The question is whether prenatal diagnosis of a congenital condition shortens the time to surgical intervention. The condition is one that is obvious at birth, but not necessarily in utero, and once diagnosed requires transfer to one of a handful of institutions that are capable of surgically intervening.
All data is retrospective.
The time interval starts with birth and ends with the initial surgical intervention. The categorical variable will be prenatal diagnosis status.
There are a handful of individuals for which we do not know the date of initial surgical intervention due to incomplete records (We do know that the event was reached, however).
I am having trouble deciding whether this situation is an appropriate application of survival analysis.