Compelling evidence has long shown that diagnostic imaging for low back pain does not improve care in the absence of suspicion of serious pathology. However, the effect of imaging use on clinical outcomes has not been investigated in patients presenting to chiropractors. The aim of this study was to determine if diagnostic imaging affects clinical outcomes in patients with low back pain presenting for chiropractic care.

A matched observational study using prospective longitudinal observational data with a one-year follow-up was performed in primary care chiropractic clinics in Denmark. Data were collected from November 2016 to December 2019. Participants included low back pain patients presenting for chiropractic care, who were either referred or not referred for diagnostic imaging at their initial visit. Patients were excluded if they were younger than 18 years, had a diagnosis of underlying pathology, or had previously had imaging relevant to their current clinical presentation. Coarsened exact matching was used to match participants referred for diagnostic imaging with participants not referred for diagnostic imaging on baseline variables including participant demographics, pain characteristics, and clinical history. Mixed linear and logistic regression models were used to assess the effect of imaging on back pain intensity and disability at two weeks, three months, and one year, and on global perceived effect and satisfaction with care at two weeks.

A total of 2162 patients were included, and 24.1% of them were referred for imaging. Near perfect balance between matched groups was achieved for baseline variables except for age and leg pain. Participants referred for imaging had slightly higher back pain intensity at two weeks (0.4, 95%CI: 0.1, 0.8) and one year (0.4, 95%CI: 0.0, 0.7), and disability at two weeks (5.7, 95%CI: 1.4, 10.0), but these differences are unlikely to be clinically meaningful. No difference between groups was found for the other outcome measures. Similar results were found when a sensitivity analysis, adjusted for age and leg pain intensity, was performed.

The authors concluded that diagnostic imaging did not result in better clinical outcomes in patients with low back pain presenting for chiropractic care. These results support that current guideline recommendations against routine imaging apply equally to chiropractic practice.

This study confirms what most experts suspected all along and what many chiropractors vehemently denied for years. One could still argue that the outcomes do not differ much and therefore imaging does not cause any harm. This argument would, however, be wrong. The harm it causes does not affect the immediate clinical outcomes.  Needless imaging is costly and increases the cancer risk.

26 Responses to Does diagnostic imaging affect the clinical outcome in patients with low back pain presenting for chiropractic care?

  • I think this is outstanding, 20 years ago 75% (or so) of patients were imaged/x-ray by chiropractors. Maybe Dr Ernst and the almighty internet has changed their ways. Unnecessary radiation has turned the patients to saying no. Actual subluxations are shown on x-rays, imaginary ones are not. Bravo!

  • This manuscript, I strongly suggest is significantly flawed. I look forward to the ongoing debate. Here is my initial evidence to support my opinion.

    • no surprise there then

    • I had a look at the paper . I want to know what these authors are smoking. It must be fairy dust of some kind?
      This parody is nothing less than laughable. The authors even claim without any attempt at providing evidence:

      “ A radiograph may in fact stimulate our protective sys- tems, which is a beneficial health effect.”

      Did you honestly read the paper before putting the link in a comment, mr. Epstein?

      • you are putting the bar far too high for him

      • A radiograph may in fact stimulate our protective sys- tems, which is a beneficial health effect

        The radiation dose from a radiograph is far too low to have any measurable non-stochastic effects (i.e. dose-related effects). The concerns are about stochastic effects (all-or-nothing events where the probability is related to the radiation dose; basically cancer).

        Higher doses, as used in radiotherapy, have clear effects on many body systems. One thing they do is to kill inflammatory cells, and radiotherapy is a very effective treatment for inflammatory back pain, for instance in ankylosing spondylitis. However, it is not used any more because of the cancer risk. Possibly the authors had half-remembered something about this and completely misunderstood it.

        • That’s very interesting.

          My late father was wounded in the Normandy Landings in 1944, serving in the Royal Engineers. He had two or three years of various treatments following this, and I have a handwritten list that he wrote, setting these down in order. In 1947 he had something called “Deep X-Ray treatment”. I did previously find a 1947 paper, I think a BMJ article, which I can’t now find, talking about this treatment for tissue healing. I found this reference this evening:

          He also lists some three months spent in a “plaster jacket” (exactly as depicted in the excellent docu-drama about Dr. Ludwig Guttman, “The Best Of Men”). Life in a plaster jacket must have been horrible!

