I realize (after I posted) your question was about a certain procedure. My advice is just about hospital life. Hope it helps.
My baby girl is 9 mths old and has had 4 surgeries. She's shown me that babies are very strong. My husband and I took shifts at the hospital. He was there at night and I stayed with her during the day. My advice would be to ask questions, pay attention to meds the nurse is giving your baby. Nurses change every 12 hrs so it's helpful to visit with them and make sure everyone is on track with the proper care for your baby. Find out when the doctors make daily rounds so you can be there to get their update and ask any questions you may have.
Right after surgery the nurse would try to figure out the proper amount of pain meds and most start slowly. They may ask you you're opinion on the sound of his cry, to help figure out what he needs. The first day was the hardest but it passes quickly.
I'm not sure how long your baby will be in the hospital but I liked using those round plastic colored links and connecting a strand across the crib. From those I could attach small toys that jingle, just something entertaining to catch his attention.
Now for you, bring snacks, magazines, some type of entertainment. Don't be afraid to ask questions. Know that you can always request to speak to the doctor. There's always a Charge Nurse on duty you can speak to if have any concerns regarding your child's care.
The first day you may feel overwhelmed, but time passes quickly and you're baby will be better before you know it.