2004 Outstanding Paper Award: Nonoperative ScienceDiscographic, MRI and psychosocial determinants of low back pain disability and remission: a prospective study in subjects with benign persistent back pain
Introduction
Low back pain (LBP) associated with functional decline or disability is a common and costly medical and social problem [1], [2], [3], [4], [5]. Previous large and well-designed studies suggested that a history of LBP could be the most powerful predictor of future, serious LBP [6], [7]. Other risk factors suggested to correlate with the development of significant LBP illness have included structural factors, exposure to mechanical stressors, psychological factors and social circumstances [1], [2], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19]. The relative contribution of psychosocial versus structural factors has been the subject of controversy and debate.
Some investigators suggested that it is the morphologic status of the intervertebral disc complex, specifically the annulus or end plates, that primarily determines the presence and degree of low back problems [8], [15], [20], [21], [22]. Others suggested that disabling LBP illness is determined in large part by psychosocial or neurophysiologic factors (somatic distress, pain amplification, depression, secondary gain, etc.) [4], [6], [11], [12]. Which of these hypotheses could in fact be most valid has proven difficult to test using standard epidemiologic methods. Because the incidence of serious disabling LBP illness is low, resources have not allowed a sufficient number of subjects with defined degenerative changes (magnetic resonance imaging [MRI] or other imagining) and “at risk” psychosocial variables to be followed in a prospective fashion.
In previous studies risk factors were assessed in chronic LBP treatment groups and prospectively in occupational settings or in population cohorts. Few of these studies defined the spinal degeneration status with MRI, discography, or both findings. Small cohorts of asymptomatic subjects have been followed after magnetic resonance (MR) scanning or discography of the lumbar spine, but the subject numbers were small and these studies were inconclusive because of low statistical power [11], [13], [14], [23]. Because the incidence of serious or disabling LBP problems is relatively small in healthy individuals, prospective trials performed on an asymptomatic group are likely to lack the statistical power to detect significant trends without an extremely large sample size and extended follow-up.
However, by studying a medium-sized cohort of subjects (n=100) with baseline profiles suggested in previous literature to correlate with increased incidences of serious LBP illness, the predictive power of analysis is substantially increased. That is, a cohort of subjects, for instance, with a known propensity for degenerative disc disease, psychological distress or both would be expected to have a higher (and therefore measurable) incidence of future serious LBP illness. A prospective observational study of reasonable size could analyze the rates of serious adverse LBP outcomes.
As cited above, previous investigations indicated that persons with previous or current nondisabling LBP are at a greater risk of developing serious LBP problems and disability [6], [7], [9]. We selected such a group with a history of LBP as the primary group for this study to increase the statistical power of the sample. Then, systematically recruiting a cohort of subjects with chronic mild LBP, a propensity to degenerative disk disease (DDD), chronic pain and psychological distress at baseline would allow their relative predictive effects to be studied within a manageable cohort size. To our knowledge, a group with ongoing benign back pain but no serious LBP problems has never been studied for the above-mentioned factors in a prospective manner to determine the natural history or predictive factors determining eventual outcomes.
Therefore, to define the predictive factors for serious LBP problems we selected a cohort of subjects with ongoing mild LBP pain, without current or past LBP disability but a known propensity to DDD. This study examined such a cohort at baseline for radiographic, MRI and discographic evidence of structural changes, as well as demographic, occupational and psychometric features. We then followed this group over 5 years with interval assessments for LBP problems and reported on the subsequent values of baseline variables to predict future significant LBP variables.
