Objective: Up to 87% of patients with whiplash associated disorder (WAD) have some degree of muscle spasm that is contributory to both pain and dysfunction. Botulinum toxin A (BTX-A) produces prolonged muscle relaxation that is dose-dependent and can be easily targeted to affected muscles. BTX-A therapy may be an effective form of therapy offering an alternative or adjunct to conventional modalities. We investigated BTX-A as therapy in patients with WAD.
Methods: This randomized, double blind, placebo controlled study compares outcome measures in 26 patients with chronic neck pain (WAD-II chronic) subsequent to a motor vehicle accident. One-half of the patients received 100 units BTX-A, diluted in 1 ml saline, while the other half received just saline (1 ml). Five trigger points received 0.2 ml each of injectant via a 30 gauge needle. Outcome measures included total subjective neck, shoulder, and head pain based on visual analog scales; objective total range of neck motion (ROM), and the Vernon-Mior subjective function index. Followup assessments were carried out at 2 and 4 weeks post-treatment.
Results: Fourteen subjects receiving BTX-A and 12 receiving saline completed the study. The treatment group showed a trend toward improvement in ROM and reduction in pain at 2 weeks post-injection. At 4 weeks post-injection the treatment group was significantly improved from preinjection levels (p < 0.01). The placebo group showed no statistically significant changes at any post-treatment time. The Vernon-Mior scale revealed a trend to improvement for both groups.
Conclusion: BTX-A treatment of subjects with chronic WAD II neck pain resulted in a significant (p < 0.01) improvement in ROM and subjective pain compared to a placebo group, but only a trend to improvement in subjective functioning.