BACKGROUND: Extracorporeal shockwave therapy (ESWT) has been used successfully in different musculoskeletal conditions, including pseudarthrosis and tendinopathies. However no randomized controlled trial are available about its use for chronic low back pain with myofascial pain syndrome (MPS). AIMS: The aim of the study was to evaluate the efficacy of radial ESWT (r - ESWT) in the treatment of MPS in the lumbar and gluteal regions. METHODS: The study was prospective, randomized, double-blind and placebo controlled. A total of 121 patients were enrolled and 46 patients were considered eligible based on inclusion and exclusion criteria (chronic low back pain, MPS lasting more than six months, DN4 < 4, VAS ≥ 4). In the first phase, all patients were treated with a standard multidisciplinary protocol for six weeks (tricyclic antidepressant associated with physical therapy). After this phase, patients were reassessed with previously used questionnaires, 31 patients had VAS ≥ 4 and moved to the r - ESWT phase. In the 2nd phase, they were randomized into 2 groups: active (n = 14) and control (n = 17). The patients underwent six ESWT sessions with an interval of one week between them. The parameters used in the radial shockwave device were: pulses = 1000 per trigger point or 2500 per muscle; frequency = 5 to 7 hertz; pressure = 3 bar (1st and 2nd sessions), 3.5 bar (3rd and 4th sessions), 4 bar (5th and 6th sessions). Evaluations were made after the first phase of conservative treatment and after ESWT (1.5, 3, 6 and 12 months). Pain intensity and functional disability were assessed using the VAS, Roland Morris Disability Questionnaire (RDQ), Oswestry Disability Index (ODI), Short-form McGill Pain Questionnaire (SF-MPQ). Trigger points were documented through thermography. RESULTS: Baseline characteristics of age, gender, VAS, RDQ, ODI, SF-MPQ were similar between groups. However, the duration of low back pain was significantly longer in the active r - ESWT group (p < 0.05).
Three, six and 12 months after r - ESWT, the percentage of patients who had greater than 50% improvement in VAS in the active group was significantly higher than in the control group (Fig. 2). At the 12nd months of follow-up, the active group had significantly improvement in the functional disability of low back pain according to ODI (Fig. 3). CONCLUSIONS: The r - ESWT provided a significant and lasting reduction in pain intensity from the third until 12th month of follow up, finding that suggests that its analgesic effect settles late and has long duration. Additionally, r - ESWT pro-vided improvement of the functionality according to the ODI at the 12th month follow up.

A PROSPECTIVE, COMPARATIVE, RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED STUDY ON THE EFFICACY OF RADIAL SHOCKWAVES IN THE TREATMENT OF MYOFASCIAL PAIN SYNDROME OF THE LUMBAR/GLUTEAL REGIONS