Surgical treatment of idiopathic hydrocephalus in elderly patients.

We studied 45 adult patients with idiopathic hydrocephalus who had undergone a shunting procedure at the Mayo Clinic during a 16-year period. The follow-up period extended up to 157 months. Thirty-four of the 45 patients (75%) improved at some time after the operation, and 19 (42%) experienced continuous improvement. The median duration of improvement was 24 months. Patients who had symptoms for less than 2 years were most likely to improve. CT played an important role in the diagnosis and follow-up, but ventricular size or degree of atrophy did not correlate with response.