Long-term Survival Rates in U.S. Veterans Shunted for iNPH: A Focused Analysis of Radiological Predictors

Area of Science:

• Neurosurgery
• Neurology
• Geriatric Medicine

Background:

• Long-term survival data for idiopathic normal pressure hydrocephalus (iNPH) shunting in the U.S. is limited.
• The prognostic significance of ventriculomegaly markers for overall survival (OS) in iNPH patients is not well-established.

Purpose of the Study:

• To investigate long-term survival rates in U.S. veterans following iNPH shunting.
• To evaluate the prognostic value of preoperative ventriculomegaly markers, specifically Callosal angles (CAs), for OS in shunted iNPH patients.

Main Methods:

• Kaplan-Meier analysis was used to compare 10-year OS between shunted iNPH patients (n=154), suspected non-shunted iNPH patients (n=45), and age-/sex-matched controls.
• OS was modeled using eight preoperative CT-derived ventriculomegaly markers, with a focus on Callosal angles (CAs).

Main Results:

• The estimated 10-year OS for U.S. veterans shunted for iNPH was 39%, similar to international estimates.
• Shunted iNPH patients did not significantly differ in OS compared to controls (HR=1.24, p=0.14), while non-shunted patients had worse OS (HR=1.82, p=0.020).
• Higher preoperative CAs (>74°) in shunted patients predicted longer 10-year OS and a survival advantage over non-shunted patients.

Conclusions:

• Overall survival in U.S. veterans shunted for iNPH is comparable to international cohorts and matched controls.
• Higher preoperative CAs are associated with improved long-term survival post-shunting, indicating potential for better surgical selection.
• Targeted postoperative management for severe iNPH (low-CA) and improved surgical selection may enhance long-term survival in suspected iNPH.