A study of Modic changes in 228 middle-aged male workers found a strong association between LBP frequency and intensity and Modic changes observed on magnetic resonance imagery (MRI) scans. These Modic chances were most likely to be at the L5-S1 spinal level and were more strongly correlated with LBP symptoms when Type 1 lesions were present.
What’s at Stake?
Bone marrow lesions—also known as vertebral endplate changes— that are visible on MRIs are considered evidence of disc degeneration. There are three types of lesions recognized by Modic: Type 1, where fissuring and an increase in the subchondral marrow vascularity is apparent; Type 2, where there is fatty degeneration of the bone marrow; and Type 3, where subchondral bone sclerosis is suspected.
Previous studies seeking to establish a positive correlation between Modic changes and clinical LBP symptoms have been inconclusive due to flawed designs and/or limited subject pools. This cross-sectional study used middle-aged male workers to investigate how or if Modic changes affected the intensity and frequency of sciatica and LBP in its subjects.
The subjects involved in this study were all male—128 Finnish train engineers, and 69 Finnish paper mill and chemical factory workers—with a mean age of 47 years. The train engineers had worked at their jobs, which involved long hours of standing and approximately five hours per day of subjection to intense, whole-body vibrations, an average of 21 years. The control group of chemical and paper workers claimed a mostly sedentary experience during their working hours and were not exposed to intense vibrations while on the job.
Both groups were assessed prior to the MRI study about the number of prior LBP and leg pain episodes, particularly those with a duration of 14 days or more. They were asked to comment on the pain’s intensity over the past week and over a three-month period before the study. They were also questioned about any history of LBP and whether they were experiencing LBP on the day of the assessment. MRI scans were taken and analyzed by two radiologists with no knowledge of the names or histories of the scanned subjects. Modic changes were identified and sorted into groups based upon the three types, with mixed types (I and I/II, and II and II/III) combined, representing more active and less active degeneration types. Other disc irregularities were noted independently and blinded to the clinical data analysts when observed. Disc herniation was either normal, bulging, protrusion, or extrusion in the notation. Neural compromise was identified as no compromise, nerve root contact, or compression. Stenosis was defined and noted according to Willen et al criteria.
Though the engineers reported the highest sciatica and 1 week and 3-month pain scores, Modic changes at one or more levels were like those observed in the control group—roughly 56%. In the combined groups, 15 % of the subjects showed Modic Type I changes only, and 32% had Modic II changes at one or more-disc levels. Ten percent showed Type 1 or II changes at the same, or separate levels. The combined subject groups had 178 Modic changes across various lumbar levels, with 30 % experiencing Type I and 66 % Type II. None of the scans showed Type III Modic changes. Eighty percent of all Modic changes were located at L4-5, or L5/S1 levels, and 61% of these changes were described as “extensive,” while 39% were minimal.
There was a positive correlation between the reports of LBP episodes—especially those experienced within the past week and three-month period prior to the study— and observed Modic changes at any level. Modic changes at the L5-S1 levels were positively correlated with previous LBP and/or sciatica, especially where high levels of pain were reported within the past week prior to the study. There was little-to-no correlation between reported pain and Modic changes at higher disc levels or at L4/5.
Type II changes at any level was positively correlated with a higher number of previous LBP, especially episodes occurring during the past week or three-month period prior to the study.
Extensive changes were positively associated with more LBP episodes in the past and higher levels of LBP or sciatica within the past week or three months prior to the study. This was especially true when extensive Modic changes were found at the L5-S1 levels or when minimal changes were noted, but the subject had an extensive history of LBP episodes. The LBP had little correlation with the extent of the Modic changes at upper spinal disc levels or at L4/5.
The results of the study—the first to analyze Modic changes as they relate to specific IVD levels— suggest that there is a positive correlation between Modic changes occurring at the L5-S1 IVD level and that LBP is more likely to be associated with Modic Type 1 lesions at this level than at other levels or with other lesion types. The authors of the study suggest more research—particularly of how Modic changes correlate with pain in a younger subject set—is necessary to verify these findings.