating among pediatric PF tumors. Materials and methods: We retrospectively analyzed 34 children (M, F, mean age 7.48 years) with PF tumors who underwent preoperative examination on a 3 Tesla magnet, including DKI. For each patient, two neuroradiologists independently segmented the whole solid tumor, the ROI of the area of maximum tumor diameter, and a small 5 mm ROI. The automated analysis pipeline included inter-observer variability, statistical, and machine learning (ML) analyses. We evaluated inter-observer variability with coefficient of variation (COV) and Bland-Altman plots. We estimated DKI metrics accuracy in discriminating among tumor histology with MANOVA analysis. In order to account for class imbalances, we applied SMOTE to balance the dataset. Finally, we performed a Random Forest (RF) machine learning classification analysis based on all DKI metrics from the SMOTE dataset by partitioning 70/30 the training and testing cohort. Results: Tumor histology included medulloblastoma (15), pilocytic astrocytoma (14), and ependymoma (5). VOI-based measurements presented lower variability than ROI-based measurements across all DKI metrics and were used for the analysis. DKI-derived metrics could accurately discriminate between tumor subtypes (Pillai's trace: p < 0.001). SMOTE generated 11 synthetic observations (10 EP and 1 PA), resulting in a balanced dataset with 45 instances (34 original and 11 synthetic). ML analysis yielded an accuracy of 0.928, which correctly predicted all but one lesion in the testing set. Conclusions: VOI-based measurements presented improved repeatability compared to ROI-based measurements across all diffusion metrics. An ML classification algorithm resulted accurate in discriminating PF tumors on a SMOTE-generated dataset. ML techniques based on DKI-derived metrics are useful for the discrimination of pediatric PF tumors.

Prediction of intraoperative blood loss in pediatric posterior fossa tumors by neuroradiological evaluation: preliminary study.

BACKGROUND: Hemorrhage management is crucial for surgical resection of pediatric posterior-fossa tumors (PPFTs). Tumor volume and vascularity on preoperative magnetic resonance imaging (MRI) can help predict and control intraoperative blood loss (IBL). The present study aimed to assess the correlation between MRI features and IBL in PPFTs. METHODS: Eleven patients treated for PPFTs at our hospital using the transcerebellomedullary fissure approach were enrolled, including five (45.5%) males and six (54.5%) females, with a median age of 10 (range, 4-16) years. Nine patients with medulloblastoma, one with ependymoma, and one with atypical teratoid/rhabdoid tumor were included. Using susceptibility-weighted imaging-based intratumoral susceptibility signal (ITSS) grade as an index of tumor vascularity, we performed univariate analysis of the association of degree of vascularity (ITSS grade 0-2 vs. 3) and multivariate analysis of IBL. RESULTS: Univariate analysis showed that the high vascularity group (ITSS grade 3) had significantly larger tumor volume (p = 0.009) and higher IBL (p = 0.004). In multivariate analysis of age, tumor volume, ITSS grade, cerebral blood volume, and extent of resection, tumor volume was the only significant factor (p = 0.001); however, ITSS grade was also positively associated with IBL (p = 0.074). CONCLUSION: In this study, tumor volume and vascularity of PPFTs were strongly correlated, and tumor volume was the sole factor significantly associated with IBL. This study suggests that ITSS grade and tumor volume collaboratively influence IBL in surgical resection of PPFTs. IBL should be assessed based on MRI features, and suitable treatment strategies should be established.