gms | German Medical Science

The policy to indicate treatment in chronic hydrocephalus is still confusing. To evaluate the value of the resistance to outflow (ROF) and in contrast to that the influence of typical Co-morbidity in elderly we performed a prospective study.

From 1997 - 2003 in 125 patients with chronic hydrocephalus a dynamic infusion test was performed. In all patients a meticulous search of the medical history was performed. The types of co-morbidity were valued with 1 - 3 points and the sum of all points represented the general risk factor of co-morbidity (GRC) of each patient. The indication for shunt surgery based on ROF. All patients received a gravitational valve and were followed-up regularly. The clinical state pre- and postoperatively was assessed using the Homburger-Hydrocephalus Scale (HHS). All statistics were done at a significance level of 5%.

The mean follow-up was 46 ± 16 months. 2/3 of the patients suffered from a normal pressure hydrocephalus, the others from a non-communicating hydrocephalus. About 80% of the patients made a good or excellent recovery, while 12% were non-responder. Using Pearson`s Correlation coefficient we could not establish any correlation between ROF and outcome. However when using a CHI-square test, a critical value of 23 mm Hg x ml / min may be found separating favourable (good or excellent) and not favourable outcome. In contrast to the weak correlation between ROF and outcome, the predictive value of GRC was highly significant. Pearson's correlation coefficient indicated a strong negative influence of the co-morbidity on the outcome.

While ROF was not found to be predictive for outcome, the newly created GCR allowed a clear judgement of the probable benefit after shunting. At a margin of 23 mm Hg x ml / min ROF may be used to separate patients with favourable and unfavourable outcome. The strategy of shunt indication should consider co-morbidity.