Fissure

• An anal fissure (fissure in ano) is a longitudinal and superficial tear of the epithelium and dermis at the anal margin extending up into the anal canal but below the dentate line.
• Anal fissures are a multifactorial condition with many risk factors (with constipation being the most common).

  Pathophysiology that increases the risk of development of fissures include:

  • Mechanical/traumatic: due to the passage of a hard and bulky stool at the origin of an anodermal tear
  • Hypertonia of the internal anal sphincter: this is thought to reduce the blood supply to the anus and thus slows down the healing process
  • Ischaemia: hinders the healing of the fissure
• Risk factors for the development of an anal fissure include:

  • Constipation
  • Low fibre diet
  • Conditions that damage anal mucosa -IBD, anal cancer, dermatological conditions
  • Chronic diarrhoea
  • Pregnancy and childbirth
  • Opioid analgesia: due to constipation
  • Trauma e.g. surgery and anal sex
• Typical symptoms of anal fissures include:2-5

  • Pain around the anus
  • Painful defecation (described as ‘feeling like passing broken glass’)
  • Rectal bleeding
  • Abdominal pain (rare)
• Consider ruling out associated systemic causes such as malignancy and inflammatory pathology by asking about:

  • Vomiting
  • Loss of appetite
  • Weight loss
• In the context of a suspected anal fissure, examination of the perianal area may reveal a sentinel pile. The anal fissure itself is typically located in the posterior aspect, and can be observed by gently parting the perianal skin.
• A digital rectal examination is necessary but might not be possible due to the intense pain, and patients may require examination under anaesthesia (EUA)
• If tolerated, visual examination of the anal canal can be carried out using a proctoscope.

  Clinical findings include:

  • Fissures can be palpable or visible around the anus
  • A tear can be seen on the posterior aspect
• Conservative management:

  • Treat underlying cause/reduce risk factors
  • Analgesia - sit in shallow warm bath, paracetamol or ibuprofen (avoid opiates), topical lidocaine 5% ointment (to use before passing stool)
  • Dietary modification - high fibre and fluid intake, laxatives if required
  • Rectal GTN 0.4% ointment - BD for 6-8 weeks - common side effect of headaches
  • GTN increases blood supply to region and relaxes internal anal sphincter
  • Topical calcium channel blocker
• Surgical management:

  • Examination under anaesthetic and botox injections to the internal anal sphincter
  • Lateral sphincterotomy - division of the internal anal sphincter (risk of incontinence)
  • Fissurectomy - cut out scarred superficial skin around fissure and either close wound or leave to heal by secondary intention - turns chronic fissure into an acute one but hope it will heal after
  • Anal advancement flap - do a fissurectomy and then put a flap of healthy anal tissue on top
• Classification:

  • Acute = present for <6 weeks
  • Chronic = present for >6 weeks
  • Primary = no clear underlying cause
  • Secondary = clear underlying cause
• Peak incidence in 15-40 year olds but can occur at any age

  • Uncommon in the elderly, be suspicious of pain and bleeding in this age group
• Location:

  • Majority occur on the posterior midline of the anal canal (less blood flow compared to other areas)
  • Fissures from childbirth tend to be anterior