The disc-endplate-bone-marrow complex classification: progress in our understanding of Modic vertebral endplate changes and their clinical relevance

The Relationship Between Modic Changes and Endplate Sclerosis in Patients with Lumbar Degenerative Disease: A Systematic Review and Network Meta-Analysis

OBJECTIVE

To explore the relationship between modic changes (MCs) and endplate sclerosis in patients with lumbar degenerative disease.

METHODS

This network meta-analysis was performed on the basis of Preffered Reporting Items for Systematic Reviews and Meta-Analysis 2020 statement. This study was registered at the International Prospective Register of Systematic Reviews (CRD42024497370). We performed a systematic search of the PubMed, Web of Science, Embase, China national knowledge infrastructure, China Science and Technology Journal Database, and Wanfang databases from inception to December 22, 2023. STATA13.0 and RevMan 5.3 were applied to perform the meta-analysis.

RESULTS

Seven studies with a total of 1510 endplates were divided into 6 groups according to the type of MCs. The endplate sclerosis rate in the single-type group was significantly lower than that in the mixed-type group. The endplate sclerosis rate in the type I MC (MC1) was significantly lower than that in the type II MC (MC2). The endplate sclerosis rate in the MC2 was significantly lower than that in the type III MC (MC3). The endplate sclerosis rate in the MC1/2 was significantly lower than that in the MC2/3. No significant difference was detected between MC1/2 and MC1/3 or between MC2/3 and MC1/3. For decreasing the endplate sclerosis rate, the order of the different types of MCs was MC1>MC2>MC1/2>MC2/3≈MC1/3>MC3.

CONCLUSIONS

Endplate sclerosis occurs in all kinds of MCs. With increasing grade of MCs, the incidence of endplate sclerosis gradually increased. The endplate sclerosis rate in mixed-type MCs was significantly greater than that in MC2 and significantly lower than that in MC3. The endplate sclerosis rate in the mixed-type, including MC3 (MC1/3 and MC2/3), was significantly greater than that in the MC1/2.

The role of the complement system in disc degeneration and Modic changes

Disc degeneration and vertebral endplate bone marrow lesions called Modic changes are prevalent spinal pathologies found in chronic low back pain patients. Their pathomechanisms are complex and not fully understood. Recent studies have revealed that complement system proteins and interactors are dysregulated in disc degeneration and Modic changes. The complement system is part of the innate immune system and plays a critical role in tissue homeostasis. However, its dysregulation has also been associated with various pathological conditions such as rheumatoid arthritis and osteoarthritis. Here, we review the evidence for the involvement of the complement system in intervertebral disc degeneration and Modic changes. We found that only a handful of studies reported on complement factors in Modic changes and disc degeneration. Therefore, the level of evidence for the involvement of the complement system is currently low. Nevertheless, the complement system is tightly intertwined with processes known to occur during disc degeneration and Modic changes, such as increased cell death, autoantibody production, bacterial defense processes, neutrophil activation, and osteoclast formation, indicating a contribution of the complement system to these spinal pathologies. Based on these mechanisms, we propose a model how the complement system could contribute to the vicious cycle of tissue damage and chronic inflammation in disc degeneration and Modic changes. With this review, we aim to highlight a currently understudied but potentially important inflammatory pathomechanism of disc degeneration and Modic changes that may be a novel therapeutic target.

Evaluation of the Reproducibility of MR Elastography Measurements of the Lumbar Back Muscles

BACKGROUND

MR elastography (MRE) may provide quantitative imaging biomarkers of lumbar back muscles (LBMs), complementing MRI in spinal diseases by assessing muscle mechanical properties. However, reproducibility analyses for MRE of LBM are lacking.

PURPOSE

To assess technical failure, within-day and inter-day reproducibility, robustness with the excitation source positioning, and inter-observer agreement of MRE of muscles.

STUDY TYPE

Prospective.

SUBJECTS

Seventeen healthy subjects (mean age 28 ± 4 years; 11 females).

FIELD STRENGTH/SEQUENCE

1.5 T, gradient-echo MRE, T1-weighted turbo spin echo.

ASSESSMENT

The pneumatic driver was centered at L3 level. Four MRE were performed during two visits, 2-4 weeks apart, each consisting of two MRE with less than 10 minutes inter-scan interval. At Visit 1, after the first MRE, the coil and driver were removed, then reinstalled. The MRE was repeated. At Visit 2, following the first MRE, only the driver was moved down 5 cm. The MRE was repeated. Two radiologists segmented the multifidus and erector spinae muscles.

STATISTICAL TESTS

Paired t-test, analysis of variance, intraclass correlation coefficients (ICCs). P-values <0.05 were considered statistically significant.

RESULTS

Mean stiffness of LBM ranged from 1.44 to 1.60 kPa. Mean technical failure rate was 2.5%. Inter-observer agreement was excellent (ICC ranging from 0.82 [0.64-0.96] to 0.99 [0.98-0.99] in the multifidus, and from 0.85 [0.69-0.92] to 0.99 [0.97-0.99] in the erector spinae muscles). Within-day reproducibility was fair in the multifidus (ICC: 0.53 [0.47-0.77]) and good in the erector spinae muscles (ICC: 0.74 [0.48-0.88]). Reproducibility after moving the driver was excellent in both multifidus (ICC: 0.85 [0.69-0.93]) and erector spinae muscles (ICC: 0.84 [0.67-0.92]). Inter-day reproducibility was excellent in the multifidus (ICC: 0.76 [0.48-0.89]) and poor in the erector spinae muscles (ICC: 0.23 [-0.61 to 0.63]).

DATA CONCLUSION

MRE of LBM provides measurements of stiffness with fair to excellent reproducibility and excellent inter-observer agreement. However, inter-day reproducibility in the multifidus muscles indicated that the herein used MRE protocol may not be optimal for this muscle.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 1.