          My father died age 60 in 1980 of acute myeloid leukaemia, and I mused (in my ignorant and unqualified way) about whether Deep X-Ray treatment 33 years previously, might have had anything to do with that.

          • Deep x-ray treatment was the name given to a type of radiotherapy, more correctly called orthovoltage radiotherapy, and some older radiotherapists still use the abbreviation DXT to refer to radiotherapy in general.

            X-rays for diagnostic imaging are generated by using an electric potential of tens of thousands of volts to accelerate electrons in a vacuum tube towards an anode target usually made from tungsten. When the electrons strike the target they produce a shower of photons at a spectrum of energies up to a maximum (in electron volts) equal to the voltage applied across the tube. This beam is then passed through a “hardening filter”, usually of copper or aluminium, to remove the lower energy photons, and a “flattening filter” of variable thickness to even out the intensity of the beam. It is then collimated and the result is a beam of x-rays that are clinically useful.

            Although such x-rays are used to see deep inside the body, in fact nearly all of them are stopped by the skin and only a small proportion penetrate all the way through. Higher energies penetrate better, but the energies used are chosen to give the maximum contrast between bones and soft-tissue as in the kilovoltage range absorption is by the photoelectric effect and proportional to the cube of the atomic number of the nucleus they are interacting with.

            Similar x-rays but of higher intensity are used in radiotherapy for treating skin tumours such as basal cell carcinoma; this is known as superficial x-ray treatment.

            If the voltage is increased to several hundred thousand volts, the x-ray beam is more penetrating and less of the energy is deposited in and just below the skin. It can be used for treating deeper tumours and the preferential bone absorption is still useful for bony secondaries that aren’t situated too deeply within the body, such as ribs, where the relatively poor penetration spares the underlying lungs.

            Early radiotherapists used ingenous beam arrangements to try to even out the dose in order to treat deeper stuctures without too much skin damage, but such treatment still left quite marked scarring behind with a very characteristic appearance.

            Unfortunately it isn’t practical to increase the voltage beyond about 300 KV as air stops being an insulator above that. The warnings at electricity sub-stations which say “danger of death” are very true, as you don’t have to touch the wires to receive a fatal shock. For this reason gamma rays from radioactive isotopes were often used, with cobalt-60 and caesium-137 being particularly useful sources due to the energies emitted and a high specific activity, meaning that a relatively small source could approximate to a point. Cobalt units were used for most routine radiotherapy treatments when I was starting out in radiotherapy.

            Now, however, most x-rays used for treatment are generated by linear accelerators, which can produce a beam in the range 6 – 20 million electron volts that have all the penetration required. The improvement in computing power over the last few years means that complex 3-D treatment plans can be calculated and delivered, allowing the radiation dose to be “painted” onto the tumour sites, avoiding critical normal tissues using what is called IMRT (intensity-modulated radiotherapy).

            Radiotherapy is also effective for a wide range of inflammatory conditions, including ankylosing spondylitis, but it is very rarely used these days for benign disease.

          • Thank you for that very interesting explanation, Dr. M-K!

          • David,

            You are very welcome. I thought you would find it interesting and it is probably not something that you could easily look up.

          • I had never really thought about x-ray wavelengths as having anti-inflammatory effects.

            But maybe I should have, since I have myself had UVB and NarrowBand UVB phototherapy for eczema, and found it very effective.

            It is fairly ‘classic’ (in the UK) for a child with atopic eczema to experience a marked improvement when on a seaside holiday with the family. The improvement is understood to be multifactorial, but with increased UV exposure being a major factor, as most of the child’s skin is exposed, and UV radiation reduces the numbers of Langerhans cells and other immunocompetent cells in the epidermis, driving them further down.

            Overdo it, of course, and you increase the chance of melanoma…..

