This study assessed the effectiveness of botulinum toxin A injected in five cervical trigger points as treatment of chronic headaches stemming from a whiplash injury. Twenty-six patients, (11 men and 15 women, between 29 and 75 years old), completed the study. Patients were divided into a group of 14 who were treated with a dilution of botulinum toxin A, and a group of 12 who received placebo treatment (saline injections).
Follow-up assessments occurred at two and four weeks post-treatment. The outcome measures used were subjective head pain and objective range of neck motion. The treatment group showed reduction in pain and improved range of motion at the two-week follow-up. At the time of the four-week assessment, 11 of 14 in the treatment group showed significant improvement in both range of motion and pain as compared to pre-treatment levels. The placebo group showed no improvement on either outcome measure at the four-week assessment, although a portion of the placebo group reported improvement in pain at the two-week follow up. None of the patients reported any shoulder or neck muscle weakness or other side effects.
The authors write:
"This study offers no definitive insight into the pathophysiology of chronic cervical- associated headache but does demonstrate at least a short-term response of this condition to BTX-A trigger point injections in 11 of 14 subjects treated. This positive response is clinically similar to that observed in reports of temporomandibular dysfunction, tension headache, blepharospasm, and dystonias. It is, therefore possible that peripheral pain in these and other conditions shares a common pathology within myofascial tissues."
Due to the small sample size, and brief follow-up period no specific conclusions can be drawn from this study, but results do suggest that further research into the effectiveness of this therapy is justified.
Freund B, Schwartz M. Treatment of chronic cervical-associated headache with botulinum toxin A: A pilot study. Headache 2000;40:231-236.