Anal Fissure Management

Diagnostic Exams

If the diagnosis remains uncertain or if a concomitant fistula is present, an examination under anesthesia with anoscopy, endoscopy or biopsy may be performed. In cases when the fissure is not readily visualized, anoscopy may often be deferred and treatment initiated based on symptoms alone. Off-the-midline, multiple, or non-healing fissures usually require further evaluation, usually with examination under anesthesia and other studies (eg biopsy, cultures, sigmoidoscopy or colonoscopy). After the diagnosis and initial treatment of an anal fissure, further evaluation is required to rule out possible secondary causes if with persistent symptoms. A digital rectal examination and anoscopy should be performed to exclude secondary causes of anal fissure, such as an anorectal malignancy. Patients with rectal bleeding should undergo endoscopy. Those with fissures or other clinical features that suggest underlying Crohn’s disease should undergo colonoscopy and imaging of the small bowel or be referred to a gastroenterologist.

Agents to Relieve Constipation¹

Fiber supplementation is given with a high-fiber diet in order to increase stool bulk. Maintenance therapy with fiber supplementation is associated with reduced rates of anal fissure recurrence compared to placebo. Stool softeners, such as Docusate sodium and Docusate calcium, diminish bleeding and pain. Lastly, laxatives help maintain regular bowel movement.

¹Please see comprehensive list of available agents for constipation in the latest MIMS.

Other Initial Measures

Topical anesthetics (eg Lidocaine) may be used to improve patient comfort and are considered safe when used as directed. Non-opioid analgesics (eg Ibuprofen, Paracetamol), either oral or parenteral, may be used for pain relief. 

Sphincter Relaxants

Calcium Antagonists

Example drugs: Diltiazem, Nifedipine

Calcium antagonists decrease resting anal pressure and anal slow and ultra-slow wave activity, and increase local blood flow. They may be considered for the first-line treatment of chronic anal fissure for 2 months. Several studies show that topical calcium antagonists appear to be as effective as treatment with topical Glyceryl trinitrate (GTN) for chronic anal fissures with fewer side effects (eg headache) and can be utilized as first-line therapy. Topical calcium antagonists have similar rates of pain relief and healing compared with the oral forms but with lower incidence of side effects. Oral calcium antagonists may be used as second-line therapy in patients with chronic anal fissures.

Nitrates

Example drug: Glyceryl trinitrate (GTN, Nitroglycerin)

 Nitrates reduce resting anal fissure and improve blood flow to the anoderm. They are often used for treatment of acute anal fissure. They may also be considered for the first-line treatment of chronic anal fissures for 2 months. Nitrates are associated with healing in approximately 50% of patients with chronic anal fissures compared to placebo. Topical GTN has been shown to significantly decrease pain during treatment. GTN may potentiate the effect of Botulinum toxin in patients being treated for refractory fissures. Patients unresponsive to topical nitrates should be referred for Botulinum toxin injection or surgery. Headache is the most common side effect and is dose related. As GTN may induce hypotension, it should be applied while seated and rapid standing should be avoided. The need for repeated applications may result in poor compliance and subsequent therapy failure for many patients. Other agents that have been studied are topical Isosorbide dinitrate ointment and spray.

Botulinum Toxin Injections  

Botulinum toxin injections inhibit acetylcholine release from presynaptic nerve terminals which achieves a chemical sphincterotomy. They help relax the hypertonic anal sphincter muscle leading to improved healing of chronic anal fissures. At higher doses, Botulinum toxin injections may also transiently decrease mean squeeze pressure. Its effect lasts about 2-3 months until nerve endings regenerate, during which time the fissure may heal. Healing in this case takes longer than after surgical sphincterotomy but return to full activity occurs sooner. As second-line therapy for chronic anal fissures after failure of conservative measures and topical therapies, Botulinum toxin shows modest improvement in rates of healing, while similar results are observed when it is compared with topical treatment as first-line therapy. Botulinum toxin injections may also be used for patients who wish to avoid surgery or are poor surgical candidates. It is preferred over lateral internal sphincterotomy (LIS) in patients at high risk of fecal incontinence (eg multiparous women, older patients). It may be considered especially in women with chronic anal fissures persisting after laxative and topical therapy or in men with fecal incontinence or who do not want to undergo surgery. Lower doses of Botulinum toxin have similar effectiveness as higher doses with lower risk of fecal incontinence. Using topical nitrates together with Botulinum toxin appears to enhance healing, and administering Botulinum toxin injections after failed topical GTN therapy may relieve symptoms and reduce the need for surgery. Subsequent injections with Botulinum toxin may be considered when the first dose failed to heal the fissure or when the fissure has healed but subsequently recurred. The most common side effect of Botulinum toxin injection is transient incontinence to flatus, and stool incontinence and transient sphincter weakness occur less commonly. The high cost of treatment is a disadvantage. Fissure recurrence after 3 months suggests that patient may benefit from surgical sphincterotomy. There is inadequate consensus on dosage, precise site of administration, number of injections needed or efficacy.  

