I would definetly do the balloon dilation prior to surgery.
I've got an anal stricture and my gastro. dilates during my annual colonscopy and then every 6 months I get a "sigmoidoscopy" where he does the same thing.
My stricture is pretty bad, but the Versed (sp?) used during the procedure usually does the trick in terms of pain management. I also receive the Versed for the sig.
Does it help? Yes, a bit, not completely or I'd wouldn't have to do it every 6 months. But I'll take having to go in for a simple short out patient procedure every 6 months to surgery.