Anal fissure

Last Updated: 2020-06-25

Author(s): Anzengruber, Navarini

Intestinal rupture, anal rupture.

Anal tear of the mucosa with consequent painful defecation.

Peak age: middle adulthood.

  • Surgical interventions
  • Sexual practices
  • Crohn's disease
  • Stenoses
  • Chronic constipation with consequent hard bowel movements
  • Hemorrhoids
  • Chronic viral infections
  • Chronic bacterial infections

Poorly healing cleft fissure/rhagade usually occurring at 6 o'clock in lithotomy position, which extends from the linea dentata to the outer skin. The inner sphincter muscle may also be affected. The anal fissure is often associated with "sentinel fold" skin tags. During bowel movement, strong, cramp-like pain may occur. It is not uncommon for patients to have a pronounced fear of defecation due to pain. Consequently, spasms of the sphincter muscle may occur.

  • Medical history
    • Occurrence after sexual practices, surgery, etc?
  • Clinical features
    • Due to spasms, a clinical examination is only useful after a local anaesthetic has been administered. Inject local anaesthetics into the sphincter, then it works. 
  • Digital rectal examination
  • Proctoscopy

Anal, posterior commissure is typical (lithotomy position 6 o'clock).

  • Fistula formation
  • Periproctic abscess

The goal is to remove the excessive sphincter tonus.

General measures:

  • Stool regulation with wheat bran
  • Anal dilator (insertion with lubricant)

Surgical measures:

  • Sphincterotomy
  • Fissurectomy


  • Glyceryl trinitrate
  • Rectal ointment 3x daily for 4-6 weeks
  • Side effect: temporary headache

Botulinus toxin:

  • Intrasphinic injection. Dose 20 U in 1 mL, repeat after one week.

For persistent pain:

  • Topical anaesthetics in the form of ointments / suppositories / other
  1. Lund JN, Scholefield JH. A randomised, prospective, double-blind, placebo-controlled trial of glyceryl trinitrate ointment in treatment of anal fissure. The Lancet 1997;349:11-4.
  2. Maria G, Brisinda G, Bentivoglio AR, Cassetta E, Gui D, Albanese A. Botulinum Toxin Injections in the Internal Anal Sphincter for the Treatment of Chronic Anal Fissure. Annals of Surgery 1998;228:664-9.
  3. Fruehauf H, Wegmueller B, Bauerfeind P, Fried M, Thumshirn M. Therapy of Chronic Anal Fissure: Efficacy and Safety of Botulinum Toxin A Injection Compared to Topical Nitroglycerin Ointment. Z Gastroenterol 2005;43.