Introduction: Frailty, which is characterized by diminished physiological reserve and increased vulnerability to insult, is common in the idiopathic normal pressure hydrocephalus (iNPH) population. The degree to which frailty influences objective gait parameters in iNPH patients before and after ventriculoperitoneal shunting (VPS) is unknown. We sought to interrogate the association of frailty on gait outcomes following ventriculoperitoneal shunting (VPS) for iNPH.
Methods: A prospectively maintained database at a single tertiary care center was retrospectively reviewed for all patients undergoing VPS for iNPH with preoperative videographic gait analysis between October 2018 and May 2024. Gait parameters included cadence, gait velocity, single support, stability ratio, step width, stride length, and total support. Patients were stratified by preoperative modified 5-item frailty index (mFI) into non-frail (mFI-0), pre-frail (mFI-1), and frail (mFI-2+) groups.
Results: Of the 242 patients that were included, 60 (24.8%) were classified preoperatively as non-frail (mFI-0), 109 (45%) were pre-frail (mFI-1), and 73 (30.2%) were frail (mFI-2+), with no difference in age distributions across groups. A total of 844 gait analyses were performed with a median of three per patient and median latest follow-up time of 12.2 months. Baseline preoperative gait parameters varied significantly across mFI groups. However, the degree of change in gait parameters between preoperative and first postoperative gait assessments did not differ across mFI groups with most patients exhibiting improvement. Mixed effect models and estimated marginal means disclosed heterogenous effects of mFI and time on longitudinal changes in gait parameters.
Conclusion : Frailty was associated with lower baseline gait performance across several objective parameters, but most patients exhibited improvement at first postoperative follow-up with no difference in degree of change by frailty group. Furthermore, patients exhibited longitudinal and durable improvement in gait irrespective of frailty group, though the degree of improvement in certain gait parameters were significantly different according to preoperative mFI at one year postoperatively. Nevertheless, both pre-frail and frail iNPH patients exhibited improvement in gait after VPS.
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