The association between subgroups of MRI findings identified with latent class analysis and low back pain in 40-year-old Danes

Societal beliefs about pain may be more balanced than previously thought. Results of the Guernsey pain survey

BACKGROUND

Musculoskeletal pain is multidimensional and associated with significant societal impact. Persistent or chronic pain is a public health priority. A step towards high-value care is a contemporary understanding of pain. While pain-related knowledge has been examined in specific conditions (e.g. neck pain) knowledge of the public's broader understanding regarding musculoskeletal pain per se, warrants investigation. This study examined the public's knowledge and beliefs regarding musculoskeletal pain and pain management.

METHODS

This observational cohort study was conducted in Guernsey (January 2019-February 2020). Participants (n = 1656; 76.0% female) completed an online questionnaire capturing: demographics, pain experience, work absenteeism, understanding of pain and pain management, multidimensional influences, physical activity, pain catastrophising and healthcare decision-making. Statements were deemed true/false/equivocal and mapped to biopsychosocial/biomedical/neutral perspectives based upon contemporary literature. Descriptive statistics were analysed for each statement. Participants' responses were examined for alignment to a contemporary viewpoint and themes within responses derived using a semi-quantitative approach modelled on direct content analysis. Comparisons between participants with/without pain were examined (χ2-squared/Wilcoxon Rank Sum test).

RESULTS

Within the cohort 83.6% reported currently experiencing pain. The overarching theme was perspectives that reflected both biomedical and contemporary, multidimensional understandings of pain. Sub-themes included uncertainty about pain persistence and evidence-based means to reduce recurrence, and reliance upon healthcare professionals for guiding decision-making. Compared to those with pain, those without had a greater belief that psychological interventions may help and lower pain catastrophising.

CONCLUSIONS

Participants' understanding of pain demonstrated both biomedical and multidimensional pain understanding consistent with elements of a contemporary understanding of pain.

Identifying chronic low back pain phenotypic domains and characteristics accounting for individual variation: a systematic review

ABSTRACT

Interpatient variability is frequently observed among individuals with chronic low back pain (cLBP). This review aimed at identifying phenotypic domains and characteristics that account for interpatient variability in cLBP. We searched MEDLINE ALL (through Ovid), Embase Classic and EMBASE (through Ovid), Scopus, and CINAHL Complete (through EBSCOhost) databases. Studies that aimed to identify or predict cLBP different phenotypes were included. We excluded studies that focused on specific treatments. The methodological quality was assessed using an adaptation of the Downs and Black tool. Forty-three studies were included. Although the patient and pain-related characteristics used to identify phenotypes varied considerably across studies, the following were among the most identified phenotypic domains and characteristics that account for interpatient variability in cLBP: pain-related characteristics (including location, severity, qualities, and duration) and pain impact (including disability, sleep, and fatigue), psychological domains (including anxiety and depression), behavioral domains (including coping, somatization, fear avoidance, and catastrophizing), social domains (including employment and social support), and sensory profiling (including pain sensitivity and sensitization). Despite these findings, our review showed that the evidence on pain phenotyping still requires further investigation. The assessment of the methodological quality revealed several limitations. We recommend adopting a standard methodology to enhance the generalizability of the results and the implementation of a comprehensive and feasible assessment framework to facilitate personalized treatments in clinical settings.

10-year Longitudinal MRI Study of Intervertebral Disk Degeneration in Patients With Lumbar Spinal Canal Stenosis After Posterior Lumbar Decompression Surgery

STUDY DESIGN

A prospective longitudinal magnetic resonance imaging (MRI) study.

OBJECTIVE

The objective of this study was to describe the progression of intervertebral disk (IVD) degeneration in patients who underwent posterior decompression surgery for lumbar spinal canal stenosis (LSS).

SUMMARY OF BACKGROUND DATA

IVD degeneration contributes to the pathogenesis of LSS; however, the long-term consequences of degenerative changes after decompression surgery remain unknown.

MATERIALS AND METHODS

Of 258 consecutive patients who underwent posterior lumbar decompression surgery for LSS, 62 who underwent MRI at their 10-year follow-up were included; 17 age-matched asymptomatic volunteers were analyzed as controls. Three MRI findings representing IVD degeneration were graded on their severity: decrease in signal intensity, posterior disk protrusion (PDP), and disk space narrowing (DSN). Clinical outcome was assessed using the low back pain (LBP) score from the Japanese Orthopaedic Association scoring system. We examined the association between the progression of degenerative changes on MRI and LBP/associated factors using logistic regression adjusting for age at baseline and sex.

