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Anal fissure

What's new

Updated 2023 SIUCP guidelines for the diagnosis and management of anal fissures.



AFs refer to an anorectal disorder characterized by a tear in the squamous epithelium of the anus, distal to the dentate line. Fissures are defined as acute if present for < 6 weeks, and they are defined as chronic if present for > 6 weeks.
Various risk factors increase the risk of AFs, mediating their effects via mechanical tissue trauma, ischemia of the anal canal, impaired sphincter structure or function, or anal hypertonicity.
The annual incidence of AFs in the US is estimated at 110 cases per 100,000 person-years.
Disease course
AFs may cause clinical manifestations of anal pain, spasm, and/or bleeding with defecation.
Prognosis and risk of recurrence
Medical treatment is associated with over 70% success rates. Surgical treatment, which is typically reserved for patients in whom medical therapy fails, yields excellent outcomes.


Key sources

The following summarized guidelines for the evaluation and management of anal fissure are prepared by our editorial team based on guidelines from the American Society of Colon and Rectal Surgeons (ASCRS 2023,2017), the Italian Unitary Society of Colon-Proctology (SIUCP 2023), the American College of Gastroenterology (ACG 2021), the World Society of Emergency Surgery (WSES/AAST 2021), and the Association of Coloproctology ...
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Screening and diagnosis

Etiology: as per ACPGBI 2008 guidelines, recognize that AFs associated with internal anal sphincter hypertonia are probably ischemic in nature.
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  • Diagnosis

  • Differential diagnosis

Diagnostic investigations

Physical examination: as per SIUCP 2023 guidelines, consider performing clinical examination as the initial evaluation of sphincter hypertonia in patients with AF.

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  • Diagnostic imaging

  • Functional evaluation

  • Laboratory tests

Medical management

Indications for nonoperative management: as per ASCRS 2023 guidelines, offer nonoperative management as first-line therapy in patients with acute AF.

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  • Topical nitrates

  • Topical CCBs

  • Topical antibiotics and anti-inflammatory agents

  • Pain management

Nonpharmacologic interventions

Dietary modifications: as per SIUCP 2023 guidelines, consider offering fiber supplements and bulk-forming laxatives in patients with persisting hard stools.

Therapeutic procedures

Botulinum toxin injections
As per ASCRS 2023 guidelines:
Administer botulinum toxin injection as first-line therapy in patients with chronic AF and as second-line therapy following failed treatment with topical therapies.
Insufficient evidence to recommend repeat botulinum toxin injection in patients with recurrent AF, although short-term outcomes have shown good healing rates with a low risk of fecal incontinence.

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  • Anal dilatation

  • Tibial nerve stimulation

Surgical interventions

Indications for surgery
As per AAST/WSES 2021 guidelines:
Avoid performing surgery in patients with acute AF.
Consider performing surgery in patients with AF in the chronic phase not responding after 8 weeks of nonoperative management.

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  • Lateral internal sphincterotomy

  • Anocutaneous flap

  • Fissurotomy and fissurectomy

Specific circumstances

Pediatric patients: as per ACPGBI 2008 guidelines, offer conservative management initially in pediatric patients with AF. Offer topical nitroglycerin or CCBs if conservative management fails. Reserve lateral sphincterotomy or fissurectomy for cases failing to heal with medical treatment.