Correlation of Size and Type of Modic Types 1 and 2 Lesions With Clinical Symptoms

Abstract

Intensity of pain and level of disability (Oswestry Disability Index [ODI]) were compared with the relative size of Modic type 1 (M1) and Modic type 2 (M2) lesions. Clinical symptoms of patients having mixed M1-M2 lesion (n = 49) were compared with patients having a "pure" M1 lesion (n = 13). To determine the relation of the sizes of M1 and M2 lesions and the type of Modic lesion (mixed M1-M2 or pure M1 lesion) with intensity of low back pain and level of perceived disability. Endplate signal abnormalities, particularly M1 changes indicating edema and inflammation, have been suggested to play an important role in the etiopathogenesis of a subgroup of patients with nonspecific chronic low back pain (CLBP). However, their association with clinical symptoms has not been studied in detail previously. Sixty-two CLBP patients with a large M1 lesion were selected from CLBP patients who were sent for the first time for standard lumbar spine magnetic resonance imaging at a university hospital. To exclude other causes of CLBP, as far as possible, strict exclusion criteria were used: any specific back disease, even a slight nerve root compression, a recent or major spine operation, or age older than 65 years. The relative sizes of M1 and M2 lesions were visually estimated from sagittal images for comparison with clinical symptoms. The majority of patients (91.9%; 57 of 62) had an M1 lesion at a single level, 92% of the lesions being at L4-L5 or L5-S1 level. Forty-nine patients (79.0%) had a mixed M1-M2 lesion, and 13 (21.0%) had a pure M1 lesion. The mean of the pain intensity score was 6.2, and, correspondingly, the Oswestry Disability Index was 30.4. The mean relative sagittal area of the largest M1 lesion was 24.6% (SD = 16.2), and that of the M2 lesion was 10.9% (SD = 11.6). Neither the pain intensity nor the ODI scores were found to correlate with the largest relative size of the M1 lesion. The patients with "pure" M1 lesion had statistically significantly more clinical symptoms than patients having a mixed M1-M2 lesion. We conclude that the size of M1 lesion does not directly correlate with the clinical symptoms but that the type of Modic lesion is more important. This study supports the previous observations that when the inflammatory process turns to the mixed M1-M2 lesions, clinical symptoms decrease.