My mom has a brain shunt under her scalp, its clogged and will be cleaned out on tuesday?

( god willing) my mom is 91 yrs old,and kind of frail but not concidered in grave condition.this procceedure takes 15 to 20 minutes to finish barring trouble,i need some expert advice here do they perform this under general anesthesia or local? the last surgery my mom had was to remove a plate from her knee which was infected,that was done under general, and that was done on sept 29th,mom is a trooper and a fighter,whats the general outlook for a patient of this age and health status which is fair.