Abstract
Background
Cerebellar mutism syndrome (CMS) is a postoperative syndrome of decreased speech seen
in children associated with neurobehavioral abnormalities, the incidence of which
is up to 40%.
Objectives
To evaluate pediatric patients with posterior fossa tumors for incidence, clinical
characteristics, pathophysiology, risk factors, and neuroradiographic features of
this syndrome.
Materials and Methods
The study included 60 pediatric patients with a posterior fossa tumor who underwent
surgery by a telovelar approach. Detailed pre- and postoperative clinical and radiological
evaluations were done. Patients with CMS were analyzed and compared with those without
mutism to find risk factors for CMS. The presentation and characteristics of cerebellar
mutism were studied along with the following risk factors:
Clinical—age, sex, cranial nerve deficit, and adjuvant treatment.
Radiological—tumor location, hydrocephalus, brainstem invasion, extent of tumor resection,
peduncular and brainstem edema, and atrophy of posterior fossa structures.
Pathological—histopathology of tumor.
The preoperative, immediate postoperative, and 1-year postoperative imaging results
were reviewed to assess the neuroradiographic features in the two groups.
Results
The incidence of this syndrome was 20%. The mutism was accompanied by some neurobehavioral
abnormalities (p -value = 0.05). The most significant finding was the presence of a period of cerebellar
dysarthria after the resolution of the muteness (p -value < 0.001) in all cases. Brainstem and related structures' involvement was the
most significant risk factor (p -value = 0.03). The presence of brainstem and peduncular edema in the immediate postoperative
period (p -value = 0.04) and gross atrophy of posterior fossa structures at 1 year (p -value = 0.01) showed significance toward the development of CMS. There was delayed
neurological recovery in patients with CMS with a poor Glasgow Outcome Score at 1
year of follow-up.
Conclusion
The clinical presentation of this syndrome in context with neuroradiographic features
suggests that it results from transient impairment of the afferent and/or efferent
pathways of dentate nuclei that are involved in initiating complex volitional movements
and are associated with brainstem involvement of tumor and poor functional outcome.
Keywords mutism - neurobehavioral - dysarthria - posterior fossa tumors in children - posterior
fossa syndrome