RESULTS

The severity of IVD degeneration tended to be higher in patients with LSS than asymptomatic volunteers at both baseline and follow-up. IVD degeneration progressed in all patients during the 10-year follow-up period. Progression of decrease in signal intensity and PDP was observed at L1/2 in 73% and at L2/3 in 34%, respectively (the highest frequencies in the lumbar spine). Progression of DSN was highest at L4/5 in 42%. The rates of PDP and DSN progression during the 10-year follow-up period tended to be greater in patients with LSS than in asymptomatic volunteers. No significant difference in the proportion of LBP deterioration was evident for individuals with and without MRI findings of progression.

CONCLUSIONS

Our study reveals a natural history of the long-term postoperative course of IVD degeneration after posterior decompression surgery for LSS. Compared with healthy controls, patients with LSS seemed to be predisposed to IVD degeneration. Lumbar decompression surgery may promote the progression of DSN; however, progression of IVD degeneration after lumbar decompression surgery was not associated with worsening LBP scores.

Modic changes as seen on MRI are associated with nonspecific chronic lower back pain and disability

BACKGROUND

Estimating the contribution of endplate oedema known as Modic changes to lower back pain (LBP) has been the subject of multiple observational studies and reviews, some of which conclude that the evidence for an association of Modic change with LBP is uncertain while others demonstrate a clear link. The clinical trials demonstrating the benefit of basivertebral nerve ablation, a therapeutic intervention, in a tightly defined homogenous patient group with chronic LBP and Modic changes type 1 or type 2, provides further evidence for the contribution of Modic changes to LBP and shows that in these subjects, nerve ablation substantially reduces pain and disability. These interventional studies provide direct evidence that Modic changes can be associated with lower back pain and disability. This review set out to explore why the literature to date has been conflicting.

METHODS

A narrative, forensic, non-systematic literature review of selected articles to investigate why the published literature investigating the association between Modic imaging changes and chronic low back pain is inconsistent.

RESULTS

This review found that previous systematic reviews and meta-analyses included both heterogeneous study designs and diverse patient syndromes resulting in an inconsistent association between Modic changes and nonspecific chronic lower back pain. Re-analysis of literature data focussing on more homogenous patient populations provides clearer evidence that Modic changes are associated with nonspecific chronic lower back pain and that type 1 Modic changes are more painful than type 2.

CONCLUSIONS

Studies using tightly defined homogenous patient groups may provide the best test for association between MRI-findings and pain and disability. Clinical benefit of basivertebral nerve ablation observed in randomised controlled trials further supports the association between type 1 and type 2 Modic changes with pain and disability.

Chronic back pain sub-grouped via psychosocial, brain and physical factors using machine learning

Chronic back pain (CBP) is heterogenous and identifying sub-groups could improve clinical decision making. Machine learning can build upon prior sub-grouping approaches by using a data-driven approach to overcome clinician subjectivity, however, only binary classification of pain versus no-pain has been attempted to date. In our cross-sectional study, age- and sex-matched participants with CBP (n = 4156) and pain-free controls (n = 14,927) from the UkBioBank were included. We included variables of body mass index, depression, loneliness/social isolation, grip strength, brain grey matter volumes and functional connectivity. We used fuzzy c-means clustering to derive CBP sub-groups and Support Vector Machine (SVM), Naïve Bayes, k-Nearest Neighbour (kNN) and Random Forest classifiers to determine classification accuracy. We showed that two variables (loneliness/social isolation and depression) and five clusters were optimal for creating sub-groups of CBP individuals. Classification accuracy was greater than 95% for when CBP sub-groups were assessed only, while misclassification in CBP sub-groups increased to 35-53% across classifiers when pain-free controls were added. We showed that individuals with CBP could sub-grouped and accurately classified. Future research should optimise variables by including specific spinal, psychosocial and nervous system measures associated with CBP to create more robust sub-groups that are discernible from pain-free controls.

