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

Spinal degeneration and lumbar multifidus muscle quality may independently affect clinical outcomes in patients conservatively managed for low back or leg pain

Few non-surgical, longitudinal studies have evaluated the relations between spinal degeneration, lumbar multifidus muscle (LMM) quality, and clinical outcomes. None have assessed the potential mediating role of the LMM between degenerative pathology and 12-month clinical outcomes. This prospective cohort study used baseline and 12-month follow-up data from 569 patients conservatively managed for low back or back-related leg pain to estimate the effects of aggregate degenerative lumbar MRI findings and LMM quality on 12-month low back and leg pain intensity (0-10) and disability (0-23) outcomes, and explored the mediating role of LMM quality between degenerative findings and 12-month clinical outcomes. Adjusted mixed effects generalized linear models separately estimated the effect of aggregate spinal pathology and LMM quality. Mediation models estimated the direct and indirect effects of pathology on leg pain, and pathology and LMM quality on leg pain, respectively. Multivariable analysis identified a leg pain rating change of 0.99 [0.14; 1.84] (unstandardized beta coefficients [95% CI]) in the presence of ≥ 4 pathologies, and a disability rating change of - 0.65 [- 0.14; - 1.16] for each 10% increase in muscle quality, but no effect on back pain intensity. Muscle quality had a non-significant mediating role (13.4%) between pathology and leg pain intensity. The number of different pathologies present demonstrated a small effect on 12-month leg pain intensity outcomes, while higher LMM quality had a direct effect on 12-month disability ratings but no mediating effect between pathology and leg pain. The relations between degenerative pathology, LMM quality, and pain-related outcomes appear complex and may include independent pathways.

The Clinical Significance of the Modic Changes Grading Score

STUDY DESIGN

Cross-sectional retrospective observational study.

OBJECTIVE

To evaluate the reliability and clinical utility of the Modic changes (MC) grading score.

METHOD

Patients from the Danish national spine registry, DaneSpine, scheduled for lumbar discectomy were identified. MRI of patients with MC were graded based on vertical height involvement: Grade A (<25%), Grade B (25%-50%), and Grade C (>50%). All MRIs were reviewed by 2 physicians to evaluate the reliability of the MC grade.

RESULTS

Of 213 patients included, 142 patients had MC, 71 with MC-1 and 71 with MC-2; 34% were Grade A, 45% were Grade B, and 21% were Grade C. MC grade demonstrated substantial intra-rater (κ = .68) and inter-rater (κ = .61) reliability. A significantly higher proportion (n = 40, 57%) of patients with MC-1 had a severe MC grade compared to patients with MC-2 (n = 30, 43%, P < .001). Severe MC grade was associated with the presence of severe lumbar disc degeneration (DD) (Pfirrmann grade = V, P = .024), worse preoperative ODI (52.49 vs 44.17, P = .021) and EQ-5D scores (.26 vs .46, P = .053). MC alone including type was not associated with a significant difference in patient-reported outcomes (P > .05).

CONCLUSION

The MC grade score was demonstrated to have substantial intra- and inter-observer reliability. Severe MC grade was associated with both severe DD and MC type, being more prevalent in patients with MC-1. The MC grade was also significantly associated with worse disability and reduced health-related quality of life. Results from the study suggest that MC grade is more clinically important than MC type.

The association between vertebral endplate defects, subchondral bone marrow changes, and lumbar intervertebral disc degeneration: a retrospective, 3-year longitudinal study

PURPOSE

To investigate the influence of vertebral endplate defects and subchondral bone marrow changes on the development of lumbar intervertebral disc degeneration (DD).

METHODS

Patients > 18 y/o without any history of lumbar fusion who had repeat lumbar magnetic resonance imaging scans primarily for low back pain (LBP) performed at a minimum of 3 years apart at a single institution, and no spinal surgery in between scans were included. Total endplate score (TEPS), Modic changes (MC), and Pfirrmann grading (PFG) per lumbar disc level were assessed. DD was defined as PFG ≥ 4.

RESULTS

Three hundred and fifty-three patients (54.4% female) were included in the final analysis, comprising 1765 lumbar intervertebral discs. The patient population was 85.6% Caucasian with a median age of 60.1 years and a body mass index (BMI) of 25.8 kg/m2. A cutoff score of 5 was identified for the TEPS above which both the prevalence of DD and the odds of developing DD increased. The probability of developing DD did not differ significantly between lumbar disc levels (P = 0.419). In the multivariable analysis with adjustments for age, sex, race, body mass index (BMI), MC, TEPS cutoff > 5, and spinal level, only age (OR = 1.020; P = 0.002) was found to be an independent risk factor for developing intervertebral DD.

CONCLUSION

Our results suggest that TEPS does not unequivocally predict intervertebral DD in patients with LBP, since higher degrees of endplate defects might also develop secondarily to DD, and MC tend to occur late in the cascade of degeneration.

