Influence of botulinum toxin on myogenous facial pain

Objective. Can chronic pain of the masticatory muscles be positively affected by low dose injection of botulinum toxin (BTX-A)? Methods. Twenty patients suffering chronic myofacial pain were questioned and examined after injection of 25-50 U Dysport((R)) into the affected muscles over a period of 8 weeks. Results. Four weeks after injection of BTX-A patients reported a significant reduction of pain (p < 0.001, paired t-test. Power of performed test with alpha 0,050:1.000). Then the pain remained constant over the next 4 weeks. Concurrently a significant increase of mandubular range of movement was observed (p < 0,05, Wilcoxon signed rank test). Conclusions. Even though lacking placebo control the findings suggest that patients suffering chronic myofacial pain may benefit from injection of low dose BTX-A into the affected muscles.