[Imaging study of lumbosacral multifidus muscle fat changes in patients with lumbar disc herniation]

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

Magnetic Resonance Spectroscopy was performed on the multifidus muscle of 35 healthy volunteers and 35 patients with unilateral L_4,5 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/m²; in the patients, the mean age was (36.09±7.70) years old, the BMI was (21.50±1.78) kg/m², 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_4,5 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.

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 (P>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 (P<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 (P<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 (P>0.05).

There is degeneration of lumbosacral multifidus muscle on the affected side of patients with unilateral L_4,5 intervertebral disc herniation, featuring multifidus muscular atrophy and fat infiltration.