De or het snoeioperatie?

The correct Dutch article is:

de snoeioperatie

Rule Words ending in -tie and -sie: almost always de. See the rule

How to use snoeioperatie

the snoeioperatiede snoeioperatie
this snoeioperatiedeze snoeioperatie
that snoeioperatiedie snoeioperatie
our snoeioperatieonze snoeioperatie
your snoeioperatiejouw snoeioperatie
every snoeioperatieelke snoeioperatie
which snoeioperatie?welke snoeioperatie?
a big snoeioperatie / the big snoeioperatieeen grote snoeioperatie, de grote snoeioperatie