Whither preoperative shunts for posterior fossa tumours?

Some degree of hydrocephalus is present in almost all cases of medium to large posterior fossa tumours. The initial symptoms in such cases are usually due to the hydrocephalus and the consequent increased supratentorial pressure, and more often precede the symptoms primarily due to the local invasion and compression of the brain stem and cerebellum by a significant length of time. In our experience, based on 62 posterior fossa tumour operations, insertion of a cerebrospinal fluid (CSF) diverting shunt because of hydrocephalus makes the subsequent tumour excision more difficult and hazardous. The various problems presumed to be related to preoperative shunt surgery are discussed in this report. It is concluded that preoperative shunts for posterior fossa tumours are rarely indicated.