CSF tap test - Obsolete or appropriate test for predicting shunt responsiveness? A systemic review

Area of Science:

• Neurosurgery
• Neurology
• Diagnostic Testing

Background:

• Accurate diagnosis of normal pressure hydrocephalus (NPH) and identification of patients who will benefit from shunt surgery remain challenging.
• The cerebrospinal fluid tap test (CSF-TT) is utilized to enhance predictive value in selecting NPH patients for shunting.

Purpose of the Study:

• To systematically review the literature evaluating the effect of the CSF-TT on main symptom outcomes.
• To assess the validity parameters of the CSF-TT in screening patients suitable for shunting.

Main Methods:

• A systematic literature search was conducted in February 2015.
• Keywords included: normal pressure hydrocephalus, idiopathic normotensive hydrocephalus, shunt operation, CSF tap test, predictive value, and validity.
• Eight articles directly addressing the topic were retrieved.

Main Results:

• The CSF-TT demonstrated a high positive predictive value (92%) but a low negative predictive value (37%).
• Specificity was high (75%), while sensitivity was average (58%).
• The overall accuracy of the CSF-TT was 62%.

Conclusions:

• The systematic review did not yield unambiguous validity for the CSF-TT in screening NPH patients for shunting.
• A positive CSF-TT response is highly reliable for patient inclusion in shunting.
• A negative CSF-TT response is not reliably indicative of ineligibility for shunting, necessitating further research.