 The efficacy of DN is also not completely clear, but shows a trend. One early literature review and meta-analysis concluded that DN was not significantly superior to placebo control in regards to pain decrease Tough. However, since then several systematic reviews with meta-analyses Tekin, Kietrys, Boyles determined that the evidence suggested that DN for trigger point-derived pain was likely to be the most effective approach, was superior in decreasing pain compared to stretching and percutaneous electric nerve stimulation and at least as effective as manual trigger point release and other needling treatments. One literature analysis supports the use of DN not only for its immediate, but also short-term effectiveness in reducing pain in patients with upper quarter myofascial pain syndrome Kietrys. 