Accuracy and safety of 1-day external lumbar drainage of CSF for shunt selection in patients with idiopathic normal pressure hydrocephalus

Abstract

OBJECTIVEThree to five days of external lumbar drainage (ELD) of CSF is a test for ventriculoperitoneal shunt (VPS) selection in idiopathic normal pressure hydrocephalus (iNPH). The accuracy and complication rates of a shorter (1-day) ELD procedure were analyzed.METHODSData of patients with iNPH who underwent 1-day ELD to be selected to undergo VPS placement with a programmable valve in the period from 2005 to 2015 were reviewed. Patients experiencing VPS complications, valve malfunctioning, or with less than 1 year of follow-up were excluded. The ability of 1-day ELD to predict VPS outcome at 1- and 12-month follow-up was assessed by calculating sensitivity, specificity, and positive and negative predictive values.RESULTSOf 93 patients who underwent 1-day ELD, 3 did not complete the procedure. Of the remaining 90 patients, 2 experienced transient nerve root irritation. Twenty-four patients had negative test outcomes and 66 had positive test outcomes. Nine negative-outcome patients had intraprocedural headache, which showed 37.5% sensitivity (95% confidence interval [CI] 19.5%–59.2%) and 100% specificity (95% CI 93.1%–100%) as predictors of negative 1-day ELD outcome. Sixty-eight patients (6 with negative and 62 with positive outcomes) underwent VPS insertion, which was successful in 0 and 58 patients, respectively, at 1-month follow-up. Test sensitivity and specificity in predicting surgical outcome at 1-month follow-up were 100% (95% CI 92.3%–100%) and 60% (95% CI 27.4%–86.3%), respectively, with 94.1% accuracy (95% CI 85.6–98.4%). Among the 1-day ELD–positive patients, 2 showed no clinical benefit at 12 months follow-up. Test sensitivity and specificity in predicting surgical outcome at 12-month follow-up was 100% (95% CI 92.5%–100%) and 75.0% (95% CI 35.6%–95.5%), respectively, with 97.1% (95% CI 89.8%–99.6%) accuracy.CONCLUSIONSOne-day ELD is a reliable tool in iNPH management, with low complication risk and short trial duration. The test is very consistent in predicting who will have a positive outcome with VPS placement, given the high chance of successful outcome at 1- and 12-month follow-up; negative-outcome patients have a high risk of unsuccessful surgery. Intraprocedural headache is prognostic of 1-day ELD negative outcome.

Aqueductal CSF stroke volume measurements may drive management of shunted idiopathic normal pressure hydrocephalus patients

“…Upon confirmation from future studies with a larger population size and more accurate definition of outcomes (which would lead to greater statistical power and thus clearer results), the ∆SV window may permit, by either up or down OPV regulation leading to small ∆SV, to optimize the clinical course of shunted patients and extend the spectrum of patients who may benefit from shunting. The availability of an accurate prognostic test 7 , 14 , to exclude from surgery non-hydrocephalic patients, and a range of ∆SV values within which the clinical outcome is maximized, may provide relief to patients regardless of their degree of brain atrophy. Stratification of patients according to their intracranial hydrodynamics, hence with different optimal ∆SV windows, might allow a better outcome within each subgroup.…”

“…Patients provided consent to use their clinical data for research purposes. iNPH management protocols were reported 14 . Informed consent to clinical procedures was obtained from all patients.…”

“…Gait disorders were evaluated by a gait scale graded into 4 categories: normal gait (grade 0); discrete imbalance when turning with short steps, widened base, and occasional falling (grade 1); frequent falls and aid needed for ambulation (grade 2); and impossible gait (grade 3) 12 . Patients were selected for ventriculoperitoneal shunt placement on the basis of improvement after lumbar drainage 14 . A gain by ≥ 2 points combining the urinary and gait scales, or a gain by one point in urinary or gait scales and by ≥ 3 points on the MMSE was considered an improvement.…”

Clinical predictors of shunt response in the diagnosis and treatment of idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis

“…Eight studies used an ELD for the prediction of SR using different response criteria for ELD (Table 4) [7,8,17,19,35,36,47,69].…”

Evaluating the Cerebrospinal Fluid Tap Test With the Hellström iNPH Scale for Patients With Idiopathic Normal Pressure Hydrocephalus – a Retrospective Cohort Study of 132 Patients

“…An elevated resistance has been suggested as a predictor of a positive outcome of shunt surgery (13), but this test has been reported to have low sensitivity (12,14,15). External lumbar drainage of CSF (ELD) for one to several days has a high positive predictive value but requires hospital admission and has an inherent risk for complications (16)(17)(18). Less invasive and commonly used is the cerebrospinal tap test (CSF TT), which involves a lumbar puncture (LP) with removal of 30-50 ml CSF and clinical evaluation before and after the LP (19)(20)(21)(22).…”