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?
It addresses a chronic anal fissure that has not healed with conservative treatment. The core problem is internal sphincter spasm, which keeps blood supply low and prevents healing; treatment targets exactly this spasm.
When is it needed?
Surgical/interventional treatment is considered when conservative treatment (stool regulation, topical relaxants, sitz baths) fails in a chronic fissure. Other causes (e.g. inflammatory bowel disease) are always excluded when the picture is atypical.
Preparation
A proctological assessment confirms the diagnosis and excludes underlying pathology. Counselling on the options and risk profile (particularly regarding continence) is essential before the decision.
How it's done
Lateral internal sphincterotomy is the most effective, definitive technique: a controlled division of part of the internal sphincter that relieves the spasm and allows healing, with very high cure rates. Alternatively, a botox injection temporarily relaxes the sphincter — a reversible option with a lower risk of continence disturbance, useful in selected patients.
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
The procedure is usually a day case. Pain relief is relatively quick; sitz baths, stool regulation and local care are advised until full healing.
Risks & outcomes
The main concern with sphincterotomy is a mild, usually transient continence disturbance (mainly to flatus); it is minimised by a correct, limited division and careful patient selection. The fissure may rarely recur.
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.