Research Review By Dr. Ceara Higgins©

Audio:

Download MP3

Date Posted:

October 2020

Study Title:

The clinical utility of routine spinal radiographs by chiropractors: a rapid review of the literature

Authors:

Corso M, Cancelliere C, Mior S, et al.

Author's Affiliations:

Ontario Tech University and Centre for Disability Prevention and Rehabilitation, Oshawa, Canada; Canadian Memorial Chiropractic College, Toronto, Canada.

Publication Information:

Chiropractic & Manual Therapies 2020; 29: 33.

Background Information:

In 2010, 204 of every 1000 new patients presenting to a chiropractor in the United States received radiographs within 5 days of initial presentation (1), and the rate of spinal radiography by chiropractors and podiatrists increased by 14.4% between 2003 and 2015 (2). There are a lot of chiropractors taking a lot of spinal x-rays! But, should they be doing this?

Current guidelines suggest the use of radiographs in the presence of signs and symptoms of potentially serious underlying pathology (commonly referred to as ‘red flags’). However, certain factions of chiropractors endorse the use of routine or repeat radiographs to assess spinal structures and function (3). In fact, this practice forms the basis for approximately 23 chiropractic technique systems (ex. Gonstead, Chiropractic Biophysics, NUCCA and others), which would (hopefully?) suggest that routine and repeat radiographs are supported by scientific evidence. Proponents of these techniques have published their own guidelines to assist clinicians with the biomechanical assessment of spinal subluxation through radiography (4). These claims have not been evaluated for their clinical utility, nor the benefit a patient may glean from a given test or the resultant treatment (5).

The authors of this study conducted an independent, rapid review of the literature to investigate the clinical utility (including diagnostic utility and therapeutic utility) of routine and repeat radiographs (without red flags) for the structural and functional assessment of the spine by chiropractors. As well, they investigated whether functional or structural findings on repeat radiographs are valid markers of clinically meaningful change. This required them to first determine the validity and reliability of radiographs for functional and structural assessment of the spine.

Pertinent Results:

After screening 176 full text articles and critically appraising 23, 9 low risk of bias studies were ultimately included in the best evidence synthesis. This included 8 reliability studies (5 of which examined the intra- and inter-rater reliability of Chiropractic BioPhysics®️, one which examined the intra- and inter-rater reliability of flexion-extension radiographs when added to a standard cervical radiograph series, and one investigating the inter-rater reliability of vertebral rotation and tilt of lateral bending radiographs), and 2 phase two diagnostic (validity) studies (investigating whether patients with radiographic findings were more likely to have the target disorder than patients with other test outcomes). No relevant studies were found investigating the diagnostic or therapeutic utility of routine or repeat radiographs for structural or functional evaluation of the spine and no studies were found which investigated the use of repeat radiographs to monitor clinically meaningful changes in conditions or care for patients.

Four studies investigating measurements of the cervical spine and one investigating measurements of the lumbar spine using Chiropractic BioPhysics®️ found acceptable levels of reliability with the exception of the arcuate angle, which had a low to acceptable level of reliability in both the cervical and lumbar spine. Two studies found that ordering vertebral body rotation and tilting into five categories and measuring intersegmental motion of each vertebra in flexion and extension was also associated with poor reliability and significant measurement error.

No studies of acceptable quality were found that provided evidence of the diagnostic accuracy of Chiropractic BioPhysics measurements. As a result, it is unknown if they are evaluating clinically important outcomes for conditions in the cervical or lumbar spine.

One study was found which evaluated the diagnostic validity of cervical radiographic measurement in patients with and without cervical spine complaints and found no significant differences in head anterior weight bearing. However, participants with less than 20º of absolute rotation angle (a measurement of cervical lordosis) were greater than two times more likely to have cervical complaints. Another study looked at the benefits of adding cervical flexion-extension radiographs to a standard cervical series for the diagnosis of intersegmental clinical hypermobility. No additional diagnostic benefits were found.

No relevant studies were found that investigated the diagnostic or therapeutic utility of cervical, thoracic, or lumbar radiographs for functional and structural evaluation of the spine.

