Hi Matt - the Rudd clinic does require a referral from a doctor, but they can usually see you in about two weeks, as opposed to six months or so for a specialist affliated with a hospital. I got my fissure treated at the Rudd clinic. They will likely start you off with Diltiazem before they consider an LIS.
I don't want to alarm you, but I think you should know that they do the LIS surgery with no general anesthesia or even any kind of sedation - so you will be awake for it. I had a horrible experience with Dr. McKenna - he was extremely rough and impatient and didn't believe in pain management. Genevieve didn't have a great experience, but her fissure did heal eventually (I think she had other problems too). Redcharger and Adam, however, had much better experiences. Redcharger started with Dr. McKenna, but then switched to a different doctor at the Rudd clinic because he also found Dr. McKenna too rough. He just call the Rudd clinic and asked to be assigned a different doctor, and that worked out well for him. Adam had an abscess and a fistula taken care of at Rudd, and did quite well. I've pasted links to all of our posts below. I think the trick is to make sure you get a good doctor at that clinic, and understand that you will not be put to sleep for the procedure. My post is really horrifying, because Dr. McKenna was really nasty - but I will say that my fissure healed in about two to three weeks. I think Redcharger took some pain killers before his surgery - but I'm not sure. You'll want to read his posts pretty carefully. Please don't let my post freak you out too much. I had a particularly awful experience because Dr. McKenna is not gentle at all. But things might go better for you there.
I hope your appointment went very well today. :D
Here are the links to the posts:
Redcharger:
http://anal-fissure.org/t3156-my-lis-surgery-and-post-op-experience#61355
http://anal-fissure.org/t2960p60-pain-seems-unbareable#60065
Adam:
http://anal-fissure.org/t3141p120-wow-just-found-out-i-had-an-abcess-and-fistula-and-had-surg#64783
Genevieve:
http://anal-fissure.org/t45-genevieve?highlight=rudd
My experience:
http://anal-fissure.org/t2935-its-done-and-i-survived