Long-term follow-up in idiopathic normal pressure hydrocephalus - towards a more comprehensive disease outcome.

Background: Idiopathic normal pressure hydrocephalus (iNPH) is characterized by a slowly progressive clinical triad of gait disorder, cognitive decline and urinary incontinence combined with ventricular dilation and normal mean intracranial pressure. We aimed to evaluate the 6-year follow-up after shunt implantation in patients with iNPH.

Methods: We retrospectively reviewed the data of all patients with iNPH treated with shunt surgery over a 6-year follow-up period. Outcomes were assessed using the Kiefer Scale and the NPH-Recovery Rate (NPH-RR). Secondarily, the number of steps needed for 180° turn as a measure of gait disturbance, the Montreal Cognitive Assessment (MoCA) score as a measure of cognitive decline and the urinary continence status of patients were recorded.

Results: A total of 165 patients (mean age 74.7 ± 7.4 years) were included in this study. The mean preoperative Kiefer Score was 7.3 ± 3.1, significantly higher than the Kiefer Score 6 months, 1, 2, 3, 4, 5 (p < .001) and 6 years (p = .006) after shunting procedure. The NPH-RR in the first 3 years after shunting procedure was greater than 5 and therefore representing a good clinical outcome. The number of steps for 180° turn decreased from 4.4 ± 1.9 preoperatively to 2.8 ± 1.6 postoperatively. 28 of 165 patients (17.0%) underwent MoCA testing both pre- and postoperatively, with nine patients (32.1%) showing significant improvement. The proportion of urinary incontinent patients decreased from 70.4% to 29.6%.

Conclusion: Patients with iNPH benefit significantly from shunt therapy up to 6 years postoperatively, with improvements noted among all components of the clinical triad.