Correlation between the severity of lumbar spinal stenosis and lumbar paraspinal muscle atrophy

To investigate the correlation between the severity of lumbar spinal stenosis (LSS) and the atrophy of lumbar paraspinal muscles.

A retrospective analysis was conducted on 200 patients with LSS (stenosis group) and 60 individuals without lumbar spine disease (control group) treated at the Department of Orthopedics, Kunming Traditional Chinese Medicine Hospital, from January 2022 to October 2024. Using a 1.5T MRI system, we measured the total cross-sectional area (TCSA) and total fat-free cross-sectional area (TFCSA) of the multifidus, erector spinae, and psoas major muscles. Muscle atrophy was evaluated using the TFCSA/TCSA ratio, and its correlation with LSS severity was analyzed.

The stenosis group showed significantly lower TFCSA/TCSA ratios in the multifidus, erector spinae, and psoas major compared to controls (P<0.05). LSS severity was negatively correlated with the TFCSA/TCSA ratios of the multifidus (r=-0.504, P<0.05) and erector spinae (r=-0.562, P<0.05), but not with the psoas major (P>0.05). Similarly, the number of stenotic segments was negatively correlated with multifidus (r=-0.381) and erector spinae (r=-0.420) atrophy (P<0.05). TFCSA/TCSA ratios were significantly lower on the symptomatic side for all three muscles (all P<0.05).

The severity and extent of LSS are significantly associated with atrophy of the multifidus and erector spinae, but not the psoas major. Greater muscle atrophy corresponds to a higher number of stenotic segments.