Advice
Intervention and alternatives
Most medical treatments for chronic anal fissure aim to reduce anal sphincter tone (Cross et al. 2008). Botulinum toxin is a protein complex derived from Clostridium botulinum. In botulinum toxin type A, the protein consists of type A neurotoxin and several other proteins. The protein complex blocks the release of acetyl choline at presynaptic cholinergic nerve terminals (see Botox summaries of product characteristics).
The evidence for the effectiveness of 2 unlicensed alternatives is discussed in detail in 2 previous evidence summaries:
Condition
Adults
Anal fissure is a common and painful problem that involves a tear or ulcer in the squamous epithelium of the anus. It usually occurs between the ages of 20 and 40 with an equal distribution between men and women and a lifetime incidence of 11.1% (Cross et al. 2008). Most of the fissures are in the midline posteriorly, whereas about 8% occur both posteriorly and anteriorly (Cross et al. 2008).
Chronic fissure has both anatomical and temporal definitions that vary. A Cochrane review of non-surgical treatments for chronic anal fissure states that chronicity is defined as a history of pain lasting more than 4 weeks or with pain of less duration but similar episodes in the past. NHS Choices states that anal fissure is chronic if symptoms have lasted for more than 6 weeks. Physical characteristics of chronicity include a sentinel pile at the distal margin of the fissure, heaped up edges of the fissure, visible sphincter fibres at the base of the fissure or an inflammatory polyp at the inner margin of the fissure (Nelson et al. 2012).
The Association of Coloproctology of Great Britain and Ireland states that symptoms of anal fissure include anal pain during and after defecation that may last for several hours. Bleeding is common and the most consistent finding on physical examination is spasm of the anal canal because of hypertonia of the internal anal sphincter.
The aetiology of a typical anal fissure is not clear but trauma from passing a large or hard stool is a common cause (Cross et al. 2008). Other less common causes include inflammatory bowel disease, anal cancer, childbirth and sexually transmitted disease (Cross et al. 2008 and Orsay et al. 2004).
Children
It is not certain whether chronic fissure in children is comparable to chronic fissure in adults or has the same aetiology (Nelson et al. 2012).
According to the Association of Coloproctology of Great Britain and Ireland, most fissures occur in children aged between 6 and 24 months, usually as a result of a mechanical tear. If a chronic fissure develops, associated underlying pathologies should be ruled out, as in adults. An acute fissure usually heals in 10–14 days with conservative treatment (such as dietary changes). If the fissure persists for 6–8 weeks, medical treatments are usually considered.
Alternative treatment options
Reduction of the increased pressure on the anal sphincter is associated with relief of pain and fissure healing (Samim et al. 2012). Conservative treatments include softening stools through laxatives or a high-fibre diet, as well as using topical anaesthetics or analgesics (Cross et al. 2008). Surgical lateral sphincterotomy is regarded as the current 'gold standard' treatment and is highly effective, resulting in fissure healing in more than 90% of patients (Nelson et al. 2011 and Samim et al. 2012). However, a significant minority of people who have surgery experience incontinence, and some reports have suggested that up to 30% of patients have difficulty controlling flatus and 3–10% have episodes of leakage after surgery (Cross et al. 2008). Another high-quality review suggests that up to 5% of patients have anal incontinence after surgery (Nelson et al. 2011). Consequently, non-surgical options have been sought.
In the UK, 0.4% topical glyceryl trinitrate (GTN) is the only licensed non-surgical treatment for chronic anal fissure. A Cochrane review found that GTN was marginally, but statistically significantly, better than placebo in healing anal fissure (48.9% compared with 35.5% respectively, p<0.0009; most RCTs were in adults), but late recurrence of fissure was common, occurring in about 50% of people whose fissures were initially cured.
The summary of product characteristics for Rectogesic 4 mg/g rectal ointment states that headache is very commonly reported by people using 0.4% GTN. Although they can be treated with analgesics such as paracetamol, the headaches may be severe (frequency 1 in 5 people using 0.4% GTN) and can cause people to discontinue treatment. Dizziness is also commonly reported (frequency greater than 1 in 100, but less than 1 in 10).
Alternative non-surgical treatments for chronic anal fissure include unlicensed 0.2% topical GTN ointment, unlicensed 2% topical diltiazem cream and off-label botulinum toxin type A injection (Nelson et al. 2012).
The evidence for the effectiveness of 2 unlicensed alternatives is discussed in detail in 2 previous evidence summaries:
Children with anal fissure are treated conservatively initially. If this fails, the Association of Coloproctology of Great Britain and Ireland has suggested trying local GTN or calcium-channel blockers. Surgery is rarely indicated for children, in whom the surgical technique is the same as for adults.