[Incidence of surgery for hydrocephalus in adults surveyed: same number afflicted by hydrocephalus as by multiple sclerosis].

The incidence of surgical treatment for adult hydrocephalus (older than 18 years) in Sweden from 1996 to 1998 was surveyed. The number of operations was 891 and the average incidence 3.36 operations per 100,000 inhabitants and year, varying regionally from 2.3 to 6.3. The mean age was 60 years (range 18-92), with no sex difference. Normal pressure hydrocephalus (47%) was most common, followed by communicating high pressure hydrocephalus (27%) and aqueductal stenosis (11%). 804 shunt operations (90%) and 67 ventriculostomies (7.5%) were performed, 2% were unclassified.