Introduction: Idiopathic normal pressure hydrocephalus (iNPH) is characterized by gait deterioration, cognitive disturbances, and urinary incontinence. Gait deficits pose safety hazards due to frequent falls, yet objective assessments of gait improvement following ventriculoperitoneal shunt (VPS) placement are limited. The present study aims to assess objective improvement in gait parameters following VPS placement for iNPH.
Methods: All patients treated with VPS for iNPH by the senior author at a single tertiary care center between December 2017 and January 2023 were retrospectively reviewed. Patients who underwent detailed motion analysis testing preoperatively and at greater than one follow-up visit were included. Analyzed parameters included: gait velocity, gait cadence, stride length, stride width, gait stability ratio, total support, and single support. Time-dependent mixed effects linear (LME) and generalized additive models (GAMM) were utilized to model short-term and longitudinal gait parameter changes, respectively.
Results: A total of 212 patients who underwent VPS for iNPH were included with a total of 747 gait analyses performed at median last gait analysis follow-up time of 12.0 months. Median age was 75.2 years with 64.6% male. Statistically significant changes in all gait parameter values were noted between preoperative and first postoperative follow-up within 3 months (paired Wilcoxon p< 0.001) with a statistically significant majority of patients experiencing improvement (binominal p< 0.0001). Longitudinal analyses utilizing GAMM disclosed increased gait velocity, single support, and stride length with decreased stability ratio, step width, and total support at early timepoints with a plateau achieved around 6 months.
Conclusion : Detailed gait analysis demonstrated significant improvements in objective ambulation metrics following VPS in iNPH patients, particularly in gait velocity, stride length, and gait stability ratio. Most patients maintained marked improvement from baseline at last follow-up, though a plateau of the benefit was achieved with longer follow-up.
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