A 45-year-old man with chronic anal fissure at the posterior midline has failed topical glyceryl trinitrate and diltiazem over 3 months. The next recommended treatment is:
- A Lateral internal sphincterotomy (LIS)
- B Fissurectomy and fistulotomy
- C Botulinum toxin injection into the internal sphincter ✓
- D Manual anal dilation (Lord's procedure)
Explanation
Botulinum toxin injection into the internal anal sphincter is the recommended second-line treatment after topical pharmacotherapy failure for chronic anal fissure, achieving healing in approximately 70–80% of cases. Botulinum toxin causes temporary chemical sphincterotomy lasting 3–6 months, allowing fissure healing without permanent sphincter division. Lateral internal sphincterotomy (LIS) has the highest healing rate (>90%) but carries a 5–10% risk of fecal incontinence and is typically reserved after botulinum toxin failure. Lord's procedure (anal dilation) is now abandoned due to high incontinence risk.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.