Diagnosing Low Back Pain of Disc, Sacroiliac Joint or Facet Joint Origin +MP3
Research Review By Dr. Joshua Plener©
Audio:
Date Posted:
May 2023
Study Title:
Low back pain of disc, sacroiliac joint, or facet joint origin: a diagnostic accuracy systematic review
Authors:
Han C, Hancock M, Sharma S, et al.
Author's Affiliations:
The University of Sydney, Sydney Musculoskeletal Health; Faculty of Medicine, health and Human Sciences, Macquarie University, Australia; Department of Exercise Physiology, School of Health Sciences, Faculty of Medicine and Health, University of New South Whales, Australia
Publication Information:
eClinicalMedicine 2023; 59:101960
Background Information:
Most clinical practice guidelines recommend general treatment approaches for low back pain, including exercise, medication or manual therapy (1). When studied, these interventions typically demonstrate small effect sizes and there is little to no information on how to individualize these treatments for patients (2).
The diagnosis of low back pain, particularly when attempting to identify a specific pain generating tissue, pathology or anatomical structure, remains a controversial discussion. The dominant view is that for 90% of patients with low back pain, their pain cannot be attributed to a specific pathology or structure and thus should be classified as non-specific low back pain. However, some believe that sub classification of non-specific low back pain is possible via the clinical presentation, clinical assessment and diagnostic imaging in order to identify a nociceptive source (3).
Potential sources of low back pain include the disc, facet joint, and sacroiliac joint. Clinically, it remains a challenge to identify the nociceptive source of low back pain within primary care due to the lack of availability of validated tests and the invasive nature of most reference standards such as disc provocation procedures or diagnostic blocks. However, there remains an interest to identify simpler diagnostic tests that could be used in order to identify the nociceptive source of low back pain. A previous review was conducted in 2007 which identified a relatively low number of studies that had investigated the diagnostic accuracy of tests. The review found that some tests such as MRI evidence of a high intensity zone and disc degeneration, and the centralization phenomenon could be informative to identify the disc as the pain generating source (4). Furthermore, a combination of sacroiliac joint provocation tests were found to modestly increase the likelihood of the sacroiliac joint causing the pain.
Many studies have been conducted since that previous review and as a result, the aim of this paper was to update the review to understand the current state of the literature regarding the accuracy of diagnostic tests available in primary care to identify the disc, sacroiliac joint, and facet joint as the source of low back pain.
The diagnosis of low back pain, particularly when attempting to identify a specific pain generating tissue, pathology or anatomical structure, remains a controversial discussion. The dominant view is that for 90% of patients with low back pain, their pain cannot be attributed to a specific pathology or structure and thus should be classified as non-specific low back pain. However, some believe that sub classification of non-specific low back pain is possible via the clinical presentation, clinical assessment and diagnostic imaging in order to identify a nociceptive source (3).
Potential sources of low back pain include the disc, facet joint, and sacroiliac joint. Clinically, it remains a challenge to identify the nociceptive source of low back pain within primary care due to the lack of availability of validated tests and the invasive nature of most reference standards such as disc provocation procedures or diagnostic blocks. However, there remains an interest to identify simpler diagnostic tests that could be used in order to identify the nociceptive source of low back pain. A previous review was conducted in 2007 which identified a relatively low number of studies that had investigated the diagnostic accuracy of tests. The review found that some tests such as MRI evidence of a high intensity zone and disc degeneration, and the centralization phenomenon could be informative to identify the disc as the pain generating source (4). Furthermore, a combination of sacroiliac joint provocation tests were found to modestly increase the likelihood of the sacroiliac joint causing the pain.
Many studies have been conducted since that previous review and as a result, the aim of this paper was to update the review to understand the current state of the literature regarding the accuracy of diagnostic tests available in primary care to identify the disc, sacroiliac joint, and facet joint as the source of low back pain.
