Treatment of Anal Fissure
Start with conservative management for all acute anal fissures, as approximately 50% heal within 10-14 days with dietary modifications alone, and reserve surgery only for chronic fissures that fail 8 weeks of medical therapy. 1
First-Line Conservative Treatment (All Patients)
All patients with anal fissures should receive dietary and lifestyle modifications as the foundation of treatment. 2, 1 This includes:
- Fiber supplementation to soften stools and reduce mechanical trauma 1
- Increased oral fluid intake to maintain soft stool consistency 2
- Warm sitz baths 2-3 times daily to relax the internal anal sphincter 2, 1
- Topical analgesics (such as lidocaine) for pain control 1
Pain relief is critical because it breaks the pain-spasm-ischemia cycle that perpetuates the fissure. 3 About 50% of acute fissures will resolve with these measures alone within 10-14 days. 2, 1
Second-Line Pharmacological Treatment
If conservative measures fail after 2 weeks, add topical calcium channel blockers as the preferred pharmacological treatment. 1
Calcium Channel Blockers (Preferred)
Use topical nifedipine 0.3% with lidocaine 1.5%, applied three times daily for at least 6 weeks. 3 This combination achieves:
- Healing rates of 65-95% 1, 3
- Pain relief typically within 14 days 1, 3
- Minimal side effects compared to alternatives 3
- Excellent cost-effectiveness 3
The mechanism works by blocking calcium channels in vascular smooth muscle, reducing internal anal sphincter tone and increasing blood flow to the ischemic ulcer. 3
Alternative: Glyceryl Trinitrate (Less Preferred)
Glyceryl trinitrate ointment can be used but has significant limitations:
- Lower healing rates of only 25-50% 1
- Headaches occur in up to 77% of patients 4, 5
- High recurrence rates (67% at 9 months for chronic fissures) 5
One study found no benefit of nitroglycerin over placebo when combined with conservative measures. 6
Botulinum Toxin Injection
Botulinum toxin injection achieves cure rates of 75-95% with low morbidity and should be considered for patients at high risk of incontinence. 1, 7 However, the optimal injection location remains controversial. 1
Surgical Treatment
Reserve lateral internal sphincterotomy exclusively for chronic fissures (>8 weeks duration) that fail medical management, or acute fissures with severe disabling pain. 1, 8
Indications for Surgery
- Chronic fissures non-responsive after 8 weeks of conservative management 1
- Acute fissures with severe, disabling pain requiring faster relief 4
- Recurrent fissures despite optimal medical therapy 8
Surgical Technique
Lateral internal sphincterotomy is the gold standard surgical procedure with:
- Healing rates exceeding 95% 7, 8
- Recurrence rates of only 1-3% 7
- Faster pain relief compared to medical therapy (70% at 2 weeks vs 40% with nitroglycerin) 4
Critical Surgical Pitfall
Never perform manual dilatation—it is strongly contraindicated due to high risk of permanent incontinence. 2, 1, 3 This technique is no longer recommended. 8
Atypical Fissures Requiring Further Evaluation
Evaluate for underlying conditions if the fissure is not in the posterior midline, is multiple, or lateral. 2, 1 Consider:
- Inflammatory bowel disease (Crohn's disease, ulcerative colitis) 2, 1
- Sexually transmitted infections (HIV, syphilis, herpes) 2
- Anorectal cancer 2
- Tuberculosis 2, 1
Perform endoscopy, CT, MRI, or endoanal ultrasound only when these conditions are suspected. 2
Signs of Chronicity
Chronic fissures demonstrate:
- Sentinel skin tag 1
- Hypertrophied anal papilla 1
- Visible internal sphincter muscle fibers 1
- Fibrosis at the fissure base 1
Treatment Algorithm Summary
- Weeks 0-2: Conservative management (fiber, fluids, sitz baths, topical analgesia) for all patients 2, 1
- Weeks 2-8: Add topical nifedipine 0.3% with lidocaine if no improvement 1, 3
- After 8 weeks: Consider botulinum toxin injection or lateral internal sphincterotomy for persistent chronic fissures 1, 7
- Exception: Proceed directly to surgery for acute fissures with severe disabling pain 4, 8