Other Pharmacological Agents  

Other agents being used or studied for anal fissure include muscarinic agonists (eg topical Bethanechol), adrenergic antagonists (eg Indoramin), and beta₂-agonists (eg Salbutamol). Topical Bethanechol is effective in healing anal fissure without significant side effects.

Dietary Modification

Patients should be placed on a high-fiber diet. Bran has been shown to help prevent acute anal fissure recurrence. Fluid intake should also be increased to minimize risk of recurrent fissures.

Other Initial Measures

Sitz baths relax painful internal sphincter muscle spasms. Mineral oil may be used for short term to minimize stretching of the anal mucosa by easing stool passage. Furthermore, avoidance of straining protects the anoderm.

Surgery remains the gold standard of therapy for chronic anal fissure. The goal is to relax the internal anal sphincter. Several studies have shown that surgery achieves better rates of fissure healing compared with topical nitrates, calcium antagonists or Botulinum toxin injections. It is not recommended for acute anal fissures and only performed during the chronic phase after failure of at least 6-8 weeks of non-surgical therapy. It may also be considered after failure of first-line therapy even without a trial of second-line medical therapy. Topical treatments often present problems with compliance and lower rates of healing, thus making surgery a valid option after failure of first-line or conservative medical therapy. Despite its high success rate, recurrence still occurs in about 4-6% of patients, even after surgery.

Advancement Flap

Advancement flap (eg anocutaneous [dermal V-Y or house] advancement flap, anocutaneous island flap, or mucosal advancement flap) could be considered as an alternative procedure to conventional surgical treatment of chronic anal fissures. Advancement anoplasty aims to cover the open wound with a skin or rectal mucosa membrane flap. Advancement flap has been shown to achieve similar effectiveness as LIS. When used with Botulinum toxin or LIS, flaps may lessen postoperative pain, speed healing and further reduce the risk of fecal incontinence. Advancement flap may be considered in the following: Patients with baseline preoperative fecal incontinence and with inadequate response to previous treatment, and patients with low sphincter pressure fissures when conservative management fails. Anocutaneous flap is a safe alternative procedure for patients with chronic anal fissure with higher risk for fecal incontinence after LIS. It may be considered in patients with high risk of developing fecal incontinence (eg multiparous women, older patients). It is associated with decreased rates of fecal incontinence compared to LIS but with comparable healing rates. Lastly, results in primary wound healing and decreased postoperative pain when performed together with Botulinum toxin injection or LIS.

Fissurectomy

Fissurectomy involves the curettage of the base of the fissure combined with the excision of the fibrotic edges, the sentinel pile if present and any associated hypertrophied anal papilla. It may be considered in patients with high risk of developing fecal incontinence (eg multiparous women, older patients). It may also be considered in combination with Botulinum toxin injection when conservative management fails and patient has injection with Botulinum toxin. Fissurectomy has been shown to result in healing in a high percentage of patients. It may be performed in the following: Patients with minimal pain whose anal fissure failed to heal after LIS and with chronic morphologic changes (eg fibrosis, sentinel pile, rolled edges), and patients with severe pain due to a persistent or recurrent fissure after complete sphincterotomy. It has a low recurrence rate and low risk of fecal incontinence.

Lateral Internal Sphincterotomy (LIS)

LIS involves cutting fibers of the internal anal sphincter muscle up to the apex of the fissure or dentate line to relieve hypertonia. It is performed under general, spinal or local anesthesia, and is considered the procedure of choice for refractory or chronic anal fissures without baseline fecal incontinence. When done correctly, LIS appears to still be superior to medical therapy. Notably, open and closed techniques in LIS have similar results. LIS should be considered in men with chronic anal fissures persisting after laxative and topical therapy. Sphincterotomy to the dentate line may be considered. It may also be considered in women with chronic anal fissures persisting after laxative and topical therapy, although the risk of incontinence is greater in women compared with men because women have shorter internal sphincter and the female sphincter function is at risk of compromise by childbirth. Minimal incision of the muscle may be considered. It is avoided in patients at high risk for incontinence (eg multiparous women and older individuals), patients with IBD, previous history of anorectal operations or documented anal sphincter injury (eg from obstetric delivery). LIS that is tailored to the length of the fissures (also known as tailored sphincterotomy) results in similar healing rates with decreased fecal incontinence rates compared with traditional LIS extending to the dentate line. Complications of surgery include flatus or fecal incontinence, infection, bleeding and development of fistula. Persistent or recurrent pain after LIS may be attributed to insufficient sphincterotomy, sphincter hypertonia, or chronic morphologic changes within the fissure, including fibrosis, a sentinel pile, or rolled edges. If LIS is unsuccessful, a repeat sphincterotomy is recommended.