Pertinent Results:
The search identified 3562 citations of which 21 new studies and 41 previous studies from the original review were included in the analysis. Of the 62 included studies, 35 investigated the disc, 14 investigated the facet joint and 11 investigated the sacroiliac joint. Sample sizes ranged from 15 to 736 participants and the estimated prevalence of pain originating from the discs, facet joint, and the sacroiliac joint within the studies were 46%, 42% and 53% respectively.
Discogenic Pain:
Index tests that were found to have an informative positive likelihood ratio for discogenic pain were:
- Studies using the Pfirrmann scale to grade the level of disc degeneration when the rating was greater than 3 or 4
- MRI evidence of a high intensity zone
- MRI evidence of an annular fissure
- MRI evidence of Type 1 Modic changes
- MRI evidence of Type 2 Modic changes
- A positive result when assessing for the centralization phenomenon, which is repeated end-range movement that results in distal pain originating from the spine progressively moving towards a central location
The index test that was found to have an informative negative likelihood ratio for discogenic pain was:
- The lack of MRI evidence of an annular fissure
Sacroiliac Joint:
Index tests that were found to have an informative positive likelihood ratio for sacroiliac joint pain were:
- Radionuclide imaging such as a bone scan
- Distraction test (supine patient, hand contacts on ASIS bilaterally, gentle repetitive force applied dorsolaterally – looking for reproduction of patient’s pain)
- Absence of midline low back pain
- Combination of 3 or more positive sacroiliac joint provocation tests
Index tests that were found to have an informative negative likelihood ratio for sacroiliac joint pain were:
- The presence of midline low back pain
- Combination of 3 or more sacroiliac joint provocation tests being negative
Facet Joint:
The index test that was found to have an informative positive likelihood ratio for facet joint pain was:
- Uptake of facet joint on single-photon emission computed tomography
The index test that was found to have an informative negative likelihood ratio for facet joint pain was:
- The lack of uptake of the facet joint on single-photon emission computed tomography
The diagnostic accuracy of Revel’s criteria to identify the facet joint as the source of pain was assessed in multiple studies. The criteria included 5 or more of the 7 clinical characteristics, consisting of: age 65 or greater, pain relieved by recumbency, pain not exacerbated by coughing, pain not exacerbated by extension/rotation, pain not exacerbated by forward flexion, pain not exacerbated by hyperextension, and pain not worse with rising. The studies assessing the Revel’s criteria provided mixed results on its positive and negative likelihood ratio.
Clinical Application & Conclusions:
Sixty studies investigated the diagnostic accuracy of index tests to identify the source of low back pain. Most studies in the review assessed the intervertebral disc, with a fewer number of studies looking at the facet joint and the sacroiliac joint. The results demonstrated that the presence of disc degeneration, high intensity zone, Modic type 1 changes, and Modic type 2 changes increased the likelihood of the disc being the nociceptive source of low back pain. In addition, the presence of facet joint uptake on single-photon emission computed tomography (SPECT) increased the likelihood of the facet joint being the nociceptive source. The only physical examination tests that provided helpful information for the disc and sacroiliac joint were positive centralization phenomenon (for discogenic pain), the absence of midline low back pain and a combination of sacroiliac joint pain provocation tests (for sacroiliac joint pain).
The results of this review demonstrate the possibility of identifying a pathoanatomical diagnosis for low back pain, albeit in a limited manner for facet joint pain (not many clinicians have access to SPECT imaging!). This paper informs us about the state of the literature and could result in more targeted and specific treatment approaches. However, this is still in the beginning stages and there is a need for more diagnostic research to evaluate our ability to identify a specific source of low back pain in our patients. As well, further research could expand to assess other structures such as muscles, fascia, ligaments and the vertebral body.
