I am writing to share my personal lessons learned so far as I try to heal. I was diagnosed with an AF eight weeks ago. Every person is different, but I'm sharing these observations, in case they may apply to anyone else's body. I've had relatively pain-free BMs for the last two weeks, and my colorectal surgeon says the fissure is healing and much smaller... after much sound and fury along the way to this point. Here are the three things that appear to have been crucial to making progress in my case.
Diet: go with soluble fiber rather than insoluble. Soluble fiber makes my stool gelatinous and soft. Insoluble fiber makes my stool higher in diameter. The patient education materials I got from my colorectal surgeon emphasized (very unfortunately) insoluble fiber, exactly the wrong kind. With help from my physical therapist, I switched to soluble fiber foods (beans, pears, oats) and noticed that bowel movements became less painful and lower risk in terms of re-tearing the AF.
Nifedipine: this ointment seems to work in reducing the extent of spasms. My CRS had me apply 0.2% four times daily on the outside and rim of my anus. It seems to help avoid spasms, increase blood flow, and allow healing to occur.
Physical therapy: my fissure may have been caused by improper use of my pelvic floor muscles over a period of decades. I used the external sphincter muscles to keep skin tags from old hemorrhoids inside my anus. With the help of therapists, I have been learning to relax the sphincter and instead stabilize with my left/right abdominal oblique muscles and diaphragm muscles. This seems to have taken some pressure off the rectum and AF, which in turn allowed the AF to be more free to heal.

Hi Prospero,
What do you mean by stabilize with abdominal muscles?
I've been reading up on pelvic floor therapy too.
That's great that you are healing!
Thank you for sharing your insights, very helpful.
-Tanya

Hi woi,
Thanks for the encouragement. We all need it. I'm very grateful to have found this website.
I get the impression that pelvic floor retraining is very customized, depending on a person's symptoms. I'll explain what I mean by "stabilize with abdominal muscles" in a moment. But first...
I'm a male. Pelvic floor stuff for a male might be different from being female.
Also, just a note about my underlying problem and theorized cause of the AF. I was straining for years using my sphincter muscles. I wasn't using my abdominal obliques and diapragm muscles, especially on the left side, when standing and sitting. It seems that these muscles somehow keep weight or pressure off my rectum. However, because I wasn't using them, it seems the tissue down in my rectum finally gave out and tore. After the AF was diagnosed, I had 10/10 pain when standing and sitting. I had very little insight into why. When I knelt with my left knee up, however, the pain went away. After weeks of working with physical therapists to try to get a handle on things, we realized that I was not using my left obliques and other muscles in the deep abdominal area (not talking about the sixpack muscles) when standing and sitting. When I started to gain conscious control of those muscles, the stress on my AF went down big time. My suspicion is that I took a lot of gravity weight off the AF, by stabilizing my core with those muscles.
Another cause of problems was using the sphincter muscles instead of having them be relaxed. I worked with the physical therapists to learn how to relax my pelvic floor muscles using biofeedback electrodes and scanner to measure muscle activity. By relaxing those muscles, I improved the ability of the surrounding tissue to heal, since too much muscle activity (e.g., spasms) reduced blood flow and therefore impedes healing.
It turned out that by using my abdominals, especially the obliques and muscles under my rib cage, I was much more able to keep my pelvic floor muscles relaxed. I suspect that relaxation helped with blood flow, and helped the nifedipine to do its job too, in keeping the muscles down there nice and relaxed and getting lots of blood supply.
Whether any of this applies to a woman's body, I don't know. However, if you use your sphincter a lot when you are not having a BM, I wonder if there might be opportunities for you to explore with a good, hands-on physical therapist.

Hey Prospero,
Thanks so much for going into detail. I don't think this applies to me except for my pelvic floor needing to relax.
I just finished reading a book by Amy Stein for that and am going to implement the stretches starting today.

How did you get hooked up with a physio therapist? Were you refered by your GP?
-Tanya

I was referred by my CRS.