Prognostic Factors in Idiopathic Normal Pressure Hydrocephalus Patients after Ventriculo-Peritoneal Shunt: Results from a Single-Institution Observational Cohort Study with Long Term Follow-Up

OBJECTIVE:The aim of this study is to investigate long-term prognostic factors and clinical outcomes in patients with idiopathic normal pressure hydrocephalus (iNPH) treated with ventriculo-peritoneal shunt (VPS). METHODS:This single-center retrospective observational study of prospectively collected data included patients with probable iNPH treated with VPS surgery. All patients underwent complete preoperative assessment, including past medical history and neurological examination, dynamic cerebrospinal fluid (CSF) flow brain magnetic resonance imaging (MRI), and preoperative CSF samplings. NPH-consistent brain MRI findings and favorable responses to CSF subtraction tests were the main factors considered for VPS surgery eligibility. All patients were subsequently followed up every six to twelve months (mean follow-up time 40 months, minimum to maximum interval 6-150 months). RESULTS:A total of 238 patients with a diagnosis of probable iNPH treated with VPS were enrolled. Age, comorbidities, and response to CSF samplings were not significantly associated with a better long-term outcome after VPS surgery. The results of our retrospective analysis demonstrated a statistically significant association between the presence of preoperative aqueductal CSF flow acceleration on dynamic brain MRI and neurological outcomes at 12 and 18 months after VPS surgery. CONCLUSIONS:Long-term outcomes of iNPH patients treated with VPS surgery do not appear to be directly influenced by preoperative comorbidities, age, or responses to CSF samplings. Alterations in preoperative brain MRI CSF dynamics were found to be related to long-term outcomes following VPS surgery, highlighting the role of radiological assessment as a prognostic factor in patients deemed suitable candidates for VPS surgery.