Modic changes are characteristic alterations observed in the bone marrow of the vertebral bodies, adjacent to the intervertebral discs. They are detected on magnetic resonance imaging (MRI) and are closely associated with degenerative disc disease.
They are classified into three types according to the stage and nature of the underlying pathological process. Modic type 1 changes represent bone marrow edema and inflammation and are considered to be more closely associated with active degenerative processes and symptomatic pain. Modic type 2 changes correspond to fatty replacement of the bone marrow, indicating a more chronic and relatively stabilized condition. Modic type 3 changes represent subchondral bone sclerosis, corresponding to the most advanced stage of degenerative alteration.
Their exact cause has not been fully established; however, they are thought to be related to mechanical instability of the intervertebral disc, repetitive microtrauma, and possible involvement of low-grade inflammatory or infectious processes.
The presence of Modic changes, particularly type 1, has been associated in some studies with an increased likelihood of chronic low back pain, although the exact cause-and-effect relationship remains debated in the scientific literature.
Identification of Modic changes on MRI represents an important complementary finding in the evaluation of patients with chronic low back pain. However, their presence alone does not indicate a specific treatment strategy, as management is determined primarily by the overall clinical condition, symptoms, and functional limitations of each patient.