(HealthDay News) – Botulinum toxin type A (BoNT-A) injections are associated with a significant improvement in myofascial pain syndrome, according to a study presented at the annual meeting of the American Society of Anesthesiologists, held from Oct. 13 to 17 in Washington, D.C.

Jeffrey Loh, M.D., from the University of California Los Angeles in Santa Monica, and colleagues assessed the efficacy of BoNT-A for the treatment of myofascial pain syndrome in a single-center, double-blind, placebo-controlled trial involving 118 subjects with cervicothoracic muscle pain for more than eight weeks. Participants with a Visual Numerical Pain Score (VNS) greater than 4 were injected with BoNT-A and those with at least a 50 percent decrease in their VNS at six weeks post-injection were randomly allocated to receive either a second BoNT-A injection into affected muscles (29 patients) or a saline injection (25 patients). The groups were followed for 12 weeks.

The researchers found that, compared with placebo, patients who received a second BoNT-A injection experienced a significant reduction in the number of headaches per week. BoNT-A-treated patients also experienced significant improvements in quality-of-life parameters, including general activity, sleep, and enjoyment. They also had a significant reduction in the total number of posterior trigger points.

“At best, long-term benefit with traditional therapies is transient and unpredictable,” a coauthor said in a statement. “Botox may offer advantages over traditional therapies for myofascial pain syndrome due to its prolonged and sustained effects.”

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