This study continues the work already done investigating the use of botulinum type A toxin (Botox A) for relief of muscle pain. A specific Botox agent called Dysport® was used in patients with upper back pain. Dysport® has a much higher biologically active dosage compared to Botox®.
All patients had been diagnosed with a condition called myofascial pain syndrome (MPS). MPS is described as chronic muscle pain from shortened or contracted muscles. Trigger points (TrPs) are often part of the clinical picture. TrPs are areas of hyperirritable spots. When pressed or stimulated, TrPs cause a predictable pain pattern.
Patients included were men and women between the ages of 18 and 70 years. All had MPS with at least 10 TrPs present in the neck or upper back. Symptoms had been reported for at least six months.
Each patient was given a single injection of Dysport® into the 10 most painful TrPs. Pain level after five weeks was the main result measured. Change in pain intensity and number of pain-free days each week were also recorded. Results were compared to a placebo (control) group who had saline injections without the Botox.
The researchers report patients in the Dysport® group had greater pain relief at week five compared to patients in the placebo group. Pain intensity was less in the Dyport® group. The benefits of the injection lasted at least 12 weeks.
Patients receiving the Botox treatment had better pain relief throughout the course of the study. They said they would recommend this treatment to other patients with MPS.