Some magnetic resonance imaging findings may predict future low back pain and disability: a systematic review

QUESTIONS

Do magnetic resonance imaging (MRI) findings predict future low back pain (LBP), associated disability and global recovery in people with current LBP? Do MRI findings predict these outcomes in people with no current LBP? Do MRI findings predict these outcomes in a mixed sample of people with and without current LBP?

DESIGN

This review is an update of a previous systematic review investigating the relationship between lumbar spine MRI findings and future LBP.

PARTICIPANTS

People with or without LBP with lumbar MRI scans.

OUTCOME MEASURES

MRI findings, pain and disability.

RESULTS

Of the included studies, 28 reported on participants with current LBP, eight reported on participants with no LBP and four reported on a mixed sample. Most results were based on single studies and did not demonstrate clear relationships between MRI findings and future LBP. In populations with current LBP, pooling demonstrated that the presence of Modic type 1 changes alone or Modic type 1 and 2 changes were associated with slightly worse pain or disability outcomes in the short term, and the presence of disc degeneration was associated with worse pain and disability outcomes in the long term. In populations with current LBP, pooling demonstrated no evidence of an association between the presence of nerve root compression and disability outcomes in the short term, and no evidence of an association between the presence of disc height reduction, disc herniation, spinal stenosis, high-intensity zone and clinical outcomes in the long term. In populations with no LBP, pooling demonstrated that the presence of disc degeneration may increase the likelihood of experiencing pain in the long term. In mixed populations, no pooling was possible; however, single studies demonstrated that Modic type 1, 2 or 3 changes and disc herniation were each associated with worse pain in the long term.

CONCLUSIONS

The results suggest that some MRI findings may have weak associations with future LBP; however, larger high-quality studies are needed to resolve uncertainty.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021252919.

MRI grading of spinal stenosis is not associated with the severity of low back pain in patients with lumbar spinal stenosis

Background

Although lumbar spinal stenosis (LSS) often coexists with other degenerative conditions, few studies have fully assessed possible contributing factors for low back pain (LBP) in patients with LSS. The purpose of this study was to identify factors associated with the severity of LBP in patients with LSS.

Methods

The patients with neurogenic claudication caused by LSS, which was confirmed by magnetic resonance imaging (MRI) were included in this cross-sectional study. Data included ratings of LBP, buttock and leg pain, and numbness on a numerical rating scale (NRS), 36-item Short-Form Survey (SF-36) scores, muscle mass measured by bioelectrical impedance analysis, and radiographic measurements including lumbopelvic alignment and slippage. The severity of LSS, endplate defects, Modic endplate changes, intervertebral disc degeneration, and facet joint osteoarthritis were evaluated on MRI. Spearman correlation and multivariate linear regression analyses were used to examine the factors associated with the severity of LBP (NRS score).

Results

A total of 293 patients (135 male and 158 female, average age 72.6 years) were analyzed. LBP was moderately correlated with buttock and leg pain, and buttock and leg numbness. Significant but weak correlations were observed between LBP and body mass index, appendicular and trunk muscle mass, all domains of SF-36, pelvic tilt, total number of endplate defects and Modic endplate changes, and summary score of disc degeneration grading, but not severity or number of spinal stenoses. In the multivariate regression analysis, age, female sex, trunk muscle mass, diabetes, NRS buttock and leg pain, NRS buttock and leg numbness, SF-36 vitality, pelvic tilt, and total number of endplate defects were associated with the severity of LBP.

Conclusions

Trunk muscle mass, lumbopelvic alignment, and endplate defects, but not severity of stenosis are partly associated with severity of LBP, but buttock and leg pain and buttock and leg numbness have strongest relationships with LBP in patients with LSS.

Endplate defects, not the severity of spinal stenosis, contribute to low back pain in patients with lumbar spinal stenosis

BACKGROUND CONTEXT

It is controversial whether lumbar spinal stenosis (LSS) itself contributes to low back pain (LBP). Lower truncal skeletal muscle mass, spinopelvic malalignment, intervertebral disc degeneration, and endplate abnormalities are thought to be related to LBP. However, whether these factors cause LBP in patients with LSS is unclear.

PURPOSE

To identify factors associated with LBP in patients with LSS.

STUDY DESIGN/SETTING

Cross-sectional design.

PATIENT SAMPLE

A total of 260 patients (119 men and 141 women, average age 72.8 years) with neurogenic claudication caused by LSS, as confirmed by magnetic resonance imaging (MRI).

OUTCOME MEASURES

Ratings of LBP, buttock and leg pain, and numbness on a numerical rating scale (NRS), 36-Item Short Form Survey (SF-36) scores, muscle mass measured by bioelectrical impedance analysis, and radiographic measurements including slippage and lumbopelvic alignment. The severity of LSS, endplate defects, Modic endplate changes, intervertebral disc degeneration, and facet joint osteoarthritis were assessed on MRI.

