What are the evaluation and treatment options for an anal fissure?

Evaluation and Treatment of Anal Fissures

The first-line evaluation for anal fissures should include assessment of location, number, and characteristics of the fissure, with conservative management as initial treatment including stool softeners, topical calcium channel blockers, increased fiber intake, and sitz baths. 1

Diagnosis and Evaluation

Clinical Presentation

• Pain with defecation (typically more severe than hemorrhoids)
• Bright red bleeding (present in 71.4% of patients)
• Anal spasm and fear of bowel movements

Physical Examination

• Visual inspection of the anus and perianal area
• Gentle digital examination (may be deferred if too painful)
• Assessment of fissure location:
  • 90% are posterior midline
  • 10% of women and 1% of men have anterior fissures
  • Warning sign: Lateral or multiple fissures require investigation for underlying conditions such as inflammatory bowel disease, STIs, anorectal cancer, tuberculosis, or leukemia 1

Treatment Algorithm

Step 1: Conservative Management (First-line)

• Stool softeners to prevent constipation
• Dietary modifications:
  • Increase fiber (goal: 30-40g daily)
  • Increase water intake (at least 8 glasses daily)
• Topical treatments:
  • Calcium channel blockers (2% diltiazem ointment) - preferred due to higher efficacy (65-95% healing rates) and fewer side effects than nitrates 1
  • Moisturizing agents (petroleum jelly or zinc oxide) as protective barriers
• Pain management:
  • Warm sitz baths for symptomatic relief
  • Oral analgesics (acetaminophen, ibuprofen) for breakthrough pain

Step 2: If No Improvement After 4-6 Weeks

• Botulinum toxin injection:
  • High cure rates (75-95%)
  • Low morbidity profile
  • Effects last 3-6 months; may require repeat injections 1
• Consider platelet-rich plasma (PRP) injections:
  • Recent evidence (2023) shows significant improvement in healing rates (96% vs 66% at 6 months) and pain reduction compared to topical treatments alone 2
  • Particularly effective for chronic anal fissures

Step 3: Surgical Management (For Treatment Failures)

• Lateral Internal Sphincterotomy (LIS):
  • Gold standard surgical treatment with rapid and effective results 1, 3
  • Consider for:
    • Chronic or complicated fissures
    • Acute fissures with severe pain
    • Recurrent fissures despite optimal medical treatment
  • Caution: Carries risk of permanent minor sphincter impairment 1

Treatment Response Assessment

• Evaluate response at 2-week intervals initially
• Consider treatment failure if no improvement after 8 weeks of conservative management 1

Common Pitfalls to Avoid

1. Misdiagnosing hemorrhoids as the cause without proper examination
2. Failing to recognize atypical presentations requiring further investigation
3. Using manual anal dilatation (no longer recommended) 3
4. Inadequate trial of conservative treatment
5. Premature progression to invasive treatments
6. Not addressing dietary and lifestyle factors
7. Discontinuing treatments prematurely 1

Special Considerations

• While pharmacological therapy has lower healing and higher relapse rates than surgery, it avoids permanent alterations in continence 4
• Surgery may be offered first to patients without incontinence risk factors who have severe pain and accept a small risk of incontinence 4
• The risk of incontinence after LIS may have been overemphasized in the past 5
• Forcible uncalibrated anal dilatation is no longer recommended 3