Cerebellar mutism syndrome (CMS), also known as posterior fossa syndrome, is encountered in a subset of children who have undergone an operative procedure of the posterior cranial fossa, mainly involving the vermis, and the most frequent underlying pathology is proved to be medulloblastoma. The most common characteristics of this syndrome include an often transient, although protracted, language impairment, emotional lability, along with cerebellar, and brainstem dysfunction. Nevertheless, a significant number of patients experience persistent neurological deficits and lasting neurocognitive impairment. A lot of research and clinical studies have been performed in order to better delineate this syndrome. The main obstacles in our way to highlight all aspects of this syndrome were related with an inconsistent nomenclature, poorly defined diagnostic criteria, and uncertainty surrounding risk factors and etiology. Currently, there is a combination of diagnostic criteria that are regarded as prerequisites in order to establish the diagnosis of CMS. These include language impairment and emotional lability, as proposed by the international Board of the Posterior Fossa Society in their consensus statement. Several risk factors are recognized as implicated in the pathogenesis of this syndrome, including midline tumor location, diagnosis of medulloblastoma, younger age at diagnosis, and preoperatively established language impairment. A proposed etiology of CMS includes disruption of the cerebellar outflow tracts, the cerebellar nuclei, and their efferent projections through the superior cerebellar peduncle. Specific treatment for CMS is lacking, and it continues to be directed at symptom management. Our aim is to present a comprehensive narrative review of CMS etiology, diagnosis, risk factors, clinical presentation, and clinical management. Moreover, we attempt to recognize the most widely recognized priorities of the research community in order to expand our knowledge in the era of diagnostics, prevention, and therapeutic options for patients suffering from CM, or who are at risk for development of this syndrome.

Introduction: The entity of the trapped fourth ventricle represents a clinical challenge, as it is a rare entity associated with a wide spectrum of underlying pathologic conditions and the proposed treatment options are restricted and frequently associated with complications and unfavorable long-term outcome. The majority of the affected individuals report a medical history of previous ventriculo-peritoneal shunt infection, as well as a precipitating factor for the entrapment (central nervous system infection, intraventricular hemorrhage, trauma). They come to clinical attention due to symptomatology attributed to mass effect that is exerted by the ballooned fourth ventricle on the brainstem and cerebellum. Materials and Methods: We present our results, extracted from data derived from our medical center 20 years surgical experience and relevant outcomes in 120 pediatric patients diagnosed and managed with entrapped fourth ventricle. They were treated either with fourth ventricle-peritoneal shunt insertion or with an endoscopic approach. The relative efficacy of both techniques was recorded one year and five years after the initial operation and the data underwent statistical analysis. All patients who failed the initial therapeutic option were managed again with the aforementioned techniques, and their long-term results were recorded. Conclusions: We recorded that after one year of follow-up, there were no significant differences in outcome when these two techniques were compared. However, when the results of five-year follow-up were compared between two groups, there was superiority, regarding the functional outcome, of the procedure involving the insertion of a fourth ventricular-peritoneal shunt. The outcome of patients that underwent a salvage procedure of any type did not seem to be different after a one-year follow-up period, being unable to verify the superiority of one technique over the other. However, there seems to be a superiority of the shunt procedure over the endoscopic technique regarding the functional outcome of these patients, five years after their second operation. Nevertheless, these results are only indicative and our data are insufficient to establish a statistical level of significance, probably due to the restricted number of patients that were incorporated in our survey.