I've had problems with fissures for around ten years. I didn't see a GP until fall 2010 after daily spasms and bleeding for weeks. He prescribed Movicol and Ultraproct cream and I noticed improvement within two weeks. I continued to buy Movicol over the counter and I only had a few minor episodes between fall 2010 and two weeks ago. It is worth mentioning that I started getting diarrhea after taking Movicol early this year. I stopped taking Movicol and the fissure was back within a couple of weeks with painful BMs and bleeding.
My new GP prescribed Laxido (generic version of Movicol) two weeks ago and I was pain free within four days. I saw my GP today and he gave me a repeat prescription for Laxido and I'm hopeful I'll be able to manage my fissure again with the Laxido.

The bottom line is: keep the stool soft to very soft without it being diarrhea and it's possible to keep fissures under control without surgery. I do eat a healthy low fat diet with lots of veggies and I try to go for a 30 minute walk every day at lunch. I also avoid things that make me 'sluggish'. What makes you sluggish appears individual but I need to avoid too much bread, wheat based products and too much fiber.