VC placement in narrow ventricles requires accurate placement with simple means in an every-case routine. The suggested smartphone-assisted guide meets these criteria. Further data are planned to be collected in a prospective randomized study.

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Despite emerging knowledge of over 40 years, the postoperative results after shunt implantations in patients diagnosed for normal-pressure hydrocephalus (NPH) have not improved significantly in the last decade. For this reason, predictors have to be identified in order to preoperatively predict the course of disease. From 1982 to 2000, we examined in a prospective study 200 patients diagnosed for NPH. Of the patients who were surgically treated by a shunt implantation we could re-examine 155 (78%) in a mean time interval of 7 months after operation. The NPH was graduated according to the results of the intrathecal infusion test in an early state NPH (without brain atrophy) and late state NPH (with brain atrophy). In the study we focused our attention on the possible predictors: patient’s age, length of disease, clinical signs – like gait ataxia, dementia and bladder incontinence, etiology idiopathic/secondary as well as implanted valve type and the value of resistance to cerebrospinal fluid outflow. To measure the outcome we used the NPH recovery rate, as statistical test the χ² according to Pearson. In 80 patients with an early stage NPH (without cerebral atrophy) and a short course of disease (<1 year), slightly distinct dementia and an implanted Miethke Dual-Switch valve were significant predictors for a positive postoperative outcome. The outflow resistance measured in the intrathecal infusion test showed only a minimal relevance for the outcome. Those 75 patients with a late state NPH (with cerebral atrophy) had a better outcome when dementia was not present, the outflow resistance was >20 mm Hg·min/ml, the CSF tap test was positive and a Miethke Dual-Switch valve was implanted.

Since the beginning of 1995 the new hydrostatic dual-switch valve (DSV) was implanted in 35 adult patients with hydrocephalus of different etiology. 26 patients suffered from normotensive hydrocephalus (10 idiopathic and 16 symptomatic), and 9 patients from hypertensive hydrocephalus of various origin. The first 21 cases of this cohort were compared in a randomized study with a comparable group of 21 hydrocephalic patients who received a conventional differential-pressure (DP-) valve. The clinical status and CT were assessed prior to shunting, 14 days and 3 and 6 months after the operation. The reduction of ventricular size was evaluated by the measurement of the Evans Index. The CT follow-up in the DSV group was characterized by an only minimal (14) or only slight (16) reduction of ventricular size in the vast majority of cases. A comparison of 21 patients with a DSV and the patients with DP valves, evaluated by measuring the reduction of the Evans Index, revealed a distinctly higher percentage of significant regressions in the DP valve collective, without doubt due to chronic overdrainage. The overall clinical result of our 35 patients with a DSV was excellent and good in 31 patients, but the outcome seems to be more dependent on the preshunt damage of the brain than on hydrocephalic aspects. A neglegible incidence of subdural effusions in the DSV group compared to 11 cases in the DP valve collective reflects the ability of the DSV to prevent overdrainage. The capability of the DSV to maintain the IVP within physiological limits after shunting, especially in the upright position, is documented by a comparison with possible unphysiological IVP variations in other valve constructions, which depend on the level of implantation, subcutaneous pressure or CSF flow through the valve.

No abstract