That most patients undergoing a big surgery will have most of the following and it's okay... 1) Fever 2) Pain 3) Trouble Peeing and Pooping 4) Itchyness 5) Minor Lung Issues (atelectisis, effusions, etc) 6) Nausea 7) And a bit of a breakdown at some point.
I work in Pediatric Surgery, lots of Ortho. We let 8-10 hours go by and most kids use most of the time. The longest I'll let them go is 12. Perhaps the reason why this seems more than most posts is how traumtic something like cathing is for a kid. Most of the time if they need the cath, they'll be begging for it by the time it's inserted.
Something like Operation Smile (cleft lips and palates) and Operation Rainbow (orthopedics) may be what you're looking for. Op. Smile missions are usually 1-2 weeks and cost the volunteer about $500, much less than other programs. Op. Rainbow, I'm not as sure about..