Appraising a single-arm dry needling study before service adoption
The outpatient physiotherapy team is considering purchasing dry needling equipment for chronic neck pain. The clinic owner brings a study: 25 adults with chronic neck pain received four weekly dry needling sessions plus usual care. Pain on a 0–10 numeric rating scale fell from a mean of 7.1 to 4.0 immediately after treatment; the within-group change was statistically significant (p = 0.02). There was no control group, no blinding, and 6 participants were lost to follow-up. The authors conclude that dry needling is effective and should be adopted. The owner asks you, as the senior physiotherapist, to decide whether to introduce it. You have one colleague trained in dry needling and a limited budget.
1. Critically appraise the study’s design and interpret the p-value and the reported change.
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The study is a single-arm pre-post design with 25 participants, no control group, no blinding, and 6 lost to follow-up. That means we cannot separate treatment effect from natural history, regression to the mean, placebo, or concurrent usual care. The p-value of 0.02 indicates that a change this large would be unlikely if the true within-group change were zero, but it does not establish clinical importance or causation. The mean change of 3.1 points on a 0–10 scale may exceed a typical minimal clinically important difference for neck pain, often around 2 points, but without a confidence interval, a control group, or a responder analysis, we cannot judge precision or how many patients improved meaningfully. Attrition of 24% could bias the result. The authors’ conclusion that dry needling is effective and should be adopted is not supported by this design.
2. What additional evidence and local considerations would you need before adopting the service?
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I would look for systematic reviews or randomised controlled trials of dry needling for chronic neck pain, with blinding and adequate follow-up, and compare effect sizes and harms. I would check whether the technique is within our scope of practice and covered by indemnity, the training and competency of the colleague, and the consent process. Local considerations include cost of needles and equipment, sharps disposal, infection control, space, and time. I would also consider whether our patients are similar to the study population and whether we can collect our own audit data. A pilot with a defined protocol, adverse event monitoring, and pre-specified outcomes would be more defensible than adopting it immediately.
3. How would you explain your decision to the clinic owner?
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I would explain that the study is promising but does not provide enough evidence to justify a service change on its own. I would propose a small pilot: 12 weeks, agreed inclusion criteria, baseline and follow-up pain and function measures, adverse event recording, and a review before continuing. I would be clear that the p-value does not prove the treatment works and that the 3-point change could partly reflect natural improvement. I would offer to help search for higher-quality evidence and to evaluate the pilot. This balances the owner’s interest with patient safety and evidence-based practice.