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Threads: #1 Neck Pain

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Zhelnov P. Threads: #1 Neck Pain. A critical appraisal and evidence-dissemination assessment of ‘Hu T, Long Y, Wei L, Zheng Y, Tong Y, Yuan M, Liu C, Wang X, Lin Y, Guo Q, Huang J, Du L. The Underappreciated Placebo Effects and Responses in Randomized Controlled Trials on Neck Pain: A Systematic Review With Meta-analysis. Arch Phys Med Rehabil. 2023 Jul;104(7):1124-1131. doi: 10.1016/j.apmr.2022.10.013. Epub 2022 Nov 20. PMID: 36417969’. Zheln. 2023 Jul 13;27(1):t1e3. URI:

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  • Zheln conducted a systematic search and evidence selection based on predefined criteria.
  • As a result, Zheln selected and critically appraised a recent systematic review of evidence with large social and practical importance for people suffering from neck pain and anyone involved in their care.
  • Evidence shows that the placebo effect is a major contributor to the treatment effect of various non-operative interventions for nonspecific neck pain (with or without neural involvement).
  • Despite its importance, this evidence nor the issue itself is largely not covered online.

Enter Zheln Threads

A Zheln Threads process consists of three stages:

  • Evidence Selection
  • Evidence Appraisal
  • Evidence Dissemination Assessment

🎉 I am excited to announce that, in order to achieve unparalleled transparency, this Zheln Threads process in its entirety is Written in Stone.

Evidence Selection

Systematic review selected for appraisal:

Hu T, Long Y, Wei L, Zheng Y, Tong Y, Yuan M, Liu C, Wang X, Lin Y, Guo Q, Huang J, Du L. The Underappreciated Placebo Effects and Responses in Randomized Controlled Trials on Neck Pain: A Systematic Review With Meta-analysis. Arch Phys Med Rehabil. 2023 Jul;104(7):1124-1131. doi: 10.1016/j.apmr.2022.10.013. Epub 2022 Nov 20. PMID: 36417969

Zheln search and selection are based on the original Zheln protocol. The procedure itself has evolved since the protocol publication, but the search query and the selection criteria have remained basically the same:

  • Participants/population: Humans. COVID-19 populations are excluded to avoid duplication of research and focus shift.
  • Intervention(s), exposure(s): Any intervention into a human life.
  • Comparator(s)/control: Any intervention into a human life.
  • Main outcome(s): Any practice-important and question-relevant outcome.

Evidence Appraisal

Zheln Review Appraisal in 10 Steps:

  1. ✅ Downloaded from the PubMed Systematic Subset Daily Updates
  2. ✅ Meets Shojania & Bero 2001 True Positive Criteria for Systematic Reviews by Either Title or Abstract?
  3. ✅ Full Text or Other Reports Collected by Zheln
  4. ✅ Generates Pragmatic Evidence Directly Relevant to Evidence-Based Practice
  5. ✅ Is Not Duplicate
  6. ✅ Passed Reproducibility Check
  7. ✅ Does Not Have Critical Conduct Flaws
  8. ✅ Liked by Zheln
  9. ✅ Practical Implications Summarized by Zheln
  10. ✅ Appraisal Published

The practical implication is that the placebo effect is a major contributor to the treatment effect of various non-operative interventions for nonspecific neck pain (with or without radiculopathy).

The systematic review does not appear to be duplicate at a quick glance. Upon quick PubMed and Google searches, no review seems to be covering the whole of neck pain treatment with a focus on the placebo effect.

However, a similar systematic review was published recently by Plener et al., covering only conservative treatment and only radiculopathic cervical pain. Unfortunately, it is paywalled, so I was unable to look into it and gain insights.

The review appears to be well-conducted overall.

The authors searched all the most important databases:

  • MEDLINE (PubMed)
  • EMBASE (Ovid)
  • Physiotherapy Evidence Database (PEDro)
  • World Health Organization International Clinical Trials Registry Platform

This randomized trial by Ceniza-Bordallo et al., published in 2019, which I casually came across on the first page of a Google for (neck pain placebo), was not included in Hu’s review, and I could not check if it was in the excluded because the authors had not reported the list of exclusions. Alternatively, maybe the search strategy did not capture this trial (this trial appears not to be indexed in PubMed, and the authors only reported their PubMed strategy, so I could not check). Overall, it looks like a good search strategy.

Another relevant trial, by Jones et al., has just been published and was unavailable to Hu et al. at the time of their searches.

Just as a remark, no trials of surgical treatments were eventually included in the Hu’s review, although those could have been eligible if had a placebo group. Five randomized trials of surgery vs. non-surgery are known to me at this point, none of which includes a placebo or no-treatment group:

  1. Kadanka Z, Bednarík J, Vohánka S, Vlach O, Stejskal L, Chaloupka R, Filipovicová D, Surelová D, Adamová B, Novotný O, Nemec M, Smrcka V, Urbánek I. Conservative treatment versus surgery in spondylotic cervical myelopathy: a prospective randomised study. Eur Spine J. 2000 Dec;9(6):538-44. doi: 10.1007/s005860000132. PMID: 11189924; PMCID: PMC3611417.

