Abigail McKenna1, Kirvani Buddhiraju1, Sanjiv Harikumar1, Ethan Richman1, Stephen Jaffee2, Jenna Li2, Jody Leonardo2
1Drexel University College of Medicine, 2Allegheny Health Network, Neuroscience Institute
Objective:
We present an analysis of the largest single-provider database of tap trials done for the evaluation of NPH.
Background:
Normal pressure hydrocephalus (NPH) is classified by neurodegenerative (nNPH), secondary (sNPH), or idiopathic (iNPH) etiologies with symptoms including gait changes, cognitive decline, and urinary incontinence. Cerebrospinal fluid (CSF) diversion via shunting is the mainstay of treatment, though response varies with etiology and presentation. Operative candidacy can be stratified using a lumbar tap trial (TT) to screen a patient’s response to CSF diversion.
Design/Methods:
A large sample retrospective analysis from January 1st, 2020 to December 30th, 2024 included 248 patients who underwent a TT. The protocol included pre-procedural gait evaluation by a neuro-physical therapist (timed walk (TW) and timed up-and-go (TUG)), cognitive assessments, and subjective bladder impairment. Patients then underwent a fluoroscopic-guided lumbar puncture, removing 30-50 mL of CSF. TW and TUG were reassessed immediately post-procedure and 24-hr post-procedure. A positive TT was defined by a reduction in TUG > 3.5 seconds, and a TW reduction > 20% with subjective symptomatic improvements.
Results:
NPH etiologies included n=59 nNPH, n=44 sNPH, and n=116 iNPH. 29 patients had mixed sNPH/nNPH. 237 patients (95.6%) completed the TT; 3 procedures were aborted and 8 patients lacked follow-up data. 36 patients reported transient headaches or low back pain, resolving conservatively. 86/237 (36.3%) had improvement in TUG (average 4.2 second reduction) and 75/237 (31.6%) in TW (average 6.2 second reduction). Subjective improvement occurred in gait 116/237 (49.8%), bladder 43/206 (21.1%), and cognition 50/209 (24.3%), defined by “yes”/“no”. 166 patients (70.0%) had positive tap trials and 116 (69.9%) underwent shunting.
Conclusions:
Combined with ambulatory biomarkers, cognitive function, and urinary control, the lumbar tap trial is a successful screening method for shunting patients with NPH.
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