Clinical Evidence Handbook A Publication of BMJ Publishing Group

Chronic Anal Fissures RICHARD L. NELSON, Northern General Hospital, Sheffield, United Kingdom

This is one in a series of Chronic anal fissures typically occur in the • Open partial lateral internal anal chapters excerpted from midline, with visible sphincter fibers at the sphincterotomy may be equivalent to closed the Clinical Evidence Handbook, published by fissure base, anal papillae, sentinel piles, and partial internal anal sphincterotomy in fis- the BMJ Publishing Group, indurated margins. sure healing. London, U.K. The medical • Anal fissures are a common cause • Longer division information contained of anal pain during and for one to two (to the dentate line, as opposed to the fissure herein is the most accurate available at the date of hours after defecation. The cause is not fully apex only) may be more effective at reducing publication. More updated understood, but low intake of anal fissure. and comprehensive infor- may be a risk factor. The risk of minor flatus or fecal inconti- mation on this topic may Chronic fissures typically have a cycli- nence is greater with internal anal sphinc- be available in future print • editions of the Clinical Evi- cal history of intermittent healing and recur- terotomy than with . dence Handbook, as well rence, but about 35% will eventually heal, at Topical increases the risk as online at http://www. least temporarily, without intervention. of headache compared with internal anal clinicalevidence.bmj.com (subscription required). • Atypical features, such as multiple, sphincterotomy. large, or irregular fissures, or those not Postsurgical may be This series is coordinated in the midline, may indicate underlying confused with postsurgical leakage (a short- by Kenny Lin, MD, MPH, Associate Deputy Editor malignancy, sexually transmitted infections, term adverse effect). Confirming postsurgi- for AFP Online. inflammatory bowel disease, or trauma. cal leakage requires long-term follow-up (at

A collection of Clinical Internal anal sphincterotomy is more least 12 months). Evidence Handbook pub- effective than medical therapy for chronic lished in AFP is available anal fissure in adults. It improves fissure Definition at http://www.aafp.org/ healing compared with treatment with nitric An anal fissure is an ulcer or tear in the squa- afp/bmj. oxide donors (topical nitroglycerin, topical mous epithelium of the distal , CME This clinical content isosorbide dinitrate), botulinum A toxin– usually in the posterior midline. Persons conforms to AAFP criteria for continuing medical hemagglutinin complex, and calcium chan- with an anal fissure usually experience pain education (CME). See nel blockers (, diltiazem). during defecation and for one to two hours CME Quiz Questions on • Internal anal sphincterotomy also afterward. Multiple fissures and large, irreg- page 449. increases fissure healing compared with ular, or large and irregular fissures, or fis- Author disclosure: Richard digital anal stretch, and anal stretch is more sures off the midline are considered atypical. L. Nelson has received likely to cause flatus incontinence. One Atypical fissures may be caused by malig- fees from the American small randomized controlled trial found nancy, chemotherapy, sexually transmitted College of Physicians for web-based education limited evidence that controlled anal dila- infections, inflammatory bowel disease, or modules. He is also the tion may be equivalent to sphincterotomy in other traumas. Treatments for atypical fis- author of references cited fissure healing, with negligible incontinence sures are not included in this review. It is in this review. risk. not clear what the best treatment strategy is • We do not know whether anal dilation in persons who present with a painless anal is more effective than topical nitroglycerin fissure and in whom an atypical etiology has at reducing the proportion of persons with been ruled out. anal fissure. Acute anal fissures have sharply demar- • We do not know whether internal cated, fresh mucosal edges, often with anal sphincterotomy is better or worse than granulation tissue at the base. Acute fis- anal advancement flap in improving fissure sures are believed to often heal spontane- healing. ously. Anal fissures persisting for longer

498 American Family Physician www.aafp.org/afp Volume 93, Number 6 ◆ March 15, 2016 Clinical Questions

What are the effects of surgical treatments for chronic anal fissure? Beneficial Internal anal sphincterotomy (more effective than nitric oxide donors, botulinum A toxin–hemagglutinin complex, calcium channel blockers, or anal stretch) Unknown Anal advancement flap (limited evidence effectiveness that it is as effective as internal anal sphincterotomy based on one small randomized controlled trial) Unlikely to be Anal stretch (less effective than internal beneficial anal sphincterotomy)

than four weeks, or recurrent fissures, are generally defined as chronic. Chronic anal fissures have distinct anatomical features, such as visible sphincter fibers at the fissure base, anal papillae, sentinel piles, and indu- rated margins. Most published studies only require the presence of one of these signs or symptoms to classify a fissure as chronic. This review addresses only chronic anal fissures. Incidence and Prevalence Keep up with Anal fissures are a common cause of anal pain in all age groups, but we found no reliable evidence about precise incidence. the latest in Etiology and Risk Factors The cause of anal fissure is not fully understood. Low family medicine intake of dietary fiber may be a risk factor for the devel- opment of acute anal fissure. Persons with anal fissure often have raised resting anal canal pressures with anal research. , which may give rise to ischemia. Prognosis Order your print Chronic anal fissure typically has a cyclical pain his- tory, with intermittent healing and then recurrence. subscription today. One systematic review found healing rates of about 35% without intervention, depending on the length of study follow-up.

SEARCH DATE: January 2014 Adapted with permission from Nelson RL. Anal fissure (chronic). Clin Evid Handbook. December 2015:145-146. Visit http://www. clinicalevidence.bmj.com for full text and references. ■

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