Characteristics of paraspinal muscle degeneration in degenerative diseases of the lumbar spine at different ages.

Objective: To analyze the relationship between gender, age, and the degree of lumbar degenerative disease.

Methods: 290 patients with Lumbar spinal stenosis and sciatica were analyzed. Sixty patients without sciatica were collected in the control group. Patient demography including age, gender, body mass index (BMI), serum calcium, and triglyceride level was acquired. The cross-sectional area (CSA) and percentage of fat infiltration area (Intermuscular adipose tissue (IMat%) of paraspinal muscles at the L4-5 level were measured using MRI imaging. The patients were divided into five age groups: A (18-30 years old), B (31-40 years old), C (41-50 years old), D (51-60 years old), and E (> 60 years old). Analysis of variance (ANOVA) and LSD was used to analyze differences among subgroups. Student's t-test was used to compare MCSA and fat CSA in the two groups. P < 0.05 was statistically significant.

Results: The paraspinal muscle CSA (MCSA) was significantly smaller in women (P < 0.05). Older age was associated with less MCSA and greater fatty infiltration in erector spinae and multifidus (MF) muscle (P < 0.05). Serum calcium and BMI were positively correlated with CSA of erector spinae muscle (P < 0.05), but not with muscle fat infiltration (P > 0.05). Although there was no significant difference in MCSA between the two groups, the fat infiltration (IMat%) in the disease group was significantly higher than in the control group (p < 0.05).

Conclusion: Lumbar degenerative diseases caused the degeneration of the paravertebral muscles, which mainly resulted in increased intramuscular fat infiltration, rather than changes in the overall MCSA.