The Role of Third Ventriculostomy in Previously Shunted Hydrocephalus

Summary

The problem of third ventriculostomy is that exact preoperative prediction of CSF outflow resistance is not possible [1]. This is of even more importance in patients with previously shunted noncommunicating hydrocephalus who present with shunt malfunction.

We describe the course of two patients who received a third ventriculostomy after malfunction/infection of a shunt. Both outcomes were satisfying, proving that CSF absorption had remained intact even years after shunting. However, one patient needed some time for adaptation: the third ventriculostomy with simultaneous shunt explantation was followed by 2 days of apparently increased ICP before the CSF outflow had completely adapted. In such cases, preoperative CSF absorption studies would have shown an elevated CSF outflow resistance. Preoperative dynamic CSF studies are not reliable in predicting whether CSF resorption will normalize under normal CSF load of the subarachnoid space.