There are two things for PT’s to keep in mind with regard to dry needling. Before I proceed, let me say that I am not against dry needling. I simply believe PT’s should keep these two things in mind.
First, as physical therapists we have a history as a profession of seeking out and treating the primary cause of movement dysfunction leading to reduced activity. Musculoskeletal pain, tightness and spasm are a proximal cause of movement dysfunction leading to activity and should be treated. Dry needling proposes to treat these proximal causes which, if effective, would be considered an useful step towards allowing treatment of the primary cause (usually more distal, the cause that resulted in musculoskeletal pain, tightness and spasm in the first place). Of the two things to keep in mind about dry needling this is much less likely to be a problem. This recommendation is aligned with recommendations based on this systematic review in PTJ (here).
Second, it is well known that the placebo effect powerfully affects study findings. It is important to keep in mind that the more invasive an intervention is the stronger the placebo effect, particularly on pain (see here). This places a large requirement on studies aiming to demonstrate the effectiveness of dry needling. Studies cannot (or should not) simply provide control groups with non dry needling as a disparity in the invasiveness of the intervention can be an alternate explanation for findings. They must include sham dry needling - such as included in this very recent study (here) - which did not show a difference between dry needling and exercise vs. sham dry needling and exercise. Since they are concluding the null hypothesis is true, the power of the study is important. The study seems adequately powered but I have not done a power analysis to determine the exact power for the study (n = 80, 40 per group) (I don’t actually have access to the full paper). The point here is that the control group intervention is very important in studies of dry needling. A recent systematic review and meta - analysis (linked here) reports difficulty in comparing RCTs on dry needling based on the composition of and interventions used in the control group, particularly when pain or other subjectively reported (and hence more susceptible to the placebo effect) outcomes are reported. Further consideration should be made both with the design and conduct of trials as well as with future systematic reviews.
Now - a whole different discussion could be had about the placebo effect itself. After all, if the goal is to reduce pain, then why not take advantage of the placebo effect if it allows the patient to do more active therapy to address the more primary causal mechanisms? I cannot propose to answer this question here, perhaps ever, but pragmatically this could be considered based on risk/benefit, pros/cons. If anyone wants to write a post about the placebo effect let me know.