    With a follow-up study:

    Kadaňka Z, Bednařík J, Novotný O, Urbánek I, Dušek L. Cervical spondylotic myelopathy: conservative versus surgical treatment after 10 years. Eur Spine J. 2011 Sep;20(9):1533-8. doi: 10.1007/s00586-011-1811-9. Epub 2011 Apr 26. PMID: 21519928; PMCID: PMC3175900.

  2. Persson LC, Carlsson CA, Carlsson JY. Long-lasting cervical radicular pain managed with surgery, physiotherapy, or a cervical collar. A prospective, randomized study. Spine (Phila Pa 1976). 1997 Apr 1;22(7):751-8. doi: 10.1097/00007632-199704010-00007. PMID: 9106315.
  3. Cesaroni A, Nardi PV. Plasma disc decompression for contained cervical disc herniation: a randomized, controlled trial. Eur Spine J. 2010 Mar;19(3):477-86. doi: 10.1007/s00586-009-1189-0. Epub 2009 Nov 10. PMID: 19902277; PMCID: PMC2899766.
  4. van Geest S, Kuijper B, Oterdoom M, van den Hout W, Brand R, Stijnen T, Assendelft P, Koes B, Jacobs W, Peul W, Vleggeert-Lankamp C. CASINO: surgical or nonsurgical treatment for cervical radiculopathy, a randomised controlled trial. BMC Musculoskelet Disord. 2014 Apr 14;15:129. doi: 10.1186/1471-2474-15-129. PMID: 24731301; PMCID: PMC4012146.
  5. Taso M, Sommernes JH, Kolstad F, Sundseth J, Bjorland S, Pripp AH, Zwart JA, Brox JI. A randomised controlled trial comparing the effectiveness of surgical and nonsurgical treatment for cervical radiculopathy. BMC Musculoskelet Disord. 2020 Mar 16;21(1):171. doi: 10.1186/s12891-020-3188-6. PMID: 32178655; PMCID: PMC7076994.

The first two come from a relevant systematic review by Nikolaidis et al. (2010). I have also found a follow-up study for Kadaňka’s trial, but I am not sure if anyone looked at its data. Cesaroni et al. was published later and then covered by the review by van Middelkoop et al. (2013). I have found the remaining trials during this research, and van Geest et al. is only a protocol, probably with no results published.

Verhagen et al. (2013) found 39 randomized trials of surgery for cervical conditions, but they only looked at the comparison of various surgical techniques between each other (and have not found any evidence of differences whatsoever). Astur et al. (2022) found as many as 65 systematic reviews covering surgical treatment of cervical conditions, but it is unclear how many of those also included nonrandomized trials or found any new randomized trials having a placebo or non-treatment control group.

The limitations of the evidence include the high risk of statistical bias in most of the trials included as well as evidence of missing data both within and across trials. All of this means that the effect estimates could be even less extreme in reality.

That said, the finding that the placebo effect is a major contributor to the treatment outcomes in neck pain is likely to stand.

Evidence Dissemination

In Summary:

Neither the review nor the underlying evidence nor the topic of placebo in neck pain have been widely discussed or disseminated online.

The current most popular resources on neck pain treatment for the general audience do not mention placebo.

After looking on Google and Altmetric, I identified no coverage of the given review in any media except for Twitter so far. The Twitter coverage is 30 tweets as of now, which mostly are retweets. As of now, the Altmetric score is 19, which placed the review in the top 10% of all research outputs ever tracked by Altmetric (#1,792,769 of 24,004,724 outputs).

The top neck-pain-related webpages retrieved by Google did not mention placebo.

Google’s disease info snippet and Related questions did not mention placebo or its contribution to the actual observed effects of the treatment for neck pain, nor did Wikipedia or the websites of reputable clinics (Mayo Clinic, Cleveland Clinic, Harvard Health Publishing), popular portals (Spine-Health), and government authorities (NHS).

Accidentally, I came across links falsely claiming they lead to evidence whereas in fact they do not (MedicalNewsToday, The University of Sydney News).

Also, on MedicalNewsToday, some external links leading to scientific articles are marked with a tick and a label Trusted Source whereas in fact the articles themselves are not checked, just the journal or resource, which in itself says little about the trustworthiness of the article.

ChatGPT (Free Research Preview. May 24 Version) did not mention the importance of the placebo effect in its overview of neck pain treatment:

User: what is important to know for the general public about the treatment of neck pain?