Section snippets
Study design
This study was a prospective, longitudinal, observational study designed according to statistical power analysis (see “Power analysis”) to investigate the effect of spinal degenerative factors and nonspinal factors on the subsequent development of LBP episodes. All subjects recruited had known risk factors for degenerative lumbar disc disease and a history of mild, persistent but nondisabling LBP. Subject selection was biased (2:1) to subjects with a history of chronic nonlumbar pain, because
Baseline demographics and imaging studies
As previously discussed, the recruitment process was intended to produce a population with relatively high risk of future LBP illness on the basis of baseline disc degeneration, neurophysiologic factors or psychosocial factors. The demographic data of the study population are presented in Table 2. The resulting population of 100 subjects included 78 subjects with degenerated discs, types 3, 4 and 5 according to the Boos criteria (DDD); 64 subjects with chronic nonlumbar pain syndromes; and 45
Discussion
The cause of serious LBP illness in cases without clear and serious anatomic pathology is not known, yet two hypotheses have emerged to explain the development of LBP illness and associated disability. Some researchers have sought to define specific degenerative pathology in the spine that may, as an independent finding, cause the observed LBP illness [8], [11], [15], [18], [19], [20], [21], [25], [37], [38], [39]. In contrast, others have pointed to psychosocial issues as the main determinant
Conclusion
The development of serious LBP disability in a cohort of subjects with both structural and psychosocial risk factors was strongly predicted by baseline psychosocial variables. Structural variables on both MRI and discography testing at baseline had only weak association with back pain episodes and no association with disability or future medical care.
References (50)
- et al.
Discography: a review
Spine J
(2001) - et al.
Negative affect and the experience of chronic pain
J Psychosom Res
(1992) - et al.
Provocative discography in volunteer subjects with mild persistent low back pain
Spine J
(2002) The modified somatic perception questionnaire
J Psychosom Res
(1983)Psychological and functional profiles in select subjects with low back pain
Spine J
(2001)- et al.
A Fear-Avoidance Beliefs Questionnaire (FABQ) and the role of fear-avoidance beliefs in chronic low back pain and disability
Pain
(1993) - et al.
Demographic characteristics of persons with acute herniated lumbar intervertebral disc
J Chronic Dis
(1975) - et al.
An historical perspective on low back pain and disability
Acta Orthop Scand Suppl
(1989) - et al.
Chronic low back pain and fusion: a comparison of three surgical techniques: a prospective multicenter randomized study from the Swedish lumbar spine study group
Spine
(2002) - et al.
A systematic review of psychological factors as predictors of chronicity/disability in prospective cohorts of low back pain
Spine
(2002)
Spinal pain mechanisms
Spine
Personal risk factors for first-time low back pain
Spine
A prospective study of work perceptions and psychosocial factors affecting the report of back injury
Spine
High-intensity zone: a diagnostic sign of painful lumbar disc on magnetic resonance imaging
Br J Radiol
Isometric lifting strength as a predictor of industrial back pain reports
Spine
The role of spinal flexibility in back pain complaints within industry. A prospective study
Spine
Natural history of individuals with asymptomatic disc abnormalities in magnetic resonance imaging: predictors of low back pain-related medical consultation and work incapacity
Spine
Spine update: back injury and work loss: biomechanical and psychosocial influences
Spine
Risk factors for lumbar disc degeneration: a 5-year prospective MRI study in asymptomatic individuals
Spine
The value of magnetic resonance imaging of the lumbar spine to predict low-back pain in asymptomatic subjects: a seven-year follow-up study
J Bone Joint Surg Am
Predictive signs of discogenic lumbar pain on magnetic resonance imaging with discography correlation
Spine
The prediction of chronicity in patients with acute attack of low back pain in a general practice setting
Spine
Familial disability patterns in individuals with chronic work-related spine injury/illness
Spine
The prevalence and clinical features of internal disc disruption in patients with chronic LBP
Spine
MR imaging of the lumbar spine: prevalence of intervertebral disk extrusion and sequestration, nerve root compression, end plate abnormalities, and osteoarthritis of the facet joints in asymptomatic volunteers
Radiology
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Funding to complete this study was received from the AO Foundation and Department research funding at Stanford University. Nothing of value received from a commercial entity related to this research.