What is the first-line treatment for anismus?

First-Line Treatment for Anismus

Biofeedback therapy is the first-line treatment for anismus, though it has limited therapeutic success with initial improvement rates of approximately 50% and long-term success rates of only 25-30%. 1, 2, 3

Understanding Anismus

Anismus (also called dyssynergic defecation or pelvic floor dyssynergia) is a functional defecation disorder characterized by:

• Paradoxical contraction or failure to relax the pelvic floor muscles during attempted defecation
• Often presents as chronic constipation with symptoms of obstructed defecation
• Diagnosis typically requires anorectal manometry, balloon expulsion test, defecography, and electromyography

Treatment Algorithm

First-Line Treatment: Biofeedback Therapy

• Recommended as initial treatment approach 1, 2, 3
• Typically administered 2 times per week for approximately 1 month 2
• Teaches patients to coordinate abdominal push efforts with pelvic floor relaxation
• Initial success rates: approximately 50% 2
• Long-term success rates: approximately 25-30% 2, 4
• Factors affecting success:
  • Duration of symptoms before treatment (longer duration predicts poorer outcomes) 3
  • Patients with symptoms >81 months show significantly worse response 3

Second-Line Treatment: Botulinum Toxin Type A (BTX-A) Injection

• Recommended when biofeedback fails after adequate trial (at least 3 sessions) 2, 5
• Injection into the puborectalis and external sphincter muscles 2, 5, 6
• Dosage: 6-15 units bilaterally under EMG guidance 5
• Initial success rates: 70-75% 2, 4
• Long-term success rates: 33-35% 2, 4
• May require repeat injections due to temporary effect 5
• Consider combining with continued biofeedback for better results 6

Third-Line Treatment: Surgical Intervention

• Consider only after failure of both biofeedback and BTX-A injection 4
• Partial division of puborectalis (PDPR) shows higher success rates:
  • Initial success: 95% 4
  • Long-term success (1 year): 70% 4
• Should be reserved for refractory cases due to invasive nature

Adjunctive Treatments

• Dietary modifications: increased fiber and water intake 7, 1
• Stool softeners to facilitate bowel movements
• Warm sitz baths for symptomatic relief 1
• Proper anal hygiene with water rather than toilet paper 1

Monitoring and Follow-up

• Assess response at 2-week intervals initially 1
• For BTX-A treatment, effects typically last 3-6 months; may require repeat injections 5
• Consider treatment failure if no improvement after 8 weeks of conservative management 1

Common Pitfalls to Avoid

• Inadequate trial of biofeedback (minimum 3 sessions recommended) 5
• Premature progression to invasive treatments
• Failure to identify associated pelvirectal disorders that may complicate treatment 3
• Not addressing dietary and lifestyle factors that contribute to constipation 1
• Discontinuing treatments prematurely before therapeutic effect is achieved 1

Special Considerations

• Extensive examination (defecography and manometry) before biofeedback is not mandatory as treatment failure is not necessarily related to associated pelvirectal disorders 3
• Combined approaches (BTX-A injection with continued biofeedback) may be more effective than single modalities for refractory cases 6