ChatGPT: When it comes to the treatment of neck pain, there are several important points that the general public should be aware of:

1. Identify the cause: Neck pain can have various causes, including muscle strain, poor posture, injury, arthritis, or underlying medical conditions. It is crucial to identify the underlying cause of your neck pain to determine the most appropriate treatment.
2. Consult a healthcare professional: If you experience persistent or severe neck pain, it is advisable to consult a healthcare professional, such as a primary care physician, chiropractor, or physical therapist. They can evaluate your condition, provide a diagnosis, and recommend appropriate treatment options.
3. Rest and gentle movement: In many cases, rest and avoiding activities that worsen the pain can help alleviate neck discomfort. However, prolonged immobilization can be counterproductive. Gentle neck exercises and stretches recommended by a healthcare professional can help improve flexibility and strength, promoting healing and reducing pain.
4. Good posture: Maintaining good posture throughout the day is important for neck health. Avoid prolonged periods of slouching or craning your neck forward while using electronic devices. Ensure that your workstation is ergonomically designed to support proper posture.
5. Heat and cold therapy: Applying heat or cold therapy can provide temporary relief for neck pain. Cold packs can help reduce inflammation, while heat packs or warm showers can help relax tense muscles. Alternate between the two as needed, but avoid applying heat or cold directly to the skin to prevent burns or frostbite.
6. Over-the-counter pain relief: Non-prescription pain medications like acetaminophen (Tylenol) or nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) can be effective in reducing mild to moderate neck pain. However, always follow the recommended dosage and consult a healthcare professional if you have any concerns or existing medical conditions.
7. Physical therapy: For persistent or more severe neck pain, a healthcare professional may refer you to a physical therapist. They can provide targeted exercises, manual therapy, and other modalities to alleviate pain, improve range of motion, and strengthen the neck and supporting muscles.
8. Ergonomic adjustments: Making ergonomic adjustments to your workspace, such as using an ergonomic chair, adjusting the height of your computer monitor, and using a supportive pillow, can help reduce neck strain and promote better posture.
9. Stress management and relaxation techniques: Emotional stress and tension can contribute to neck pain. Engaging in stress management techniques such as deep breathing exercises, meditation, yoga, or other relaxation techniques can help reduce overall stress levels and alleviate neck pain.
10. Lifestyle modifications: Adopting a healthy lifestyle can contribute to overall well-being and help prevent or manage neck pain. Maintaining a balanced diet, engaging in regular physical activity, managing weight, and avoiding smoking can all promote neck health.

Remember, these points provide general guidance, but each individual's situation is unique. It's important to consult with a healthcare professional for personalized advice and treatment options based on your specific condition and medical history.

When prompted directly, ChatGPT provided a good overview of the placebo effect in general and in the treatment of neck pain in particular, without a clear focus on the contribution of the placebo effect to the actual treatment effects. As is to be expected of it, ChatGPT does not cite any sources.

User: what can you tell about the placebo effect with regard to the treatment of neck pain?

ChatGPT: The placebo effect refers to the phenomenon in which a patient experiences a perceived improvement in their symptoms or condition after receiving an inactive treatment or intervention that is presented as an active treatment. In the context of neck pain, the placebo effect can play a role in the perception of pain relief and overall treatment outcomes.

Studies have shown that placebos can have a notable impact on pain management, including neck pain. When individuals believe they are receiving a genuine treatment, even if it is a placebo, their brain can release endorphins and other neurotransmitters that contribute to pain relief and a sense of well-being. This response can lead to subjective improvements in pain intensity and functional abilities.

In the specific case of neck pain, clinical trials evaluating various treatments often include a placebo control group. Participants in the control group receive an inactive treatment, such as a sugar pill or a sham procedure, while another group receives the active treatment being tested. By comparing the outcomes of the active treatment group to those of the placebo group, researchers can assess the true effectiveness of the treatment beyond the placebo effect.

Interestingly, even when participants are fully aware that they are receiving a placebo, they may still experience some level of pain relief. This suggests that psychological factors, such as the patient's belief in the treatment and the therapeutic context, can contribute to the placebo effect.

It's important to note that while the placebo effect can produce real improvements in subjective experiences, it does not address the underlying cause of the condition. It may provide temporary relief or enhance the effectiveness of other treatments, but it does not result in long-term healing or resolution of the issue.

Healthcare professionals are aware of the placebo effect and strive to distinguish true treatment effects from placebo effects when evaluating the efficacy of interventions. They use rigorous scientific methods, such as randomized controlled trials, to ensure accurate assessments of treatments and to differentiate between actual therapeutic effects and placebo responses.

In summary, the placebo effect can have a noticeable impact on the perception of pain relief and treatment outcomes in neck pain. However, it is essential to differentiate between true treatment effects and the placebo response when evaluating the effectiveness of interventions. Healthcare professionals rely on scientific research and clinical evidence to guide the selection of appropriate treatments for neck pain.


In this Zheln Thread, we have seen a case study of how important health research evidence can be published and rest unused and not disseminated through the most popular media channels. Although a good systematic review has shown that the placebo effect plays a great role in how neck pain treatments are effective in the first place, popular media outlets, as of now, do not cover the role of placebo in neck pain whatsoever, leave alone the evidence from this systematic review.

Along the way, we have noticed important flaws in how popular media convey research. Particularly, we have seen how they can mislead the reader into trusting a research study whereas they only assessed the journal where the study had been published, not the study itself. In other instances, they have falsely claimed that the link leads to supporting evidence whereas, upon clicking, there is none.

Clearly, important health evidence needs to be brought to daylight. Moreover, popular outlets are no longer efficient in collecting, assessing, and conveying this evidence to the general public. The explosive rise of generative artificial intelligence does not currently lead in the right direction.

Here at Zheln, we are determined to fix that. Join us on our way to building the world’s first evidence outlet.

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