Anal Fissures

History and examination

Pain with defecation, which may be severe and persist for hours. Minor ano-rectal bleeding, usually noted as spotting on toilet paper. Associated with constipation, childbirth, and opioids.

An elliptical ulcer involving the lower third of the anus, running from the dentate line to the anal verge — generally midline, posterior (6 o’clock position). Severe pain on PR examination. If multiple fissures, suspect Crohn’s disease. A long-standing fissure often develops a sentinel skin tag.

Management

Disrupt the cycle of anal sphincter spasm to allow healing.

1. Conservative therapy, first-line: soften stools with a high-fibre diet (≥15g/day gives ~87% healing) and warm sitz baths after defecation.
2. Topical therapy if conservative measures aren’t enough: GTN ointment (Rectogesic) applied to the anal sphincter — place on a gloved finger and gently insert into the anal canal, 3–4 times daily — or a calcium channel blocker (topical nifedipine/diltiazem). CCBs are generally preferred over GTN given a lower side-effect burden — GTN causes headache in up to 20% of patients, often enough to cause discontinuation.
3. Botulinum toxin injection when topical therapy fails — a temporary sphincter relaxation, particularly favoured in Crohn’s disease or patients at high risk of incontinence (avoids the permanent risk of surgical sphincterotomy).
4. Surgery for chronic, treatment-refractory fissures:
   • Lateral internal sphincterotomy (LIS) — the surgical mainstay for chronic hypertonic fissures, but carries a real flatus/faecal incontinence risk (up to 17% transient, ~1% at 5 years) — beware permanent incontinence.
   • Fissurectomy with advancement anoplasty — preferred when the sphincter is hypotonic, or the patient is already at high incontinence risk.

Secondary fissures (associated with Crohn’s disease, malignancy, STI, or TB — suspect if atypical location, multiple fissures, or not healing as expected) need specialist work-up before any surgical intervention.