gms | German Medical Science

Objectives: Factors influencing paraspinal muscle degeneration are still not well understood. Fatty infiltration (FI) is known to be one main feature of the degeneration cascade. The aim of this study was to illustrate the cluster of paraspinal lumbar muscle degeneration on MRI.

Methods: Mono-, Pluri- and Multi-segmental lumbar muscles groups were segmented on T2-weighted MR sequences using a novel semiautomatic technique for quantitative muscle/fat discrimination. The degree of fatty infiltration of t3 predefined muscle groups was compared on a 3-dimensional basis, with regard to segment involvement, age and disc degeneration. General linear models were utilized for statistical comparison.

Results: N=78 segments (age: 52.7; range 16 - 87 years) could be included. The average fatty infiltration of the mono-segmental muscles (21.1%) was significantly higher compared to the multi- (16.0%) and pluri-segmental (8.5%) muscles. Muscles on the levels L4/5 (p=0.09) and L5/S1 (p=0.016) showed a significant higher amount of fat compared to the levels L2/3 and L3/4 if degeneration was present. Higher age (p=0.039) and disc degeneration (0.025) were co-variables associated with increased fatty infiltration.

Conclusion: The complexity of the problematic issue of lower back pain is likely to be beyond the horizon of a simple bony disease. Muscle affection which was shown to correlate will to the degree of degeneration, may truly play a more important role than yet perceived by the general spinal community and would necessitate increased attention in the future.