When is a shunt no longer necessary? An investigation of 300 patients with hydrocephalus and myelomeningocele: 11-22 year follow up.

Three hundred consecutive patients treated with a shunt for hydrocephalus associated with open spina bifida were followed for a period ranging from 11 to 22 years with a view to answering the question: How long is a shunt necessary? At most, in 51 patients (17%) the shunt was no longer functioning and was not causing any trouble. It is possible that many of these will still develop problems of raised intracranial pressure and their shunt would have to be revised, or reinserted. In fact, this occurred in 14 patients who had a shunt without revision for 10 to 15 years before trouble started and the shunt had to be revised. It is concluded that it is unsafe to advise parents and patients that a shunt is no longer necessary, simply because a long time has elapsed without revision or because the shunt may be very short on X-ray or had been disconnected, or even removed. Nevertheless, there is a large proportion of individuals who, after a lapse of 10 years without revision, may well never require further procedures.