- Most acute fissure heal spontaneously
- Chronic fissures (more than 6 weeks) duration associated with increased intra-anal pressure
- Treatment aimed at reducing anal sphincter pressure
- Probably due to mucosal ischaemia secondary to muscle spasm
- Probably not a 'tear' due to the passage of a hard stool (Pecten band theory)
- 5% associated with chronic intersphinteric abscess
- Usually seen between 30 and 50 years
- 90% posterior midline
- 10% anterior midline
- Anterior fissure more common in women – specially post partum
- If multiple fissure or at unusual site consider
- Crohn's Disease
- Present with pain on defecation, bright red bleeding and pruritus ani
- Fissure often visible on parting of buttocks and or a 'sentinel pile'
- Features of chronicity:
- Symptoms for more than 6 weeks
- Undermined edges
- Visible internal sphincter
- Bulking agent and topical local anaesthesia produces symptomatic improvement
- 50% of acute fissures heal with this treatment
- Recent interest in the use of 0.2% GTN ointment for treatment of chronic fissures
- GTN is nitric oxide donor that relaxes internal anal sphincter
- Induces a 'reversible chemical sphincterotomy'
- Reduces anal resting pressure by 30 – 40 %
- Heals more than 70% fissures by 6 weeks with about a 10% risk of early recurrence
- Most common side effect is headache
- Similar results to GTN achieved with diltiazem
- Botulinum toxin also produces a chemical sphincterotomy
- 95% achieve prolonged symptomatic improvement
- 20% some degree of incontinence (faecal soiling or incontinent of flatus)
- Anal dilatation or internal sphincterotomy are the two most common procedures
- Sphincterotomy more effective and has a reduced risk of incontinence
- Lateral sphincterotomy preferred
- Posterior sphincterotomy or fissurectomy should be avoided.
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