I know it's easy to worry after searching Google and reading scary procedures. What I think might be helpful is to discuss your concerns/fears with your surgeon or care team for the procedure. I've always found it helpful to talk with them before the procedure when I had a worry or concern. Here is some information on NPH treatment that I hope helps some.

"A commonly used treatment for NPH is surgery to place a tube, called a shunt, into the brain to drain the excess fluid. The shunt is usually inserted into a ventricle in the brain and then passed under your skin from your head through your neck and chest to your abdomen."
-- Normal Pressure Hydrocephalus: https://www.hopkinsmedicine.org/health/conditions-and-diseases/hydrocephalus/normal-pressure-hydrocephalus