Tumour type and size are high risk factors for the syndrome of "cerebellar" mutism and subsequent dysarthria

Objective-"Cerebellar mutis" and subsequent dysarthria (MSD) is a documente d complication of posterior fossa surgery in children. In this prospective study the following risk factors for MSD were assessed: type, size and site of the tumour; hydrocephalus at presentation and after surgery, cerebellar incision site, postoperative infection, and cerebellar swelling. Methods-In a consecutive series of 42 children with a cerebellar tumour, sp eech and neuroradiological studies (CT and MRT) were systematically analyse d preoperatively and postoperatively. Speech was assessed using the Mayo Cl inic Lists and the severity of dysarthria using the Michigan rating scale. Results-Twelve children (29%) developed MSD postoperatively. The type of tu mour, midline localisation, and vermal incision were significant single ind ependent risk factors. In addition, an interdependency of possible risk fac tors (tumour>5 cm, medulloblastoma) was found. Conclusion-MSD often occurs after paediatric cerebellar tumour removal and is most likely after removal of a medulloblastoma with a maximum lesion dia meter>5 cm.