Anal Fissure Surgery

Anal Fissure Surgery

Surgical intervention is required if:

An anal fissure persists more than six weeks


Topical ointments fail to provide enough relaxation of the internal anal sphincter for the fissure to heal.

1. Botox injection – Botulinum toxin A

  • A 3ml injection containing up to 100 units of Botox is injected into the internal anal sphincter
  • Although this can be done as an office procedure, it is best done under general anaesthetic which also allows better examination of the anus +/- any other required procedures such as debridement (cleaning-up) of the fissure.
  • Botox works by relaxing the internal sphincter muscle for up to 3 months allowing the fissure to heal
  • Botox is expensive ($500-$600) but may be covered at least partially by private health funds. Please discuss this with your health fund.

2. Lateral sphincterotomy:

The lower part of the internal anal sphincter may be divided (up to one third of the muscle) to provide permanent relaxation of the muscle allowing for healing of the fissure and prevention of recurrence. This is the most successful treatment for an anal fissure.

What are the risks of surgery?

Significant bleeding is rare following a lateral sphincterotomy.

Infection is rare following a lateral sphincterotomy or Botox injection.

Botox can cause temporary incontinence of flatus in up to 15% of patients. However, this is usually only mild and lasts 3 months at the most. More significant incontinence is possible but rare and temporary.

The risk of incontinence following a lateral sphincterotomy is about 3% but is permanent.

Before surgery

Fast from midnight for a morning procedure OR from 7am for an afternoon procedure.

You will be contacted by the hospital the day before your procedure to let you know what time to come in. This is usually 1-2 hours before your procedure to allow for the hospital check-in procedures.

After surgery

Following a lateral sphincterotomy, bleeding is usually minimal but can last for a few days. This is especially so if the fissure is debrided (cleaned up)

Pain from the anal fissure should gradually decrease but will persist until the fissure heals which usually takes 6 weeks.

You should not require any more pain-killers than you did prior to surgery.

If the fissure is debrided, you may experience slightly more pain.

You should take regular Panadol (as long as there are no medical reasons for you not to take it such as an allergic reaction or liver disease).

Non-steroidal anti-inflammatory medication such as Neurofen and Voltaren can also help with pain and inflammation but should be taken on a full stomach. Take these for the first 3-5 days as required.

Stronger pain killers such as opioid anaelgesics (Endone, Codeine) may help in the first couple of days but should be taken sparingly as they can cause constipation which results in more pain when opening your bowels.

It is very important to maintain soft stools after surgery. This is done by having an adequate intake of fluid and fibre (see Prevention of constipation) as well as taking regular Movicol (1 sachet 1-3 times a day).

Laxatives such as lactulose or coloxyl are not advisable as diarrhoea can worsen the pain. The aim is to have soft stools NOT loose watery stools.

It is important to maintain soft stools at least until the fissure heals.

The aim of the procedure is to relax the internal anal sphincter.

After a Botox injection, continuing to use Rectogesic ointment may improve the likelihood of healing the anal fissure.

Topical Rectogesic ointment 2-3 times a day. This is an over-the-counter ointment that should be applied into the first 1-2cm of the anus. The easiest way to do this is to wear a disposable non-sterile glove (plastic food-handling gloves are ok) then apply 1.5cm of the ointment using your index finger.

This is not usually required after a lateral sphincterotomy

These are an excellent way of relieving the pain especially after opening your bowels. You should put a handful of salt into a shallow bath of warm water and sit in it for 15 minutes. This is both soothing and acts as an antiseptic.

There are no dressings apart from a pad that collects the post-operative blood. You may need to wear a pad for 2-3 days to prevent staining your underpants.

Ladies’ sanitary pads work well for this purpose and can be used by men and women.

You will be discharged home the same day

Follow up with your surgeon is usually within 4 weeks of your operation. You will be given an appointment before leaving the hospital. If, however, your operation finishes after hours, you will need to contact the rooms for a follow up appointment.