Dr.Nikita Patil

Medical Science

      (FISSURE – IN – ANO)

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  EAS – External anal sphincter IAS – Internal anal sphincter

1) DEFINITION OF Anal fissure :- 

    Anal fissure is a small, superficial ulcer present along the longitudinal axis of lower part of anal canal. It can be present in the midline, posteriorly, or anteriorly. Anterior ulcers are more common in females.

2) EXTERNAL ANAL SPHINCTER ANATOMY:-

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  Three parts:-

  (a) Deep part – It encircles the upper end of anal canal. There is no bony attachment.

  (b) Superficial part – It is attached posteriorly to coccyx & anteriorly to mid perineal

point in males & to vaginal sphincter in females.

  (c) Subcutaneous part – It encircles the lower part of anal canal. There is no bony

attachment.

3) INTERNAL ANAL SPHINCTER ANATOMY:-

It covers upper two third of anal canal. It is formed by thickening of circular muscles which are continued from the bowel above. Spasm & contraction of sphincter causes fissure & other anal infections.

4) CAUSES OF ANAL FISSURE:-

Anal fissure is caused due to tearing of anal canal due to trauma & ulcer formation at that place. 

Following are the causes for trauma:-

   (a) Hard stools – Can cause sphincter to contract more forcefully leading to tear.

   (b) Trauma 

   (c) Diarrhoea – Repeated diarrhoea causes damage to anal mucosa.

   (d) Sexually transmitted disease (STD)-

  eg. syphilis , gonorrhoea (inflammation & damage)

   (e) Ischemia – Decrease in blood flow delays healing & hastens tissue damage.

   (f) Increased sphincter tone – It decreases the blood supply to the anus & thus slows down the healing process. This can cause anal tear to develop.

   (g) TB – inflammation & ulcer formation.

   (h) Crohn’s disease – inflammation & ulcer formation.

   (i) Ulcerative Colitis – inflammation & ulcer formation.

   (j) Anterior fissure is more common in females than males because there is weak support for the anterior anal canal due to the presence of vagina anterior to anus.

   (k) haemorrhoidectomy – trauma during surgical procedure.

5) PATHOPHYSIOLOGY OF ANAL FISSURE:-

   (a) The above causes may cause tear to the anal mucosa leading to fissure.

   (b) Due to fissure, the internal sphincter remains contracted & doesn’t relax  because damage to anal mucosa leads to hypersensitivity of receptors in the  sphincter resulting in overreaction of the continence reflex & hence the spasm of  sphincter occurs.

   (c) Spasm of sphincter leads to decreased blood flow which further delays healing of the fissure which can transform the acute fissure into chronic fissure. 

   (d) Pain occurs in fissure due to skin damage, nerve damage & stimulation of  nociceptors present in damaged tissues. This pain can be aggravated by ischemia  & infection. The pain can also occur due to sphincter spasm because spasm leads to ischemia (leading to drop in pH & release of pain producing substances like

bradykinin, ATP, H+)

6) TYPES OF FISSURES:-

  (a) Acute anal fissure – tear with clean & sharp margins, no inflammation & edema,

severe pain, constipation & spasm of sphincter.

  (b) Chronic anal fissure –

    # The margins are rolled out & fibrosed.

   # Inferior part of fissure has skin tag which is edematous & guards the fissure -sentinel pile. The upper part shows hypertrophic papilla.

    # Chronic fissure is inflammed & edematous.

    # There is less pain.

    # It may undergo infection, abscess formation, fibrosis or fistula formation.

    # Multiple fissures – present in homosexuals, Inflammatory Bowel disease.

7) CLINICAL FEATURES OF ANAL FISSURE:-

  (a) Pain (explained in pathophysiology)

    # Severe in acute cases.

    # Less severe in chronic cases – nerve endings are in the process of healing.

  (b) Bleeding, discharge – due to ruptured blood vessels or due to abscess

   formation.

  (c) Constipation – due to pain & spasm.

  (d) In case of acute fissure, Per rectal examination or proctoscopy cannot be done.(General anaesthesia is required).

  (e) In case of chronic fissure, Per rectal examination can be done & it can be felt  as BUTTON LIKE DEPRESSION with enduration & sentinel pile.

8) DIFFERENTIAL DIAGNOSIS:-

  (a) Anal carcinoma.

  (b) Anal chancre.

  (c) TB of anus.

  (d) Veneral diseases.

9) TREATMENT OF ANAL FISSURE :-

  (a) General measures :

    # Drink plenty of water – so that stool doesn’t become hard.

    # Fibre rich diet – soft stools.

    # Stool softener – Lactulose. Bulk forming agent – Psyllium.

    # Application of local anaesthetic – lignocaine, xylocaine.

    # Sitz bath – increases blood flow & relaxes muscles.

    # Regular anal dilatation.

  (b) Acute fissures:-

    # Under general anaesthesia, dilatation of anal sphincter is done by manual stretching using two fingers of each hand to relieve the spasm of sphincter.

    # Bed rest

    # Application of local anaesthetic (Xylocaine) or Nifedipine ointment (causes relaxation of muscles – Calcium Channel Blocker),Laxatives.

  (c) Chronic fissure:-

    # Fissurectomy(excision of fissure) with Sphincterotomy (cutting open of the sphincter & not complete excision) – Sample is sent for ruling out Carcinoma, TB.

    # Botulinum toxin – It prevents the release of Acetylcholine at neuromuscular junction which causes relaxation of sphincter.

    # Nitroglycerin- GTN – It decreases the tone of sphincter muscle by release of nitrate which is converted into nitric oxide which is a smooth muscle relaxant.

    # Diltiazem – Calcium Channel Blocker- Smooth muscle relaxation.

    # Regular anal dilatation.

    # Lateral anal sphincterotomy – Internal sphincter is divided away from the site of fissure by open or close method.

      CLOSE METHOD – Blade is inserted & moved upwards in the intersphincteric    groove. (between external & internal anal sphincter) Then, blade is moved medially to cut the internal sphincter.

      OPEN METHOD – Incision outside the anal verge.(junction of perianal skin & anal epithelium) – dissection of hypertrophied internal sphincter & it’s division. Wound is left open.

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