Treatment of Spasmodic Torticollis (Cervical Dystonia)
Botulinum toxin injection into the affected neck muscles is the recommended treatment for spasmodic torticollis, with 62-95% of patients experiencing significant improvement in head position, pain relief, and quality of life. 1, 2
Primary Treatment: Botulinum Toxin Injection
Mechanism and Efficacy
- Botulinum toxin causes transient, nondestructive flaccid paralysis by inhibiting acetylcholine release from nerve terminals, thereby reducing muscle spasm 3
- Multiple studies demonstrate that 86-95% of patients experience significant improvement in abnormal head posture 1, 2
- Pain relief occurs in 84-89% of patients who present with pain 1, 2
- The beneficial effects typically last 2-4 months, requiring repeated injections every 3-4 months 1, 4, 5
Dosing and Administration
- Optimal dosing ranges from 200-400 mouse units per muscle 1
- Total doses typically range from 30-120 international units distributed across affected muscles 5, 6
- Primary target muscles include the sternocleidomastoid, splenius capitis, and trapezius muscles 1, 4
- Injecting two or more involved neck muscles is more effective than single-muscle injection 2
FDA Status and Safety Profile
- While not FDA-approved specifically for cervical dystonia in the provided drug label, botulinum toxin is widely used for this indication with extensive supporting evidence 7
- The FDA drug label indicates botulinum toxin is approved "to treat the abnormal head position and neck pain that happens with cervical dystonia (CD) in adults" 7
Common Adverse Effects and Management
Dysphagia (Most Common)
- Occurs after 44% of treatments but is severe in only 2% of cases 2
- Transient dysphagia reported in 22% of sessions in one series 1
- Reducing the concentration and total dose of toxin minimizes severe dysphagia 5
Other Side Effects
- Neck muscle weakness: 10% of sessions 1
- Voice weakness: occasional and transient 5
- Local pain at injection site: mild and transient 5
- All adverse effects are temporary and resolve spontaneously 1, 4, 5
Treatment Response Patterns
Expected Outcomes
- Improvement typically becomes apparent within 6 weeks of injection 5
- 93% of treatments result in some improvement, with 76% achieving moderate to excellent improvement 2
- Median duration of benefit is 9 weeks (range 2-4 months) 2, 5
- Treatment efficacy is maintained with subsequent injections in most patients 1
Non-Responders
- Only 2-7% of patients are consistent non-responders 1, 6
- Loss of efficacy after multiple treatments may indicate antibody formation (occurs in approximately 3 out of 5 patients who lose response) 2
- All torticollis subtypes (simple, combined, retrocollis, lateral collis) respond equally well 2
Clinical Pitfalls to Avoid
- Do not use overly concentrated solutions, as this increases the risk of severe dysphagia 5
- Adjust dose, distribution, and timing of injections to decrease adverse events 3
- Coexisting neurotic syndromes may worsen therapeutic outcomes 4
- After several injections, muscle atrophy and denervation potentials on EMG are expected findings 4
Long-Term Management
- Treatment can be safely administered in outpatient settings with minimal discomfort 3
- Repeated injections every 3-4 months maintain efficacy in the majority of patients 1, 4
- Long-term follow-up studies (up to 42 months) demonstrate sustained benefit with acceptable safety profile 2
- This represents the most effective available therapy for spasmodic torticollis compared to medications or surgical interventions 2