Implications:

The result of this review is in conflict with the International Chiropractic Association publication entitled ”Practicing Chiropractors’ Committee on Radiology Protocols (PCCRP) for Biomechanical Assessment of Spinal Subluxation in Chiropractic Clinical Practice”, which is frequently referenced by a subset of chiropractors to justify the use of routine or repeat radiographs. This conflict can be attributed to the differences in search strategy and article selection. The development of the PCCRP document did not include a risk of bias assessment, allowing for the inclusion of low-quality studies which are likely to have biased the recommendations.

In 2017, the American Chiropractic Association adapted the Choosing Wisely®️ recommendations on lumbar spine radiography (15), which recommend the avoidance of routine spinal imaging for individuals with acute low back pain of less than 6 weeks duration in the absence of clear clinical indicators. The American Chiropractic Association further recommended that repeat imaging should not be used to monitor patients’ progress (14).

Radiographs utilize ionizing radiation. A known risk of exposure to ionizing radiation is (still) an increased frequency of cancer. Currently, the most widely used theory on radiation accumulation is based on the linear no-threshold (LNT) model, which states: no dose of radiation exists without risk and the risk increases proportionally with dose (16). Therefore, although radiographs provide a very low dose, they must be considered as part of the patient’s lifetime exposure. As a result, the International Commission on Radiological Protection (ICRP) and the Canadian Nuclear Safety Commission (CNSC) recommend following the “as low as reasonably achievable” (ALARA) principle. This suggests that we should not be using routine or repeat radiographs to assess function or structure of the spine.

Clinical Application & Conclusions:

No evidence was found to indicate that cervical, thoracic, or lumbar radiographs (in the absence of red flags) taken for the evaluation of the function or structure of the spine are of benefit to patients. In addition, ionizing radiation has inherent risks. Therefore, routine or repeat radiographs of the spine for the purpose of evaluating structure or function are not recommended.

EDITOR’S NOTE/OPINION: Let me clarify that I believe that many of the chiropractic techniques that rely heavily on routine radiography can be of benefit to patients. However, I also strongly believe that these clinical benefits could largely be obtained without the radiographs – that is, their treatment techniques, adjustments etc. are likely beneficial, but their imaging measurements or techniques are invalid, unnecessary, or both. If this were not the case, the literature would (by this point) be flush with comparative studies showing the superiority of routine imaging for enhancing clinical results versus those techniques or clinical approaches that do not use imaging in this manner. At this point, to my knowledge, no such studies exist.

Study Methods:

At the request of the College of Chiropractors of British Columbia (CCBC, in Canada), the authors conducted a rapid review of the literature using methodology recommended by the World Health Organization. The review was reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) and PRISMA Harms checklist (8).

Clinical utility (the benefit that a person has from an intervention or test) includes both diagnostic utility (the degree to which the use of a test is associated with changing health outcomes) and therapeutic utility (the degree to which a test contributes to improving health outcomes through the selection of appropriate treatment) (5-7). To determine the clinical utility of a test requires a well-designed randomized clinical trial showing that patients benefit from the test. As well, the validity, diagnostic accuracy and reliability of the test must be shown (9). Finally, the test must be shown to have clinical utility, in that it impacts health outcomes.

Inclusion criteria for this review were as follows:
  • Studies of patients presenting to chiropractors who received spinal radiographs of the cervical, thoracic, or lumbar areas, in the absence of red flags.
  • Studies with comparisons to individuals who did not receive spinal radiographs or were assessed using other methods of spinal examination
  • Studies utilizing structural or functional outcomes, including assessing for asymmetry in vertebral alignment as measured by line drawings, spinal curvatures, and the presence or correction of vertebral dysfunction as identified by measurement or positional listings
  • Studies with patient centred outcomes, including pain, function, self-reported recovery, health related quality of life, or well-being
  • RCTs, cohort studies, and diagnostic or reliability studies
The authors excluded guidelines, letters, editorials, commentaries, unpublished manuscripts, dissertations, government reports, books and book chapters, conference proceedings, meeting abstracts, lectures and addresses, consensus development statements, guideline statements, cadaveric, laboratory, or animal studies, qualitative studies, systematic reviews, and meta-analyses.

A two-phase screening process was used. Titles and abstracts were reviewed first and then the full texts of all possibly relevant articles were reviewed to determine eligibility. All screening was conducted by a trained investigator. Risk of bias was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) criteria for RCTs, cohort studies and case-control studies, a checklist created by Hoy et al. for cross-sectional studies, the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) for diagnostic studies and the Quality Appraisal tool for studies of diagnostic Reliability (QAREL) for reliability studies (11-13).

