Needling therapies in the management of myofascial pain of the masticatory muscles: A network meta-analysis of randomised clinical trials

Objective A network meta-analysis (NMA) of randomised clinical trials (RCTs) was performed aiming to compare the treatment outcome of dry needling, acupuncture or wet needling using different substances in managing myofascial pain of the masticatory muscles (TMD-M). Method An electronic search was undertaken to identify RCTs published until September 2019, comparing dry needling, acupuncture or wet needling using local anaesthesia (LA), botulinum toxin-A (BTX-A), granisetron, platelet-rich plasma (PRP) or passive placebo versus real active placebo in patients with TMD-M. RCTs meeting the inclusion criteria were stratified according to the follow-up time: immediate post-treatment to 3 weeks, and 1 to 6 months post-treatment. Outcome variables were post-treatment pain intensity, increased mouth opening (MMO) and pressure threshold pain (PPT). The quality of evidence was rated according to Cochrane's tool for assessing risk of bias. Mean difference (MD) was used to analysed via frequentist NMA using Stata software. Results Twenty-one RCTs involving 959 patients were included. The quality of evidence of the included studies was low or very low. There was significant pain decrease after PRP when compared to an active/passive placebo and acupuncture. There was a significant improvement of MMO after LA (MD = 3.65; CI: 1.18-6.1) and dry needling therapy (MD = 2.37; CI: 0.66-4) versus placebo. The three highest ranked treatments for short-term post-treatment pain reduction in TMD-M (1-20 days) were PRP (95.8%), followed by LA (62.5%) and dry needling (57.1%), whereas the three highest ranked treatments at intermediate-term follow-up (1-6 months) were LA (90.2%), dry needling (66.1%) and BTX-A (52.1%) (all very low-quality evidence). LA (96.4%) was the most effective treatment regarding the increase in MMO followed by dry needling (72.4%). Conclusion Based on this NMA, one can conclude that the effectiveness of needling therapy did not depend on needling type (dry or wet) or needling substance. The outcome of this NMA suggests that LA, BTX-A, granisetron and PRP hold some promise as injection therapies, but no definite conclusions can be drawn due to the low quality of evidence of the included studies. This NMA did not provide enough support for any of the needling therapies for TMD-M.