Therapeutic use of botulinum toxin type A in treating neck and upper-back pain of myofascial origin: a pilot study. Efficacy and safety of a single botulinum type A toxin complex treatment (Dysport) for the relief of upper back myofascial pain syndrome: results from a randomized double-blind placebo-controlled multicentre study. A randomized, double-blind, prospective pilot study of botulinum toxin injection for refractory, unilateral, cervicothoracic, paraspinal, myofascial pain syndrome. The effect of small doses of botulinum toxin a on neck-shoulder myofascial pain syndrome: a double-blind, randomized, and controlled crossover trial.
To determine the efficacy of botulinum toxin type A (BTX-A) in treating neck and upper-back pain of myofascial origin.
                A randomized, double-blind, placebo-controlled pilot study.
                Outpatient physical medicine and rehabilitation clinic of a university-affiliated tertiary hospital.
                A total of 29 subjects enrolled from among 45 screened patients. No subject withdrawal due to serious adverse events occurred.
                Subjects were evaluated at baseline, received a 1-time injection of either BTX-A (treatment group) or saline (control group), and were followed up at 2 weeks and at months 1, 2, 3, 4, and 6.
                Visual analog scale (VAS) for pain, the Neck Disability Index (NDI), and the Medical Outcome Study 36-Item Short-Form Health Survey (SF-36).
                Improvements in the VAS and NDI scores were seen in the treatment group but were not significant when compared with the controls. Statistically significant improvements for the treatment group were seen in the SF-36 bodily pain (at months 2 and 4) and mental health (at month 1) scales but not in the other scales, nor in the summary measures. No serious adverse events were reported.
                Trends toward improvements in VAS and NDI scores of the BTX-A group are encouraging, but they were possibly due to a placebo effect and were not statistically significant. The BTX-A subjects, at certain time points, showed statistically significant improvements in the bodily pain and mental health scales of the SF-36 compared with controls. Our study had limited power and population base, but the results could be used to properly power follow-up studies to further investigate this topic. Botulinum type A toxin (BoNT-A) has antinociceptive and muscle-relaxant properties and may help relieve the symptoms of myofascial pain syndrome. In this study we evaluated the efficacy and tolerability of BoNT-A (Dysport) in patients with myofascial pain syndrome of the upper back. We conducted a prospective, randomized, double-blind, placebo-controlled, 12-week, multicentre study. Patients with moderate-to-severe myofascial pain syndrome affecting cervical and/or shoulder muscles (10 trigger points, disease duration 6-24 months) were randomized to Dysport or saline. Injections were made into the 10 most tender trigger points (40 units per site). The primary outcome was the proportion of patients with mild or no pain at week 5. Secondary outcomes included changes in pain intensity and the number of pain-free days per week. Tolerability and safety were also assessed. At week 5, significantly more patients in the Dysport group reported mild or no pain (51%), compared with the patients in the placebo group (26%; p=0.002). Compared with placebo, Dysport resulted in a significantly greater change from baseline in pain intensity during weeks 5-8 (p<0.05), and significantly fewer days per week without pain between weeks 5 and 12 (p=0.036). Treatment was well tolerated, with most side effects resolving within 8 weeks. In conclusion, in patients with upper back myofascial pain syndrome, injections of 400 Ipsen units of Dysport at 10 individualised trigger points significantly improved pain levels 4-6 weeks after treatment. Injections were well tolerated. In a randomized, double-blind study, two dosage strengths of botulinum toxin type A were compared with normal saline injected into symptomatic trigger points in the cervicothoracic paraspinal muscles.
                To compare the effect of botulinum toxin type A injections with that of normal saline to determine the former's usefulness in the management of neck pain and disability.
                The results of several studies have suggested that botulinum toxin type A may reduce pain associated with myofascial pain syndromes.
                Thirty-three participants were divided randomly to receive either 50 or 100 units of botulinum toxin type A, or normal saline. Patients were re-evaluated over a 4-month period by assessment of their pain and disability and pressure algometer readings, and then offered a second injection of 100 units of botulinum toxin type A.
                All three groups showed significant treatment effects as measured by a decline in the scores on the Neck Pain and Disability Visual Analogue Scale and an increase in the pressure algometer scores. Group differences were apparent only when the authors considered the number of patients who were asymptomatic as a result of the injections.
                Although no statistically significant benefit of botulinum toxin type A over placebo was demonstrated in this study, the high incidence of patients who were asymptomatic after a second injection suggests that further research is needed to determine whether higher dosages and sequential injections in a larger cohort might show a botulinum toxin type A effect. Myofascial pain syndrome is a common cause of muscular pain in the shoulder-neck region. Injections of large amounts of botulinum toxin A have been found to be beneficial for the alleviation of myofascial pain, but large doses of this toxin may cause paresis of the muscle and other adverse events. The aim of this work was to determine the effect of small doses (5 U) of botulinum toxin A (BTA) injected directly into the painful trigger points of the muscles, using a double-blind crossover technique.
                On the basis of the empirical criteria proposed for diagnosis of myofascial pain syndrome, 31 patients suffering from myofascial pain in the neck-shoulder region were studied. The patients received either botulinum toxin A or physiological saline injections on 2 occasions 4 weeks apart. The total dose varied from 15 to 35 U of botulinum toxin A [28+/- 6 U (mean+/- SD)]. The follow-up measurements were carried out at 4 weeks after each treatment. Neck pain and result of treatment were assessed with questionnaires. The pressure pain threshold was determined using a dolorimeter.
                Neck pain values decreased from 4.3+/- 2.4 to 3.3+/- 2.0 after saline injections and from 4.1+/- 2.1 to 3.3+/- 2.2 after botulinum toxin A. The pressure pain threshold values increased from 5.2+/-1.6 to 5.9+/-1.5 and from 5.7+/-1.6 to 5.9+/-1.6 after injections with saline and botulinum toxin A, respectively. No statistically significant changes in the neck pain and pressure pain threshold values occurred between the botulinum toxin A and saline groups. After the first injections, the subjective result of treatment was significantly (P=0.008) in favor of botulinum toxin A, and after the second injections, the subjective result was better for saline, but the difference was not statistically significant (P=0.098). There was no significant difference in the prevalence of side effects between saline and botulinum toxin A.
                Our study shows that there was no difference between the effect of small doses of botulinum toxin A and those of physiological saline in the treatment of myofascial pain syndrome.
There is inconclusive evidence to support the use of botulinum toxin in the treatment of MPS based on data from four studies with a total of 233 participants, which we considered adequate to be included in this review. Meta-analyses were not possible due to the heterogeneity between studies. We suggest that in future studies the same methodology to assess pain, a standardised dose of treatment, follow-up of at least four months (to observe the maximum/minimum curve of the drug effect) and appropriate data presentation should be used. More high-quality RCTs of botulinum toxin for treating MPS need to be conducted before firm conclusions on its effectiveness and safety can be drawn.