A prospective randomized controlled study of the role of botulinum toxin in whiplash-associated disorder.

OBJECTIVES: To investigate the effectiveness of botulinum toxin in preventing the development of chronic whiplash-associated disorder.

DESIGN: Prospective, randomized, placebo-controlled double-blind study.

SETTING: Regional Neurological Rehabilitation Centre with participants being at home.

SUBJECTS: Thirty-seven patients with whiplash-associated disorder who remained symptomatic two months after injury.

INTERVENTIONS: Patients were randomized to receive either 250 units botulinum toxin type A (Dysport) or placebo (normal saline). Four trigger points were injected with 0.625 mL of injectant.

OUTCOME MEASURES: Tenderness to palpation scores, visual analogue pain scale, Vernon-Mior Neck Pain and Disability Index and cervical range of motion. Follow-up assessments were carried out at four weeks and three months after treatment.

RESULTS: Twenty participants received botulinum toxin and 17 received placebo. Both groups showed a tendency towards improvement in pain scores, Vernon-Mior Index and range of motion at four weeks and three months, with the changes being more pronounced in the toxin group. The change in Vernon-Mior Index in the toxin group was both statistically and clinically significant (i.e. a change of score of > or = 5 from baseline to follow-up). Group comparisons did not meet statistical significance.

CONCLUSION: The improvements in outcome measures suggest that botulinum toxin type A may have a role to play in the management of whiplash-associated disorder but larger studies are required to clarify the situation.