Intermittent pain in patients with chronic low back pain is associated with abnormalities in muscles and fascia

We investigated the relationship between paravertebral muscles and perimuscular connective tissues of the thoracolumbar fascia region and the four types of pain in patients suffering from chronic low back pain. A total of 17 patients with chronic low back pain participated in this study. Ultrasound imaging method was used to measure the thickness and echogenicity of the paravertebral muscles and perimuscular connective tissues. The measurement site considered in this study was located lateral to the midpoint between L2-3 and L4-5 spines. In addition, age, gender, BMI, numerical rating scale and the short-form McGill pain questionnaire 2 (includes questions with respect to continuous pain, intermittent pain, neuropathic pain and affective descriptors) were used for assessment. Statistical analysis was performed using correlation analysis and multiple regression analysis. A significant association was observed between paravertebral muscle echogenicity at L2-3 and the numerical rating scale (r = 0.499), between paravertebral muscle echogenicity at L4-5 with numerical rating scale (r = 0.538) and intermittent pain (r = 0.594), and between perimuscular connective tissue thickness at L2-3 and numerical rating scale (r = 0.762). We observed that the factor influencing perimuscular connective tissue thickness at L2-3 and L4-5 was intermittent pain (β = 0.513, β = 0.597, respectively). It was also observed that some of the imaging findings were associated with age and BMI. In conclusion, we observed that paravertebral muscle echogenicity and perimuscular connective tissue thickness in patients with chronic low back pain were associated with pain, especially intermittent pain.

The Association of MRI Findings and Long-Term Disability in Patients With Chronic Low Back Pain

STUDY DESIGN

Longitudinal cohort study with 13-year follow-up.

OBJECTIVE

To assess whether long-term disability is associated with baseline degenerative magnetic resonance imaging (MRI) findings in patients with low back pain (LBP).

METHODS

In 2004-2005, patients aged 18 to 60 years with chronic LBP were enrolled in a randomized controlled trial and lumbar MRI was performed. Patients completed the Roland-Morris Disability Questionnaire (RMDQ) and the LBP Rating Scale, at baseline and 13 years after the MRI. Multivariate regression analysis was performed with 13-year RMDQ as the dependent variable and baseline disc degeneration (DD, Pfirrmann grade), Modic changes (MC), facet joint degeneration (FJD, Fujiwara grade) smoking status, body mass index, and self-reported weekly physical activity at leisure as independent variables.

RESULTS

Of 204 patients with baseline MRI, 170 (83%) were available for follow-up. Of these, 88 had Pfirrmann grade >III (52%), 67 had MC (39%) and 139 had Fujiwara grade >2 (82%) on at least 1 lumbar level. Only MC (β = -0.15, P = .031) and weekly physical activity at leisure (β = -0.51, P < .001) were significantly, negatively, associated with 13-year RMDQ-score (R² = 0.31).

CONCLUSION

DD and FJD were not associated with long-term disability. Baseline MC and weekly physical activity at leisure were statistically significantly associated with less long-term disability.

The degenerative lumbar disc: not a disease, but still an important consideration for OMPT practice: a review of the history and science of discogenic instability

BACKGROUND

A recent AAOMPT position paper was published that opposed the use of the term 'degenerative disc disease' (DDD), in large part because it appears to be a common age-related finding. While common, there are significant physiologic and biomechanical changes that occur as a result of discogenic degeneration, which are relevant to consider during the practice of manual therapy.

METHODS

A narrative review provides an overview of these considerations, including a historical perspective of discogenic instability, the role of the disc as a pain generator, the basic science of a combined biomechanical and physiologic cycle of degeneration and subsequent discogenic instability, the influence of rotation on the degenerative segment, the implications of these factors for manual therapy practice, and a perspective on an evidence-based treatment approach to patients with concurrent low back pain and discogenic degeneration.

CONCLUSIONS

As we consider the role of imaging findings such as DDD, we pose the following question: Do our manual interventions reflect the scientifically proven biomechanical aspects of DDD, or have we chosen to ignore the helpful science as we discard the harmful diagnostic label?

Does Overall Cervical Spine Pathology Relate to the Clinical Heterogeneity of Chronic Whiplash?

BACKGROUND AND PURPOSE

There remains limited evidence for the clinical importance of most imaging findings in whiplash. However, it is possible the type and number of findings on Computed Tomography (CT) may contribute to prognostic recovery models. The purpose is to interpret cervical spine pathologies in the context of known factors influencing recovery.

