What are the causes and treatments of anal fissures?

From the Guidelines

Anal fissures should be initially managed with conservative treatment, including dietary and lifestyle modifications, and medical therapy, with surgical treatment considered only in the chronic phase after 8 weeks of non-operative management, using lateral internal sphincterotomy as the preferred technique. This approach is based on the most recent and highest quality evidence, which suggests that surgical treatment is not recommended for acute anal fissures, but is suggested for chronic fissures that are non-responsive to non-operative management 1. The initial management of anal fissures should focus on increasing fiber intake to 25-30 grams daily, drinking plenty of water to soften stools, and taking warm sitz baths for 10-15 minutes, 2-3 times daily to relax the anal sphincter and promote healing.

Some key points to consider in the management of anal fissures include:

• Increasing fiber intake and drinking plenty of water to soften stools and reduce the risk of further injury to the anal canal
• Using over-the-counter pain relievers like acetaminophen or ibuprofen to manage discomfort
• Applying topical treatments such as nitroglycerin ointment (0.2-0.4%) or calcium channel blockers like diltiazem (2%) to the anal area 2-3 times daily for 6-8 weeks to improve blood flow and relax the sphincter
• Considering surgical options like lateral internal sphincterotomy if conservative measures fail after 6-8 weeks, as this technique has been shown to have a high healing rate and low recurrence rate 1.

It is also important to note that anal fissures can be a symptom of an underlying condition, such as Crohn's disease, HIV/AIDS, or cancer, and that evaluation for these conditions is necessary if the fissure occurs off the midline or if there are other signs of chronicity 1. However, the primary focus of treatment should be on managing the symptoms and promoting healing of the fissure, rather than on diagnosing an underlying condition.

In terms of the timing and choice of treatment, the evidence suggests that an initial trial of conservative care alone is appropriate, particularly for acute fissures, and that surgical treatment should be considered only if the fissure is non-responsive to non-operative management after 8 weeks 1. This approach is supported by the American Gastroenterological Association, which recommends that treatment be individualized based on the chronicity of the fissure, the severity of its symptoms, and the rate and completeness of its response to conservative care 1.

From the Research

Definition and Presentation of Anal Fissures

• Anal fissure (AF) is the second most common anorectal complaint in healthcare settings 2
• The presentation might be acute or chronic, characterised by severe pain with defaecation that persists for one to two hours 2
• The aetiology of AF is unclear, although it is commonly associated with local trauma or associated chronic conditions 2

Treatment Options for Anal Fissures

• Non-surgical and surgical interventions are available based on the severity and persistence of the fissure 2
• Acute AF is first treated with conservative therapy, including dietary fibre and sitz baths 2
• Addition of topical nitrates, topical calcium channel blockers or botulinum toxin injection is indicated with failure of conservative treatment or at medical discretion 2
• Surgical options are considered if AF persists despite treatment 2
• Botulinum toxin is a more effective nonsurgical treatment compared to topical nitroglycerin ointment 3
• Glyceryl trinitrate (GTN) ointment has an efficacy of up to 68% in healing chronic anal fissure, but it is associated with headache as the major and most common side effect 4
• Diltiazem ointment achieved healing of chronic anal fissure comparable to 0.2% GTN ointment but was associated with fewer side effects 4
• The combination of nifedipine and botulinum toxin was superior to nitroglycerin and pneumatic dilatation with respect to both healing and recurrence rate 5

Efficacy of Medical Therapies for Anal Fissures

• Medical therapy for chronic anal fissure, currently consisting of topical glyceryl trinitrate, botulinum toxin injection or the topical calcium channel blockers nifedipine or diltiazem, may be applied with a chance of cure that is marginally better than placebo 6
• GTN was found to be marginally but significantly better than placebo in healing anal fissure, but late recurrence of fissure was common 6
• Botox and CCBs were equivalent to GTN in efficacy with fewer adverse events 6
• No medical therapy came close to the efficacy of surgical sphincterotomy, though none of the medical therapies in these RCTs were associated with the risk of incontinence 6