Chronic Anal Fissure

Abstract

A chronic anal fissure is a non-healing ischaemic ulcer of the anal canal. Internal sphincter hypertonia is the usual underlying pathophysiology, but a significant number of patients may have normal or low resting anal pressures. Traditional surgical management for chronic anal fissure is aimed at treating sphincter spasm. Manual anal dilatation risks unacceptable rates of permanent faecal incontinence. Lateral internal sphincterotomy is very effective in terms of fissure healing, but similar concerns exist regarding continence disturbance. Various technical modifications to tailor sphincterotomy and careful patient selection can make sphincterotomy safer. Medical treatment of chronic anal fissure has developed more recently. Topical glyceryl trinitrate (GTN), topical diltiazem and botulinum toxin injection (BTX) are not as effective as sphincterotomy but do not risk long-term faecal incontinence. Therefore, topical treatments are recommended first-line, with BTX as second-line for those who only partially respond or relapse. Fissurectomy can be performed concurrently with BTX to treat the chronic fibrosis that may otherwise contribute to poor healing rates. Advancement flap is an effective surgical treatment and should be used in preference to lateral sphincterotomy if there are any risk factors for incontinence. Patients who do not respond at all to topical creams should undergo anorectal physiology studies. Patients with low or normal pressure fissures may have symptoms of obstructed defaecation syndrome and should be investigated for anorectal dysfunction. Lateral sphincterotomy should be reserved for a select group of patients who have failed other therapies and with appropriate informed consent regarding long-term risks.