[Imaging Study of Lumbosacral Multifidus Muscle Fat Changes in Patients with Lumbar Disc Herniation]

Objective: To compare the degeneration of lumbosacral multifidus muscle in patients with lumbar disc herniation.

Methods: Magnetic Resonance Spectroscopy was performed on the multifidus muscle of 35 healthy volunteers and 35 patients with unilateral L lumbar disc herniation. There were 20 males and 15 females in each group, aged from 25 to 55 years old. In healthy volunteers, the mean age was (35.66±8.73) years old and the BMI was (21.85±1.94) kg/m; in the patients, the mean age was (36.09±7.70) years old, the BMI was (21.50±1.78) kg/m, the VAS score was (4.40±0.88) points, the course of disease was (11.2±7.14) months. The proportion of fat in the L lumbosacral multifidus muscle and the proportion of fat-suppressed cross-sectional area were observed by MRI, the differences of the observation indexes of the two groups were compared through data analysis.

Results: In healthy volunteers, the proportion of fat on the left side of the multifidus muscle was (0.169± 0.035)%, the proportion of fat removal cross-sectional area on the left side of the multifidus muscle was (0.699±0.070)%, the proportion of fat on the right side of the multifidus muscle was (0.168±0.031)%, and the proportion of fat removal cross-sectional area on the right side of the multifidus muscle was (0.712±0.056)%, there was no significant difference between the two sides (>0.05). In patients, the proportion of fat on the healthy side of multifidus muscles was (0.173±0.021)%, the proportion of fat removal cross-sectional area on the healthy side of multifidus muscles was (0.695±0.054)%, the proportion of fat on the affected side of the multifidus muscle was (0.228±0.027)%, and the proportion of fat removal cross-sectional area on the affected side of the multifidus muscle was (0.629±0.048)%, the differences of the above indexes on both sides were statistically significant (<0.05). There was a statistically significant difference in the proportion of multifidus muscle fat and the ratio of fat-suppressed cross-sectional area between the affected side and volunteers (<0.05). There was no significant difference in fat ratio and fat-suppressed cross sectional area ratio between the left and right sides of healthy volunteers and healthy side of patients (>0.05).

Conclusion: There is degeneration of lumbosacral multifidus muscle on the affected side of patients with unilateral L intervertebral disc herniation, featuring multifidus muscular atrophy and fat infiltration.