METHODS

The presence of LBP was defined as an NRS score ≥3. The demographic data, patient-reported outcomes, and radiological and MRI findings were compared between patients with and without LBP. Multivariate logistic regression analysis was used to identify the factors that were independently associated with the presence of LBP.

RESULTS

There were significant differences between patients with and without LBP for buttock and leg pain and numbness on the NRS, general health on the SF-36, presence of endplate defects, presence of Modic changes, disc degeneration grading, and disc height grading (all p < .05). Multivariate logistic regression analysis showed significant associations between LBP and diabetes (OR 2.43; 95% CI 1.07-5.53), buttock and leg numbness on the NRS (OR 1.34; 95% CI 1.17-1.52), general health on the SF-36 (OR 0.97; 95% CI 0.95-0.99), and the presence of erosive endplate defects (OR 3.04; 95% CI 1.51-6.11) (all p < .05).

CONCLUSIONS

These results suggest that LBP in patients with LSS should be carefully assessed not only for spinal stenosis but also clinical factors and endplate defects.

Association of Lumbar MRI Findings with Current and Future Back Pain in a Population-based Cohort Study

STUDY DESIGN

Population-based cohort study.

OBJECTIVE

We examined associations between common lumbar degenerative changes observed on magnetic resonance imaging (MRI) and present or future low back pain (LBP).

SUMMARY OF BACKGROUND DATA

The association between lumbar MRI degenerative findings and LBP is unclear. Longitudinal studies are sparse.

METHODS

Participants (n = 3369) from a population-based cohort study were imaged at study entry, with LBP status measured at baseline and 6-year follow-up. MRI scans were reported on for the presence of a range of MRI findings. LBP status was measured on a 0 to 10 scale. Regression models were used to estimate the cross-sectional and longitudinal associations between individual and multiple MRI findings and LBP severity. Separate longitudinal analyses were conducted for participants with and without baseline pain.

RESULTS

MRI findings were present in persons with and without back pain at baseline. Higher proportions were found in older age groups. 76.4% of participants had a least one MRI finding and 8.3% had five or more different MRI findings. Cross-sectionally, most MRI findings were slightly more common in those with LBP and pain severity was slightly higher in those with MRI findings (ranging from 0.06 for high intensity zone to 0.83 for spondylolisthesis). In the longitudinal analyses, we found most MRI findings were not associated with future LBP-severity regardless of the presence or absence of baseline pain. Compared to zero MRI findings, having multiple MRI findings (five or more) was associated with mildly greater pain-severity at baseline (0.84; 0.50-1.17) and greater increase in pain-severity over 6 years in those pain free at baseline (1.21; 0.04-2.37), but not in those with baseline pain (-0.30; -0.99 to 0.38).

CONCLUSION

Our study shows that the MRI degenerative findings we examined, individually or in combination, do not have clinically important associations with LBP, with almost all effects less than one unit on a 0 to 10 pain scale.Level of Evidence: 3.

Low back pain scores correlate with the cytokine mRNA level in lumbar disc biopsies: a study of inflammatory markers in patients undergoing lumbar spinal fusion

PURPOSE

The molecular mechanism behind pain in degenerative disc disease (DDD) and chronic low back pain (LBP) patients is largely unknown. This present study examines the association of LBP and disability to mediators of the inflammatory cascade, as indexed by mRNA gene expression of pro-inflammatory cytokine markers in the intervertebral disc (IVD).

METHODS

Biopsies of the annulus fibrosus (AF) and the nucleus pulposes (NP) from patients with DDD undergoing 1-2 level fusion surgery at L4/L5 or L5/S1 were obtained from total of 34 patients [9 M, 25 F] with average age of 53 [32-63]. The mRNA expression of TNF-α, IL-1β, and IL-6 in the AF and NP was analyzed using quantitative real-time polymerase chain reaction (RT-qPCR), and the expression level of these markers was correlated to the visual analogue scale (VAS) and Oswestry Disability Index (ODI) scores (0-100) for pain and disability.

RESULTS

We report a statistically significant positive correlation between pain intensity (VAS score) and the expression of TNF-α in both the AF (r = 0.54, p = 0.001) and NP (r = 0.40, p = 0.02), similarly with IL-1β in AF (r = 0.37, p = 0.02) and IL-6 in NP (r = 0.40, p = 0.02). In addition, we found significant positive correlation observed between disability score (ODI) and expression of IL-6 in both AF (r = 0.36, p = 0.03) and NP (r = 0.41, p = 0.01).

CONCLUSION

We conclude that the intensity of LBP and disability is associated with the level of inflammation in the disc.