To evaluate whether effectively treating anal fissure-associated constipation using oral PEG alone can eliminate the inconvenience of add topical agent such as DTZ. As previous studies have shown the topical agent are more effective in treating anal fissure when combined with less effective laxatives

Anal fissure (AF) is common among children attending pediatric and surgery clinics and is frequently associated with painful defecation, stool withholding and constipation which affect 1%-30% of the pediatric population. Constipated children consume low fiber diets, come from lower socioeconomic families and tend to be obese. The reason why anal fissure develops is still largely unclear, however the pathogenesis points to an initial anal trauma cause by the hard stool leading to anal sphincter hypertonia or spasm which cause local ischemia and non-healing ulcer. It is not clear why the posterior anal canal is the most affected part by the local anal ischemia.

Current medical therapy for chronic anal fissure focuses on alleviating the two main pathologies by using anal sphincter relaxing topical ointments and laxative to treat associated constipation. The classical text book described treatment of AF focus on increasing fiber intake to treat the underlying constipation. Jensen et al, has found that treating the first episode of anal fissure with bran is more effective than local anesthetic or steroids. The American Society of Colon and Rectal Surgeons practice parameters suggest that increase in fluid and fiber ingestion, use of sitz baths, and if necessary use of stool softeners are safe have few side effects and should be the initial therapy for all patients with anal fissure.

There have been many recent randomized trials describing the effectiveness of Nitroglycerin (NTG), Botulinum toxin injection or the topical calcium channel blockers such as Diltiazem (DTZ) in adult and pediatric. A systematic review of the available randomized trials of these agents has shown that topical agents are marginally better than placebo [15]. Furthermore, in most trials that have demonstrated the effectiveness of topical agents laxatives usage was either not well controlled or lactulose was the main agent used. In children, many recent randomized trials have demonstrated the superior effectiveness of PEG over lactulose consequently; we think that treating AF with PEG is likely to improve the success rate and lead to persistent log-term fissure healing. Most adults and pediatric RCTs that have demonstrated the effectiveness of topical agents in healing AF, have focused on comparing various topical agents to placebo in treating AF, however the effectiveness in comparison to placebo has never been demonstrated in patients how are placed on more effective laxative such as PEG. We hypothesize that replacing lactulose with a more effective laxative such PEG as a sole agent to treat AF can eliminate the effectiveness and therefore the need to add topical sphincter relaxing agent such DTZ or NTG. Laxative-only treatment is likely to be more convenient and more cost-effective.

Inclusion Criteria:

1. Painful defecation with visible anal fissure
2. Symptoms for 2 weeks
3. Children less than 14 years of age

Exclusion Criteria:

1. Previous surgeries
2. Chronic illness affecting the rectum or perianal area
3. Refuse to participate