Cerebellar mutism syndrome: current approaches to minimize risk for CMS.

PURPOSE: Cerebellar mutism syndrome (CMS) is a serious source of morbidity following posterior fossa surgery in the pediatric population. However, methods for effectively decreasing its incidence and impact remain unclear. It is our aim to examine the impact of adjusting surgical factors, namely the use of a telovelar approach and avoidance of cavitronic ultrasonic aspirator, on the incidence of CMS in our population as well as outlining potential pre-, intra-, and postoperative factors that may contribute to its development. METHODS: Retrospective review was performed to identify patients undergoing posterior fossa surgery for resection of a medulloblastoma. Demographic, surgical, and postoperative data were collected. These data were analyzed for possible correlations to the risk of developing CMS via univariate analysis. For factors found to be significant, a multivariate analysis was performed to assess their independence. RESULTS: Seven of 65 patients (10.8%) developed CMS postoperatively. Factors found to be significantly associated with a higher risk of CMS were the degree of retraction utilized during the procedure (p = 0.0000) and incision of the vermis (p = 0.0294). Although they did not reach the threshold of statistical significance, tumor vascularity (p = 0.19), adoption of a transvermian approach (p = 0.19), and lack of intraoperative imaging (p = 0.17) exhibited strongly suggestive trends towards a correlation with CMS. DISCUSSION: In an effort to reduce the incidence and severity of CMS in our population, our institution adopted surgical practices that minimize tissue trauma and mitigate postoperative edema. This included the use of a telovelar over a transvermian approach to obviate the need for vermian incision, avoidance of the CUSA, and minimization of heavy retraction during surgery. This was successful in reducing the incidence of CMS from 39% in our medulloblastoma patients to 10.8%. The development of CMS after posterior fossa surgery appears to be a "two-hit" phenomenon requiring a combination of existing predisposition, surgical injury, and postoperative exacerbation. Therefore, it is critical to identify the factors involved at each stage and investigate treatments to target them appropriately.

Actualización de un modelo tentativo del mutismo selectivo / Update of a tentative model of selective mutism

El mutismo selectivo es un trastorno del comportamiento infanto-juvenil de inicio temprano (generalmente entre los 3 y los 5 años) que consiste en la resistencia al habla o su inhibición en situaciones sociales concretas, caracterizadas por la presencia de extraños, personas a las que no se habla o a las que se ha dejado de hablar, lugares en los que no se habla o donde el niño piensa que puede ser escuchado por quien no quiere, etc. Su escasa prevalencia lo convierte en un trastorno de la conducta raro y la revisión de la literatura confirma que la ansiedad es la alteración prominente en quienes lo presentan, lo que ha llevado a que en la última edición del Manual diagnóstico y estadístico de los trastornos mentales (Asociación Americana de Psiquiatría, DSM-5; APA, 2013) haya sido reclasificado como un trastorno de ansiedad. Este hecho, así como los avances en su investigación y los retos que estos plantean respecto de su evaluación y tratamiento hacen necesaria una revisión y actualización de las propuestas explicativas existentes. Este es el marco en el que se inserta el trabajo que presentamos

Selective mutism is a disorder of early-onset behavior (usually between 3 and 5 years) consisting in a resistance to speech or its inhibition in specific social situations, characterized by the presence of strangers, people who are not spoken to or to whom the child has stopped talking, places where the child doesn't speak or where the child thinks he/she can be heard by unwanted people, etc. Its low prevalence makes it a rare behavior disorder and the review of the literature confirms that anxiety is the prominent alteration in those who present it, which has led to the result that in the last edition of the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, DSM-5; APA, 2013) the behavior has been reclassified as an anxiety disorder. This fact, as well as the advances in its research and the challenges that it poses regarding its evaluation and treatment, make it necessary to review and update the existing explanatory proposals. This is the framework of the work presented here

Experiences with the telovelar approach to fourth ventricular tumors in children.

BACKGROUND: Fourth ventricular tumors are amongst the most common tumors in the pediatric population. Traditionally, these tumors are approached through the cerebellar vermis, but the telovelar approach is now becoming widespread. Posterior fossa syndrome/cerebellar mutism is a complication of surgery for fourth ventricular tumors whose precise cause remains elusive, but may be related to the surgical approach or injury to adjacent cerebellar structures. We present a small series of fourth ventricular tumors and our initial experience in using the telovelar approach for this surgery. METHODS: Twenty patients with fourth ventricular tumors were operated on using the microsurgical telovelar approach, sparing the cerebellar vermis. Data were collected prospectively for all patients with respect to the degree of resection achieved, complications and the incidence of posterior fossa syndrome. RESULTS: A complete resection was achieved on postoperative MRI in 70% of the patients. Residual disease <1.5 cm(3) remained in 15% and a further 15% had subtotal resection with >1.5 cm(3) of residual disease. Thirty percent had evidence of posterior fossa syndrome in the postoperative period, of which 84% had resolved at the last follow-up. Thirty percent of the patients developed symptomatic hydrocephalus requiring shunting. There were no new neurological deficits and no procedure-related deaths. CONCLUSION: The telovelar approach provides excellent access to tumors of the fourth ventricle with sparing of the vermis in children. The high incidence of cerebellar mutism in our patients confirms that this phenomenon is unlikely to be related to vermian injury and further study is recommended.

Complex orofacial movements and the disappearance of cerebellar mutism: report of five cases.

A syndrome of mutism and subsequent dysarthria occurs frequently in children after resection of a cerebellar tumour. The role of orofacial and speech motor control in this syndrome has not been studied systematically. We examined simple and complex orofacial movements during the mute phase and shortly after the resumption of speech in five children with mutism and subsequent dysarthria. The recovery of complex orofacial movements coincided with the disappearance of the mutism.