I wish you the very best of luck with your surgery! You should certainly tell the hospital about your incontinence issue which you use diapers to manage. You say that your surgery will be done on an outpatient basis, which means that, unless some complication arises, you won't be in hospital overnigh. That means you probably won't be having a hospital staff member changing your diaper more than maybe once. Nevertheless, assuming that you use high-capacity diapers on a regular basis, you should take a couple of your own diapers with you. Hospitals generally buy low quality diapers that won't last you more than two or three hours.