A chronic fissure is maintained by spasm of the internal sphincter. When conservative treatment fails, surgery reduces the spasm — with botox injection or lateral internal sphincterotomy (LIS) — restoring blood supply so the fissure heals.
What does it involve?
The aim is to relax the hypertonic internal sphincter that prevents healing. This is achieved either temporarily (botox) or permanently by dividing a small part of the sphincter (LIS).
When is it needed?
It is indicated for a chronic fissure that has not responded to conservative treatment (ointments, stool regulation). Another pathology is always excluded first.
Preparation
A proctological assessment confirms the chronic fissure and excludes other causes. A short preparation and choice of technique/anaesthesia follow.
How it's done
The choice is individualised: botox injection (no cut to the sphincter) or lateral internal sphincterotomy — dividing a small part of the internal sphincter to reduce spasm. It is done as a day case.
Botox injection
Temporary relaxation of the sphincter with no cut — avoids any risk to continence.
Lateral internal sphincterotomy
Division of a small part of the internal sphincter — high rates of definitive healing.
Advancement flap
In special cases, covering the fissure with healthy tissue without cutting the sphincter.
Recovery
Relief from pain is usually rapid. Discharge is the same day, with sitz baths, stool regulation and local care.
Risks & outcomes
Lateral internal sphincterotomy has high healing rates. The risk of mild continence disturbance is small with a careful, measured technique; botox avoids it but lasts less long.
Frequently asked questions
Will my continence be affected?
With a careful, measured sphincterotomy the risk is small. Botox avoids cutting the sphincter altogether and is an alternative in selected patients.
Why won't the fissure heal on its own?
Sphincter spasm reduces blood supply to the area and prevents healing. Reducing the spasm breaks this vicious cycle.
Is the operation painful?
Relief from the fissure pain is usually rapid. Post-operative discomfort is mild and easily controlled.
Will I stay in hospital?
No — it is done as a day case with return home the same day.