Severe Lumbar Intervertebral Disc Degeneration Is Associated with Modic Changes and Fatty Infiltration in the Paraspinal Muscles at all Lumbar Levels, Except for L1-L2: A Cross-Sectional Analysis of 50 Symptomatic Women and 50 Age-Matched Symptomatic Men

Low back pain is a common public health problem associated with lumbar intervertebral disc degeneration. It is still unclear, however, whether intervertebral disc degeneration is an isolated process or accompanied by other degenerative events. We analyzed whether disc degeneration was associated with vertebral end-plate changes and fatty infiltration in the paraspinal muscles. We also aimed to identify whether the severity of disc degeneration influenced this association. Intervertebral disc degeneration, vertebral end-plate changes, and fatty infiltration in the multifidus, erector spinae, and psoas muscles at all lumbar intervertebral disc levels were evaluated on lumbar spine magnetic resonance images of 50 symptomatic women and 50 age-matched symptomatic men. The women had greater lumbar intervertebral disc degeneration scores at L4-L5 and L5-S1 and in total. The women had more fatty infiltration in the multifidus and erector spinae muscles at L4-L5 and L5-S1. The men had more fatty infiltration in the psoas muscle at L5-S1. Patients with severe intervertebral disc degeneration were more likely to have increased fatty infiltration in the multifidus and erector spinae muscles. The rate of vertebral end-plate changes was also greater in the patients with severe intervertebral disc degeneration. Severe disc degeneration in the lumbar spine is closely associated with Modic changes and fatty infiltration in the multifidus and erector spinae muscles. We suggest that disc degeneration is not an isolated event but, rather, a continuum of events that could more clearly be shown in future prospective, large sample-size studies.