In the past I have never taken the time to go back to a forum after my problem has been resolved, be it health related or otherwise. But this issue caused me so much pain, anxiety and feelings of despair that I thought my experience could be helpful to others.
I suffered the pain of a fissure for over 4 months. Every morning my bowel movement would lead to spasms of the internal sphincter, and severe pain that lasted most of the day. The fissure got infected and resulted in an abscess (puss formation under the skin) which burst one day at work. The abscess also caused a fistula (tunnel from where the abscess burst outside on my skin into the anal canal. My pain was from the spasms irritating my fissure. The fistula didn't seem to be the cause of the pain. I used nifidipine ointment for many months but things did not improve for me.
I had surgery a few days ago, and so far so good. The surgeon removed the fistula which was quite deep, which also required him to cut through the sphincter (resulted in a sphincterotomy). The cut-out for the fistulectomy was quite deep, the cut for just a sphincterotomy would have been significantly smaller. The surgery was done under general anaesthetic. I was knocked out and woke from what I thought was a wonderful sleep. The pain immediately after the surgery was much less than the pain before. I had a total of 2 doses of morphine pills at the hospital before being discharged the next day. I was given milder prescription pain killers which I took for another 2 days and then switched to ibuprofen as needed.
Like many, I was also afraid of the operation and avoided it until things got too severe. I wish I hadn't waited so long, and didn't suffer as I did. A lateral Internal Sphincterotomy (LIS) would have been a breeze compared to removal of the fistula.
I hope this encourages others to not deal with the pain and get a LIS if more conservative measures haven't helped. The pain after the operation is less than the pain before, and you know that the end to your pain is near.