Predictors of Outcome in Patients with Normal-Pressure Hydrocephalus

Abstract

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.

Features of gait most responsive to tap test in normal pressure hydrocephalus

“…The gait disturbance is typically the most prominent clinical feature of iNPH and is often the first symptom to develop [2,3]. Dramatic gait improvement can be achieved in some patients with the placement of a shunt; [4,5] however, the procedure can be associated with as much as 50% morbidity, including permanent neurological deficits, intracerebral hemorrhage, subdural hemorrhage, meningeal infection, as well as death [6][7][8][9]. Given the potential risk associated with this intervention, there is a need for improved patient selection criteria for shunt surgery.…”

Differences in Microstructural Alterations of the Hippocampus in Alzheimer Disease and Idiopathic Normal Pressure Hydrocephalus: A Diffusion Tensor Imaging Study

“…Greater improvements with shunt surgery would be expected in the early stage when the memory deficit is mild or absent. 11 However, most iNPH cases are diagnosed among patients older than 60 years of age, who also have an increased risk for AD; and in elderly patients with dementia and dilated ventricles, it is often difficult to differentiate iNPH from AD with visual evaluation by using MR imaging.…”

The impact of nutritional status on the outcome of Indian patients undergoing neurosurgical shunt surgery

“…Regardless of aetiology, shunt insertion (venticulo-peritoneal 17 or lumbo-peritoneal 16 ) is still the most common form of treatment for hydrocephalus. Despite improved shunt valve technology and surgical techniques, the treatment of hydrocephalus is still, however, associated with unsatisfactory outcomes 17,18 .Several risk factors have been identified for poor outcome, including demographic variables, aetiology, associated pathology and timing of the shunt 18 -20 . Because of associated vomiting, altered sensorium and chronic infections such as tuberculosis, a large number of these patients are expected to be undernourished 21 .…”

“…Regardless of aetiology, shunt insertion (venticulo-peritoneal 17 or lumbo-peritoneal 16 ) is still the most common form of treatment for hydrocephalus. Despite improved shunt valve technology and surgical techniques, the treatment of hydrocephalus is still, however, associated with unsatisfactory outcomes 17,18 .…”