Data extraction was performed by the lead author and validated by one of four reviewers to ensure accuracy. Data extracted from diagnostic studies included the study design, sample population, case definition, index test, reference standard, and results of the study. Data extracted from reliability studies included study design, sample size, sample description, measurement method, and results of the study.

Study Strengths / Weaknesses:

Strengths:
  • The search strategy was developed in consultation with a health sciences librarian and reviewed by a second librarian to ensure accuracy.
  • The quality of article screening was validated by randomly selecting 10% of all eligible articles and having them screened independently by a second experienced investigator. A 95% agreement between assessors was required before moving on to full screening.
  • Internal validity of relevant articles was appraised using the Scottish Intercollegiate Guidelines Network (SIGN) criteria for RCTs , cohort studies, and case-control studies (10), a checklist by Hoy, et al. for cross-sectional studies (11), the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) for diagnostic studies (12), and the Quality Appraisal toll for studies of diagnostic Reliability (QAREL) for reliability studies (13).
  • Quality control for the assessment of risk of bias was performed. A summary of the critically appraised papers was presented to four experienced methodologists who validated the appraisals.
Weaknesses:
  • This study used a focused search of the literature which may have led to studies being missed.
  • Screening, critical appraisal, and data extraction were all performed by one investigator.

Additional References:

  1. Bussières AE, Sales AE, Ramsay T, et al. Practice patterns in spine radiograph utilization among doctors of chiropractic enrolled in a provider network offering complementary care in the United States. J Manip Physiol Ther 2013; 36: 127-142.
  2. Mizrahi D, Parker L, Zoga A, et al. National trends in the utilization of skeletal radiology from 2003 to 2015. J Am Coll Radiol 2018; 15: 1408-1414.
  3. Jenkins HJ, Downie AS, Moore CS, et al. Current evidence for spinal X-ray use in the chiropractic profession: a narrative review. Chiropr Man Ther 2018; 26: 1-11.
  4. Harrison D, Harrison D, Kent C, et al. Practicing Chiropractors’ Committee on Radiology Protocols (PCCRP) for Biomechanical Assessment of Spinal Subluxation in Chiropractic Clinical Practice; 2009: p. 1-387.
  5. Lesko LJ, Zineh I, Huang SM. Editorial: what is clinical utility and why should we care? Clin Pharmacol Ther 2010; 88: 729-733.
  6. Bossuyt PMM, Reitsma JB, Linnet K, et al. Beyond diagnostic accuracy: the clinical utility of diagnostic tests. Clin Chem 2012; 58: 1636-1643.
  7. Nelson-Gray RO. Treatment utility of psychological assessment. Psychol Assess 2003; 15: 521-531.
  8. Moher D, Liberati A,Tetzlaff J, et al. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med 2009; 6: e1000097.
  9. Fletcher RH, Fletcher SW, Wagner EH. Clinical epidemiology, the essentials. Third edit. Baltimore, Maryland: Williams & Wilkins; 1996.
  10. Harbour R, Miller K. A new system for grading recommendations in evidence based guidelines. Br Med J (Clinical Res Ed) 2001; 323:334-336.
  11. Hoy D, Brooks P, Woolf A, et al. Assessing risk of bias in prevalence studies: modification of an existing tool and evidence of interrupter agreement. J Clin Epidemiol 2012; 65: 934-939.
  12. Whiting P, Weswood M, Rutjes A, et al. Evaluation of QUADAS, a tool for the quality assessment of diagnostic accuracy studies. BMC Med Res Methodol 2006; 6: 9.
  13. Lucas N, Macaskill P, Irwin L, et al. The reliability of a quality appraisal tool for studies of diagnostic reliability (QAREL). BMC Med Res Methodol 2013; 9: 111.
  14. Imaging Tests for Low Back Pain: When you need them - and when you don’t. 2017. https://choosingwiselycanada.org/wp-content/uploads/2017/05/Low-Back-Pain-EN.pdf.
  15. American Chiropractic Association Five Things Physicians and Patients Should Question. Choosing Wisely. 2019. https://www.choosingwisely.org/societies/american-chiropractic-association/.Assessed 16 Mar 2020.
  16. Lin EC. Radiation risk from medical imaging. Mayo Clin Proc 2010; 85: 1142-1146.