Study designs of evaluations included in the review
Double- or single-blind randomised controlled trials (RCTs) were eligible for inclusion. Only trials with 10 or more participants were eligible for inclusion. Open-label clinical trials, case series, case reports, reviews, expert opinions and abstracts were excluded. The included studies were double-blind RCTs; one study had a crossover design.
Specific interventions included in the review
Studies of BTA for myofascial TPs compared with active or inactive controls were eligible for inclusion. All included studies were of BTA compared with saline injection. The volume of BTA injected ranged from 0.05 to 6 mL, with BTA concentrations ranging from 5 to 150 U. Where reported, concurrent therapies included paracetamol, physical therapy, or a standardised regimen of amitriptyline, ibuprofen and propoxyphene-acetaminophen.
Participants included in the review
Studies of participants undergoing treatment for TP were eligible for inclusion. The definition of TP used varied between trials. Studies of patients treated for muscle spasm and pain with no mention of TP were excluded. The mean age of the participants ranged from 38.1 to 46.6 years. The duration of pain ranged from more than 6 months to a mean of 8.6 years. Where reported, 67% of the participants were female. Pain location was neck and shoulder, cervical and cervico-thoracic.
Outcomes assessed in the review
Outcomes eligible for inclusion were not clearly defined. The outcomes reported were use of rescue medication, pain, mood, range of motion and assessment of improvement. A variety of standardised and non-standardised measures were used.
How were decisions on the relevance of primary studies made?
One author read the retrieved abstracts and selected studies for inclusion. Reasons for study exclusion were reported in the review. Both authors subsequently read all of the included articles to check their eligibility.