In general, the LIS surgeries that people get aren't meant to fix the fissures. They just loosen up the sphincter muscle so that the fissure has the space it needs to heal.
I'm sorry to hear about the fistula's. That sounds so painful and I hear the surgery is actually worse than the one I just had. I live alone, too. Its really scary around things like this.
I don't know if this applies to you, but we've had a couple people around here who have had surgery, thought that things weren't healing down there when really, they were healing just fine. The on-going problem was with neuropathic pain. (That's a pain that is just a problem with the nerves and is not linked to any other physical problem.)