Posterior fossa syndrome: Identifiable risk factors and irreversible complications

Cerebellar mutism was first described by Rekate et at. in 1985 as a transie nt condition which occurs after posterior fossa operations in children. Pos terior fossa syndrome (PFS) and cerebellar mutism are often used interchang eably in the literature. In our experience, we found cerebellar mutism to b e a reversible component of a persistent neurologic syndrome. The cause and identifiable risk factors have not been dearly elucidated in the literatur e. To further characterize PFS, we reviewed 253 children with posterior fos sa tumors who underwent surgical resection. We documented 20 cases of PFS ( 8%), 12 males and 8 females. Age ranged from 1.5 to 13 years (mean = 6.5). Of the 20, 16 were medulloblastoma, 3 ependymoma and 1 astrocytoma. There w as a 21% incidence (16/76) of PFS in medulloblastoma of the posterior fossa . The incidence for ependymoma was 13% (3/24) and 1% (1/102) for astrocytom a. All 20 cases (100%) had brainstem involvement by the tumor, The most fre quent postoperative findings included mutism, ataxia, 6th and 7th nerve pal sies and hemiparesis. Mutism had a latency range of 1-7 days (mean = 1.7) a nd a duration of 6-365 days (mean = 69.2, median = 35). Although mutism res olved in all cases, the remaining neurologic complications which characteri zed our findings of PFS were rarely reversible. We describe potential risk factors for developing PFS after surgery with hopes of making neurosurgeons more aware of potential problems following the removal of lesions in this area. Early recognition of PFS would further promote patient and family und erstanding and coping with this syndrome. Copyright (C) 1999 S. Karger AG, Basel.