Incontinence after sphincterotomy

Hi,
I have had an anal fissure which developed 6 weeks post partum, and has been there on and off for 18 months now. It only flares up perhaps once a month and when it does, I can get it to heal fairly fast by taking more laxatives than normal. I have to take stool softeners each day to try and prevent it from rearing it's painful head, and so have been offered a sphincterotomy which I am hesitant to have, as have heard horror stories about people leaking faeces and mucus after the surgery due to lack of muscle control! (I also already have some nerve damage down there already, so I dont think my muscle control is as good as it could be now). Has anyone who has had this surgery had problems with leakage? Or other permanent effects?