Preoperative factors associated with shunt responsiveness in patients with idiopathic normal-pressure hydrocephalus

We aimed to evaluate a possible association between preoperative factors (disease duration and vascular risk factors) and shunt responsiveness in patients with idiopathic normal-pressure hydrocephalus (iNPH).

We conducted a retrospective observational study in a high-volume center for iNPH treatment in Japan and reviewed the clinical data of 107 consecutive patients with probable iNPH who underwent shunt surgery between January 1, 2018, and August 31, 2019, and were followed up for at least 12 months after surgery. Preoperatively, these patients underwent the timed up-and-go test (TUG) and Mini-Mental State Examination (MMSE); moreover, follow-up evaluations were performed 12 months postoperatively, at which TUG and MMSE scores were used as metrics for shunt responsiveness assessment. The degree of shunt responsiveness was regressed to several preoperative factors, including preoperative TUG and MMSE scores, vascular risk factors, and duration from iNPH onset to shunt surgery, to evaluate which preoperative factors may be predictive of shunt responsiveness.

In multivariate regression analysis, there was no statistically significant association between the presence of preoperative vascular risk factors and the postoperative TUG or MMSE score 12 months after shunt surgery. Meanwhile, preoperative history of ischemic stroke and a longer duration from iNPH onset to surgery were significantly associated with poorer shunt responsiveness in terms of MMSE and TUG scores.

The current study suggested the potential involvement of stroke history and disease duration with the 1-year prognosis of iNPH after shunt surgery, of which validity needs to be corroborated in further studies.