Saturday, December 1, 2012

Anal Fissure



It is an ulcer in the longitudinal axis of the lower anal canal.

Location
  • Midline posteriorly- most common (more common in males)
  • Midline anteriorly- next most common (more common in females)

Causes
  • Due to the curvature of the sacrum and rectum, hard fecal matter while passing down causes a tear in the anal valve leading to posterior anal fissure.
  • Anterior anal fissure is common in females due to lack of support to the pelvic floor.
  • Haemorrhoidectomy
  • IBD- esp. chron’s disease
  • STD

Pathology
  • It can be acute and chronic. Fissure ends above at the dentate line.
  • Acute anal fissure
  • It is a deep tear in the lower anal skin with  spasm of anal sphincter with little inflammatory induration or edemaof its edges.
  • Chronic anal fissure
  • It has got inflamed, indurated margin with scar tissue.
  • Ulcer at its inferior margin is having a skin tag, which is edematous, acts like a guard-’ Sentinel Pile’
  • It can cause repeated infection-fibrosis-abscess foramtion-fistula formation.

Clinical features
  • Common in middle aged women, not in elderly.
  • Pain is severe in nature in acute type, whereas less severe in chronic.
  • Constipation, bleeding and discharge.
  • O/E
  • In standing cases there may be sentinel skin tag. Sentinel skin tag + typical Hx + tightly closed, puckered anus= pathognomonic. 
  • In chronic fissure, ulcer is felt with button like depression, induration and often sentinel pile.
  • The lower end of the fissure can be seen by gently parting the margins of anus.
  • Digital examination and proctoscopy is not possible in acute fissure in ano. 



Anal fissure



Sentinel pile

Differential Dx

  • Carcinoma of anus
  • Inflammatory bowel disease
  • Venereal diseases
  • Anal chancre
  • Tuberculous ulcer
  • Proctalgia fugax



Treatment

Conservative t/t
  • NO- neurotransmitter that induces relaxation of the internal spchicter.
  • Glyceryl trinitrate- being nitric acid donor, when applied as an ointment causes relaxation of the sphincter and also improves blood flow- both aids healing. 
  • Use of laxatives and xylocaine surface anaesthetic.



Surgical

Gentle dilatation of the sphincter under GA:
  • Can be used in young men with high pressure sphincter.
  • CI in pts. with weak sphincter.
  • If this method is ineffective or if the fissure is chronic with fibrosis, a skin tag or a mucus polyp, then surgery is done under GA(best) or LA.



Lateral anal sphincterotomy:
  • Here internal sphincter is divided away from the fissure either in right or left lateral positions.
  • Can be done in OPD basis under L/A.
  • Healing completes in 3 wks.
  • Good result for acute than chronic cases.
  • Small risk of incontinence.



Closed and open

Anal advancement flap:


  • Here excision of the edges of the fissure and mobilization of a square, full-thickness anal skin flap which is slided forward over the fissure and sutured in place.
  • Only little risk of damage to the underlying internal sphincter and incontinence is unlikely.

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