      • @Björn Geir
        The bone quackers in that article probably refer to the following:

        It’s a common modus operandi for SCAM practitioners: when stumbling upon something completely unproven so far, immediately run with it and use it to ‘support’ your practice, without any proper evidence.

      • In the past I have tried to have discussions with these authors regarding some issues in their papers. May as well try to teach a pig to sing.

      • Dear Bjorn, I have read all the papers a number of times plus many more. Putting aside your concern about the evidence supporting the principle that harm from low dose radiation is negligible. The debate is really about the use of X-ray imaging for the non-surgical management of spinal disorders. the evidence is robust and leans towards superior outcomes compared to standard physiotherapy and just spinal manipulative therapy. The three peer-reviewed papers presented will detail the train of critical thinking(not dreaming) on this ongoing debate.

        • Not standard physical therapy in the papers I have read. Usually some hodgepodge PT approach.

          Very few (maybe around 1%) of chiropractors only do SMT. So basically no clinical application to the profession.

          No studies comparing CBP with or without x rays. Granted hard to do since they pretty much need the x ray.

          No studies comparing CBP to typical or standard chiropractic approaches.

          No studies comparing CBP to an evidence based manual therapy approach.

          CBP authors have shown:

          1. They can reliably reposition subjects for x rays.

          2. They can change spinal configuration over the short term (usually one year with less regression compared to some other intervention) .

          I have explained to them several times what they need to research in order to be taken seriously. I am still waiting for that research to be published.

          Also, look up the references they use in their papers. Sometimes it actually contradicts their own use in the paper.

          The whole hormesis thing, to my knowledge it’s never been shown with x rays as chiropractors tend to use them.

          Do I think improving spinal configuration can help some conditions? Yes. Is there good research with CBP or similar approaches to demonstrate it? No. (Hint, focus on the discs).

      • All I hear are crickets. I read no response.

  • “A total of 2162 patients were included, and 24.1% of them were referred for imaging.”

    compared to?

    “Although clinicians vary substantially in how frequently they obtain low back pain imaging (7, 52), some continue to order imaging routinely or without a clear clinical indication. In a survey (3), about 40% of family practice and 13% of internal medicine physicians reported ordering routine diagnostic imaging for acute low back pain. Another survey (4) found that in the absence of any worrisome features, 22% of physicians would obtain lumbar spine radiography for acute low back pain without sciatica and 62% would do so for low back pain with sciatica. Data on actual imaging practices support these survey results. Among 35 000 Medicare beneficiaries with acute low back pain and no diagnostic code indicating a serious underlying condition, nearly 30% had lumbar radiography within 28 days (53), even though the ACP/APS guideline (5) suggests a trial of management without imaging in adults with no risk factors other than older age. An Australian study (54) showed a slight increase in imaging rates in general practice for patients with new low back pain, despite the publication of guidelines that recommend against routine imaging.”

    Looks like we all need to do better.

    BTW: in the Jenkins, et al paper, it should be noted that for those with pain greater than 3 months, 30.4% were ordered imaging vs 9.7%. This is generally not considered “unnecessary”.

    Also, 4.6% sent for imaging had suspected pathology vs 0.4%, again not necessarily considered “unnecessary”.

    Also of note is that the exclusion criteria was for “…ongoing course of treatment or long-term management.’ Yet this leaves the question of those who have tried conservative therapies in the past but were unresponsive. Again, this is not necessarily considered “unnecessary” for imaging.

    • Looks like we all need to do better.

      Very true.

      In the UK a doctor is required to have completed basic training covering the harmful aspects of radiation exposure, how it is monitored, radiation protection in general and the Law as it governs these issues before they are allowed to sign a request for a diagnostic x-ray. I don’t know what the system is elsewhere.

      • In the Co-operative Shoe Shop where my mum used to take me for school shoes etc in the early 1960s there was a foot x-ray machine. It was not in use by then, but had not been removed. They were a sales gimmick from an earlier period, intended to demonstrate the fit of the foot inside the shoe, on a CRT screen. Sales assistants using them regularly must have had considerable exposure. I reflect on how diligently my dentist dodges round the corner out of sight before pressing the button to take an x-ray, which with today’s technology has an extremely short exposure time.

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