Extended lumbar drainage in idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis of diagnostic test accuracy

Abstract

Background: When appropriately selected, a high proportion of patients with suspected idiopathic normal pressure hydrocephalus (iNPH) will respond to cerebrospinal fluid diversion with a shunt. Extended lumbar drainage (ELD) is regarded as the most accurate test for this condition, however, varying estimates of its accuracy are found in the current literature. Here, we review the literature in order to provide summary estimates of sensitivity, specificity, positive-and negative predictive value for this test through meta-analysis of suitably rigorous studies.Methods: Studies involving a population of NPH patients with predominantly idiopathic aetiology (>80%) in which the intention of the study was to shunt patients regardless of the outcome of ELD were included in the review. Various literature databases were searched to identify diagnostic test accuracy studies addressing ELD in the diagnosis of iNPH. Those studies passing screening and eligibility were assessed using the QUADAS-2 tool and data extracted for bivariate random effects meta-analysis.Results: Four small studies were identified. They showed disparate results concerning diagnostic test accuracy. The summary estimates for sensitivity and specificity were 94% (CI 41-100%) and 85% (CI 33-100%), respectively. The summary estimates of positive and negative predictive value were both 90% (CIs 65-100% and 48-100%, respectively). Conclusion: Large, rigorous studies addressing the diagnostic accuracy of ELD are lacking, and little robust evidence exists to support the use of ELD in diagnostic algorithms for iNPH. Therefore, a large cohort study, or ideally an RCT, is needed to determine best practice in selecting patients for shunt surgery.

Normal pressure hydrocephalus, or Hakim syndrome: review and update

“…There is a paucity of data regarding the sensitivity and specificity of ELD and HVLP in predicting shunt responsiveness, because most studies do not shunt patients who do not improve clinically after temporary CSF diversion. A recent meta-analysis of ELD as a diagnostic test for HS found varying results [33]. The investigators found only four small studies in which patients (n=84) having ELD underwent shunt surgery regardless of the outcome.…”

Diagnosis and treatment for normal pressure hydrocephalus

“…The advance of brain imaging could help detect secondary structural lesions, which exhibit a clinically similar presentation [ 12 ]. Even extended lumbar drainage use provides a better prognostic value for testing the diagnosis of iNPH, preoperative evaluation considering clinical symptoms, radiological findings, CSF biomarkers of iNPH, and neurophysiological signatures may ensure a higher effectiveness of shunt surgery [ 49 50 ].…”

Idiopathic normal pressure hydrocephalus: historical context and a contemporary guide

“…Meta-analyses have subsequently confirmed that the CSF tap test has a high positive predictive value and that external lumbar drainage also has a high specificity (~85% with wide confidence intervals) but there is no perfect predictive test for shunt responsiveness 24 25…”