I was barely given any pre-op instructions today (no mention of an enema) so I'm wondering what my post-op diet is supposed to consist of? Only soft foods? High fiber? Low protein? I'm lactose intolerant so milk is out of the question. I did see that pediatric Boost is lactose free.
Any tips or suggestions?

Cagirl,
my pre-op diet instructions were just to not eat after midnight. As for post-op, you need to eat what you always eat with your fissure to keep the bm's soft and moving while your healing.

Post-op diet should be roughly the same as pre-op. Keep your stools soft and you'll be okay, i.e., boiled veggies + Miralax, whatever works for you.
For me personally, pre-op I was way freaked out about what the first few poops post-op would be like. Caused me a lot of anxiety. When it came time for the first poop (was the day after surgery), it actually wasn't too bad. Yes, it did hurt a little bit, but not as bad as an acute fissure. Not even close.
What's weird is that initially (first few days after LIS) I wasn't pooping very much at a time, and that was actually really annoying. I'd poop a couple times a day, and they'd occur without much drama, but every time it was just a few tiny turds :) I think it's because the anesthesia kind of messes up your system. So to force the issue, I actually started eating kind of junky foods to try to create bigger stools that would pass in fewer trips to the throne. Go figure, right?
Anyhow I think what I'm getting at here isn't so much to go and eat garbage after surgery. But it's more to listen to your body. Stick to your same regimen immediately after surgery and see how it goes. But be adaptable. If you find that your GI system is acting kind of funny, adjust your diet to try to change it.
And last but not least: if you feel like you need to take opiate painkillers after surgery, do it! Don't be afraid of constipation as long as you're taking Miralax or some other effective stool softener. Most people don't need painkillers for long but some (like me) did. Don't skimp on them because of fear of constipation, because trust me, Miralax conquers all :)

Oh yeah, and good luck tomorrow! LIS was my first surgery, and I know when I was in the operating room, it was a great comfort to think of all the others here who had gone through the same thing. We'll be thinking of you and waiting to hear back on how everything went, eh!