# The diagnostic value of the lumbar infusion test to predict symptomatic improvement after shunting for normal pressure hydrocephalus. A meta-analysis

## TL;DR

This study evaluates how well the Lumbar Infusion Test predicts which patients with normal pressure hydrocephalus will benefit from shunt surgery.

## Contribution

The study provides a meta-analysis of the Lumbar Infusion Test's diagnostic accuracy for predicting shunt responsiveness in normal pressure hydrocephalus.

## Key findings

- The Lumbar Infusion Test has poor negative predictive value for predicting non-response to shunting.
- Sensitivity and specificity of the test vary with different resistance to outflow cut-off values.
- The test cannot reliably exclude patients from shunt implantation based on current parameters.

## Abstract

The aim of this meta-analysis is to determine the diagnostic value of the Lumbar Infusion Test (LIT) to differentiate between patients suffering from normal pressure hydrocephalus who will benefit from CSF shunting and those who will not.

A systematic search was performed in Ovid MEDLINE to identify RCTs or observational studies that evaluated LIT for predicting shunt responsiveness. Sensitivity and specificity values were pooled and Bayesian meta-analysis was performed.

The Resistance to outflow (Rout) sensitivity was 76.9%; 81.6% and 36.6% for a Rout cut off of respectively 12, 14 and 18 mmHg/ml/min. Specificity rose with higher Rout cut off and was 34.0%; 37.2% and 78.0% for a cut off of respectively 12, 14 and 18 mmHg/ml/min. The negative predictive value was low for each cut off and was at most 33.3%.

The LIT proves poor negative predictive value and appears an ineffective tool in the prediction of non-response to a shunting procedure. Therefore, in its present form and based on its current parameters, it cannot be used as a test to exclude patients from shunt implantation.

The online version contains supplementary material available at 10.1007/s00701-025-06591-8.