Botulinum Type A Toxin Complex for the Relief of Upper Back Myofascial Pain Syndrome: How Do Fixed-Location Injections Compare with Trigger Point-Focused Injections?
Pain Medicine, 06/22/2011
Benecke R et al. – Fixed–location treatment with BoNT–A of patients with upper back myofascial pain syndrome did not lead to a significant improvement of the main target parameter in week 5 after treatment. Only in week 8 were significant differences found. Several secondary parameters, such as physicians' global assessment and patients' global assessment, significantly favored BoNT–A over placebo at weeks 8 and 12.Methods
- Patients with moderate–to–severe myofascial pain syndrome affecting cervical and/or shoulder muscles (10 trigger points, disease duration 6–24 months) and moderate–to–severe pain intensity were randomized to BoNT–A (N = 81) or saline (N = 72).
- Patients received treatment into 10 predetermined fixed injection sites in the head, neck, and shoulder (40 units of BoNT–A per site or saline, a total of 400 units of BoNT–A).
- The primary efficacy outcome was the proportion of patients with mild or no pain at week 5 (responders).
- Secondary outcomes included changes in pain intensity and the number of pain–free days per week.
- At week 5, 49% (37/76) of BoNT–A patients and 38% (27/72) of placebo patients had responded to treatment (P = 0.1873).
- Duration of daily pain was reduced in the BoNT–A group compared with the placebo group from week 5, with statistically significant differences at weeks 9 and 10 (P = 0.04 for both).
- Treatment was well tolerated.