Although these results are intriguing, it is important to consider when a non-pathoanatomical diagnosis may be needed, as not all patients would benefit from a tissue specific diagnosis. For example, there is a lot of research demonstrating the negative impact certain diagnoses can have, leading to unnecessary imaging, over diagnosis and over treatment. Future research should aim to determine who may benefit more from a pathoanatomical diagnosis and if this can help predict prognosis or response to treatment. A pathoanatomical diagnosis may be more likely to benefit patients with persistent low back pain whereby a specific diagnosis may help select more targeted treatment. Understanding the impact of these diagnoses on outcomes and patient care should be a top priority.
The results of this review demonstrate the possibility of identifying a pathoanatomical diagnosis for low back pain, albeit in a limited manner for facet joint pain (not many clinicians have access to SPECT imaging!). This paper informs us about the state of the literature and could result in more targeted and specific treatment approaches. However, this is still in the beginning stages and there is a need for more diagnostic research to evaluate our ability to identify a specific source of low back pain in our patients. As well, further research could expand to assess other structures such as muscles, fascia, ligaments and the vertebral body.
Although these results are intriguing, it is important to consider when a non-pathoanatomical diagnosis may be needed, as not all patients would benefit from a tissue specific diagnosis. For example, there is a lot of research demonstrating the negative impact certain diagnoses can have, leading to unnecessary imaging, over diagnosis and over treatment. Future research should aim to determine who may benefit more from a pathoanatomical diagnosis and if this can help predict prognosis or response to treatment. A pathoanatomical diagnosis may be more likely to benefit patients with persistent low back pain whereby a specific diagnosis may help select more targeted treatment. Understanding the impact of these diagnoses on outcomes and patient care should be a top priority.
Study Methods:
MELDLINE, CINAHL and EMBASE were searched between March 2006 and January 25, 2023.
The eligibility criteria were as follows:
- Included participants had low back pain without serious pathology such as cancer, infection or fracture.
- Use of a reference standard test advocated by the International Association for the Study of Pain which are discography for discogenic pain, intra articular local anesthetic blocks for sacroiliac joint pain, and either intra-articular blocks or medial branch blocks for facet joint pain.
- Assessed at least one index test available to primary care clinicians.
- Presented a 2 x 2 table to understand the psychometric properties of the index test.
Two review authors independently screened abstracts and full texts and two authors used the Quality Assessment of Diagnostic Accuracy Studies Scale (QUADAS-2) to rate risk of bias independently. Following data extraction, data was pooled using a random effects model when possible.
The sensitivity, specificity and likelihood ratios were determined for the index tests. Likelihood ratios were considered informative if the positive likelihood ratio was 2 or greater and the negative likelihood ratio was 0.5 or less.
The sensitivity, specificity and likelihood ratios were determined for the index tests. Likelihood ratios were considered informative if the positive likelihood ratio was 2 or greater and the negative likelihood ratio was 0.5 or less.
Study Strengths / Weaknesses:
Strengths:
- The search strategy was comprehensive and followed a strict pre-specified protocol.
- There was a large number of studies which allowed for greater analysis of results.
- This is a very timely review which is clinically relevant.
Weaknesses:
- The prevalence of these conditions may have been inflated in the studies as they included patients referred to a tertiary setting rather than in primary care where these tests are more commonly used.
- Risk of bias was generally rated as high for the domain “reference standard” as most studies used a less strict criteria. This could have impacted the findings of the studies.
Additional References:
- Oliveira CB, Maher CG, Pinto RZ, et al. Clinical practice guidelines for the management of non-specific low back pain in primary care: an updated overview. Eur Spine J 2018; 27(11): 2791–2803.
- Koes BW, van Tulder M, Lin CW, et al. An updated overview of clinical guidelines for the management of non-specific low back pain. Eur Spine J 2010; 19(12): 2075-2094.
- Knezevic NN, Candido KD, Vlaeyen JWS, et al. Low back pain. Lancet 2021; 398(10294): 78–92.
- Hancock MJ, Maher CG, Latimer J, et al. Systematic review of tests to identify the disc, SIJ or facet joint as the source of low back pain. Eur Spine J 2007; 16(10): 1539–1550.