MATERIALS AND METHODS

This is a secondary analysis from a database of 97 acutely injured participants enrolled in a prospective inception cohort study. Thirty-eight participants underwent standard of care cervical spine CT in the emergency medicine department. All 38 participants were assessed at <1-week, 2-weeks, and 3-months post-injury and classified using percentage scores on the Neck Disability Index (recovered/mild (NDI of 0-28%) or moderate/severe (NDI ≥ 30%)). Between-group comparison of categorical variables (gender (male/female), presence of at least one CT finding (yes/no), and presence of ≥3 pathologies on CT (yes/no)) was conducted using 2-tailed Fisher's exact test.

RESULTS

Participants from both groups demonstrated at least one observable pathology. The group with persistent moderate/severe symptoms presented with significantly more pathology at baseline than those who later reported recovery or milder symptoms at 3-months post injury (p = 0.02).

CONCLUSIONS

This preliminary study, which needs replication in a larger cohort, provides foundation that the number of degenerative pathologies seen on initial post MVC CT may be associated with the subsequent clinical course of whiplash.

Are Magnetic Resonance Imaging Technologies Crucial to Our Understanding of Spinal Conditions?

Persistent spinal (traumatic and nontraumatic) pain is common and contributes to high societal and personal costs globally. There is an acknowledged urgency for new and interdisciplinary approaches to the condition, and soft tissues, including skeletal muscles, the spinal cord, and the brain, are rightly receiving increased attention as important biological contributors. In reaction to the recent suspicion and questioned value of imaging-based findings, this paper serves to recognize the promise that the technological evolution of imaging techniques, and particularly magnetic resonance imaging, is allowing in characterizing previously less visible morphology. We emphasize the value of quantification and data analysis of several contributors in the biopsychosocial model for understanding spinal pain. Further, we highlight emerging evidence regarding the pathobiology of changes to muscle composition (eg, atrophy, fatty infiltration), as well as advancements in neuroimaging and musculoskeletal imaging techniques (eg, fat-water imaging, functional magnetic resonance imaging, diffusion imaging, magnetization transfer imaging) for these important soft tissues. These noninvasive and objective data sources may complement known prognostic factors of poor recovery, patient self-report, diagnostic tests, and the "-omics" fields. When combined, advanced "big-data" analyses may assist in identifying associations previously not considered. Our clinical commentary is supported by empirical findings that may orient future efforts toward collaborative conversation, hypothesis generation, interdisciplinary research, and translation across a number of health fields. Our emphasis is that magnetic resonance imaging technologies and research are crucial to the advancement of our understanding of the complexities of spinal conditions. J Orthop Sports Phys Ther 2019;49(5):320-329. Epub 26 Mar 2019. doi:10.2519/jospt.2019.8793.

Genome-wide meta-analysis identifies genetic locus on chromosome 9 associated with Modic changes

BACKGROUND

Low back pain (LBP) is a common disabling condition. Lumbar disc degeneration (LDD) may be a contributing factor for LBP. Modic change (MC), a distinct phenotype of LDD, is presented as a pathological bone marrow signal change adjacent to vertebral endplate on MRI. It is strongly associated with LBP and has heritability around 30%. Our objective was to identify genetic loci associated with MC using a genome-wide meta-analysis.

METHODS

Presence of MC was evaluated in lumbar MRI in the Northern Finland Birth Cohort 1966 (n=1182) and TwinsUK (n=647). Genome-wide association analyses were carried out using linear regression model. Inverse-variance weighting approach was used in the meta-analysis.

RESULTS

A locus associated with MC (p<5e-8) was found on chromosome 9 with the lead SNP rs1934268 in an intron of the PTPRD gene. It is located in the binding region of BCL11A, SPI1 and PBX3 transcription factors. The SNP was nominally associated with LBP in TwinsUK (p=0.001) but not associated in the UK Biobank (p=0.914). Suggestive signals (p<1e-5) were identified near XKR4, SCIN, MGMT, DLG2, ZNF184 and OPRK1.

CONCLUSION

PTPRD is a novel candidate gene for MC that may act via the development of cartilage or nervous system; further work is needed to define the mechanisms underlying the pathways leading to development of MC. This is the first genome-wide meta-analysis of MC, and the results pave the way for further studies on the genetic factors underlying the various features of spine degeneration and LBP.