Well, Ashely's surgery was emergency (as in he was acting fine one day, the next he was crying and obviously in pain), so I don't know if it would be the same if he had been caught ealier. Ashely spent 1 night at the ER vet where he had the surgery and spent 3 additional days at our regular vet where he was on IV fluids & had a catheter (sp?) in addition to pain killers. This was a few years ago so I don't remember the specifics, but he was on strict rest for 2 weeks following the operation. After a few days he was feeling much better and we had a hard time keeping him calm, but I would think it would depend on the cat. Talk to your vet about the severity of the crystals and what they recommend. I hope your kitty is ok soon.
IVD is a good food, I don't know if the ingredients are anywhere online yet, but you could e-mail the company and ask:http://www.vetshow.com/exhibit/ivd/
Or, if you don't mind waiting, this site puts out pet food reviews and IVD is on their soon to come list:http://www.greatgoldens.com/catcomp.htm