• To identify potential determinants of Modic changes and their association with disc degeneration and low back pain among Southern Chinese

Mok et al.

This recently published, population based cross sectional study by Mok et al, looked at the prevalence and risk factors associated with Modic changes in the lumbar spine among Southern Chinese subjects.

This is one of the largest studies in regards to the number of patients included (N=2449) looking at Modic changes.   One of the study limitations is that the study methods did not allow for differentiation of different Modic types.   One could also argue about  subjectivity in the MRI grading scheme that was utilized, which could change some of the point estimates.

The prevalence of Modic changes in this study was 5.8% (N=141). This is considerably lower than other studies By Maatta et al (Spine J 2015)  21.9% of 1546 Southern Chinese volunteers,  Martinez-Quinones et al (J Spinal Disorder Tech 2014) 13.05% of 450 working young adults, and Wang et al (Spine J 2012) 55.6% of 561 subjects from a Finnish population.

The presence of Modic changes at the L4-5 and L5-S1 levels in this study by Mok et al was associated with age, disc degeneration, disc herniation, and history of lumbar injury.   Also, smokers and obesity were associated with increased prevalence of Modic changes in the lower lumbar spine. This in contrast to the presence of Modic changes seen in the upper lumbar spine (L1-2, L2-3, L3-4) where only disc displacement was commonly associated.

The authors of this study did strengthen the overall conclusions by adjusting for multiple potential confounders including age, gender, participation in sports, occupation, smoking status, BMI, presence of Schmorl’s nodes, spondylolisthesis, and disc degeneration sum score.

As this was a cross sectional study, there were several major limitations. This study design only allows for a “snapshot” at a single point in time, thereby making it impossible to determine a cause and effect relationship along with the actual incidence of Modic changes. This type of study can be affected by recall bias. Subjects were questioned about the presence of low back pain (defined as 2 weeks of continuous, localized pain with sciatica). As this population was made up of volunteers with no specific inclusion or exclusion criteria, the presence of lumbar pain for a short duration in the past, may have been forgotten by some subjects.    As previously discussed, the authors were unable to stratify Modic changes into the different subtypes.  This was based on a Southern Chinese population which may not be representative of other adult populations and therefore generalizability of this study is limited.

While there does appear to be an association between Modic changes of the lumbar spine and clinical symptoms related to back pain, the true strength of this relationship remains somewhat elusive and may differ by cultural origin.