Chronic anal fissure is a linear tear in the distal anal canal. Most chronic fissures require intervention to heal. Surgical sphincterotomy is currently performed. However, the procedure permanently weakens the internal sphincter and may be associated with permanent complications such as incontinence. Current topical treatment or " chemical sphincterotomy" is effective in the short term for about 70% of the patient more than 50% of them will suffer from recurrence. Number of studies support the hypothesis that local ischemia is the reason for failure to heal in anal fissure. Treatment of refractory wounds by macrophage suspension is an innovative method since 1995, macrophage suspensions have been used successfully in more than 1400 patients in several hospitals in Israel without any side effect.Macrophages have key function in almost every stage of wound healing. They help in the digestion of bacteria, in a later stage, they secret IL-6, which influences endothelial cell proliferation and the initiation of angiogenesis.

The study hypothesis is that local injection of activated human macrophages into chronic anal fissure may induce fissure healing.