Anal Fissure

An anal fissure is split in the skin of the anal canal.   They are relatively common with about one person in ten developing an anal fissure at some point in their lifetime.

Symptoms of an anal fissure

The following symptoms may occur with an anal fissure:

  • Anal pain; often patients complain of severe anal pain, particularly following defecation.  The pain is often very sharp and sometimes described like “passing glass”.  This can last for up to 2 hours after defecation.
  • Rectal bleeding; There may be some blood on the toilet paper or in the toilet pan.  See “rectal bleeding” information page for more about this symptom.
  • Skin tag; patients with an anal fissure will often grow a sentinel skin tag at the anus.  This is sometimes felt on wiping and can lead to hygiene issues and an itchy bottom (pruritis ani).
  • Anorectal abscess; more rarely some patients develop an abscess at the anus with the underlying cause being an anal fissure.  See “anal fistula and anorectal abscess” information page for more information.

How is an anal fissure diagnosed?

If an anal fissure is suspected you would often be referred to a colorectal surgeon such as Mr Denzil May.  An anal fissure is usually diagnosed on clinical grounds, by the clinical history and examination findings.  When further tests are required they are to investigate underlying symptoms such as rectal bleeding rather than to look for a fissure per se.  This would usually be a flexible sigmoidoscopy.

Treatment of an anal fissure

The underlying problem that prevents a fissure from healing, and also the cause of the severe anal pain associated with an anal fissure, is spasm of the internal anal sphincter.  The spasm means that blood supply to the anal skin is reduced, and the fissure therefore fails to heal.

Treatment is aimed at softening the stool and reducing internal sphincter spasm.

Stool Softening Medication

There are many different laxatives available.  Most of the time fybogel is adequate to aid defecation.  The aim is to keep the stool soft but formed.  Other laxative regimes may be required.  Discuss this with Mr Denzil May when you see him in the outpatient clinic at the Duchy Hospital.

Medication to reduce internal sphincter spasm

GTN ointment

0.4% GTN ointment (Rectogesic 4mg/g rectal ointment) is the only GTN ointment that is licenced in the UK to treat anal fissure for adults (over 18) only.  0.2% GTN ointment is often used, but this is done off licence.  There is some weak evidence that there is no increased efficacy with 0.4% over 0.2% GTN ointment, but an increase in side effects such as headache.

2% Diltiazem Ointment

Diltiazem is a calcium channel blocker that causes muscle relaxation and diltiazem ointment has benefit in treatment of an anal fissure.  Often diltiazem ointment is used second line by a specialist colorectal surgeon such as Mr Denzil May.  It is currently unlicensed in the UK.  Side effects such as headache are less common than with GTN ointment, but sometimes can cause anal itching.


If the topical ointments described above are not successful in achieving healing of the anal fissure there are surgical options available.

Botulinum Toxin A (botox)

An examination under anaesthetic is performed as a simple day case operation at the Duchy Hospital, Truro.  If there are associated skin tags or if there is poorly formed granulation tissue overlying the fissure this is cleaned and “botox” is injected into the intersphincteric space.  The effects of this last for approximately 3 months and usually the fissure will heal in this time.  Sometimes repeated injections are required.

Lateral sphincterotomy

A lateral or internal sphincterotomy involves dividing a small portion of the internal anal sphincter.  This tends to be reserved for male patients only who have failed other treatments already described.  There is small risk of incontinence with this treatment, and usually only to flatus.  The risk of incontinence is much higher in women due to the shorter length of the anal sphincter complex.

Advancement flaps

An anal advancement flap is very rarely used.  This risks and likely outcomes will be discussed with you if necessary.

Risks of surgery

As with any operation complications can occur.  Fissure surgery is very low risk and is usually performed as a day case procedure under a short general anaesthetic.  This is a routine operation at the Duchy Hospital, Truro, Cornwall.

The main risks are:


This is an extremely rare complication for both botox injection and lateral sphincterotomy but is possible with any type of surgical intervention.  If it occurs it sometimes requires a course of antibiotics and rarely further surgery to drain an abscess.

Faecal incontinence

Incontinence ranges from being unable to control flatus (wind) through to complete incontinence of flatus and stool.  Incontinence is very rare.  This specific risk will be discussed with you in the outpatient clinic prior to surgery. 

Fissure Recurrence or failure of treatment

There is possibility that the fissure fails to heal or recurs despite surgery.  If this occurs further treatment and further surgical intervention may be necessary.

General risks of surgery and anaesthesia

Modern anaesthetics are very safe.  Most people are not affected.   Rarely some patients develop a reaction to the anaesthetic, or develop a blood clot in the leg (deep vein thrombosis) that can go to the lung (pulmonary embolism).  Patients at risk of this are given compression stockings (TEDS) to wear.  Very rarely patients may suffer a heart attack or a stroke as result of anaesthesia and surgery.

After your operation

Following discharge from hospital you will be given painkiller medication, and sometimes antibiotics and laxatives.  Take these as prescribed.  You can shower and bath immediately.  Spare dressings and instructions will be provided on discharge.

There are no restrictions on diet following surgery.  However it’s advised, for the first 3-5 days to eat relatively light and bland food, and avoid fizzy drinks.

After surgery it is best to walk and mobilise gently, and gradually build up to normal activity as you feel able.  You should avoid heavy lifting for the first 2 weeks following surgery.

You should be able to drive after about 3 days.  However if you are taking strong painkillers sometimes these affect your ability to drive.  If in doubt seek medical advice prior to driving.

Going back to work depends on your job.  Most patients are able to return to work by about 1-2 weeks.  Specific advice to you will be made on discharge following your operation.

Complications after discharge are unusual.  After private surgery we will phone you the following day and you will be given emergency contact details, which you should call if you think something may be wrong.



    Contact Details

    Address: Duchy Hospital, Penventinnie Lane, Truro, Cornwall. TR1 3UP.

    Secretary: Liz Venn

    Tel: 07500 847733

    WhatsApp: 07500 847733


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