Anal Fissure Xử trí

Other Diagnostic Exams

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. 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.

First-line Therapy

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 Measures

Topical anesthetics (eg Lidocaine) may be used to increase patient comfort and they cause no harm. Non-opioid analgesics (eg Ibuprofen, Paracetamol) 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. 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 and can be utilized as first-line therapy.

Nitrates

Topical GTN has been shown to significantly decrease pain during treatment. It reduces resting anal fissure and improves blood flow to the anoderm. Nitrates may be considered for the first-line treatment of chronic anal fissures for 2 months.

Second-line Therapy

Second-line therapy is aimed at reversibly decreasing resting anal pressure with the goal of allowing the fissure to heal without permanent sphincter damage. It may be used for patients wanting to avoid or who are not candidates for surgical therapy.

Sphincter Relaxants

Calcium Antagonists

Oral calcium antagonists may be used as second-line therapy in patients with chronic anal fissures. Topical calcium antagonists have similar rates of pain relief and healing compared with the oral forms but with lower incidence of side effects. Lastly, topical Diltiazem should be applied three times a day for 8 weeks.

Nitrates

Nitrates are associated with healing in approximately 50% of patients with chronic anal fissures compared to placebo. GTN may potentiate the effect of Botulinum toxin in patients being treated for refractory fissures. Headache is the most common side effect and is dose related. 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 & spray. Patients unresponsive to topical nitrates should be referred for Botulinum toxin injection or surgery.

Botulinum Toxin Injections

Botulinum inhibits acetylcholine release from presynaptic nerve terminals which achieves a chemical sphincterotomy. It helps relax the hypertonic anal sphincter muscle leading to improved healing of chronic anal fissures. At higher doses, Botulinum 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 after 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 for chronic anal fissures. 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. 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 injection is transient incontinence to flatus and stool incontinence occurs 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. Lidocaine and Hydrocortisone may also be considered.

First-line Therapy

Diet Modification

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

Other 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. 

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 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.

Advancement Flap

Advancement flap, 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. It has been shown to achieve similar effectiveness as lateral internal sphincterotomy (LIS). 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 and sentinel pile if present. 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. 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 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 inflammatory bowel disease (IBD), previous history of anorectal operations or documented anal sphincter injury. 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 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.