Lumboperitoneal Shunts for the Treatment of Idiopathic Normal Pressure Hydrocephalus: A Comparison of Small-Lumen Abdominal Catheters to Gravitational Add-On Valves in a Single Center

BACKGROUND: Treating idiopathic normal pressure hydrocephalus (iNPH) with lumboperitoneal shunts (LPSs) may cause cerebrospinal fluid (CSF) overdrainage. OBJECTIVE: To investigate whether LPSs, including gravitational “add-on” and programmable pressure valves (PPVs/+GVs), reduce complications and improve outcomes. METHODS: We compared PPVs/+small lumen abdominal catheters (SLs) to PPVs/+GVs using different opening pressures for supine and standing positions. We analyzed 115 patients with iNPH in 2 consequent cohorts: 48 patients receiving LPSs with PPVs/+SLs and 67 patients receiving LPSs with PPVs/+GVs. The modified Rankin Scale (mRS), Japan iNPH grading scale, Mini Mental State Examination, Frontal Assessment Battery, and CSF biomarkers were evaluated. RESULTS: Comparisons of postoperative clinical factors in 64 patients in the PPV/+SL and PPV/+GV groups using 1:1 propensity score matching revealed differences in the mean (±standard deviation) postoperative mRS (2.65 ± 1.07 vs 2.16 ± 1.02, P = .049) and gait disturbance scores (1.97 ± 1.03 vs 1.39 ± 0.92, P = .011). Thus, outcomes improved in the LPS group with the GV. Serious and nonserious adverse event rates for the PPV/+SL and PPV/+GV groups were 22.9% and 19.4% (P = .647) and 38% and 17.9% (P = .018), respectively, indicating higher rates of subdural collections for the PPV/+SL group. CONCLUSION: This is the first study to examine LPS treatment for iNPH using a GV in tandem with a PPV. Our results suggest that the CSF shunt flow volume is restricted in the standing position and maintained in the supine position, thus improving iNPH symptoms. This may reduce intracranial CSF hypotension-related complications.